Stream: udp streams.

Previously, only one client packet could be processed in a udp stream session
even though multiple response packets were supported.  Now multiple packets
coming from the same client address and port are delivered to the same stream
session.

If it's required to maintain a single stream of data, nginx should be
configured in a way that all packets from a client are delivered to the same
worker.  On Linux and DragonFly BSD the "reuseport" parameter should be
specified for this.  Other systems do not currently provide appropriate
mechanisms.  For these systems a single stream of udp packets is only
guaranteed in single-worker configurations.

The proxy_response directive now specifies how many packets are expected in
response to a single client packet.

3 files changed, 10 insertions, 0 deletions

diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
index 878c6be19..dc6067922 100644
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -72,6 +72,10 @@ ngx_create_listening(ngx_conf_t *cf, struct sockaddr *sockaddr,
 
     ngx_memcpy(ls->addr_text.data, text, len);
 
+#if !(NGX_WIN32)
+    ngx_rbtree_init(&ls->rbtree, &ls->sentinel, ngx_udp_rbtree_insert_value);
+#endif
+
     ls->fd = (ngx_socket_t) -1;
     ls->type = SOCK_STREAM;
 
diff --git a/src/core/ngx_connection.h b/src/core/ngx_connection.h
index e4dfe5879..ef0755800 100644
--- a/src/core/ngx_connection.h
+++ b/src/core/ngx_connection.h
@@ -51,6 +51,9 @@ struct ngx_listening_s {
     ngx_listening_t    *previous;
     ngx_connection_t   *connection;
 
+    ngx_rbtree_t        rbtree;
+    ngx_rbtree_node_t   sentinel;
+
     ngx_uint_t          worker;
 
     unsigned            open:1;
@@ -151,6 +154,8 @@ struct ngx_connection_s {
     ngx_ssl_connection_t  *ssl;
 #endif
 
+    ngx_udp_connection_t  *udp;
+
     struct sockaddr    *local_sockaddr;
     socklen_t           local_socklen;
 
diff --git a/src/core/ngx_core.h b/src/core/ngx_core.h
index 2069373ba..93ca9174d 100644
--- a/src/core/ngx_core.h
+++ b/src/core/ngx_core.h
@@ -27,6 +27,7 @@ typedef struct ngx_connection_s      ngx_connection_t;
 typedef struct ngx_thread_task_s     ngx_thread_task_t;
 typedef struct ngx_ssl_s             ngx_ssl_t;
 typedef struct ngx_ssl_connection_s  ngx_ssl_connection_t;
+typedef struct ngx_udp_connection_s  ngx_udp_connection_t;
 
 typedef void (*ngx_event_handler_pt)(ngx_event_t *ev);
 typedef void (*ngx_connection_handler_pt)(ngx_connection_t *c);