Change in osmo-bsc-nat[master]: Support forwarding messages with multiple BSCs

23 Mar 2022

osmith has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bsc-nat/+/27476 )
Change subject: Support forwarding messages with multiple BSCs
......................................................................
Support forwarding messages with multiple BSCs
Implement a proper subscriber connection mapping. Create a new
subscr_conn when one of the stored BSCs sends a conn.ind and use that
subscr_conn for all related connection-oriented messages with the same
RAN-side conn_id to send messages back and forth between BSC and MSC.
Add subscr_conn_get_next_id based on OsmoBSC's
bsc_sccp_inst_next_conn_id.
With this patch, it's possible to do a successful Location Updating
procedure between MS2 and MSC in the following network:
MS1 --- BTS1 --- BSC1 --.
                          BSCNAT --- MSC
  MS2 --- BTS2 --- BSC2 --'
Related: SYS#5560
Change-Id: I1556aa665fbb0a97507f98794e74820731fa6935
---
M doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg
M include/osmocom/bsc_nat/Makefile.am
M include/osmocom/bsc_nat/bsc.h
M include/osmocom/bsc_nat/bsc_nat.h
M include/osmocom/bsc_nat/msc.h
A include/osmocom/bsc_nat/subscr_conn.h
M src/osmo-bsc-nat/Makefile.am
M src/osmo-bsc-nat/bsc.c
M src/osmo-bsc-nat/bsc_nat.c
M src/osmo-bsc-nat/bsc_nat_fsm.c
M src/osmo-bsc-nat/msc.c
A src/osmo-bsc-nat/subscr_conn.c
12 files changed, 258 insertions(+), 85 deletions(-)
Approvals:
  Jenkins Builder: Verified
  pespin: Looks good to me, but someone else must approve
  laforge: Looks good to me, but someone else must approve
  osmith: Looks good to me, approved

diff --git a/doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg b/doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg
index f56dcb0..2f5ff39 100644
--- a/doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg
+++ b/doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg
@@ -13,10 +13,6 @@
  asp asp-clnt-OsmoBSCNAT-RAN 2905 0 m3ua
   remote-ip 127.0.0.2
   local-ip 127.0.0.4
- sccp-address bsc
-  routing-indicator PC
-  point-code 0.23.3
-  subsystem-number 254
bsc-nat
  cs7-instance-cn 0
diff --git a/include/osmocom/bsc_nat/Makefile.am b/include/osmocom/bsc_nat/Makefile.am
index 1c675f7..81dacad 100644
--- a/include/osmocom/bsc_nat/Makefile.am
+++ b/include/osmocom/bsc_nat/Makefile.am
@@ -5,5 +5,6 @@
    bssap.h \
    logging.h \
    msc.h \
+	subscr_conn.h \
    vty.h \
    $(NULL)
diff --git a/include/osmocom/bsc_nat/bsc.h b/include/osmocom/bsc_nat/bsc.h
index 34590b9..7c11a82 100644
--- a/include/osmocom/bsc_nat/bsc.h
+++ b/include/osmocom/bsc_nat/bsc.h
@@ -29,3 +29,4 @@
 struct bsc *bsc_alloc(struct osmo_sccp_addr *addr);
 struct bsc *bsc_get_by_pc(uint32_t pointcode);
 void bsc_free(struct bsc *bsc);
+void bsc_free_subscr_conn_all(struct bsc *bsc);
diff --git a/include/osmocom/bsc_nat/bsc_nat.h b/include/osmocom/bsc_nat/bsc_nat.h
index 9e58a79..93717cc 100644
--- a/include/osmocom/bsc_nat/bsc_nat.h
+++ b/include/osmocom/bsc_nat/bsc_nat.h
@@ -37,14 +37,17 @@
struct bsc_nat {
    struct osmo_fsm_inst *fi;
+	struct llist_head subscr_conns; /* list of struct subscr_conn */
struct {
    	struct bsc_nat_sccp_inst *sccp_inst;
+		uint32_t subscr_conn_id_next;
    	struct llist_head mscs; /* list of struct msc */
    } cn;
struct {
    	struct bsc_nat_sccp_inst *sccp_inst;
+		uint32_t subscr_conn_id_next;
    	struct llist_head bscs; /* list of struct bsc */
    } ran;
 };
diff --git a/include/osmocom/bsc_nat/msc.h b/include/osmocom/bsc_nat/msc.h
index db42526..77fc001 100644
--- a/include/osmocom/bsc_nat/msc.h
+++ b/include/osmocom/bsc_nat/msc.h
@@ -39,3 +39,4 @@
 bool msc_is_connected(struct msc *msc);
void msc_free(struct msc *msc);
+void msc_free_subscr_conn_all(struct msc *msc);
diff --git a/include/osmocom/bsc_nat/subscr_conn.h b/include/osmocom/bsc_nat/subscr_conn.h
new file mode 100644
index 0000000..696e0c3
--- /dev/null
+++ b/include/osmocom/bsc_nat/subscr_conn.h
@@ -0,0 +1,43 @@
+/* (C) 2021 by sysmocom - s.f.m.c. GmbH info@sysmocom.de
+ * Author: Oliver Smith osmith@sysmocom.de
+ * 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/lienses/.
+ *
+ */
+
+#pragma once
+
+/* connection for one subscriber */
+struct subscr_conn {
+	struct llist_head list;
+
+	struct {
+		uint32_t id;
+		struct msc *msc;
+	} cn;
+
+	struct {
+		uint32_t id;
+		struct bsc *bsc;
+	} ran;
+};
+
+int subscr_conn_get_next_id(enum bsc_nat_net net);
+
+struct subscr_conn *subscr_conn_alloc(struct msc *msc, struct bsc *bsc, uint32_t id_cn, uint32_t id_ran);
+
+struct subscr_conn *subscr_conn_get_by_id(uint32_t id, enum bsc_nat_net net);
+
+void subscr_conn_free(struct subscr_conn *subscr_conn);
diff --git a/src/osmo-bsc-nat/Makefile.am b/src/osmo-bsc-nat/Makefile.am
index 8fd5667..e2b11ca 100644
--- a/src/osmo-bsc-nat/Makefile.am
+++ b/src/osmo-bsc-nat/Makefile.am
@@ -33,6 +33,7 @@
    main.c \
    msc.c \
    msc_fsm.c \
+	subscr_conn.c \
    vty.c \
    $(NULL)
diff --git a/src/osmo-bsc-nat/bsc.c b/src/osmo-bsc-nat/bsc.c
index 2ad6e0e..0461909 100644
--- a/src/osmo-bsc-nat/bsc.c
+++ b/src/osmo-bsc-nat/bsc.c
@@ -21,6 +21,7 @@
 #include <osmocom/bsc_nat/bsc.h>
 #include <osmocom/bsc_nat/bsc_nat.h>
 #include <osmocom/bsc_nat/logging.h>
+#include <osmocom/bsc_nat/subscr_conn.h>
struct bsc *bsc_alloc(struct osmo_sccp_addr *addr)
 {
@@ -51,9 +52,20 @@
    return NULL;
 }
+void bsc_free_subscr_conn_all(struct bsc *bsc)
+{
+	struct subscr_conn *subscr_conn;
+
+	llist_for_each_entry(subscr_conn, &g_bsc_nat->subscr_conns, list) {
+		if (subscr_conn->ran.bsc == bsc)
+			subscr_conn_free(subscr_conn);
+	}
+}
+
 void bsc_free(struct bsc *bsc)
 {
    LOGP(DMAIN, LOGL_DEBUG, "Del %s\n", talloc_get_name(bsc));
+	bsc_free_subscr_conn_all(bsc);
    llist_del(&bsc->list);
    talloc_free(bsc);
 }
diff --git a/src/osmo-bsc-nat/bsc_nat.c b/src/osmo-bsc-nat/bsc_nat.c
index 23d7498..7ba24e6 100644
--- a/src/osmo-bsc-nat/bsc_nat.c
+++ b/src/osmo-bsc-nat/bsc_nat.c
@@ -18,6 +18,7 @@
  */
#include "config.h"
+#include <inttypes.h>
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/utils.h>
 #include <osmocom/bsc_nat/bsc.h>
@@ -25,6 +26,7 @@
 #include <osmocom/bsc_nat/bsc_nat_fsm.h>
 #include <osmocom/bsc_nat/logging.h>
 #include <osmocom/bsc_nat/msc.h>
+#include <osmocom/bsc_nat/subscr_conn.h>
struct bsc_nat *bsc_nat_alloc(void *tall_ctx)
 {
@@ -41,6 +43,7 @@
    OSMO_ASSERT(bsc_nat->ran.sccp_inst);
    talloc_set_name_const(bsc_nat->ran.sccp_inst, "struct bsc_nat_sccp_inst (RAN)");
+	INIT_LLIST_HEAD(&bsc_nat->subscr_conns);
    INIT_LLIST_HEAD(&bsc_nat->cn.mscs);
    INIT_LLIST_HEAD(&bsc_nat->ran.bscs);
@@ -51,6 +54,7 @@
void bsc_nat_free(struct bsc_nat *bsc_nat)
 {
+	struct subscr_conn *subscr_conn, *s;
    struct msc *msc, *m;
    struct bsc *bsc, *b;
@@ -59,6 +63,10 @@
    	bsc_nat->fi = NULL;
    }
+	llist_for_each_entry_safe(subscr_conn, s, &bsc_nat->subscr_conns, list) {
+		subscr_conn_free(subscr_conn);
+	}
+
    llist_for_each_entry_safe(msc, m, &bsc_nat->cn.mscs, list) {
    	msc_free(msc);
    }
diff --git a/src/osmo-bsc-nat/bsc_nat_fsm.c b/src/osmo-bsc-nat/bsc_nat_fsm.c
index ad10ea2..090c38f 100644
--- a/src/osmo-bsc-nat/bsc_nat_fsm.c
+++ b/src/osmo-bsc-nat/bsc_nat_fsm.c
@@ -19,17 +19,20 @@
#include "config.h"
 #include <errno.h>
+#include <inttypes.h>
 #include <stdint.h>
 #include <osmocom/core/fsm.h>
 #include <osmocom/core/select.h>
 #include <osmocom/gsm/gsm0808.h>
 #include <osmocom/sigtran/osmo_ss7.h>
 #include <osmocom/sigtran/sccp_helpers.h>
+#include <osmocom/bsc_nat/bsc.h>
 #include <osmocom/bsc_nat/bsc_nat.h>
 #include <osmocom/bsc_nat/bsc_nat_fsm.h>
 #include <osmocom/bsc_nat/bssap.h>
 #include <osmocom/bsc_nat/logging.h>
 #include <osmocom/bsc_nat/msc.h>
+#include <osmocom/bsc_nat/subscr_conn.h>
#define DEFAULT_PC_RAN "0.23.1" /* same as default for OsmoMSC */
 #define DEFAULT_PC_CN "0.23.3" /* same as default for OsmoBSC */
@@ -47,13 +50,6 @@
    BSC_NAT_FSM_EV_STOP,
 };
-static struct bsc_nat_sccp_inst *sccp_inst_dest(struct bsc_nat_sccp_inst *src)
-{
-	if (src == g_bsc_nat->cn.sccp_inst)
-		return g_bsc_nat->ran.sccp_inst;
-	return g_bsc_nat->cn.sccp_inst;
-}
-
 /* For connection-oriented messages, figure out which side is not the BSCNAT,
  * either the called_addr or calling_addr. */
 static int sccp_sap_get_peer_addr_in(struct bsc_nat_sccp_inst *src, struct osmo_sccp_addr **peer_addr_in,
@@ -79,37 +75,13 @@
    return -1;
 }
-/* Figure out who will receive the message.
- * For now this is simplified by assuming there is only one MSC, one BSC. */
-static int sccp_sap_get_peer_addr_out(struct bsc_nat_sccp_inst *src, struct osmo_sccp_addr *peer_addr_in,
-				      struct osmo_sccp_addr *peer_addr_out)
-{
-	struct bsc_nat_sccp_inst *dest = sccp_inst_dest(src);
-
-	if (src == g_bsc_nat->ran.sccp_inst) {
-		if (osmo_sccp_addr_by_name_local(peer_addr_out, "msc", dest->ss7_inst) < 0) {
-			LOGP(DMAIN, LOGL_ERROR, "Could not find MSC in address book\n");
-			return -1;
-		}
-	} else {
-		if (osmo_sccp_addr_by_name_local(peer_addr_out, "bsc", dest->ss7_inst) < 0) {
-			LOGP(DMAIN, LOGL_ERROR, "Could not find BSC in address book\n");
-			return -2;
-		}
-	}
-
-	return 0;
-}
-
-/* Handle incoming messages from CN (MSC). For now this is simplified by
- * assuming there is only one MSC, one BSC (not yet translating connection ids
- * etc.). */
+/* Handle incoming messages from CN (MSC) */
 static int sccp_sap_up_cn(struct osmo_prim_hdr *oph, void *scu)
 {
    struct bsc_nat_sccp_inst *sccp_inst = osmo_sccp_user_get_priv(scu);
    struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
    struct osmo_sccp_addr *addr; /* MSC's address */
-	struct osmo_sccp_addr peer_addr_out;
+	struct subscr_conn *subscr_conn;
    int rc = -1;
LOGP(DMAIN, LOGL_DEBUG, "Rx %s from CN\n", osmo_scu_prim_name(oph));
@@ -117,23 +89,9 @@
    switch (OSMO_PRIM_HDR(oph)) {
    case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
    	/* indication of new inbound connection request */
-		if (sccp_sap_get_peer_addr_in(sccp_inst, &addr, &prim->u.connect.called_addr,
-					      &prim->u.connect.calling_addr) < 0)
-			goto error;
-
-		if (sccp_sap_get_peer_addr_out(sccp_inst, addr, &peer_addr_out) < 0)
-			goto error;
-
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_ran(&peer_addr_out));
-
-		msgb_pull_to_l2(oph->msg);
-		osmo_sccp_tx_conn_req(g_bsc_nat->ran.sccp_inst->scu,
-				      prim->u.connect.conn_id,
-				      &g_bsc_nat->ran.sccp_inst->addr,
-				      &peer_addr_out,
-				      oph->msg->data,
-				      msgb_length(oph->msg));
-		rc = 0;
+		/* FIXME: MSC has sent a message without conn_id, figure out to
+		 * which BSC to forward this. */
+		LOGP(DMAIN, LOGL_ERROR, "%s(%s) is not implemented!\n", __func__, osmo_scu_prim_name(oph));
    	break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_CONFIRM):
@@ -142,15 +100,19 @@
    				      &prim->u.connect.calling_addr) < 0)
    		goto error;
-		if (sccp_sap_get_peer_addr_out(sccp_inst, addr, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.connect.conn_id, BSC_NAT_NET_CN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.connect.conn_id,
+			     bsc_nat_print_addr_cn(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_ran(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
msgb_pull_to_l2(oph->msg);
    	osmo_sccp_tx_conn_resp(g_bsc_nat->ran.sccp_inst->scu,
-				       prim->u.connect.conn_id,
-				       &peer_addr_out,
+				       subscr_conn->ran.id,
+				       &subscr_conn->ran.bsc->addr,
    			       oph->msg->data,
    			       msgb_length(oph->msg));
    	rc = 0;
@@ -158,14 +120,18 @@
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
    	/* connection-oriented data received */
-		if (sccp_sap_get_peer_addr_out(sccp_inst, NULL, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.data.conn_id, BSC_NAT_NET_CN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.data.conn_id,
+			     bsc_nat_print_addr_cn(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_ran(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
msgb_pull_to_l2(oph->msg);
    	osmo_sccp_tx_data(g_bsc_nat->ran.sccp_inst->scu,
-				  prim->u.data.conn_id,
+				  subscr_conn->ran.id,
    			  oph->msg->data,
    			  msgb_length(oph->msg));
    	rc = 0;
@@ -173,15 +139,22 @@
case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
    	/* indication of disconnect */
-		if (sccp_sap_get_peer_addr_out(sccp_inst, NULL, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.disconnect.conn_id, BSC_NAT_NET_CN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.disconnect.conn_id,
+			     bsc_nat_print_addr_cn(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_ran(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
osmo_sccp_tx_disconn(g_bsc_nat->ran.sccp_inst->scu,
-				     prim->u.disconnect.conn_id,
-				     &prim->u.disconnect.responding_addr,
+				     subscr_conn->ran.id,
+				     &g_bsc_nat->ran.sccp_inst->addr,
    			     prim->u.disconnect.cause);
+
+		subscr_conn_free(subscr_conn);
+
    	rc = 0;
    	break;
@@ -200,16 +173,15 @@
    return rc;
 }
-/* Handle incoming messages from RAN (BSC). For now this is simplified by
- * assuming there is only one MSC, one BSC (not yet translating connection ids
- * etc.). */
+/* Handle incoming messages from RAN (BSC) */
 static int sccp_sap_up_ran(struct osmo_prim_hdr *oph, void *scu)
 {
    struct bsc_nat_sccp_inst *sccp_inst = osmo_sccp_user_get_priv(scu);
    struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
    struct osmo_sccp_addr *addr; /* BSC's address */
-	struct osmo_sccp_addr peer_addr_out;
+	struct subscr_conn *subscr_conn;
    struct msc *msc;
+	struct bsc *bsc;
    int rc = -1;
LOGP(DMAIN, LOGL_DEBUG, "Rx %s from RAN\n", osmo_scu_prim_name(oph));
@@ -227,16 +199,25 @@
    				      &prim->u.connect.calling_addr) < 0)
    		goto error;
-		if (sccp_sap_get_peer_addr_out(sccp_inst, addr, &peer_addr_out) < 0)
-			goto error;
+		bsc = bsc_get_by_pc(addr->pc);
+		if (!bsc)
+			bsc = bsc_alloc(addr);
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_cn(&peer_addr_out));
+		if (subscr_conn_get_by_id(prim->u.connect.conn_id, BSC_NAT_NET_RAN)) {
+			LOGP(DMAIN, LOGL_ERROR, "%s attempted to create new connection with already used"
+				 " conn_id=%" PRIu32 ", ignoring\n", talloc_get_name(bsc), prim->u.connect.conn_id);
+			goto error;
+		}
+
+		subscr_conn = subscr_conn_alloc(msc, bsc, subscr_conn_get_next_id(BSC_NAT_NET_CN), prim->u.connect.conn_id);
+
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
msgb_pull_to_l2(oph->msg);
    	osmo_sccp_tx_conn_req(g_bsc_nat->cn.sccp_inst->scu,
-				      prim->u.connect.conn_id,
+				      subscr_conn->cn.id,
    			      &g_bsc_nat->cn.sccp_inst->addr,
-				      &peer_addr_out,
+				      &subscr_conn->cn.msc->addr,
    			      oph->msg->data,
    			      msgb_length(oph->msg));
    	rc = 0;
@@ -248,15 +229,19 @@
    				      &prim->u.connect.calling_addr) < 0)
    		goto error;
-		if (sccp_sap_get_peer_addr_out(sccp_inst, addr, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.connect.conn_id, BSC_NAT_NET_RAN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.connect.conn_id,
+			     bsc_nat_print_addr_ran(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_cn(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
msgb_pull_to_l2(oph->msg);
    	osmo_sccp_tx_conn_resp(g_bsc_nat->cn.sccp_inst->scu,
-				       prim->u.connect.conn_id,
-				       &peer_addr_out,
+				       subscr_conn->cn.id,
+				       &subscr_conn->cn.msc->addr,
    			       oph->msg->data,
    			       msgb_length(oph->msg));
    	rc = 0;
@@ -264,14 +249,18 @@
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
    	/* connection-oriented data received */
-		if (sccp_sap_get_peer_addr_out(sccp_inst, NULL, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.data.conn_id, BSC_NAT_NET_RAN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.data.conn_id,
+			     bsc_nat_print_addr_ran(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_cn(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
msgb_pull_to_l2(oph->msg);
    	osmo_sccp_tx_data(g_bsc_nat->cn.sccp_inst->scu,
-				  prim->u.data.conn_id,
+				  subscr_conn->cn.id,
    			  oph->msg->data,
    			  msgb_length(oph->msg));
    	rc = 0;
@@ -279,15 +268,22 @@
case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
    	/* indication of disconnect */
-		if (sccp_sap_get_peer_addr_out(sccp_inst, NULL, &peer_addr_out) < 0)
+		subscr_conn = subscr_conn_get_by_id(prim->u.disconnect.conn_id, BSC_NAT_NET_RAN);
+		if (!subscr_conn) {
+			LOGP(DMAIN, LOGL_ERROR, "Unknown conn_id=%" PRIu32 " from %s\n", prim->u.disconnect.conn_id,
+			     bsc_nat_print_addr_ran(addr));
    		goto error;
+		}
-		LOGP(DMAIN, LOGL_DEBUG, "Fwd to %s\n", bsc_nat_print_addr_cn(&peer_addr_out));
+		LOGP(DMAIN, LOGL_DEBUG, "Fwd via %s\n", talloc_get_name(subscr_conn));
osmo_sccp_tx_disconn(g_bsc_nat->cn.sccp_inst->scu,
-				     prim->u.disconnect.conn_id,
-				     &prim->u.disconnect.responding_addr,
+				     subscr_conn->cn.id,
+				     &g_bsc_nat->cn.sccp_inst->addr,
    			     prim->u.disconnect.cause);
+
+		subscr_conn_free(subscr_conn);
+
    	rc = 0;
    	break;
diff --git a/src/osmo-bsc-nat/msc.c b/src/osmo-bsc-nat/msc.c
index e78a8e6..4204bac 100644
--- a/src/osmo-bsc-nat/msc.c
+++ b/src/osmo-bsc-nat/msc.c
@@ -22,6 +22,7 @@
 #include <osmocom/bsc_nat/msc.h>
 #include <osmocom/bsc_nat/bsc_nat.h>
 #include <osmocom/bsc_nat/logging.h>
+#include <osmocom/bsc_nat/subscr_conn.h>
extern struct osmo_fsm msc_fsm;
@@ -70,9 +71,20 @@
    return llist_first_entry(&g_bsc_nat->cn.mscs, struct msc, list);
 }
+void msc_free_subscr_conn_all(struct msc *msc)
+{
+	struct subscr_conn *subscr_conn;
+
+	llist_for_each_entry(subscr_conn, &g_bsc_nat->subscr_conns, list) {
+		if (subscr_conn->cn.msc == msc)
+			subscr_conn_free(subscr_conn);
+	}
+}
+
 void msc_free(struct msc *msc)
 {
    LOGP(DMAIN, LOGL_DEBUG, "Del %s\n", talloc_get_name(msc));
+	msc_free_subscr_conn_all(msc);
    llist_del(&msc->list);
    osmo_fsm_inst_free(msc->fi);
    talloc_free(msc);
diff --git a/src/osmo-bsc-nat/subscr_conn.c b/src/osmo-bsc-nat/subscr_conn.c
new file mode 100644
index 0000000..02afb7d
--- /dev/null
+++ b/src/osmo-bsc-nat/subscr_conn.c
@@ -0,0 +1,99 @@
+/* (C) 2022 by sysmocom - s.f.m.c. GmbH info@sysmocom.de
+ * Author: Oliver Smith osmith@sysmocom.de
+ * 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/lienses/.
+ *
+ */
+
+#include "config.h"
+#include <inttypes.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/bsc_nat/bsc.h>
+#include <osmocom/bsc_nat/bsc_nat.h>
+#include <osmocom/bsc_nat/msc.h>
+#include <osmocom/bsc_nat/subscr_conn.h>
+#include <osmocom/bsc_nat/logging.h>
+
+/* Get the next available id in either CN or RAN. */
+int subscr_conn_get_next_id(enum bsc_nat_net net)
+{
+	uint32_t *id;
+
+	if (net == BSC_NAT_NET_RAN)
+		id = &g_bsc_nat->ran.subscr_conn_id_next;
+	else
+		id = &g_bsc_nat->cn.subscr_conn_id_next;
+
+	for (int i = 0; i < 0xFFFFFF; i++) {
+		struct subscr_conn *subscr_conn;
+		bool already_used = false;
+
+		*id = (*id + 1) & 0xffffff;
+
+		llist_for_each_entry(subscr_conn, &g_bsc_nat->subscr_conns, list) {
+			if ((net == BSC_NAT_NET_RAN && subscr_conn->ran.id == *id)
+			    || (net == BSC_NAT_NET_CN && subscr_conn->cn.id == *id)) {
+				already_used = true;
+				break;
+			}
+		}
+
+		if (!already_used)
+			return *id;
+	}
+	return -1;
+}
+
+struct subscr_conn *subscr_conn_alloc(struct msc *msc, struct bsc *bsc, uint32_t id_cn, uint32_t id_ran)
+{
+	struct subscr_conn *subscr_conn = talloc_zero(g_bsc_nat, struct subscr_conn);
+
+	OSMO_ASSERT(subscr_conn);
+	talloc_set_name(subscr_conn, "SUBSCR-CONN %s:%" PRIu32 " <=> %s:%" PRIu32,
+			talloc_get_name(msc), id_cn,
+			talloc_get_name(bsc), id_ran);
+
+	LOGP(DMAIN, LOGL_DEBUG, "Add %s\n", talloc_get_name(subscr_conn));
+
+	subscr_conn->cn.id = id_cn;
+	subscr_conn->cn.msc = msc;
+	subscr_conn->ran.id = id_ran;
+	subscr_conn->ran.bsc = bsc;
+
+	INIT_LLIST_HEAD(&subscr_conn->list);
+	llist_add(&subscr_conn->list, &g_bsc_nat->subscr_conns);
+
+	return subscr_conn;
+}
+
+struct subscr_conn *subscr_conn_get_by_id(uint32_t id, enum bsc_nat_net net)
+{
+	struct subscr_conn *subscr_conn;
+
+	llist_for_each_entry(subscr_conn, &g_bsc_nat->subscr_conns, list) {
+		if ((net == BSC_NAT_NET_RAN && subscr_conn->ran.id == id)
+		    || (net == BSC_NAT_NET_CN && subscr_conn->cn.id == id))
+			return subscr_conn;
+	}
+
+	return NULL;
+}
+
+void subscr_conn_free(struct subscr_conn *subscr_conn)
+{
+	LOGP(DMAIN, LOGL_DEBUG, "Del %s\n", talloc_get_name(subscr_conn));
+	llist_del(&subscr_conn->list);
+	talloc_free(subscr_conn);
+}
-- 
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Gerrit-Project: osmo-bsc-nat
Gerrit-Branch: master
Gerrit-Change-Id: I1556aa665fbb0a97507f98794e74820731fa6935
Gerrit-Change-Number: 27476
Gerrit-PatchSet: 4
Gerrit-Owner: osmith osmith@sysmocom.de
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge laforge@osmocom.org
Gerrit-Reviewer: osmith osmith@sysmocom.de
Gerrit-Reviewer: pespin pespin@sysmocom.de
Gerrit-MessageType: merged



    

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Change in osmo-bsc-nat[master]: Support forwarding messages with multiple BSCs