Implement AoIP, port to M3UA SIGTRAN (large addition and refactoring)

This was originally a long series of commits converging to the final result
seen in this patch. It does not make much sense to review the smaller steps'
trial and error, we need to review this entire change as a whole.

Implement AoIP in osmo-msc and osmo-bsc.

Change over to the new libosmo-sigtran API with support for proper
SCCP/M3UA/SCTP stacking, as mandated by 3GPP specifications for the IuCS and
IuPS interfaces.

From here on, a separate osmo-stp process is required for SCCP routing between
OsmoBSC / OsmoHNBGW <-> OsmoMSC / OsmoSGSN

jenkins.sh: build from libosmo-sccp and osmo-iuh master branches now for new
M3UA SIGTRAN.

Patch-by: pmaier, nhofmeyr, laforge
Change-Id: I5ae4e05ee7c57cad341ea5e86af37c1f6b0ffa77

1 files changed, 201 insertions, 6 deletions

diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index 28cba5b85..b6746a564 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -79,6 +79,8 @@
 #include <openbsc/iu.h>
 #endif
 
+#include <openbsc/a_iface.h>
+
 #include <assert.h>
 
 
@@ -1267,6 +1269,8 @@ static int mncc_recvmsg(struct gsm_network *net, struct gsm_trans *trans,
 	struct msgb *msg;
 	unsigned char *data;
 
+	DEBUGP(DMNCC, "transmit message %s\n", get_mncc_name(msg_type));
+
 #if BEFORE_MSCSPLIT
 	/* Re-enable this log output once we can obtain this information via
 	 * A-interface, see OS#2391. */
@@ -1324,6 +1328,9 @@ void _gsm48_cc_trans_free(struct gsm_trans *trans)
 {
 	gsm48_stop_cc_timer(trans);
 
+	/* Make sure call also gets released on the mgcp side */
+	msc_call_release(trans);
+
 	/* send release to L4, if callref still exists */
 	if (trans->callref) {
 		/* Ressource unavailable */
@@ -1549,6 +1556,12 @@ static int gsm48_cc_rx_setup(struct gsm_trans *trans, struct msgb *msg)
 		setup.fields |= MNCC_F_BEARER_CAP;
 		gsm48_decode_bearer_cap(&setup.bearer_cap,
 				  TLVP_VAL(&tp, GSM48_IE_BEARER_CAP)-1);
+
+		/* Create a copy of the bearer capability
+		 * in the transaction struct, so we can use
+		 * this information later */
+		memcpy(&trans->bearer_cap,&setup.bearer_cap,
+		       sizeof(trans->bearer_cap));
 	}
 	/* facility */
 	if (TLVP_PRESENT(&tp, GSM48_IE_FACILITY)) {
@@ -1682,6 +1695,7 @@ static int gsm48_cc_rx_call_conf(struct gsm_trans *trans, struct msgb *msg)
 	unsigned int payload_len = msgb_l3len(msg) - sizeof(*gh);
 	struct tlv_parsed tp;
 	struct gsm_mncc call_conf;
+	int rc;
 
 	gsm48_stop_cc_timer(trans);
 	gsm48_start_cc_timer(trans, 0x310, GSM48_T310);
@@ -1702,6 +1716,12 @@ static int gsm48_cc_rx_call_conf(struct gsm_trans *trans, struct msgb *msg)
 		call_conf.fields |= MNCC_F_BEARER_CAP;
 		gsm48_decode_bearer_cap(&call_conf.bearer_cap,
 				  TLVP_VAL(&tp, GSM48_IE_BEARER_CAP)-1);
+
+		/* Create a copy of the bearer capability
+		 * in the transaction struct, so we can use
+		 * this information later */
+		memcpy(&trans->bearer_cap,&call_conf.bearer_cap,
+		       sizeof(trans->bearer_cap));
 	}
 	/* cause */
 	if (TLVP_PRESENT(&tp, GSM48_IE_CAUSE)) {
@@ -1721,7 +1741,18 @@ static int gsm48_cc_rx_call_conf(struct gsm_trans *trans, struct msgb *msg)
 
 	new_cc_state(trans, GSM_CSTATE_MO_TERM_CALL_CONF);
 
-	msc_call_assignment(trans);
+	/* Assign call (if not done yet) */
+	if (trans->assignment_done == false) {
+		rc = msc_call_assignment(trans);
+		trans->assignment_done = true;
+	}
+	else
+		rc = 0;
+
+	/* don't continue, if there were problems with
+	 * the call assignment. */
+	if (rc)
+		return rc;
 
 	return mncc_recvmsg(trans->net, trans, MNCC_CALL_CONF_IND,
 			    &call_conf);
@@ -1752,7 +1783,15 @@ static int gsm48_cc_tx_call_proc_and_assign(struct gsm_trans *trans, void *arg)
 	if (rc)
 		return rc;
 
-	return msc_call_assignment(trans);
+	/* Assign call (if not done yet) */
+	if (trans->assignment_done == false) {
+		rc = msc_call_assignment(trans);
+		trans->assignment_done = true;
+	}
+	else
+		rc = 0;
+
+	return rc;
 }
 
 static int gsm48_cc_rx_alerting(struct gsm_trans *trans, struct msgb *msg)
@@ -2398,6 +2437,12 @@ static int gsm48_cc_rx_modify(struct gsm_trans *trans, struct msgb *msg)
 		modify.fields |= MNCC_F_BEARER_CAP;
 		gsm48_decode_bearer_cap(&modify.bearer_cap,
 				  TLVP_VAL(&tp, GSM48_IE_BEARER_CAP)-1);
+
+		/* Create a copy of the bearer capability
+		 * in the transaction struct, so we can use
+		 * this information later */
+		memcpy(&trans->bearer_cap,&modify.bearer_cap,
+		       sizeof(trans->bearer_cap));
 	}
 
 	new_cc_state(trans, GSM_CSTATE_MO_ORIG_MODIFY);
@@ -2440,6 +2485,12 @@ static int gsm48_cc_rx_modify_complete(struct gsm_trans *trans, struct msgb *msg
 		modify.fields |= MNCC_F_BEARER_CAP;
 		gsm48_decode_bearer_cap(&modify.bearer_cap,
 				  TLVP_VAL(&tp, GSM48_IE_BEARER_CAP)-1);
+
+		/* Create a copy of the bearer capability
+		 * in the transaction struct, so we can use
+		 * this information later */
+		memcpy(&trans->bearer_cap,&modify.bearer_cap,
+		       sizeof(trans->bearer_cap));
 	}
 
 	new_cc_state(trans, GSM_CSTATE_ACTIVE);
@@ -2480,6 +2531,12 @@ static int gsm48_cc_rx_modify_reject(struct gsm_trans *trans, struct msgb *msg)
 		modify.fields |= GSM48_IE_BEARER_CAP;
 		gsm48_decode_bearer_cap(&modify.bearer_cap,
 				  TLVP_VAL(&tp, GSM48_IE_BEARER_CAP)-1);
+
+		/* Create a copy of the bearer capability
+		 * in the transaction struct, so we can use
+		 * this information later */
+		memcpy(&trans->bearer_cap,&modify.bearer_cap,
+		       sizeof(trans->bearer_cap));
 	}
 	/* cause */
 	if (TLVP_PRESENT(&tp, GSM48_IE_CAUSE)) {
@@ -2582,6 +2639,139 @@ static int gsm48_cc_rx_userinfo(struct gsm_trans *trans, struct msgb *msg)
 	return mncc_recvmsg(trans->net, trans, MNCC_USERINFO_IND, &user);
 }
 
+static void mncc_recv_rtp(struct gsm_network *net, uint32_t callref,
+		int cmd, uint32_t addr, uint16_t port, uint32_t payload_type,
+		uint32_t payload_msg_type)
+{
+	uint8_t data[sizeof(struct gsm_mncc)];
+	struct gsm_mncc_rtp *rtp;
+
+	memset(&data, 0, sizeof(data));
+	rtp = (struct gsm_mncc_rtp *) &data[0];
+
+	rtp->callref = callref;
+	rtp->msg_type = cmd;
+	rtp->ip = addr;
+	rtp->port = port;
+	rtp->payload_type = payload_type;
+	rtp->payload_msg_type = payload_msg_type;
+	mncc_recvmsg(net, NULL, cmd, (struct gsm_mncc *)data);
+}
+
+static void mncc_recv_rtp_sock(struct gsm_network *net, struct gsm_trans *trans, int cmd)
+{
+	int msg_type;
+
+	/* FIXME This has to be set to some meaningful value.
+	 * Possible options are:
+	 * GSM_TCHF_FRAME, GSM_TCHF_FRAME_EFR,
+	 * GSM_TCHH_FRAME, GSM_TCH_FRAME_AMR
+	 * (0 if unknown) */
+	msg_type = GSM_TCHF_FRAME;
+
+	uint32_t addr = mgcpgw_client_remote_addr_n(net->mgcpgw.client);
+	uint16_t port = trans->conn->rtp.port_cn;
+
+	/* FIXME: This has to be set to some meaningful value,
+	 * before the MSC-Split, this value was pulled from
+	 * lchan->abis_ip.rtp_payload */
+	uint32_t payload_type = 0;
+
+	return mncc_recv_rtp(net, trans->callref, cmd,
+			addr,
+			port,
+		        payload_type,
+			msg_type);
+}
+
+static void mncc_recv_rtp_err(struct gsm_network *net, uint32_t callref, int cmd)
+{
+	return mncc_recv_rtp(net, callref, cmd, 0, 0, 0, 0);
+}
+
+static int tch_rtp_create(struct gsm_network *net, uint32_t callref)
+{
+	struct gsm_trans *trans;
+	int rc;
+
+	/* Find callref */
+	trans = trans_find_by_callref(net, callref);
+	if (!trans) {
+		LOGP(DMNCC, LOGL_ERROR, "RTP create for non-existing trans\n");
+		mncc_recv_rtp_err(net, callref, MNCC_RTP_CREATE);
+		return -EIO;
+	}
+	log_set_context(LOG_CTX_VLR_SUBSCR, trans->vsub);
+	if (!trans->conn) {
+		LOGP(DMNCC, LOGL_NOTICE, "RTP create for trans without conn\n");
+		mncc_recv_rtp_err(net, callref, MNCC_RTP_CREATE);
+		return 0;
+	}
+
+	trans->conn->mncc_rtp_bridge = 1;
+
+	/* When we call msc_call_assignment() we will trigger, depending
+	 * on the RAN type the call assignment on the A or Iu interface.
+	 * msc_call_assignment() also takes care about sending the CRCX
+	 * command to the MGCP-GW. The CRCX will return the port number,
+	 * where the PBX (e.g. Asterisk) will send its RTP stream to. We
+	 * have to return this port number back to the MNCC by sending
+	 * it back with the TCH_RTP_CREATE message. To make sure that
+	 * this message is sent AFTER the response to CRCX from the
+	 * MGCP-GW has arrived, we need will instruct msc_call_assignment()
+	 * to take care of this by setting trans->tch_rtp_create to true.
+	 * This will make sure that gsm48_tch_rtp_create() (below) is
+	 * called as soon as the local port number has become known. */
+	trans->tch_rtp_create = true;
+
+	/* Assign call (if not done yet) */
+	if (trans->assignment_done == false) {
+		rc = msc_call_assignment(trans);
+		trans->assignment_done = true;
+	}
+	else
+		rc = 0;
+
+	return rc;
+}
+
+/* Trigger TCH_RTP_CREATE acknowledgement */
+int gsm48_tch_rtp_create(struct gsm_trans *trans)
+{
+	/* This function is called as soon as the port, on which the
+	 * mgcp-gw expects the incoming RTP stream from the remote
+	 * end (e.g. Asterisk) is known. */
+
+	struct gsm_subscriber_connection *conn = trans->conn;
+	struct gsm_network *network = conn->network;
+
+	mncc_recv_rtp_sock(network, trans, MNCC_RTP_CREATE);
+	return 0;
+}
+
+static int tch_rtp_connect(struct gsm_network *net, void *arg)
+{
+	struct gsm_trans *trans;
+	struct gsm_mncc_rtp *rtp = arg;
+
+	/* Find callref */
+	trans = trans_find_by_callref(net, rtp->callref);
+	if (!trans) {
+		LOGP(DMNCC, LOGL_ERROR, "RTP connect for non-existing trans\n");
+		mncc_recv_rtp_err(net, rtp->callref, MNCC_RTP_CONNECT);
+		return -EIO;
+	}
+	log_set_context(LOG_CTX_VLR_SUBSCR, trans->vsub);
+	if (!trans->conn) {
+		LOGP(DMNCC, LOGL_ERROR, "RTP connect for trans without conn\n");
+		mncc_recv_rtp_err(net, rtp->callref, MNCC_RTP_CONNECT);
+		return 0;
+	}
+
+	msc_call_connect(trans,rtp->port,rtp->ip);
+	return 0;
+}
+
 static struct downstate {
 	uint32_t	states;
 	int		type;
@@ -2657,11 +2847,16 @@ int mncc_tx_to_cc(struct gsm_network *net, int msg_type, void *arg)
 		if (rc < 0)
 			disconnect_bridge(net, arg, -rc);
 		return rc;
-	case MNCC_FRAME_DROP:
-	case MNCC_FRAME_RECV:
 	case MNCC_RTP_CREATE:
+		return tch_rtp_create(net, data->callref);
 	case MNCC_RTP_CONNECT:
+		return tch_rtp_connect(net, arg);
 	case MNCC_RTP_FREE:
+		/* unused right now */
+		return -EIO;
+
+	case MNCC_FRAME_DROP:
+	case MNCC_FRAME_RECV:
 	case GSM_TCHF_FRAME:
 	case GSM_TCHF_FRAME_EFR:
 	case GSM_TCHH_FRAME:
@@ -3211,8 +3406,8 @@ static int msc_vlr_set_ciph_mode(void *msc_conn_ref,
 	case RAN_GERAN_A:
 		DEBUGP(DMM, "-> CIPHER MODE COMMAND %s\n",
 		       vlr_subscr_name(conn->vsub));
-		return msc_gsm0808_tx_cipher_mode(conn, ciph, tuple->vec.kc, 8,
-						  retrieve_imeisv);
+		return a_iface_tx_cipher_mode(conn, ciph, tuple->vec.kc, 8,
+					      retrieve_imeisv);
 	case RAN_UTRAN_IU:
 #ifdef BUILD_IU
 		DEBUGP(DMM, "-> SECURITY MODE CONTROL %s\n",