From d4200b6ba3ff95805c045f1a6752ed3c3cc2227e Mon Sep 17 00:00:00 2001
From: Donat Zenichev <dzenichev@sipwise.com>
Date: Fri, 25 Jul 2025 13:25:33 +0200
Subject: [PATCH] MT#63298 AmB2BSession: introduce `addFakeSDPbasedOnPort()`

A helper to generate fake AmMimeBody based on given port.
No functional change.

Change-Id: Id9263a80fc47f554f315169c079875c8dfd0a581
---
 core/AmB2BSession.cpp | 31 ++++++++++++++++++-------------
 core/AmB2BSession.h   |  3 +++
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/core/AmB2BSession.cpp b/core/AmB2BSession.cpp
index e573df76..2cfedd36 100644
--- a/core/AmB2BSession.cpp
+++ b/core/AmB2BSession.cpp
@@ -285,6 +285,23 @@ static void sdp2body(const AmSdp &sdp, AmMimeBody &body)
   else body.parse(SIP_APPLICATION_SDP, (const unsigned char*)body_str.c_str(), body_str.length());
 }
 
+void AmB2BSession::addFakeSDPbasedOnPort(const AmMimeBody *src_sdp, AmMimeBody &new_body,
+                                         unsigned int& desired_port)
+{
+  /* create fake AmSdp from AmMimeBody */
+  AmSdp fake_sdp;
+  AmMimeBody fake_mimebody;
+  fake_sdp.parse((const char *)src_sdp->getPayload());
+
+  for (auto it = fake_sdp.media.begin(); it != fake_sdp.media.end(); ++it)
+  {
+    it->port = desired_port;
+  }
+
+  sdp2body(fake_sdp, fake_mimebody);
+  createFakeReply(&fake_mimebody, new_body);
+}
+
 void AmB2BSession::acceptPendingInvite(AmSipRequest *invite)
 {
   // reply the INVITE with fake 200 reply
@@ -321,19 +338,7 @@ void AmB2BSession::acceptPendingInviteB2B(const AmSipRequest& invite)
 
   if (remote_port > 0) {
     ILOG_DLG(L_DBG, "Using remotely seen SDP port for faking this reply: '%d'\n", remote_port);
-
-    /* create fake AmSdp from AmMimeBody */
-    AmSdp fake_sdp;
-    AmMimeBody fake_mimebody;
-    fake_sdp.parse((const char *)sdp->getPayload());
-
-    for (auto it = fake_sdp.media.begin(); it != fake_sdp.media.end(); ++it)
-    {
-      it->port = remote_port;
-    }
-
-    sdp2body(fake_sdp, fake_mimebody);
-    createFakeReply(&fake_mimebody, n_reply.body);
+    addFakeSDPbasedOnPort(sdp, n_reply.body, remote_port);
   }
   else {
     createFakeReply(sdp, n_reply.body);
diff --git a/core/AmB2BSession.h b/core/AmB2BSession.h
index 290156d4..3bce1913 100644
--- a/core/AmB2BSession.h
+++ b/core/AmB2BSession.h
@@ -210,6 +210,9 @@ private:
   /** generate fake body (c=0.0.0.0) reply */
   void createFakeReply(const AmMimeBody *sdp,   AmMimeBody& reply_body);
 
+  /** create fake AmSipReply. SDP body based on SDP offer, but with a desired port */
+  void addFakeSDPbasedOnPort(const AmMimeBody *src_sdp, AmMimeBody &new_body, unsigned int& desired_port);
+
   /** generate 200 SIP reply on a pending INVITE (uses fake body) */
   virtual void acceptPendingInvite(AmSipRequest *invite);