[nat] Send a RSIP down to the BSC after it connects

Make sure the MGCP attached to the BSC is resetting all
endpoints whenever the BSC is connecting to us as we assume
that all endpoints are available.

2 files changed, 43 insertions, 1 deletions

diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index ab80cb401..835a2ae88 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -35,7 +35,7 @@
 #define DIR_BSC 1
 #define DIR_MSC 2
 
-#define NAT_IPAC_PROTO_MGCP
+#define NAT_IPAC_PROTO_MGCP	0xfc
 
 struct bsc_nat;
 
@@ -176,6 +176,7 @@ struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *, struct bsc_nat
 /**
  * MGCP/Audio handling
  */
+int bsc_write_mgcp(struct bsc_connection *bsc, const u_int8_t *data, unsigned int length);
 int bsc_mgcp_assign(struct sccp_connections *, struct msgb *msg);
 void bsc_mgcp_clear(struct sccp_connections *);
 
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index e8ba42802..b3754da43 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -127,6 +127,15 @@ static void send_id_req(struct bsc_connection *bsc)
 	bsc_write(bsc, id_req, sizeof(id_req));
 }
 
+static void send_mgcp_reset(struct bsc_connection *bsc)
+{
+	static const u_int8_t mgcp_reset[] = {
+	    "RSIP 1 13@mgw MGCP 1.0\r\n"
+	};
+
+	bsc_write_mgcp(bsc, mgcp_reset, sizeof mgcp_reset - 1);
+}
+
 /*
  * Below is the handling of messages coming
  * from the MSC and need to be forwarded to
@@ -166,6 +175,37 @@ static void bsc_write(struct bsc_connection *bsc, const u_int8_t *data, unsigned
 	}
 }
 
+int bsc_write_mgcp(struct bsc_connection *bsc, const u_int8_t *data, unsigned int length)
+{
+	struct msgb *msg;
+
+	if (length > 4096 - 128) {
+		LOGP(DINP, LOGL_ERROR, "Can not send message of that size.\n");
+		return -1;
+	}
+
+	msg = msgb_alloc_headroom(4096, 128, "to-bsc");
+	if (!msg) {
+		LOGP(DINP, LOGL_ERROR, "Failed to allocate memory for BSC msg.\n");
+		return -1;
+	}
+
+	/* copy the data */
+	msg->l3h = msgb_put(msg, length);
+	memcpy(msg->l3h, data, length);
+
+	/* prepend the header */
+	ipaccess_prepend_header(msg, NAT_IPAC_PROTO_MGCP);
+
+	if (write_queue_enqueue(&bsc->write_queue, msg) != 0) {
+		LOGP(DINP, LOGL_ERROR, "Failed to enqueue the write.\n");
+		msgb_free(msg);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int forward_sccp_to_bts(struct msgb *msg)
 {
 	struct sccp_connections *con;
@@ -558,6 +598,7 @@ static int ipaccess_listen_bsc_cb(struct bsc_fd *bfd, unsigned int what)
 	llist_add(&bsc->list_entry, &nat->bsc_connections);
 	send_id_ack(bsc);
 	send_id_req(bsc);
+	send_mgcp_reset(bsc);
 
 	/*
 	 * start the hangup timer