From 98af46c55cdfc1a5b1b518f54703654931a1b009 Mon Sep 17 00:00:00 2001
From: Peter Griess <pgriess@fb.com>
Date: Thu, 13 Aug 2015 10:19:09 -0700
Subject: [PATCH] Set IPV6_V6ONLY in folly::AsyncUDPServerSocket

Summary: - This mirrors the behavior in AsyncServerSocket

Reviewed By: @yfeldblum

Differential Revision: D2338665
---
 folly/io/async/AsyncUDPSocket.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/folly/io/async/AsyncUDPSocket.cpp b/folly/io/async/AsyncUDPSocket.cpp
index 5b128126..1364ed3f 100644
--- a/folly/io/async/AsyncUDPSocket.cpp
+++ b/folly/io/async/AsyncUDPSocket.cpp
@@ -91,6 +91,18 @@ void AsyncUDPSocket::bind(const folly::SocketAddress& address) {
     }
   }
 
+  // If we're using IPv6, make sure we don't accept V4-mapped connections
+  if (address.getFamily() == AF_INET6) {
+    int flag = 1;
+    if (::setsockopt(socket, IPPROTO_IPV6, IPV6_V6ONLY,
+                     &flag, sizeof(flag))) {
+      throw AsyncSocketException(
+        AsyncSocketException::NOT_OPEN,
+        "Failed to set IPV6_V6ONLY",
+        errno);
+    }
+  }
+
   // bind to the address
   sockaddr_storage addrStorage;
   address.getAddress(&addrStorage);
-- 
2.34.1