res_rtp_asterisk: Allow remote SSRC to change on an RTP instance.

When SDP renegotiation occurs it is possible for an RTP
instance to be reused for a new stream, resulting in the remote
SSRC changing if it is part of a bundle group. This change
allows this and updates its mapping in the current bundle
group.

ASTERISK-27231

Change-Id: I6e3703974f236bc024c5dbe9bd43adae0c6fb490

1 files changed, 26 insertions, 1 deletions

diff --git a/res/res_rtp_asterisk.c b/res/res_rtp_asterisk.c
index 0f4f6abda..ab8038422 100644
--- a/res/res_rtp_asterisk.c
+++ b/res/res_rtp_asterisk.c
@@ -6173,10 +6173,35 @@ static void ast_rtp_set_remote_ssrc(struct ast_rtp_instance *instance, unsigned
 {
 	struct ast_rtp *rtp = ast_rtp_instance_get_data(instance);
 
-	if (rtp->themssrc) {
+	if (rtp->themssrc == ssrc) {
 		return;
 	}
 
+	/* If this is bundled we need to update the SSRC mapping */
+	if (rtp->bundled) {
+		struct ast_rtp *bundled_rtp;
+		int index;
+
+		ao2_unlock(instance);
+
+		/* The child lock can't be held while accessing the parent */
+		ao2_lock(rtp->bundled);
+		bundled_rtp = ast_rtp_instance_get_data(rtp->bundled);
+
+		for (index = 0; index < AST_VECTOR_SIZE(&bundled_rtp->ssrc_mapping); ++index) {
+			struct rtp_ssrc_mapping *mapping = AST_VECTOR_GET_ADDR(&bundled_rtp->ssrc_mapping, index);
+
+			if (mapping->ssrc == rtp->themssrc) {
+				mapping->ssrc = ssrc;
+				break;
+			}
+		}
+
+		ao2_unlock(rtp->bundled);
+
+		ao2_lock(instance);
+	}
+
 	rtp->themssrc = ssrc;
 }