MINOR: proto_reverse_connect: support source address setting

Support backend configuration for explicit source address on
pre-connect. These settings can be specified via "source" backend
keyword or directly on the server line.

Previously, all source parameters triggered a BUG_ON() when binding a
reverse connect listener. This was done because some settings are
incompatible with reverse connect context : this is the case for all
source settings which do not specify a fixed address but rather rely on
a frontend connection. Indeed, in case of preconnect, connection is
initiated on its own without the existence of a previous frontend
connection.

This patch allows to use a source parameter with a fixed address. All
other settings (usesrc client/clientip/hdr_ip) are rejected on listener
binding. On connection init, alloc_bind_address() is used to set the
optional source address.

diff --git a/src/proto_reverse_connect.c b/src/proto_reverse_connect.c
index 61cf448065556f91b8a7e99b1816ec90eaf22a81..ef9e40f469acc76b9cbe53d630c52c74194ac375 100644 (file)
--- a/src/proto_reverse_connect.c
+++ b/src/proto_reverse_connect.c
@@ -50,14 +50,15 @@ struct protocol proto_reverse_connect = {
 static struct connection *new_reverse_conn(struct listener *l, struct server *srv)
 {
        struct connection *conn = conn_new(srv);
+       struct sockaddr_storage *bind_addr = NULL;
        if (!conn)
                goto err;
 
        conn_set_reverse(conn, &l->obj_type);
 
-       /* These options is incompatible with a reverse connection. */
-       BUG_ON(srv->conn_src.opts & CO_SRC_BIND);
-       BUG_ON(srv->proxy->conn_src.opts & CO_SRC_BIND);
+       if (alloc_bind_address(&bind_addr, srv, srv->proxy, NULL) != SRV_STATUS_OK)
+               goto err;
+       conn->src = bind_addr;
 
        sockaddr_alloc(&conn->dst, 0, 0);
        if (!conn->dst)
@@ -247,6 +248,16 @@ int rev_bind_listener(struct listener *listener, char *errmsg, int errlen)
                snprintf(errmsg, errlen, "Cannot reverse connect with server '%s/%s' unless HTTP/2 is activated on it with either proto or alpn keyword.", name, ist0(sv_name));
                goto err;
        }
+
+       /* Prevent dynamic source address settings. */
+       if (((srv->conn_src.opts & CO_SRC_TPROXY_MASK) &&
+            (srv->conn_src.opts & CO_SRC_TPROXY_MASK) != CO_SRC_TPROXY_ADDR) ||
+           ((srv->proxy->conn_src.opts & CO_SRC_TPROXY_MASK) &&
+            (srv->proxy->conn_src.opts & CO_SRC_TPROXY_MASK) != CO_SRC_TPROXY_ADDR)) {
+               snprintf(errmsg, errlen, "Cannot reverse connect with server '%s/%s' which uses dynamic source address setting.", name, ist0(sv_name));
+               goto err;
+       }
+
        ha_free(&name);
 
        listener->rx.reverse_connect.srv = srv;