INVITE from gw should have register_from_domain if it's available

lib/call-session.js

@@ -11,7 +11,7 @@ const makeInviteInProgressKey = (callid) => `sbc-out-iip${callid}`;
  * this is to make sure the outgoing From has the number in the incoming From
  * and not the incoming PAI
  */
-const createBLegFromHeader = (req, teams) => {
+const createBLegFromHeader = (req, teams, register_from_domain = null) => {
   const from = req.getParsedHeader('From');
   const uri = parseUri(from.uri);
   let user = uri.user || 'anonymous';
@@ -22,6 +22,8 @@ const createBLegFromHeader = (req, teams) => {
   else if (req.has('X-Preferred-From-User') || req.has('X-Preferred-From-Host')) {
     user = req.get('X-Preferred-From-User') || user;
     host = req.get('X-Preferred-From-Host') || host;
+  } else if (register_from_domain) {
+    host = register_from_domain;
   }
   if (from.name) {
     return `${from.name} <sip:${user}@${host}>`;
@@ -295,7 +297,8 @@ class CallSession extends Emitter {
                 name: vc.name,
                 diversion: vc.diversion,
                 hostport,
-                protocol: o.protocol
+                protocol: o.protocol,
+                register_from_domain: vc.register_from_domain
               };
               if (vc.register_username && vc.register_password) {
                 obj.auth = {
@@ -410,6 +413,12 @@ class CallSession extends Emitter {
               'Diversion': div
             };
           }
+          if (gw.register_from_domain) {
+            hdrs = {
+              ...hdrs,
+              'From': createBLegFromHeader(this.req, teams, gw.register_from_domain)
+            };
+          }
         }
         else this.logger.info(`sending INVITE to ${uri} via proxy ${proxy})`);
         try {