added router_for_interface along with a proper windows implementation. NAT-PMP support is now good on windows

examples/enum_if.cpp

@@ -18,7 +18,12 @@ int main()
 		if (is_multicast(*i)) std::cout << "multicast ";
 		if (is_local(*i)) std::cout << "local ";
 		if (is_loopback(*i)) std::cout << "loopback ";
+		std::cout << "router: " << router_for_interface(*i, ec);
 		std::cout << std::endl;
 	}
+
+	address local = guess_local_address(ios);
+
+	std::cout << "Local address: " << local << std::endl;
 }
 

include/libtorrent/broadcast_socket.hpp

@@ -46,7 +46,7 @@ namespace libtorrent
 	bool is_multicast(address const& addr);
 	bool is_any(address const& addr);
 
-	address_v4 guess_local_address(asio::io_service&);
+	address guess_local_address(asio::io_service&);
 
 	typedef boost::function<void(udp::endpoint const& from
 		, char* buffer, int size)> receive_handler_t;

include/libtorrent/enum_net.hpp

@@ -38,6 +38,7 @@ POSSIBILITY OF SUCH DAMAGE.
 namespace libtorrent
 {
 	std::vector<address> enum_net_interfaces(asio::io_service& ios, asio::error_code& ec);
+	address router_for_interface(address const interface, asio::error_code& ec);
 }
 
 #endif

src/broadcast_socket.cpp

@@ -51,23 +51,6 @@ namespace libtorrent
 			|| (ip & 0xffff0000) == 0xc0a80000);
 	}
 
-	address_v4 guess_local_address(asio::io_service& ios)
-	{
-		// make a best guess of the interface we're using and its IP
-		udp::resolver r(ios);
-		udp::resolver::iterator i = r.resolve(udp::resolver::query(asio::ip::host_name(), "0"));
-		for (;i != udp::resolver_iterator(); ++i)
-		{
-			address const& a = i->endpoint().address();
-			// ignore non-IPv4 addresses
-			if (!a.is_v4()) break;
-			// ignore the loopback
-			if (a.to_v4() == address_v4::loopback()) continue;
-		}
-		if (i == udp::resolver_iterator()) return address_v4::any();
-		return i->endpoint().address().to_v4();
-	}
-
 	bool is_loopback(address const& addr)
 	{
 		if (addr.is_v4())
@@ -92,6 +75,30 @@ namespace libtorrent
 			return addr.to_v6() == address_v6::any();
 	}
 
+	address guess_local_address(asio::io_service& ios)
+	{
+		// make a best guess of the interface we're using and its IP
+		asio::error_code ec;
+		std::vector<address> const& interfaces = enum_net_interfaces(ios, ec);
+		address ret = address_v4::any();
+		for (std::vector<address>::const_iterator i = interfaces.begin()
+			, end(interfaces.end()); i != end; ++i)
+		{
+			address const& a = *i;
+			if (is_loopback(a)
+				|| is_multicast(a)
+				|| is_any(a)) continue;
+
+			// prefer a v4 address, but return a v6 if
+			// there are no v4
+			if (a.is_v4()) return a;
+
+			if (ret != address_v4::any())
+				ret = a;
+		}
+		return ret;
+	}
+
 	broadcast_socket::broadcast_socket(asio::io_service& ios
 		, udp::endpoint const& multicast_endpoint
 		, receive_handler_t const& handler

src/enum_net.cpp

@@ -34,6 +34,12 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <net/if.h>
+#elif defined WIN32
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#include <iphlpapi.h>
 #endif
 
 #include "libtorrent/enum_net.hpp"
@@ -136,6 +142,77 @@ namespace libtorrent
 		return ret;
 	}
 
+	address router_for_interface(address const interface, asio::error_code& ec)
+	{
+#ifdef WIN32
+
+		// Load Iphlpapi library
+		HMODULE iphlp = LoadLibraryA("Iphlpapi.dll");
+		if (!iphlp)
+		{
+			ec = asio::error::fault;
+			return address_v4::any();
+		}
+
+		// Get GetAdaptersInfo() pointer
+		typedef DWORD (WINAPI *GetAdaptersInfo_t)(PIP_ADAPTER_INFO, PULONG);
+		GetAdaptersInfo_t GetAdaptersInfo = (GetAdaptersInfo_t)GetProcAddress(iphlp, "GetAdaptersInfo");
+		if (!GetAdaptersInfo)
+		{
+			FreeLibrary(iphlp);
+			ec = asio::error::fault;
+			return address_v4::any();
+		}
+
+		PIP_ADAPTER_INFO adapter_info = 0;
+		ULONG out_buf_size = 0;
+		if (GetAdaptersInfo(adapter_info, &out_buf_size) != ERROR_BUFFER_OVERFLOW)
+		{
+			FreeLibrary(iphlp);
+			ec = asio::error::fault;
+			return address_v4::any();
+		}
+
+		adapter_info = (IP_ADAPTER_INFO*)malloc(out_buf_size);
+		if (!adapter_info)
+		{
+			FreeLibrary(iphlp);
+			ec = asio::error::fault;
+			return address_v4::any();
+		}
+
+		address ret;
+		if (GetAdaptersInfo(adapter_info, &out_buf_size) == NO_ERROR)
+		{
+			PIP_ADAPTER_INFO adapter = adapter_info;
+			while (adapter != 0)
+			{
+				if (interface == address::from_string(adapter->IpAddressList.IpAddress.String, ec))
+				{
+					ret = address::from_string(adapter->GatewayList.IpAddress.String, ec);
+					break;
+				}
+				adapter = adapter->Next;
+			}
+		}
+   
+		// Free memory
+		free(adapter_info);
+		FreeLibrary(iphlp);
+
+		return ret;
+
+#else
+		// TODO: temporary implementation
+		if (!interface.is_v4())
+		{
+			ec = asio::error::fault;
+			return address_v4::any();
+		}
+		return address_v4((interface.to_v4().to_ulong() & 0xffffff00) | 1);
+#endif
+	}
+
 }
 
 

src/lsd.cpp

@@ -49,8 +49,8 @@ using namespace libtorrent;
 
 namespace libtorrent
 {
-	// defined in upnp.cpp
-	address_v4 guess_local_address(asio::io_service&);
+	// defined in broadcast_socket.cpp
+	address guess_local_address(asio::io_service&);
 }
 
 lsd::lsd(io_service& ios, address const& listen_interface

src/natpmp.cpp

@@ -38,6 +38,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/natpmp.hpp"
 #include "libtorrent/io.hpp"
 #include "libtorrent/assert.hpp"
+#include "libtorrent/enum_net.hpp"
 
 using boost::bind;
 using namespace libtorrent;
@@ -48,7 +49,7 @@ namespace libtorrent
 {
 	// defined in upnp.cpp
 	bool is_local(address const& a);
-	address_v4 guess_local_address(asio::io_service&);
+	address guess_local_address(asio::io_service&);
 }
 
 natpmp::natpmp(io_service& ios, address const& listen_interface, portmap_callback_t const& cb)
@@ -71,10 +72,10 @@ natpmp::natpmp(io_service& ios, address const& listen_interface, portmap_callbac
 
 void natpmp::rebind(address const& listen_interface) try
 {
-	address_v4 local = address_v4::any();
-	if (listen_interface.is_v4() && listen_interface != address_v4::any())
+	address local = address_v4::any();
+	if (listen_interface != address_v4::any())
 	{
-		local = listen_interface.to_v4();
+		local = listen_interface;
 	}
 	else
 	{
@@ -101,14 +102,12 @@ void natpmp::rebind(address const& listen_interface) try
 
 	m_disabled = false;
 
-	// assume the router is located on the local
-	// network as x.x.x.1
-	udp::endpoint nat_endpoint(
-		address_v4((local.to_ulong() & 0xffffff00) | 1), 5351);
+	asio::error_code ec;
+	udp::endpoint nat_endpoint(router_for_interface(local, ec), 5351);
+	if (ec)
+		throw std::runtime_error("cannot retrieve router address");
 
 	if (nat_endpoint == m_nat_endpoint) return;
-
-	// TODO: find a better way to figure out the router IP
 	m_nat_endpoint = nat_endpoint;
 
 #if defined(TORRENT_LOGGING) || defined(TORRENT_VERBOSE_LOGGING)

src/upnp.cpp

@@ -56,7 +56,7 @@ using namespace libtorrent;
 namespace libtorrent
 {
 	bool is_local(address const& a);
-	address_v4 guess_local_address(asio::io_service&);
+	address guess_local_address(asio::io_service&);
 }
 
 upnp::upnp(io_service& ios, connection_queue& cc