SSL: set TCP_NODELAY on SSL connections before handshake.

With OpenSSL 1.1.0+, the workaround for handshake buffer size as introduced
in a720f0b0e083 (ticket #413) no longer works, as OpenSSL no longer exposes
handshake buffers, see https://github.com/openssl/openssl/commit/2e7dc7cd688.
Moreover, it is no longer possible to adjust handshake buffers at all now.

To avoid additional RTT if handshake uses more than 4k we now set TCP_NODELAY
on SSL connections before handshake.  While this still results in sub-optimal
network utilization due to incomplete packets being sent, it seems to be
better than nothing.

1 files changed, 17 insertions, 8 deletions

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index c41f5f507..fd6b513dc 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -623,14 +623,15 @@ ngx_http_create_request(ngx_connection_t *c)
 static void
 ngx_http_ssl_handshake(ngx_event_t *rev)
 {
-    u_char                   *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER + 1];
-    size_t                    size;
-    ssize_t                   n;
-    ngx_err_t                 err;
-    ngx_int_t                 rc;
-    ngx_connection_t         *c;
-    ngx_http_connection_t    *hc;
-    ngx_http_ssl_srv_conf_t  *sscf;
+    u_char                    *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER + 1];
+    size_t                     size;
+    ssize_t                    n;
+    ngx_err_t                  err;
+    ngx_int_t                  rc;
+    ngx_connection_t          *c;
+    ngx_http_connection_t     *hc;
+    ngx_http_ssl_srv_conf_t   *sscf;
+    ngx_http_core_loc_conf_t  *clcf;
 
     c = rev->data;
     hc = c->data;
@@ -712,6 +713,14 @@ ngx_http_ssl_handshake(ngx_event_t *rev)
             ngx_log_debug1(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                            "https ssl handshake: 0x%02Xd", buf[0]);
 
+            clcf = ngx_http_get_module_loc_conf(hc->conf_ctx,
+                                                ngx_http_core_module);
+
+            if (clcf->tcp_nodelay && ngx_tcp_nodelay(c) != NGX_OK) {
+                ngx_http_close_connection(c);
+                return;
+            }
+
             sscf = ngx_http_get_module_srv_conf(hc->conf_ctx,
                                                 ngx_http_ssl_module);