From ad870c279e7c467707941e7ea61e9dbb2d170940 Mon Sep 17 00:00:00 2001
From: Alessio Garzi <agarzi@sipwise.com>
Date: Tue, 6 May 2025 15:56:59 +0200
Subject: [PATCH] MT#62756 CSC now sends Referred-By with callee local data in
 blind xfer

CSC-UI has been changed so that, during a blind transfer, the
Referred-By header is customized with local identity URI.
Without this customisation, jssip puts blindly the subscriber username
which is not always what kamailio proxy expects.

Having correct Referred-By header is important because kamailio proxy
uses this header in order to identify the transferor in a blind transfer call.
In particular, kamailio proxy checks if Referred-By matches custom header
P-Xfer-Firstcall-Callee-To, in this case B is recogized as transferor.

Change-Id: If149b34c16a5dc13116f8fea9a6d8046498753cd
---
 src/api/ngcp-call.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/api/ngcp-call.js b/src/api/ngcp-call.js
index 18df61a4..75c652be 100644
--- a/src/api/ngcp-call.js
+++ b/src/api/ngcp-call.js
@@ -458,8 +458,12 @@ export function callBlindTransfer (numberToTransfer) {
             }
         }
         try {
+            const uriString = `Referred-By: <sip:${rtcSession.local_identity.uri.user}@${rtcSession.local_identity.uri.host}>`
             rtcSession.refer(numberToTransfer, {
-                eventHandlers
+                eventHandlers,
+                extraHeaders: [
+                    uriString
+                ]
             })
         } catch (err) {
             reject(err)