From c929f4fb69dce92e4294680baa0671d1c5953da6 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Fri, 23 Nov 2007 22:14:33 +0000
Subject: [PATCH] fix for systems where IPv6 sockets bound to INADDR_ANY also
 listens on IPv4 connections

---
 include/libtorrent/aux_/session_impl.hpp |  2 +-
 include/libtorrent/socket.hpp            | 15 +++++++++++++++
 src/session_impl.cpp                     |  6 ++++--
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index 090196a4f..95089b649 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -473,7 +473,7 @@ namespace libtorrent
 			// we might need more than one listen socket
 			std::list<listen_socket_t> m_listen_sockets;
 
-			listen_socket_t setup_listener(tcp::endpoint ep, int retries);
+			listen_socket_t setup_listener(tcp::endpoint ep, int retries, bool v6_only = false);
 
 			// the settings for the client
 			session_settings m_settings;
diff --git a/include/libtorrent/socket.hpp b/include/libtorrent/socket.hpp
index 514be256c..499842dd7 100755
--- a/include/libtorrent/socket.hpp
+++ b/include/libtorrent/socket.hpp
@@ -171,6 +171,21 @@ namespace libtorrent
 			return Endpoint(addr, port);
 		}
 	}
+
+	struct v6only
+	{
+		v6only(bool enable): m_value(enable) {}
+		template<class Protocol>
+		int level(Protocol const&) const { return IPPROTO_IPV6; }
+		template<class Protocol>
+		int name(Protocol const&) const { return IPV6_V6ONLY; }
+		template<class Protocol>
+		int const* data(Protocol const&) const { return &m_value; }
+		template<class Protocol>
+		size_t size(Protocol const&) const { return sizeof(m_value); }
+		int m_value;
+	};
+	
 }
 
 #endif // TORRENT_SOCKET_HPP_INCLUDED
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 3c8625fef..69f2c1bc1 100755
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -814,13 +814,15 @@ namespace detail
 		return m_ipv6_interface;
 	}
 
-	session_impl::listen_socket_t session_impl::setup_listener(tcp::endpoint ep, int retries)
+	session_impl::listen_socket_t session_impl::setup_listener(tcp::endpoint ep
+		, int retries, bool v6_only)
 	{
 		asio::error_code ec;
 		listen_socket_t s;
 		s.sock.reset(new socket_acceptor(m_io_service));
 		s.sock->open(ep.protocol(), ec);
 		s.sock->set_option(socket_acceptor::reuse_address(true), ec);
+		if (ep.protocol() == tcp::v6()) s.sock->set_option(v6only(v6_only), ec);
 		s.sock->bind(ep, ec);
 		while (ec && retries > 0)
 		{
@@ -913,7 +915,7 @@ namespace detail
 
 			s = setup_listener(
 				tcp::endpoint(address_v6::any(), m_listen_interface.port())
-				, m_listen_port_retries);
+				, m_listen_port_retries, true);
 
 			if (s.sock)
 			{