# HG changeset patch
# User Vladimir Homutov <vl@nginx.com>
# Date 1632295200 -10800
# Node ID bfad703459b4e2416548ac66f548e96c2197d9cc
# Parent  97cf8284fd19b30169231e43831e7787baba72f2
Stream: added half-close support.

The "proxy_half_close" directive enables handling of TCP half close.  If
enabled, connection to proxied server is kept open until both read ends get
EOF.  Write end shutdown is properly transmitted via proxy.

diff --git a/src/stream/ngx_stream_proxy_module.c b/src/stream/ngx_stream_proxy_module.c
--- a/src/stream/ngx_stream_proxy_module.c
+++ b/src/stream/ngx_stream_proxy_module.c
@@ -31,6 +31,7 @@ typedef struct {
     ngx_uint_t                       next_upstream_tries;
     ngx_flag_t                       next_upstream;
     ngx_flag_t                       proxy_protocol;
+    ngx_flag_t                       half_close;
     ngx_stream_upstream_local_t     *local;
     ngx_flag_t                       socket_keepalive;
 
@@ -245,6 +246,13 @@ static ngx_command_t  ngx_stream_proxy_c
       offsetof(ngx_stream_proxy_srv_conf_t, proxy_protocol),
       NULL },
 
+    { ngx_string("proxy_half_close"),
+      NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_STREAM_SRV_CONF_OFFSET,
+      offsetof(ngx_stream_proxy_srv_conf_t, half_close),
+      NULL },
+
 #if (NGX_STREAM_SSL)
 
     { ngx_string("proxy_ssl"),
@@ -1755,6 +1763,24 @@ ngx_stream_proxy_process(ngx_stream_sess
     }
 
     if (dst) {
+
+        if (dst->type == SOCK_STREAM && pscf->half_close
+            && src->read->eof && !u->half_closed && !dst->buffered)
+        {
+            if (ngx_shutdown_socket(dst->fd, NGX_WRITE_SHUTDOWN) == -1) {
+                ngx_connection_error(c, ngx_socket_errno,
+                                     ngx_shutdown_socket_n " failed");
+
+                ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
+                return;
+            }
+
+            u->half_closed = 1;
+            ngx_log_debug1(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
+                           "stream proxy %s socket shutdown",
+                           from_upstream ? "client" : "upstream");
+        }
+
         if (ngx_handle_write_event(dst->write, 0) != NGX_OK) {
             ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
             return;
@@ -1833,6 +1859,13 @@ ngx_stream_proxy_test_finalize(ngx_strea
         return NGX_DECLINED;
     }
 
+    if (pscf->half_close) {
+        /* avoid closing live connections until both read ends get EOF */
+        if (!(c->read->eof && pc->read->eof && !c->buffered && !pc->buffered)) {
+             return NGX_DECLINED;
+        }
+    }
+
     handler = c->log->handler;
     c->log->handler = NULL;
 
@@ -2052,6 +2085,7 @@ ngx_stream_proxy_create_srv_conf(ngx_con
     conf->proxy_protocol = NGX_CONF_UNSET;
     conf->local = NGX_CONF_UNSET_PTR;
     conf->socket_keepalive = NGX_CONF_UNSET;
+    conf->half_close = NGX_CONF_UNSET;
 
 #if (NGX_STREAM_SSL)
     conf->ssl_enable = NGX_CONF_UNSET;
@@ -2110,6 +2144,8 @@ ngx_stream_proxy_merge_srv_conf(ngx_conf
     ngx_conf_merge_value(conf->socket_keepalive,
                               prev->socket_keepalive, 0);
 
+    ngx_conf_merge_value(conf->half_close, prev->half_close, 0);
+
 #if (NGX_STREAM_SSL)
 
     ngx_conf_merge_value(conf->ssl_enable, prev->ssl_enable, 0);
diff --git a/src/stream/ngx_stream_upstream.h b/src/stream/ngx_stream_upstream.h
--- a/src/stream/ngx_stream_upstream.h
+++ b/src/stream/ngx_stream_upstream.h
@@ -142,6 +142,7 @@ typedef struct {
     ngx_stream_upstream_state_t       *state;
     unsigned                           connected:1;
     unsigned                           proxy_protocol:1;
+    unsigned                           half_closed:1;
 } ngx_stream_upstream_t;