mgcp: Send RTP keepalive dummy packets to net
So far, a single dummy packet has been sent immediately after the
reception of a MDCX message. There is no dedicated keep alive
mechanism (it just worked because the audio from the MS has always
been forwarded to the NAT until the 'mgcp: Set output_enabled flags
based on the MGCP mode' patch).
This patch adds explicit, timer based keep alive handling that can be
enable per trunk. A VTY command 'rtp keep-alive' command is added for
configuration which can be used to set the interval in seconds, to
send a single packet after the reception of a CRCX/MDCX when RTP data
from the net is expected ('once'), or to disable the feature
completely ('no rtp keep-alive'). In 'send-recv' connections, only
the initial packet is sent if enabled (even when an interval has been
configured). The default is 'once'.
Note that this removes the mgcp_change_cb() from mgcp_main.c.
Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index b55da37..9996ba7 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -877,6 +877,9 @@
if (p->cfg->change_cb)
p->cfg->change_cb(tcfg, ENDPOINT_NUMBER(endp), MGCP_ENDP_CRCX);
+ if (endp->bts_end.output_enabled && tcfg->keepalive_interval != 0)
+ mgcp_send_dummy(endp);
+
create_transcoder(endp);
return create_response_with_sdp(endp, "CRCX", p->trans);
error2:
@@ -975,6 +978,10 @@
ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr), ntohs(endp->net_end.rtp_port));
if (p->cfg->change_cb)
p->cfg->change_cb(endp->tcfg, ENDPOINT_NUMBER(endp), MGCP_ENDP_MDCX);
+
+ if (endp->bts_end.output_enabled && endp->tcfg->keepalive_interval != 0)
+ mgcp_send_dummy(endp);
+
if (silent)
goto out_silent;
@@ -1127,6 +1134,40 @@
create_err_response(p->endp, res, "RQNT", p->trans);
}
+static void mgcp_keepalive_timer_cb(void *_tcfg)
+{
+ struct mgcp_trunk_config *tcfg = _tcfg;
+ int i;
+ LOGP(DMGCP, LOGL_DEBUG, "Triggered trunk %d keepalive timer.\n",
+ tcfg->trunk_nr);
+
+ if (tcfg->keepalive_interval <= 0)
+ return;
+
+ for (i = 1; i < tcfg->number_endpoints; ++i) {
+ struct mgcp_endpoint *endp = &tcfg->endpoints[i];
+ if (endp->conn_mode == MGCP_CONN_RECV_ONLY)
+ mgcp_send_dummy(endp);
+ }
+
+ LOGP(DMGCP, LOGL_DEBUG, "Rescheduling trunk %d keepalive timer.\n",
+ tcfg->trunk_nr);
+ osmo_timer_schedule(&tcfg->keepalive_timer, tcfg->keepalive_interval, 0);
+}
+
+void mgcp_trunk_set_keepalive(struct mgcp_trunk_config *tcfg, int interval)
+{
+ tcfg->keepalive_interval = interval;
+ tcfg->keepalive_timer.data = tcfg;
+ tcfg->keepalive_timer.cb = mgcp_keepalive_timer_cb;
+
+ if (interval <= 0)
+ osmo_timer_del(&tcfg->keepalive_timer);
+ else
+ osmo_timer_schedule(&tcfg->keepalive_timer,
+ tcfg->keepalive_interval, 0);
+}
+
struct mgcp_config *mgcp_config_alloc(void)
{
struct mgcp_config *cfg;
@@ -1153,6 +1194,7 @@
cfg->trunk.audio_payload = 126;
cfg->trunk.audio_send_ptime = 1;
cfg->trunk.omit_rtcp = 0;
+ mgcp_trunk_set_keepalive(&cfg->trunk, MGCP_KEEPALIVE_ONCE);
INIT_LLIST_HEAD(&cfg->trunks);
@@ -1177,6 +1219,7 @@
trunk->audio_send_ptime = 1;
trunk->number_endpoints = 33;
trunk->omit_rtcp = 0;
+ mgcp_trunk_set_keepalive(trunk, MGCP_KEEPALIVE_ONCE);
llist_add_tail(&trunk->entry, &cfg->trunks);
return trunk;
}