From 092cdfa79fa8b65a633734f5da73fbd8e9455d07 Mon Sep 17 00:00:00 2001
From: Eric Watson <wasnotrice@gmail.com>
Date: Tue, 24 Sep 2019 08:46:20 -0500
Subject: [PATCH] Delete cached interface after stopping

This fixes an issue where the library could use a stale multicast
address.

Steps to reproduce:

1. Connect to a wifi network
2. Start a dnssd browser
3. Stop the dnssd browser
4. Connect to a different wifi network
5. Start a dnssd browser

An error like this is thrown:

Error: setMulticastInterface EADDRNOTAVAIL
    at Socket.setMulticastInterface (dgram.js:566:11)
    at Socket.eval (webpack:///./node_modules/dnssd/lib/NetworkInterface.js?:238:41)
    at Socket.emit (events.js:182:13)
    at startListening (dgram.js:128:10)
    at state.handle.lookup (dgram.js:249:7)
    at process._tickCallback (internal/process/next_tick.js:63:19)

This is because we are still using the IP address from the first
NetworkInterface instance, even though it is not valid for the new
network. Clearing the interface from `activeInterfaces` on stop solves
the problem.
---
 lib/NetworkInterface.js             | 9 +++++++++
 src/NetworkInterface.js             | 9 +++++++++
 test/tests/NetworkInterface.test.js | 9 +++++++++
 3 files changed, 27 insertions(+)

diff --git a/lib/NetworkInterface.js b/lib/NetworkInterface.js
index c2b470b..dd93959 100644
--- a/lib/NetworkInterface.js
+++ b/lib/NetworkInterface.js
@@ -428,6 +428,15 @@ NetworkInterface.prototype.stop = function () {
   this._sockets = [];
   this._buffers = [];
 
+  var intf = this;
+
+  // Remove any entries from active interfaces.
+  Object.keys(activeInterfaces).forEach(function (name) {
+    if (activeInterfaces[name] === intf) {
+      delete activeInterfaces[name];
+    }
+  });
+
   debug('Done.');
 };
 
diff --git a/src/NetworkInterface.js b/src/NetworkInterface.js
index d342e4c..fc5f654 100644
--- a/src/NetworkInterface.js
+++ b/src/NetworkInterface.js
@@ -421,6 +421,15 @@ NetworkInterface.prototype.stop = function() {
   this._sockets = [];
   this._buffers = [];
 
+  const intf = this;
+
+  // Remove any entries from active interfaces.
+  Object.keys(activeInterfaces).forEach((name) => {
+    if (activeInterfaces[name] === intf) {
+      delete activeInterfaces[name];
+    }
+  });
+
   debug('Done.');
 };
 
diff --git a/test/tests/NetworkInterface.test.js b/test/tests/NetworkInterface.test.js
index 4fd7225..ec02c83 100644
--- a/test/tests/NetworkInterface.test.js
+++ b/test/tests/NetworkInterface.test.js
@@ -604,6 +604,15 @@ describe('NetworkInterface', function() {
       intf._sockets = [socket];
       intf.stop();
     });
+
+    it.only('should remove interface from active interfaces cache', function() {
+      const intf = new NetworkInterface.get();
+
+      intf.stop();
+      const newIntf = new NetworkInterface.get();
+
+      expect(newIntf).to.not.equal(intf)
+    });
   });
 
 });