1 files changed, 122 insertions, 9 deletions

diff --git a/src/osmo-bsc/osmo_bsc_mgcp.c b/src/osmo-bsc/osmo_bsc_mgcp.c
index bec793032..d7de4d264 100644
--- a/src/osmo-bsc/osmo_bsc_mgcp.c
+++ b/src/osmo-bsc/osmo_bsc_mgcp.c
@@ -2,6 +2,7 @@
  * SCCPlite MGCP handling
  *
  * (C) 2018 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2023 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -19,6 +20,15 @@
  *
  */
 
+#include <string.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/sockaddr_str.h>
+#include <osmocom/mgcp_client/mgcp_client_endpoint_fsm.h>
+#include <osmocom/mgcp_client/mgcp_client.h>
+
 #include <osmocom/bsc/bsc_msc_data.h>
 #include <osmocom/bsc/osmo_bsc.h>
 #include <osmocom/bsc/gsm_data.h>
@@ -33,33 +43,136 @@
 static struct bsc_msc_data *msc_from_asp(struct osmo_ss7_asp *asp)
 {
 	int msc_nr;
+	const char *asp_name = osmo_ss7_asp_get_name(asp);
 	/* this is rather ugly, as we of course have MTP-level routing between
 	 * the local SCCP user (BSC) and the AS/ASPs.  However, for the most simple
 	 * SCCPlite case, there is a 1:1 mapping between ASP and AS, and using
 	 * the libosmo-sigtran "simple client", the names are "as[p]-clnt-msc-%u",
 	 * as set in osmo_bsc_sigtran_init() */
-	if (sscanf(asp->cfg.name, "asp-clnt-msc-%u", &msc_nr) != 1) {
-		LOGP(DMSC, LOGL_ERROR, "Cannot find to which MSC the ASP %s belongs\n", asp->cfg.name);
+	if (!asp_name || sscanf(asp_name, "asp-clnt-msc-%u", &msc_nr) != 1) {
+		LOGP(DMSC, LOGL_ERROR, "Cannot find to which MSC the ASP '%s' belongs\n", asp_name);
 		return NULL;
 	}
 	return osmo_msc_data_find(bsc_gsmnet, msc_nr);
 }
 
+/* negative on error, zero upon success */
+static int parse_local_endpoint_name(char *buf, size_t buf_len, const char *data)
+{
+	char line[1024];
+	char *epstart, *sep;
+	const char *start = data;
+	char *eol = strpbrk(start, "\r\n");
+
+	if (!eol)
+		return -1;
+
+	if (eol - start > sizeof(line))
+		return -1;
+	memcpy(line, start, eol - start);
+	line[eol - start] = '\0';
+
+	if (!(epstart = strchr(line, ' ')))
+		return -1;
+	epstart++;
+	/* epstart now points to trans */
+
+	if (!(epstart = strchr(epstart, ' ')))
+		return -1;
+	epstart++;
+	/* epstart now points to endpoint */
+	if (!(sep = strchr(epstart, '@')))
+		return -1;
+	if (sep - epstart >= buf_len)
+		return -1;
+
+	*sep = '\0';
+	osmo_strlcpy(buf, epstart, buf_len);
+	return 0;
+}
+
 /* We received an IPA-encapsulated MGCP message from a MSC. Transfers msg ownership. */
 int bsc_sccplite_rx_mgcp(struct osmo_ss7_asp *asp, struct msgb *msg)
 {
 	struct bsc_msc_data *msc;
+	struct gsm_subscriber_connection *conn;
+	char rcv_ep_local_name[1024];
+	struct osmo_sockaddr_str osa_str = {};
+	struct osmo_sockaddr osa = {};
+	socklen_t dest_len;
+	struct mgcp_client *mgcp_cli = NULL;
 	int rc;
 
-	LOGP(DMSC, LOGL_NOTICE, "%s: Received IPA-encapsulated MGCP: %s\n", asp->cfg.name, msg->l2h);
+	LOGP(DMSC, LOGL_INFO, "%s: Received IPA-encapsulated MGCP: %s\n",
+	     osmo_ss7_asp_get_name(asp), msg->l2h);
+
 	msc = msc_from_asp(asp);
-	if (msc) {
-		/* we don't have a write queue here as we simply expect the socket buffers
-		 * to be large enough to deal with whatever small/infrequent MGCP messages */
-		rc = send(msc->mgcp_ipa.ofd.fd, msgb_l2(msg), msgb_l2len(msg), 0);
-	} else
+	if (!msc) {
 		rc = 0;
+		goto free_msg_ret;
+	}
+
+	rc = parse_local_endpoint_name(rcv_ep_local_name, sizeof(rcv_ep_local_name), (const char *)msg->l2h);
+	if (rc < 0) {
+		LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse CIC\n",
+		     osmo_ss7_asp_get_name(asp));
+		goto free_msg_ret;
+	}
+
+	/* Lookup which conn attached to the MSC holds an MGW endpoint with the
+	 * name Endpoint Number as the one provided in the MGCP msg we received
+	 * from MSC. Since CIC are unique per MSC, that's the same MGW in the
+	 * pool where we have to forward the MGCP message. */
+	llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {
+		const char *ep_local_name;
+		if (conn->sccp.msc != msc)
+			continue; /* Only conns belonging to this MSC */
+		if (!conn->user_plane.mgw_endpoint)
+			continue;
+		ep_local_name = osmo_mgcpc_ep_local_name(conn->user_plane.mgw_endpoint);
+		LOGPFSMSL(conn->fi, DMSC, LOGL_DEBUG, "ep_local_name='%s' vs rcv_ep_local_name='%s'\n",
+			  ep_local_name ? : "(null)", rcv_ep_local_name);
+		if (!ep_local_name)
+			continue;
+		if (strcmp(ep_local_name, rcv_ep_local_name) != 0)
+			continue;
+		mgcp_cli = osmo_mgcpc_ep_client(conn->user_plane.mgw_endpoint);
+		if (!mgcp_cli)
+			continue;
+		break;
+	}
+
+	if (!mgcp_cli) {
+		LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to find associated MGW\n",
+		     osmo_ss7_asp_get_name(asp));
+		rc = 0;
+		goto free_msg_ret;
+	}
+
+	rc = osmo_sockaddr_str_from_str(&osa_str, mgcp_client_remote_addr_str(mgcp_cli),
+					mgcp_client_remote_port(mgcp_cli));
+	if (rc < 0) {
+		LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse MGCP address %s:%u\n",
+		     osmo_ss7_asp_get_name(asp), mgcp_client_remote_addr_str(mgcp_cli), mgcp_client_remote_port(mgcp_cli));
+		goto free_msg_ret;
+	}
+
+	LOGP(DMSC, LOGL_NOTICE, "%s: Forwarding IPA-encapsulated MGCP to MGW at " OSMO_SOCKADDR_STR_FMT "\n",
+	     osmo_ss7_asp_get_name(asp), OSMO_SOCKADDR_STR_FMT_ARGS_NOT_NULL(&osa_str));
+
+	rc = osmo_sockaddr_str_to_sockaddr(&osa_str, &osa.u.sas);
+	if (rc < 0) {
+		LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse MGCP address " OSMO_SOCKADDR_STR_FMT "\n",
+		     osmo_ss7_asp_get_name(asp), OSMO_SOCKADDR_STR_FMT_ARGS_NOT_NULL(&osa_str));
+		goto free_msg_ret;
+	}
+	dest_len = osmo_sockaddr_size(&osa);
+
+	/* we don't have a write queue here as we simply expect the socket buffers
+	 * to be large enough to deal with whatever small/infrequent MGCP messages */
+	rc = sendto(msc->mgcp_ipa.ofd.fd, msgb_l2(msg), msgb_l2len(msg), 0, &osa.u.sa, dest_len);
 
+free_msg_ret:
 	msgb_free(msg);
 	return rc;
 }
@@ -71,7 +184,7 @@ int bsc_sccplite_mgcp_proxy_cb(struct osmo_fd *ofd, unsigned int what)
 	struct msgb *msg;
 	int rc;
 
-	if (!(what & BSC_FD_READ))
+	if (!(what & OSMO_FD_READ))
 		return 0;
 
 	msg = msgb_alloc_headroom(1024, 16, "MGCP->IPA");