bugfix: PAI header on incoming call was being put in From header of outbound call

lib/call-session.js

@@ -2,8 +2,20 @@ const Emitter = require('events');
 const {makeRtpEngineOpts} = require('./utils');
 const {forwardInDialogRequests} = require('drachtio-fn-b2b-sugar');
 const {SipError} = require('drachtio-srf');
+const {parseUri} = require('drachtio-srf');
 const debug = require('debug')('jambonz:sbc-outbound');
 
+/**
+ * this is to make sure the outgoing From has the number in the incoming From
+ * and not the incoming PAI
+ */
+const createBLegFromHeader = (req) => {
+  const from = req.getParsedHeader('From');
+  const uri = parseUri(from.uri);
+  if (uri && uri.user) return `sip:${uri.user}@localhost`;
+  return 'sip:anonymous@localhost';
+};
+
 class CallSession extends Emitter {
   constructor(logger, req, res) {
     super();
@@ -86,6 +98,9 @@ class CallSession extends Emitter {
             passFailure: false,
             proxyRequestHeaders: ['all'],
             proxyResponseHeaders: ['all'],
+            headers: {
+              'From': createBLegFromHeader(this.req)
+            },
             localSdpB: response.sdp,
             localSdpA: async(sdp, res) => {
               this.toTag = res.getParsedHeader('To').params.tag;