improved network interface enumeration and upnp device filtering

examples/enum_if.cpp

@@ -9,16 +9,19 @@ int main()
 {
 	io_service ios;
 	asio::error_code ec;
-	std::vector<address> const& net = enum_net_interfaces(ios, ec);
+	std::vector<ip_interface> const& net = enum_net_interfaces(ios, ec);
 
-	for (std::vector<address>::const_iterator i = net.begin()
+	for (std::vector<ip_interface>::const_iterator i = net.begin()
 		, end(net.end()); i != end; ++i)
 	{
-		std::cout << *i << " ";
-		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 << "address: " << i->interface_address << std::endl
+			<< "   mask: " << i->netmask << std::endl
+			<< "   flags: ";
+		if (is_multicast(i->interface_address)) std::cout << "multicast ";
+		if (is_local(i->interface_address)) std::cout << "local ";
+		if (is_loopback(i->interface_address)) std::cout << "loopback ";
+		std::cout << std::endl;
+		std::cout << "  router: " << router_for_interface(i->interface_address, ec);
 		std::cout << std::endl;
 	}
 

include/libtorrent/enum_net.hpp

@@ -37,7 +37,26 @@ POSSIBILITY OF SUCH DAMAGE.
 
 namespace libtorrent
 {
-	std::vector<address> enum_net_interfaces(asio::io_service& ios, asio::error_code& ec);
+
+	struct ip_interface
+	{
+		address interface_address;
+		address netmask;
+	};
+
+	// returns a list of the configured IP interfaces
+	// on the machine
+	std::vector<ip_interface> enum_net_interfaces(asio::io_service& ios
+		, asio::error_code& ec);
+
+	// returns true if the specified address is on the same
+	// local network as the specified interface
+	bool in_subnet(address const& addr, ip_interface const& iface);
+
+	// returns true if the specified address is on the same
+	// local network as us
+	bool in_local_network(asio::io_service& ios, address const& addr, asio::error_code& ec);
+	
 	address router_for_interface(address const interface, asio::error_code& ec);
 }
 

include/libtorrent/upnp.hpp

@@ -235,13 +235,12 @@ private:
 	
 	bool m_disabled;
 	bool m_closing;
+	bool m_ignore_outside_network;
 
 	connection_queue& m_cc;
 
 	std::string m_model;
 
-	std::vector<address> m_filter;
-
 #ifdef TORRENT_UPNP_LOGGING
 	std::ofstream m_log;
 #endif

src/broadcast_socket.cpp

@@ -79,12 +79,12 @@ namespace libtorrent
 	{
 		// 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);
+		std::vector<ip_interface> const& interfaces = enum_net_interfaces(ios, ec);
 		address ret = address_v4::any();
-		for (std::vector<address>::const_iterator i = interfaces.begin()
+		for (std::vector<ip_interface>::const_iterator i = interfaces.begin()
 			, end(interfaces.end()); i != end; ++i)
 		{
-			address const& a = *i;
+			address const& a = i->interface_address;
 			if (is_loopback(a)
 				|| is_multicast(a)
 				|| is_any(a)) continue;
@@ -111,28 +111,28 @@ namespace libtorrent
 		using namespace asio::ip::multicast;
 	
 		asio::error_code ec;
-		std::vector<address> interfaces = enum_net_interfaces(ios, ec);
+		std::vector<ip_interface> interfaces = enum_net_interfaces(ios, ec);
 
 		if (multicast_endpoint.address().is_v4())
 			open_multicast_socket(ios, address_v4::any(), loopback);
 		else
 			open_multicast_socket(ios, address_v6::any(), loopback);
 
-		for (std::vector<address>::const_iterator i = interfaces.begin()
+		for (std::vector<ip_interface>::const_iterator i = interfaces.begin()
 			, end(interfaces.end()); i != end; ++i)
 		{
 			// only broadcast to IPv4 addresses that are not local
-			if (!is_local(*i)) continue;
+			if (!is_local(i->interface_address)) continue;
 			// only multicast on compatible networks
-			if (i->is_v4() != multicast_endpoint.address().is_v4()) continue;
+			if (i->interface_address.is_v4() != multicast_endpoint.address().is_v4()) continue;
 			// ignore any loopback interface
-			if (is_loopback(*i)) continue;
+			if (is_loopback(i->interface_address)) continue;
 
 #ifndef NDEBUG
 //			std::cerr << "broadcast socket [ if: " << i->to_v4().to_string()
 //				<< " group: " << multicast_endpoint.address() << " ]" << std::endl;
 #endif
-			open_unicast_socket(ios, *i);
+			open_unicast_socket(ios, i->interface_address);
 		}
 	}
 

src/enum_net.cpp

@@ -30,7 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
-#if defined __linux__ || defined __MACH__
+#if defined __linux__ || defined BSD
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <net/if.h>
@@ -46,11 +46,58 @@ POSSIBILITY OF SUCH DAMAGE.
 
 namespace libtorrent
 {
-	std::vector<address> enum_net_interfaces(asio::io_service& ios, asio::error_code& ec)
+	namespace
 	{
-		std::vector<address> ret;
+		address sockaddr_to_address(sockaddr const* sin)
+		{
+			if (sin->sa_family == AF_INET)
+			{
+				typedef asio::ip::address_v4::bytes_type bytes_t;
+				bytes_t b;
+				memcpy(&b[0], &((sockaddr_in const*)sin)->sin_addr, b.size());
+				return address_v4(b);
+			}
+			else if (sin->sa_family == AF_INET6)
+			{
+				typedef asio::ip::address_v6::bytes_type bytes_t;
+				bytes_t b;
+				memcpy(&b[0], &((sockaddr_in6 const*)sin)->sin6_addr, b.size());
+				return address_v6(b);
+			}
+			return address();
+		}
+	}
+	
+	bool in_subnet(address const& addr, ip_interface const& iface)
+	{
+		if (addr.is_v4() != iface.interface_address.is_v4()) return false;
+		// since netmasks seems unreliable for IPv6 interfaces
+		// (MacOS X returns AF_INET addresses as bitmasks) assume
+		// that any IPv6 address belongs to the subnet of any
+		// interface with an IPv6 address
+		if (addr.is_v6()) return true;
 
-#if defined __linux__ || defined __MACH__ || defined(__FreeBSD__)
+		return (addr.to_v4().to_ulong() & iface.netmask.to_v4().to_ulong())
+			== (iface.interface_address.to_v4().to_ulong() & iface.netmask.to_v4().to_ulong());
+	}
+
+	bool in_local_network(asio::io_service& ios, address const& addr, asio::error_code& ec)
+	{
+		std::vector<ip_interface> const& net = enum_net_interfaces(ios, ec);
+		if (ec) return false;
+		for (std::vector<ip_interface>::const_iterator i = net.begin()
+			, end(net.end()); i != end; ++i)
+		{
+			if (in_subnet(addr, *i)) return true;
+		}
+		return false;
+	}
+	
+	std::vector<ip_interface> enum_net_interfaces(asio::io_service& ios, asio::error_code& ec)
+	{
+		std::vector<ip_interface> ret;
+
+#if defined __linux__ || defined BSD
 		int s = socket(AF_INET, SOCK_DGRAM, 0);
 		if (s < 0)
 		{
@@ -64,10 +111,9 @@ namespace libtorrent
 		if (ioctl(s, SIOCGIFCONF, &ifc) < 0)
 		{
 			close(s);
-			ec = asio::error::fault;
+			ec = asio::error_code(errno, asio::error::system_category);
 			return ret;
 		}
-		close(s);
 
 		char *ifr = (char*)ifc.ifc_req;
 		int remaining = ifc.ifc_len;
@@ -75,22 +121,25 @@ namespace libtorrent
 		while (remaining)
 		{
 			ifreq const& item = *reinterpret_cast<ifreq*>(ifr);
-			if (item.ifr_addr.sa_family == AF_INET)
+
+			if (item.ifr_addr.sa_family == AF_INET
+				|| item.ifr_addr.sa_family == AF_INET6)
 			{
-				typedef asio::ip::address_v4::bytes_type bytes_t;
-				bytes_t b;
-				memcpy(&b[0], &((sockaddr_in const*)&item.ifr_addr)->sin_addr, b.size());
-				ret.push_back(address_v4(b));
-			}
-			else if (item.ifr_addr.sa_family == AF_INET6)
-			{
-				typedef asio::ip::address_v6::bytes_type bytes_t;
-				bytes_t b;
-				memcpy(&b[0], &((sockaddr_in6 const*)&item.ifr_addr)->sin6_addr, b.size());
-				ret.push_back(address_v6(b));
+				ip_interface iface;
+				iface.interface_address = sockaddr_to_address(&item.ifr_addr);
+
+				ifreq netmask = item;
+				if (ioctl(s, SIOCGIFNETMASK, &netmask) < 0)
+				{
+					close(s);
+					ec = asio::error_code(errno, asio::error::system_category);
+					return ret;
+				}
+				iface.netmask = sockaddr_to_address(&netmask.ifr_addr);
+				ret.push_back(iface);
 			}
 
-#if defined __MACH__ || defined(__FreeBSD__)
+#if defined BSD
 			int current_size = item.ifr_addr.sa_len + IFNAMSIZ;
 #elif defined __linux__
 			int current_size = sizeof(ifreq);
@@ -98,6 +147,7 @@ namespace libtorrent
 			ifr += current_size;
 			remaining -= current_size;
 		}
+		close(s);
 
 #elif defined WIN32
 
@@ -122,21 +172,27 @@ namespace libtorrent
 
 		int n = size / sizeof(INTERFACE_INFO);
 
+		ip_interface iface;
 		for (int i = 0; i < n; ++i)
 		{
-			sockaddr_in *sockaddr = (sockaddr_in*)&buffer[i].iiAddress;
-			address a(address::from_string(inet_ntoa(sockaddr->sin_addr)));
-			if (a == address_v4::any()) continue;
-			ret.push_back(a);
+			iface.interface_address = sockaddr_to_address(&buffer[i].iiAddress.Address);
+			iface.netmask = sockaddr_to_address(&buffer[i].iiNetmask.Address);
+			if (iface.interface_address == address_v4::any()) continue;
+			ret.push_back(iface);
 		}
 
 #else
+#warning THIS OS IS NOT RECOGNIZED, enum_net_interfaces WILL PROBABLY NOT WORK
 		// 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"));
+		ip_interface iface;
 		for (;i != udp::resolver_iterator(); ++i)
 		{
-			ret.push_back(i->endpoint().address());
+			iface.interface_address = i->endpoint().address();
+			if (iface.interface_address.is_v4())
+				iface.netmask = iface.interface_address.to_v4().netmask();
+			ret.push_back(iface);
 		}
 #endif
 		return ret;

src/session_impl.cpp

@@ -959,12 +959,14 @@ namespace detail
 			{
 				// if we're listening on any IPv6 address, enumerate them and
 				// pick the first non-local address
-				std::vector<address> const& ifs = enum_net_interfaces(m_io_service, ec);
-				for (std::vector<address>::const_iterator i = ifs.begin()
+				std::vector<ip_interface> const& ifs = enum_net_interfaces(m_io_service, ec);
+				for (std::vector<ip_interface>::const_iterator i = ifs.begin()
 					, end(ifs.end()); i != end; ++i)
 				{
-					if (i->is_v4() || i->to_v6().is_link_local() || i->to_v6().is_loopback()) continue;
-					m_ipv6_interface = tcp::endpoint(*i, ep.port());
+					if (i->interface_address.is_v4()
+						|| i->interface_address.to_v6().is_link_local()
+						|| i->interface_address.to_v6().is_loopback()) continue;
+					m_ipv6_interface = tcp::endpoint(i->interface_address, ep.port());
 					break;
 				}
 				break;

src/upnp.cpp

@@ -75,27 +75,13 @@ upnp::upnp(io_service& ios, connection_queue& cc
 	, m_refresh_timer(ios)
 	, m_disabled(false)
 	, m_closing(false)
+	, m_ignore_outside_network(ignore_nonrouters)
 	, m_cc(cc)
 {
 #ifdef TORRENT_UPNP_LOGGING
 	m_log.open("upnp.log", std::ios::in | std::ios::out | std::ios::trunc);
 #endif
 	m_retry_count = 0;
-
-	if (ignore_nonrouters)
-	{
-		asio::error_code ec;
-		std::vector<address> const& net = enum_net_interfaces(m_io_service, ec);
-		m_filter.reserve(net.size());
-		for (std::vector<address>::const_iterator i = net.begin()
-			, end(net.end()); i != end; ++i)
-		{
-			asio::error_code e;
-			address a = router_for_interface(*i, e);
-			if (e || is_loopback(a)) continue;
-			m_filter.push_back(a);
-		}
-	}
 }
 
 upnp::~upnp()
@@ -264,14 +250,14 @@ void upnp::on_reply(udp::endpoint const& from, char* buffer
 	Server:Microsoft-Windows-NT/5.1 UPnP/1.0 UPnP-Device-Host/1.0
 
 */
-	if (!m_filter.empty() && std::find(m_filter.begin(), m_filter.end()
-		, from.address()) == m_filter.end())
+	asio::error_code ec;
+	if (m_ignore_outside_network && !in_local_network(m_io_service, from.address(), ec))
 	{
 		// this upnp device is filtered because it's not in the
 		// list of configured routers
 #ifdef TORRENT_UPNP_LOGGING
-		m_log << time_now_string() << " <== (" << from << ") Rootdevice "
-			"ignored because it's not out router" << std::endl;
+		m_log << time_now_string() << " <== (" << from << ") UPnP device "
+			"ignored because it's not on our network" << std::endl;
 #endif
 		return;
 	}