improved IPv6 support (skips unsupported tests on windows)

include/libtorrent/broadcast_socket.hpp

@@ -48,6 +48,9 @@ namespace libtorrent
 	TORRENT_EXPORT bool is_any(address const& addr);
 	TORRENT_EXPORT int cidr_distance(address const& a1, address const& a2);
 
+	// determines if the operating system supports IPv6
+	TORRENT_EXPORT bool supports_ipv6();
+
 	int common_bits(unsigned char const* b1
 		, unsigned char const* b2, int n);
 

src/broadcast_socket.cpp

@@ -51,7 +51,9 @@ namespace libtorrent
 {
 	bool is_local(address const& a)
 	{
+#if TORRENT_USE_IPV6
 		if (a.is_v6()) return a.to_v6().is_link_local();
+#endif
 		address_v4 a4 = a.to_v4();
 		unsigned long ip = a4.to_ulong();
 		return ((ip & 0xff000000) == 0x0a000000
@@ -61,28 +63,51 @@ namespace libtorrent
 
 	bool is_loopback(address const& addr)
 	{
+#if TORRENT_USE_IPV6
 		if (addr.is_v4())
-		  return addr.to_v4() == address_v4::loopback();
+			return addr.to_v4() == address_v4::loopback();
 		else
 			return addr.to_v6() == address_v6::loopback();
+#else
+		return addr.to_v4() == address_v4::loopback();
+#endif
 	}
 
 	bool is_multicast(address const& addr)
 	{
+#if TORRENT_USE_IPV6
 		if (addr.is_v4())
 			return addr.to_v4().is_multicast();
 		else
 			return addr.to_v6().is_multicast();
+#else
+		return addr.to_v4().is_multicast();
+#endif
 	}
 
 	bool is_any(address const& addr)
 	{
+#if TORRENT_USE_IPV6
 		if (addr.is_v4())
 			return addr.to_v4() == address_v4::any();
 		else if (addr.to_v6().is_v4_mapped())
 			return (addr.to_v6().to_v4() == address_v4::any());
 		else
 			return addr.to_v6() == address_v6::any();
+#else
+		return addr.to_v4() == address_v4::any();
+#endif
+	}
+
+	bool supports_ipv6()
+	{
+#if TORRENT_USE_IPV6
+		error_code ec;
+		address::from_string("::1", ec);
+		return !ec;
+#else
+		return false;
+#endif
 	}
 
 	address guess_local_address(io_service& ios)
@@ -128,13 +153,16 @@ namespace libtorrent
 	// between the addresses.
 	int cidr_distance(address const& a1, address const& a2)
 	{
+#if TORRENT_USE_IPV6
 		if (a1.is_v4() && a2.is_v4())
 		{
+#endif
 			// both are v4
 			address_v4::bytes_type b1 = a1.to_v4().to_bytes();
 			address_v4::bytes_type b2 = a2.to_v4().to_bytes();
 			return address_v4::bytes_type::static_size * 8
 				- common_bits(b1.c_array(), b2.c_array(), b1.size());
+#if TORRENT_USE_IPV6
 		}
 	
 		address_v6::bytes_type b1;
@@ -145,6 +173,7 @@ namespace libtorrent
 		else b2 = a2.to_v6().to_bytes();
 		return address_v6::bytes_type::static_size * 8
 			- common_bits(b1.c_array(), b2.c_array(), b1.size());
+#endif
 	}
 
 	broadcast_socket::broadcast_socket(io_service& ios

src/session_impl.cpp

@@ -737,27 +737,19 @@ namespace aux {
 			}
 
 #if TORRENT_USE_IPV6
-#ifdef TORRENT_WINDOWS
 			// only try to open the IPv6 port if IPv6 is installed
-			SOCKADDR_STORAGE storage;
-			int len = sizeof(storage);
-			if (WSAStringToAddressA("::1", AF_INET6, 0,
-				(sockaddr*)&storage, &len) != SOCKET_ERROR)
+			if (supports_ipv6())
 			{
-#endif
+				s = setup_listener(
+					tcp::endpoint(address_v6::any(), m_listen_interface.port())
+					, m_listen_port_retries, true);
 
-			s = setup_listener(
-				tcp::endpoint(address_v6::any(), m_listen_interface.port())
-				, m_listen_port_retries, true);
-
-			if (s.sock)
-			{
-				m_listen_sockets.push_back(s);
-				async_accept(s.sock);
+				if (s.sock)
+				{
+					m_listen_sockets.push_back(s);
+					async_accept(s.sock);
+				}
 			}
-#ifdef TORRENT_WINDOWS
-			}
-#endif
 #endif // TORRENT_USE_IPV6
 
 			// set our main IPv4 and IPv6 interfaces

test/test_primitives.cpp

@@ -652,7 +652,8 @@ int test_main()
 	TEST_CHECK(is_local(address::from_string("10.1.1.56", ec)));
 	TEST_CHECK(!is_local(address::from_string("14.14.251.63", ec)));
 	TEST_CHECK(is_loopback(address::from_string("127.0.0.1", ec)));
-	TEST_CHECK(is_loopback(address::from_string("::1", ec)));
+	if (supports_ipv6())
+		TEST_CHECK(is_loopback(address::from_string("::1", ec)));
 	TEST_CHECK(is_any(address_v6::any()));
 	TEST_CHECK(is_any(address_v4::any()));
 	TEST_CHECK(!is_any(address::from_string("31.53.21.64", ec)));