src/http/ngx_http_request.c

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_http.h>


static void ngx_http_init_request(ngx_event_t *ev);
static void ngx_http_process_request_line(ngx_event_t *rev);
static void ngx_http_process_request_headers(ngx_event_t *rev);
static ssize_t ngx_http_read_request_header(ngx_http_request_t *r);
static ngx_int_t ngx_http_alloc_large_header_buffer(ngx_http_request_t *r,
    ngx_uint_t request_line);

static ngx_int_t ngx_http_process_header_line(ngx_http_request_t *r,
    ngx_table_elt_t *h, ngx_uint_t offset);
static ngx_int_t ngx_http_process_unique_header_line(ngx_http_request_t *r,
    ngx_table_elt_t *h, ngx_uint_t offset);
static ngx_int_t ngx_http_process_cookie(ngx_http_request_t *r,
    ngx_table_elt_t *h, ngx_uint_t offset);

static ngx_int_t ngx_http_process_request_header(ngx_http_request_t *r);
static void ngx_http_find_virtual_server(ngx_http_request_t *r);

static void ngx_http_request_handler(ngx_event_t *ev);
static ngx_int_t ngx_http_set_write_handler(ngx_http_request_t *r);
static void ngx_http_writer(ngx_http_request_t *r);

static void ngx_http_block_read(ngx_http_request_t *r);
static void ngx_http_read_discarded_body_handler(ngx_http_request_t *r);
static ngx_int_t ngx_http_read_discarded_body(ngx_http_request_t *r);

static void ngx_http_set_keepalive(ngx_http_request_t *r);
static void ngx_http_keepalive_handler(ngx_event_t *ev);
static void ngx_http_set_lingering_close(ngx_http_request_t *r);
static void ngx_http_lingering_close_handler(ngx_event_t *ev);
static ngx_int_t ngx_http_post_action(ngx_http_request_t *r);
static void ngx_http_close_request(ngx_http_request_t *r, ngx_int_t error);
static void ngx_http_request_done(ngx_http_request_t *r, ngx_int_t error);
static void ngx_http_close_connection(ngx_connection_t *c);

static u_char *ngx_http_log_error(ngx_log_t *log, u_char *buf, size_t len);
static u_char *ngx_http_log_error_handler(ngx_http_request_t *r, u_char *buf,
    size_t len);

#if (NGX_HTTP_SSL)
static void ngx_http_ssl_handshake(ngx_event_t *rev);
static void ngx_http_ssl_handshake_handler(ngx_connection_t *c);
#endif


static char *ngx_http_client_errors[] = {

    /* NGX_HTTP_PARSE_INVALID_METHOD */
    "client sent invalid method",

    /* NGX_HTTP_PARSE_INVALID_REQUEST */
    "client sent invalid request",

    /* NGX_HTTP_PARSE_INVALID_09_METHOD */
    "client sent invalid method in HTTP/0.9 request"
};


ngx_http_header_t  ngx_http_headers_in[] = {
    { ngx_string("Host"), offsetof(ngx_http_headers_in_t, host),
                 ngx_http_process_unique_header_line },

    { ngx_string("Connection"), offsetof(ngx_http_headers_in_t, connection),
                 ngx_http_process_unique_header_line },

    { ngx_string("If-Modified-Since"),
                 offsetof(ngx_http_headers_in_t, if_modified_since),
                 ngx_http_process_header_line },

    { ngx_string("User-Agent"), offsetof(ngx_http_headers_in_t, user_agent),
                 ngx_http_process_header_line },

    { ngx_string("Referer"), offsetof(ngx_http_headers_in_t, referer),
                 ngx_http_process_header_line },

    { ngx_string("Content-Length"),
                 offsetof(ngx_http_headers_in_t, content_length),
                 ngx_http_process_unique_header_line },

    { ngx_string("Content-Type"),
                 offsetof(ngx_http_headers_in_t, content_type),
                 ngx_http_process_header_line },

    { ngx_string("Range"), offsetof(ngx_http_headers_in_t, range),
                 ngx_http_process_header_line },

    { ngx_string("Transfer-Encoding"),
                 offsetof(ngx_http_headers_in_t, transfer_encoding),
                 ngx_http_process_header_line },

#if (NGX_HTTP_GZIP)
    { ngx_string("Accept-Encoding"),
                 offsetof(ngx_http_headers_in_t, accept_encoding),
                 ngx_http_process_header_line },

    { ngx_string("Via"), offsetof(ngx_http_headers_in_t, via),
                 ngx_http_process_header_line },
#endif

    { ngx_string("Authorization"),
                 offsetof(ngx_http_headers_in_t, authorization),
                 ngx_http_process_unique_header_line },

    { ngx_string("Keep-Alive"), offsetof(ngx_http_headers_in_t, keep_alive),
                 ngx_http_process_header_line },

#if (NGX_HTTP_PROXY || NGX_HTTP_REALIP)
    { ngx_string("X-Forwarded-For"),
                 offsetof(ngx_http_headers_in_t, x_forwarded_for),
                 ngx_http_process_header_line },
#endif

#if (NGX_HTTP_REALIP)
    { ngx_string("X-Real-IP"),
                 offsetof(ngx_http_headers_in_t, x_real_ip),
                 ngx_http_process_header_line },
#endif

#if (NGX_HTTP_HEADERS)
    { ngx_string("Accept"), offsetof(ngx_http_headers_in_t, accept),
                 ngx_http_process_header_line },

    { ngx_string("Accept-Language"),
                 offsetof(ngx_http_headers_in_t, accept_language),
                 ngx_http_process_header_line },
#endif

    { ngx_string("Cookie"), 0, ngx_http_process_cookie },

    { ngx_null_string, 0, NULL }
};


void
ngx_http_init_connection(ngx_connection_t *c)
{
    ngx_event_t         *rev;
    ngx_http_log_ctx_t  *ctx;

    ctx = ngx_palloc(c->pool, sizeof(ngx_http_log_ctx_t));
    if (ctx == NULL) {
        ngx_http_close_connection(c);
        return;
    }

    ctx->client = &c->addr_text;
    ctx->request = NULL;

    c->log->connection = c->number;
    c->log->handler = ngx_http_log_error;
    c->log->data = ctx;
    c->log->action = "reading client request line";

    c->log_error = NGX_ERROR_INFO;

    rev = c->read;
    rev->handler = ngx_http_init_request;
    c->write->handler = ngx_http_empty_handler;

#if (NGX_STAT_STUB)
    ngx_atomic_fetch_add(ngx_stat_reading, 1);
#endif

    if (rev->ready) {
        /* the deferred accept(), rtsig, aio, iocp */

        if (ngx_use_accept_mutex) {
            ngx_post_event(rev, &ngx_posted_events);
            return;
        }

        ngx_http_init_request(rev);
        return;
    }

    ngx_add_timer(rev, c->listening->post_accept_timeout);

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
#if (NGX_STAT_STUB)
        ngx_atomic_fetch_add(ngx_stat_reading, -1);
#endif
        ngx_http_close_connection(c);
        return;
    }
}


static
void ngx_http_init_request(ngx_event_t *rev)
{
    ngx_uint_t                  i;
    socklen_t                   len;
    struct sockaddr_in          sin;
    ngx_connection_t           *c;
    ngx_http_request_t         *r;
    ngx_http_in_port_t         *hip;
    ngx_http_in_addr_t         *hia;
    ngx_http_log_ctx_t         *ctx;
    ngx_http_connection_t      *hc;
    ngx_http_core_srv_conf_t   *cscf;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_core_main_conf_t  *cmcf;
#if (NGX_HTTP_SSL)
    ngx_http_ssl_srv_conf_t    *sscf;
#endif

#if (NGX_STAT_STUB)
    ngx_atomic_fetch_add(ngx_stat_reading, -1);
#endif

    c = rev->data;

    if (rev->timedout) {
        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");

        ngx_http_close_connection(c);
        return;
    }

    hc = c->data;

    if (hc == NULL) {
        hc = ngx_pcalloc(c->pool, sizeof(ngx_http_connection_t));
        if (hc == NULL) {
            ngx_http_close_connection(c);
            return;
        }
    }

    r = hc->request;

    if (r) {
        ngx_memzero(r, sizeof(ngx_http_request_t));

        r->pipeline = hc->pipeline;

        if (hc->nbusy) {
            r->header_in = hc->busy[0];
        }

    } else {
        r = ngx_pcalloc(c->pool, sizeof(ngx_http_request_t));
        if (r == NULL) {
            ngx_http_close_connection(c);
            return;
        }

        hc->request = r;
    }

    c->data = r;
    r->http_connection = hc;

    c->sent = 0;
    r->signature = NGX_HTTP_MODULE;

    /* find the server configuration for the address:port */

    /* AF_INET only */

    hip = c->servers;
    hia = hip->addrs;

    r->port = hip->port;
    r->port_text = &hip->port_text;

    i = 0;

    if (hip->naddrs > 1) {

        /*
         * There are several addresses on this port and one of them
         * is the "*:port" wildcard so getsockname() is needed to determine
         * the server address.
         *
         * AcceptEx() already gave this address.
         */

#if (NGX_WIN32)
        if (c->local_sockaddr) {
            r->in_addr =
                   ((struct sockaddr_in *) c->local_sockaddr)->sin_addr.s_addr;

        } else
#endif
        {
            len = sizeof(struct sockaddr_in);
            if (getsockname(c->fd, (struct sockaddr *) &sin, &len) == -1) {
                ngx_connection_error(c, ngx_socket_errno,
                                     "getsockname() failed");
                ngx_http_close_connection(c);
                return;
            }

            r->in_addr = sin.sin_addr.s_addr;
        }

        /* the last in_port->addrs address is "*" */

        for ( /* void */ ; i < hip->naddrs - 1; i++) {
            if (hia[i].addr == r->in_addr) {
                break;
            }
        }

    } else {
        r->in_addr = hia[0].addr;
    }

    r->virtual_names = hia[i].virtual_names;

    /* the default server configuration for the address:port */
    cscf = hia[i].core_srv_conf;

    r->main_conf = cscf->ctx->main_conf;
    r->srv_conf = cscf->ctx->srv_conf;
    r->loc_conf = cscf->ctx->loc_conf;

    r->server_name = cscf->server_name;

    rev->handler = ngx_http_process_request_line;

#if (NGX_HTTP_SSL)

    sscf = ngx_http_get_module_srv_conf(r, ngx_http_ssl_module);
    if (sscf->enable) {

        if (c->ssl == NULL) {
            if (ngx_ssl_create_connection(&sscf->ssl, c, NGX_SSL_BUFFER)
                == NGX_ERROR)
            {
                ngx_http_close_connection(c);
                return;
            }

            rev->handler = ngx_http_ssl_handshake;
        }

        r->main_filter_need_in_memory = 1;
    }

#endif

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
    c->log->file = clcf->err_log->file;
    if (!(c->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
        c->log->log_level = clcf->err_log->log_level;
    }

    if (c->buffer == NULL) {
        c->buffer = ngx_create_temp_buf(c->pool,
                                        cscf->client_header_buffer_size);
        if (c->buffer == NULL) {
            ngx_http_close_connection(c);
            return;
        }
    }

    if (r->header_in == NULL) {
        r->header_in = c->buffer;
    }

    r->pool = ngx_create_pool(cscf->request_pool_size, c->log);
    if (r->pool == NULL) {
        ngx_http_close_connection(c);
        return;
    }


    if (ngx_list_init(&r->headers_out.headers, r->pool, 20,
                      sizeof(ngx_table_elt_t))
        == NGX_ERROR)
    {
        ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
        return;
    }

    r->ctx = ngx_pcalloc(r->pool, sizeof(void *) * ngx_http_max_module);
    if (r->ctx == NULL) {
        ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
        return;
    }

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    r->variables = ngx_pcalloc(r->pool, cmcf->variables.nelts
                                        * sizeof(ngx_http_variable_value_t));
    if (r->variables == NULL) {
        ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
        return;
    }

    c->single_connection = 1;
    c->destroyed = 0;

    r->connection = c;

    r->main = r;

    r->start_time = ngx_time();

    r->headers_in.content_length_n = -1;
    r->headers_in.keep_alive_n = -1;
    r->headers_out.content_length_n = -1;
    r->headers_out.last_modified_time = -1;

    r->http_state = NGX_HTTP_READING_REQUEST_STATE;

    ctx = c->log->data;
    ctx->request = r;
    r->log_handler = ngx_http_log_error_handler;

#if (NGX_STAT_STUB)
    ngx_atomic_fetch_add(ngx_stat_reading, 1);
    r->stat_reading = 1;
    ngx_atomic_fetch_add(ngx_stat_requests, 1);
#endif

    rev->handler(rev);
}


#if (NGX_HTTP_SSL)

static void
ngx_http_ssl_handshake(ngx_event_t *rev)
{
    u_char               buf[1];
    ssize_t              n;
    ngx_int_t            rc;
    ngx_connection_t    *c;
    ngx_http_request_t  *r;

    c = rev->data;
    r = c->data;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                   "http check ssl handshake");

    if (rev->timedout) {
        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
        c->timedout = 1;
        ngx_http_close_request(r, NGX_HTTP_REQUEST_TIME_OUT);
        return;
    }

    n = recv(c->fd, (char *) buf, 1, MSG_PEEK);

    if (n == -1 && ngx_socket_errno == NGX_EAGAIN) {
        return;
    }

    if (n == 1) {
        if (buf[0] == 0x80 /* SSLv2 */ || buf[0] == 0x16 /* SSLv3/TLSv1 */) {
            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                           "https ssl handshake: 0x%02Xd", buf[0]);

            rc = ngx_ssl_handshake(c);

            if (rc == NGX_AGAIN) {
                c->ssl->handler = ngx_http_ssl_handshake_handler;
                return;
            }

            ngx_http_ssl_handshake_handler(c);

            return;

        } else {
            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                           "plain http");

            r->plain_http = 1;
        }
    }

    rev->handler = ngx_http_process_request_line;
    ngx_http_process_request_line(rev);
}


static void
ngx_http_ssl_handshake_handler(ngx_connection_t *c)
{
    ngx_http_request_t  *r;

    if (c->ssl->handshaked) {

        /*
         * The majority of browsers do not send the "close notify" alert.
         * Among them are MSIE, old Mozilla, Netscape 4, Konqueror,
         * and Links.  And what is more, MSIE ignores the server's alert.
         *
         * Opera and recent Mozilla send the alert.
         */

        c->ssl->no_wait_shutdown = 1;

        c->read->handler = ngx_http_process_request_line;
        /* STUB: epoll edge */ c->write->handler = ngx_http_empty_handler;

        ngx_http_process_request_line(c->read);

        return;
    }

    r = c->data;

    ngx_http_close_request(r, NGX_HTTP_BAD_REQUEST);

    return;
}


#endif


static void
ngx_http_process_request_line(ngx_event_t *rev)
{
    ssize_t              n;
    ngx_int_t            rc, rv;
    ngx_connection_t    *c;
    ngx_http_request_t  *r;
    ngx_http_log_ctx_t  *ctx;

    c = rev->data;
    r = c->data;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                   "http process request line");

    if (rev->timedout) {
        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
        c->timedout = 1;
        ngx_http_close_request(r, NGX_HTTP_REQUEST_TIME_OUT);
        return;
    }

    rc = NGX_AGAIN;

    for ( ;; ) {

        if (rc == NGX_AGAIN) {
            n = ngx_http_read_request_header(r);

            if (n == NGX_AGAIN || n == NGX_ERROR) {
                return;
            }
        }

        rc = ngx_http_parse_request_line(r, r->header_in);

        if (rc == NGX_OK) {

            /* the request line has been parsed successfully */

            r->request_line.len = r->request_end - r->request_start;
            r->request_line.data = r->request_start;


            if (r->args_start) {
                r->uri.len = r->args_start - 1 - r->uri_start;
            } else {
                r->uri.len = r->uri_end - r->uri_start;
            }


            if (r->complex_uri || r->quoted_uri) {

                r->uri.data = ngx_palloc(r->pool, r->uri.len + 1);
                if (r->uri.data == NULL) {
                    ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                    return;
                }

                rc = ngx_http_parse_complex_uri(r);

                if (rc == NGX_HTTP_PARSE_INVALID_REQUEST) {
                    ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                  "client sent invalid request");
                    ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
                    return;
                }

            } else {
                r->uri.data = r->uri_start;
            }


            r->unparsed_uri.len = r->uri_end - r->uri_start;
            r->unparsed_uri.data = r->uri_start;


            r->method_name.len = r->method_end - r->request_start + 1;
            r->method_name.data = r->request_line.data;


            if (r->http_protocol.data) {
                r->http_protocol.len = r->request_end - r->http_protocol.data;
            }


            if (r->uri_ext) {
                if (r->args_start) {
                    r->exten.len = r->args_start - 1 - r->uri_ext;
                } else {
                    r->exten.len = r->uri_end - r->uri_ext;
                }

                r->exten.data = r->uri_ext;
            }


            if (r->args_start && r->uri_end > r->args_start) {
                r->args.len = r->uri_end - r->args_start;
                r->args.data = r->args_start;
            }


            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http request line: \"%V\"", &r->request_line);

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http uri: \"%V\"", &r->uri);

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http args: \"%V\"", &r->args);

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http exten: \"%V\"", &r->exten);

            if (r->http_version < NGX_HTTP_VERSION_10) {

                if (rev->timer_set) {
                    ngx_del_timer(rev);
                }

#if (NGX_STAT_STUB)
                ngx_atomic_fetch_add(ngx_stat_reading, -1);
                r->stat_reading = 0;
                ngx_atomic_fetch_add(ngx_stat_writing, 1);
                r->stat_writing = 1;
#endif

                rev->handler = ngx_http_request_handler;
                c->write->handler = ngx_http_request_handler;
                r->read_event_handler = ngx_http_block_read;

                ngx_http_handler(r);

                return;
            }


            if (ngx_list_init(&r->headers_in.headers, r->pool, 20,
                              sizeof(ngx_table_elt_t))
                == NGX_ERROR)
            {
                ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                return;
            }


            if (ngx_array_init(&r->headers_in.cookies, r->pool, 2,
                               sizeof(ngx_table_elt_t *))
                == NGX_ERROR)
            {
                ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                return;
            }

            c->log->action = "reading client request headers";

            rev->handler = ngx_http_process_request_headers;
            ngx_http_process_request_headers(rev);

            return;
        }

        if (rc != NGX_AGAIN) {

            /* there was error while a request line parsing */

            ngx_log_error(NGX_LOG_INFO, c->log, 0,
                          ngx_http_client_errors[rc - NGX_HTTP_CLIENT_ERROR]);
            ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
            return;
        }

        /* NGX_AGAIN: a request line parsing is still incomplete */

        if (r->header_in->pos == r->header_in->end) {

            rv = ngx_http_alloc_large_header_buffer(r, 1);

            if (rv == NGX_ERROR) {
                ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                return;
            }

            if (rv == NGX_DECLINED) {
                ctx = c->log->data;
                ctx->request = r;

                r->request_line.len = r->header_in->end - r->request_start;
                r->request_line.data = r->request_start;

                ngx_log_error(NGX_LOG_INFO, c->log, 0,
                              "client sent too long URI");
                ngx_http_finalize_request(r, NGX_HTTP_REQUEST_URI_TOO_LARGE);
                return;
            }
        }
    }
}


static void
ngx_http_process_request_headers(ngx_event_t *rev)
{
    ssize_t                     n;
    ngx_int_t                   rc, rv;
    ngx_uint_t                  key;
    ngx_str_t                   header;
    ngx_table_elt_t            *h;
    ngx_connection_t           *c;
    ngx_http_header_t          *hh;
    ngx_http_request_t         *r;
    ngx_http_core_srv_conf_t   *cscf;
    ngx_http_core_main_conf_t  *cmcf;

    c = rev->data;
    r = c->data;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                   "http process request header line");

    if (rev->timedout) {
        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
        c->timedout = 1;
        ngx_http_close_request(r, NGX_HTTP_REQUEST_TIME_OUT);
        return;
    }

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);
    cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
    hh = (ngx_http_header_t *) cmcf->headers_in_hash.buckets;

    rc = NGX_AGAIN;

    for ( ;; ) {

        if (rc == NGX_AGAIN) {

            if (r->header_in->pos == r->header_in->end) {

                rv = ngx_http_alloc_large_header_buffer(r, 0);

                if (rv == NGX_ERROR) {
                    ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                    return;
                }

                if (rv == NGX_DECLINED) {
                    header.len = r->header_in->end - r->header_name_start;
                    header.data = r->header_name_start;

                    if (header.len > NGX_MAX_ERROR_STR - 300) {
                        header.len = NGX_MAX_ERROR_STR - 300;
                        header.data[header.len++] = '.';
                        header.data[header.len++] = '.';
                        header.data[header.len++] = '.';
                    }

                    ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                  "client sent too long header line: \"%V\"",
                                  &header);
                    ngx_http_close_request(r, NGX_HTTP_BAD_REQUEST);
                    return;
                }
            }

            n = ngx_http_read_request_header(r);

            if (n == NGX_AGAIN || n == NGX_ERROR) {
                return;
            }
        }

        rc = ngx_http_parse_header_line(r, r->header_in);

        if (rc == NGX_OK) {

            if (r->invalid_header && cscf->ignore_invalid_headers) {

                /* there was error while a header line parsing */

                header.len = r->header_end - r->header_name_start;
                header.data = r->header_name_start;

                ngx_log_error(NGX_LOG_INFO, c->log, 0,
                              "client sent invalid header line: \"%V\"",
                              &header);
                continue;
            }

            /* a header line has been parsed successfully */

            h = ngx_list_push(&r->headers_in.headers);
            if (h == NULL) {
                ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                return;
            }

            h->hash = r->header_hash;

            h->key.len = r->header_name_end - r->header_name_start;
            h->key.data = r->header_name_start;
            h->key.data[h->key.len] = '\0';

            h->value.len = r->header_end - r->header_start;
            h->value.data = r->header_start;
            h->value.data[h->value.len] = '\0';

            key = h->hash % cmcf->headers_in_hash.hash_size;

            if (hh[key].name.len == h->key.len
                && ngx_strcasecmp(hh[key].name.data, h->key.data) == 0)
            {
                if (hh[key].handler(r, h, hh[key].offset) != NGX_OK) {
                    return;
                }
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http header: \"%V: %V\"",
                           &h->key, &h->value);

            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,
                           "http header done");

            r->request_length += r->header_in->pos - r->header_in->start;

            r->http_state = NGX_HTTP_PROCESS_REQUEST_STATE;

            rc = ngx_http_process_request_header(r);

            if (rc != NGX_OK) {
                return;
            }

            if (rev->timer_set) {
                ngx_del_timer(rev);
            }

#if (NGX_STAT_STUB)
            ngx_atomic_fetch_add(ngx_stat_reading, -1);
            r->stat_reading = 0;
            ngx_atomic_fetch_add(ngx_stat_writing, 1);
            r->stat_writing = 1;
#endif

            rev->handler = ngx_http_request_handler;
            c->write->handler = ngx_http_request_handler;
            r->read_event_handler = ngx_http_block_read;

            ngx_http_handler(r);

            return;
        }

        if (rc == NGX_AGAIN) {

            /* a header line parsing is still not complete */

            continue;
        }

        /* rc == NGX_HTTP_PARSE_INVALID_HEADER: "\r" is not followed by "\n" */

        header.len = r->header_end - r->header_name_start;
        header.data = r->header_name_start;
        ngx_log_error(NGX_LOG_INFO, c->log, 0,
                      "client sent invalid header line: \"%V\\r...\"",
                      &header);
        ngx_http_close_request(r, NGX_HTTP_BAD_REQUEST);
        return;
    }
}


static ssize_t
ngx_http_read_request_header(ngx_http_request_t *r)
{
    ssize_t                    n;
    ngx_event_t               *rev;
    ngx_http_core_srv_conf_t  *cscf;

    rev = r->connection->read;

    n = r->header_in->last - r->header_in->pos;

    if (n > 0) {
        return n;
    }

    if (rev->ready) {
        n = r->connection->recv(r->connection, r->header_in->last,
                                r->header_in->end - r->header_in->last);
    } else {
        n = NGX_AGAIN;
    }

    if (n == NGX_AGAIN) {
        if (!r->header_timeout_set) {
            cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
            ngx_add_timer(rev, cscf->client_header_timeout);
            r->header_timeout_set = 1;
        }

        if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
            ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
            return NGX_ERROR;
        }

        return NGX_AGAIN;
    }

    if (n == 0) {
        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                      "client closed prematurely connection");
    }

    if (n == 0 || n == NGX_ERROR) {
        ngx_http_close_request(r, NGX_HTTP_BAD_REQUEST);
        return NGX_ERROR;
    }

    r->header_in->last += n;

    return n;
}


static ngx_int_t
ngx_http_alloc_large_header_buffer(ngx_http_request_t *r,
    ngx_uint_t request_line)
{
    u_char                    *old, *new;
    ngx_buf_t                 *b;
    ngx_http_connection_t     *hc;
    ngx_http_core_srv_conf_t  *cscf;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http alloc large header buffer");

    if (request_line && r->state == 0) {

        /* the client fills up the buffer with "\r\n" */

        r->request_length += r->header_in->end - r->header_in->start;

        r->header_in->pos = r->header_in->start;
        r->header_in->last = r->header_in->start;

        return NGX_OK;
    }

    old = request_line ? r->request_start : r->header_name_start;

    cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);

    if (r->state != 0
        && (size_t) (r->header_in->pos - old)
                                     >= cscf->large_client_header_buffers.size)
    {
        return NGX_DECLINED;
    }

    hc = r->http_connection;

    if (hc->nfree) {
        b = hc->free[--hc->nfree];

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http large header free: %p %uz",
                       b->pos, b->end - b->last);

    } else if (hc->nbusy < cscf->large_client_header_buffers.num) {

        if (hc->busy == NULL) {
            hc->busy = ngx_palloc(r->connection->pool,
                  cscf->large_client_header_buffers.num * sizeof(ngx_buf_t *));
            if (hc->busy == NULL) {
                return NGX_ERROR;
            }
        }

        b = ngx_create_temp_buf(r->connection->pool,
                                cscf->large_client_header_buffers.size);
        if (b == NULL) {
            return NGX_ERROR;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http large header alloc: %p %uz",
                       b->pos, b->end - b->last);

    } else {
        return NGX_DECLINED;
    }

    hc->busy[hc->nbusy++] = b;

    if (r->state == 0) {
        /*
         * r->state == 0 means that a header line was parsed successfully
         * and we do not need to copy incomplete header line and
         * to relocate the parser header pointers
         */

        r->request_length += r->header_in->end - r->header_in->start;

        r->header_in = b;

        return NGX_OK;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http large header copy: %d", r->header_in->pos - old);

    r->request_length += old - r->header_in->start;

    new = b->start;

    ngx_memcpy(new, old, r->header_in->pos - old);

    b->pos = new + (r->header_in->pos - old);
    b->last = new + (r->header_in->pos - old);

    if (request_line) {
        r->request_start = new;

        if (r->request_end) {
            r->request_end = new + (r->request_end - old);
        }

        r->method_end = new + (r->method_end - old);

        r->uri_start = new + (r->uri_start - old);
        r->uri_end = new + (r->uri_end - old);

        if (r->schema_start) {
            r->schema_start = new + (r->schema_start - old);
            r->schema_end = new + (r->schema_end - old);
        }

        if (r->host_start) {
            r->host_start = new + (r->host_start - old);
            r->host_end = new + (r->host_end - old);
        }

        if (r->port_start) {
            r->port_start = new + (r->port_start - old);
            r->port_end = new + (r->port_end - old);
        }

        if (r->uri_ext) {
            r->uri_ext = new + (r->uri_ext - old);
        }

        if (r->args_start) {
            r->args_start = new + (r->args_start - old);
        }

    } else {
        r->header_name_start = new;
        r->header_name_end = new + (r->header_name_end - old);
        r->header_start = new + (r->header_start - old);
        r->header_end = new + (r->header_end - old);
    }

    r->header_in = b;

    return NGX_OK;
}


static ngx_int_t
ngx_http_process_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
    ngx_uint_t offset)
{
    ngx_table_elt_t  **ph;

    ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);

    if (*ph == NULL) {
        *ph = h;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_process_unique_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
    ngx_uint_t offset)
{
    ngx_table_elt_t  **ph;

    ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);

    if (*ph == NULL) {
        *ph = h;
        return NGX_OK;
    }

    ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                  "client sent duplicate header line: \"%V: %V\"",
                  &h->key, &h->value);

    ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);

    return NGX_ERROR;
}


static ngx_int_t
ngx_http_process_cookie(ngx_http_request_t *r, ngx_table_elt_t *h,
    ngx_uint_t offset)
{
    ngx_table_elt_t  **cookie;

    cookie = ngx_array_push(&r->headers_in.cookies);
    if (cookie) {
        *cookie = h;
        return NGX_OK;
    }

    ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);

    return NGX_ERROR;
}


static ngx_int_t
ngx_http_process_request_header(ngx_http_request_t *r)
{
    size_t   len;
    u_char  *ua, *user_agent, ch;

    if (r->headers_in.host) {
        for (len = 0; len < r->headers_in.host->value.len; len++) {
            ch = r->headers_in.host->value.data[len];

            if (ch == ':') {
                break;
            }

            r->headers_in.host->value.data[len] = ngx_tolower(ch);
        }

        if (r->headers_in.host->value.data[len - 1] == '.') {
            len--;
        }

        r->headers_in.host_name_len = len;

        ngx_http_find_virtual_server(r);

    } else {
        if (r->http_version > NGX_HTTP_VERSION_10) {
            ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                       "client sent HTTP/1.1 request without \"Host\" header");
            ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
            return NGX_ERROR;
        }

        r->headers_in.host_name_len = 0;
    }

    if (r->headers_in.content_length) {
        r->headers_in.content_length_n =
                            ngx_atosz(r->headers_in.content_length->value.data,
                                      r->headers_in.content_length->value.len);

        if (r->headers_in.content_length_n == NGX_ERROR) {
            ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                          "client sent invalid \"Content-Length\" header");
            ngx_http_finalize_request(r, NGX_HTTP_LENGTH_REQUIRED);
            return NGX_ERROR;
        }
    }

    if (r->method == NGX_HTTP_POST && r->headers_in.content_length_n == -1) {
        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                  "client sent POST method without \"Content-Length\" header");
        ngx_http_finalize_request(r, NGX_HTTP_LENGTH_REQUIRED);
        return NGX_ERROR;
    }

    if (r->headers_in.transfer_encoding
        && ngx_strstr(r->headers_in.transfer_encoding->value.data, "chunked"))
    {
        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                      "client sent \"Transfer-Encoding: chunked\" header");
        ngx_http_finalize_request(r, NGX_HTTP_LENGTH_REQUIRED);
        return NGX_ERROR;
    }

    if (r->plain_http) {
        ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                      "client sent plain HTTP request to HTTPS port");
        ngx_http_finalize_request(r, NGX_HTTP_TO_HTTPS);
        return NGX_ERROR;
    }

    if (r->headers_in.connection) {
        if (r->headers_in.connection->value.len == 5
            && ngx_strcasecmp(r->headers_in.connection->value.data, "close")
               == 0)
        {
            r->headers_in.connection_type = NGX_HTTP_CONNECTION_CLOSE;

        } else if (r->headers_in.connection->value.len == 10
                   && ngx_strcasecmp(r->headers_in.connection->value.data,
                                     "keep-alive") == 0)
        {
            r->headers_in.connection_type = NGX_HTTP_CONNECTION_KEEP_ALIVE;

            if (r->headers_in.keep_alive) {
                r->headers_in.keep_alive_n =
                                ngx_atotm(r->headers_in.keep_alive->value.data,
                                          r->headers_in.keep_alive->value.len);
            }
        }
    }

    if (r->headers_in.user_agent) {

        /*
         * check some widespread browsers while the headers are still
         * in CPU cache
         */

        user_agent = r->headers_in.user_agent->value.data;

        ua = (u_char *) ngx_strstr(user_agent, "MSIE");

        if (ua && ua + 8 < user_agent + r->headers_in.user_agent->value.len) {

            r->headers_in.msie = 1;

            if (ua[4] == ' ' && ua[5] == '4' && ua[6] == '.') {
                r->headers_in.msie4 = 1;
            }

#if 0
            /* MSIE ignores the SSL "close notify" alert */
            if (c->ssl) {
                c->ssl->no_send_shutdown = 1;
            }
#endif
        }

        if (ngx_strstr(user_agent, "Opera")) {
            r->headers_in.opera = 1;
            r->headers_in.msie = 0;
            r->headers_in.msie4 = 0;
        }

        if (!r->headers_in.msie && !r->headers_in.opera) {

            if (ngx_strstr(user_agent, "Gecko/")) {
                r->headers_in.gecko = 1;

            } else if (ngx_strstr(user_agent, "Konqueror")) {
                r->headers_in.konqueror = 1;
            }
        }
    }

    return NGX_OK;
}


static void
ngx_http_find_virtual_server(ngx_http_request_t *r)
{
    size_t                     len;
    u_char                    *host;
    ngx_http_virtual_names_t  *vn;
    ngx_http_core_loc_conf_t  *clcf;
    ngx_http_core_srv_conf_t  *cscf;

    vn = r->virtual_names;

    if (vn == NULL) {
        return;
    }

    host = r->headers_in.host->value.data;
    len = r->headers_in.host_name_len;

    /* STUB: ngx_hash_key() here is STUB */

    if (vn->hash.buckets) {
        cscf = ngx_hash_find(&vn->hash, ngx_hash_key(host, len), host, len);
        if (cscf) {
            goto found;
        }
    }

    if (vn->dns_wildcards && vn->dns_wildcards->hash.buckets) {
        cscf = ngx_hash_find_wildcard(vn->dns_wildcards, host, len);

        if (cscf) {
            goto found;
        }
    }

    return;

found:

    r->server_name.len = len;
    r->server_name.data = host;

    r->srv_conf = cscf->ctx->srv_conf;
    r->loc_conf = cscf->ctx->loc_conf;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
    r->connection->log->file = clcf->err_log->file;

    if (!(r->connection->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
        r->connection->log->log_level = clcf->err_log->log_level;
    }

    return;
}


static void
ngx_http_request_handler(ngx_event_t *ev)
{
    ngx_connection_t    *c;
    ngx_http_request_t  *r;

    c = ev->data;
    r = c->data;

    if (ev->write) {
        r->write_event_handler(r);

    } else {
        r->read_event_handler(r);
    }
}


void
ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
{
    ngx_http_request_t        *pr;
    ngx_http_core_loc_conf_t  *clcf;

    if (rc == NGX_DONE) {
        /* the request pool may be already destroyed */
        return;
    }

    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http finalize request: %d, \"%V?%V\"",
                   rc, &r->uri, &r->args);

    if (rc == NGX_ERROR
        || rc == NGX_HTTP_REQUEST_TIME_OUT
        || r->connection->error)
    {
        if (ngx_http_post_action(r) == NGX_OK) {
            return;
        }

        ngx_http_close_request(r, 0);
        return;
    }

    if (rc >= NGX_HTTP_SPECIAL_RESPONSE || rc == NGX_HTTP_NO_CONTENT) {

        if (rc == NGX_HTTP_CLOSE) {
            ngx_http_close_request(r, rc);
            return;
        }

        if (r == r->main) {
            if (r->connection->read->timer_set) {
                ngx_del_timer(r->connection->read);
            }

            if (r->connection->write->timer_set) {
                ngx_del_timer(r->connection->write);
            }
        }

        ngx_http_finalize_request(r, ngx_http_special_response_handler(r, rc));

        return;
    }

    if (r != r->main || rc == NGX_AGAIN) {
        if (ngx_http_set_write_handler(r) != NGX_OK) {
            return;
        }
    }

    r->done = 1;

    if (r != r->connection->data) {
        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http finalize non-active request: \"%V?%V\"",
                       &r->uri, &r->args);
        return;
    }

    if (r != r->main) {

        pr = r->parent;

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http parent request: \"%V?%V\"", &pr->uri, &pr->args);

        if (rc != NGX_AGAIN) {
            r->connection->data = pr;
        }

        if (pr->postponed) {

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http request: \"%V?%V\" has postponed",
                           &pr->uri, &pr->args);

            if (rc != NGX_AGAIN && pr->postponed->request == r) {
                pr->postponed = pr->postponed->next;
            }

            if (r->fast_subrequest) {
                ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http fast subrequest: \"%V?%V\" done",
                           &r->uri, &r->args);
                return;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http wake parent request: \"%V?%V\"",
                           &pr->uri, &pr->args);

            pr->write_event_handler(pr);

#if 0
            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http request: \"%V?%V\" still has postponed",
                           &pr->uri, &pr->args);

            if (pr->done || pr->postponed->out) {
                ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                               "http wake parent request: \"%V?%V\"",
                               &pr->uri, &pr->args);

                pr->write_event_handler(pr);
            }
#endif

        }

        return;
    }

    if (rc == NGX_AGAIN) {
        return;
    }

    if (r->connection->buffered) {
        (void) ngx_http_set_write_handler(r);
        return;
    }

    if (ngx_http_post_action(r) == NGX_OK) {
        return;
    }

    if (r->connection->read->timer_set) {
        ngx_del_timer(r->connection->read);
    }

    if (r->connection->write->timer_set) {
        r->connection->write->delayed = 0;
        ngx_del_timer(r->connection->write);
    }

    if (r->connection->destroyed) {
        return;
    }

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    if (!ngx_terminate
         && !ngx_exiting
         && r->keepalive != 0
         && clcf->keepalive_timeout > 0)
    {
        ngx_http_set_keepalive(r);
        return;

    } else if (r->lingering_close && clcf->lingering_timeout > 0) {
        ngx_http_set_lingering_close(r);
        return;
    }

    ngx_http_close_request(r, 0);
}


static ngx_int_t
ngx_http_set_write_handler(ngx_http_request_t *r)
{
    ngx_event_t               *wev;
    ngx_http_core_loc_conf_t  *clcf;

    r->http_state = NGX_HTTP_WRITING_REQUEST_STATE;

    r->write_event_handler = ngx_http_writer;

    wev = r->connection->write;

    if (wev->ready && wev->delayed) {
        return NGX_OK;
    }

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
    if (!wev->delayed) {
        ngx_add_timer(wev, clcf->send_timeout);
    }

    if (ngx_handle_write_event(wev, clcf->send_lowat) == NGX_ERROR) {
        ngx_http_close_request(r, 0);
        return NGX_ERROR;
    }

    return NGX_OK;
}


static void
ngx_http_writer(ngx_http_request_t *r)
{
    int                        rc;
    ngx_event_t               *wev;
    ngx_connection_t          *c;
    ngx_http_core_loc_conf_t  *clcf;

    c = r->connection;
    wev = c->write;

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                   "http writer handler: \"%V?%V\"", &r->uri, &r->args);

    if (wev->timedout) {
        if (!wev->delayed) {
            ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
                          "client timed out");
            c->timedout = 1;

            ngx_http_finalize_request(r, NGX_HTTP_REQUEST_TIME_OUT);
            return;
        }

        wev->timedout = 0;
        wev->delayed = 0;

        if (!wev->ready) {
            clcf = ngx_http_get_module_loc_conf(r->main, ngx_http_core_module);
            ngx_add_timer(wev, clcf->send_timeout);

            if (ngx_handle_write_event(wev, clcf->send_lowat) == NGX_ERROR) {
                ngx_http_close_request(r, 0);
            }

            return;
        }

    } else {
        if (wev->delayed) {
            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                           "http writer delayed");

            clcf = ngx_http_get_module_loc_conf(r->main, ngx_http_core_module);

            if (ngx_handle_write_event(wev, clcf->send_lowat) == NGX_ERROR) {
                ngx_http_close_request(r, 0);
            }

            return;
        }
    }

    rc = ngx_http_output_filter(r, NULL);

    if (c->destroyed) {
        return;
    }

    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http writer output filter: %d, \"%V?%V\"",
                   rc, &r->uri, &r->args);

    if (rc == NGX_AGAIN) {
        clcf = ngx_http_get_module_loc_conf(r->main, ngx_http_core_module);
        if (!wev->ready && !wev->delayed) {
            ngx_add_timer(wev, clcf->send_timeout);
        }

        if (ngx_handle_write_event(wev, clcf->send_lowat) == NGX_ERROR) {
            ngx_http_close_request(r, 0);
        }

        if (r == r->main) {
            return;
        }

        rc = NGX_OK;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                   "http writer done: \"%V?%V\"", &r->uri, &r->args);

    ngx_http_finalize_request(r, rc);
}


static void
ngx_http_block_read(ngx_http_request_t *r)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http read blocked");

    /* aio does not call this handler */

    if ((ngx_event_flags & NGX_USE_LEVEL_EVENT)
        && r->connection->read->active)
    {
        if (ngx_del_event(r->connection->read, NGX_READ_EVENT, 0)
            == NGX_ERROR)
        {
            ngx_http_close_request(r, 0);
        }
    }
}


ngx_int_t
ngx_http_discard_body(ngx_http_request_t *r)
{
    ssize_t       size;
    ngx_event_t  *rev;

    if (r != r->main) {
        return NGX_OK;
    }

    rev = r->connection->read;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0, "http set discard body");

    if (rev->timer_set) {
        ngx_del_timer(rev);
    }

    if (r->headers_in.content_length_n <= 0) {
        return NGX_OK;
    }

    r->discard_body = 1;

    size = r->header_in->last - r->header_in->pos;

    if (size) {
        if (r->headers_in.content_length_n > size) {
            r->headers_in.content_length_n -= size;

        } else {
            r->header_in->pos += r->headers_in.content_length_n;
            r->headers_in.content_length_n = 0;
            return NGX_OK;
        }
    }

    r->read_event_handler = ngx_http_read_discarded_body_handler;

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    return ngx_http_read_discarded_body(r);
}


static void
ngx_http_read_discarded_body_handler(ngx_http_request_t *r)
{
    ngx_int_t  rc;

    rc = ngx_http_read_discarded_body(r);

    if (rc == NGX_AGAIN) {
        if (ngx_handle_read_event(r->connection->read, 0) == NGX_ERROR) {
            ngx_http_close_request(r, rc);
            return;
        }
    }

    if (rc != NGX_OK) {
        ngx_http_close_request(r, rc);
    }
}


static ngx_int_t
ngx_http_read_discarded_body(ngx_http_request_t *r)
{
    ssize_t  size, n;
    u_char   buffer[NGX_HTTP_DISCARD_BUFFER_SIZE];

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http read discarded body");

    if (r->headers_in.content_length_n == 0) {
        return NGX_OK;
    }


    size = r->headers_in.content_length_n;

    if (size > NGX_HTTP_DISCARD_BUFFER_SIZE) {
        size = NGX_HTTP_DISCARD_BUFFER_SIZE;
    }

    n = r->connection->recv(r->connection, buffer, size);

    if (n == NGX_ERROR) {

        r->connection->error = 1;

        /*
         * if a client request body is discarded then we already set
         * some HTTP response code for client and we can ignore the error
         */

        return NGX_OK;
    }

    if (n == NGX_AGAIN) {
        return NGX_AGAIN;
    }

    r->headers_in.content_length_n -= n;

    return NGX_OK;
}


static void
ngx_http_set_keepalive(ngx_http_request_t *r)
{
    int                        tcp_nodelay;
    ngx_int_t                  i;
    ngx_buf_t                 *b, *f;
    ngx_event_t               *rev, *wev;
    ngx_connection_t          *c;
    ngx_http_connection_t     *hc;
    ngx_http_core_srv_conf_t  *cscf;
    ngx_http_core_loc_conf_t  *clcf;

    c = r->connection;
    rev = c->read;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "set http keepalive handler");

    c->log->action = "closing request";

    hc = r->http_connection;
    b = r->header_in;

    if (b->pos < b->last) {

        /* the pipelined request */

        if (b != c->buffer) {

            /*
             * If the large header buffers were allocated while the previous
             * request processing then we do not use c->buffer for
             * the pipelined request (see ngx_http_init_request()).
             *
             * Now we would move the large header buffers to the free list.
             */

            cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);

            if (hc->free == NULL) {
                hc->free = ngx_palloc(c->pool,
                  cscf->large_client_header_buffers.num * sizeof(ngx_buf_t *));

                if (hc->free == NULL) {
                    ngx_http_close_request(r, 0);
                    return;
                }
            }

            for (i = 0; i < hc->nbusy - 1; i++) {
                f = hc->busy[i];
                hc->free[hc->nfree++] = f;
                f->pos = f->start;
                f->last = f->start;
            }

            hc->busy[0] = b;
            hc->nbusy = 1;
        }
    }

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    ngx_http_request_done(r, 0);

    c->data = hc;

    ngx_add_timer(rev, clcf->keepalive_timeout);

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
        ngx_http_close_connection(c);
        return;
    }

    wev = c->write;
    wev->handler = ngx_http_empty_handler;

    if (b->pos < b->last) {

        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "pipelined request");

#if (NGX_STAT_STUB)
        ngx_atomic_fetch_add(ngx_stat_reading, 1);
#endif

        hc->pipeline = 1;
        c->log->action = "reading client pipelined request line";

        ngx_http_init_request(rev);
        return;
    }

    hc->pipeline = 0;

    /*
     * To keep a memory footprint as small as possible for an idle
     * keepalive connection we try to free the ngx_http_request_t and
     * c->buffer's memory if they were allocated outside the c->pool.
     * The large header buffers are always allocated outside the c->pool and
     * are freed too.
     */

    if (ngx_pfree(c->pool, r) == NGX_OK) {
        hc->request = NULL;
    }

    b = c->buffer;

    if (ngx_pfree(c->pool, b->start) == NGX_OK) {

        /*
         * the special note for ngx_http_keepalive_handler() that
         * c->buffer's memory was freed
         */

        b->pos = NULL;

    } else {
        b->pos = b->start;
        b->last = b->start;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "hc free: %p %d",
                   hc->free, hc->nfree);

    if (hc->free) {
        for (i = 0; i < hc->nfree; i++) {
            ngx_pfree(c->pool, hc->free[i]);
            hc->free[i] = NULL;
        }

        hc->nfree = 0;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "hc busy: %p %d",
                   hc->busy, hc->nbusy);

    if (hc->busy) {
        for (i = 0; i < hc->nbusy; i++) {
            ngx_pfree(c->pool, hc->busy[i]);
            hc->busy[i] = NULL;
        }

        hc->nbusy = 0;
    }

    rev->handler = ngx_http_keepalive_handler;

    if (wev->active && (ngx_event_flags & NGX_USE_LEVEL_EVENT)) {
        if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
            ngx_http_close_connection(c);
            return;
        }
    }

    c->log->action = "keepalive";

    if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
        if (ngx_tcp_push(c->fd) == -1) {
            ngx_connection_error(c, ngx_socket_errno, ngx_tcp_push_n " failed");
            ngx_http_close_connection(c);
            return;
        }

        c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
        tcp_nodelay = ngx_tcp_nodelay_and_tcp_nopush ? 1 : 0;

    } else {
        tcp_nodelay = 1;
    }

    if (tcp_nodelay
        && clcf->tcp_nodelay
        && c->tcp_nodelay == NGX_TCP_NODELAY_UNSET)
    {
        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "tcp_nodelay");

        if (setsockopt(c->fd, IPPROTO_TCP, TCP_NODELAY,
                           (const void *) &tcp_nodelay, sizeof(int)) == -1)
        {
            ngx_connection_error(c, ngx_socket_errno,
                                 "setsockopt(TCP_NODELAY) failed");
            ngx_http_close_connection(c);
            return;
        }

        c->tcp_nodelay = NGX_TCP_NODELAY_SET;
    }

#if 0
    /* if ngx_http_request_t was freed then we need some other place */
    r->http_state = NGX_HTTP_KEEPALIVE_STATE;
#endif

    if (rev->ready) {
        ngx_http_keepalive_handler(rev);
    }
}


static void
ngx_http_keepalive_handler(ngx_event_t *rev)
{
    size_t             size;
    ssize_t            n;
    ngx_buf_t         *b;
    ngx_connection_t  *c;

    c = rev->data;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http keepalive handler");

    if (rev->timedout) {
        ngx_http_close_connection(c);
        return;
    }

#if (NGX_HAVE_KQUEUE)

    if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
        if (rev->pending_eof) {
            c->log->handler = NULL;
            ngx_log_error(NGX_LOG_INFO, c->log, rev->kq_errno,
                          "kevent() reported that client %V closed "
                          "keepalive connection", &c->addr_text);
#if (NGX_HTTP_SSL)
            if (c->ssl) {
                c->ssl->no_send_shutdown = 1;
            }
#endif
            ngx_http_close_connection(c);
            return;
        }
    }

#endif

    b = c->buffer;
    size = b->end - b->start;

    if (b->pos == NULL) {

        /*
         * The c->buffer's memory was freed by ngx_http_set_keepalive().
         * However, the c->buffer->start and c->buffer->end were not changed
         * to keep the buffer size.
         */

        b->pos = ngx_palloc(c->pool, size);
        if (b->pos == NULL) {
            ngx_http_close_connection(c);
            return;
        }

        b->start = b->pos;
        b->last = b->pos;
        b->end = b->pos + size;
    }

    /*
     * MSIE closes a keepalive connection with RST flag
     * so we ignore ECONNRESET here.
     */

    c->log_error = NGX_ERROR_IGNORE_ECONNRESET;
    ngx_set_socket_errno(0);

    n = c->recv(c, b->last, size);
    c->log_error = NGX_ERROR_INFO;

    if (n == NGX_AGAIN) {
        if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
            ngx_http_close_connection(c);
        }

        return;
    }

    if (n == NGX_ERROR) {
        ngx_http_close_connection(c);
        return;
    }

    c->log->handler = NULL;

    if (n == 0) {
        ngx_log_error(NGX_LOG_INFO, c->log, ngx_socket_errno,
                      "client %V closed keepalive connection", &c->addr_text);
        ngx_http_close_connection(c);
        return;
    }

    b->last += n;

#if (NGX_STAT_STUB)
    ngx_atomic_fetch_add(ngx_stat_reading, 1);
#endif

    c->log->handler = ngx_http_log_error;
    c->log->action = "reading client request line";

    ngx_http_init_request(rev);
}


static void
ngx_http_set_lingering_close(ngx_http_request_t *r)
{
    ngx_event_t               *rev, *wev;
    ngx_connection_t          *c;
    ngx_http_core_loc_conf_t  *clcf;

    c = r->connection;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    rev = c->read;
    rev->handler = ngx_http_lingering_close_handler;

    r->lingering_time = ngx_time() + (time_t) (clcf->lingering_time / 1000);
    ngx_add_timer(rev, clcf->lingering_timeout);

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
        ngx_http_close_request(r, 0);
        return;
    }

    wev = c->write;
    wev->handler = ngx_http_empty_handler;

    if (wev->active && (ngx_event_flags & NGX_USE_LEVEL_EVENT)) {
        if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
            ngx_http_close_request(r, 0);
            return;
        }
    }

    if (ngx_shutdown_socket(c->fd, NGX_WRITE_SHUTDOWN) == -1) {
        ngx_connection_error(c, ngx_socket_errno,
                             ngx_shutdown_socket_n " failed");
        ngx_http_close_request(r, 0);
        return;
    }

    if (rev->ready) {
        ngx_http_lingering_close_handler(rev);
    }
}


static void
ngx_http_lingering_close_handler(ngx_event_t *rev)
{
    ssize_t                    n;
    ngx_msec_t                 timer;
    ngx_connection_t          *c;
    ngx_http_request_t        *r;
    ngx_http_core_loc_conf_t  *clcf;
    u_char                     buffer[NGX_HTTP_LINGERING_BUFFER_SIZE];

    c = rev->data;
    r = c->data;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http lingering close handler");

    if (rev->timedout) {
        c->timedout = 1;
        ngx_http_close_request(r, 0);
        return;
    }

    timer = r->lingering_time - ngx_time();
    if (timer <= 0) {
        ngx_http_close_request(r, 0);
        return;
    }

    do {
        n = c->recv(c, buffer, NGX_HTTP_LINGERING_BUFFER_SIZE);

        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "lingering read: %d", n);

        if (n == NGX_ERROR || n == 0) {
            ngx_http_close_request(r, 0);
            return;
        }

    } while (rev->ready);

    if (ngx_handle_read_event(rev, 0) == NGX_ERROR) {
        ngx_http_close_request(r, 0);
        return;
    }

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    timer *= 1000;

    if (timer > clcf->lingering_timeout) {
        timer = clcf->lingering_timeout;
    }

    ngx_add_timer(rev, timer);
}


void
ngx_http_empty_handler(ngx_event_t *wev)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, wev->log, 0, "http empty handler");

    return;
}


void
ngx_http_request_empty_handler(ngx_http_request_t *r)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http request empty handler");

    return;
}


ngx_int_t
ngx_http_send_special(ngx_http_request_t *r, ngx_uint_t flags)
{
    ngx_buf_t    *b;
    ngx_chain_t   out;

    b = ngx_calloc_buf(r->pool);
    if (b == NULL) {
        return NGX_ERROR;
    }

    if (flags & NGX_HTTP_LAST) {
        b->last_buf = 1;
    }

    if (flags & NGX_HTTP_FLUSH) {
        b->flush = 1;
    }

    out.buf = b;
    out.next = NULL;

    return ngx_http_output_filter(r, &out);
}


static ngx_int_t
ngx_http_post_action(ngx_http_request_t *r)
{
    ngx_http_core_loc_conf_t  *clcf;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    if (clcf->post_action.data == NULL) {
        return NGX_DECLINED;
    }

    r->http_version = NGX_HTTP_VERSION_9;
    r->header_only = 1;

    ngx_http_internal_redirect(r, &clcf->post_action, NULL);

    return NGX_OK;
}


static void
ngx_http_close_request(ngx_http_request_t *r, ngx_int_t error)
{
    ngx_connection_t    *c;
    ngx_http_cleanup_t  *cln;

    c = r->connection;
    r = r->main;

    for (cln = r->cleanup; cln; cln = cln->next) {
        if (cln->handler) {
            cln->handler(cln->data);
        }
    }

    ngx_http_request_done(r, error);
    ngx_http_close_connection(c);
}


static void
ngx_http_request_done(ngx_http_request_t *r, ngx_int_t error)
{
    ngx_log_t                  *log;
    ngx_uint_t                  i, n;
    struct linger               linger;
    ngx_http_log_ctx_t         *ctx;
    ngx_http_handler_pt        *log_handler;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_core_main_conf_t  *cmcf;

    log = r->connection->log;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "http close request");

    if (r->pool == NULL) {
        ngx_log_error(NGX_LOG_ALERT, log, 0, "http request already closed");
        return;
    }

#if (NGX_STAT_STUB)

    if (r->stat_reading) {
        ngx_atomic_fetch_add(ngx_stat_reading, -1);
    }

    if (r->stat_writing) {
        ngx_atomic_fetch_add(ngx_stat_writing, -1);
    }

#endif

    if (error && r->headers_out.status == 0) {
        r->headers_out.status = error;
    }

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    log_handler = cmcf->phases[NGX_HTTP_LOG_PHASE].handlers.elts;
    n = cmcf->phases[NGX_HTTP_LOG_PHASE].handlers.nelts;
    for (i = 0; i < n; i++) {
        log_handler[i](r);
    }

    if (r->connection->timedout) {
        clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

        if (clcf->reset_timedout_connection) {
            linger.l_onoff = 1;
            linger.l_linger = 0;

            if (setsockopt(r->connection->fd, SOL_SOCKET, SO_LINGER,
                           (const void *) &linger, sizeof(struct linger)) == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno,
                              "setsockopt(SO_LINGER) failed");
            }
        }
    }

    /* the various request strings were allocated from r->pool */
    ctx = log->data;
    ctx->request = NULL;

    r->request_line.len = 0;

    r->connection->destroyed = 1;

    ngx_destroy_pool(r->pool);
}


static void
ngx_http_close_connection(ngx_connection_t *c)
{
    ngx_pool_t  *pool;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "close http connection: %d", c->fd);

#if (NGX_HTTP_SSL)

    if (c->ssl) {
        if (ngx_ssl_shutdown(c) == NGX_AGAIN) {
            c->ssl->handler = ngx_http_close_connection;
            return;
        }
    }

#endif

#if (NGX_STAT_STUB)
    ngx_atomic_fetch_add(ngx_stat_active, -1);
#endif

    c->destroyed = 1;

    pool = c->pool;

    ngx_close_connection(c);

    ngx_destroy_pool(pool);
}


static u_char *
ngx_http_log_error(ngx_log_t *log, u_char *buf, size_t len)
{
    u_char              *p;
    ngx_http_request_t  *r;
    ngx_http_log_ctx_t  *ctx;

    if (log->action) {
        p = ngx_snprintf(buf, len, " while %s", log->action);
        len -= p - buf;
        buf = p;
    }

    ctx = log->data;

    p = ngx_snprintf(buf, len, ", client: %V", ctx->client);
    len -= p - buf;

    r = ctx->request;

    if (r) {
        return r->log_handler(r, p, len);
    }

    return p;
}


static u_char *
ngx_http_log_error_handler(ngx_http_request_t *r, u_char *buf, size_t len)
{
    u_char  *p;

    if (r->server_name.data) {
        p = ngx_snprintf(buf, len, ", server: %V", &r->server_name);
        len -= p - buf;
        buf = p;
    }

    if (r->unparsed_uri.data) {
        p = ngx_snprintf(buf, len, ", URL: \"%V\"", &r->unparsed_uri);
        len -= p - buf;
        buf = p;

    } else {
        if (r->request_line.data == NULL && r->request_start) {
            for (p = r->request_start; p < r->header_in->last; p++) {
                if (*p == CR || *p == LF) {
                    break;
                }
            }

            r->request_line.len = p - r->request_start;
            r->request_line.data = r->request_start;
        }

        if (r->request_line.len) {
            p = ngx_snprintf(buf, len, ", request: \"%V\"", &r->request_line);
            len -= p - buf;
            buf = p;
        }
    }

    return ngx_http_log_error_info(r, buf, len);
}


u_char *
ngx_http_log_error_info(ngx_http_request_t *r, u_char *buf, size_t len)
{
    u_char  *p;

    if (r->headers_in.host) {
        p = ngx_snprintf(buf, len, ", host: \"%V\"",
                         &r->headers_in.host->value);
        len -= p - buf;
        buf = p;
    }

    if (r->headers_in.referer) {
        p = ngx_snprintf(buf, len, ", referrer: \"%V\"",
                         &r->headers_in.referer->value);
        buf = p;
    }

    return buf;
}