From 4e2863294d2a994d34eb03fde5ec9a62f8a567fd Mon Sep 17 00:00:00 2001
From: Benau <Benau@users.noreply.github.com>
Date: Fri, 2 Mar 2018 22:38:04 +0800
Subject: [PATCH] Use stun servers that return XOR mapped address

---
 src/config/user_config.hpp | 26 ++++++--------------------
 src/network/stk_host.cpp   | 31 ++++++++++++++++++++++++-------
 2 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/src/config/user_config.hpp b/src/config/user_config.hpp
index 1b5bbbb7e..cb51eadcf 100644
--- a/src/config/user_config.hpp
+++ b/src/config/user_config.hpp
@@ -719,31 +719,17 @@ namespace UserConfigParams
     PARAM_PREFIX StringListUserConfigParam         m_stun_servers
             PARAM_DEFAULT(  StringListUserConfigParam("Stun_servers", "The stun servers"
                             " that will be used to know the public address.",
-                            24,
-                            "provserver.televolution.net",
-                            "sip1.lakedestiny.cordiaip.com",
-                            "stun1.voiceeclipse.net",
-                            "stun01.sipphone.com",
+                            10,
+                            "stun.cope.es",
+                            "stun.12connect.com",
                             "stun.callwithus.com",
                             "stun.counterpath.net",
-                            "stun.endigovoip.com",
                             "stun.ekiga.net",
-                            "stun.ideasip.com",
-                            "stun.internetcalls.com",
-                            "stun.ipns.com",
-                            "stun.noc.ams-ix.net",
-                            "stun.phonepower.com",
-                            "stun.phoneserve.com",
-                            "stun.rnktel.com",
-                            "stun.softjoys.com",
-                            "stunserver.org",
-                            "stun.sipgate.net",
+                            "stun.schlund.de",
                             "stun.stunprotocol.org",
                             "stun.voip.aebc.com",
-                            "stun.voipbuster.com",
-                            "stun.voxalot.com",
-                            "stun.voxgratia.org",
-                            "stun.xten.com") );
+                            "numb.viagenie.ca",
+                            "stun.ivao.aero") );
 
     // ---- Gamemode setup
     PARAM_PREFIX IntToIntUserConfigParam m_num_karts_per_gamemode
diff --git a/src/network/stk_host.cpp b/src/network/stk_host.cpp
index 44de7cab8..4fe1e25cb 100644
--- a/src/network/stk_host.cpp
+++ b/src/network/stk_host.cpp
@@ -506,12 +506,11 @@ void STKHost::setPublicAddress()
 
         // The stun message is valid, so we parse it now:
         // Those are the port and the address to be detected
-        bool found = false;
+        TransportAddress non_xor_addr, xor_addr;
         while (true)
         {
             if (response.size() < 4)
             {
-                Log::error("STKHost", "STUN response is invalid.");
                 break;
             }
             unsigned type = response.getUInt16();
@@ -558,11 +557,14 @@ void STKHost::setPublicAddress()
                     // Obfuscation is described in Section 15.2 of RFC 5389.
                     port ^= magic_cookie >> 16;
                     ip ^= magic_cookie;
+                    xor_addr.setPort(port);
+                    xor_addr.setIP(ip);
+                }
+                else
+                {
+                    non_xor_addr.setPort(port);
+                    non_xor_addr.setIP(ip);
                 }
-                m_public_address.setPort(port);
-                m_public_address.setIP(ip);
-                found = true;
-                break;
             }   // type == mapped_address || type == xor_mapped_address
             else
             {
@@ -573,8 +575,23 @@ void STKHost::setPublicAddress()
             }
         }   // while true
         // Found public address and port
-        if (found)
+        if (!xor_addr.isUnset() || !non_xor_addr.isUnset())
+        {
+            // Use XOR mapped address when possible to avoid translation of
+            // the packet content by application layer gateways (ALGs) that
+            // perform deep packet inspection in an attempt to perform
+            // alternate NAT traversal methods.
+            if (!xor_addr.isUnset())
+            {
+                m_public_address.copy(xor_addr);
+            }
+            else
+            {
+                Log::warn("STKHost", "Only non xor-mapped address returned.");
+                m_public_address.copy(non_xor_addr);
+            }
             untried_server.clear();
+        }
     }
 }   // setPublicAddress