add getObservedAddrs feature to every returned conn

package.json

@@ -40,6 +40,7 @@
     "tape": "^4.2.0"
   },
   "dependencies": {
+    "ip-address": "^5.8.0",
     "multiaddr": "^1.0.0"
   }
 }

src/index.js

@@ -2,6 +2,7 @@
 // const log = debug('libp2p:tcp')
 const tcp = require('net')
 const multiaddr = require('multiaddr')
+const Address6 = require('ip-address').Address6
 
 exports = module.exports = TCP
 
@@ -17,7 +18,11 @@ function TCP () {
       options = {}
     }
     options.ready = options.ready || function noop () {}
-    return tcp.connect(multiaddr.toOptions(), options.ready)
+    const conn = tcp.connect(multiaddr.toOptions(), options.ready)
+    conn.getObservedAddrs = () => {
+      return [multiaddr]
+    }
+    return conn
   }
 
   this.createListener = (multiaddrs, options, handler, callback) => {
@@ -35,7 +40,12 @@ function TCP () {
     const freshMultiaddrs = []
 
     multiaddrs.forEach((m) => {
-      const listener = tcp.createServer(handler)
+      const listener = tcp.createServer((conn) => {
+        conn.getObservedAddrs = () => {
+          return [getMultiaddr(conn)]
+        }
+        handler(conn)
+      })
       listener.listen(m.toOptions(), () => {
         // Node.js likes to convert addr to IPv6 (when 0.0.0.0 for e.g)
         const address = listener.address()
@@ -71,3 +81,20 @@ function TCP () {
   }
 }
 
+function getMultiaddr (conn) {
+  var mh
+
+  if (conn.remoteFamily === 'IPv6') {
+    var addr = new Address6(conn.remoteAddress)
+    if (addr.v4) {
+      var ip4 = addr.to4().correctForm()
+      mh = multiaddr('/ip4/' + ip4 + '/tcp/' + conn.remotePort)
+    } else {
+      mh = multiaddr('/ip6/' + conn.remoteAddress + '/tcp/' + conn.remotePort)
+    }
+  } else {
+    mh = multiaddr('/ip4/' + conn.remoteAddress + '/tcp/' + conn.remotePort)
+  }
+
+  return mh
+}

tests/libp2p-tcp-test.js

@@ -53,5 +53,29 @@ describe('libp2p-tcp', function () {
     })
   })
 
+  it('get observed addrs', (done) => {
+    const mh = multiaddr('/ip4/127.0.0.1/tcp/9090')
+    var dialerObsAddrs
+    var listenerObsAddrs
+
+    tcp.createListener(mh, (conn) => {
+      expect(conn).to.exist
+      dialerObsAddrs = conn.getObservedAddrs()
+      conn.end()
+    }, () => {
+      const conn = tcp.dial(mh)
+      conn.on('end', () => {
+        listenerObsAddrs = conn.getObservedAddrs()
+        conn.end()
+
+        tcp.close(() => {
+          expect(listenerObsAddrs[0]).to.deep.equal(mh)
+          expect(dialerObsAddrs.length).to.equal(1)
+          done()
+        })
+      })
+    })
+  })
+
   it.skip('listen on IPv6', (done) => {})
 })