gprs: Add GSUP client

This commit adds the client code to get subscriber information from a
remote server. It provides an IPA over TCP connection to transmit and
receive GSUP messages.

Sponsored-by: On-Waves ehf

openbsc/include/openbsc/Makefile.am

@@ -15,7 +15,8 @@ noinst_HEADERS = abis_nm.h abis_rsl.h db.h gsm_04_08.h gsm_data.h \
 		bss.h gsm_data_shared.h ipaccess.h mncc_int.h \
 		arfcn_range_encode.h nat_rewrite_trie.h bsc_nat_callstats.h \
 		osmux.h mgcp_transcode.h rtp.h gprs_utils.h \
-		 gprs_gb_parse.h smpp.h meas_feed.h gprs_gsup_messages.h
+		 gprs_gb_parse.h smpp.h meas_feed.h gprs_gsup_messages.h \
+		 gprs_gsup_client.h
 
 openbsc_HEADERS = gsm_04_08.h meas_rep.h bsc_api.h
 openbscdir = $(includedir)/openbsc

openbsc/include/openbsc/gprs_gsup_client.h

@@ -0,0 +1,44 @@
+/* GPRS Subscriber Update Protocol client */
+
+/* (C) 2014 by Sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Jacob Erlbeck
+ *
+ * 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/>.
+ *
+ */
+#pragma once
+
+struct msgb;
+struct ipa_client_conn;
+struct gprs_gsup_client;
+
+/* Expects message in msg->l2h */
+typedef int (*gprs_gsup_read_cb_t)(struct gprs_gsup_client *gsupc, struct msgb *msg);
+
+struct gprs_gsup_client {
+	struct ipa_client_conn	*link;
+	gprs_gsup_read_cb_t	read_cb;
+	void			*data;
+};
+
+struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
+						 unsigned int tcp_port,
+						 gprs_gsup_read_cb_t read_cb);
+
+void gprs_gsup_client_destroy(struct gprs_gsup_client *gsupc);
+int gprs_gsup_client_send(struct gprs_gsup_client *gsupc, struct msgb *msg);
+struct msgb *gprs_gsup_msgb_alloc(void);
+

openbsc/src/gprs/Makefile.am

@@ -23,7 +23,7 @@ osmo_sgsn_SOURCES =	gprs_gmm.c gprs_sgsn.c gprs_sndcp.c gprs_sndcp_vty.c \
 			sgsn_main.c sgsn_vty.c sgsn_libgtp.c \
 			gprs_llc.c gprs_llc_parse.c gprs_llc_vty.c crc24.c \
 			sgsn_ctrl.c sgsn_auth.c gprs_subscriber.c \
-			gprs_gsup_messages.c gprs_utils.c
+			gprs_gsup_messages.c gprs_utils.c gprs_gsup_client.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
 			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS)

openbsc/src/gprs/gprs_gsup_client.c

@@ -0,0 +1,132 @@
+/* GPRS Subscriber Update Protocol client */
+
+/* (C) 2014 by Sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Jacob Erlbeck
+ *
+ * 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 <openbsc/gprs_gsup_client.h>
+
+#include <osmocom/abis/ipa.h>
+#include <osmocom/gsm/protocol/ipaccess.h>
+#include <osmocom/core/msgb.h>
+
+#include <openbsc/debug.h>
+
+#include <errno.h>
+
+extern void *tall_bsc_ctx;
+
+static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
+{
+	LOGP(DGPRS, LOGL_NOTICE, "GSUP link to %s:%d %s\n",
+		     link->addr, link->port, up ? "UP" : "DOWN");
+
+}
+
+static int gsup_client_read_cb(struct ipa_client_conn *link, struct msgb *msg)
+{
+	struct ipaccess_head *hh = (struct ipaccess_head *) msg->data;
+	struct ipaccess_head_ext *he = (struct ipaccess_head_ext *) msgb_l2(msg);
+	struct gprs_gsup_client *gsupc = (struct gprs_gsup_client *)link->data;
+
+	if (hh->proto != IPAC_PROTO_OSMO)
+		goto invalid;
+
+	if (!he || msgb_l2len(msg) < sizeof(*he) ||
+	    he->proto != IPAC_PROTO_EXT_GSUP)
+		goto invalid;
+
+	msg->l2h = &he->data[0];
+
+	OSMO_ASSERT(gsupc->read_cb != NULL);
+	gsupc->read_cb(gsupc, msg);
+
+	/* Not freeing msg here, because that must be done by the read_cb. */
+	return 0;
+
+invalid:
+	LOGP(DGPRS, LOGL_NOTICE,
+	     "GSUP received an invalid IPA message from %s:%d, size = %d\n",
+	     link->addr, link->port, msgb_length(msg));
+
+	msgb_free(msg);
+	return -1;
+}
+
+struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
+						 unsigned int tcp_port,
+						 gprs_gsup_read_cb_t read_cb)
+{
+	struct gprs_gsup_client *gsupc;
+	int rc;
+
+	gsupc = talloc_zero(tall_bsc_ctx, struct gprs_gsup_client);
+	OSMO_ASSERT(gsupc);
+
+	gsupc->link = ipa_client_conn_create(gsupc,
+					     /* no e1inp */ NULL,
+					     0,
+					     ip_addr, tcp_port,
+					     gsup_client_updown_cb,
+					     gsup_client_read_cb,
+					     /* default write_cb */ NULL,
+					     gsupc);
+	if (!gsupc->link)
+		goto failed;
+
+	rc = ipa_client_conn_open(gsupc->link);
+
+	if (rc < 0 && rc != -EINPROGRESS) {
+		LOGP(DGPRS, LOGL_NOTICE, "GSUP failed to connect to %s:%d\n",
+		     ip_addr, tcp_port);
+		goto failed;
+	}
+
+	gsupc->read_cb = read_cb;
+
+	return gsupc;
+
+failed:
+	talloc_free(gsupc);
+	return NULL;
+}
+
+void gprs_gsup_client_destroy(struct gprs_gsup_client *gsupc)
+{
+	ipa_client_conn_destroy(gsupc->link);
+}
+
+int gprs_gsup_client_send(struct gprs_gsup_client *gsupc, struct msgb *msg)
+{
+	if (!gsupc) {
+		msgb_free(msg);
+		return -ENOTCONN;
+	}
+
+	ipa_prepend_header_ext(msg, IPAC_PROTO_EXT_GSUP);
+	ipa_msg_push_header(msg, IPAC_PROTO_OSMO);
+	ipa_client_conn_send(gsupc->link, msg);
+
+	return 0;
+}
+
+struct msgb *gprs_gsup_msgb_alloc(void)
+{
+	return msgb_alloc_headroom(4000, 64, __func__);
+}