Change in osmo-mgw[master]: mgw: rx CRCX: Avoid sending dummy rtp if remote address not provided

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pespin gerrit-no-reply at
Wed Jul 7 14:12:36 UTC 2021

pespin has submitted this change. ( )

Change subject: mgw: rx CRCX: Avoid sending dummy rtp if remote address not provided

mgw: rx CRCX: Avoid sending dummy rtp if remote address not provided

The following sequence of events was seen frequently in a osmo-mgw
instance running on the field with heavy traffic:
endpoint:rtpbridge/1 at mgw CRCX: creating new connection ...
mgcp_network.c:236 endpoint:rtpbridge/1 at mgw CI:1C8CCFA9 Failed to send dummy RTP packet.

Allegedly, that happens because at CRCX time the remote address may
still not be known, hence we end up trying to send a dummy rtp packet
to, for instance, host port 0, which will of course fail.
Let's avoid sending it if the address is not yet known.

Similary, same issue could be seen during MDCX, since at MDCX we don't
necessarily need to have a valid addr+port (there could be several MDCX
and only last one set it).

Finally, the keepalive timer also needs the check, since it iterates
over all connections, and it could be that some is still not fully

Related: SYS#5498
Change-Id: I8ceafda691146823b12232b4a804b4ce74acbdc8
M include/osmocom/mgcp/mgcp_network.h
M src/libosmo-mgcp/mgcp_network.c
M src/libosmo-mgcp/mgcp_protocol.c
3 files changed, 16 insertions(+), 5 deletions(-)

  neels: Looks good to me, but someone else must approve
  dexter: Looks good to me, approved
  Jenkins Builder: Verified

diff --git a/include/osmocom/mgcp/mgcp_network.h b/include/osmocom/mgcp/mgcp_network.h
index 1ed00e4..75b342d 100644
--- a/include/osmocom/mgcp/mgcp_network.h
+++ b/include/osmocom/mgcp/mgcp_network.h
@@ -132,6 +132,8 @@
 	char local_addr[INET6_ADDRSTRLEN];
+bool mgcp_rtp_end_remote_addr_available(const struct mgcp_rtp_end *rtp_end);
 struct mgcp_rtp_tap {
 	/* is this tap active (1) or not (0) */
 	int enabled;
diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 5b3ea51..d18c7cb 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -88,6 +88,11 @@
+bool mgcp_rtp_end_remote_addr_available(const struct mgcp_rtp_end *rtp_end)
+	return rtp_end->rtp_port && !addr_is_any(&rtp_end->addr);
 /*! Determine the local rtp bind IP-address.
  *  \param[out] addr caller provided memory to store the resulting IP-Address.
  *  \param[in] endp mgcp endpoint, that holds a copy of the VTY parameters.
diff --git a/src/libosmo-mgcp/mgcp_protocol.c b/src/libosmo-mgcp/mgcp_protocol.c
index 8d6f6f5..4fb93b0 100644
--- a/src/libosmo-mgcp/mgcp_protocol.c
+++ b/src/libosmo-mgcp/mgcp_protocol.c
@@ -990,8 +990,9 @@
 	/* Send dummy packet, see also comments in mgcp_keepalive_timer_cb() */
 	OSMO_ASSERT(trunk->keepalive_interval >= MGCP_KEEPALIVE_ONCE);
-	if (conn->conn->mode & MGCP_CONN_RECV_ONLY
-	    && trunk->keepalive_interval != MGCP_KEEPALIVE_NEVER)
+	if (conn->conn->mode & MGCP_CONN_RECV_ONLY &&
+	    mgcp_rtp_end_remote_addr_available(&conn->end) &&
+	    trunk->keepalive_interval != MGCP_KEEPALIVE_NEVER)
 		send_dummy(endp, conn);
@@ -1232,8 +1233,9 @@
 	/* Send dummy packet, see also comments in mgcp_keepalive_timer_cb() */
 	OSMO_ASSERT(endp->trunk->keepalive_interval >= MGCP_KEEPALIVE_ONCE);
-	if (conn->conn->mode & MGCP_CONN_RECV_ONLY
-	    && endp->trunk->keepalive_interval != MGCP_KEEPALIVE_NEVER)
+	if (conn->conn->mode & MGCP_CONN_RECV_ONLY &&
+	    mgcp_rtp_end_remote_addr_available(&conn->end) &&
+	    endp->trunk->keepalive_interval != MGCP_KEEPALIVE_NEVER)
 		send_dummy(endp, conn);
 	rate_ctr_inc(rate_ctr_group_get_ctr(rate_ctrs, MGCP_MDCX_SUCCESS));
@@ -1495,7 +1497,9 @@
 	for (i = 1; i < trunk->number_endpoints; ++i) {
 		struct mgcp_endpoint *endp = trunk->endpoints[i];
 		llist_for_each_entry(conn, &endp->conns, entry) {
-			if (conn->mode == MGCP_CONN_RECV_ONLY)
+			if (conn->type == MGCP_CONN_TYPE_RTP &&
+			    conn->mode == MGCP_CONN_RECV_ONLY &&
+			     mgcp_rtp_end_remote_addr_available(&conn->u.rtp.end))
 				send_dummy(endp, &conn->u.rtp);

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Gerrit-Project: osmo-mgw
Gerrit-Branch: master
Gerrit-Change-Id: I8ceafda691146823b12232b4a804b4ce74acbdc8
Gerrit-Change-Number: 24862
Gerrit-PatchSet: 4
Gerrit-Owner: pespin <pespin at>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: dexter <pmaier at>
Gerrit-Reviewer: neels <nhofmeyr at>
Gerrit-Reviewer: pespin <pespin at>
Gerrit-MessageType: merged
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