MT#61912 OA: save the established body when it's generated

When OA generates own SDP body (e.g. case with
accepted invite in DSP), save it as established_body
for this leg, in order to be able to re-invite
this leg later.

It can happen there is still no SDP seen from the
callee side (other side), and in case we want to
send established re-invite towards this leg,
this will fail, since no SDP body seen yet.

Change-Id: Ifd9f0fb70d27deac871de4eed1648f7c152813f3

apps/dsm/mods/mod_dlg/ModDlg.cpp

@@ -182,14 +182,22 @@ EXEC_ACTION_START(DLGAcceptInviteAction) {
 
   try {
     AmMimeBody sdp_body;
-    if(sess->dlg->reply(*sc_sess->last_req.get(),code_i, reason,
-		       sdp_body.addPart(SIP_APPLICATION_SDP), hdrs) != 0)
+    /* save generated SDP body for this session as `established_body`  */
+    if(sess->dlg->reply(*sc_sess->last_req.get(),
+                        code_i,
+                        reason,
+                        sdp_body.addPart(SIP_APPLICATION_SDP),
+                        hdrs,
+                        SIP_FLAGS_SAVE_ESTB_SDP) != 0)
+    {
       throw AmSession::Exception(500,"could not send response");
+    }
 
   }catch(const AmSession::Exception& e){
 
     ERROR("%i %s\n",e.code,e.reason.c_str());
     sess->setStopped();
+
     sess->dlg->reply(*sc_sess->last_req.get(),e.code,e.reason);
 
     sc_sess->SET_ERRNO(DSM_ERRNO_DLG);

core/AmBasicSipDialog.h

@@ -45,6 +45,8 @@ using std::string;
 
 #define SIP_FLAGS_NOBL         1<<4 // do not use destination blacklist
 
+#define SIP_FLAGS_SAVE_ESTB_SDP 1<<10 // save established SDP body when processing in OA, see `AmOfferAnswer::onReplyOut()`
+
 /** \brief SIP transaction representation */
 struct AmSipTransaction
 {

core/AmOfferAnswer.cpp

@@ -361,7 +361,7 @@ int AmOfferAnswer::onRequestOut(AmSipRequest& req)
   return 0;
 }
 
-int AmOfferAnswer::onReplyOut(AmSipReply& reply, bool no_sdp_generation)
+int AmOfferAnswer::onReplyOut(AmSipReply& reply, int &flags, AmMimeBody &ret_body, bool no_sdp_generation)
 {
   AmMimeBody* sdp_body = reply.body.hasContentType(SIP_APPLICATION_SDP);
   AmMimeBody* csta_body = reply.body.hasContentType(SIP_APPLICATION_CSTA_XML);
@@ -409,7 +409,6 @@ int AmOfferAnswer::onReplyOut(AmSipReply& reply, bool no_sdp_generation)
         }
 
         sdp_body->setPayload((const unsigned char*)existing_sdp.c_str(), existing_sdp.length());
-
         has_sdp = true;
         DBG("Now has_sdp has been reset to true.\n");
 
@@ -469,6 +468,14 @@ int AmOfferAnswer::onReplyOut(AmSipReply& reply, bool no_sdp_generation)
 
       sdp_body->setPayload((const unsigned char*)sdp_buf.c_str(), sdp_buf.length());
       has_sdp = true;
+
+      /* some of sessions want generated body to be kept for the future, e.g. for the case
+        * when we want to reinvite the other side, before this side got actual SDP answer.
+        * e.g. this happens in DSM, when we generate faked SDP in some cases. */
+      if (flags & SIP_FLAGS_SAVE_ESTB_SDP) {
+        DBG("Saving established_body based on newly generated SDP.\n");
+        ret_body = *sdp_body;
+      }
     }
 
   } else if (sdp_body && has_sdp) {

core/AmOfferAnswer.h

@@ -86,7 +86,7 @@ public:
   int onReplyIn(const AmSipReply& reply);
   int onRequestOut(AmSipRequest& req);
   /* `no_sdp_generation` - can be used for cases like absent SDP in coming INVITE */
-  int onReplyOut(AmSipReply& reply, bool no_sdp_generation = false);
+  int onReplyOut(AmSipReply& reply, int &flags, AmMimeBody &ret_body, bool no_sdp_generation = false);
   int onRequestSent(const AmSipRequest& req);
   int onReplySent(const AmSipReply& reply);
   void onNoAck(unsigned int ack_cseq);

core/AmSipDialog.cpp

@@ -271,8 +271,15 @@ int AmSipDialog::onTxRequest(AmSipRequest& req, int& flags)
 int AmSipDialog::onTxReply(const AmSipRequest& req, AmSipReply& reply, int& flags)
 {
   if (offeranswer_enabled) {
-    if(oa.onReplyOut(reply, req.body.empty()) < 0)
+    AmMimeBody sdp_body;
+    if(oa.onReplyOut(reply, flags, sdp_body, req.body.empty()) < 0)
       return -1;
+
+    /* if generated by OA, save it */
+    if (!sdp_body.empty()) {
+      DBG("OA generated an SDP body, saving as established_body.\n");
+      established_body = sdp_body;
+    }
   }
 
   rel100.onReplyOut(reply);