Store the private IP in redis when a client registers (#113)

* add srf.locals.privateSipAddress

* add private SBC address in client redis data

* lint

lib/register.js

@@ -32,6 +32,7 @@ async function register(logger, req, res) {
     const opts = {
       contact: req.getParsedHeader('Contact')[0].uri,
       sbcAddress: req.server.hostport,
+      privateSbcAddress: req.srf.locals.privateSipAddress,
       protocol: getSipProtocol(req),
       proxy: `sip:${req.source_address}:${req.source_port}`,
       callHook: req.authorization.grant.call_hook,