MT#58584 Do not add outbound_proxy in Route if exist

When outbound PRACK is challanged, SEMS is regenerating
the PRACK to proxy duplicating the proxy socket in the
Route header, with the result of:

Route: <sip:127.0.0.1:5062;lr>,
<sip:127.0.0.1:5062;lr=on;ftag=xyz;leg_b=1;did=f85.d281>,
<sip:127.0.0.1;r2=on;lr=on;ftag=xyz;ngcplb=yes>,
<sip:192.168.178.104;r2=on;lr=on;ftag=xyz;ngcplb=yes>

the duplicate "127.0.0.1:5062" is causing routing
issue on proxy, cause loose_route() function removes
only the first element. Then proxy sends PRACK to
itself.

To avoid that, we make sure is SEMS to do not add
the 'outbound_socket' value in the Route header
if that value already exist in the first position.

Change-Id: Id310144d8e77a99111e199358462496c9dd0495c

core/AmBasicSipDialog.cpp

@@ -129,8 +129,17 @@ string AmBasicSipDialog::getContactUri()
 string AmBasicSipDialog::getRoute() 
 {
   string res;
+  string route_first_element;
 
-  if(!outbound_proxy.empty() && (force_outbound_proxy || remote_tag.empty())){
+  if (!route.empty()) {
+    route_first_element = route.substr(0, route.find(','));
+  }
+
+  // Do no add outbound_proxy if it's already the top most Route
+  if(!outbound_proxy.empty() &&
+    (force_outbound_proxy || remote_tag.empty()) &&
+    route_first_element.find(outbound_proxy) == std::string::npos)
+  {
     res += "<" + outbound_proxy + ";lr>";
 
     if(!route.empty()) {