nat: Remember where the BTS is listening for things.
Extract the port from the BSS's MGCP Gateway so we know
where to forward the data to.
diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index 6ec666a..e272349 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -205,5 +205,6 @@
int bsc_mgcp_parse_response(const char *str, int *code, char transaction[60]);
int bsc_mgcp_extract_ci(const char *resp);
+int bsc_mgcp_extract_port(const char *resp);
#endif
diff --git a/openbsc/src/nat/bsc_mgcp_utils.c b/openbsc/src/nat/bsc_mgcp_utils.c
index 74ef67b..82eeefc 100644
--- a/openbsc/src/nat/bsc_mgcp_utils.c
+++ b/openbsc/src/nat/bsc_mgcp_utils.c
@@ -185,7 +185,7 @@
struct msgb *output;
struct bsc_endpoint *bsc_endp = NULL;
struct mgcp_endpoint *endp = NULL;
- int i, code;
+ int i, code, port;
char transaction_id[60];
/* Some assumption that our buffer is big enough.. and null terminate */
@@ -223,6 +223,9 @@
/* make it point to our endpoint */
endp->ci = bsc_mgcp_extract_ci((const char *) msg->l2h);
+ port = bsc_mgcp_extract_port((const char *) msg->l2h);
+ endp->bts_rtp = htons(port);
+ endp->bts_rtcp = htons(port + 1);
output = bsc_mgcp_rewrite((char * ) msg->l2h, msgb_l2len(msg),
bsc->nat->mgcp_cfg->source_addr, endp->rtp_port);
if (!output) {
@@ -254,6 +257,18 @@
return ci;
}
+int bsc_mgcp_extract_port(const char *str)
+{
+ int port;
+ char *res = strstr(str, "m=audio ");
+ if (!res)
+ return 0;
+
+ if (sscanf(res, "m=audio %d RTP/AVP %*d", &port) != 1)
+ return 0;
+ return port;
+}
+
/* we need to replace some strings... */
struct msgb *bsc_mgcp_rewrite(char *input, int length, const char *ip, int port)
{
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index def6bfe..705372c 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -482,6 +482,19 @@
}
}
+static void test_mgcp_parse_port(void)
+{
+ int port;
+
+ fprintf(stderr, "Test MGCP port parsing.\n");
+
+ port = bsc_mgcp_extract_port(mdcx_resp);
+ if (port != 4002) {
+ fprintf(stderr, "Could not parse port. Got: %d\n", port);
+ abort();
+ }
+}
+
int main(int argc, char **argv)
{
struct debug_target *stderr_target;
@@ -497,6 +510,7 @@
test_mgcp_find();
test_mgcp_rewrite();
test_mgcp_parse();
+ test_mgcp_parse_port();
return 0;
}