From: Holger Hans Peter Freyther <[email protected]>

There appears to be a leak of CIDs:
 <000b> mgcp_osmux.c:544 All Osmux circuits are in use!

There are paths that a CID had been requested and never released
of the NAT. Remember the allocated CID inside the endpoint so it
can always be released. It is using a new variable as the behavior
for the NAT and MGCP MGW is different.

Fixes: OW#1493
---
 openbsc/include/openbsc/mgcp_internal.h   |  2 ++
 openbsc/include/openbsc/osmux.h           |  2 ++
 openbsc/src/libmgcp/mgcp_osmux.c          | 13 +++++++++++++
 openbsc/src/libmgcp/mgcp_protocol.c       |  4 ++++
 openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c | 18 +++++++++---------
 5 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/openbsc/include/openbsc/mgcp_internal.h 
b/openbsc/include/openbsc/mgcp_internal.h
index 1f83659..8bb8f22 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -192,6 +192,8 @@ struct mgcp_endpoint {
                /* Osmux state: disabled, activating, active */
                enum osmux_state state;
                /* Allocated Osmux circuit ID for this endpoint */
+               uint8_t allocated_cid;
+               /* Used Osmux circuit ID for this endpoint */
                uint8_t cid;
                /* handle to batch messages */
                struct osmux_in_handle *in;
diff --git a/openbsc/include/openbsc/osmux.h b/openbsc/include/openbsc/osmux.h
index 88d045b..82b8fa3 100644
--- a/openbsc/include/openbsc/osmux.h
+++ b/openbsc/include/openbsc/osmux.h
@@ -14,6 +14,8 @@ int osmux_init(int role, struct mgcp_config *cfg);
 int osmux_enable_endpoint(struct mgcp_endpoint *endp, int role,
                          struct in_addr *addr, uint16_t port);
 void osmux_disable_endpoint(struct mgcp_endpoint *endp);
+void osmux_allocate_cid(struct mgcp_endpoint *endp);
+void osmux_release_cid(struct mgcp_endpoint *endp);

 int osmux_xfrm_to_rtp(struct mgcp_endpoint *endp, int type, char *buf, int rc);
 int osmux_xfrm_to_osmux(int type, char *buf, int rc, struct mgcp_endpoint 
*endp);
diff --git a/openbsc/src/libmgcp/mgcp_osmux.c b/openbsc/src/libmgcp/mgcp_osmux.c
index 30a81cb..2d39b2c 100644
--- a/openbsc/src/libmgcp/mgcp_osmux.c
+++ b/openbsc/src/libmgcp/mgcp_osmux.c
@@ -492,6 +492,19 @@ void osmux_disable_endpoint(struct mgcp_endpoint *endp)
        osmux_handle_put(endp->osmux.in);
 }

+void osmux_release_cid(struct mgcp_endpoint *endp)
+{
+       if (endp->osmux.allocated_cid >= 0)
+               osmux_put_cid(endp->osmux.allocated_cid);
+       endp->osmux.allocated_cid = -1;
+}
+
+void osmux_allocate_cid(struct mgcp_endpoint *endp)
+{
+       osmux_release_cid(endp);
+       endp->osmux.allocated_cid = osmux_get_cid();
+}
+
 /* We don't need to send the dummy load for osmux so often as another endpoint
  * may have already punched the hole in the firewall. This approach is simple
  * though.
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c 
b/openbsc/src/libmgcp/mgcp_protocol.c
index e2bda3a..42ce8bb 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -1314,6 +1314,7 @@ int mgcp_endpoints_allocate(struct mgcp_trunk_config 
*tcfg)
                return -1;

        for (i = 0; i < tcfg->number_endpoints; ++i) {
+               tcfg->endpoints[i].osmux.allocated_cid = -1;
                tcfg->endpoints[i].ci = CI_UNUSED;
                tcfg->endpoints[i].cfg = tcfg->cfg;
                tcfg->endpoints[i].tcfg = tcfg;
@@ -1354,6 +1355,9 @@ void mgcp_release_endp(struct mgcp_endpoint *endp)
        if (endp->osmux.state == OSMUX_STATE_ENABLED)
                osmux_disable_endpoint(endp);

+       /* release the circuit ID if it had been allocated */
+       osmux_release_cid(endp);
+
        memset(&endp->taps, 0, sizeof(endp->taps));
 }

diff --git a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c 
b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
index aad59d4..bd8f7a4 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
@@ -515,7 +515,6 @@ static int bsc_mgcp_policy_cb(struct mgcp_trunk_config 
*tcfg, int endpoint, int
        struct nat_sccp_connection *sccp;
        struct mgcp_endpoint *mgcp_endp;
        struct msgb *bsc_msg;
-       int osmux_cid = -1;

        nat = tcfg->cfg->data;
        bsc_endp = &nat->bsc_endpoints[endpoint];
@@ -555,8 +554,9 @@ static int bsc_mgcp_policy_cb(struct mgcp_trunk_config 
*tcfg, int endpoint, int
        /* Allocate a Osmux circuit ID */
        if (state == MGCP_ENDP_CRCX) {
                if (nat->mgcp_cfg->osmux && sccp->bsc->cfg->osmux) {
-                       osmux_cid = osmux_get_cid();
-                       if (osmux_cid < 0 && nat_osmux_only(nat->mgcp_cfg, 
sccp->bsc->cfg)) {
+                       osmux_allocate_cid(mgcp_endp);
+                       if (mgcp_endp->osmux.allocated_cid < 0 &&
+                               nat_osmux_only(nat->mgcp_cfg, sccp->bsc->cfg)) {
                                LOGP(DMGCP, LOGL_ERROR,
                                        "Rejecting usage of endpoint\n");
                                return MGCP_POLICY_REJECT;
@@ -567,7 +567,8 @@ static int bsc_mgcp_policy_cb(struct mgcp_trunk_config 
*tcfg, int endpoint, int
        /* we need to generate a new and patched message */
        bsc_msg = bsc_mgcp_rewrite((char *) nat->mgcp_msg, nat->mgcp_length,
                                   sccp->bsc_endp, mgcp_bts_src_addr(mgcp_endp),
-                                  mgcp_endp->bts_end.local_port, osmux_cid,
+                                  mgcp_endp->bts_end.local_port,
+                                  mgcp_endp->osmux.allocated_cid,
                                   &mgcp_endp->net_end.codec.payload_type,
                                   nat->sdp_ensure_amr_mode_set);
        if (!bsc_msg) {
@@ -587,10 +588,10 @@ static int bsc_mgcp_policy_cb(struct mgcp_trunk_config 
*tcfg, int endpoint, int
                /* Annotate the allocated Osmux CID until the bsc confirms that
                 * it agrees to use Osmux for this voice flow.
                 */
-               if (osmux_cid >= 0 &&
+               if (mgcp_endp->osmux.allocated_cid >= 0 &&
                    mgcp_endp->osmux.state != OSMUX_STATE_ENABLED) {
                        mgcp_endp->osmux.state = OSMUX_STATE_ACTIVATING;
-                       mgcp_endp->osmux.cid = osmux_cid;
+                       mgcp_endp->osmux.cid = mgcp_endp->osmux.allocated_cid;
                }

                socklen_t len = sizeof(sock);
@@ -612,7 +613,7 @@ static int bsc_mgcp_policy_cb(struct mgcp_trunk_config 
*tcfg, int endpoint, int

                /* libmgcp clears the MGCP endpoint for us */
                if (mgcp_endp->osmux.state == OSMUX_STATE_ENABLED)
-                       osmux_put_cid(mgcp_endp->osmux.cid);
+                       osmux_release_cid(mgcp_endp);

                return MGCP_POLICY_CONT;
        } else {
@@ -681,8 +682,7 @@ static void bsc_mgcp_osmux_confirm(struct mgcp_endpoint 
*endp, const char *str)
             osmux_cid);
        return;
 err:
-       osmux_put_cid(endp->osmux.cid);
-       endp->osmux.cid = -1;
+       osmux_release_cid(endp);
        endp->osmux.state = OSMUX_STATE_DISABLED;
 }

-- 
2.6.0

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