HTTP/2: add debug logging of SETTINGS frame and its parameters.

Change-Id: If9e34b47f73cab9da1d246c942efe3045345f685
Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Reviewed-on: https://nginx-review.googlesource.com/2922
Reviewed-by: Feng Li <fengli@google.com>
Reviewed-by: Lizan Zhou <zlizan@google.com>

src/http/v2/ngx_http_v2.c

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 4910ad8..5b55a5c 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -44,6 +44,7 @@
 #define NGX_HTTP_V2_MAX_STREAMS_SETTING          0x3
 #define NGX_HTTP_V2_INIT_WINDOW_SIZE_SETTING     0x4
 #define NGX_HTTP_V2_MAX_FRAME_SIZE_SETTING       0x5
+#define NGX_HTTP_V2_HEADER_LIST_SIZE_SETTING     0x6
 
 #define NGX_HTTP_V2_FRAME_BUFFER_SIZE            24
 
@@ -1985,8 +1986,9 @@
         return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR);
     }
 
-    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
-                   "http2 SETTINGS frame ack:0");
+    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_http_v2_send_settings(h2c, 1);
 
@@ -2013,6 +2015,13 @@
 
         switch (id) {
 
+        case NGX_HTTP_V2_HEADER_TABLE_SIZE_SETTING:
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame HEADER_TABLE_SIZE:%ui "
+                           "(ignored)", value);
+            break;
+
         case NGX_HTTP_V2_ENABLE_PUSH_SETTING:
 
             if (value != 0 && value != 1) {
@@ -2024,6 +2033,16 @@
                                                     NGX_HTTP_V2_PROTOCOL_ERROR);
             }
 
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame ENABLE_PUSH:%ui "
+                           "(ignored)", value);
+            break;
+
+        case NGX_HTTP_V2_MAX_STREAMS_SETTING:
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame MAX_CONCURRENT_STREAMS:%ui "
+                           "(ignored)", value);
             break;
 
         case NGX_HTTP_V2_INIT_WINDOW_SIZE_SETTING:
@@ -2037,6 +2056,10 @@
                                                   NGX_HTTP_V2_FLOW_CTRL_ERROR);
             }
 
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame INITIAL_WINDOW_SIZE:%ui",
+                           value);
+
             if (ngx_http_v2_adjust_windows(h2c, value - h2c->init_window)
                 != NGX_OK)
             {
@@ -2060,10 +2083,25 @@
                                                     NGX_HTTP_V2_PROTOCOL_ERROR);
             }
 
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame MAX_FRAME_SIZE:%ui",
+                           value);
+
             h2c->frame_size = value;
             break;
 
+        case NGX_HTTP_V2_HEADER_LIST_SIZE_SETTING:
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame MAX_HEADER_LIST_SIZE:%ui "
+                           "(ignored)", value);
+            break;
+
         default:
+
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                           "http2 SETTINGS frame 0x%Xi:%ui "
+                           "(ignored)", id, value);
             break;
         }
 
@@ -2511,8 +2549,18 @@
     ngx_http_v2_srv_conf_t   *h2scf;
     ngx_http_v2_out_frame_t  *frame;
 
-    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
-                   "http2 send SETTINGS frame ack:%ui", ack);
+    if (ack) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                       "http2 send SETTINGS frame ack:1");
+
+        len = 0;
+
+    } else {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                       "http2 send SETTINGS frame params:3");
+
+        len = NGX_HTTP_V2_SETTINGS_PARAM_SIZE * 3;
+    }
 
     frame = ngx_palloc(h2c->pool, sizeof(ngx_http_v2_out_frame_t));
     if (frame == NULL) {
@@ -2524,8 +2572,6 @@
         return NGX_ERROR;
     }
 
-    len = ack ? 0 : (sizeof(uint16_t) + sizeof(uint32_t)) * 3;
-
     buf = ngx_create_temp_buf(h2c->pool, NGX_HTTP_V2_FRAME_HEADER_SIZE + len);
     if (buf == NULL) {
         return NGX_ERROR;
@@ -2556,15 +2602,27 @@
         h2scf = ngx_http_get_module_srv_conf(h2c->http_connection->conf_ctx,
                                              ngx_http_v2_module);
 
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                       "http2 send SETTINGS frame MAX_CONCURRENT_STREAMS:%ui",
+                       h2scf->concurrent_streams);
+
         buf->last = ngx_http_v2_write_uint16(buf->last,
                                              NGX_HTTP_V2_MAX_STREAMS_SETTING);
         buf->last = ngx_http_v2_write_uint32(buf->last,
                                              h2scf->concurrent_streams);
 
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                       "http2 send SETTINGS frame INITIAL_WINDOW_SIZE:%uz",
+                       h2scf->preread_size);
+
         buf->last = ngx_http_v2_write_uint16(buf->last,
                                          NGX_HTTP_V2_INIT_WINDOW_SIZE_SETTING);
         buf->last = ngx_http_v2_write_uint32(buf->last, h2scf->preread_size);
 
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
+                       "http2 send SETTINGS frame MAX_FRAME_SIZE:%ud",
+                       NGX_HTTP_V2_MAX_FRAME_SIZE);
+
         buf->last = ngx_http_v2_write_uint16(buf->last,
                                            NGX_HTTP_V2_MAX_FRAME_SIZE_SETTING);
         buf->last = ngx_http_v2_write_uint32(buf->last,