[nat] Lookup by BSC Connection otherwise the point of reassigning the is defeated

When sending a MSG to the MSC try to find the to be used "src" reference
by comparing the reference on the BSC and the BSC connection. Only this
tuple needs to be unique.
Actually only when looking at the SRC REF we need to compare the BSC as the
dest reference should be unique but we are just making the check a bit stronger
to make it look symmetric.

4 files changed, 14 insertions, 11 deletions

diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index 64c6b8656..040d39374 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -248,7 +248,7 @@ int create_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc
 int update_sccp_src_ref(struct sccp_connections *sccp, struct bsc_nat_parsed *parsed);
 void remove_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed);
 struct sccp_connections *patch_sccp_src_ref_to_bsc(struct msgb *, struct bsc_nat_parsed *, struct bsc_nat *);
-struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *, struct bsc_nat_parsed *, struct bsc_nat *);
+struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *, struct bsc_nat_parsed *, struct bsc_connection *);
 
 /**
  * MGCP/Audio handling
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index 00dcc8884..eaa9d30bc 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -524,17 +524,17 @@ static int forward_sccp_to_msc(struct bsc_connection *bsc, struct msgb *msg)
 		case SCCP_MSG_TYPE_CR:
 			if (create_sccp_src_ref(bsc, msg, parsed) != 0)
 				goto exit2;
-			con = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+			con = patch_sccp_src_ref_to_msc(msg, parsed, bsc);
 			break;
 		case SCCP_MSG_TYPE_RLSD:
 		case SCCP_MSG_TYPE_CREF:
 		case SCCP_MSG_TYPE_DT1:
 		case SCCP_MSG_TYPE_CC:
 		case SCCP_MSG_TYPE_IT:
-			con = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+			con = patch_sccp_src_ref_to_msc(msg, parsed, bsc);
 			break;
 		case SCCP_MSG_TYPE_RLC:
-			con = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+			con = patch_sccp_src_ref_to_msc(msg, parsed, bsc);
 			remove_sccp_src_ref(bsc, msg, parsed);
 			break;
 		case SCCP_MSG_TYPE_UDT:
diff --git a/openbsc/src/nat/bsc_sccp.c b/openbsc/src/nat/bsc_sccp.c
index e84ffe9c1..58302cc64 100644
--- a/openbsc/src/nat/bsc_sccp.c
+++ b/openbsc/src/nat/bsc_sccp.c
@@ -204,11 +204,14 @@ struct sccp_connections *patch_sccp_src_ref_to_bsc(struct msgb *msg,
  */
 struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *msg,
 						   struct bsc_nat_parsed *parsed,
-						   struct bsc_nat *nat)
+						   struct bsc_connection *bsc)
 {
 	struct sccp_connections *conn;
 
-	llist_for_each_entry(conn, &nat->sccp_connections, list_entry) {
+	llist_for_each_entry(conn, &bsc->nat->sccp_connections, list_entry) {
+		if (conn->bsc != bsc)
+			continue;
+
 		if (parsed->src_local_ref) {
 			if (equal(parsed->src_local_ref, &conn->real_ref)) {
 				*parsed->src_local_ref = conn->patched_ref;
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 7ff2c200f..e046e776e 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -267,7 +267,7 @@ static void test_contrack()
 	/* 1.) create a connection */
 	copy_to_msg(msg, bsc_cr, sizeof(bsc_cr));
 	parsed = bsc_nat_parse(msg);
-	con_found = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+	con_found = patch_sccp_src_ref_to_msc(msg, parsed, con);
 	if (con_found != NULL) {
 		fprintf(stderr, "Con should not exist %p\n", con_found);
 		abort();
@@ -277,7 +277,7 @@ static void test_contrack()
 		fprintf(stderr, "Failed to create a ref\n");
 		abort();
 	}
-	con_found = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+	con_found = patch_sccp_src_ref_to_msc(msg, parsed, con);
 	if (!con_found || con_found->bsc != con) {
 		fprintf(stderr, "Failed to find the con: %p\n", con_found);
 		abort();
@@ -301,7 +301,7 @@ static void test_contrack()
 	/* 3.) send some data */
 	copy_to_msg(msg, bsc_dtap, sizeof(bsc_dtap));
 	parsed = bsc_nat_parse(msg);
-	con_found = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+	con_found = patch_sccp_src_ref_to_msc(msg, parsed, con);
 	VERIFY(con_found, con, msg, bsc_dtap_patched, "BSC DTAP");
 
 	/* 4.) receive some data */
@@ -319,7 +319,7 @@ static void test_contrack()
 	/* 6.) confirm the connection close */
 	copy_to_msg(msg, bsc_rlc, sizeof(bsc_rlc));
 	parsed = bsc_nat_parse(msg);
-	con_found = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+	con_found = patch_sccp_src_ref_to_msc(msg, parsed, con);
 	if (!con_found || con_found->bsc != con) {
 		fprintf(stderr, "Failed to find the con: %p\n", con_found);
 		abort();
@@ -333,7 +333,7 @@ static void test_contrack()
 
 	copy_to_msg(msg, bsc_rlc, sizeof(bsc_rlc));
 	parsed = bsc_nat_parse(msg);
-	con_found = patch_sccp_src_ref_to_msc(msg, parsed, nat);
+	con_found = patch_sccp_src_ref_to_msc(msg, parsed, con);
 
 	/* verify that it is gone */
 	if (con_found != NULL) {