libosmo-mgcp: Connection Identifiers are allocated by MGW, not CA
The MGCP connection identifier is allocated by the MGW while processing
the CRCX, see RFC3435 2.1.3.2:. Including/Accepting a connection
identifier in CRCX is "forbidden" as per RFC3435 Section 3.2.2.
So the MGW side must *reject* a CRCX message with 'I' parameter, and
allocate a connection identifier which is subsequently returned in the
response.
Closes: OS#2648
Change-Id: Iab6a6038e7610c62f34e642cd49c93d11151252c
diff --git a/src/libosmo-mgcp/mgcp_protocol.c b/src/libosmo-mgcp/mgcp_protocol.c
index 672a8d4..feca8da 100644
--- a/src/libosmo-mgcp/mgcp_protocol.c
+++ b/src/libosmo-mgcp/mgcp_protocol.c
@@ -447,7 +447,7 @@
char *line;
int have_sdp = 0, osmux_cid = -1;
struct mgcp_conn_rtp *conn = NULL;
- const char *conn_id = NULL;
+ struct mgcp_conn *_conn = NULL;
char conn_name[512];
LOGP(DLMGCP, LOGL_NOTICE, "CRCX: creating new connection ...\n");
@@ -468,7 +468,10 @@
callid = (const char *)line + 3;
break;
case 'I':
- conn_id = (const char *)line + 3;
+ /* It is illegal to send a connection identifier
+ * together with a CRCX, the MGW will assign the
+ * connection identifier by itself on CRCX */
+ return create_err_response(NULL, 523, "CRCX", p->trans);
break;
case 'M':
mode = (const char *)line + 3;
@@ -510,13 +513,6 @@
return create_err_response(endp, 400, "CRCX", p->trans);
}
- if (!conn_id) {
- LOGP(DLMGCP, LOGL_ERROR,
- "CRCX: endpoint:%x insufficient parameters, missing connection id\n",
- ENDPOINT_NUMBER(endp));
- return create_err_response(endp, 400, "CRCX", p->trans);
- }
-
/* Check if we are able to accept the creation of another connection */
if (llist_count(&endp->conns) >= endp->type->max_conns) {
LOGP(DLMGCP, LOGL_ERROR,
@@ -560,32 +556,17 @@
set_local_cx_options(endp->tcfg->endpoints, &endp->local_options,
local_options);
- /* Only accept another connection when the connection ID is different. */
- if (mgcp_conn_get_rtp(endp, conn_id)) {
- LOGP(DLMGCP, LOGL_ERROR,
- "CRCX: endpoint:%x there is already a connection with id %u present!\n",
- conn_id, ENDPOINT_NUMBER(endp));
- if (tcfg->force_realloc) {
- /* Ignore the existing connection by just freeing it */
- mgcp_conn_free(endp, conn_id);
- } else {
- /* There is already a connection with that ID present,
- * leave everything as it is and return with an error. */
- return create_err_response(endp, 400, "CRCX", p->trans);
- }
- }
-
- snprintf(conn_name, sizeof(conn_name), "%s-%s", callid, conn_id);
- mgcp_conn_alloc(NULL, endp, conn_id, MGCP_CONN_TYPE_RTP,
- conn_name);
- conn = mgcp_conn_get_rtp(endp, conn_id);
- if (!conn) {
+ snprintf(conn_name, sizeof(conn_name), "%s", callid);
+ _conn = mgcp_conn_alloc(NULL, endp, MGCP_CONN_TYPE_RTP, conn_name);
+ if (!_conn) {
LOGP(DLMGCP, LOGL_ERROR,
"CRCX: endpoint:%x unable to allocate RTP connection\n",
ENDPOINT_NUMBER(endp));
goto error2;
}
+ conn = mgcp_conn_get_rtp(endp, _conn->id);
+ OSMO_ASSERT(conn);
if (mgcp_parse_conn_mode(mode, endp, conn->conn) != 0) {
error_code = 517;