more restrictive checks before PRACKing in certain cases to fix #144

Author: James Criscuolo

src/Session.js

@@ -1806,10 +1806,20 @@ InviteClientContext.prototype = {
         Early media has been set up with at least one other different branch,
         but a final 2xx response hasn't been received
       */
+      if (this.dialog.pracked.indexOf(response.getHeader('rseq')) !== -1 ||
+          (this.dialog.pracked[this.dialog.pracked.length-1] >= response.getHeader('rseq') && this.dialog.pracked.length > 0)) {
+        return;
+      }
+
       if (!this.earlyDialogs[id] && !this.createDialog(response, 'UAC', true)) {
         return;
       }
 
+      if (this.earlyDialogs[id].pracked.indexOf(response.getHeader('rseq')) !== -1 ||
+          (this.earlyDialogs[id].pracked[this.earlyDialogs[id].pracked.length-1] >= response.getHeader('rseq') && this.earlyDialogs[id].pracked.length > 0)) {
+        return;
+      }
+
       extraHeaders.push('RAck: ' + response.getHeader('rseq') + ' ' + response.getHeader('cseq'));
       this.earlyDialogs[id].pracked.push(response.getHeader('rseq'));
 
@@ -1888,11 +1898,12 @@ InviteClientContext.prototype = {
               break;
             }
             this.hasAnswer = true;
+            this.dialog.pracked.push(response.getHeader('rseq'));
+
             this.mediaHandler.setDescription(response.body)
             .then(
               function onSuccess () {
                 extraHeaders.push('RAck: ' + response.getHeader('rseq') + ' ' + response.getHeader('cseq'));
-                session.dialog.pracked.push(response.getHeader('rseq'));
 
                 session.sendRequest(SIP.C.PRACK, {
                   extraHeaders: extraHeaders,

test/spec/SpecSession.js

@@ -1960,8 +1960,8 @@ describe('InviteClientContext', function() {
       expect(InviteClientContext.sendRequest).toHaveBeenCalledWith(SIP.C.ACK, {cseq: response.cseq});
     });
 
-    it('PRACKS any non 200 response when it already chose a dialog', function() {
-      InviteClientContext.dialog = { terminate: function() {} };
+    it('PRACKS any non 200 response that are not retransmissions when it already chose a dialog', function() {
+            InviteClientContext.dialog = { terminate: function() {}, pracked: [] };
       resp = SIP.Parser.parseMessage([
         'SIP/2.0 183 Session In Progress',
         'To: <sip:[email protected]>;tag=1ma2ki9411',