network: autdetect rtp bind ip-address
Currently there are two ways to set the rtp bind ip-address (local
ip address where the rtp streams are bound to). It is possible to
set no set an rtp bind ip, if none no address is configured, then
the ip address where the mgcp service is bound to is used.
On a system with multiple network interfaces it is likely that
there are the remote end is not reachable through the interface
that has been configured. In this case rtp ip-probing can be
enabled via vty option in order to automatically detect the
ip address of the interface that points towards the remote end.
The autodetection can only work if the ip-address is known when
a CRCX is performed. For this the remote entity must include the
remote ip address in the sdp trailer.
Implement probing to determine te right local ip address
Add debug log to display which ip address is actually used
Add a VTY option for the probing functionality.
Change-Id: Ia57cf7dab8421fd3ab6e1515727db0080373485e
diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 3d52d07..7876b33 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -32,6 +32,7 @@
#include <osmocom/core/msgb.h>
#include <osmocom/core/select.h>
+#include <osmocom/core/socket.h>
#include <osmocom/netif/rtp.h>
#include <osmocom/mgcp/mgcp.h>
#include <osmocom/mgcp/mgcp_common.h>
@@ -52,6 +53,56 @@
MGCP_PROTO_RTCP,
};
+/*! Determine the local rtp bind IP-address.
+ * \param[out] addr caller provided memory to store the resulting IP-Address
+ * \param[in] endp mgcp endpoint, that holds a copy of the VTY parameters
+ *
+ * The local bind IP-address is automatically selected by probing the
+ * IP-Address of the interface that is pointing towards the remote IP-Address,
+ * if no remote IP-Address is known yet, the statically configured
+ * IP-Addresses are used as fallback. */
+void mgcp_get_local_addr(char *addr, struct mgcp_conn_rtp *conn)
+{
+
+ struct mgcp_endpoint *endp;
+ int rc;
+ endp = conn->conn->endp;
+
+ /* Try probing the local IP-Address */
+ if (endp->cfg->net_ports.bind_addr_probe && conn->end.addr.s_addr != 0) {
+ rc = osmo_sock_local_ip(addr, inet_ntoa(conn->end.addr));
+ if (rc < 0)
+ LOGP(DRTP, LOGL_ERROR,
+ "endpoint:%x CI:%i local interface auto detection failed, using configured addresses...\n",
+ ENDPOINT_NUMBER(endp), conn->conn->id);
+ else {
+ LOGP(DRTP, LOGL_DEBUG,
+ "endpoint:%x CI:%i selected local rtp bind ip %s by probing using remote ip %s\n",
+ ENDPOINT_NUMBER(endp), conn->conn->id, addr,
+ inet_ntoa(conn->end.addr));
+ return;
+ }
+ }
+
+ /* Select from preconfigured IP-Addresses */
+ if (endp->cfg->net_ports.bind_addr) {
+ /* Check there is a bind IP for the RTP traffic configured,
+ * if so, use that IP-Address */
+ strncpy(addr, endp->cfg->net_ports.bind_addr, INET_ADDRSTRLEN);
+ LOGP(DRTP, LOGL_DEBUG,
+ "endpoint:%x CI:%i using configured rtp bind ip as local bind ip %s\n",
+ ENDPOINT_NUMBER(endp), conn->conn->id, addr);
+ } else {
+ /* No specific bind IP is configured for the RTP traffic, so
+ * assume the IP where we listen for incoming MGCP messages
+ * as bind IP */
+ strncpy(addr, endp->cfg->source_addr, INET_ADDRSTRLEN);
+ LOGP(DRTP, LOGL_DEBUG,
+ "endpoint:%x CI:%i using mgcp bind ip as local rtp bind ip: %s\n",
+ ENDPOINT_NUMBER(endp), conn->conn->id, addr);
+ }
+}
+
/* This does not need to be a precision timestamp and
* is allowed to wrap quite fast. The returned value is
* 1/codec_rate seconds. */
@@ -1158,6 +1209,7 @@
{
char name[512];
struct mgcp_rtp_end *end;
+ char local_ip_addr[INET_ADDRSTRLEN];
snprintf(name, sizeof(name), "%s-%u", conn->conn->name, conn->conn->id);
end = &conn->end;
@@ -1182,7 +1234,9 @@
end->rtcp.data = conn;
end->rtcp.cb = rtp_data_net;
- return bind_rtp(endp->cfg, mgcp_net_src_addr(endp), end,
+ mgcp_get_local_addr(local_ip_addr, conn);
+
+ return bind_rtp(endp->cfg, local_ip_addr, end,
ENDPOINT_NUMBER(endp));
}