From 4db1dcd28181f83bca94db41f736d3d6f6aad8ed Mon Sep 17 00:00:00 2001
From: Nate Berkopec <nate.berkopec@gmail.com>
Date: Wed, 2 Aug 2017 18:50:50 -0600
Subject: [PATCH] Use Socket.ip_address_list to get loopback addresses (#1318)

---
 lib/puma/binder.rb | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/puma/binder.rb b/lib/puma/binder.rb
index cfd55a3b..eb9a1d2c 100644
--- a/lib/puma/binder.rb
+++ b/lib/puma/binder.rb
@@ -245,9 +245,10 @@ module Puma
       end
     end
 
-    def localhost_addresses
-      addrs = TCPSocket.gethostbyname "localhost"
-      addrs[3..-1].uniq
+    def loopback_addresses
+      Socket.ip_address_list.select do |addrinfo|
+        addrinfo.ipv6_loopback? || addrinfo.ipv4_loopback?
+      end.map { |addrinfo| addrinfo.ip_address }.uniq
     end
 
     # Tell the server to listen on host +host+, port +port+.
@@ -259,7 +260,7 @@ module Puma
     #
     def add_tcp_listener(host, port, optimize_for_latency=true, backlog=1024)
       if host == "localhost"
-        localhost_addresses.each do |addr|
+        loopback_addresses.each do |addr|
           add_tcp_listener addr, port, optimize_for_latency, backlog
         end
         return
@@ -298,7 +299,7 @@ module Puma
       MiniSSL.check
 
       if host == "localhost"
-        localhost_addresses.each do |addr|
+        loopback_addresses.each do |addr|
           add_ssl_listener addr, port, ctx, optimize_for_latency, backlog
         end
         return