add support for sitting behind a sip proxy that adds X-Forwarded-For header

lib/call-session.js

@@ -136,7 +136,14 @@ class CallSession extends Emitter {
         proxy,
         headers,
         responseHeaders,
-        proxyRequestHeaders: ['all', '-Authorization', '-Max-Forwards', '-Record-Route', '-Session-Expires', 'Min-SE'],
+        proxyRequestHeaders: [
+          'all',
+          '-Authorization',
+          '-Max-Forwards',
+          '-Record-Route',
+          '-Session-Expires',
+          '-X-Forwarded-For'
+        ],
         proxyResponseHeaders: ['all'],
         localSdpB: response.sdp,
         localSdpA: async(sdp, res) => {

lib/middleware.js

@@ -73,6 +73,24 @@ module.exports = function(srf, logger) {
 
   const initLocals = (req, res, next) => {
     req.locals = req.locals || {};
+
+    /* check if forwarded by a proxy that applied an X-Forwarded-For Header */
+    if (req.has('X-Forwarded-For')) {
+      const arr = /^([^:]*)(?::(.*))?$/.exec(req.get('X-Forwarded-For'));
+      if (arr) {
+        const original_source_address = arr[1];
+        const original_source_port = arr[2] || req.source_port;
+        logger({
+          callId: req.get('Call-ID'),
+          original_source_address,
+          original_source_port,
+          proxy_source_address: req.source_address,
+          proxy_source_port: req.source_port
+        }, 'overwriting source address and port for proxied SIP INVITE');
+        req.source_address = original_source_address;
+        req.source_port = original_source_port;
+      }
+    }
     req.locals.cdr = initCdr(req);
     const callId = req.get('Call-ID');
     req.on('cancel', () => {