refactor to use the utility function for bind_socket_to_device() instead of using the bind_to_device socket option directly, to make it best effort. include operation enum in udp_error alert.

include/libtorrent/alert_types.hpp

@@ -1326,6 +1326,7 @@ TORRENT_VERSION_NAMESPACE_2
 		udp_error_alert(
 			aux::stack_allocator& alloc
 			, udp::endpoint const& ep
+			, operation_t op
 			, error_code const& ec);
 
 		TORRENT_DEFINE_ALERT(udp_error_alert, 46)
@@ -1336,6 +1337,9 @@ TORRENT_VERSION_NAMESPACE_2
 		// the source address associated with the error (if any)
 		aux::noexcept_movable<udp::endpoint> endpoint;
 
+		// the operation that failed
+		operation_t operation;
+
 		// the error code describing the error
 		error_code const error;
 	};

include/libtorrent/enum_net.hpp

@@ -105,7 +105,7 @@ namespace libtorrent {
 	// TODO: 3 use string_view for device_name
 	template <class Socket>
 	address bind_socket_to_device(io_service& ios, Socket& sock
-		, boost::asio::ip::tcp const& protocol
+		, tcp const& protocol
 		, char const* device_name, int port, error_code& ec)
 	{
 		tcp::endpoint bind_ep(address_v4::any(), std::uint16_t(port));

src/alert.cpp

@@ -1018,15 +1018,19 @@ namespace {
 	udp_error_alert::udp_error_alert(
 		aux::stack_allocator&
 		, udp::endpoint const& ep
+		, operation_t op
 		, error_code const& ec)
 		: endpoint(ep)
+		, operation(op)
 		, error(ec)
 	{}
 
 	std::string udp_error_alert::message() const
 	{
 		error_code ec;
-		return "UDP error: " + convert_from_native(error.message()) + " from: " + endpoint.address().to_string(ec);
+		return "UDP error: " + convert_from_native(error.message())
+			+ " from: " + endpoint.address().to_string(ec)
+			+ " op: " + operation_name(operation);
 	}
 
 	external_ip_alert::external_ip_alert(aux::stack_allocator&

src/session_impl.cpp

@@ -1438,24 +1438,14 @@ namespace aux {
 				// have SO_BINDTODEVICE functionality, use it now.
 #if TORRENT_HAS_BINDTODEVICE
 				ret->sock->set_option(bind_to_device(lep.device.c_str()), ec);
-				if (ec)
-				{
 #ifndef TORRENT_DISABLE_LOGGING
-					if (should_log())
+				if (ec && should_log())
-					{
+				{
-						session_log("bind to device failed (device: %s): %s"
+					session_log("bind to device failed (device: %s): %s"
-							, lep.device.c_str(), ec.message().c_str());
+						, lep.device.c_str(), ec.message().c_str());
-					}
-#endif // TORRENT_DISABLE_LOGGING
-
-					last_op = operation_t::sock_bind_to_device;
-					if (m_alerts.should_post<listen_failed_alert>())
-					{
-						m_alerts.emplace_alert<listen_failed_alert>(lep.device, bind_ep
-							, last_op, ec, sock_type);
-					}
-					return ret;
 				}
+#endif // TORRENT_DISABLE_LOGGING
+				ec.clear();
 #endif
 			}
 
@@ -1589,24 +1579,14 @@ namespace aux {
 		if (!lep.device.empty())
 		{
 			ret->udp_sock->sock.set_option(bind_to_device(lep.device.c_str()), ec);
-			if (ec)
-			{
 #ifndef TORRENT_DISABLE_LOGGING
-				if (should_log())
+			if (ec && should_log())
-				{
+			{
-					session_log("bind to device failed (device: %s): %s"
+				session_log("bind to device failed (device: %s): %s"
-						, lep.device.c_str(), ec.message().c_str());
+					, lep.device.c_str(), ec.message().c_str());
-				}
-#endif // TORRENT_DISABLE_LOGGING
-
-				last_op = operation_t::sock_bind_to_device;
-				if (m_alerts.should_post<listen_failed_alert>())
-				{
-					m_alerts.emplace_alert<listen_failed_alert>(lep.device, bind_ep
-						, last_op, ec, udp_sock_type);
-				}
-				return ret;
 			}
+#endif // TORRENT_DISABLE_LOGGING
+			ec.clear();
 		}
 #endif
 		ret->udp_sock->sock.bind(udp_bind_ep, ec);
@@ -1676,7 +1656,8 @@ namespace aux {
 		if (err)
 		{
 			if (m_alerts.should_post<udp_error_alert>())
-				m_alerts.emplace_alert<udp_error_alert>(ret->udp_sock->sock.local_endpoint(ec), err);
+				m_alerts.emplace_alert<udp_error_alert>(ret->udp_sock->sock.local_endpoint(ec)
+					, operation_t::alloc_recvbuf, err);
 		}
 
 		ret->udp_sock->sock.set_force_proxy(m_settings.get_bool(settings_pack::force_proxy));
@@ -2042,7 +2023,8 @@ namespace aux {
 				}
 #endif
 				if (m_alerts.should_post<udp_error_alert>())
-					m_alerts.emplace_alert<udp_error_alert>(udp_bind_ep, ec);
+					m_alerts.emplace_alert<udp_error_alert>(udp_bind_ep
+						, operation_t::sock_open, ec);
 				continue;
 			}
 
@@ -2050,20 +2032,14 @@ namespace aux {
 			if (!ep.device.empty())
 			{
 				udp_sock->sock.set_option(bind_to_device(ep.device.c_str()), ec);
-				if (ec)
-				{
 #ifndef TORRENT_DISABLE_LOGGING
-					if (should_log())
+				if (ec && should_log())
-					{
+				{
-						session_log("bind to device failed (device: %s): %s"
+					session_log("bind to device failed (device: %s): %s"
-							, ep.device.c_str(), ec.message().c_str());
+						, ep.device.c_str(), ec.message().c_str());
-					}
-#endif // TORRENT_DISABLE_LOGGING
-
-					if (m_alerts.should_post<udp_error_alert>())
-						m_alerts.emplace_alert<udp_error_alert>(udp_bind_ep, ec);
-					continue;
 				}
+#endif // TORRENT_DISABLE_LOGGING
+				ec.clear();
 			}
 #endif
 			udp_sock->sock.bind(udp_bind_ep, ec);
@@ -2078,7 +2054,8 @@ namespace aux {
 				}
 #endif
 				if (m_alerts.should_post<udp_error_alert>())
-					m_alerts.emplace_alert<udp_error_alert>(udp_bind_ep, ec);
+					m_alerts.emplace_alert<udp_error_alert>(udp_bind_ep
+						, operation_t::sock_bind, ec);
 				continue;
 			}
 
@@ -2087,7 +2064,8 @@ namespace aux {
 			if (err)
 			{
 				if (m_alerts.should_post<udp_error_alert>())
-					m_alerts.emplace_alert<udp_error_alert>(udp_sock->sock.local_endpoint(ec), err);
+					m_alerts.emplace_alert<udp_error_alert>(udp_sock->sock.local_endpoint(ec)
+						, operation_t::alloc_recvbuf, err);
 			}
 
 			udp_sock->sock.set_force_proxy(m_settings.get_bool(settings_pack::force_proxy));
@@ -2370,7 +2348,8 @@ namespace aux {
 				&& ec != boost::asio::error::bad_descriptor
 				&& m_alerts.should_post<udp_error_alert>())
 			{
-				m_alerts.emplace_alert<udp_error_alert>(ep, ec);
+				m_alerts.emplace_alert<udp_error_alert>(ep
+					, operation_t::sock_read, ec);
 			}
 
 #ifndef TORRENT_DISABLE_LOGGING
@@ -2455,7 +2434,8 @@ namespace aux {
 
 				if (err != boost::asio::error::operation_aborted
 					&& m_alerts.should_post<udp_error_alert>())
-					m_alerts.emplace_alert<udp_error_alert>(ep, err);
+					m_alerts.emplace_alert<udp_error_alert>(ep
+						, operation_t::sock_read, err);
 
 #ifndef TORRENT_DISABLE_LOGGING
 				if (should_log())
@@ -5044,9 +5024,7 @@ namespace aux {
 			if (ec) return bind_ep;
 
 			bind_ep.address(bind_socket_to_device(m_io_service, s
-				, remote_address.is_v4()
+				, remote_address.is_v4() ? tcp::v4() : tcp::v6()
-					? boost::asio::ip::tcp::v4()
-					: boost::asio::ip::tcp::v6()
 				, ifname.c_str(), bind_ep.port(), ec));
 			return bind_ep;
 		}