# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1390909246 -14400
# Node ID 462ae7eedc681205070d53bb3d46a9bc4eed9744
# Parent  560de9681661c63b03559616c693a5a2e08b5fca
Fixed TCP_DEFER_ACCEPT handling (ticket #353).

Backed out 05a56ebb084a, as it turns out that kernel can return connections
without any delay if syncookies are used.  This basically means we can't
assume anything about connections returned with deferred accept set.

To solve original problem the 05a56ebb084a tried to solve, i.e. to don't
wait longer than needed if a connection was accepted after deferred accept
timeout, this patch changes a timeout set with setsockopt(TCP_DEFER_ACCEPT)
to 1 second, unconditionally.  This is believed to be enough for speed
improvements, and doesn't imply major changes to timeouts used.

Note that before 2.6.32 connections were dropped after a timeout.  Though
it is believed that 1s is still appropriate for kernels before 2.6.32,
as previously tcp_synack_retries controlled the actual timeout and 1s results
in more than 1 minute actual timeout by default.

diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -647,7 +647,13 @@ ngx_configure_listening_sockets(ngx_cycl
         if (ls[i].add_deferred || ls[i].delete_deferred) {
 
             if (ls[i].add_deferred) {
-                timeout = (int) (ls[i].post_accept_timeout / 1000);
+                /*
+                 * There is no way to find out how long a connection was
+                 * in queue (and a connection may bypass deferred queue at all
+                 * if syncookies were used), hence we use 1 second timeout
+                 * here.
+                 */
+                timeout = 1;
 
             } else {
                 timeout = 0;
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -423,20 +423,6 @@ ngx_http_wait_request_handler(ngx_event_
 
     if (n == NGX_AGAIN) {
 
-#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
-        if (c->listening->deferred_accept
-#if (NGX_HTTP_SSL)
-            && c->ssl == NULL
-#endif
-            )
-        {
-            ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
-                          "client timed out in deferred accept");
-            ngx_http_close_connection(c);
-            return;
-        }
-#endif
-
         if (!rev->timer_set) {
             ngx_add_timer(rev, c->listening->post_accept_timeout);
             ngx_reusable_connection(c, 1);
@@ -635,15 +621,6 @@ ngx_http_ssl_handshake(ngx_event_t *rev)
     if (n == -1) {
         if (err == NGX_EAGAIN) {
 
-#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
-            if (c->listening->deferred_accept) {
-                ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
-                              "client timed out in deferred accept");
-                ngx_http_close_connection(c);
-                return;
-            }
-#endif
-
             if (!rev->timer_set) {
                 ngx_add_timer(rev, c->listening->post_accept_timeout);
                 ngx_reusable_connection(c, 1);