package internet import ( "context" "github.com/xtls/xray-core/common" "github.com/xtls/xray-core/common/dice" "github.com/xtls/xray-core/common/net" "github.com/xtls/xray-core/common/net/cnc" "github.com/xtls/xray-core/common/session" "github.com/xtls/xray-core/features/dns" "github.com/xtls/xray-core/features/outbound" "github.com/xtls/xray-core/transport" "github.com/xtls/xray-core/transport/internet/stat" "github.com/xtls/xray-core/transport/pipe" ) // Dialer is the interface for dialing outbound connections. type Dialer interface { // Dial dials a system connection to the given destination. Dial(ctx context.Context, destination net.Destination) (stat.Connection, error) // Address returns the address used by this Dialer. Maybe nil if not known. Address() net.Address } // dialFunc is an interface to dial network connection to a specific destination. type dialFunc func(ctx context.Context, dest net.Destination, streamSettings *MemoryStreamConfig) (stat.Connection, error) var transportDialerCache = make(map[string]dialFunc) // RegisterTransportDialer registers a Dialer with given name. func RegisterTransportDialer(protocol string, dialer dialFunc) error { if _, found := transportDialerCache[protocol]; found { return newError(protocol, " dialer already registered").AtError() } transportDialerCache[protocol] = dialer return nil } // Dial dials a internet connection towards the given destination. func Dial(ctx context.Context, dest net.Destination, streamSettings *MemoryStreamConfig) (stat.Connection, error) { if dest.Network == net.Network_TCP { if streamSettings == nil { s, err := ToMemoryStreamConfig(nil) if err != nil { return nil, newError("failed to create default stream settings").Base(err) } streamSettings = s } protocol := streamSettings.ProtocolName dialer := transportDialerCache[protocol] if dialer == nil { return nil, newError(protocol, " dialer not registered").AtError() } return dialer(ctx, dest, streamSettings) } if dest.Network == net.Network_UDP { udpDialer := transportDialerCache["udp"] if udpDialer == nil { return nil, newError("UDP dialer not registered").AtError() } return udpDialer(ctx, dest, streamSettings) } return nil, newError("unknown network ", dest.Network) } var ( dnsClient dns.Client obm outbound.Manager ) func lookupIP(domain string, strategy DomainStrategy, localAddr net.Address) ([]net.IP, error) { if dnsClient == nil { return nil, nil } ips, err := dnsClient.LookupIP(domain, dns.IPOption{ IPv4Enable: (localAddr == nil || localAddr.Family().IsIPv4()) && strategy.preferIP4(), IPv6Enable: (localAddr == nil || localAddr.Family().IsIPv6()) && strategy.preferIP6(), }) { // Resolve fallback if (len(ips) == 0 || err != nil) && strategy.hasFallback() && localAddr == nil { ips, err = dnsClient.LookupIP(domain, dns.IPOption{ IPv4Enable: strategy.fallbackIP4(), IPv6Enable: strategy.fallbackIP6(), }) } } return ips, err } func canLookupIP(ctx context.Context, dst net.Destination, sockopt *SocketConfig) bool { if dst.Address.Family().IsIP() || dnsClient == nil { return false } return sockopt.DomainStrategy.hasStrategy() } func redirect(ctx context.Context, dst net.Destination, obt string) net.Conn { newError("redirecting request " + dst.String() + " to " + obt).WriteToLog(session.ExportIDToError(ctx)) h := obm.GetHandler(obt) ctx = session.ContextWithOutbound(ctx, &session.Outbound{Target: dst, Gateway: nil}) if h != nil { ur, uw := pipe.New(pipe.OptionsFromContext(ctx)...) dr, dw := pipe.New(pipe.OptionsFromContext(ctx)...) go h.Dispatch(ctx, &transport.Link{Reader: ur, Writer: dw}) nc := cnc.NewConnection( cnc.ConnectionInputMulti(uw), cnc.ConnectionOutputMulti(dr), cnc.ConnectionOnClose(common.ChainedClosable{uw, dw}), ) return nc } return nil } // DialSystem calls system dialer to create a network connection. func DialSystem(ctx context.Context, dest net.Destination, sockopt *SocketConfig) (net.Conn, error) { var src net.Address if outbound := session.OutboundFromContext(ctx); outbound != nil { src = outbound.Gateway } if sockopt == nil { return effectiveSystemDialer.Dial(ctx, src, dest, sockopt) } if canLookupIP(ctx, dest, sockopt) { ips, err := lookupIP(dest.Address.String(), sockopt.DomainStrategy, src) if err == nil && len(ips) > 0 { dest.Address = net.IPAddress(ips[dice.Roll(len(ips))]) newError("replace destination with " + dest.String()).AtInfo().WriteToLog() } else if err != nil { newError("failed to resolve ip").Base(err).AtWarning().WriteToLog() } } if obm != nil && len(sockopt.DialerProxy) > 0 { nc := redirect(ctx, dest, sockopt.DialerProxy) if nc != nil { return nc, nil } } return effectiveSystemDialer.Dial(ctx, src, dest, sockopt) } func InitSystemDialer(dc dns.Client, om outbound.Manager) { dnsClient = dc obm = om }