m3ua: Implement link bring-up and sending/receiving of data

the opc/dpc for ISUP is currently wrong. The send/recv path
for actual SCCP data is not tested.

1 files changed, 341 insertions, 2 deletions

diff --git a/src/sctp_m3ua_client.c b/src/sctp_m3ua_client.c
index 0cef103..dd378bb 100644
--- a/src/sctp_m3ua_client.c
+++ b/src/sctp_m3ua_client.c
@@ -18,6 +18,11 @@
 #include <sctp_m3ua.h>
 #include <cellmgr_debug.h>
 #include <string.h>
+#include <bsc_data.h>
+#include <mtp_level3.h>
+
+#include <osmocom/sigtran/xua_msg.h>
+#include <osmocom/sigtran/m3ua_types.h>
 
 #include <osmocom/core/talloc.h>
 
@@ -30,6 +35,20 @@
 #define notImplemented()	\
 		LOGP(DINP, LOGL_NOTICE, "%s not implemented.\n", __func__)
 
+
+/*
+ * State machine code
+ */
+static void m3ua_handle_aspsm(struct mtp_m3ua_client_link *link, struct xua_msg *msg);
+static void m3ua_handle_asptm(struct mtp_m3ua_client_link *link, struct xua_msg *msg);
+static void m3ua_handle_trans(struct mtp_m3ua_client_link *link, struct xua_msg *msg);
+static void m3ua_send_daud(struct mtp_m3ua_client_link *link, uint32_t pc);
+static void m3ua_send_aspup(struct mtp_m3ua_client_link *link);
+static void m3ua_send_aspac(struct mtp_m3ua_client_link *link);
+
+/*
+ * boilerplate
+ */
 static int m3ua_shutdown(struct mtp_link *mtp_link);
 static void m3ua_start(void *data);
 
@@ -51,7 +70,30 @@ static void fail_link(struct mtp_m3ua_client_link *link)
 static int m3ua_conn_handle(struct mtp_m3ua_client_link *link,
 				struct msgb *msg, struct sctp_sndrcvinfo *info)
 {
-	notImplemented();
+	struct xua_msg *m3ua;
+	m3ua = xua_from_msg(M3UA_VERSION, msg->len, msg->data);
+	if (!m3ua) {
+		LOGP(DINP, LOGL_ERROR, "Failed to parse the message.\n");
+		return -1;
+	}
+
+	switch (m3ua->hdr.msg_class) {
+	case M3UA_CLS_ASPSM:
+		m3ua_handle_aspsm(link, m3ua);
+		break;
+	case M3UA_CLS_ASPTM:
+		m3ua_handle_asptm(link, m3ua);
+		break;
+	case M3UA_CLS_TRANS:
+		m3ua_handle_trans(link, m3ua);
+		break;
+	default:
+		LOGP(DINP, LOGL_ERROR, "Unhandled msg_class %d\n",
+			m3ua->hdr.msg_class);
+		break;
+	}
+
+	xua_msg_free(m3ua);
 	return 0;
 }
 
@@ -70,6 +112,29 @@ static int m3ua_conn_write(struct osmo_fd *fd, struct msgb *msg)
 	return 0;
 }
 
+static int m3ua_conn_send(struct mtp_m3ua_client_link *link,
+			  struct xua_msg *m3ua,
+			  struct sctp_sndrcvinfo *info)
+{
+	struct msgb *msg;
+	msg = xua_to_msg(M3UA_VERSION, m3ua);
+	if (!msg)
+		return -1;
+
+	/* save the OOB data in front of the message */
+	msg->l2h = msg->data;
+	msgb_push(msg, sizeof(*info));
+	memcpy(msg->data, info, sizeof(*info));
+
+	if (osmo_wqueue_enqueue(&link->queue, msg) != 0) {
+		LOGP(DINP, LOGL_ERROR, "Failed to enqueue.\n");
+		msgb_free(msg);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int m3ua_conn_read(struct osmo_fd *fd)
 {
 	struct sockaddr_in addr;
@@ -161,11 +226,89 @@ static void m3ua_start(void *data)
 		close(sctp);
 		return fail_link(link);
 	}
+
+	/* begin the messages for bring-up */
+	m3ua_send_aspup(link);
 }
 
 static int m3ua_write(struct mtp_link *mtp_link, struct msgb *msg)
 {
-	notImplemented();
+	struct mtp_m3ua_client_link *link = mtp_link->data;
+	struct sctp_sndrcvinfo info;
+	struct xua_msg *m3ua;
+	struct mtp_level_3_hdr *mtp_hdr;
+	struct m3ua_protocol_data proto_data;
+	uint8_t *proto_start;
+
+	if (!link->asptm_active) {
+		LOGP(DINP, LOGL_ERROR, "ASP not ready  for %d/%s of %d/%s.\n",
+			mtp_link->nr, mtp_link->name, mtp_link->set->nr,
+			mtp_link->set->name);
+		goto clean;
+	}
+
+	/*
+	 * TODO.. we could enhance the structure of mtp_link to
+	 * have function pointers for operations like SLTM instead
+	 * of doing what we do here.
+	 * The entire m3ua episode (code + reading the spec) had a
+	 * budget of < 2 man days so the amount of architecture changes
+	 * we can do.
+	 */
+
+	/* TODO.. need to terminate MTPL3 locally... */
+
+	/* TODO.. extract MTP information.. */
+	mtp_hdr = (struct mtp_level_3_hdr *) msg->l2h;
+	switch (mtp_hdr->ser_ind) {
+	case MTP_SI_MNT_SNM_MSG:
+	case MTP_SI_MNT_REG_MSG:
+		LOGP(DINP, LOGL_ERROR,
+			"Dropping SNM/REG/ISUP/??? message %d\n", mtp_hdr->ser_ind);
+		goto clean;
+		break;
+	case MTP_SI_MNT_ISUP:
+	case MTP_SI_MNT_SCCP:
+	default:
+		/* TODO... read OPC/DPC from message.. */
+		memset(&proto_data, 0, sizeof(proto_data));
+		proto_data.opc = htonl(mtp_link->set->sccp_opc);
+		proto_data.dpc = htonl(mtp_link->set->sccp_dpc == -1 ?
+					mtp_link->set->sccp_dpc : mtp_link->set->dpc);
+		proto_data.sls = MTP_LINK_SLS(mtp_hdr->addr);
+		proto_data.si = mtp_hdr->ser_ind;
+		proto_data.ni = mtp_link->set->ni;
+
+		msg->l3h = mtp_hdr->data;
+		msgb_pull_to_l3(msg);
+		proto_start = msgb_push(msg, sizeof(proto_data));
+		memcpy(proto_start, &proto_data, sizeof(proto_data));
+		break;
+	};
+
+	m3ua = xua_msg_alloc();
+	if (!m3ua)
+		goto clean;
+
+	mtp_handle_pcap(mtp_link, NET_OUT, msg->data, msg->len);
+
+	m3ua->hdr.msg_class = M3UA_CLS_TRANS;
+	m3ua->hdr.msg_type = M3UA_TRANS_DATA;
+
+	/*
+	 * Modify the data...to create a true protocol data..
+	 */
+	xua_msg_add_data(m3ua, M3UA_TAG_PROTO_DATA, msg->len, msg->data);
+
+	memset(&info, 0, sizeof(info));
+	info.sinfo_stream = 0;
+	info.sinfo_assoc_id = 1;
+	info.sinfo_ppid = htonl(SCTP_PPID_M3UA);
+
+	m3ua_conn_send(link, m3ua, &info);
+	xua_msg_free(m3ua);
+
+clean:
 	msgb_free(msg);
 	return 0;
 }
@@ -180,6 +323,8 @@ static int m3ua_shutdown(struct mtp_link *mtp_link)
 		link->queue.bfd.fd = -1;
 	}
 	osmo_wqueue_clear(&link->queue);
+	link->aspsm_active = 0;
+	link->asptm_active = 0;
 	return 0;
 }
 
@@ -227,3 +372,197 @@ struct mtp_m3ua_client_link *mtp_m3ua_client_link_init(struct mtp_link *blnk)
 	lnk->queue.bfd.fd = -1;
 	return lnk;
 }
+
+
+/*
+ * asp handling
+ */
+static void m3ua_send_aspup(struct mtp_m3ua_client_link *link)
+{
+	struct sctp_sndrcvinfo info;
+	struct xua_msg *aspup;
+	uint32_t asp_ident;
+
+	aspup = xua_msg_alloc();
+	if (!aspup) {
+		fail_link(link);
+		return;
+	}
+
+	memset(&info, 0, sizeof(info));
+	info.sinfo_stream = 0;
+	info.sinfo_assoc_id = 1;
+	info.sinfo_ppid = htonl(SCTP_PPID_M3UA);
+
+	aspup->hdr.msg_class = M3UA_CLS_ASPSM;
+	aspup->hdr.msg_type = M3UA_ASPSM_UP;
+
+	asp_ident = htonl(link->link_index);
+	xua_msg_add_data(aspup, MUA_TAG_ASP_IDENT, 4, (uint8_t *) &asp_ident);
+
+	m3ua_conn_send(link, aspup, &info);
+	xua_msg_free(aspup);
+}
+
+static void m3ua_send_aspac(struct mtp_m3ua_client_link *link)
+{
+	struct sctp_sndrcvinfo info;
+	struct xua_msg *aspac;
+	uint32_t routing_ctx;
+	uint32_t traffic_mode;
+
+	aspac = xua_msg_alloc();
+	if (!aspac) {
+		fail_link(link);
+		return;
+	}
+
+	memset(&info, 0, sizeof(info));
+	info.sinfo_stream = 0;
+	info.sinfo_assoc_id = 1;
+	info.sinfo_ppid = htonl(SCTP_PPID_M3UA);
+
+	aspac->hdr.msg_class = M3UA_CLS_ASPTM;
+	aspac->hdr.msg_type = M3UA_ASPTM_ACTIV;
+
+	traffic_mode = htonl(2);
+	xua_msg_add_data(aspac, 11, 4, (uint8_t *) &traffic_mode);
+
+	routing_ctx = htonl(link->routing_context);
+	xua_msg_add_data(aspac, MUA_TAG_ROUTING_CTX, 4, (uint8_t *) &routing_ctx);
+
+	m3ua_conn_send(link, aspac, &info);
+	xua_msg_free(aspac);
+}
+
+static void m3ua_send_daud(struct mtp_m3ua_client_link *link, uint32_t dpc)
+{
+	struct sctp_sndrcvinfo info;
+	struct xua_msg *daud;
+	uint32_t routing_ctx;
+
+	daud = xua_msg_alloc();
+	if (!daud) {
+		fail_link(link);
+		return;
+	}
+
+	memset(&info, 0, sizeof(info));
+	info.sinfo_stream = 0;
+	info.sinfo_assoc_id = 1;
+	info.sinfo_ppid = htonl(SCTP_PPID_M3UA);
+
+	daud->hdr.msg_class = M3UA_CLS_SSNM;
+	daud->hdr.msg_type = M3UA_SSNM_DAUD;
+
+	routing_ctx = htonl(link->routing_context);
+	xua_msg_add_data(daud, MUA_TAG_ROUTING_CTX, 4, (uint8_t *) &routing_ctx);
+
+	dpc = htonl(dpc);
+	xua_msg_add_data(daud, MUA_TAG_AFF_PC, 4, (uint8_t *) &dpc);
+
+	m3ua_conn_send(link, daud, &info);
+	xua_msg_free(daud);
+}
+
+static void m3ua_handle_aspsm(struct mtp_m3ua_client_link *link, struct xua_msg *m3ua)
+{
+	switch (m3ua->hdr.msg_type) {
+	case M3UA_ASPSM_UP_ACK:
+		LOGP(DINP, LOGL_NOTICE, "Received ASP_UP_ACK.. sending ASPAC\n");
+		link->aspsm_active = 1;
+		m3ua_send_aspac(link);
+		break;
+	default:
+		LOGP(DINP, LOGL_ERROR, "Unhandled msg_type %d\n",
+			m3ua->hdr.msg_type);
+		break;
+	}
+}
+
+static void m3ua_handle_asptm(struct mtp_m3ua_client_link *link, struct xua_msg *m3ua)
+{
+	switch (m3ua->hdr.msg_type) {
+	case M3UA_ASPTM_ACTIV_ACK:
+		LOGP(DINP, LOGL_NOTICE, "Received ASPAC_ACK.. taking link up\n");
+		link->asptm_active = 1;
+		mtp_link_up(link->base);
+		m3ua_send_daud(link, link->base->set->dpc);
+		if (link->base->set->sccp_dpc != -1)
+			m3ua_send_daud(link, link->base->set->sccp_dpc);
+		break;
+	default:
+		LOGP(DINP, LOGL_ERROR, "Unhandled msg_type %d\n",
+			m3ua->hdr.msg_type);
+		break;
+	}
+}
+
+static void m3ua_handle_trans(struct mtp_m3ua_client_link *link, struct xua_msg *m3ua)
+{
+	struct msgb *msg;
+	struct xua_msg_part *data;
+	struct mtp_link *mtp_link;
+	struct m3ua_protocol_data *proto;
+	struct mtp_level_3_hdr *mtp_hdr;
+	uint32_t opc, dpc;
+	uint8_t sls, si;
+
+	mtp_link = link->base;
+
+	/* ignore everything if the link is blocked */
+	if (mtp_link->blocked)
+		return;
+
+	if (m3ua->hdr.msg_type != M3UA_TRANS_DATA) {
+		LOGP(DINP, LOGL_ERROR, "msg_type(%d) is not known. Ignoring\n",
+			m3ua->hdr.msg_type);
+		return;
+	}
+
+	data = xua_msg_find_tag(m3ua, M3UA_TAG_PROTO_DATA);
+	if (!data) {
+		LOGP(DINP, LOGL_ERROR, "No PROTO_DATA in DATA message.\n");
+		return;
+	}
+
+	if (data->len > 2048) {
+		LOGP(DINP, LOGL_ERROR, "TOO much data for us to handle.\n");
+		return;
+	}
+
+	if (data->len < sizeof(struct m3ua_protocol_data)) {
+		LOGP(DINP, LOGL_ERROR, "Too little data..\n");
+		return;
+	}
+
+	msg = msgb_alloc(2048, "m3ua-data");
+	if (!msg) {
+		LOGP(DINP, LOGL_ERROR, "Failed to allocate storage.\n");
+		return;
+	}
+
+	msg->l2h = msgb_put(msg, data->len);
+	memcpy(msg->l2h, data->dat, data->len);
+
+	proto = (struct m3ua_protocol_data *) msg->l2h;
+	opc = ntohl(proto->opc);
+	dpc = ntohl(proto->dpc);
+	sls = proto->sls;
+	si = proto->si;
+	LOGP(DINP, LOGL_DEBUG, "Got data for OPC(%d)/DPC(%d)/SLS(%d) len(%d)\n",
+		opc, dpc, sls, msgb_l2len(msg) - sizeof(*proto));
+
+
+	/* put a MTP3 header in front */
+	msg->l3h = proto->data;
+	msgb_pull_to_l3(msg);
+	msg->l2h = msgb_push(msg, sizeof(*mtp_hdr));
+	mtp_hdr = (struct mtp_level_3_hdr *) msg->l2h;
+	mtp_hdr->ser_ind = si;
+	mtp_hdr->addr = MTP_ADDR(sls % 16, dpc, opc);
+
+	mtp_handle_pcap(mtp_link, NET_IN, msg->l2h, msgb_l2len(msg));
+	mtp_link_set_data(mtp_link, msg);
+	msgb_free(msg);
+}