diff --git a/.hgtags b/.hgtags
index fce3720..dfe844f 100644
--- a/.hgtags
+++ b/.hgtags
@@ -422,3 +422,4 @@
 47cca243d0ed39bf5dcb9859184affc958b79b6f release-1.13.7
 20ca4bcff108d3e66977f4d97508637093492287 release-1.13.8
 fb1212c7eca4c5328fe17d6cd95b010c67336aac release-1.13.9
+31c929e16910c38492581ef474e72fa67c28f124 release-1.13.10
diff --git a/BUILD b/BUILD
index d9ca7b1..01e88fc 100644
--- a/BUILD
+++ b/BUILD
@@ -412,6 +412,7 @@
         "src/http/ngx_http_write_filter_module.c",
         "src/http/v2/ngx_http_v2.c",
         "src/http/v2/ngx_http_v2.h",
+        "src/http/v2/ngx_http_v2_encode.c",
         "src/http/v2/ngx_http_v2_filter_module.c",
         "src/http/v2/ngx_http_v2_huff_decode.c",
         "src/http/v2/ngx_http_v2_huff_encode.c",
@@ -625,6 +626,21 @@
 )
 
 cc_library(
+    name = "http_grpc",
+    srcs = [
+        "src/http/modules/ngx_http_grpc_module.c",
+    ],
+    copts = nginx_copts,
+    defines = [
+        "NGX_HTTP_GRPC",
+    ],
+    deps = [
+        ":core",
+        ":http",
+    ],
+)
+
+cc_library(
     name = "http_gunzip",
     srcs = [
         "src/http/modules/ngx_http_gunzip_filter_module.c",
@@ -1365,6 +1381,7 @@
         ":http_fastcgi",
         ":http_flv",
         ":http_geo",
+        ":http_grpc",
         ":http_gunzip",
         ":http_gzip_filter",
         ":http_gzip_static",
@@ -1485,5 +1502,5 @@
     preinst = "@nginx_pkgoss//:debian_preinst",
     prerm = "@nginx_pkgoss//:debian_prerm",
     section = "httpd",
-    version = "1.13.9",
+    version = "1.13.10",
 )
diff --git a/auto/modules b/auto/modules
index a8e55d5..8e14758 100644
--- a/auto/modules
+++ b/auto/modules
@@ -428,6 +428,7 @@
                          src/http/v2/ngx_http_v2_module.h"
         ngx_module_srcs="src/http/v2/ngx_http_v2.c \
                          src/http/v2/ngx_http_v2_table.c \
+                         src/http/v2/ngx_http_v2_encode.c \
                          src/http/v2/ngx_http_v2_huff_decode.c \
                          src/http/v2/ngx_http_v2_huff_encode.c \
                          src/http/v2/ngx_http_v2_module.c"
@@ -743,6 +744,17 @@
         . $NGX_AUTO/module
     fi
 
+    if [ $HTTP_GRPC = YES -a $HTTP_V2 = YES ]; then
+        ngx_module_name=ngx_http_grpc_module
+        ngx_module_incs=
+        ngx_module_deps=
+        ngx_module_srcs=src/http/modules/ngx_http_grpc_module.c
+        ngx_module_libs=
+        ngx_module_link=$HTTP_GRPC
+
+        . $NGX_AUTO/module
+    fi
+
     if [ $HTTP_PERL != NO ]; then
         ngx_module_name=ngx_http_perl_module
         ngx_module_incs=src/http/modules/perl
diff --git a/auto/options b/auto/options
index 4c9314f..8b02f54 100644
--- a/auto/options
+++ b/auto/options
@@ -86,6 +86,7 @@
 HTTP_FASTCGI=YES
 HTTP_UWSGI=YES
 HTTP_SCGI=YES
+HTTP_GRPC=YES
 HTTP_PERL=NO
 HTTP_MEMCACHED=YES
 HTTP_LIMIT_CONN=YES
@@ -262,6 +263,7 @@
         --without-http_fastcgi_module)   HTTP_FASTCGI=NO            ;;
         --without-http_uwsgi_module)     HTTP_UWSGI=NO              ;;
         --without-http_scgi_module)      HTTP_SCGI=NO               ;;
+        --without-http_grpc_module)      HTTP_GRPC=NO               ;;
         --without-http_memcached_module) HTTP_MEMCACHED=NO          ;;
         --without-http_limit_conn_module) HTTP_LIMIT_CONN=NO        ;;
         --without-http_limit_req_module) HTTP_LIMIT_REQ=NO         ;;
@@ -471,6 +473,7 @@
   --without-http_fastcgi_module      disable ngx_http_fastcgi_module
   --without-http_uwsgi_module        disable ngx_http_uwsgi_module
   --without-http_scgi_module         disable ngx_http_scgi_module
+  --without-http_grpc_module         disable ngx_http_grpc_module
   --without-http_memcached_module    disable ngx_http_memcached_module
   --without-http_limit_conn_module   disable ngx_http_limit_conn_module
   --without-http_limit_req_module    disable ngx_http_limit_req_module
diff --git a/auto/unix b/auto/unix
index be43017..b600b5e 100644
--- a/auto/unix
+++ b/auto/unix
@@ -791,6 +791,30 @@
 . $NGX_AUTO/feature
 
 
+ngx_feature="clock_gettime(CLOCK_MONOTONIC)"
+ngx_feature_name="NGX_HAVE_CLOCK_MONOTONIC"
+ngx_feature_run=no
+ngx_feature_incs="#include <time.h>"
+ngx_feature_path=
+ngx_feature_libs=
+ngx_feature_test="struct timespec ts; clock_gettime(CLOCK_MONOTONIC, &ts)"
+. $NGX_AUTO/feature
+
+
+if [ $ngx_found = no ]; then
+
+    # Linux before glibc 2.17, notably CentOS 6
+
+    ngx_feature="clock_gettime(CLOCK_MONOTONIC) in librt"
+    ngx_feature_libs="-lrt"
+    . $NGX_AUTO/feature
+
+    if [ $ngx_found = yes ]; then
+        CORE_LIBS="$CORE_LIBS -lrt"
+    fi
+fi
+
+
 ngx_feature="posix_memalign()"
 ngx_feature_name="NGX_HAVE_POSIX_MEMALIGN"
 ngx_feature_run=no
diff --git a/build.bzl b/build.bzl
index 9548c2b..28f57a2 100644
--- a/build.bzl
+++ b/build.bzl
@@ -663,7 +663,7 @@
         name = "nginx_pkgoss",
         build_file_content = _PKGOSS_BUILD_FILE.format(nginx = nginx) +
                              _PKGOSS_BUILD_FILE_TAIL,
-        commit = "908c0e6cd38e1abdaa0af8c2c8969a96b5a67fde",  # nginx-1.13.9
+        commit = "7a50651b4ca9dacc720b1c8f17d2dc31f12c9ff7",  # nginx-1.13.10
         remote = "https://nginx.googlesource.com/nginx-pkgoss",
     )
 
diff --git a/contrib/vim/syntax/nginx.vim b/contrib/vim/syntax/nginx.vim
index 0a21372..075b19a 100644
--- a/contrib/vim/syntax/nginx.vim
+++ b/contrib/vim/syntax/nginx.vim
@@ -241,6 +241,32 @@
 syn keyword ngxDirective contained geoip_proxy
 syn keyword ngxDirective contained geoip_proxy_recursive
 syn keyword ngxDirective contained google_perftools_profiles
+syn keyword ngxDirective contained grpc_bind
+syn keyword ngxDirective contained grpc_buffer_size
+syn keyword ngxDirective contained grpc_connect_timeout
+syn keyword ngxDirective contained grpc_hide_header
+syn keyword ngxDirective contained grpc_ignore_headers
+syn keyword ngxDirective contained grpc_intercept_errors
+syn keyword ngxDirective contained grpc_next_upstream
+syn keyword ngxDirective contained grpc_next_upstream_timeout
+syn keyword ngxDirective contained grpc_next_upstream_tries
+syn keyword ngxDirective contained grpc_pass
+syn keyword ngxDirective contained grpc_pass_header
+syn keyword ngxDirective contained grpc_read_timeout
+syn keyword ngxDirective contained grpc_send_timeout
+syn keyword ngxDirective contained grpc_set_header
+syn keyword ngxDirective contained grpc_ssl_certificate
+syn keyword ngxDirective contained grpc_ssl_certificate_key
+syn keyword ngxDirective contained grpc_ssl_ciphers
+syn keyword ngxDirective contained grpc_ssl_crl
+syn keyword ngxDirective contained grpc_ssl_name
+syn keyword ngxDirective contained grpc_ssl_password_file
+syn keyword ngxDirective contained grpc_ssl_protocols
+syn keyword ngxDirective contained grpc_ssl_server_name
+syn keyword ngxDirective contained grpc_ssl_session_reuse
+syn keyword ngxDirective contained grpc_ssl_trusted_certificate
+syn keyword ngxDirective contained grpc_ssl_verify
+syn keyword ngxDirective contained grpc_ssl_verify_depth
 syn keyword ngxDirective contained gunzip
 syn keyword ngxDirective contained gunzip_buffers
 syn keyword ngxDirective contained gzip
@@ -268,11 +294,14 @@
 syn keyword ngxDirective contained http2_body_preread_size
 syn keyword ngxDirective contained http2_chunk_size
 syn keyword ngxDirective contained http2_idle_timeout
+syn keyword ngxDirective contained http2_max_concurrent_pushes
 syn keyword ngxDirective contained http2_max_concurrent_streams
 syn keyword ngxDirective contained http2_max_field_size
 syn keyword ngxDirective contained http2_max_header_size
 syn keyword ngxDirective contained http2_max_requests
 syn keyword ngxDirective contained http2_pool_size
+syn keyword ngxDirective contained http2_push
+syn keyword ngxDirective contained http2_push_preload
 syn keyword ngxDirective contained http2_recv_buffer_size
 syn keyword ngxDirective contained http2_recv_timeout
 syn keyword ngxDirective contained http2_streams_index_size
@@ -574,6 +603,7 @@
 syn keyword ngxDirective contained sub_filter_last_modified
 syn keyword ngxDirective contained sub_filter_once
 syn keyword ngxDirective contained sub_filter_types
+syn keyword ngxDirective contained subrequest_output_buffer_size
 syn keyword ngxDirective contained tcp_nodelay
 syn keyword ngxDirective contained tcp_nopush
 syn keyword ngxDirective contained thread_pool
@@ -1323,11 +1353,8 @@
 
 " Phusion Passenger
 " https://www.phusionpassenger.com/library/config/nginx/reference/
-syn keyword ngxDirectiveThirdParty contained disable_security_update_check
 syn keyword ngxDirectiveThirdParty contained passenger_abort_on_startup_error
 syn keyword ngxDirectiveThirdParty contained passenger_abort_websockets_on_process_shutdown
-syn keyword ngxDirectiveThirdParty contained passenger_analytics_log_group
-syn keyword ngxDirectiveThirdParty contained passenger_analytics_log_user
 syn keyword ngxDirectiveThirdParty contained passenger_app_env
 syn keyword ngxDirectiveThirdParty contained passenger_app_file_descriptor_ulimit
 syn keyword ngxDirectiveThirdParty contained passenger_app_group_name
@@ -1369,6 +1396,7 @@
 syn keyword ngxDirectiveThirdParty contained passenger_max_pool_size
 syn keyword ngxDirectiveThirdParty contained passenger_max_preloader_idle_time
 syn keyword ngxDirectiveThirdParty contained passenger_max_request_queue_size
+syn keyword ngxDirectiveThirdParty contained passenger_max_request_queue_time
 syn keyword ngxDirectiveThirdParty contained passenger_max_request_time
 syn keyword ngxDirectiveThirdParty contained passenger_max_requests
 syn keyword ngxDirectiveThirdParty contained passenger_memory_limit
@@ -1402,21 +1430,22 @@
 syn keyword ngxDirectiveThirdParty contained passenger_user
 syn keyword ngxDirectiveThirdParty contained passenger_user_switching
 syn keyword ngxDirectiveThirdParty contained passenger_vary_turbocache_by_cookie
-syn keyword ngxDirectiveThirdParty contained rack_env
-syn keyword ngxDirectiveThirdParty contained rails_app_spawner_idle_time
-syn keyword ngxDirectiveThirdParty contained rails_env
-syn keyword ngxDirectiveThirdParty contained security_update_check_proxy
-syn keyword ngxDirectiveThirdParty contained union_station_filter
-syn keyword ngxDirectiveThirdParty contained union_station_gateway_address
-syn keyword ngxDirectiveThirdParty contained union_station_gateway_cert
-syn keyword ngxDirectiveThirdParty contained union_station_gateway_port
-syn keyword ngxDirectiveThirdParty contained union_station_key
-syn keyword ngxDirectiveThirdParty contained union_station_proxy_address
-syn keyword ngxDirectiveThirdParty contained union_station_support
+syn keyword ngxDirectiveThirdPartyDeprecated contained passenger_analytics_log_group
+syn keyword ngxDirectiveThirdPartyDeprecated contained passenger_analytics_log_user
 syn keyword ngxDirectiveThirdPartyDeprecated contained passenger_debug_log_file
 syn keyword ngxDirectiveThirdPartyDeprecated contained passenger_use_global_queue
+syn keyword ngxDirectiveThirdPartyDeprecated contained rack_env
+syn keyword ngxDirectiveThirdPartyDeprecated contained rails_app_spawner_idle_time
+syn keyword ngxDirectiveThirdPartyDeprecated contained rails_env
 syn keyword ngxDirectiveThirdPartyDeprecated contained rails_framework_spawner_idle_time
 syn keyword ngxDirectiveThirdPartyDeprecated contained rails_spawn_method
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_filter
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_gateway_address
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_gateway_cert
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_gateway_port
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_key
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_proxy_address
+syn keyword ngxDirectiveThirdPartyDeprecated contained union_station_support
 
 " ngx_postgres is an upstream module that allows nginx to communicate directly with PostgreSQL database
 " https://github.com/FRiCKLE/ngx_postgres
@@ -2028,6 +2057,7 @@
 syn keyword ngxDirectiveThirdParty contained selective_cache_purge_query
 syn keyword ngxDirectiveThirdParty contained selective_cache_purge_redis_database
 syn keyword ngxDirectiveThirdParty contained selective_cache_purge_redis_host
+syn keyword ngxDirectiveThirdParty contained selective_cache_purge_redis_password
 syn keyword ngxDirectiveThirdParty contained selective_cache_purge_redis_port
 syn keyword ngxDirectiveThirdParty contained selective_cache_purge_redis_unix_socket
 
diff --git a/docs/xml/nginx/changes.xml b/docs/xml/nginx/changes.xml
index a58e164..7cb1fcf 100644
--- a/docs/xml/nginx/changes.xml
+++ b/docs/xml/nginx/changes.xml
@@ -5,6 +5,90 @@
 <change_log title="nginx">
 
 
+<changes ver="1.13.10" date="2018-03-20">
+
+<change type="feature">
+<para lang="ru">
+теперь параметр set в SSI-директиве include
+позволяет сохранять в переменную любые ответы;
+максимальный размер ответа задаётся директивой subrequest_output_buffer_size.
+</para>
+<para lang="en">
+the "set" parameter of the "include" SSI directive now allows
+writing arbitrary responses to a variable;
+the "subrequest_output_buffer_size" directive defines maximum response size.
+</para>
+</change>
+
+<change type="feature">
+<para lang="ru">
+теперь nginx использует вызов clock_gettime(CLOCK_MONOTONIC), если он доступен,
+что позволяет избежать некорректного срабатывания таймаутов
+при изменениях системного времени.
+</para>
+<para lang="en">
+now nginx uses clock_gettime(CLOCK_MONOTONIC) if available,
+to avoid timeouts being incorrectly triggered
+on system time changes.
+</para>
+</change>
+
+<change type="feature">
+<para lang="ru">
+параметр "escape=none" директивы log_format.<br/>
+Спасибо Johannes Baiter и Calin Don.
+</para>
+<para lang="en">
+the "escape=none" parameter of the "log_format" directive.<br/>
+Thanks to Johannes Baiter and Calin Don.
+</para>
+</change>
+
+<change type="feature">
+<para lang="ru">
+переменная $ssl_preread_alpn_protocols
+в модуле ngx_stream_ssl_preread_module.
+</para>
+<para lang="en">
+the $ssl_preread_alpn_protocols variable
+in the ngx_stream_ssl_preread_module.
+</para>
+</change>
+
+<change type="feature">
+<para lang="ru">
+модуль ngx_http_grpc_module.
+</para>
+<para lang="en">
+the ngx_http_grpc_module.
+</para>
+</change>
+
+<change type="bugfix">
+<para lang="ru">
+в обработке ошибок выделения памяти в директиве geo.
+</para>
+<para lang="en">
+in memory allocation error handling in the "geo" directive.
+</para>
+</change>
+
+<change type="bugfix">
+<para lang="ru">
+при использовании переменных в директиве auth_basic_user_file
+в лог мог выводиться символ '\0'.<br/>
+Спасибо Вадиму Филимонову.
+</para>
+<para lang="en">
+when using variables in the "auth_basic_user_file" directive
+a null character might appear in logs.<br/>
+Thanks to Vadim Filimonov.
+</para>
+</change>
+
+</changes>
+
+
 <changes ver="1.13.9" date="2018-02-20">
 
 <change type="feature">
diff --git a/src/core/nginx.h b/src/core/nginx.h
index df8fd80..b6a45db 100644
--- a/src/core/nginx.h
+++ b/src/core/nginx.h
@@ -13,8 +13,8 @@
 #define NGINX_NAME         "nginx"
 #endif
 
-#define nginx_version      1013009
-#define NGINX_VERSION      "1.13.9"
+#define nginx_version      1013010
+#define NGINX_VERSION      "1.13.10"
 #define NGINX_VER          NGINX_NAME "/" NGINX_VERSION
 
 #ifdef NGX_BUILD
diff --git a/src/core/ngx_times.c b/src/core/ngx_times.c
index d8818ab..ff81b09 100644
--- a/src/core/ngx_times.c
+++ b/src/core/ngx_times.c
@@ -9,6 +9,9 @@
 #include <ngx_core.h>
 
 
+static ngx_msec_t ngx_monotonic_time(time_t sec, ngx_uint_t msec);
+
+
 /*
  * The time may be updated by signal handler or by several threads.
  * The time update operations are rare and require to hold the ngx_time_lock.
@@ -93,7 +96,7 @@
     sec = tv.tv_sec;
     msec = tv.tv_usec / 1000;
 
-    ngx_current_msec = (ngx_msec_t) sec * 1000 + msec;
+    ngx_current_msec = ngx_monotonic_time(sec, msec);
 
     tp = &cached_time[slot];
 
@@ -189,6 +192,31 @@
 }
 
 
+static ngx_msec_t
+ngx_monotonic_time(time_t sec, ngx_uint_t msec)
+{
+#if (NGX_HAVE_CLOCK_MONOTONIC)
+    struct timespec  ts;
+
+#if defined(CLOCK_MONOTONIC_FAST)
+    clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
+
+#elif defined(CLOCK_MONOTONIC_COARSE)
+    clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);
+
+#else
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+#endif
+
+    sec = ts.tv_sec;
+    msec = ts.tv_nsec / 1000000;
+
+#endif
+
+    return (ngx_msec_t) sec * 1000 + msec;
+}
+
+
 #if !(NGX_WIN32)
 
 void
diff --git a/src/event/ngx_event_connect.c b/src/event/ngx_event_connect.c
index c5bb806..e7f28c9 100644
--- a/src/event/ngx_event_connect.c
+++ b/src/event/ngx_event_connect.c
@@ -388,7 +388,16 @@
             return NGX_ERROR;
         }
 
+#else
+
+        ngx_log_error(NGX_LOG_ALERT, pc->log, 0,
+                      "could not enable transparent proxying for IPv6 "
+                      "on this platform");
+
+        return NGX_ERROR;
+
 #endif
+
         break;
 
 #endif /* NGX_HAVE_INET6 */
diff --git a/src/http/modules/ngx_http_auth_basic_module.c b/src/http/modules/ngx_http_auth_basic_module.c
index 2f345b6..a6f9ec4 100644
--- a/src/http/modules/ngx_http_auth_basic_module.c
+++ b/src/http/modules/ngx_http_auth_basic_module.c
@@ -266,8 +266,8 @@
     }
 
     ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                  "user \"%V\" was not found in \"%V\"",
-                  &r->headers_in.user, &user_file);
+                  "user \"%V\" was not found in \"%s\"",
+                  &r->headers_in.user, user_file.data);
 
     return ngx_http_auth_basic_set_realm(r, &realm);
 }
diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 7ee515f..bc43f53 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -2512,36 +2512,6 @@
         break;
     }
 
-    /* provide continuous buffer for subrequests in memory */
-
-    if (r->subrequest_in_memory) {
-
-        cl = u->out_bufs;
-
-        if (cl) {
-            buf->pos = cl->buf->pos;
-        }
-
-        buf->last = buf->pos;
-
-        for (cl = u->out_bufs; cl; cl = cl->next) {
-            ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                           "http fastcgi in memory %p-%p %O",
-                           cl->buf->pos, cl->buf->last, ngx_buf_size(cl->buf));
-
-            if (buf->last == cl->buf->pos) {
-                buf->last = cl->buf->last;
-                continue;
-            }
-
-            buf->last = ngx_movemem(buf->last, cl->buf->pos,
-                                    cl->buf->last - cl->buf->pos);
-
-            cl->buf->pos = buf->last - (cl->buf->last - cl->buf->pos);
-            cl->buf->last = buf->last;
-        }
-    }
-
     return NGX_OK;
 }
 
@@ -2736,8 +2706,6 @@
      *     conf->upstream.cache_methods = 0;
      *     conf->upstream.temp_path = NULL;
      *     conf->upstream.hide_headers_hash = { NULL, 0 };
-     *     conf->upstream.uri = { 0, NULL };
-     *     conf->upstream.location = NULL;
      *     conf->upstream.store_lengths = NULL;
      *     conf->upstream.store_values = NULL;
      *
@@ -2789,10 +2757,10 @@
 
     conf->upstream.intercept_errors = NGX_CONF_UNSET;
 
-    /* the hardcoded values */
+    /* "fastcgi_cyclic_temp_file" is disabled */
     conf->upstream.cyclic_temp_file = 0;
+
     conf->upstream.change_buffering = 1;
-    conf->upstream.pass_trailers = 0;
 
     conf->catch_stderr = NGX_CONF_UNSET_PTR;
 
diff --git a/src/http/modules/ngx_http_geo_module.c b/src/http/modules/ngx_http_geo_module.c
index 8262c9d..c11bafa 100644
--- a/src/http/modules/ngx_http_geo_module.c
+++ b/src/http/modules/ngx_http_geo_module.c
@@ -439,6 +439,7 @@
 
     ctx.temp_pool = ngx_create_pool(NGX_DEFAULT_POOL_SIZE, cf->log);
     if (ctx.temp_pool == NULL) {
+        ngx_destroy_pool(pool);
         return NGX_CONF_ERROR;
     }
 
@@ -460,6 +461,10 @@
 
     *cf = save;
 
+    if (rv != NGX_CONF_OK) {
+        goto failed;
+    }
+
     geo->proxies = ctx.proxies;
     geo->proxy_recursive = ctx.proxy_recursive;
 
@@ -482,7 +487,7 @@
 
                 ctx.high.low[i] = ngx_palloc(cf->pool, len + sizeof(void *));
                 if (ctx.high.low[i] == NULL) {
-                    return NGX_CONF_ERROR;
+                    goto failed;
                 }
 
                 ngx_memcpy(ctx.high.low[i], a->elts, len);
@@ -508,14 +513,11 @@
         var->get_handler = ngx_http_geo_range_variable;
         var->data = (uintptr_t) geo;
 
-        ngx_destroy_pool(ctx.temp_pool);
-        ngx_destroy_pool(pool);
-
     } else {
         if (ctx.tree == NULL) {
             ctx.tree = ngx_radix_tree_create(cf->pool, -1);
             if (ctx.tree == NULL) {
-                return NGX_CONF_ERROR;
+                goto failed;
             }
         }
 
@@ -525,7 +527,7 @@
         if (ctx.tree6 == NULL) {
             ctx.tree6 = ngx_radix_tree_create(cf->pool, -1);
             if (ctx.tree6 == NULL) {
-                return NGX_CONF_ERROR;
+                goto failed;
             }
         }
 
@@ -535,14 +537,11 @@
         var->get_handler = ngx_http_geo_cidr_variable;
         var->data = (uintptr_t) geo;
 
-        ngx_destroy_pool(ctx.temp_pool);
-        ngx_destroy_pool(pool);
-
         if (ngx_radix32tree_insert(ctx.tree, 0, 0,
                                    (uintptr_t) &ngx_http_variable_null_value)
             == NGX_ERROR)
         {
-            return NGX_CONF_ERROR;
+            goto failed;
         }
 
         /* NGX_BUSY is okay (default was set explicitly) */
@@ -552,12 +551,22 @@
                                     (uintptr_t) &ngx_http_variable_null_value)
             == NGX_ERROR)
         {
-            return NGX_CONF_ERROR;
+            goto failed;
         }
 #endif
     }
 
-    return rv;
+    ngx_destroy_pool(ctx.temp_pool);
+    ngx_destroy_pool(pool);
+
+    return NGX_CONF_OK;
+
+failed:
+
+    ngx_destroy_pool(ctx.temp_pool);
+    ngx_destroy_pool(pool);
+
+    return NGX_CONF_ERROR;
 }
 
 
diff --git a/src/http/modules/ngx_http_grpc_module.c b/src/http/modules/ngx_http_grpc_module.c
new file mode 100644
index 0000000..b6be9b8
--- /dev/null
+++ b/src/http/modules/ngx_http_grpc_module.c
@@ -0,0 +1,4640 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+typedef struct {
+    ngx_array_t               *flushes;
+    ngx_array_t               *lengths;
+    ngx_array_t               *values;
+    ngx_hash_t                 hash;
+} ngx_http_grpc_headers_t;
+
+
+typedef struct {
+    ngx_http_upstream_conf_t   upstream;
+
+    ngx_http_grpc_headers_t    headers;
+    ngx_array_t               *headers_source;
+
+    ngx_str_t                  host;
+    ngx_uint_t                 host_set;
+
+#if (NGX_HTTP_SSL)
+    ngx_uint_t                 ssl;
+    ngx_uint_t                 ssl_protocols;
+    ngx_str_t                  ssl_ciphers;
+    ngx_uint_t                 ssl_verify_depth;
+    ngx_str_t                  ssl_trusted_certificate;
+    ngx_str_t                  ssl_crl;
+    ngx_str_t                  ssl_certificate;
+    ngx_str_t                  ssl_certificate_key;
+    ngx_array_t               *ssl_passwords;
+#endif
+} ngx_http_grpc_loc_conf_t;
+
+
+typedef enum {
+    ngx_http_grpc_st_start = 0,
+    ngx_http_grpc_st_length_2,
+    ngx_http_grpc_st_length_3,
+    ngx_http_grpc_st_type,
+    ngx_http_grpc_st_flags,
+    ngx_http_grpc_st_stream_id,
+    ngx_http_grpc_st_stream_id_2,
+    ngx_http_grpc_st_stream_id_3,
+    ngx_http_grpc_st_stream_id_4,
+    ngx_http_grpc_st_payload,
+    ngx_http_grpc_st_padding
+} ngx_http_grpc_state_e;
+
+
+typedef struct {
+    size_t                     init_window;
+    size_t                     send_window;
+    size_t                     recv_window;
+    ngx_uint_t                 last_stream_id;
+} ngx_http_grpc_conn_t;
+
+
+typedef struct {
+    ngx_http_grpc_state_e      state;
+    ngx_uint_t                 frame_state;
+    ngx_uint_t                 fragment_state;
+
+    ngx_chain_t               *in;
+    ngx_chain_t               *out;
+    ngx_chain_t               *free;
+    ngx_chain_t               *busy;
+
+    ngx_http_grpc_conn_t      *connection;
+
+    ngx_uint_t                 id;
+
+    ssize_t                    send_window;
+    size_t                     recv_window;
+
+    size_t                     rest;
+    ngx_uint_t                 stream_id;
+    u_char                     type;
+    u_char                     flags;
+    u_char                     padding;
+
+    ngx_uint_t                 error;
+    ngx_uint_t                 window_update;
+
+    ngx_uint_t                 setting_id;
+    ngx_uint_t                 setting_value;
+
+    u_char                     ping_data[8];
+
+    ngx_uint_t                 index;
+    ngx_str_t                  name;
+    ngx_str_t                  value;
+
+    u_char                    *field_end;
+    size_t                     field_length;
+    size_t                     field_rest;
+    u_char                     field_state;
+
+    unsigned                   literal:1;
+    unsigned                   field_huffman:1;
+
+    unsigned                   header_sent:1;
+    unsigned                   output_closed:1;
+    unsigned                   parsing_headers:1;
+    unsigned                   end_stream:1;
+    unsigned                   status:1;
+
+    ngx_http_request_t        *request;
+} ngx_http_grpc_ctx_t;
+
+
+typedef struct {
+    u_char                     length_0;
+    u_char                     length_1;
+    u_char                     length_2;
+    u_char                     type;
+    u_char                     flags;
+    u_char                     stream_id_0;
+    u_char                     stream_id_1;
+    u_char                     stream_id_2;
+    u_char                     stream_id_3;
+} ngx_http_grpc_frame_t;
+
+
+static ngx_int_t ngx_http_grpc_create_request(ngx_http_request_t *r);
+static ngx_int_t ngx_http_grpc_reinit_request(ngx_http_request_t *r);
+static ngx_int_t ngx_http_grpc_body_output_filter(void *data, ngx_chain_t *in);
+static ngx_int_t ngx_http_grpc_process_header(ngx_http_request_t *r);
+static ngx_int_t ngx_http_grpc_filter_init(void *data);
+static ngx_int_t ngx_http_grpc_filter(void *data, ssize_t bytes);
+
+static ngx_int_t ngx_http_grpc_parse_frame(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_header(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_fragment(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_validate_header_name(ngx_http_request_t *r,
+    ngx_str_t *s);
+static ngx_int_t ngx_http_grpc_validate_header_value(ngx_http_request_t *r,
+    ngx_str_t *s);
+static ngx_int_t ngx_http_grpc_parse_rst_stream(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_goaway(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_window_update(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_settings(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+static ngx_int_t ngx_http_grpc_parse_ping(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b);
+
+static ngx_int_t ngx_http_grpc_send_settings_ack(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx);
+static ngx_int_t ngx_http_grpc_send_ping_ack(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx);
+static ngx_int_t ngx_http_grpc_send_window_update(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx);
+
+static ngx_chain_t *ngx_http_grpc_get_buf(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx);
+static ngx_http_grpc_ctx_t *ngx_http_grpc_get_ctx(ngx_http_request_t *r);
+static ngx_int_t ngx_http_grpc_get_connection_data(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_peer_connection_t *pc);
+static void ngx_http_grpc_cleanup(void *data);
+
+static void ngx_http_grpc_abort_request(ngx_http_request_t *r);
+static void ngx_http_grpc_finalize_request(ngx_http_request_t *r,
+    ngx_int_t rc);
+
+static ngx_int_t ngx_http_grpc_internal_trailers_variable(
+    ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data);
+
+static ngx_int_t ngx_http_grpc_add_variables(ngx_conf_t *cf);
+static void *ngx_http_grpc_create_loc_conf(ngx_conf_t *cf);
+static char *ngx_http_grpc_merge_loc_conf(ngx_conf_t *cf,
+    void *parent, void *child);
+static ngx_int_t ngx_http_grpc_init_headers(ngx_conf_t *cf,
+    ngx_http_grpc_loc_conf_t *conf, ngx_http_grpc_headers_t *headers,
+    ngx_keyval_t *default_headers);
+
+static char *ngx_http_grpc_pass(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+
+#if (NGX_HTTP_SSL)
+static char *ngx_http_grpc_ssl_password_file(ngx_conf_t *cf,
+    ngx_command_t *cmd, void *conf);
+static ngx_int_t ngx_http_grpc_set_ssl(ngx_conf_t *cf,
+    ngx_http_grpc_loc_conf_t *glcf);
+#endif
+
+
+static ngx_conf_bitmask_t  ngx_http_grpc_next_upstream_masks[] = {
+    { ngx_string("error"), NGX_HTTP_UPSTREAM_FT_ERROR },
+    { ngx_string("timeout"), NGX_HTTP_UPSTREAM_FT_TIMEOUT },
+    { ngx_string("invalid_header"), NGX_HTTP_UPSTREAM_FT_INVALID_HEADER },
+    { ngx_string("non_idempotent"), NGX_HTTP_UPSTREAM_FT_NON_IDEMPOTENT },
+    { ngx_string("http_500"), NGX_HTTP_UPSTREAM_FT_HTTP_500 },
+    { ngx_string("http_502"), NGX_HTTP_UPSTREAM_FT_HTTP_502 },
+    { ngx_string("http_503"), NGX_HTTP_UPSTREAM_FT_HTTP_503 },
+    { ngx_string("http_504"), NGX_HTTP_UPSTREAM_FT_HTTP_504 },
+    { ngx_string("http_403"), NGX_HTTP_UPSTREAM_FT_HTTP_403 },
+    { ngx_string("http_404"), NGX_HTTP_UPSTREAM_FT_HTTP_404 },
+    { ngx_string("http_429"), NGX_HTTP_UPSTREAM_FT_HTTP_429 },
+    { ngx_string("off"), NGX_HTTP_UPSTREAM_FT_OFF },
+    { ngx_null_string, 0 }
+};
+
+
+#if (NGX_HTTP_SSL)
+
+static ngx_conf_bitmask_t  ngx_http_grpc_ssl_protocols[] = {
+    { ngx_string("SSLv2"), NGX_SSL_SSLv2 },
+    { ngx_string("SSLv3"), NGX_SSL_SSLv3 },
+    { ngx_string("TLSv1"), NGX_SSL_TLSv1 },
+    { ngx_string("TLSv1.1"), NGX_SSL_TLSv1_1 },
+    { ngx_string("TLSv1.2"), NGX_SSL_TLSv1_2 },
+    { ngx_string("TLSv1.3"), NGX_SSL_TLSv1_3 },
+    { ngx_null_string, 0 }
+};
+
+#endif
+
+
+static ngx_command_t  ngx_http_grpc_commands[] = {
+
+    { ngx_string("grpc_pass"),
+      NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF|NGX_CONF_TAKE1,
+      ngx_http_grpc_pass,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      0,
+      NULL },
+
+    { ngx_string("grpc_bind"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
+      ngx_http_upstream_bind_set_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.local),
+      NULL },
+
+    { ngx_string("grpc_connect_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.connect_timeout),
+      NULL },
+
+    { ngx_string("grpc_send_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.send_timeout),
+      NULL },
+
+    { ngx_string("grpc_intercept_errors"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.intercept_errors),
+      NULL },
+
+    { ngx_string("grpc_buffer_size"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.buffer_size),
+      NULL },
+
+    { ngx_string("grpc_read_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.read_timeout),
+      NULL },
+
+    { ngx_string("grpc_next_upstream"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
+      ngx_conf_set_bitmask_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.next_upstream),
+      &ngx_http_grpc_next_upstream_masks },
+
+    { ngx_string("grpc_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("grpc_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
+    { ngx_string("grpc_set_header"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
+      ngx_conf_set_keyval_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, headers_source),
+      NULL },
+
+    { ngx_string("grpc_pass_header"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_array_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.pass_headers),
+      NULL },
+
+    { ngx_string("grpc_hide_header"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_array_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.hide_headers),
+      NULL },
+
+    { ngx_string("grpc_ignore_headers"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
+      ngx_conf_set_bitmask_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.ignore_headers),
+      &ngx_http_upstream_ignore_headers_masks },
+
+#if (NGX_HTTP_SSL)
+
+    { ngx_string("grpc_ssl_session_reuse"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.ssl_session_reuse),
+      NULL },
+
+    { ngx_string("grpc_ssl_protocols"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
+      ngx_conf_set_bitmask_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_protocols),
+      &ngx_http_grpc_ssl_protocols },
+
+    { ngx_string("grpc_ssl_ciphers"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_ciphers),
+      NULL },
+
+    { ngx_string("grpc_ssl_name"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_http_set_complex_value_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.ssl_name),
+      NULL },
+
+    { ngx_string("grpc_ssl_server_name"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.ssl_server_name),
+      NULL },
+
+    { ngx_string("grpc_ssl_verify"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, upstream.ssl_verify),
+      NULL },
+
+    { ngx_string("grpc_ssl_verify_depth"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_verify_depth),
+      NULL },
+
+    { ngx_string("grpc_ssl_trusted_certificate"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_trusted_certificate),
+      NULL },
+
+    { ngx_string("grpc_ssl_crl"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_crl),
+      NULL },
+
+    { ngx_string("grpc_ssl_certificate"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_certificate),
+      NULL },
+
+    { ngx_string("grpc_ssl_certificate_key"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_grpc_loc_conf_t, ssl_certificate_key),
+      NULL },
+
+    { ngx_string("grpc_ssl_password_file"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_http_grpc_ssl_password_file,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      0,
+      NULL },
+
+#endif
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_grpc_module_ctx = {
+    ngx_http_grpc_add_variables,           /* preconfiguration */
+    NULL,                                  /* postconfiguration */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    NULL,                                  /* create server configuration */
+    NULL,                                  /* merge server configuration */
+
+    ngx_http_grpc_create_loc_conf,         /* create location configuration */
+    ngx_http_grpc_merge_loc_conf           /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_grpc_module = {
+    NGX_MODULE_V1,
+    &ngx_http_grpc_module_ctx,             /* module context */
+    ngx_http_grpc_commands,                /* module directives */
+    NGX_HTTP_MODULE,                       /* module type */
+    NULL,                                  /* init master */
+    NULL,                                  /* init module */
+    NULL,                                  /* init process */
+    NULL,                                  /* init thread */
+    NULL,                                  /* exit thread */
+    NULL,                                  /* exit process */
+    NULL,                                  /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static u_char  ngx_http_grpc_connection_start[] =
+    "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"         /* connection preface */
+
+    "\x00\x00\x12\x04\x00\x00\x00\x00\x00"     /* settings frame */
+    "\x00\x01\x00\x00\x00\x00"                 /* header table size */
+    "\x00\x02\x00\x00\x00\x00"                 /* disable push */
+    "\x00\x04\x7f\xff\xff\xff"                 /* initial window */
+
+    "\x00\x00\x04\x08\x00\x00\x00\x00\x00"     /* window update frame */
+    "\x7f\xff\x00\x00";
+
+
+static ngx_keyval_t  ngx_http_grpc_headers[] = {
+    { ngx_string("Content-Length"), ngx_string("$content_length") },
+    { ngx_string("TE"), ngx_string("$grpc_internal_trailers") },
+    { ngx_string("Host"), ngx_string("") },
+    { ngx_string("Connection"), ngx_string("") },
+    { ngx_string("Transfer-Encoding"), ngx_string("") },
+    { ngx_string("Keep-Alive"), ngx_string("") },
+    { ngx_string("Expect"), ngx_string("") },
+    { ngx_string("Upgrade"), ngx_string("") },
+    { ngx_null_string, ngx_null_string }
+};
+
+
+static ngx_str_t  ngx_http_grpc_hide_headers[] = {
+    ngx_string("Date"),
+    ngx_string("Server"),
+    ngx_string("X-Accel-Expires"),
+    ngx_string("X-Accel-Redirect"),
+    ngx_string("X-Accel-Limit-Rate"),
+    ngx_string("X-Accel-Buffering"),
+    ngx_string("X-Accel-Charset"),
+    ngx_null_string
+};
+
+
+static ngx_http_variable_t  ngx_http_grpc_vars[] = {
+
+    { ngx_string("grpc_internal_trailers"), NULL,
+      ngx_http_grpc_internal_trailers_variable, 0,
+      NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0 },
+
+      ngx_http_null_variable
+};
+
+
+static ngx_int_t
+ngx_http_grpc_handler(ngx_http_request_t *r)
+{
+    ngx_int_t                  rc;
+    ngx_http_upstream_t       *u;
+    ngx_http_grpc_ctx_t       *ctx;
+    ngx_http_grpc_loc_conf_t  *glcf;
+
+    if (ngx_http_upstream_create(r) != NGX_OK) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    glcf = ngx_http_get_module_loc_conf(r, ngx_http_grpc_module);
+
+    u = r->upstream;
+
+#if (NGX_HTTP_SSL)
+    u->ssl = (glcf->upstream.ssl != NULL);
+
+    if (u->ssl) {
+        ngx_str_set(&u->schema, "grpcs://");
+
+    } else {
+        ngx_str_set(&u->schema, "grpc://");
+    }
+#else
+    ngx_str_set(&u->schema, "grpc://");
+#endif
+
+    u->output.tag = (ngx_buf_tag_t) &ngx_http_grpc_module;
+
+    u->conf = &glcf->upstream;
+
+    u->create_request = ngx_http_grpc_create_request;
+    u->reinit_request = ngx_http_grpc_reinit_request;
+    u->process_header = ngx_http_grpc_process_header;
+    u->abort_request = ngx_http_grpc_abort_request;
+    u->finalize_request = ngx_http_grpc_finalize_request;
+
+    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_grpc_ctx_t));
+    if (ctx == NULL) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    ctx->request = r;
+
+    ngx_http_set_ctx(r, ctx, ngx_http_grpc_module);
+
+    u->input_filter_init = ngx_http_grpc_filter_init;
+    u->input_filter = ngx_http_grpc_filter;
+    u->input_filter_ctx = ctx;
+
+    r->request_body_no_buffering = 1;
+
+    rc = ngx_http_read_client_request_body(r, ngx_http_upstream_init);
+
+    if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
+        return rc;
+    }
+
+    return NGX_DONE;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_create_request(ngx_http_request_t *r)
+{
+    u_char                       *p, *tmp, *key_tmp, *val_tmp, *headers_frame;
+    size_t                        len, tmp_len, key_len, val_len, uri_len;
+    uintptr_t                     escape;
+    ngx_buf_t                    *b;
+    ngx_uint_t                    i, next;
+    ngx_chain_t                  *cl, *body;
+    ngx_list_part_t              *part;
+    ngx_table_elt_t              *header;
+    ngx_http_upstream_t          *u;
+    ngx_http_grpc_frame_t        *f;
+    ngx_http_script_code_pt       code;
+    ngx_http_grpc_loc_conf_t     *glcf;
+    ngx_http_script_engine_t      e, le;
+    ngx_http_script_len_code_pt   lcode;
+
+    u = r->upstream;
+
+    glcf = ngx_http_get_module_loc_conf(r, ngx_http_grpc_module);
+
+    len = sizeof(ngx_http_grpc_connection_start) - 1
+          + sizeof(ngx_http_grpc_frame_t);             /* headers frame */
+
+    /* :method header */
+
+    if (r->method == NGX_HTTP_GET || r->method == NGX_HTTP_POST) {
+        len += 1;
+        tmp_len = 0;
+
+    } else {
+        len += 1 + NGX_HTTP_V2_INT_OCTETS + r->method_name.len;
+        tmp_len = r->method_name.len;
+    }
+
+    /* :scheme header */
+
+    len += 1;
+
+    /* :path header */
+
+    if (r->valid_unparsed_uri) {
+        escape = 0;
+        uri_len = r->unparsed_uri.len;
+
+    } else {
+        escape = 2 * ngx_escape_uri(NULL, r->uri.data, r->uri.len,
+                                    NGX_ESCAPE_URI);
+        uri_len = r->uri.len + escape + sizeof("?") - 1 + r->args.len;
+    }
+
+    len += 1 + NGX_HTTP_V2_INT_OCTETS + uri_len;
+
+    if (tmp_len < uri_len) {
+        tmp_len = uri_len;
+    }
+
+    /* :authority header */
+
+    if (!glcf->host_set) {
+        len += 1 + NGX_HTTP_V2_INT_OCTETS + glcf->host.len;
+
+        if (tmp_len < glcf->host.len) {
+            tmp_len = glcf->host.len;
+        }
+    }
+
+    /* other headers */
+
+    ngx_http_script_flush_no_cacheable_variables(r, glcf->headers.flushes);
+    ngx_memzero(&le, sizeof(ngx_http_script_engine_t));
+
+    le.ip = glcf->headers.lengths->elts;
+    le.request = r;
+    le.flushed = 1;
+
+    while (*(uintptr_t *) le.ip) {
+
+        lcode = *(ngx_http_script_len_code_pt *) le.ip;
+        key_len = lcode(&le);
+
+        for (val_len = 0; *(uintptr_t *) le.ip; val_len += lcode(&le)) {
+            lcode = *(ngx_http_script_len_code_pt *) le.ip;
+        }
+        le.ip += sizeof(uintptr_t);
+
+        if (val_len == 0) {
+            continue;
+        }
+
+        len += 1 + NGX_HTTP_V2_INT_OCTETS + key_len
+                 + NGX_HTTP_V2_INT_OCTETS + val_len;
+
+        if (tmp_len < key_len) {
+            tmp_len = key_len;
+        }
+
+        if (tmp_len < val_len) {
+            tmp_len = val_len;
+        }
+    }
+
+    if (glcf->upstream.pass_request_headers) {
+        part = &r->headers_in.headers.part;
+        header = part->elts;
+
+        for (i = 0; /* void */; i++) {
+
+            if (i >= part->nelts) {
+                if (part->next == NULL) {
+                    break;
+                }
+
+                part = part->next;
+                header = part->elts;
+                i = 0;
+            }
+
+            if (ngx_hash_find(&glcf->headers.hash, header[i].hash,
+                              header[i].lowcase_key, header[i].key.len))
+            {
+                continue;
+            }
+
+            len += 1 + NGX_HTTP_V2_INT_OCTETS + header[i].key.len
+                     + NGX_HTTP_V2_INT_OCTETS + header[i].value.len;
+
+            if (tmp_len < header[i].key.len) {
+                tmp_len = header[i].key.len;
+            }
+
+            if (tmp_len < header[i].value.len) {
+                tmp_len = header[i].value.len;
+            }
+        }
+    }
+
+    /* continuation frames */
+
+    len += sizeof(ngx_http_grpc_frame_t)
+           * (len / NGX_HTTP_V2_DEFAULT_FRAME_SIZE);
+
+
+    b = ngx_create_temp_buf(r->pool, len);
+    if (b == NULL) {
+        return NGX_ERROR;
+    }
+
+    cl = ngx_alloc_chain_link(r->pool);
+    if (cl == NULL) {
+        return NGX_ERROR;
+    }
+
+    cl->buf = b;
+    cl->next = NULL;
+
+    tmp = ngx_palloc(r->pool, tmp_len * 3);
+    if (tmp == NULL) {
+        return NGX_ERROR;
+    }
+
+    key_tmp = tmp + tmp_len;
+    val_tmp = tmp + 2 * tmp_len;
+
+    /* connection preface */
+
+    b->last = ngx_copy(b->last, ngx_http_grpc_connection_start,
+                       sizeof(ngx_http_grpc_connection_start) - 1);
+
+    /* headers frame */
+
+    headers_frame = b->last;
+
+    f = (ngx_http_grpc_frame_t *) b->last;
+    b->last += sizeof(ngx_http_grpc_frame_t);
+
+    f->length_0 = 0;
+    f->length_1 = 0;
+    f->length_2 = 0;
+    f->type = NGX_HTTP_V2_HEADERS_FRAME;
+    f->flags = 0;
+    f->stream_id_0 = 0;
+    f->stream_id_1 = 0;
+    f->stream_id_2 = 0;
+    f->stream_id_3 = 1;
+
+    if (r->method == NGX_HTTP_GET) {
+        *b->last++ = ngx_http_v2_indexed(NGX_HTTP_V2_METHOD_GET_INDEX);
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":method: GET\"");
+
+    } else if (r->method == NGX_HTTP_POST) {
+        *b->last++ = ngx_http_v2_indexed(NGX_HTTP_V2_METHOD_POST_INDEX);
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":method: POST\"");
+
+    } else {
+        *b->last++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_METHOD_INDEX);
+        b->last = ngx_http_v2_write_value(b->last, r->method_name.data,
+                                          r->method_name.len, tmp);
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":method: %V\"", &r->method_name);
+    }
+
+#if (NGX_HTTP_SSL)
+    if (glcf->ssl) {
+        *b->last++ = ngx_http_v2_indexed(NGX_HTTP_V2_SCHEME_HTTPS_INDEX);
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":scheme: https\"");
+    } else
+#endif
+    {
+        *b->last++ = ngx_http_v2_indexed(NGX_HTTP_V2_SCHEME_HTTP_INDEX);
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":scheme: http\"");
+    }
+
+    if (r->valid_unparsed_uri) {
+
+        if (r->unparsed_uri.len == 1 && r->unparsed_uri.data[0] == '/') {
+            *b->last++ = ngx_http_v2_indexed(NGX_HTTP_V2_PATH_ROOT_INDEX);
+
+        } else {
+            *b->last++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_PATH_INDEX);
+            b->last = ngx_http_v2_write_value(b->last, r->unparsed_uri.data,
+                                              r->unparsed_uri.len, tmp);
+        }
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":path: %V\"", &r->unparsed_uri);
+
+    } else if (escape || r->args.len > 0) {
+        p = val_tmp;
+
+        if (escape) {
+            p = (u_char *) ngx_escape_uri(p, r->uri.data, r->uri.len,
+                                          NGX_ESCAPE_URI);
+
+        } else {
+            p = ngx_copy(p, r->uri.data, r->uri.len);
+        }
+
+        if (r->args.len > 0) {
+            *p++ = '?';
+            p = ngx_copy(p, r->args.data, r->args.len);
+        }
+
+        *b->last++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_PATH_INDEX);
+        b->last = ngx_http_v2_write_value(b->last, val_tmp, p - val_tmp, tmp);
+
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":path: %*s\"", p - val_tmp, val_tmp);
+
+    } else {
+        *b->last++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_PATH_INDEX);
+        b->last = ngx_http_v2_write_value(b->last, r->uri.data,
+                                          r->uri.len, tmp);
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":path: %V\"", &r->uri);
+    }
+
+    if (!glcf->host_set) {
+        *b->last++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_AUTHORITY_INDEX);
+        b->last = ngx_http_v2_write_value(b->last, glcf->host.data,
+                                          glcf->host.len, tmp);
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: \":authority: %V\"", &glcf->host);
+    }
+
+    ngx_memzero(&e, sizeof(ngx_http_script_engine_t));
+
+    e.ip = glcf->headers.values->elts;
+    e.request = r;
+    e.flushed = 1;
+
+    le.ip = glcf->headers.lengths->elts;
+
+    while (*(uintptr_t *) le.ip) {
+
+        lcode = *(ngx_http_script_len_code_pt *) le.ip;
+        key_len = lcode(&le);
+
+        for (val_len = 0; *(uintptr_t *) le.ip; val_len += lcode(&le)) {
+            lcode = *(ngx_http_script_len_code_pt *) le.ip;
+        }
+        le.ip += sizeof(uintptr_t);
+
+        if (val_len == 0) {
+            e.skip = 1;
+
+            while (*(uintptr_t *) e.ip) {
+                code = *(ngx_http_script_code_pt *) e.ip;
+                code((ngx_http_script_engine_t *) &e);
+            }
+            e.ip += sizeof(uintptr_t);
+
+            e.skip = 0;
+
+            continue;
+        }
+
+        *b->last++ = 0;
+
+        e.pos = key_tmp;
+
+        code = *(ngx_http_script_code_pt *) e.ip;
+        code((ngx_http_script_engine_t *) &e);
+
+        b->last = ngx_http_v2_write_name(b->last, key_tmp, key_len, tmp);
+
+        e.pos = val_tmp;
+
+        while (*(uintptr_t *) e.ip) {
+            code = *(ngx_http_script_code_pt *) e.ip;
+            code((ngx_http_script_engine_t *) &e);
+        }
+        e.ip += sizeof(uintptr_t);
+
+        b->last = ngx_http_v2_write_value(b->last, val_tmp, val_len, tmp);
+
+#if (NGX_DEBUG)
+        if (r->connection->log->log_level & NGX_LOG_DEBUG_HTTP) {
+            ngx_strlow(key_tmp, key_tmp, key_len);
+
+            ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc header: \"%*s: %*s\"",
+                           key_len, key_tmp, val_len, val_tmp);
+        }
+#endif
+    }
+
+    if (glcf->upstream.pass_request_headers) {
+        part = &r->headers_in.headers.part;
+        header = part->elts;
+
+        for (i = 0; /* void */; i++) {
+
+            if (i >= part->nelts) {
+                if (part->next == NULL) {
+                    break;
+                }
+
+                part = part->next;
+                header = part->elts;
+                i = 0;
+            }
+
+            if (ngx_hash_find(&glcf->headers.hash, header[i].hash,
+                              header[i].lowcase_key, header[i].key.len))
+            {
+                continue;
+            }
+
+            *b->last++ = 0;
+
+            b->last = ngx_http_v2_write_name(b->last, header[i].key.data,
+                                             header[i].key.len, tmp);
+
+            b->last = ngx_http_v2_write_value(b->last, header[i].value.data,
+                                              header[i].value.len, tmp);
+
+#if (NGX_DEBUG)
+            if (r->connection->log->log_level & NGX_LOG_DEBUG_HTTP) {
+                ngx_strlow(tmp, header[i].key.data, header[i].key.len);
+
+                ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc header: \"%*s: %V\"",
+                               header[i].key.len, tmp, &header[i].value);
+            }
+#endif
+        }
+    }
+
+    /* update headers frame length */
+
+    len = b->last - headers_frame - sizeof(ngx_http_grpc_frame_t);
+
+    if (len > NGX_HTTP_V2_DEFAULT_FRAME_SIZE) {
+        len = NGX_HTTP_V2_DEFAULT_FRAME_SIZE;
+        next = 1;
+
+    } else {
+        next = 0;
+    }
+
+    f = (ngx_http_grpc_frame_t *) headers_frame;
+
+    f->length_0 = (u_char) ((len >> 16) & 0xff);
+    f->length_1 = (u_char) ((len >> 8) & 0xff);
+    f->length_2 = (u_char) (len & 0xff);
+
+    /* create additional continuation frames */
+
+    p = headers_frame;
+
+    while (next) {
+        p += sizeof(ngx_http_grpc_frame_t) + NGX_HTTP_V2_DEFAULT_FRAME_SIZE;
+        len = b->last - p;
+
+        ngx_memmove(p + sizeof(ngx_http_grpc_frame_t), p, len);
+        b->last += sizeof(ngx_http_grpc_frame_t);
+
+        if (len > NGX_HTTP_V2_DEFAULT_FRAME_SIZE) {
+            len = NGX_HTTP_V2_DEFAULT_FRAME_SIZE;
+            next = 1;
+
+        } else {
+            next = 0;
+        }
+
+        f = (ngx_http_grpc_frame_t *) p;
+
+        f->length_0 = (u_char) ((len >> 16) & 0xff);
+        f->length_1 = (u_char) ((len >> 8) & 0xff);
+        f->length_2 = (u_char) (len & 0xff);
+        f->type = NGX_HTTP_V2_CONTINUATION_FRAME;
+        f->flags = 0;
+        f->stream_id_0 = 0;
+        f->stream_id_1 = 0;
+        f->stream_id_2 = 0;
+        f->stream_id_3 = 1;
+    }
+
+    f->flags |= NGX_HTTP_V2_END_HEADERS_FLAG;
+
+#if (NGX_DEBUG)
+    if (r->connection->log->log_level & NGX_LOG_DEBUG_HTTP) {
+        u_char  buf[512];
+        size_t  n, m;
+
+        n = ngx_min(b->last - b->pos, 256);
+        m = ngx_hex_dump(buf, b->pos, n) - buf;
+
+        ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header: %*s%s, len: %uz",
+                       m, buf, b->last - b->pos > 256 ? "..." : "",
+                       b->last - b->pos);
+    }
+#endif
+
+    if (r->request_body_no_buffering) {
+
+        u->request_bufs = cl;
+
+    } else {
+
+        body = u->request_bufs;
+        u->request_bufs = cl;
+
+        if (body == NULL) {
+            f = (ngx_http_grpc_frame_t *) headers_frame;
+            f->flags |= NGX_HTTP_V2_END_STREAM_FLAG;
+        }
+
+        while (body) {
+            b = ngx_alloc_buf(r->pool);
+            if (b == NULL) {
+                return NGX_ERROR;
+            }
+
+            ngx_memcpy(b, body->buf, sizeof(ngx_buf_t));
+
+            cl->next = ngx_alloc_chain_link(r->pool);
+            if (cl->next == NULL) {
+                return NGX_ERROR;
+            }
+
+            cl = cl->next;
+            cl->buf = b;
+
+            body = body->next;
+        }
+
+        b->last_buf = 1;
+    }
+
+    u->output.output_filter = ngx_http_grpc_body_output_filter;
+    u->output.filter_ctx = r;
+
+    b->flush = 1;
+    cl->next = NULL;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_reinit_request(ngx_http_request_t *r)
+{
+    ngx_http_grpc_ctx_t  *ctx;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_grpc_module);
+
+    if (ctx == NULL) {
+        return NGX_OK;
+    }
+
+    ctx->state = 0;
+    ctx->header_sent = 0;
+    ctx->output_closed = 0;
+    ctx->parsing_headers = 0;
+    ctx->end_stream = 0;
+    ctx->status = 0;
+    ctx->connection = NULL;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_body_output_filter(void *data, ngx_chain_t *in)
+{
+    ngx_http_request_t  *r = data;
+
+    off_t                   file_pos;
+    u_char                 *p, *pos, *start;
+    size_t                  len, limit;
+    ngx_buf_t              *b;
+    ngx_int_t               rc;
+    ngx_uint_t              next, last;
+    ngx_chain_t            *cl, *out, **ll;
+    ngx_http_grpc_ctx_t    *ctx;
+    ngx_http_grpc_frame_t  *f;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc output filter");
+
+    ctx = ngx_http_grpc_get_ctx(r);
+
+    if (ctx == NULL) {
+        return NGX_ERROR;
+    }
+
+    if (in) {
+        if (ngx_chain_add_copy(r->pool, &ctx->in, in) != NGX_OK) {
+            return NGX_ERROR;
+        }
+    }
+
+    out = NULL;
+    ll = &out;
+
+    if (!ctx->header_sent) {
+        /* first buffer contains headers */
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc output header");
+
+        ctx->header_sent = 1;
+
+        if (ctx->id != 1) {
+            /*
+             * keepalive connection: skip connection preface,
+             * update stream identifiers
+             */
+
+            b = ctx->in->buf;
+            b->pos += sizeof(ngx_http_grpc_connection_start) - 1;
+
+            p = b->pos;
+
+            while (p < b->last) {
+                f = (ngx_http_grpc_frame_t *) p;
+                p += sizeof(ngx_http_grpc_frame_t);
+
+                f->stream_id_0 = (u_char) ((ctx->id >> 24) & 0xff);
+                f->stream_id_1 = (u_char) ((ctx->id >> 16) & 0xff);
+                f->stream_id_2 = (u_char) ((ctx->id >> 8) & 0xff);
+                f->stream_id_3 = (u_char) (ctx->id & 0xff);
+
+                p += (f->length_0 << 16) + (f->length_1 << 8) + f->length_2;
+            }
+        }
+
+        if (ctx->in->buf->last_buf) {
+            ctx->output_closed = 1;
+        }
+
+        *ll = ctx->in;
+        ll = &ctx->in->next;
+
+        ctx->in = ctx->in->next;
+    }
+
+    if (ctx->out) {
+        /* queued control frames */
+
+        *ll = ctx->out;
+
+        for (cl = ctx->out, ll = &cl->next; cl; cl = cl->next) {
+            ll = &cl->next;
+        }
+
+        ctx->out = NULL;
+    }
+
+    f = NULL;
+    last = 0;
+
+    limit = ngx_max(0, ctx->send_window);
+
+    if (limit > ctx->connection->send_window) {
+        limit = ctx->connection->send_window;
+    }
+
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc output limit: %uz w:%z:%uz",
+                   limit, ctx->send_window, ctx->connection->send_window);
+
+#if (NGX_SUPPRESS_WARN)
+    file_pos = 0;
+    pos = NULL;
+    cl = NULL;
+#endif
+
+    in = ctx->in;
+
+    while (in && limit > 0) {
+
+        ngx_log_debug7(NGX_LOG_DEBUG_EVENT, r->connection->log, 0,
+                       "grpc output in  l:%d f:%d %p, pos %p, size: %z "
+                       "file: %O, size: %O",
+                       in->buf->last_buf,
+                       in->buf->in_file,
+                       in->buf->start, in->buf->pos,
+                       in->buf->last - in->buf->pos,
+                       in->buf->file_pos,
+                       in->buf->file_last - in->buf->file_pos);
+
+        if (ngx_buf_special(in->buf)) {
+            goto next;
+        }
+
+        if (in->buf->in_file) {
+            file_pos = in->buf->file_pos;
+
+        } else {
+            pos = in->buf->pos;
+        }
+
+        next = 0;
+
+        do {
+
+            cl = ngx_http_grpc_get_buf(r, ctx);
+            if (cl == NULL) {
+                return NGX_ERROR;
+            }
+
+            b = cl->buf;
+
+            f = (ngx_http_grpc_frame_t *) b->last;
+            b->last += sizeof(ngx_http_grpc_frame_t);
+
+            *ll = cl;
+            ll = &cl->next;
+
+            cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
+            if (cl == NULL) {
+                return NGX_ERROR;
+            }
+
+            b = cl->buf;
+            start = b->start;
+
+            ngx_memcpy(b, in->buf, sizeof(ngx_buf_t));
+
+            /*
+             * restore b->start to preserve memory allocated in the buffer,
+             * to reuse it later for headers and control frames
+             */
+
+            b->start = start;
+
+            if (in->buf->in_file) {
+                b->file_pos = file_pos;
+                file_pos += ngx_min(NGX_HTTP_V2_DEFAULT_FRAME_SIZE, limit);
+
+                if (file_pos >= in->buf->file_last) {
+                    file_pos = in->buf->file_last;
+                    next = 1;
+                }
+
+                b->file_last = file_pos;
+                len = (ngx_uint_t) (file_pos - b->file_pos);
+
+            } else {
+                b->pos = pos;
+                pos += ngx_min(NGX_HTTP_V2_DEFAULT_FRAME_SIZE, limit);
+
+                if (pos >= in->buf->last) {
+                    pos = in->buf->last;
+                    next = 1;
+                }
+
+                b->last = pos;
+                len = (ngx_uint_t) (pos - b->pos);
+            }
+
+            b->tag = (ngx_buf_tag_t) &ngx_http_grpc_body_output_filter;
+            b->shadow = in->buf;
+            b->last_shadow = next;
+
+            b->last_buf = 0;
+            b->last_in_chain = 0;
+
+            *ll = cl;
+            ll = &cl->next;
+
+            f->length_0 = (u_char) ((len >> 16) & 0xff);
+            f->length_1 = (u_char) ((len >> 8) & 0xff);
+            f->length_2 = (u_char) (len & 0xff);
+            f->type = NGX_HTTP_V2_DATA_FRAME;
+            f->flags = 0;
+            f->stream_id_0 = (u_char) ((ctx->id >> 24) & 0xff);
+            f->stream_id_1 = (u_char) ((ctx->id >> 16) & 0xff);
+            f->stream_id_2 = (u_char) ((ctx->id >> 8) & 0xff);
+            f->stream_id_3 = (u_char) (ctx->id & 0xff);
+
+            limit -= len;
+            ctx->send_window -= len;
+            ctx->connection->send_window -= len;
+
+        } while (!next && limit > 0);
+
+        if (!next) {
+            /*
+             * if the buffer wasn't fully sent due to flow control limits,
+             * preserve position for future use
+             */
+
+            if (in->buf->in_file) {
+                in->buf->file_pos = file_pos;
+
+            } else {
+                in->buf->pos = pos;
+            }
+
+            break;
+        }
+
+    next:
+
+        if (in->buf->last_buf) {
+            last = 1;
+        }
+
+        in = in->next;
+    }
+
+    ctx->in = in;
+
+    if (last) {
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc output last");
+
+        ctx->output_closed = 1;
+
+        if (f) {
+            f->flags |= NGX_HTTP_V2_END_STREAM_FLAG;
+
+        } else {
+            cl = ngx_http_grpc_get_buf(r, ctx);
+            if (cl == NULL) {
+                return NGX_ERROR;
+            }
+
+            b = cl->buf;
+
+            f = (ngx_http_grpc_frame_t *) b->last;
+            b->last += sizeof(ngx_http_grpc_frame_t);
+
+            f->length_0 = 0;
+            f->length_1 = 0;
+            f->length_2 = 0;
+            f->type = NGX_HTTP_V2_DATA_FRAME;
+            f->flags = NGX_HTTP_V2_END_STREAM_FLAG;
+            f->stream_id_0 = (u_char) ((ctx->id >> 24) & 0xff);
+            f->stream_id_1 = (u_char) ((ctx->id >> 16) & 0xff);
+            f->stream_id_2 = (u_char) ((ctx->id >> 8) & 0xff);
+            f->stream_id_3 = (u_char) (ctx->id & 0xff);
+
+            *ll = cl;
+            ll = &cl->next;
+        }
+
+        cl->buf->last_buf = 1;
+    }
+
+    *ll = NULL;
+
+#if (NGX_DEBUG)
+
+    for (cl = out; cl; cl = cl->next) {
+        ngx_log_debug7(NGX_LOG_DEBUG_EVENT, r->connection->log, 0,
+                       "grpc output out l:%d f:%d %p, pos %p, size: %z "
+                       "file: %O, size: %O",
+                       cl->buf->last_buf,
+                       cl->buf->in_file,
+                       cl->buf->start, cl->buf->pos,
+                       cl->buf->last - cl->buf->pos,
+                       cl->buf->file_pos,
+                       cl->buf->file_last - cl->buf->file_pos);
+    }
+
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc output limit: %uz w:%z:%uz",
+                   limit, ctx->send_window, ctx->connection->send_window);
+
+#endif
+
+    rc = ngx_chain_writer(&r->upstream->writer, out);
+
+    ngx_chain_update_chains(r->pool, &ctx->free, &ctx->busy, &out,
+                            (ngx_buf_tag_t) &ngx_http_grpc_body_output_filter);
+
+    for (cl = ctx->free; cl; cl = cl->next) {
+
+        /* mark original buffers as sent */
+
+        if (cl->buf->shadow) {
+            if (cl->buf->last_shadow) {
+                b = cl->buf->shadow;
+                b->pos = b->last;
+            }
+
+            cl->buf->shadow = NULL;
+        }
+    }
+
+    if (rc == NGX_OK && ctx->in) {
+        rc = NGX_AGAIN;
+    }
+
+    return rc;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_process_header(ngx_http_request_t *r)
+{
+    ngx_str_t                      *status_line;
+    ngx_int_t                       rc, status;
+    ngx_buf_t                      *b;
+    ngx_table_elt_t                *h;
+    ngx_http_upstream_t            *u;
+    ngx_http_grpc_ctx_t            *ctx;
+    ngx_http_upstream_header_t     *hh;
+    ngx_http_upstream_main_conf_t  *umcf;
+
+    u = r->upstream;
+    b = &u->buffer;
+
+#if (NGX_DEBUG)
+    if (r->connection->log->log_level & NGX_LOG_DEBUG_HTTP) {
+        u_char  buf[512];
+        size_t  n, m;
+
+        n = ngx_min(b->last - b->pos, 256);
+        m = ngx_hex_dump(buf, b->pos, n) - buf;
+
+        ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc response: %*s%s, len: %uz",
+                       m, buf, b->last - b->pos > 256 ? "..." : "",
+                       b->last - b->pos);
+    }
+#endif
+
+    ctx = ngx_http_grpc_get_ctx(r);
+
+    if (ctx == NULL) {
+        return NGX_ERROR;
+    }
+
+    umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);
+
+    for ( ;; ) {
+
+        if (ctx->state < ngx_http_grpc_st_payload) {
+
+            rc = ngx_http_grpc_parse_frame(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+
+                /*
+                 * there can be a lot of window update frames,
+                 * so we reset buffer if it is empty and we haven't
+                 * started parsing headers yet
+                 */
+
+                if (!ctx->parsing_headers) {
+                    b->pos = b->start;
+                    b->last = b->pos;
+                }
+
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            /*
+             * RFC 7540 says that implementations MUST discard frames
+             * that have unknown or unsupported types.  However, extension
+             * frames that appear in the middle of a header block are
+             * not permitted.  Also, for obvious reasons CONTINUATION frames
+             * cannot appear before headers, and DATA frames are not expected
+             * to appear before all headers are parsed.
+             */
+
+            if (ctx->type == NGX_HTTP_V2_DATA_FRAME
+                || (ctx->type == NGX_HTTP_V2_CONTINUATION_FRAME
+                    && !ctx->parsing_headers)
+                || (ctx->type != NGX_HTTP_V2_CONTINUATION_FRAME
+                    && ctx->parsing_headers))
+            {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent unexpected http2 frame: %d",
+                              ctx->type);
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            if (ctx->stream_id && ctx->stream_id != ctx->id) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent frame for unknown stream %ui",
+                              ctx->stream_id);
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+        }
+
+        /* frame payload */
+
+        if (ctx->type == NGX_HTTP_V2_RST_STREAM_FRAME) {
+
+            rc = ngx_http_grpc_parse_rst_stream(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream rejected request with error %ui",
+                          ctx->error);
+
+            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_GOAWAY_FRAME) {
+
+            rc = ngx_http_grpc_parse_goaway(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            /*
+             * If stream_id is lower than one we use, our
+             * request won't be processed and needs to be retried.
+             * If stream_id is greater or equal to the one we use,
+             * we can continue normally (except we can't use this
+             * connection for additional requests).  If there is
+             * a real error, the connection will be closed.
+             */
+
+            if (ctx->stream_id < ctx->id) {
+
+                /* TODO: we can retry non-idempotent requests */
+
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent goaway with error %ui",
+                              ctx->error);
+
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_WINDOW_UPDATE_FRAME) {
+
+            rc = ngx_http_grpc_parse_window_update(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            if (ctx->in) {
+                ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_SETTINGS_FRAME) {
+
+            rc = ngx_http_grpc_parse_settings(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            if (ctx->in) {
+                ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_PING_FRAME) {
+
+            rc = ngx_http_grpc_parse_ping(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+            }
+
+            ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_PUSH_PROMISE_FRAME) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent unexpected push promise frame");
+            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+        }
+
+        if (ctx->type != NGX_HTTP_V2_HEADERS_FRAME
+            && ctx->type != NGX_HTTP_V2_CONTINUATION_FRAME)
+        {
+            /* priority, unknown frames */
+
+            if (b->last - b->pos < (ssize_t) ctx->rest) {
+                ctx->rest -= b->last - b->pos;
+                b->pos = b->last;
+                return NGX_AGAIN;
+            }
+
+            b->pos += ctx->rest;
+            ctx->rest = 0;
+            ctx->state = ngx_http_grpc_st_start;
+
+            continue;
+        }
+
+        /* headers */
+
+        for ( ;; ) {
+
+            rc = ngx_http_grpc_parse_header(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                break;
+            }
+
+            if (rc == NGX_OK) {
+
+                /* a header line has been parsed successfully */
+
+                ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc header: \"%V: %V\"",
+                               &ctx->name, &ctx->value);
+
+                if (ctx->name.len && ctx->name.data[0] == ':') {
+
+                    if (ctx->name.len != sizeof(":status") - 1
+                        || ngx_strncmp(ctx->name.data, ":status",
+                                       sizeof(":status") - 1)
+                           != 0)
+                    {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent invalid header \"%V: %V\"",
+                                      &ctx->name, &ctx->value);
+                        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                    }
+
+                    if (ctx->status) {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent duplicate :status header");
+                        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                    }
+
+                    status_line = &ctx->value;
+
+                    if (status_line->len != 3) {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent invalid :status \"%V\"",
+                                      status_line);
+                        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                    }
+
+                    status = ngx_atoi(status_line->data, 3);
+
+                    if (status == NGX_ERROR) {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent invalid :status \"%V\"",
+                                      status_line);
+                        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                    }
+
+                    if (status < NGX_HTTP_OK) {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent unexpected :status \"%V\"",
+                                      status_line);
+                        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                    }
+
+                    u->headers_in.status_n = status;
+
+                    if (u->state && u->state->status == 0) {
+                        u->state->status = status;
+                    }
+
+                    ctx->status = 1;
+
+                    continue;
+
+                } else if (!ctx->status) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent no :status header");
+                    return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+                }
+
+                h = ngx_list_push(&u->headers_in.headers);
+                if (h == NULL) {
+                    return NGX_ERROR;
+                }
+
+                h->key = ctx->name;
+                h->value = ctx->value;
+                h->lowcase_key = h->key.data;
+                h->hash = ngx_hash_key(h->key.data, h->key.len);
+
+                hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
+                                   h->lowcase_key, h->key.len);
+
+                if (hh && hh->handler(r, h, hh->offset) != NGX_OK) {
+                    return NGX_ERROR;
+                }
+
+                continue;
+            }
+
+            if (rc == NGX_HTTP_PARSE_HEADER_DONE) {
+
+                /* a whole header has been parsed successfully */
+
+                ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc header done");
+
+                if (ctx->end_stream) {
+                    u->headers_in.content_length_n = 0;
+
+                    if (ctx->in == NULL
+                        && ctx->out == NULL
+                        && ctx->output_closed
+                        && b->last == b->pos)
+                    {
+                        u->keepalive = 1;
+                    }
+                }
+
+                return NGX_OK;
+            }
+
+            /* there was error while a header line parsing */
+
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent invalid header");
+
+            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+        }
+
+        /* rc == NGX_AGAIN */
+
+        if (ctx->rest == 0) {
+            ctx->state = ngx_http_grpc_st_start;
+            continue;
+        }
+
+        return NGX_AGAIN;
+    }
+}
+
+
+static ngx_int_t
+ngx_http_grpc_filter_init(void *data)
+{
+    ngx_http_grpc_ctx_t  *ctx = data;
+
+    ngx_http_request_t   *r;
+    ngx_http_upstream_t  *u;
+
+    r = ctx->request;
+    u = r->upstream;
+
+    u->length = 1;
+
+    if (ctx->end_stream) {
+        u->length = 0;
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_filter(void *data, ssize_t bytes)
+{
+    ngx_http_grpc_ctx_t  *ctx = data;
+
+    ngx_int_t             rc;
+    ngx_buf_t            *b, *buf;
+    ngx_chain_t          *cl, **ll;
+    ngx_table_elt_t      *h;
+    ngx_http_request_t   *r;
+    ngx_http_upstream_t  *u;
+
+    r = ctx->request;
+    u = r->upstream;
+    b = &u->buffer;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc filter bytes:%z", bytes);
+
+    b->pos = b->last;
+    b->last += bytes;
+
+    for (cl = u->out_bufs, ll = &u->out_bufs; cl; cl = cl->next) {
+        ll = &cl->next;
+    }
+
+    for ( ;; ) {
+
+        if (ctx->state < ngx_http_grpc_st_payload) {
+
+            rc = ngx_http_grpc_parse_frame(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            if ((ctx->type == NGX_HTTP_V2_CONTINUATION_FRAME
+                 && !ctx->parsing_headers)
+                || (ctx->type != NGX_HTTP_V2_CONTINUATION_FRAME
+                    && ctx->parsing_headers))
+            {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent unexpected http2 frame: %d",
+                              ctx->type);
+                return NGX_ERROR;
+            }
+
+            if (ctx->type == NGX_HTTP_V2_DATA_FRAME) {
+
+                if (ctx->stream_id != ctx->id) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent data frame "
+                                  "for unknown stream %ui",
+                                  ctx->stream_id);
+                    return NGX_ERROR;
+                }
+
+                if (ctx->rest > ctx->recv_window) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream violated stream flow control, "
+                                  "received %uz data frame with window %uz",
+                                  ctx->rest, ctx->recv_window);
+                    return NGX_ERROR;
+                }
+
+                if (ctx->rest > ctx->connection->recv_window) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream violated connection flow control, "
+                                  "received %uz data frame with window %uz",
+                                  ctx->rest, ctx->connection->recv_window);
+                    return NGX_ERROR;
+                }
+
+                ctx->recv_window -= ctx->rest;
+                ctx->connection->recv_window -= ctx->rest;
+
+                if (ctx->connection->recv_window < NGX_HTTP_V2_MAX_WINDOW / 4
+                    || ctx->recv_window < NGX_HTTP_V2_MAX_WINDOW / 4)
+                {
+                    if (ngx_http_grpc_send_window_update(r, ctx) != NGX_OK) {
+                        return NGX_ERROR;
+                    }
+
+                    ngx_post_event(u->peer.connection->write,
+                                   &ngx_posted_events);
+                }
+            }
+
+            if (ctx->stream_id && ctx->stream_id != ctx->id) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent frame for unknown stream %ui",
+                              ctx->stream_id);
+                return NGX_ERROR;
+            }
+
+            ctx->padding = 0;
+        }
+
+        if (ctx->state == ngx_http_grpc_st_padding) {
+
+            if (b->last - b->pos < (ssize_t) ctx->rest) {
+                ctx->rest -= b->last - b->pos;
+                b->pos = b->last;
+                return NGX_AGAIN;
+            }
+
+            b->pos += ctx->rest;
+            ctx->rest = 0;
+            ctx->state = ngx_http_grpc_st_start;
+
+            if (ctx->flags & NGX_HTTP_V2_END_STREAM_FLAG) {
+                u->length = 0;
+
+                if (ctx->in == NULL
+                    && ctx->out == NULL
+                    && ctx->output_closed
+                    && b->last == b->pos)
+                {
+                    u->keepalive = 1;
+                }
+
+                break;
+            }
+
+            continue;
+        }
+
+        /* frame payload */
+
+        if (ctx->type == NGX_HTTP_V2_RST_STREAM_FRAME) {
+
+            rc = ngx_http_grpc_parse_rst_stream(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream rejected request with error %ui",
+                          ctx->error);
+
+            return NGX_ERROR;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_GOAWAY_FRAME) {
+
+            rc = ngx_http_grpc_parse_goaway(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            /*
+             * If stream_id is lower than one we use, our
+             * request won't be processed and needs to be retried.
+             * If stream_id is greater or equal to the one we use,
+             * we can continue normally (except we can't use this
+             * connection for additional requests).  If there is
+             * a real error, the connection will be closed.
+             */
+
+            if (ctx->stream_id < ctx->id) {
+
+                /* TODO: we can retry non-idempotent requests */
+
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent goaway with error %ui",
+                              ctx->error);
+
+                return NGX_ERROR;
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_WINDOW_UPDATE_FRAME) {
+
+            rc = ngx_http_grpc_parse_window_update(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            if (ctx->in) {
+                ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_SETTINGS_FRAME) {
+
+            rc = ngx_http_grpc_parse_settings(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            if (ctx->in) {
+                ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            }
+
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_PING_FRAME) {
+
+            rc = ngx_http_grpc_parse_ping(r, ctx, b);
+
+            if (rc == NGX_AGAIN) {
+                return NGX_AGAIN;
+            }
+
+            if (rc == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+
+            ngx_post_event(u->peer.connection->write, &ngx_posted_events);
+            continue;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_PUSH_PROMISE_FRAME) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent unexpected push promise frame");
+            return NGX_ERROR;
+        }
+
+        if (ctx->type == NGX_HTTP_V2_HEADERS_FRAME
+            || ctx->type == NGX_HTTP_V2_CONTINUATION_FRAME)
+        {
+            for ( ;; ) {
+
+                rc = ngx_http_grpc_parse_header(r, ctx, b);
+
+                if (rc == NGX_AGAIN) {
+                    break;
+                }
+
+                if (rc == NGX_OK) {
+
+                    /* a header line has been parsed successfully */
+
+                    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                                   "grpc trailer: \"%V: %V\"",
+                                   &ctx->name, &ctx->value);
+
+                    if (ctx->name.len && ctx->name.data[0] == ':') {
+                        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                      "upstream sent invalid "
+                                      "trailer \"%V: %V\"",
+                                      &ctx->name, &ctx->value);
+                        return NGX_ERROR;
+                    }
+
+                    h = ngx_list_push(&u->headers_in.trailers);
+                    if (h == NULL) {
+                        return NGX_ERROR;
+                    }
+
+                    h->key = ctx->name;
+                    h->value = ctx->value;
+                    h->lowcase_key = h->key.data;
+                    h->hash = ngx_hash_key(h->key.data, h->key.len);
+
+                    continue;
+                }
+
+                if (rc == NGX_HTTP_PARSE_HEADER_DONE) {
+
+                    /* a whole header has been parsed successfully */
+
+                    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                                   "grpc trailer done");
+
+                    if (ctx->end_stream) {
+                        u->length = 0;
+
+                        if (ctx->in == NULL
+                            && ctx->out == NULL
+                            && ctx->output_closed
+                            && b->last == b->pos)
+                        {
+                            u->keepalive = 1;
+                        }
+
+                        return NGX_OK;
+                    }
+
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent trailer without "
+                                  "end stream flag");
+                    return NGX_ERROR;
+                }
+
+                /* there was error while a header line parsing */
+
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent invalid trailer");
+
+                return NGX_ERROR;
+            }
+
+            /* rc == NGX_AGAIN */
+
+            if (ctx->rest == 0) {
+                ctx->state = ngx_http_grpc_st_start;
+                continue;
+            }
+
+            return NGX_AGAIN;
+        }
+
+        if (ctx->type != NGX_HTTP_V2_DATA_FRAME) {
+
+            /* priority, unknown frames */
+
+            if (b->last - b->pos < (ssize_t) ctx->rest) {
+                ctx->rest -= b->last - b->pos;
+                b->pos = b->last;
+                return NGX_AGAIN;
+            }
+
+            b->pos += ctx->rest;
+            ctx->rest = 0;
+            ctx->state = ngx_http_grpc_st_start;
+
+            continue;
+        }
+
+        /*
+         * data frame:
+         *
+         * +---------------+
+         * |Pad Length? (8)|
+         * +---------------+-----------------------------------------------+
+         * |                            Data (*)                         ...
+         * +---------------------------------------------------------------+
+         * |                           Padding (*)                       ...
+         * +---------------------------------------------------------------+
+         */
+
+        if (ctx->flags & NGX_HTTP_V2_PADDED_FLAG) {
+
+            if (ctx->rest == 0) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent too short http2 frame");
+                return NGX_ERROR;
+            }
+
+            if (b->pos == b->last) {
+                return NGX_AGAIN;
+            }
+
+            ctx->flags &= ~NGX_HTTP_V2_PADDED_FLAG;
+            ctx->padding = *b->pos++;
+            ctx->rest -= 1;
+
+            if (ctx->padding > ctx->rest) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent http2 frame with too long "
+                              "padding: %d in frame %uz",
+                              ctx->padding, ctx->rest);
+                return NGX_ERROR;
+            }
+
+            continue;
+        }
+
+        if (ctx->rest == ctx->padding) {
+            goto done;
+        }
+
+        if (b->pos == b->last) {
+            return NGX_AGAIN;
+        }
+
+        cl = ngx_chain_get_free_buf(r->pool, &u->free_bufs);
+        if (cl == NULL) {
+            return NGX_ERROR;
+        }
+
+        *ll = cl;
+        ll = &cl->next;
+
+        buf = cl->buf;
+
+        buf->flush = 1;
+        buf->memory = 1;
+
+        buf->pos = b->pos;
+        buf->tag = u->output.tag;
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc output buf %p", buf->pos);
+
+        if (b->last - b->pos < (ssize_t) ctx->rest - ctx->padding) {
+
+            ctx->rest -= b->last - b->pos;
+            b->pos = b->last;
+            buf->last = b->pos;
+
+            return NGX_AGAIN;
+        }
+
+        b->pos += ctx->rest - ctx->padding;
+        buf->last = b->pos;
+        ctx->rest = ctx->padding;
+
+    done:
+
+        if (ctx->padding) {
+            ctx->state = ngx_http_grpc_st_padding;
+            continue;
+        }
+
+        ctx->state = ngx_http_grpc_st_start;
+
+        if (ctx->flags & NGX_HTTP_V2_END_STREAM_FLAG) {
+            u->length = 0;
+
+            if (ctx->in == NULL
+                && ctx->out == NULL
+                && ctx->output_closed
+                && b->last == b->pos)
+            {
+                u->keepalive = 1;
+            }
+
+            break;
+        }
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_frame(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char                 ch, *p;
+    ngx_http_grpc_state_e  state;
+
+    state = ctx->state;
+
+    for (p = b->pos; p < b->last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc frame byte: %02Xd, s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case ngx_http_grpc_st_start:
+            ctx->rest = ch << 16;
+            state = ngx_http_grpc_st_length_2;
+            break;
+
+        case ngx_http_grpc_st_length_2:
+            ctx->rest |= ch << 8;
+            state = ngx_http_grpc_st_length_3;
+            break;
+
+        case ngx_http_grpc_st_length_3:
+            ctx->rest |= ch;
+
+            if (ctx->rest > NGX_HTTP_V2_DEFAULT_FRAME_SIZE) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent too large http2 frame: %uz",
+                              ctx->rest);
+                return NGX_ERROR;
+            }
+
+            state = ngx_http_grpc_st_type;
+            break;
+
+        case ngx_http_grpc_st_type:
+            ctx->type = ch;
+            state = ngx_http_grpc_st_flags;
+            break;
+
+        case ngx_http_grpc_st_flags:
+            ctx->flags = ch;
+            state = ngx_http_grpc_st_stream_id;
+            break;
+
+        case ngx_http_grpc_st_stream_id:
+            ctx->stream_id = (ch & 0x7f) << 24;
+            state = ngx_http_grpc_st_stream_id_2;
+            break;
+
+        case ngx_http_grpc_st_stream_id_2:
+            ctx->stream_id |= ch << 16;
+            state = ngx_http_grpc_st_stream_id_3;
+            break;
+
+        case ngx_http_grpc_st_stream_id_3:
+            ctx->stream_id |= ch << 8;
+            state = ngx_http_grpc_st_stream_id_4;
+            break;
+
+        case ngx_http_grpc_st_stream_id_4:
+            ctx->stream_id |= ch;
+
+            ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc frame: %d, len: %uz, f:%d, i:%ui",
+                           ctx->type, ctx->rest, ctx->flags, ctx->stream_id);
+
+            b->pos = p + 1;
+
+            ctx->state = ngx_http_grpc_st_payload;
+            ctx->frame_state = 0;
+
+            return NGX_OK;
+
+        /* suppress warning */
+        case ngx_http_grpc_st_payload:
+        case ngx_http_grpc_st_padding:
+            break;
+        }
+    }
+
+    b->pos = p;
+    ctx->state = state;
+
+    return NGX_AGAIN;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_header(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char     ch, *p, *last;
+    size_t     min;
+    ngx_int_t  rc;
+    enum {
+        sw_start = 0,
+        sw_padding_length,
+        sw_dependency,
+        sw_dependency_2,
+        sw_dependency_3,
+        sw_dependency_4,
+        sw_weight,
+        sw_fragment,
+        sw_padding
+    } state;
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc parse header: start");
+
+        if (ctx->type == NGX_HTTP_V2_HEADERS_FRAME) {
+            ctx->parsing_headers = 1;
+            ctx->fragment_state = 0;
+
+            min = (ctx->flags & NGX_HTTP_V2_PADDED_FLAG ? 1 : 0)
+                  + (ctx->flags & NGX_HTTP_V2_PRIORITY_FLAG ? 5 : 0);
+
+            if (ctx->rest < min) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent headers frame "
+                              "with invalid length: %uz",
+                              ctx->rest);
+                return NGX_ERROR;
+            }
+
+            if (ctx->flags & NGX_HTTP_V2_END_STREAM_FLAG) {
+                ctx->end_stream = 1;
+            }
+
+            if (ctx->flags & NGX_HTTP_V2_PADDED_FLAG) {
+                state = sw_padding_length;
+
+            } else if (ctx->flags & NGX_HTTP_V2_PRIORITY_FLAG) {
+                state = sw_dependency;
+
+            } else {
+                state = sw_fragment;
+            }
+
+        } else if (ctx->type == NGX_HTTP_V2_CONTINUATION_FRAME) {
+            state = sw_fragment;
+        }
+
+        ctx->padding = 0;
+        ctx->frame_state = state;
+    }
+
+    if (state < sw_fragment) {
+
+        if (b->last - b->pos < (ssize_t) ctx->rest) {
+            last = b->last;
+
+        } else {
+            last = b->pos + ctx->rest;
+        }
+
+        for (p = b->pos; p < last; p++) {
+            ch = *p;
+
+#if 0
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc header byte: %02Xd s:%d", ch, state);
+#endif
+
+            /*
+             * headers frame:
+             *
+             * +---------------+
+             * |Pad Length? (8)|
+             * +-+-------------+----------------------------------------------+
+             * |E|                 Stream Dependency? (31)                    |
+             * +-+-------------+----------------------------------------------+
+             * |  Weight? (8)  |
+             * +-+-------------+----------------------------------------------+
+             * |                   Header Block Fragment (*)                ...
+             * +--------------------------------------------------------------+
+             * |                           Padding (*)                      ...
+             * +--------------------------------------------------------------+
+             */
+
+            switch (state) {
+
+            case sw_padding_length:
+
+                ctx->padding = ch;
+
+                if (ctx->flags & NGX_HTTP_V2_PRIORITY_FLAG) {
+                    state = sw_dependency;
+                    break;
+                }
+
+                goto fragment;
+
+            case sw_dependency:
+                state = sw_dependency_2;
+                break;
+
+            case sw_dependency_2:
+                state = sw_dependency_3;
+                break;
+
+            case sw_dependency_3:
+                state = sw_dependency_4;
+                break;
+
+            case sw_dependency_4:
+                state = sw_weight;
+                break;
+
+            case sw_weight:
+                goto fragment;
+
+            /* suppress warning */
+            case sw_start:
+            case sw_fragment:
+            case sw_padding:
+                break;
+            }
+        }
+
+        ctx->rest -= p - b->pos;
+        b->pos = p;
+
+        ctx->frame_state = state;
+        return NGX_AGAIN;
+
+    fragment:
+
+        p++;
+        ctx->rest -= p - b->pos;
+        b->pos = p;
+
+        if (ctx->padding > ctx->rest) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent http2 frame with too long "
+                          "padding: %d in frame %uz",
+                          ctx->padding, ctx->rest);
+            return NGX_ERROR;
+        }
+
+        state = sw_fragment;
+        ctx->frame_state = state;
+    }
+
+    if (state == sw_fragment) {
+
+        rc = ngx_http_grpc_parse_fragment(r, ctx, b);
+
+        if (rc == NGX_AGAIN) {
+            return NGX_AGAIN;
+        }
+
+        if (rc == NGX_ERROR) {
+            return NGX_ERROR;
+        }
+
+        if (rc == NGX_OK) {
+            return NGX_OK;
+        }
+
+        /* rc == NGX_DONE */
+
+        state = sw_padding;
+        ctx->frame_state = state;
+    }
+
+    if (state == sw_padding) {
+
+        if (b->last - b->pos < (ssize_t) ctx->rest) {
+
+            ctx->rest -= b->last - b->pos;
+            b->pos = b->last;
+
+            return NGX_AGAIN;
+        }
+
+        b->pos += ctx->rest;
+        ctx->rest = 0;
+
+        ctx->state = ngx_http_grpc_st_start;
+
+        if (ctx->flags & NGX_HTTP_V2_END_HEADERS_FLAG) {
+
+            if (ctx->fragment_state) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent truncated http2 header");
+                return NGX_ERROR;
+            }
+
+            ctx->parsing_headers = 0;
+
+            return NGX_HTTP_PARSE_HEADER_DONE;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    /* unreachable */
+
+    return NGX_ERROR;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_fragment(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char      ch, *p, *last;
+    size_t      size;
+    ngx_uint_t  index, size_update;
+    enum {
+        sw_start = 0,
+        sw_index,
+        sw_name_length,
+        sw_name_length_2,
+        sw_name_length_3,
+        sw_name_length_4,
+        sw_name,
+        sw_name_bytes,
+        sw_value_length,
+        sw_value_length_2,
+        sw_value_length_3,
+        sw_value_length_4,
+        sw_value,
+        sw_value_bytes
+    } state;
+
+    /* header block fragment */
+
+#if 0
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc header fragment %p:%p rest:%uz",
+                   b->pos, b->last, ctx->rest);
+#endif
+
+    if (b->last - b->pos < (ssize_t) ctx->rest - ctx->padding) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest - ctx->padding;
+    }
+
+    state = ctx->fragment_state;
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc header byte: %02Xd s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case sw_start:
+            ctx->index = 0;
+
+            if ((ch & 0x80) == 0x80) {
+                /*
+                 * indexed header:
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 1 |        Index (7+)         |
+                 * +---+---------------------------+
+                 */
+
+                index = ch & ~0x80;
+
+                if (index == 0 || index > 61) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent invalid http2 "
+                                  "table index: %ui", index);
+                    return NGX_ERROR;
+                }
+
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc indexed header: %ui", index);
+
+                ctx->index = index;
+                ctx->literal = 0;
+
+                goto done;
+
+            } else if ((ch & 0xc0) == 0x40) {
+                /*
+                 * literal header with incremental indexing:
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 1 |      Index (6+)       |
+                 * +---+---+-----------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 1 |           0           |
+                 * +---+---+-----------------------+
+                 * | H |     Name Length (7+)      |
+                 * +---+---------------------------+
+                 * |  Name String (Length octets)  |
+                 * +---+---------------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 */
+
+                index = ch & ~0xc0;
+
+                if (index > 61) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent invalid http2 "
+                                  "table index: %ui", index);
+                    return NGX_ERROR;
+                }
+
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc literal header: %ui", index);
+
+                if (index == 0) {
+                    state = sw_name_length;
+                    break;
+                }
+
+                ctx->index = index;
+                ctx->literal = 1;
+
+                state = sw_value_length;
+                break;
+
+            } else if ((ch & 0xe0) == 0x20) {
+                /*
+                 * dynamic table size update:
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 0 | 1 |   Max size (5+)   |
+                 * +---+---------------------------+
+                 */
+
+                size_update = ch & ~0xe0;
+
+                if (size_update > 0) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent invalid http2 "
+                                  "dynamic table size update: %ui",
+                                  size_update);
+                    return NGX_ERROR;
+                }
+
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc table size update: %ui", size_update);
+
+                break;
+
+            } else if ((ch & 0xf0) == 0x10) {
+                /*
+                 *  literal header field never indexed:
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 0 | 0 | 1 |  Index (4+)   |
+                 * +---+---+-----------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 0 | 0 | 1 |       0       |
+                 * +---+---+-----------------------+
+                 * | H |     Name Length (7+)      |
+                 * +---+---------------------------+
+                 * |  Name String (Length octets)  |
+                 * +---+---------------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 */
+
+                index = ch & ~0xf0;
+
+                if (index == 0x0f) {
+                    ctx->index = index;
+                    ctx->literal = 1;
+                    state = sw_index;
+                    break;
+                }
+
+                if (index == 0) {
+                    state = sw_name_length;
+                    break;
+                }
+
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc literal header never indexed: %ui",
+                               index);
+
+                ctx->index = index;
+                ctx->literal = 1;
+
+                state = sw_value_length;
+                break;
+
+            } else if ((ch & 0xf0) == 0x00) {
+                /*
+                 * literal header field without indexing:
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 0 | 0 | 0 |  Index (4+)   |
+                 * +---+---+-----------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 *
+                 *   0   1   2   3   4   5   6   7
+                 * +---+---+---+---+---+---+---+---+
+                 * | 0 | 0 | 0 | 0 |       0       |
+                 * +---+---+-----------------------+
+                 * | H |     Name Length (7+)      |
+                 * +---+---------------------------+
+                 * |  Name String (Length octets)  |
+                 * +---+---------------------------+
+                 * | H |     Value Length (7+)     |
+                 * +---+---------------------------+
+                 * | Value String (Length octets)  |
+                 * +-------------------------------+
+                 */
+
+                index = ch & ~0xf0;
+
+                if (index == 0x0f) {
+                    ctx->index = index;
+                    ctx->literal = 1;
+                    state = sw_index;
+                    break;
+                }
+
+                if (index == 0) {
+                    state = sw_name_length;
+                    break;
+                }
+
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "grpc literal header without indexing: %ui",
+                               index);
+
+                ctx->index = index;
+                ctx->literal = 1;
+
+                state = sw_value_length;
+                break;
+            }
+
+            /* not reached */
+
+            return NGX_ERROR;
+
+        case sw_index:
+            ctx->index = ctx->index + (ch & ~0x80);
+
+            if (ch & 0x80) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent http2 table index "
+                              "with continuation flag");
+                return NGX_ERROR;
+            }
+
+            if (ctx->index > 61) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent invalid http2 "
+                              "table index: %ui", ctx->index);
+                return NGX_ERROR;
+            }
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc header index: %ui", ctx->index);
+
+            state = sw_value_length;
+            break;
+
+        case sw_name_length:
+            ctx->field_huffman = ch & 0x80 ? 1 : 0;
+            ctx->field_length = ch & ~0x80;
+
+            if (ctx->field_length == 0x7f) {
+                state = sw_name_length_2;
+                break;
+            }
+
+            if (ctx->field_length == 0) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent zero http2 "
+                              "header name length");
+                return NGX_ERROR;
+            }
+
+            state = sw_name;
+            break;
+
+        case sw_name_length_2:
+            ctx->field_length += ch & ~0x80;
+
+            if (ch & 0x80) {
+                state = sw_name_length_3;
+                break;
+            }
+
+            state = sw_name;
+            break;
+
+        case sw_name_length_3:
+            ctx->field_length += (ch & ~0x80) << 7;
+
+            if (ch & 0x80) {
+                state = sw_name_length_4;
+                break;
+            }
+
+            state = sw_name;
+            break;
+
+        case sw_name_length_4:
+            ctx->field_length += (ch & ~0x80) << 14;
+
+            if (ch & 0x80) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent too large http2 "
+                              "header name length");
+                return NGX_ERROR;
+            }
+
+            state = sw_name;
+            break;
+
+        case sw_name:
+            ctx->name.len = ctx->field_huffman ?
+                            ctx->field_length * 8 / 5 : ctx->field_length;
+
+            ctx->name.data = ngx_pnalloc(r->pool, ctx->name.len + 1);
+            if (ctx->name.data == NULL) {
+                return NGX_ERROR;
+            }
+
+            ctx->field_end = ctx->name.data;
+            ctx->field_rest = ctx->field_length;
+            ctx->field_state = 0;
+
+            state = sw_name_bytes;
+
+            /* fall through */
+
+        case sw_name_bytes:
+
+            ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc name: len:%uz h:%d last:%uz, rest:%uz",
+                           ctx->field_length,
+                           ctx->field_huffman,
+                           last - p,
+                           ctx->rest - (p - b->pos));
+
+            size = ngx_min(last - p, (ssize_t) ctx->field_rest);
+            ctx->field_rest -= size;
+
+            if (ctx->field_huffman) {
+                if (ngx_http_v2_huff_decode(&ctx->field_state, p, size,
+                                            &ctx->field_end,
+                                            ctx->field_rest == 0,
+                                            r->connection->log)
+                    != NGX_OK)
+                {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent invalid encoded header");
+                    return NGX_ERROR;
+                }
+
+                ctx->name.len = ctx->field_end - ctx->name.data;
+                ctx->name.data[ctx->name.len] = '\0';
+
+            } else {
+                ctx->field_end = ngx_cpymem(ctx->field_end, p, size);
+                ctx->name.data[ctx->name.len] = '\0';
+            }
+
+            p += size - 1;
+
+            if (ctx->field_rest == 0) {
+                state = sw_value_length;
+            }
+
+            break;
+
+        case sw_value_length:
+            ctx->field_huffman = ch & 0x80 ? 1 : 0;
+            ctx->field_length = ch & ~0x80;
+
+            if (ctx->field_length == 0x7f) {
+                state = sw_value_length_2;
+                break;
+            }
+
+            if (ctx->field_length == 0) {
+                ngx_str_set(&ctx->value, "");
+                goto done;
+            }
+
+            state = sw_value;
+            break;
+
+        case sw_value_length_2:
+            ctx->field_length += ch & ~0x80;
+
+            if (ch & 0x80) {
+                state = sw_value_length_3;
+                break;
+            }
+
+            state = sw_value;
+            break;
+
+        case sw_value_length_3:
+            ctx->field_length += (ch & ~0x80) << 7;
+
+            if (ch & 0x80) {
+                state = sw_value_length_4;
+                break;
+            }
+
+            state = sw_value;
+            break;
+
+        case sw_value_length_4:
+            ctx->field_length += (ch & ~0x80) << 14;
+
+            if (ch & 0x80) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent too large http2 "
+                              "header value length");
+                return NGX_ERROR;
+            }
+
+            state = sw_value;
+            break;
+
+        case sw_value:
+            ctx->value.len = ctx->field_huffman ?
+                             ctx->field_length * 8 / 5 : ctx->field_length;
+
+            ctx->value.data = ngx_pnalloc(r->pool, ctx->value.len + 1);
+            if (ctx->value.data == NULL) {
+                return NGX_ERROR;
+            }
+
+            ctx->field_end = ctx->value.data;
+            ctx->field_rest = ctx->field_length;
+            ctx->field_state = 0;
+
+            state = sw_value_bytes;
+
+            /* fall through */
+
+        case sw_value_bytes:
+
+            ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc value: len:%uz h:%d last:%uz, rest:%uz",
+                           ctx->field_length,
+                           ctx->field_huffman,
+                           last - p,
+                           ctx->rest - (p - b->pos));
+
+            size = ngx_min(last - p, (ssize_t) ctx->field_rest);
+            ctx->field_rest -= size;
+
+            if (ctx->field_huffman) {
+                if (ngx_http_v2_huff_decode(&ctx->field_state, p, size,
+                                            &ctx->field_end,
+                                            ctx->field_rest == 0,
+                                            r->connection->log)
+                    != NGX_OK)
+                {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent invalid encoded header");
+                    return NGX_ERROR;
+                }
+
+                ctx->value.len = ctx->field_end - ctx->value.data;
+                ctx->value.data[ctx->value.len] = '\0';
+
+            } else {
+                ctx->field_end = ngx_cpymem(ctx->field_end, p, size);
+                ctx->value.data[ctx->value.len] = '\0';
+            }
+
+            p += size - 1;
+
+            if (ctx->field_rest == 0) {
+                goto done;
+            }
+
+            break;
+        }
+
+        continue;
+
+    done:
+
+        p++;
+        ctx->rest -= p - b->pos;
+        ctx->fragment_state = sw_start;
+        b->pos = p;
+
+        if (ctx->index) {
+            ctx->name = *ngx_http_v2_get_static_name(ctx->index);
+        }
+
+        if (ctx->index && !ctx->literal) {
+            ctx->value = *ngx_http_v2_get_static_value(ctx->index);
+        }
+
+        if (!ctx->index) {
+            if (ngx_http_grpc_validate_header_name(r, &ctx->name) != NGX_OK) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent invalid header: \"%V: %V\"",
+                              &ctx->name, &ctx->value);
+                return NGX_ERROR;
+            }
+        }
+
+        if (!ctx->index || ctx->literal) {
+            if (ngx_http_grpc_validate_header_value(r, &ctx->value) != NGX_OK) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent invalid header: \"%V: %V\"",
+                              &ctx->name, &ctx->value);
+                return NGX_ERROR;
+            }
+        }
+
+        return NGX_OK;
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->fragment_state = state;
+    b->pos = p;
+
+    if (ctx->rest > ctx->padding) {
+        return NGX_AGAIN;
+    }
+
+    return NGX_DONE;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_validate_header_name(ngx_http_request_t *r, ngx_str_t *s)
+{
+    u_char      ch;
+    ngx_uint_t  i;
+
+    for (i = 0; i < s->len; i++) {
+        ch = s->data[i];
+
+        if (ch == ':' && i > 0) {
+            return NGX_ERROR;
+        }
+
+        if (ch >= 'A' && ch <= 'Z') {
+            return NGX_ERROR;
+        }
+
+        if (ch == '\0' || ch == CR || ch == LF) {
+            return NGX_ERROR;
+        }
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_validate_header_value(ngx_http_request_t *r, ngx_str_t *s)
+{
+    u_char      ch;
+    ngx_uint_t  i;
+
+    for (i = 0; i < s->len; i++) {
+        ch = s->data[i];
+
+        if (ch == '\0' || ch == CR || ch == LF) {
+            return NGX_ERROR;
+        }
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_rst_stream(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char  ch, *p, *last;
+    enum {
+        sw_start = 0,
+        sw_error_2,
+        sw_error_3,
+        sw_error_4
+    } state;
+
+    if (b->last - b->pos < (ssize_t) ctx->rest) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest;
+    }
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+        if (ctx->rest != 4) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent rst stream frame "
+                          "with invalid length: %uz",
+                          ctx->rest);
+            return NGX_ERROR;
+        }
+    }
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc rst byte: %02Xd s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case sw_start:
+            ctx->error = ch << 24;
+            state = sw_error_2;
+            break;
+
+        case sw_error_2:
+            ctx->error |= ch << 16;
+            state = sw_error_3;
+            break;
+
+        case sw_error_3:
+            ctx->error |= ch << 8;
+            state = sw_error_4;
+            break;
+
+        case sw_error_4:
+            ctx->error |= ch;
+            state = sw_start;
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc error: %ui", ctx->error);
+
+            break;
+        }
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->frame_state = state;
+    b->pos = p;
+
+    if (ctx->rest > 0) {
+        return NGX_AGAIN;
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_goaway(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char  ch, *p, *last;
+    enum {
+        sw_start = 0,
+        sw_last_stream_id_2,
+        sw_last_stream_id_3,
+        sw_last_stream_id_4,
+        sw_error,
+        sw_error_2,
+        sw_error_3,
+        sw_error_4,
+        sw_debug
+    } state;
+
+    if (b->last - b->pos < (ssize_t) ctx->rest) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest;
+    }
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+
+        if (ctx->stream_id) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent goaway frame "
+                          "with non-zero stream id: %ui",
+                          ctx->stream_id);
+            return NGX_ERROR;
+        }
+
+        if (ctx->rest < 8) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent goaway frame "
+                          "with invalid length: %uz",
+                          ctx->rest);
+            return NGX_ERROR;
+        }
+    }
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc goaway byte: %02Xd s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case sw_start:
+            ctx->stream_id = (ch & 0x7f) << 24;
+            state = sw_last_stream_id_2;
+            break;
+
+        case sw_last_stream_id_2:
+            ctx->stream_id |= ch << 16;
+            state = sw_last_stream_id_3;
+            break;
+
+        case sw_last_stream_id_3:
+            ctx->stream_id |= ch << 8;
+            state = sw_last_stream_id_4;
+            break;
+
+        case sw_last_stream_id_4:
+            ctx->stream_id |= ch;
+            state = sw_error;
+            break;
+
+        case sw_error:
+            ctx->error = ch << 24;
+            state = sw_error_2;
+            break;
+
+        case sw_error_2:
+            ctx->error |= ch << 16;
+            state = sw_error_3;
+            break;
+
+        case sw_error_3:
+            ctx->error |= ch << 8;
+            state = sw_error_4;
+            break;
+
+        case sw_error_4:
+            ctx->error |= ch;
+            state = sw_debug;
+            break;
+
+        case sw_debug:
+            break;
+        }
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->frame_state = state;
+    b->pos = p;
+
+    if (ctx->rest > 0) {
+        return NGX_AGAIN;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc goaway: %ui, stream %ui",
+                   ctx->error, ctx->stream_id);
+
+    ctx->state = ngx_http_grpc_st_start;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_window_update(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b)
+{
+    u_char  ch, *p, *last;
+    enum {
+        sw_start = 0,
+        sw_size_2,
+        sw_size_3,
+        sw_size_4
+    } state;
+
+    if (b->last - b->pos < (ssize_t) ctx->rest) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest;
+    }
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+        if (ctx->rest != 4) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent window update frame "
+                          "with invalid length: %uz",
+                          ctx->rest);
+            return NGX_ERROR;
+        }
+    }
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc window update byte: %02Xd s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case sw_start:
+            ctx->window_update = (ch & 0x7f) << 24;
+            state = sw_size_2;
+            break;
+
+        case sw_size_2:
+            ctx->window_update |= ch << 16;
+            state = sw_size_3;
+            break;
+
+        case sw_size_3:
+            ctx->window_update |= ch << 8;
+            state = sw_size_4;
+            break;
+
+        case sw_size_4:
+            ctx->window_update |= ch;
+            state = sw_start;
+            break;
+        }
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->frame_state = state;
+    b->pos = p;
+
+    if (ctx->rest > 0) {
+        return NGX_AGAIN;
+    }
+
+    ctx->state = ngx_http_grpc_st_start;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc window update: %ui", ctx->window_update);
+
+    if (ctx->stream_id) {
+
+        if (ctx->window_update > (size_t) NGX_HTTP_V2_MAX_WINDOW
+                                 - ctx->send_window)
+        {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent too large window update");
+            return NGX_ERROR;
+        }
+
+        ctx->send_window += ctx->window_update;
+
+    } else {
+
+        if (ctx->window_update > NGX_HTTP_V2_MAX_WINDOW
+                                 - ctx->connection->send_window)
+        {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent too large window update");
+            return NGX_ERROR;
+        }
+
+        ctx->connection->send_window += ctx->window_update;
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_settings(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx,
+    ngx_buf_t *b)
+{
+    u_char   ch, *p, *last;
+    ssize_t  window_update;
+    enum {
+        sw_start = 0,
+        sw_id,
+        sw_id_2,
+        sw_value,
+        sw_value_2,
+        sw_value_3,
+        sw_value_4
+    } state;
+
+    if (b->last - b->pos < (ssize_t) ctx->rest) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest;
+    }
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+
+        if (ctx->stream_id) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent settings frame "
+                          "with non-zero stream id: %ui",
+                          ctx->stream_id);
+            return NGX_ERROR;
+        }
+
+        if (ctx->flags & NGX_HTTP_V2_ACK_FLAG) {
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc settings ack");
+
+            if (ctx->rest != 0) {
+                ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                              "upstream sent settings frame "
+                              "with ack flag and non-zero length: %uz",
+                              ctx->rest);
+                return NGX_ERROR;
+            }
+
+            ctx->state = ngx_http_grpc_st_start;
+
+            return NGX_OK;
+        }
+
+        if (ctx->rest % 6 != 0) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent settings frame "
+                          "with invalid length: %uz",
+                          ctx->rest);
+            return NGX_ERROR;
+        }
+    }
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc settings byte: %02Xd s:%d", ch, state);
+#endif
+
+        switch (state) {
+
+        case sw_start:
+        case sw_id:
+            ctx->setting_id = ch << 8;
+            state = sw_id_2;
+            break;
+
+        case sw_id_2:
+            ctx->setting_id |= ch;
+            state = sw_value;
+            break;
+
+        case sw_value:
+            ctx->setting_value = ch << 24;
+            state = sw_value_2;
+            break;
+
+        case sw_value_2:
+            ctx->setting_value |= ch << 16;
+            state = sw_value_3;
+            break;
+
+        case sw_value_3:
+            ctx->setting_value |= ch << 8;
+            state = sw_value_4;
+            break;
+
+        case sw_value_4:
+            ctx->setting_value |= ch;
+            state = sw_id;
+
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc setting: %ui %ui",
+                           ctx->setting_id, ctx->setting_value);
+
+            /*
+             * The following settings are defined by the protocol:
+             *
+             * SETTINGS_HEADER_TABLE_SIZE, SETTINGS_ENABLE_PUSH,
+             * SETTINGS_MAX_CONCURRENT_STREAMS, SETTINGS_INITIAL_WINDOW_SIZE,
+             * SETTINGS_MAX_FRAME_SIZE, SETTINGS_MAX_HEADER_LIST_SIZE
+             *
+             * Only SETTINGS_INITIAL_WINDOW_SIZE seems to be needed in
+             * a simple client.
+             */
+
+            if (ctx->setting_id == 0x04) {
+                /* SETTINGS_INITIAL_WINDOW_SIZE */
+
+                if (ctx->setting_value > NGX_HTTP_V2_MAX_WINDOW) {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent settings frame "
+                                  "with too large initial window size: %ui",
+                                  ctx->setting_value);
+                    return NGX_ERROR;
+                }
+
+                window_update = ctx->setting_value
+                                - ctx->connection->init_window;
+                ctx->connection->init_window = ctx->setting_value;
+
+                if (ctx->send_window > 0
+                    && window_update > (ssize_t) NGX_HTTP_V2_MAX_WINDOW
+                                       - ctx->send_window)
+                {
+                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                                  "upstream sent settings frame "
+                                  "with too large initial window size: %ui",
+                                  ctx->setting_value);
+                    return NGX_ERROR;
+                }
+
+                ctx->send_window += window_update;
+            }
+
+            break;
+        }
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->frame_state = state;
+    b->pos = p;
+
+    if (ctx->rest > 0) {
+        return NGX_AGAIN;
+    }
+
+    ctx->state = ngx_http_grpc_st_start;
+
+    return ngx_http_grpc_send_settings_ack(r, ctx);
+}
+
+
+static ngx_int_t
+ngx_http_grpc_parse_ping(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_buf_t *b)
+{
+    u_char  ch, *p, *last;
+    enum {
+        sw_start = 0,
+        sw_data_2,
+        sw_data_3,
+        sw_data_4,
+        sw_data_5,
+        sw_data_6,
+        sw_data_7,
+        sw_data_8
+    } state;
+
+    if (b->last - b->pos < (ssize_t) ctx->rest) {
+        last = b->last;
+
+    } else {
+        last = b->pos + ctx->rest;
+    }
+
+    state = ctx->frame_state;
+
+    if (state == sw_start) {
+
+        if (ctx->stream_id) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent ping frame "
+                          "with non-zero stream id: %ui",
+                          ctx->stream_id);
+            return NGX_ERROR;
+        }
+
+        if (ctx->rest != 8) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent ping frame "
+                          "with invalid length: %uz",
+                          ctx->rest);
+            return NGX_ERROR;
+        }
+
+        if (ctx->flags & NGX_HTTP_V2_ACK_FLAG) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent ping frame with ack flag");
+            return NGX_ERROR;
+        }
+    }
+
+    for (p = b->pos; p < last; p++) {
+        ch = *p;
+
+#if 0
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "grpc ping byte: %02Xd s:%d", ch, state);
+#endif
+
+        if (state < sw_data_8) {
+            ctx->ping_data[state] = ch;
+            state++;
+
+        } else {
+            ctx->ping_data[7] = ch;
+            state = sw_start;
+
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "grpc ping");
+        }
+    }
+
+    ctx->rest -= p - b->pos;
+    ctx->frame_state = state;
+    b->pos = p;
+
+    if (ctx->rest > 0) {
+        return NGX_AGAIN;
+    }
+
+    ctx->state = ngx_http_grpc_st_start;
+
+    return ngx_http_grpc_send_ping_ack(r, ctx);
+}
+
+
+static ngx_int_t
+ngx_http_grpc_send_settings_ack(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx)
+{
+    ngx_chain_t            *cl, **ll;
+    ngx_http_grpc_frame_t  *f;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc send settings ack");
+
+    for (cl = ctx->out, ll = &ctx->out; cl; cl = cl->next) {
+        ll = &cl->next;
+    }
+
+    cl = ngx_http_grpc_get_buf(r, ctx);
+    if (cl == NULL) {
+        return NGX_ERROR;
+    }
+
+    f = (ngx_http_grpc_frame_t *) cl->buf->last;
+    cl->buf->last += sizeof(ngx_http_grpc_frame_t);
+
+    f->length_0 = 0;
+    f->length_1 = 0;
+    f->length_2 = 0;
+    f->type = NGX_HTTP_V2_SETTINGS_FRAME;
+    f->flags = NGX_HTTP_V2_ACK_FLAG;
+    f->stream_id_0 = 0;
+    f->stream_id_1 = 0;
+    f->stream_id_2 = 0;
+    f->stream_id_3 = 0;
+
+    *ll = cl;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_send_ping_ack(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx)
+{
+    ngx_chain_t            *cl, **ll;
+    ngx_http_grpc_frame_t  *f;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc send ping ack");
+
+    for (cl = ctx->out, ll = &ctx->out; cl; cl = cl->next) {
+        ll = &cl->next;
+    }
+
+    cl = ngx_http_grpc_get_buf(r, ctx);
+    if (cl == NULL) {
+        return NGX_ERROR;
+    }
+
+    f = (ngx_http_grpc_frame_t *) cl->buf->last;
+    cl->buf->last += sizeof(ngx_http_grpc_frame_t);
+
+    f->length_0 = 0;
+    f->length_1 = 0;
+    f->length_2 = 8;
+    f->type = NGX_HTTP_V2_PING_FRAME;
+    f->flags = NGX_HTTP_V2_ACK_FLAG;
+    f->stream_id_0 = 0;
+    f->stream_id_1 = 0;
+    f->stream_id_2 = 0;
+    f->stream_id_3 = 0;
+
+    cl->buf->last = ngx_copy(cl->buf->last, ctx->ping_data, 8);
+
+    *ll = cl;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_send_window_update(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx)
+{
+    size_t                  n;
+    ngx_chain_t            *cl, **ll;
+    ngx_http_grpc_frame_t  *f;
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "grpc send window update: %uz %uz",
+                   ctx->connection->recv_window, ctx->recv_window);
+
+    for (cl = ctx->out, ll = &ctx->out; cl; cl = cl->next) {
+        ll = &cl->next;
+    }
+
+    cl = ngx_http_grpc_get_buf(r, ctx);
+    if (cl == NULL) {
+        return NGX_ERROR;
+    }
+
+    f = (ngx_http_grpc_frame_t *) cl->buf->last;
+    cl->buf->last += sizeof(ngx_http_grpc_frame_t);
+
+    f->length_0 = 0;
+    f->length_1 = 0;
+    f->length_2 = 4;
+    f->type = NGX_HTTP_V2_WINDOW_UPDATE_FRAME;
+    f->flags = 0;
+    f->stream_id_0 = 0;
+    f->stream_id_1 = 0;
+    f->stream_id_2 = 0;
+    f->stream_id_3 = 0;
+
+    n = NGX_HTTP_V2_MAX_WINDOW - ctx->connection->recv_window;
+    ctx->connection->recv_window = NGX_HTTP_V2_MAX_WINDOW;
+
+    *cl->buf->last++ = (u_char) ((n >> 24) & 0xff);
+    *cl->buf->last++ = (u_char) ((n >> 16) & 0xff);
+    *cl->buf->last++ = (u_char) ((n >> 8) & 0xff);
+    *cl->buf->last++ = (u_char) (n & 0xff);
+
+    f = (ngx_http_grpc_frame_t *) cl->buf->last;
+    cl->buf->last += sizeof(ngx_http_grpc_frame_t);
+
+    f->length_0 = 0;
+    f->length_1 = 0;
+    f->length_2 = 4;
+    f->type = NGX_HTTP_V2_WINDOW_UPDATE_FRAME;
+    f->flags = 0;
+    f->stream_id_0 = (u_char) ((ctx->id >> 24) & 0xff);
+    f->stream_id_1 = (u_char) ((ctx->id >> 16) & 0xff);
+    f->stream_id_2 = (u_char) ((ctx->id >> 8) & 0xff);
+    f->stream_id_3 = (u_char) (ctx->id & 0xff);
+
+    n = NGX_HTTP_V2_MAX_WINDOW - ctx->recv_window;
+    ctx->recv_window = NGX_HTTP_V2_MAX_WINDOW;
+
+    *cl->buf->last++ = (u_char) ((n >> 24) & 0xff);
+    *cl->buf->last++ = (u_char) ((n >> 16) & 0xff);
+    *cl->buf->last++ = (u_char) ((n >> 8) & 0xff);
+    *cl->buf->last++ = (u_char) (n & 0xff);
+
+    *ll = cl;
+
+    return NGX_OK;
+}
+
+
+static ngx_chain_t *
+ngx_http_grpc_get_buf(ngx_http_request_t *r, ngx_http_grpc_ctx_t *ctx)
+{
+    ngx_buf_t    *b;
+    ngx_chain_t  *cl;
+
+    cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
+    if (cl == NULL) {
+        return NULL;
+    }
+
+    b = cl->buf;
+
+    b->tag = (ngx_buf_tag_t) &ngx_http_grpc_body_output_filter;
+    b->temporary = 1;
+    b->flush = 1;
+
+    if (b->start == NULL) {
+
+        /*
+         * each buffer is large enough to hold two window update
+         * frames in a row
+         */
+
+        b->start = ngx_palloc(r->pool, 2 * sizeof(ngx_http_grpc_frame_t) + 8);
+        if (b->start == NULL) {
+            return NULL;
+        }
+
+        b->pos = b->start;
+        b->last = b->start;
+
+        b->end = b->start + 2 * sizeof(ngx_http_grpc_frame_t) + 8;
+    }
+
+    return cl;
+}
+
+
+static ngx_http_grpc_ctx_t *
+ngx_http_grpc_get_ctx(ngx_http_request_t *r)
+{
+    ngx_http_grpc_ctx_t  *ctx;
+    ngx_http_upstream_t  *u;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_grpc_module);
+
+    if (ctx->connection == NULL) {
+        u = r->upstream;
+
+        if (ngx_http_grpc_get_connection_data(r, ctx, &u->peer) != NGX_OK) {
+            return NULL;
+        }
+    }
+
+    return ctx;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_get_connection_data(ngx_http_request_t *r,
+    ngx_http_grpc_ctx_t *ctx, ngx_peer_connection_t *pc)
+{
+    ngx_connection_t    *c;
+    ngx_pool_cleanup_t  *cln;
+
+    c = pc->connection;
+
+    if (pc->cached) {
+
+        /*
+         * for cached connections, connection data can be found
+         * in the cleanup handler
+         */
+
+        for (cln = c->pool->cleanup; cln; cln = cln->next) {
+            if (cln->handler == ngx_http_grpc_cleanup) {
+                ctx->connection = cln->data;
+                break;
+            }
+        }
+
+        if (ctx->connection == NULL) {
+            ngx_log_error(NGX_LOG_ERR, c->log, 0,
+                          "no connection data found for "
+                          "keepalive http2 connection");
+            return NGX_ERROR;
+        }
+
+        ctx->send_window = ctx->connection->init_window;
+        ctx->recv_window = NGX_HTTP_V2_MAX_WINDOW;
+
+        ctx->connection->last_stream_id += 2;
+        ctx->id = ctx->connection->last_stream_id;
+
+        return NGX_OK;
+    }
+
+    cln = ngx_pool_cleanup_add(c->pool, sizeof(ngx_http_grpc_conn_t));
+    if (cln == NULL) {
+        return NGX_ERROR;
+    }
+
+    cln->handler = ngx_http_grpc_cleanup;
+    ctx->connection = cln->data;
+
+    ctx->connection->init_window = NGX_HTTP_V2_DEFAULT_WINDOW;
+    ctx->connection->send_window = NGX_HTTP_V2_DEFAULT_WINDOW;
+    ctx->connection->recv_window = NGX_HTTP_V2_MAX_WINDOW;
+
+    ctx->send_window = NGX_HTTP_V2_DEFAULT_WINDOW;
+    ctx->recv_window = NGX_HTTP_V2_MAX_WINDOW;
+
+    ctx->id = 1;
+    ctx->connection->last_stream_id = 1;
+
+    return NGX_OK;
+}
+
+
+static void
+ngx_http_grpc_cleanup(void *data)
+{
+#if 0
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "grpc cleanup");
+#endif
+    return;
+}
+
+
+static void
+ngx_http_grpc_abort_request(ngx_http_request_t *r)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "abort grpc request");
+    return;
+}
+
+
+static void
+ngx_http_grpc_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
+{
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "finalize grpc request");
+    return;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_internal_trailers_variable(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data)
+{
+    ngx_table_elt_t  *te;
+
+    te = r->headers_in.te;
+
+    if (te == NULL) {
+        v->not_found = 1;
+        return NGX_OK;
+    }
+
+    if (ngx_strlcasestrn(te->value.data, te->value.data + te->value.len,
+                         (u_char *) "trailers", 8 - 1)
+        == NULL)
+    {
+        v->not_found = 1;
+        return NGX_OK;
+    }
+
+    v->valid = 1;
+    v->no_cacheable = 0;
+    v->not_found = 0;
+
+    v->data = (u_char *) "trailers";
+    v->len = sizeof("trailers") - 1;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_add_variables(ngx_conf_t *cf)
+{
+    ngx_http_variable_t  *var, *v;
+
+    for (v = ngx_http_grpc_vars; v->name.len; v++) {
+        var = ngx_http_add_variable(cf, &v->name, v->flags);
+        if (var == NULL) {
+            return NGX_ERROR;
+        }
+
+        var->get_handler = v->get_handler;
+        var->data = v->data;
+    }
+
+    return NGX_OK;
+}
+
+
+static void *
+ngx_http_grpc_create_loc_conf(ngx_conf_t *cf)
+{
+    ngx_http_grpc_loc_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_grpc_loc_conf_t));
+    if (conf == NULL) {
+        return NULL;
+    }
+
+    /*
+     * set by ngx_pcalloc():
+     *
+     *     conf->upstream.ignore_headers = 0;
+     *     conf->upstream.next_upstream = 0;
+     *     conf->upstream.hide_headers_hash = { NULL, 0 };
+     *     conf->upstream.ssl_name = NULL;
+     *
+     *     conf->headers_source = NULL;
+     *     conf->headers.lengths = NULL;
+     *     conf->headers.values = NULL;
+     *     conf->headers.hash = { NULL, 0 };
+     *     conf->host = { 0, NULL };
+     *     conf->host_set = 0;
+     *     conf->ssl = 0;
+     *     conf->ssl_protocols = 0;
+     *     conf->ssl_ciphers = { 0, NULL };
+     *     conf->ssl_trusted_certificate = { 0, NULL };
+     *     conf->ssl_crl = { 0, NULL };
+     *     conf->ssl_certificate = { 0, NULL };
+     *     conf->ssl_certificate_key = { 0, NULL };
+     */
+
+    conf->upstream.local = NGX_CONF_UNSET_PTR;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
+    conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
+
+    conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
+
+    conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
+    conf->upstream.pass_headers = NGX_CONF_UNSET_PTR;
+
+    conf->upstream.intercept_errors = NGX_CONF_UNSET;
+
+#if (NGX_HTTP_SSL)
+    conf->upstream.ssl_session_reuse = NGX_CONF_UNSET;
+    conf->upstream.ssl_server_name = NGX_CONF_UNSET;
+    conf->upstream.ssl_verify = NGX_CONF_UNSET;
+    conf->ssl_verify_depth = NGX_CONF_UNSET_UINT;
+    conf->ssl_passwords = NGX_CONF_UNSET_PTR;
+#endif
+
+    /* the hardcoded values */
+    conf->upstream.cyclic_temp_file = 0;
+    conf->upstream.buffering = 0;
+    conf->upstream.ignore_client_abort = 0;
+    conf->upstream.send_lowat = 0;
+    conf->upstream.bufs.num = 0;
+    conf->upstream.busy_buffers_size = 0;
+    conf->upstream.max_temp_file_size = 0;
+    conf->upstream.temp_file_write_size = 0;
+    conf->upstream.pass_request_headers = 1;
+    conf->upstream.pass_request_body = 1;
+    conf->upstream.force_ranges = 0;
+    conf->upstream.pass_trailers = 1;
+    conf->upstream.preserve_output = 1;
+
+    ngx_str_set(&conf->upstream.module, "grpc");
+
+    return conf;
+}
+
+
+static char *
+ngx_http_grpc_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_http_grpc_loc_conf_t *prev = parent;
+    ngx_http_grpc_loc_conf_t *conf = child;
+
+    ngx_int_t                  rc;
+    ngx_hash_init_t            hash;
+    ngx_http_core_loc_conf_t  *clcf;
+
+    ngx_conf_merge_ptr_value(conf->upstream.local,
+                              prev->upstream.local, NULL);
+
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
+    ngx_conf_merge_msec_value(conf->upstream.connect_timeout,
+                              prev->upstream.connect_timeout, 60000);
+
+    ngx_conf_merge_msec_value(conf->upstream.send_timeout,
+                              prev->upstream.send_timeout, 60000);
+
+    ngx_conf_merge_msec_value(conf->upstream.read_timeout,
+                              prev->upstream.read_timeout, 60000);
+
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
+    ngx_conf_merge_size_value(conf->upstream.buffer_size,
+                              prev->upstream.buffer_size,
+                              (size_t) ngx_pagesize);
+
+    ngx_conf_merge_bitmask_value(conf->upstream.ignore_headers,
+                              prev->upstream.ignore_headers,
+                              NGX_CONF_BITMASK_SET);
+
+    ngx_conf_merge_bitmask_value(conf->upstream.next_upstream,
+                              prev->upstream.next_upstream,
+                              (NGX_CONF_BITMASK_SET
+                               |NGX_HTTP_UPSTREAM_FT_ERROR
+                               |NGX_HTTP_UPSTREAM_FT_TIMEOUT));
+
+    if (conf->upstream.next_upstream & NGX_HTTP_UPSTREAM_FT_OFF) {
+        conf->upstream.next_upstream = NGX_CONF_BITMASK_SET
+                                       |NGX_HTTP_UPSTREAM_FT_OFF;
+    }
+
+    ngx_conf_merge_value(conf->upstream.intercept_errors,
+                              prev->upstream.intercept_errors, 0);
+
+#if (NGX_HTTP_SSL)
+
+    ngx_conf_merge_value(conf->upstream.ssl_session_reuse,
+                              prev->upstream.ssl_session_reuse, 1);
+
+    ngx_conf_merge_bitmask_value(conf->ssl_protocols, prev->ssl_protocols,
+                                 (NGX_CONF_BITMASK_SET|NGX_SSL_TLSv1
+                                  |NGX_SSL_TLSv1_1|NGX_SSL_TLSv1_2));
+
+    ngx_conf_merge_str_value(conf->ssl_ciphers, prev->ssl_ciphers,
+                             "DEFAULT");
+
+    if (conf->upstream.ssl_name == NULL) {
+        conf->upstream.ssl_name = prev->upstream.ssl_name;
+    }
+
+    ngx_conf_merge_value(conf->upstream.ssl_server_name,
+                              prev->upstream.ssl_server_name, 0);
+    ngx_conf_merge_value(conf->upstream.ssl_verify,
+                              prev->upstream.ssl_verify, 0);
+    ngx_conf_merge_uint_value(conf->ssl_verify_depth,
+                              prev->ssl_verify_depth, 1);
+    ngx_conf_merge_str_value(conf->ssl_trusted_certificate,
+                              prev->ssl_trusted_certificate, "");
+    ngx_conf_merge_str_value(conf->ssl_crl, prev->ssl_crl, "");
+
+    ngx_conf_merge_str_value(conf->ssl_certificate,
+                              prev->ssl_certificate, "");
+    ngx_conf_merge_str_value(conf->ssl_certificate_key,
+                              prev->ssl_certificate_key, "");
+    ngx_conf_merge_ptr_value(conf->ssl_passwords, prev->ssl_passwords, NULL);
+
+    if (conf->ssl && ngx_http_grpc_set_ssl(cf, conf) != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
+
+#endif
+
+    hash.max_size = 512;
+    hash.bucket_size = ngx_align(64, ngx_cacheline_size);
+    hash.name = "grpc_headers_hash";
+
+    if (ngx_http_upstream_hide_headers_hash(cf, &conf->upstream,
+            &prev->upstream, ngx_http_grpc_hide_headers, &hash)
+        != NGX_OK)
+    {
+        return NGX_CONF_ERROR;
+    }
+
+    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
+
+    if (clcf->noname && conf->upstream.upstream == NULL) {
+        conf->upstream.upstream = prev->upstream.upstream;
+        conf->host = prev->host;
+#if (NGX_HTTP_SSL)
+        conf->upstream.ssl = prev->upstream.ssl;
+#endif
+    }
+
+    if (clcf->lmt_excpt && clcf->handler == NULL && conf->upstream.upstream) {
+        clcf->handler = ngx_http_grpc_handler;
+    }
+
+    if (conf->headers_source == NULL) {
+        conf->headers = prev->headers;
+        conf->headers_source = prev->headers_source;
+        conf->host_set = prev->host_set;
+    }
+
+    rc = ngx_http_grpc_init_headers(cf, conf, &conf->headers,
+                                    ngx_http_grpc_headers);
+    if (rc != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
+
+    /*
+     * special handling to preserve conf->headers in the "http" section
+     * to inherit it to all servers
+     */
+
+    if (prev->headers.hash.buckets == NULL
+        && conf->headers_source == prev->headers_source)
+    {
+        prev->headers = conf->headers;
+        prev->host_set = conf->host_set;
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_init_headers(ngx_conf_t *cf, ngx_http_grpc_loc_conf_t *conf,
+    ngx_http_grpc_headers_t *headers, ngx_keyval_t *default_headers)
+{
+    u_char                       *p;
+    size_t                        size;
+    uintptr_t                    *code;
+    ngx_uint_t                    i;
+    ngx_array_t                   headers_names, headers_merged;
+    ngx_keyval_t                 *src, *s, *h;
+    ngx_hash_key_t               *hk;
+    ngx_hash_init_t               hash;
+    ngx_http_script_compile_t     sc;
+    ngx_http_script_copy_code_t  *copy;
+
+    if (headers->hash.buckets) {
+        return NGX_OK;
+    }
+
+    if (ngx_array_init(&headers_names, cf->temp_pool, 4, sizeof(ngx_hash_key_t))
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    if (ngx_array_init(&headers_merged, cf->temp_pool, 4, sizeof(ngx_keyval_t))
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    headers->lengths = ngx_array_create(cf->pool, 64, 1);
+    if (headers->lengths == NULL) {
+        return NGX_ERROR;
+    }
+
+    headers->values = ngx_array_create(cf->pool, 512, 1);
+    if (headers->values == NULL) {
+        return NGX_ERROR;
+    }
+
+    if (conf->headers_source) {
+
+        src = conf->headers_source->elts;
+        for (i = 0; i < conf->headers_source->nelts; i++) {
+
+            if (src[i].key.len == 4
+                && ngx_strncasecmp(src[i].key.data, (u_char *) "Host", 4) == 0)
+            {
+                conf->host_set = 1;
+            }
+
+            s = ngx_array_push(&headers_merged);
+            if (s == NULL) {
+                return NGX_ERROR;
+            }
+
+            *s = src[i];
+        }
+    }
+
+    h = default_headers;
+
+    while (h->key.len) {
+
+        src = headers_merged.elts;
+        for (i = 0; i < headers_merged.nelts; i++) {
+            if (ngx_strcasecmp(h->key.data, src[i].key.data) == 0) {
+                goto next;
+            }
+        }
+
+        s = ngx_array_push(&headers_merged);
+        if (s == NULL) {
+            return NGX_ERROR;
+        }
+
+        *s = *h;
+
+    next:
+
+        h++;
+    }
+
+
+    src = headers_merged.elts;
+    for (i = 0; i < headers_merged.nelts; i++) {
+
+        hk = ngx_array_push(&headers_names);
+        if (hk == NULL) {
+            return NGX_ERROR;
+        }
+
+        hk->key = src[i].key;
+        hk->key_hash = ngx_hash_key_lc(src[i].key.data, src[i].key.len);
+        hk->value = (void *) 1;
+
+        if (src[i].value.len == 0) {
+            continue;
+        }
+
+        copy = ngx_array_push_n(headers->lengths,
+                                sizeof(ngx_http_script_copy_code_t));
+        if (copy == NULL) {
+            return NGX_ERROR;
+        }
+
+        copy->code = (ngx_http_script_code_pt) ngx_http_script_copy_len_code;
+        copy->len = src[i].key.len;
+
+        size = (sizeof(ngx_http_script_copy_code_t)
+                + src[i].key.len + sizeof(uintptr_t) - 1)
+               & ~(sizeof(uintptr_t) - 1);
+
+        copy = ngx_array_push_n(headers->values, size);
+        if (copy == NULL) {
+            return NGX_ERROR;
+        }
+
+        copy->code = ngx_http_script_copy_code;
+        copy->len = src[i].key.len;
+
+        p = (u_char *) copy + sizeof(ngx_http_script_copy_code_t);
+        ngx_memcpy(p, src[i].key.data, src[i].key.len);
+
+        ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));
+
+        sc.cf = cf;
+        sc.source = &src[i].value;
+        sc.flushes = &headers->flushes;
+        sc.lengths = &headers->lengths;
+        sc.values = &headers->values;
+
+        if (ngx_http_script_compile(&sc) != NGX_OK) {
+            return NGX_ERROR;
+        }
+
+        code = ngx_array_push_n(headers->lengths, sizeof(uintptr_t));
+        if (code == NULL) {
+            return NGX_ERROR;
+        }
+
+        *code = (uintptr_t) NULL;
+
+        code = ngx_array_push_n(headers->values, sizeof(uintptr_t));
+        if (code == NULL) {
+            return NGX_ERROR;
+        }
+
+        *code = (uintptr_t) NULL;
+    }
+
+    code = ngx_array_push_n(headers->lengths, sizeof(uintptr_t));
+    if (code == NULL) {
+        return NGX_ERROR;
+    }
+
+    *code = (uintptr_t) NULL;
+
+
+    hash.hash = &headers->hash;
+    hash.key = ngx_hash_key_lc;
+    hash.max_size = 512;
+    hash.bucket_size = 64;
+    hash.name = "grpc_headers_hash";
+    hash.pool = cf->pool;
+    hash.temp_pool = NULL;
+
+    return ngx_hash_init(&hash, headers_names.elts, headers_names.nelts);
+}
+
+
+static char *
+ngx_http_grpc_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_grpc_loc_conf_t *glcf = conf;
+
+    size_t                     add;
+    ngx_str_t                 *value, *url;
+    ngx_url_t                  u;
+    ngx_http_core_loc_conf_t  *clcf;
+
+    if (glcf->upstream.upstream) {
+        return "is duplicate";
+    }
+
+    value = cf->args->elts;
+    url = &value[1];
+
+    if (ngx_strncasecmp(url->data, (u_char *) "grpc://", 7) == 0) {
+        add = 7;
+
+    } else if (ngx_strncasecmp(url->data, (u_char *) "grpcs://", 8) == 0) {
+
+#if (NGX_HTTP_SSL)
+        glcf->ssl = 1;
+
+        add = 8;
+#else
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "grpcs protocol requires SSL support");
+        return NGX_CONF_ERROR;
+#endif
+
+    } else {
+        add = 0;
+    }
+
+    ngx_memzero(&u, sizeof(ngx_url_t));
+
+    u.url.len = url->len - add;
+    u.url.data = url->data + add;
+    u.no_resolve = 1;
+
+    glcf->upstream.upstream = ngx_http_upstream_add(cf, &u, 0);
+    if (glcf->upstream.upstream == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (u.family != AF_UNIX) {
+
+        if (u.no_port) {
+            glcf->host = u.host;
+
+        } else {
+            glcf->host.len = u.host.len + 1 + u.port_text.len;
+            glcf->host.data = u.host.data;
+        }
+
+    } else {
+        ngx_str_set(&glcf->host, "localhost");
+    }
+
+    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
+
+    clcf->handler = ngx_http_grpc_handler;
+
+    if (clcf->name.data[clcf->name.len - 1] == '/') {
+        clcf->auto_redirect = 1;
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+#if (NGX_HTTP_SSL)
+
+static char *
+ngx_http_grpc_ssl_password_file(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_grpc_loc_conf_t *glcf = conf;
+
+    ngx_str_t  *value;
+
+    if (glcf->ssl_passwords != NGX_CONF_UNSET_PTR) {
+        return "is duplicate";
+    }
+
+    value = cf->args->elts;
+
+    glcf->ssl_passwords = ngx_ssl_read_password_file(cf, &value[1]);
+
+    if (glcf->ssl_passwords == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static ngx_int_t
+ngx_http_grpc_set_ssl(ngx_conf_t *cf, ngx_http_grpc_loc_conf_t *glcf)
+{
+    ngx_pool_cleanup_t  *cln;
+
+    glcf->upstream.ssl = ngx_pcalloc(cf->pool, sizeof(ngx_ssl_t));
+    if (glcf->upstream.ssl == NULL) {
+        return NGX_ERROR;
+    }
+
+    glcf->upstream.ssl->log = cf->log;
+
+    if (ngx_ssl_create(glcf->upstream.ssl, glcf->ssl_protocols, NULL)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    cln = ngx_pool_cleanup_add(cf->pool, 0);
+    if (cln == NULL) {
+        return NGX_ERROR;
+    }
+
+    cln->handler = ngx_ssl_cleanup_ctx;
+    cln->data = glcf->upstream.ssl;
+
+    if (glcf->ssl_certificate.len) {
+
+        if (glcf->ssl_certificate_key.len == 0) {
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                          "no \"grpc_ssl_certificate_key\" is defined "
+                          "for certificate \"%V\"", &glcf->ssl_certificate);
+            return NGX_ERROR;
+        }
+
+        if (ngx_ssl_certificate(cf, glcf->upstream.ssl, &glcf->ssl_certificate,
+                                &glcf->ssl_certificate_key, glcf->ssl_passwords)
+            != NGX_OK)
+        {
+            return NGX_ERROR;
+        }
+    }
+
+    if (ngx_ssl_ciphers(cf, glcf->upstream.ssl, &glcf->ssl_ciphers, 0)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    if (glcf->upstream.ssl_verify) {
+        if (glcf->ssl_trusted_certificate.len == 0) {
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                      "no grpc_ssl_trusted_certificate for grpc_ssl_verify");
+            return NGX_ERROR;
+        }
+
+        if (ngx_ssl_trusted_certificate(cf, glcf->upstream.ssl,
+                                        &glcf->ssl_trusted_certificate,
+                                        glcf->ssl_verify_depth)
+            != NGX_OK)
+        {
+            return NGX_ERROR;
+        }
+
+        if (ngx_ssl_crl(cf, glcf->upstream.ssl, &glcf->ssl_crl) != NGX_OK) {
+            return NGX_ERROR;
+        }
+    }
+
+#ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
+
+    if (SSL_CTX_set_alpn_protos(glcf->upstream.ssl->ctx,
+                                (u_char *) "\x02h2", 3)
+        != 0)
+    {
+        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
+                      "SSL_CTX_set_alpn_protos() failed");
+        return NGX_ERROR;
+    }
+
+#endif
+
+    return NGX_OK;
+}
+
+#endif
diff --git a/src/http/modules/ngx_http_log_module.c b/src/http/modules/ngx_http_log_module.c
index 917ed55..f7c4bd2 100644
--- a/src/http/modules/ngx_http_log_module.c
+++ b/src/http/modules/ngx_http_log_module.c
@@ -90,6 +90,11 @@
 } ngx_http_log_var_t;
 
 
+#define NGX_HTTP_LOG_ESCAPE_DEFAULT  0
+#define NGX_HTTP_LOG_ESCAPE_JSON     1
+#define NGX_HTTP_LOG_ESCAPE_NONE     2
+
+
 static void ngx_http_log_write(ngx_http_request_t *r, ngx_http_log_t *log,
     u_char *buf, size_t len);
 static ssize_t ngx_http_log_script_write(ngx_http_request_t *r,
@@ -126,7 +131,7 @@
     ngx_http_log_op_t *op);
 
 static ngx_int_t ngx_http_log_variable_compile(ngx_conf_t *cf,
-    ngx_http_log_op_t *op, ngx_str_t *value, ngx_uint_t json);
+    ngx_http_log_op_t *op, ngx_str_t *value, ngx_uint_t escape);
 static size_t ngx_http_log_variable_getlen(ngx_http_request_t *r,
     uintptr_t data);
 static u_char *ngx_http_log_variable(ngx_http_request_t *r, u_char *buf,
@@ -136,6 +141,10 @@
     uintptr_t data);
 static u_char *ngx_http_log_json_variable(ngx_http_request_t *r, u_char *buf,
     ngx_http_log_op_t *op);
+static size_t ngx_http_log_unescaped_variable_getlen(ngx_http_request_t *r,
+    uintptr_t data);
+static u_char *ngx_http_log_unescaped_variable(ngx_http_request_t *r,
+    u_char *buf, ngx_http_log_op_t *op);
 
 
 static void *ngx_http_log_create_main_conf(ngx_conf_t *cf);
@@ -905,7 +914,7 @@
 
 static ngx_int_t
 ngx_http_log_variable_compile(ngx_conf_t *cf, ngx_http_log_op_t *op,
-    ngx_str_t *value, ngx_uint_t json)
+    ngx_str_t *value, ngx_uint_t escape)
 {
     ngx_int_t  index;
 
@@ -916,11 +925,18 @@
 
     op->len = 0;
 
-    if (json) {
+    switch (escape) {
+    case NGX_HTTP_LOG_ESCAPE_JSON:
         op->getlen = ngx_http_log_json_variable_getlen;
         op->run = ngx_http_log_json_variable;
+        break;
 
-    } else {
+    case NGX_HTTP_LOG_ESCAPE_NONE:
+        op->getlen = ngx_http_log_unescaped_variable_getlen;
+        op->run = ngx_http_log_unescaped_variable;
+        break;
+
+    default: /* NGX_HTTP_LOG_ESCAPE_DEFAULT */
         op->getlen = ngx_http_log_variable_getlen;
         op->run = ngx_http_log_variable;
     }
@@ -1073,6 +1089,39 @@
 }
 
 
+static size_t
+ngx_http_log_unescaped_variable_getlen(ngx_http_request_t *r, uintptr_t data)
+{
+    ngx_http_variable_value_t  *value;
+
+    value = ngx_http_get_indexed_variable(r, data);
+
+    if (value == NULL || value->not_found) {
+        return 0;
+    }
+
+    value->escape = 0;
+
+    return value->len;
+}
+
+
+static u_char *
+ngx_http_log_unescaped_variable(ngx_http_request_t *r, u_char *buf,
+    ngx_http_log_op_t *op)
+{
+    ngx_http_variable_value_t  *value;
+
+    value = ngx_http_get_indexed_variable(r, op->data);
+
+    if (value == NULL || value->not_found) {
+        return buf;
+    }
+
+    return ngx_cpymem(buf, value->data, value->len);
+}
+
+
 static void *
 ngx_http_log_create_main_conf(ngx_conf_t *cf)
 {
@@ -1536,18 +1585,21 @@
     size_t               i, len;
     ngx_str_t           *value, var;
     ngx_int_t           *flush;
-    ngx_uint_t           bracket, json;
+    ngx_uint_t           bracket, escape;
     ngx_http_log_op_t   *op;
     ngx_http_log_var_t  *v;
 
-    json = 0;
+    escape = NGX_HTTP_LOG_ESCAPE_DEFAULT;
     value = args->elts;
 
     if (s < args->nelts && ngx_strncmp(value[s].data, "escape=", 7) == 0) {
         data = value[s].data + 7;
 
         if (ngx_strcmp(data, "json") == 0) {
-            json = 1;
+            escape = NGX_HTTP_LOG_ESCAPE_JSON;
+
+        } else if (ngx_strcmp(data, "none") == 0) {
+            escape = NGX_HTTP_LOG_ESCAPE_NONE;
 
         } else if (ngx_strcmp(data, "default") != 0) {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
@@ -1636,7 +1688,7 @@
                     }
                 }
 
-                if (ngx_http_log_variable_compile(cf, op, &var, json)
+                if (ngx_http_log_variable_compile(cf, op, &var, escape)
                     != NGX_OK)
                 {
                     return NGX_CONF_ERROR;
diff --git a/src/http/modules/ngx_http_memcached_module.c b/src/http/modules/ngx_http_memcached_module.c
index b681e45..82fa713 100644
--- a/src/http/modules/ngx_http_memcached_module.c
+++ b/src/http/modules/ngx_http_memcached_module.c
@@ -592,8 +592,6 @@
      *     conf->upstream.bufs.num = 0;
      *     conf->upstream.next_upstream = 0;
      *     conf->upstream.temp_path = NULL;
-     *     conf->upstream.uri = { 0, NULL };
-     *     conf->upstream.location = NULL;
      */
 
     conf->upstream.local = NGX_CONF_UNSET_PTR;
@@ -619,7 +617,6 @@
     conf->upstream.pass_request_headers = 0;
     conf->upstream.pass_request_body = 0;
     conf->upstream.force_ranges = 1;
-    conf->upstream.pass_trailers = 0;
 
     conf->index = NGX_CONF_UNSET;
     conf->gzip_flag = NGX_CONF_UNSET_UINT;
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 655355e..8c2f8cb 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -2328,36 +2328,6 @@
         return NGX_ERROR;
     }
 
-    /* provide continuous buffer for subrequests in memory */
-
-    if (r->subrequest_in_memory) {
-
-        cl = u->out_bufs;
-
-        if (cl) {
-            buf->pos = cl->buf->pos;
-        }
-
-        buf->last = buf->pos;
-
-        for (cl = u->out_bufs; cl; cl = cl->next) {
-            ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                           "http proxy in memory %p-%p %O",
-                           cl->buf->pos, cl->buf->last, ngx_buf_size(cl->buf));
-
-            if (buf->last == cl->buf->pos) {
-                buf->last = cl->buf->last;
-                continue;
-            }
-
-            buf->last = ngx_movemem(buf->last, cl->buf->pos,
-                                    cl->buf->last - cl->buf->pos);
-
-            cl->buf->pos = buf->last - (cl->buf->last - cl->buf->pos);
-            cl->buf->last = buf->last;
-        }
-    }
-
     return NGX_OK;
 }
 
@@ -2834,13 +2804,13 @@
      *     conf->upstream.cache_methods = 0;
      *     conf->upstream.temp_path = NULL;
      *     conf->upstream.hide_headers_hash = { NULL, 0 };
-     *     conf->upstream.uri = { 0, NULL };
-     *     conf->upstream.location = NULL;
      *     conf->upstream.store_lengths = NULL;
      *     conf->upstream.store_values = NULL;
      *     conf->upstream.ssl_name = NULL;
      *
      *     conf->method = NULL;
+     *     conf->location = NULL;
+     *     conf->url = { 0, NULL };
      *     conf->headers_source = NULL;
      *     conf->headers.lengths = NULL;
      *     conf->headers.values = NULL;
@@ -2916,12 +2886,11 @@
     conf->ssl_passwords = NGX_CONF_UNSET_PTR;
 #endif
 
-    /* the hardcoded values */
+    /* "proxy_cyclic_temp_file" is disabled */
     conf->upstream.cyclic_temp_file = 0;
-    conf->upstream.change_buffering = 1;
-    conf->upstream.pass_trailers = 0;
 
     conf->redirect = NGX_CONF_UNSET;
+    conf->upstream.change_buffering = 1;
 
     conf->cookie_domains = NGX_CONF_UNSET_PTR;
     conf->cookie_paths = NGX_CONF_UNSET_PTR;
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
index f217061..3fb227b 100644
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -1236,10 +1236,10 @@
 
     conf->upstream.intercept_errors = NGX_CONF_UNSET;
 
-    /* the hardcoded values */
+    /* "scgi_cyclic_temp_file" is disabled */
     conf->upstream.cyclic_temp_file = 0;
+
     conf->upstream.change_buffering = 1;
-    conf->upstream.pass_trailers = 0;
 
     ngx_str_set(&conf->upstream.module, "scgi");
 
diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index c05a5d6..a6f45b4 100644
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -2232,9 +2232,11 @@
 {
     ngx_str_t  *value = data;
 
-    if (r->upstream) {
-        value->len = r->upstream->buffer.last - r->upstream->buffer.pos;
-        value->data = r->upstream->buffer.pos;
+    if (r->headers_out.status < NGX_HTTP_SPECIAL_RESPONSE
+        && r->out && r->out->buf)
+    {
+        value->len = r->out->buf->last - r->out->buf->pos;
+        value->data = r->out->buf->pos;
     }
 
     return rc;
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index 472707b..124da4d 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -1451,10 +1451,10 @@
     conf->ssl_passwords = NGX_CONF_UNSET_PTR;
 #endif
 
-    /* the hardcoded values */
+    /* "uwsgi_cyclic_temp_file" is disabled */
     conf->upstream.cyclic_temp_file = 0;
+
     conf->upstream.change_buffering = 1;
-    conf->upstream.pass_trailers = 0;
 
     ngx_str_set(&conf->upstream.module, "uwsgi");
 
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 90c73a4..0153a15 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -399,6 +399,13 @@
       offsetof(ngx_http_core_loc_conf_t, sendfile_max_chunk),
       NULL },
 
+    { ngx_string("subrequest_output_buffer_size"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_core_loc_conf_t, subrequest_output_buffer_size),
+      NULL },
+
     { ngx_string("aio"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
       ngx_http_core_set_aio,
@@ -2237,6 +2244,12 @@
         return NGX_ERROR;
     }
 
+    if (r->subrequest_in_memory) {
+        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                      "nested in-memory subrequest \"%V\"", uri);
+        return NGX_ERROR;
+    }
+
     sr = ngx_pcalloc(r->pool, sizeof(ngx_http_request_t));
     if (sr == NULL) {
         return NGX_ERROR;
@@ -2318,6 +2331,10 @@
 
     sr->log_handler = r->log_handler;
 
+    if (sr->subrequest_in_memory) {
+        sr->filter_need_in_memory = 1;
+    }
+
     if (!sr->background) {
         if (c->data == r && r->postponed == NULL) {
             c->data = sr;
@@ -3356,6 +3373,7 @@
     clcf->internal = NGX_CONF_UNSET;
     clcf->sendfile = NGX_CONF_UNSET;
     clcf->sendfile_max_chunk = NGX_CONF_UNSET_SIZE;
+    clcf->subrequest_output_buffer_size = NGX_CONF_UNSET_SIZE;
     clcf->aio = NGX_CONF_UNSET;
     clcf->aio_write = NGX_CONF_UNSET;
 #if (NGX_THREADS)
@@ -3578,6 +3596,9 @@
     ngx_conf_merge_value(conf->sendfile, prev->sendfile, 0);
     ngx_conf_merge_size_value(conf->sendfile_max_chunk,
                               prev->sendfile_max_chunk, 0);
+    ngx_conf_merge_size_value(conf->subrequest_output_buffer_size,
+                              prev->subrequest_output_buffer_size,
+                              (size_t) ngx_pagesize);
     ngx_conf_merge_value(conf->aio, prev->aio, NGX_HTTP_AIO_OFF);
     ngx_conf_merge_value(conf->aio_write, prev->aio_write, 0);
 #if (NGX_THREADS)
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 97ba825..66c029f 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -351,6 +351,8 @@
     size_t        limit_rate_after;        /* limit_rate_after */
     size_t        sendfile_max_chunk;      /* sendfile_max_chunk */
     size_t        read_ahead;              /* read_ahead */
+    size_t        subrequest_output_buffer_size;
+                                           /* subrequest_output_buffer_size */
 
     ngx_msec_t    client_body_timeout;     /* client_body_timeout */
     ngx_msec_t    send_timeout;            /* send_timeout */
diff --git a/src/http/ngx_http_postpone_filter_module.c b/src/http/ngx_http_postpone_filter_module.c
index 55f2698..599d263 100644
--- a/src/http/ngx_http_postpone_filter_module.c
+++ b/src/http/ngx_http_postpone_filter_module.c
@@ -12,6 +12,8 @@
 
 static ngx_int_t ngx_http_postpone_filter_add(ngx_http_request_t *r,
     ngx_chain_t *in);
+static ngx_int_t ngx_http_postpone_filter_in_memory(ngx_http_request_t *r,
+    ngx_chain_t *in);
 static ngx_int_t ngx_http_postpone_filter_init(ngx_conf_t *cf);
 
 
@@ -60,6 +62,10 @@
     ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http postpone filter \"%V?%V\" %p", &r->uri, &r->args, in);
 
+    if (r->subrequest_in_memory) {
+        return ngx_http_postpone_filter_in_memory(r, in);
+    }
+
     if (r != c->data) {
 
         if (in) {
@@ -172,6 +178,78 @@
 
 
 static ngx_int_t
+ngx_http_postpone_filter_in_memory(ngx_http_request_t *r, ngx_chain_t *in)
+{
+    size_t                     len;
+    ngx_buf_t                 *b;
+    ngx_connection_t          *c;
+    ngx_http_core_loc_conf_t  *clcf;
+
+    c = r->connection;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http postpone filter in memory");
+
+    if (r->out == NULL) {
+        clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+        if (r->headers_out.content_length_n != -1) {
+            len = r->headers_out.content_length_n;
+
+            if (len > clcf->subrequest_output_buffer_size) {
+                ngx_log_error(NGX_LOG_ERR, c->log, 0,
+                              "too big subrequest response: %uz", len);
+                return NGX_ERROR;
+            }
+
+        } else {
+            len = clcf->subrequest_output_buffer_size;
+        }
+
+        b = ngx_create_temp_buf(r->pool, len);
+        if (b == NULL) {
+            return NGX_ERROR;
+        }
+
+        b->last_buf = 1;
+
+        r->out = ngx_alloc_chain_link(r->pool);
+        if (r->out == NULL) {
+            return NGX_ERROR;
+        }
+
+        r->out->buf = b;
+        r->out->next = NULL;
+    }
+
+    b = r->out->buf;
+
+    for ( /* void */ ; in; in = in->next) {
+
+        if (ngx_buf_special(in->buf)) {
+            continue;
+        }
+
+        len = in->buf->last - in->buf->pos;
+
+        if (len > (size_t) (b->end - b->last)) {
+            ngx_log_error(NGX_LOG_ERR, c->log, 0,
+                          "too big subrequest response");
+            return NGX_ERROR;
+        }
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http postpone filter in memory %uz bytes", len);
+
+        b->last = ngx_cpymem(b->last, in->buf->pos, len);
+        in->buf->pos = in->buf->last;
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
 ngx_http_postpone_filter_init(ngx_conf_t *cf)
 {
     ngx_http_next_body_filter = ngx_http_top_body_filter;
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index f68e938..b46922b 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -132,6 +132,10 @@
                  offsetof(ngx_http_headers_in_t, transfer_encoding),
                  ngx_http_process_header_line },
 
+    { ngx_string("TE"),
+                 offsetof(ngx_http_headers_in_t, te),
+                 ngx_http_process_header_line },
+
     { ngx_string("Expect"),
                  offsetof(ngx_http_headers_in_t, expect),
                  ngx_http_process_unique_header_line },
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 4352737..4f798d3 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -197,6 +197,7 @@
     ngx_table_elt_t                  *if_range;
 
     ngx_table_elt_t                  *transfer_encoding;
+    ngx_table_elt_t                  *te;
     ngx_table_elt_t                  *expect;
     ngx_table_elt_t                  *upgrade;
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 270bec1..76bd66d 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -57,8 +57,6 @@
     ngx_http_upstream_t *u);
 static ngx_int_t ngx_http_upstream_process_trailers(ngx_http_request_t *r,
     ngx_http_upstream_t *u);
-static void ngx_http_upstream_process_body_in_memory(ngx_http_request_t *r,
-    ngx_http_upstream_t *u);
 static void ngx_http_upstream_send_response(ngx_http_request_t *r,
     ngx_http_upstream_t *u);
 static void ngx_http_upstream_upgrade(ngx_http_request_t *r,
@@ -151,8 +149,6 @@
     ngx_table_elt_t *h, ngx_uint_t offset);
 static ngx_int_t ngx_http_upstream_copy_allow_ranges(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset);
-static ngx_int_t ngx_http_upstream_copy_trailer(ngx_http_request_t *r,
-    ngx_table_elt_t *h, ngx_uint_t offset);
 
 #if (NGX_HTTP_GZIP || NGX_COMPAT)
 static ngx_int_t ngx_http_upstream_copy_content_encoding(ngx_http_request_t *r,
@@ -316,10 +312,6 @@
                  ngx_http_upstream_process_charset, 0,
                  ngx_http_upstream_copy_header_line, 0, 0 },
 
-    { ngx_string("Trailer"),
-                 ngx_http_upstream_ignore_header_line, 0,
-                 ngx_http_upstream_copy_trailer, 0, 0 },
-
     { ngx_string("Transfer-Encoding"),
                  ngx_http_upstream_process_transfer_encoding, 0,
                  ngx_http_upstream_ignore_header_line, 0, 0 },
@@ -1628,6 +1620,7 @@
 
     u->request_sent = 0;
     u->request_body_sent = 0;
+    u->request_body_blocked = 0;
 
     if (rc == NGX_AGAIN) {
         ngx_add_timer(c->write, u->conf->connect_timeout);
@@ -2006,7 +1999,7 @@
     }
 
     if (rc == NGX_AGAIN) {
-        if (!c->write->ready) {
+        if (!c->write->ready || u->request_body_blocked) {
             ngx_add_timer(c->write, u->conf->send_timeout);
 
         } else if (c->write->timer_set) {
@@ -2031,7 +2024,7 @@
     }
 
     if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
-        if (ngx_tcp_push(c->fd) == NGX_ERROR) {
+        if (ngx_tcp_push(c->fd) == -1) {
             ngx_log_error(NGX_LOG_CRIT, c->log, ngx_socket_errno,
                           ngx_tcp_push_n " failed");
             ngx_http_upstream_finalize_request(r, u,
@@ -2042,7 +2035,9 @@
         c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
     }
 
-    u->write_event_handler = ngx_http_upstream_dummy_handler;
+    if (!u->conf->preserve_output) {
+        u->write_event_handler = ngx_http_upstream_dummy_handler;
+    }
 
     if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
         ngx_http_upstream_finalize_request(r, u,
@@ -2083,7 +2078,16 @@
             out = NULL;
         }
 
-        return ngx_output_chain(&u->output, out);
+        rc = ngx_output_chain(&u->output, out);
+
+        if (rc == NGX_AGAIN) {
+            u->request_body_blocked = 1;
+
+        } else {
+            u->request_body_blocked = 0;
+        }
+
+        return rc;
     }
 
     if (!u->request_sent) {
@@ -2124,6 +2128,13 @@
                 ngx_free_chain(r->pool, ln);
             }
 
+            if (rc == NGX_AGAIN) {
+                u->request_body_blocked = 1;
+
+            } else {
+                u->request_body_blocked = 0;
+            }
+
             if (rc == NGX_OK && !r->reading_body) {
                 break;
             }
@@ -2188,7 +2199,7 @@
 
 #endif
 
-    if (u->header_sent) {
+    if (u->header_sent && !u->conf->preserve_output) {
         u->write_event_handler = ngx_http_upstream_dummy_handler;
 
         (void) ngx_handle_write_event(c->write, 0);
@@ -2379,45 +2390,7 @@
         return;
     }
 
-    if (!r->subrequest_in_memory) {
-        ngx_http_upstream_send_response(r, u);
-        return;
-    }
-
-    /* subrequest content in memory */
-
-    if (u->input_filter == NULL) {
-        u->input_filter_init = ngx_http_upstream_non_buffered_filter_init;
-        u->input_filter = ngx_http_upstream_non_buffered_filter;
-        u->input_filter_ctx = r;
-    }
-
-    if (u->input_filter_init(u->input_filter_ctx) == NGX_ERROR) {
-        ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
-        return;
-    }
-
-    n = u->buffer.last - u->buffer.pos;
-
-    if (n) {
-        u->buffer.last = u->buffer.pos;
-
-        u->state->response_length += n;
-
-        if (u->input_filter(u->input_filter_ctx, n) == NGX_ERROR) {
-            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
-            return;
-        }
-    }
-
-    if (u->length == 0) {
-        ngx_http_upstream_finalize_request(r, u, 0);
-        return;
-    }
-
-    u->read_event_handler = ngx_http_upstream_process_body_in_memory;
-
-    ngx_http_upstream_process_body_in_memory(r, u);
+    ngx_http_upstream_send_response(r, u);
 }
 
 
@@ -2820,13 +2793,14 @@
 
 
 static ngx_int_t
-ngx_http_upstream_process_trailers(ngx_http_request_t *r, ngx_http_upstream_t *u)
+ngx_http_upstream_process_trailers(ngx_http_request_t *r,
+    ngx_http_upstream_t *u)
 {
-    ngx_uint_t       i;
+    ngx_uint_t        i;
     ngx_list_part_t  *part;
     ngx_table_elt_t  *h, *ho;
 
-    if (!r->expect_trailers || !u->conf->pass_trailers) {
+    if (!u->conf->pass_trailers) {
         return NGX_OK;
     }
 
@@ -2845,6 +2819,12 @@
             i = 0;
         }
 
+        if (ngx_hash_find(&u->conf->hide_headers_hash, h[i].hash,
+                          h[i].lowcase_key, h[i].key.len))
+        {
+            continue;
+        }
+
         ho = ngx_list_push(&r->headers_out.trailers);
         if (ho == NULL) {
             return NGX_ERROR;
@@ -2858,84 +2838,6 @@
 
 
 static void
-ngx_http_upstream_process_body_in_memory(ngx_http_request_t *r,
-    ngx_http_upstream_t *u)
-{
-    size_t             size;
-    ssize_t            n;
-    ngx_buf_t         *b;
-    ngx_event_t       *rev;
-    ngx_connection_t  *c;
-
-    c = u->peer.connection;
-    rev = c->read;
-
-    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "http upstream process body in memory");
-
-    if (rev->timedout) {
-        ngx_connection_error(c, NGX_ETIMEDOUT, "upstream timed out");
-        ngx_http_upstream_finalize_request(r, u, NGX_HTTP_GATEWAY_TIME_OUT);
-        return;
-    }
-
-    b = &u->buffer;
-
-    for ( ;; ) {
-
-        size = b->end - b->last;
-
-        if (size == 0) {
-            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
-                          "upstream buffer is too small to read response");
-            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
-            return;
-        }
-
-        n = c->recv(c, b->last, size);
-
-        if (n == NGX_AGAIN) {
-            break;
-        }
-
-        if (n == 0 || n == NGX_ERROR) {
-            ngx_http_upstream_finalize_request(r, u, n);
-            return;
-        }
-
-        u->state->bytes_received += n;
-        u->state->response_length += n;
-
-        if (u->input_filter(u->input_filter_ctx, n) == NGX_ERROR) {
-            ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
-            return;
-        }
-
-        if (!rev->ready) {
-            break;
-        }
-    }
-
-    if (u->length == 0) {
-        ngx_http_upstream_finalize_request(r, u, 0);
-        return;
-    }
-
-    if (ngx_handle_read_event(rev, 0) != NGX_OK) {
-        ngx_http_upstream_finalize_request(r, u, NGX_ERROR);
-        return;
-    }
-
-    if (rev->active) {
-        ngx_add_timer(rev, u->conf->read_timeout);
-
-    } else if (rev->timer_set) {
-        ngx_del_timer(rev);
-    }
-}
-
-
-static void
 ngx_http_upstream_send_response(ngx_http_request_t *r, ngx_http_upstream_t *u)
 {
     ssize_t                    n;
@@ -4449,12 +4351,6 @@
 
 #endif
 
-    if (r->subrequest_in_memory
-        && u->headers_in.status_n >= NGX_HTTP_SPECIAL_RESPONSE)
-    {
-        u->buffer.last = u->buffer.pos;
-    }
-
     r->read_event_handler = ngx_http_block_reading;
 
     if (rc == NGX_DECLINED) {
@@ -4486,13 +4382,12 @@
     }
 
     if (rc == 0) {
-        if (ngx_http_upstream_process_trailers(r, u) != NGX_OK) {
-            rc = NGX_ERROR;
-            flush = 1;
-        }
-    }
 
-    if (rc == 0) {
+        if (ngx_http_upstream_process_trailers(r, u) != NGX_OK) {
+            ngx_http_finalize_request(r, NGX_ERROR);
+            return;
+        }
+
         rc = ngx_http_send_special(r, NGX_HTTP_LAST);
 
     } else if (flush) {
@@ -5265,27 +5160,6 @@
 }
 
 
-static ngx_int_t
-ngx_http_upstream_copy_trailer(ngx_http_request_t *r,
-    ngx_table_elt_t *h, ngx_uint_t offset)
-{
-    ngx_table_elt_t  *ho;
-
-    if (!r->expect_trailers || !r->upstream->conf->pass_trailers) {
-        return NGX_OK;
-    }
-
-    ho = ngx_list_push(&r->headers_out.headers);
-    if (ho == NULL) {
-        return NGX_ERROR;
-    }
-
-    *ho = *h;
-
-    return NGX_OK;
-}
-
-
 #if (NGX_HTTP_GZIP || NGX_COMPAT)
 
 static ngx_int_t
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index 89b5fde..921a4f2 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -61,6 +61,7 @@
     ngx_msec_t                       response_time;
     ngx_msec_t                       connect_time;
     ngx_msec_t                       header_time;
+    ngx_msec_t                       queue_time;
     off_t                            response_length;
     off_t                            bytes_received;
     off_t                            bytes_sent;
@@ -187,8 +188,6 @@
     ngx_array_t                     *hide_headers;
     ngx_array_t                     *pass_headers;
 
-    ngx_flag_t                       pass_trailers;
-
     ngx_http_upstream_local_t       *local;
 
 #if (NGX_HTTP_CACHE)
@@ -224,6 +223,8 @@
     signed                           store:2;
     unsigned                         intercept_404:1;
     unsigned                         change_buffering:1;
+    unsigned                         pass_trailers:1;
+    unsigned                         preserve_output:1;
 
 #if (NGX_HTTP_SSL || NGX_COMPAT)
     ngx_ssl_t                       *ssl;
@@ -393,6 +394,7 @@
 
     unsigned                         request_sent:1;
     unsigned                         request_body_sent:1;
+    unsigned                         request_body_blocked:1;
     unsigned                         header_sent:1;
 };
 
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index 9f26a23..e886abc 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -429,7 +429,9 @@
             return NULL;
         }
 
-        v->flags &= flags | ~NGX_HTTP_VAR_WEAK;
+        if (!(flags & NGX_HTTP_VAR_WEAK)) {
+            v->flags &= ~NGX_HTTP_VAR_WEAK;
+        }
 
         return v;
     }
@@ -494,7 +496,9 @@
             return NULL;
         }
 
-        v->flags &= flags | ~NGX_HTTP_VAR_WEAK;
+        if (!(flags & NGX_HTTP_VAR_WEAK)) {
+            v->flags &= ~NGX_HTTP_VAR_WEAK;
+        }
 
         return v;
     }
diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index cea0bd9..360905c 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -55,8 +55,6 @@
 
 #define NGX_HTTP_V2_FRAME_BUFFER_SIZE            24
 
-#define NGX_HTTP_V2_DEFAULT_FRAME_SIZE           (1 << 14)
-
 #define NGX_HTTP_V2_ROOT                         (void *) -1
 
 
@@ -784,8 +782,8 @@
                    type, h2c->state.flags, h2c->state.length, h2c->state.sid);
 
     if (type >= NGX_HTTP_V2_FRAME_STATES) {
-        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
-                       "http2 frame with unknown type %ui", type);
+        ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0,
+                      "client sent frame with unknown type %ui", type);
         return ngx_http_v2_state_skip(h2c, pos, end);
     }
 
@@ -2001,9 +1999,8 @@
         return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR);
     }
 
-    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
-                   "http2 SETTINGS frame params:%uz",
-                   h2c->state.length / NGX_HTTP_V2_SETTINGS_PARAM_SIZE);
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                   "http2 SETTINGS frame");
 
     return ngx_http_v2_state_settings_params(h2c, pos, end);
 }
@@ -2170,9 +2167,8 @@
         return ngx_http_v2_state_save(h2c, pos, end, ngx_http_v2_state_ping);
     }
 
-    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
-                   "http2 PING frame ack:%ud",
-                   h2c->state.flags & NGX_HTTP_V2_ACK_FLAG ? 1 : 0);
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                   "http2 PING frame");
 
     if (h2c->state.flags & NGX_HTTP_V2_ACK_FLAG) {
         return ngx_http_v2_state_skip(h2c, pos, end);
@@ -3312,19 +3308,9 @@
             continue;
         }
 
-        switch (ch) {
-        case '\0':
-        case LF:
-        case CR:
-        case ':':
-            ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
-                          "client sent invalid header name: \"%V\"",
-                          &header->name);
-
-            return NGX_ERROR;
-        }
-
-        if (ch >= 'A' && ch <= 'Z') {
+        if (ch == '\0' || ch == LF || ch == CR || ch == ':'
+            || (ch >= 'A' && ch <= 'Z'))
+        {
             ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                           "client sent invalid header name: \"%V\"",
                           &header->name);
@@ -3338,10 +3324,7 @@
     for (i = 0; i != header->value.len; i++) {
         ch = header->value.data[i];
 
-        switch (ch) {
-        case '\0':
-        case LF:
-        case CR:
+        if (ch == '\0' || ch == LF || ch == CR) {
             ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                           "client sent header \"%V\" with "
                           "invalid value: \"%V\"",
diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h
index d89e8fe..ebd0e77 100644
--- a/src/http/v2/ngx_http_v2.h
+++ b/src/http/v2/ngx_http_v2.h
@@ -18,6 +18,7 @@
 
 #define NGX_HTTP_V2_STATE_BUFFER_SIZE    16
 
+#define NGX_HTTP_V2_DEFAULT_FRAME_SIZE   (1 << 14)
 #define NGX_HTTP_V2_MAX_FRAME_SIZE       ((1 << 24) - 1)
 
 #define NGX_HTTP_V2_INT_OCTETS           4
@@ -291,6 +292,9 @@
 ngx_int_t ngx_http_v2_send_output_queue(ngx_http_v2_connection_t *h2c);
 
 
+ngx_str_t *ngx_http_v2_get_static_name(ngx_uint_t index);
+ngx_str_t *ngx_http_v2_get_static_value(ngx_uint_t index);
+
 ngx_int_t ngx_http_v2_get_indexed_header(ngx_http_v2_connection_t *h2c,
     ngx_uint_t index, ngx_uint_t name_only);
 ngx_int_t ngx_http_v2_add_header(ngx_http_v2_connection_t *h2c,
@@ -357,4 +361,53 @@
 
 #define ngx_http_v2_write_sid  ngx_http_v2_write_uint32
 
+
+#define ngx_http_v2_indexed(i)      (128 + (i))
+#define ngx_http_v2_inc_indexed(i)  (64 + (i))
+
+#define ngx_http_v2_write_name(dst, src, len, tmp)                            \
+    ngx_http_v2_string_encode(dst, src, len, tmp, 1)
+#define ngx_http_v2_write_value(dst, src, len, tmp)                           \
+    ngx_http_v2_string_encode(dst, src, len, tmp, 0)
+
+#define NGX_HTTP_V2_ENCODE_RAW            0
+#define NGX_HTTP_V2_ENCODE_HUFF           0x80
+
+#define NGX_HTTP_V2_AUTHORITY_INDEX       1
+
+#define NGX_HTTP_V2_METHOD_INDEX          2
+#define NGX_HTTP_V2_METHOD_GET_INDEX      2
+#define NGX_HTTP_V2_METHOD_POST_INDEX     3
+
+#define NGX_HTTP_V2_PATH_INDEX            4
+#define NGX_HTTP_V2_PATH_ROOT_INDEX       4
+
+#define NGX_HTTP_V2_SCHEME_HTTP_INDEX     6
+#define NGX_HTTP_V2_SCHEME_HTTPS_INDEX    7
+
+#define NGX_HTTP_V2_STATUS_INDEX          8
+#define NGX_HTTP_V2_STATUS_200_INDEX      8
+#define NGX_HTTP_V2_STATUS_204_INDEX      9
+#define NGX_HTTP_V2_STATUS_206_INDEX      10
+#define NGX_HTTP_V2_STATUS_304_INDEX      11
+#define NGX_HTTP_V2_STATUS_400_INDEX      12
+#define NGX_HTTP_V2_STATUS_404_INDEX      13
+#define NGX_HTTP_V2_STATUS_500_INDEX      14
+
+#define NGX_HTTP_V2_ACCEPT_ENCODING_INDEX 16
+#define NGX_HTTP_V2_ACCEPT_LANGUAGE_INDEX 17
+#define NGX_HTTP_V2_CONTENT_LENGTH_INDEX  28
+#define NGX_HTTP_V2_CONTENT_TYPE_INDEX    31
+#define NGX_HTTP_V2_DATE_INDEX            33
+#define NGX_HTTP_V2_LAST_MODIFIED_INDEX   44
+#define NGX_HTTP_V2_LOCATION_INDEX        46
+#define NGX_HTTP_V2_SERVER_INDEX          54
+#define NGX_HTTP_V2_USER_AGENT_INDEX      58
+#define NGX_HTTP_V2_VARY_INDEX            59
+
+
+u_char *ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len,
+    u_char *tmp, ngx_uint_t lower);
+
+
 #endif /* _NGX_HTTP_V2_H_INCLUDED_ */
diff --git a/src/http/v2/ngx_http_v2_encode.c b/src/http/v2/ngx_http_v2_encode.c
new file mode 100644
index 0000000..ac79208
--- /dev/null
+++ b/src/http/v2/ngx_http_v2_encode.c
@@ -0,0 +1,62 @@
+
+/*
+ * Copyright (C) Nginx, Inc.
+ * Copyright (C) Valentin V. Bartenev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+static u_char *ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix,
+    ngx_uint_t value);
+
+
+u_char *
+ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, u_char *tmp,
+    ngx_uint_t lower)
+{
+    size_t  hlen;
+
+    hlen = ngx_http_v2_huff_encode(src, len, tmp, lower);
+
+    if (hlen > 0) {
+        *dst = NGX_HTTP_V2_ENCODE_HUFF;
+        dst = ngx_http_v2_write_int(dst, ngx_http_v2_prefix(7), hlen);
+        return ngx_cpymem(dst, tmp, hlen);
+    }
+
+    *dst = NGX_HTTP_V2_ENCODE_RAW;
+    dst = ngx_http_v2_write_int(dst, ngx_http_v2_prefix(7), len);
+
+    if (lower) {
+        ngx_strlow(dst, src, len);
+        return dst + len;
+    }
+
+    return ngx_cpymem(dst, src, len);
+}
+
+
+static u_char *
+ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix, ngx_uint_t value)
+{
+    if (value < prefix) {
+        *pos++ |= value;
+        return pos;
+    }
+
+    *pos++ |= prefix;
+    value -= prefix;
+
+    while (value >= 128) {
+        *pos++ = value % 128 + 128;
+        value /= 128;
+    }
+
+    *pos++ = (u_char) value;
+
+    return pos;
+}
diff --git a/src/http/v2/ngx_http_v2_filter_module.c b/src/http/v2/ngx_http_v2_filter_module.c
index a2707a4..1b19b8a 100644
--- a/src/http/v2/ngx_http_v2_filter_module.c
+++ b/src/http/v2/ngx_http_v2_filter_module.c
@@ -23,43 +23,6 @@
 #define ngx_http_v2_literal_size(h)                                           \
     (ngx_http_v2_integer_octets(sizeof(h) - 1) + sizeof(h) - 1)
 
-#define ngx_http_v2_indexed(i)      (128 + (i))
-#define ngx_http_v2_inc_indexed(i)  (64 + (i))
-
-#define ngx_http_v2_write_name(dst, src, len, tmp)                            \
-    ngx_http_v2_string_encode(dst, src, len, tmp, 1)
-#define ngx_http_v2_write_value(dst, src, len, tmp)                           \
-    ngx_http_v2_string_encode(dst, src, len, tmp, 0)
-
-#define NGX_HTTP_V2_ENCODE_RAW            0
-#define NGX_HTTP_V2_ENCODE_HUFF           0x80
-
-#define NGX_HTTP_V2_AUTHORITY_INDEX       1
-#define NGX_HTTP_V2_METHOD_GET_INDEX      2
-#define NGX_HTTP_V2_PATH_INDEX            4
-
-#define NGX_HTTP_V2_SCHEME_HTTP_INDEX     6
-#define NGX_HTTP_V2_SCHEME_HTTPS_INDEX    7
-
-#define NGX_HTTP_V2_STATUS_INDEX          8
-#define NGX_HTTP_V2_STATUS_200_INDEX      8
-#define NGX_HTTP_V2_STATUS_204_INDEX      9
-#define NGX_HTTP_V2_STATUS_206_INDEX      10
-#define NGX_HTTP_V2_STATUS_304_INDEX      11
-#define NGX_HTTP_V2_STATUS_400_INDEX      12
-#define NGX_HTTP_V2_STATUS_404_INDEX      13
-#define NGX_HTTP_V2_STATUS_500_INDEX      14
-
-#define NGX_HTTP_V2_ACCEPT_ENCODING_INDEX 16
-#define NGX_HTTP_V2_ACCEPT_LANGUAGE_INDEX 17
-#define NGX_HTTP_V2_CONTENT_LENGTH_INDEX  28
-#define NGX_HTTP_V2_CONTENT_TYPE_INDEX    31
-#define NGX_HTTP_V2_DATE_INDEX            33
-#define NGX_HTTP_V2_LAST_MODIFIED_INDEX   44
-#define NGX_HTTP_V2_LOCATION_INDEX        46
-#define NGX_HTTP_V2_SERVER_INDEX          54
-#define NGX_HTTP_V2_USER_AGENT_INDEX      58
-#define NGX_HTTP_V2_VARY_INDEX            59
 
 #define NGX_HTTP_V2_NO_TRAILERS           (ngx_http_v2_out_frame_t *) -1
 
@@ -93,10 +56,6 @@
 static ngx_int_t ngx_http_v2_push_resource(ngx_http_request_t *r,
     ngx_str_t *path, ngx_str_t *binary);
 
-static u_char *ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len,
-    u_char *tmp, ngx_uint_t lower);
-static u_char *ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix,
-    ngx_uint_t value);
 static ngx_http_v2_out_frame_t *ngx_http_v2_create_headers_frame(
     ngx_http_request_t *r, u_char *pos, u_char *end, ngx_uint_t fin);
 static ngx_http_v2_out_frame_t *ngx_http_v2_create_push_frame(
@@ -177,7 +136,7 @@
     u_char                     status, *pos, *start, *p, *tmp;
     size_t                     len, tmp_len;
     ngx_str_t                  host, location;
-    ngx_uint_t                 i, port;
+    ngx_uint_t                 i, port, fin;
     ngx_list_part_t           *part;
     ngx_table_elt_t           *header;
     ngx_connection_t          *fc;
@@ -693,7 +652,10 @@
                                       header[i].value.len, tmp);
     }
 
-    frame = ngx_http_v2_create_headers_frame(r, start, pos, r->header_only);
+    fin = r->header_only
+          || (r->headers_out.content_length_n == 0 && !r->expect_trailers);
+
+    frame = ngx_http_v2_create_headers_frame(r, start, pos, fin);
     if (frame == NULL) {
         return NGX_ERROR;
     }
@@ -1120,54 +1082,6 @@
 }
 
 
-static u_char *
-ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, u_char *tmp,
-    ngx_uint_t lower)
-{
-    size_t  hlen;
-
-    hlen = ngx_http_v2_huff_encode(src, len, tmp, lower);
-
-    if (hlen > 0) {
-        *dst = NGX_HTTP_V2_ENCODE_HUFF;
-        dst = ngx_http_v2_write_int(dst, ngx_http_v2_prefix(7), hlen);
-        return ngx_cpymem(dst, tmp, hlen);
-    }
-
-    *dst = NGX_HTTP_V2_ENCODE_RAW;
-    dst = ngx_http_v2_write_int(dst, ngx_http_v2_prefix(7), len);
-
-    if (lower) {
-        ngx_strlow(dst, src, len);
-        return dst + len;
-    }
-
-    return ngx_cpymem(dst, src, len);
-}
-
-
-static u_char *
-ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix, ngx_uint_t value)
-{
-    if (value < prefix) {
-        *pos++ |= value;
-        return pos;
-    }
-
-    *pos++ |= prefix;
-    value -= prefix;
-
-    while (value >= 128) {
-        *pos++ = value % 128 + 128;
-        value /= 128;
-    }
-
-    *pos++ = (u_char) value;
-
-    return pos;
-}
-
-
 static ngx_http_v2_out_frame_t *
 ngx_http_v2_create_headers_frame(ngx_http_request_t *r, u_char *pos,
     u_char *end, ngx_uint_t fin)
@@ -1264,9 +1178,9 @@
         cl->next = NULL;
         frame->last = cl;
 
-        ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                       "http2:%ui create HEADERS frame %p: len:%uz",
-                       stream->node->id, frame, frame->length);
+        ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "http2:%ui create HEADERS frame %p: len:%uz fin:%ui",
+                       stream->node->id, frame, frame->length, fin);
 
         return frame;
     }
@@ -1535,7 +1449,7 @@
         in = in->next;
     }
 
-    if (in == NULL) {
+    if (in == NULL || stream->out_closed) {
 
         if (stream->queued) {
             fc->write->active = 1;
diff --git a/src/http/v2/ngx_http_v2_table.c b/src/http/v2/ngx_http_v2_table.c
index 62025c4..7d49803 100644
--- a/src/http/v2/ngx_http_v2_table.c
+++ b/src/http/v2/ngx_http_v2_table.c
@@ -86,6 +86,20 @@
      / sizeof(ngx_http_v2_header_t))
 
 
+ngx_str_t *
+ngx_http_v2_get_static_name(ngx_uint_t index)
+{
+    return &ngx_http_v2_static_table[index - 1].name;
+}
+
+
+ngx_str_t *
+ngx_http_v2_get_static_value(ngx_uint_t index)
+{
+    return &ngx_http_v2_static_table[index - 1].value;
+}
+
+
 ngx_int_t
 ngx_http_v2_get_indexed_header(ngx_http_v2_connection_t *h2c, ngx_uint_t index,
     ngx_uint_t name_only)
diff --git a/src/ngx_modules.c b/src/ngx_modules.c
index bdda69a..cd1db63 100644
--- a/src/ngx_modules.c
+++ b/src/ngx_modules.c
@@ -123,6 +123,9 @@
 #if (NGX_HTTP_SCGI)
 extern ngx_module_t  ngx_http_scgi_module;
 #endif
+#if (NGX_HTTP_GRPC)
+extern ngx_module_t  ngx_http_grpc_module;
+#endif
 #if 0
 extern ngx_module_t  ngx_http_perl_module;
 #endif
@@ -403,6 +406,9 @@
 #if (NGX_HTTP_SCGI)
     &ngx_http_scgi_module,
 #endif
+#if (NGX_HTTP_GRPC)
+    &ngx_http_grpc_module,
+#endif
 #if 0
     &ngx_http_perl_module,
 #endif
@@ -685,6 +691,9 @@
 #if (NGX_HTTP_SCGI)
     "ngx_http_scgi_module",
 #endif
+#if (NGX_HTTP_GRPC)
+    "ngx_http_grpc_module",
+#endif
 #if 0
     "ngx_http_perl_module",
 #endif
@@ -1010,6 +1019,9 @@
 #if !(NGX_HTTP_GEO)
     ngx_write_stderr(" --without-http_geo_module");
 #endif
+#if !(NGX_HTTP_GRPC)
+    ngx_write_stderr(" --without-http_grpc_module");
+#endif
 #if !(NGX_HTTP_GZIP_FILTER)
     ngx_write_stderr(" --without-http_gzip_module");
 #endif
diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
index 4822e72..3d415bd 100644
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -135,7 +135,7 @@
             if (ngx_freebsd_use_tcp_nopush
                 && c->tcp_nopush == NGX_TCP_NOPUSH_UNSET)
             {
-                if (ngx_tcp_nopush(c->fd) == NGX_ERROR) {
+                if (ngx_tcp_nopush(c->fd) == -1) {
                     err = ngx_socket_errno;
 
                     /*
diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
index b44724c..5695839 100644
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -130,7 +130,7 @@
 
             if (c->tcp_nodelay == NGX_TCP_NODELAY_UNSET) {
 
-                if (ngx_tcp_nopush(c->fd) == NGX_ERROR) {
+                if (ngx_tcp_nopush(c->fd) == -1) {
                     err = ngx_socket_errno;
 
                     /*
diff --git a/src/stream/ngx_stream_geo_module.c b/src/stream/ngx_stream_geo_module.c
index 632fa5a..83f7fb4 100644
--- a/src/stream/ngx_stream_geo_module.c
+++ b/src/stream/ngx_stream_geo_module.c
@@ -341,18 +341,18 @@
 static char *
 ngx_stream_geo_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
-    char                         *rv;
-    size_t                        len;
-    ngx_str_t                    *value, name;
-    ngx_uint_t                    i;
-    ngx_conf_t                    save;
-    ngx_pool_t                   *pool;
-    ngx_array_t                  *a;
-    ngx_stream_variable_t        *var;
-    ngx_stream_geo_ctx_t         *geo;
-    ngx_stream_geo_conf_ctx_t     ctx;
+    char                       *rv;
+    size_t                      len;
+    ngx_str_t                  *value, name;
+    ngx_uint_t                  i;
+    ngx_conf_t                  save;
+    ngx_pool_t                 *pool;
+    ngx_array_t                *a;
+    ngx_stream_variable_t      *var;
+    ngx_stream_geo_ctx_t       *geo;
+    ngx_stream_geo_conf_ctx_t   ctx;
 #if (NGX_HAVE_INET6)
-    static struct in6_addr        zero;
+    static struct in6_addr      zero;
 #endif
 
     value = cf->args->elts;
@@ -409,6 +409,7 @@
 
     ctx.temp_pool = ngx_create_pool(NGX_DEFAULT_POOL_SIZE, cf->log);
     if (ctx.temp_pool == NULL) {
+        ngx_destroy_pool(pool);
         return NGX_CONF_ERROR;
     }
 
@@ -430,6 +431,10 @@
 
     *cf = save;
 
+    if (rv != NGX_CONF_OK) {
+        goto failed;
+    }
+
     if (ctx.ranges) {
 
         if (ctx.high.low && !ctx.binary_include) {
@@ -449,7 +454,7 @@
 
                 ctx.high.low[i] = ngx_palloc(cf->pool, len + sizeof(void *));
                 if (ctx.high.low[i] == NULL) {
-                    return NGX_CONF_ERROR;
+                    goto failed;
                 }
 
                 ngx_memcpy(ctx.high.low[i], a->elts, len);
@@ -475,14 +480,11 @@
         var->get_handler = ngx_stream_geo_range_variable;
         var->data = (uintptr_t) geo;
 
-        ngx_destroy_pool(ctx.temp_pool);
-        ngx_destroy_pool(pool);
-
     } else {
         if (ctx.tree == NULL) {
             ctx.tree = ngx_radix_tree_create(cf->pool, -1);
             if (ctx.tree == NULL) {
-                return NGX_CONF_ERROR;
+                goto failed;
             }
         }
 
@@ -492,7 +494,7 @@
         if (ctx.tree6 == NULL) {
             ctx.tree6 = ngx_radix_tree_create(cf->pool, -1);
             if (ctx.tree6 == NULL) {
-                return NGX_CONF_ERROR;
+                goto failed;
             }
         }
 
@@ -502,14 +504,11 @@
         var->get_handler = ngx_stream_geo_cidr_variable;
         var->data = (uintptr_t) geo;
 
-        ngx_destroy_pool(ctx.temp_pool);
-        ngx_destroy_pool(pool);
-
         if (ngx_radix32tree_insert(ctx.tree, 0, 0,
                                    (uintptr_t) &ngx_stream_variable_null_value)
             == NGX_ERROR)
         {
-            return NGX_CONF_ERROR;
+            goto failed;
         }
 
         /* NGX_BUSY is okay (default was set explicitly) */
@@ -519,12 +518,22 @@
                                     (uintptr_t) &ngx_stream_variable_null_value)
             == NGX_ERROR)
         {
-            return NGX_CONF_ERROR;
+            goto failed;
         }
 #endif
     }
 
-    return rv;
+    ngx_destroy_pool(ctx.temp_pool);
+    ngx_destroy_pool(pool);
+
+    return NGX_CONF_OK;
+
+failed:
+
+    ngx_destroy_pool(ctx.temp_pool);
+    ngx_destroy_pool(pool);
+
+    return NGX_CONF_ERROR;
 }
 
 
diff --git a/src/stream/ngx_stream_log_module.c b/src/stream/ngx_stream_log_module.c
index 466bdda..0ff7f42 100644
--- a/src/stream/ngx_stream_log_module.c
+++ b/src/stream/ngx_stream_log_module.c
@@ -89,6 +89,11 @@
 } ngx_stream_log_var_t;
 
 
+#define NGX_STREAM_LOG_ESCAPE_DEFAULT  0
+#define NGX_STREAM_LOG_ESCAPE_JSON     1
+#define NGX_STREAM_LOG_ESCAPE_NONE     2
+
+
 static void ngx_stream_log_write(ngx_stream_session_t *s, ngx_stream_log_t *log,
     u_char *buf, size_t len);
 static ssize_t ngx_stream_log_script_write(ngx_stream_session_t *s,
@@ -106,7 +111,7 @@
 static void ngx_stream_log_flush_handler(ngx_event_t *ev);
 
 static ngx_int_t ngx_stream_log_variable_compile(ngx_conf_t *cf,
-    ngx_stream_log_op_t *op, ngx_str_t *value, ngx_uint_t json);
+    ngx_stream_log_op_t *op, ngx_str_t *value, ngx_uint_t escape);
 static size_t ngx_stream_log_variable_getlen(ngx_stream_session_t *s,
     uintptr_t data);
 static u_char *ngx_stream_log_variable(ngx_stream_session_t *s, u_char *buf,
@@ -116,6 +121,10 @@
     uintptr_t data);
 static u_char *ngx_stream_log_json_variable(ngx_stream_session_t *s,
     u_char *buf, ngx_stream_log_op_t *op);
+static size_t ngx_stream_log_unescaped_variable_getlen(ngx_stream_session_t *s,
+    uintptr_t data);
+static u_char *ngx_stream_log_unescaped_variable(ngx_stream_session_t *s,
+    u_char *buf, ngx_stream_log_op_t *op);
 
 
 static void *ngx_stream_log_create_main_conf(ngx_conf_t *cf);
@@ -682,7 +691,7 @@
 
 static ngx_int_t
 ngx_stream_log_variable_compile(ngx_conf_t *cf, ngx_stream_log_op_t *op,
-    ngx_str_t *value, ngx_uint_t json)
+    ngx_str_t *value, ngx_uint_t escape)
 {
     ngx_int_t  index;
 
@@ -693,11 +702,18 @@
 
     op->len = 0;
 
-    if (json) {
+    switch (escape) {
+    case NGX_STREAM_LOG_ESCAPE_JSON:
         op->getlen = ngx_stream_log_json_variable_getlen;
         op->run = ngx_stream_log_json_variable;
+        break;
 
-    } else {
+    case NGX_STREAM_LOG_ESCAPE_NONE:
+        op->getlen = ngx_stream_log_unescaped_variable_getlen;
+        op->run = ngx_stream_log_unescaped_variable;
+        break;
+
+    default: /* NGX_STREAM_LOG_ESCAPE_DEFAULT */
         op->getlen = ngx_stream_log_variable_getlen;
         op->run = ngx_stream_log_variable;
     }
@@ -851,6 +867,40 @@
 }
 
 
+static size_t
+ngx_stream_log_unescaped_variable_getlen(ngx_stream_session_t *s,
+    uintptr_t data)
+{
+    ngx_stream_variable_value_t  *value;
+
+    value = ngx_stream_get_indexed_variable(s, data);
+
+    if (value == NULL || value->not_found) {
+        return 0;
+    }
+
+    value->escape = 0;
+
+    return value->len;
+}
+
+
+static u_char *
+ngx_stream_log_unescaped_variable(ngx_stream_session_t *s, u_char *buf,
+                                  ngx_stream_log_op_t *op)
+{
+    ngx_stream_variable_value_t  *value;
+
+    value = ngx_stream_get_indexed_variable(s, op->data);
+
+    if (value == NULL || value->not_found) {
+        return buf;
+    }
+
+    return ngx_cpymem(buf, value->data, value->len);
+}
+
+
 static void *
 ngx_stream_log_create_main_conf(ngx_conf_t *cf)
 {
@@ -1265,17 +1315,20 @@
     size_t                 i, len;
     ngx_str_t             *value, var;
     ngx_int_t             *flush;
-    ngx_uint_t             bracket, json;
+    ngx_uint_t             bracket, escape;
     ngx_stream_log_op_t   *op;
 
-    json = 0;
+    escape = NGX_STREAM_LOG_ESCAPE_DEFAULT;
     value = args->elts;
 
     if (s < args->nelts && ngx_strncmp(value[s].data, "escape=", 7) == 0) {
         data = value[s].data + 7;
 
         if (ngx_strcmp(data, "json") == 0) {
-            json = 1;
+            escape = NGX_STREAM_LOG_ESCAPE_JSON;
+
+        } else if (ngx_strcmp(data, "none") == 0) {
+            escape = NGX_STREAM_LOG_ESCAPE_NONE;
 
         } else if (ngx_strcmp(data, "default") != 0) {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
@@ -1350,7 +1403,7 @@
                     goto invalid;
                 }
 
-                if (ngx_stream_log_variable_compile(cf, op, &var, json)
+                if (ngx_stream_log_variable_compile(cf, op, &var, escape)
                     != NGX_OK)
                 {
                     return NGX_CONF_ERROR;
diff --git a/src/stream/ngx_stream_ssl_preread_module.c b/src/stream/ngx_stream_ssl_preread_module.c
index e3d11fd..62d6524 100644
--- a/src/stream/ngx_stream_ssl_preread_module.c
+++ b/src/stream/ngx_stream_ssl_preread_module.c
@@ -17,10 +17,12 @@
 typedef struct {
     size_t          left;
     size_t          size;
+    size_t          ext;
     u_char         *pos;
     u_char         *dst;
     u_char          buf[4];
     ngx_str_t       host;
+    ngx_str_t       alpn;
     ngx_log_t      *log;
     ngx_pool_t     *pool;
     ngx_uint_t      state;
@@ -32,6 +34,8 @@
     ngx_stream_ssl_preread_ctx_t *ctx, u_char *pos, u_char *last);
 static ngx_int_t ngx_stream_ssl_preread_server_name_variable(
     ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_stream_ssl_preread_alpn_protocols_variable(
+    ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_stream_ssl_preread_add_variables(ngx_conf_t *cf);
 static void *ngx_stream_ssl_preread_create_srv_conf(ngx_conf_t *cf);
 static char *ngx_stream_ssl_preread_merge_srv_conf(ngx_conf_t *cf, void *parent,
@@ -85,6 +89,9 @@
     { ngx_string("ssl_preread_server_name"), NULL,
       ngx_stream_ssl_preread_server_name_variable, 0, 0, 0 },
 
+    { ngx_string("ssl_preread_alpn_protocols"), NULL,
+      ngx_stream_ssl_preread_alpn_protocols_variable, 0, 0, 0 },
+
       ngx_stream_null_variable
 };
 
@@ -139,12 +146,14 @@
         if (p[0] != 0x16) {
             ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
                            "ssl preread: not a handshake");
+            ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module);
             return NGX_DECLINED;
         }
 
         if (p[1] != 3) {
             ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
                            "ssl preread: unsupported SSL version");
+            ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module);
             return NGX_DECLINED;
         }
 
@@ -158,6 +167,12 @@
         p += 5;
 
         rc = ngx_stream_ssl_preread_parse_record(ctx, p, p + len);
+
+        if (rc == NGX_DECLINED) {
+            ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module);
+            return NGX_DECLINED;
+        }
+
         if (rc != NGX_AGAIN) {
             return rc;
         }
@@ -175,7 +190,7 @@
 ngx_stream_ssl_preread_parse_record(ngx_stream_ssl_preread_ctx_t *ctx,
     u_char *pos, u_char *last)
 {
-    size_t   left, n, size;
+    size_t   left, n, size, ext;
     u_char  *dst, *p;
 
     enum {
@@ -192,7 +207,10 @@
         sw_ext_header,      /* extension_type, extension_data length */
         sw_sni_len,         /* SNI length */
         sw_sni_host_head,   /* SNI name_type, host_name length */
-        sw_sni_host         /* SNI host_name */
+        sw_sni_host,        /* SNI host_name */
+        sw_alpn_len,        /* ALPN length */
+        sw_alpn_proto_len,  /* ALPN protocol_name length */
+        sw_alpn_proto_data  /* ALPN protocol_name */
     } state;
 
     ngx_log_debug2(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
@@ -201,6 +219,7 @@
     state = ctx->state;
     size = ctx->size;
     left = ctx->left;
+    ext = ctx->ext;
     dst = ctx->dst;
     p = ctx->buf;
 
@@ -299,10 +318,18 @@
             break;
 
         case sw_ext_header:
-            if (p[0] == 0 && p[1] == 0) {
+            if (p[0] == 0 && p[1] == 0 && ctx->host.data == NULL) {
                 /* SNI extension */
                 state = sw_sni_len;
-                dst = NULL;
+                dst = p;
+                size = 2;
+                break;
+            }
+
+            if (p[0] == 0 && p[1] == 16 && ctx->alpn.data == NULL) {
+                /* ALPN extension */
+                state = sw_alpn_len;
+                dst = p;
                 size = 2;
                 break;
             }
@@ -313,6 +340,7 @@
             break;
 
         case sw_sni_len:
+            ext = (p[0] << 8) + p[1];
             state = sw_sni_host_head;
             dst = p;
             size = 3;
@@ -325,14 +353,21 @@
                 return NGX_DECLINED;
             }
 
-            state = sw_sni_host;
             size = (p[1] << 8) + p[2];
 
+            if (ext < 3 + size) {
+                ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                               "ssl preread: SNI format error");
+                return NGX_DECLINED;
+            }
+            ext -= 3 + size;
+
             ctx->host.data = ngx_pnalloc(ctx->pool, size);
             if (ctx->host.data == NULL) {
                 return NGX_ERROR;
             }
 
+            state = sw_sni_host;
             dst = ctx->host.data;
             break;
 
@@ -341,19 +376,77 @@
 
             ngx_log_debug1(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
                            "ssl preread: SNI hostname \"%V\"", &ctx->host);
-            return NGX_OK;
+
+            state = sw_ext;
+            dst = NULL;
+            size = ext;
+            break;
+
+        case sw_alpn_len:
+            ext = (p[0] << 8) + p[1];
+
+            ctx->alpn.data = ngx_pnalloc(ctx->pool, ext);
+            if (ctx->alpn.data == NULL) {
+                return NGX_ERROR;
+            }
+
+            state = sw_alpn_proto_len;
+            dst = p;
+            size = 1;
+            break;
+
+        case sw_alpn_proto_len:
+            size = p[0];
+
+            if (size == 0) {
+                ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                               "ssl preread: ALPN empty protocol");
+                return NGX_DECLINED;
+            }
+
+            if (ext < 1 + size) {
+                ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                               "ssl preread: ALPN format error");
+                return NGX_DECLINED;
+            }
+            ext -= 1 + size;
+
+            state = sw_alpn_proto_data;
+            dst = ctx->alpn.data + ctx->alpn.len;
+            break;
+
+        case sw_alpn_proto_data:
+            ctx->alpn.len += p[0];
+
+            ngx_log_debug1(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                           "ssl preread: ALPN protocols \"%V\"", &ctx->alpn);
+
+            if (ext) {
+                ctx->alpn.data[ctx->alpn.len++] = ',';
+
+                state = sw_alpn_proto_len;
+                dst = p;
+                size = 1;
+                break;
+            }
+
+            state = sw_ext;
+            dst = NULL;
+            size = 0;
+            break;
         }
 
         if (left < size) {
-           ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
-                          "ssl preread: failed to parse handshake");
-           return NGX_DECLINED;
+            ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+                           "ssl preread: failed to parse handshake");
+            return NGX_DECLINED;
         }
     }
 
     ctx->state = state;
     ctx->size = size;
     ctx->left = left;
+    ctx->ext = ext;
     ctx->dst = dst;
 
     return NGX_AGAIN;
@@ -384,6 +477,29 @@
 
 
 static ngx_int_t
+ngx_stream_ssl_preread_alpn_protocols_variable(ngx_stream_session_t *s,
+    ngx_variable_value_t *v, uintptr_t data)
+{
+    ngx_stream_ssl_preread_ctx_t  *ctx;
+
+    ctx = ngx_stream_get_module_ctx(s, ngx_stream_ssl_preread_module);
+
+    if (ctx == NULL) {
+        v->not_found = 1;
+        return NGX_OK;
+    }
+
+    v->valid = 1;
+    v->no_cacheable = 0;
+    v->not_found = 0;
+    v->len = ctx->alpn.len;
+    v->data = ctx->alpn.data;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
 ngx_stream_ssl_preread_add_variables(ngx_conf_t *cf)
 {
     ngx_stream_variable_t  *var, *v;
diff --git a/src/stream/ngx_stream_variables.c b/src/stream/ngx_stream_variables.c
index 95ae12b..d1526a9 100644
--- a/src/stream/ngx_stream_variables.c
+++ b/src/stream/ngx_stream_variables.c
@@ -161,7 +161,9 @@
             return NULL;
         }
 
-        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+        if (!(flags & NGX_STREAM_VAR_WEAK)) {
+            v->flags &= ~NGX_STREAM_VAR_WEAK;
+        }
 
         return v;
     }
@@ -227,7 +229,9 @@
             return NULL;
         }
 
-        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+        if (!(flags & NGX_STREAM_VAR_WEAK)) {
+            v->flags &= ~NGX_STREAM_VAR_WEAK;
+        }
 
         return v;
     }