From dc21e28e1fa29202977344cea2bd86a3fba755c6 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Tue, 22 Jan 2019 17:35:53 -0800
Subject: [PATCH] Fix parsing XOR-MAPPED-ADDRESS if the optional comprehension
 bit is set

---
 src/SimpleStun.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/SimpleStun.c b/src/SimpleStun.c
index f4b256d..3867fa1 100644
--- a/src/SimpleStun.c
+++ b/src/SimpleStun.c
@@ -133,7 +133,8 @@ int LiFindExternalAddressIP4(const char* stunServer, unsigned short stunPort, un
             Limelog("STUN attribute out of bounds: %d\n", htons(attribute->length));
             return -5;
         }
-        else if (htons(attribute->type) != STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS) {
+        // Mask off the comprehension bit
+        else if ((htons(attribute->type) & 0x7FFF) != STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS) {
             // Continue searching if this wasn't our address
             bytesRead -= sizeof(*attribute) + htons(attribute->length);
             attribute = (PSTUN_ATTRIBUTE_HEADER)(((char*)attribute) + sizeof(*attribute) + htons(attribute->length));