1 files changed, 91 insertions, 0 deletions
diff --git a/src/osmo-bsc/osmo_bsc_mgcp.c b/src/osmo-bsc/osmo_bsc_mgcp.c
new file mode 100644
index 000000000..d984125ab
--- /dev/null
+++ b/src/osmo-bsc/osmo_bsc_mgcp.c
@@ -0,0 +1,91 @@
+/*
+ * SCCPlite MGCP handling
+ *
+ * (C) 2018 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <osmocom/bsc/bsc_msc_data.h>
+#include <osmocom/bsc/osmo_bsc.h>
+#include <osmocom/bsc/gsm_data.h>
+#include <osmocom/bsc/debug.h>
+#include <osmocom/gsm/ipa.h>
+#include <osmocom/gsm/protocol/ipaccess.h>
+#include <osmocom/bsc/osmo_bsc_sigtran.h>
+
+#include <arpa/inet.h>
+
+/* Determine MSC based on the ASP over which the message was received */
+static struct bsc_msc_data *msc_from_asp(struct osmo_ss7_asp *asp)
+{
+	int msc_nr;
+	/* 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);
+		return NULL;
+	}
+	return osmo_msc_data_find(bsc_gsmnet, msc_nr);
+}
+
+/* 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;
+	int rc;
+
+	LOGP(DMSC, LOGL_NOTICE, "%s: Received IPA-encapsulated MGCP: %s\n", asp->cfg.name, 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 enouhg to deal with whatever small/infrequent MGCP messages */
+		rc = send(msc->mgcp_ipa.ofd.fd, msgb_l2(msg), msgb_l2len(msg), 0);
+	} else
+		rc = 0;
+
+	msgb_free(msg);
+	return rc;
+}
+
+/* we received some data on the UDP proxy socket from the MGW. Pass it to MSC via IPA */
+int bsc_sccplite_mgcp_proxy_cb(struct osmo_fd *ofd, unsigned int what)
+{
+	struct bsc_msc_data *msc = ofd->data;
+	struct msgb *msg;
+	int rc;
+
+	if (!(what & BSC_FD_READ))
+		return 0;
+
+	msg = msgb_alloc_headroom(1024, 16, "MGCP->IPA");
+	OSMO_ASSERT(msg);
+	rc = recv(ofd->fd, msg->data, msgb_tailroom(msg), 0);
+	if (rc <= 0) {
+		LOGP(DMSC, LOGL_ERROR, "error receiving data from MGCP<-> IPA proxy UDP socket: "
+			"%s\n", strerror(errno));
+		msgb_free(msg);
+		return rc;
+	}
+	msg->l2h = msgb_put(msg, rc);
+	LOGP(DMSC, LOGL_NOTICE, "Received MGCP on UDP proxy socket: %s\n", msg->l2h);
+
+	ipa_prepend_header(msg, IPAC_PROTO_MGCP_OLD);
+	return bsc_sccplite_msc_send(msc, msg);
+}