package dialer import ( "context" "errors" "fmt" "github.com/Dreamacro/clash/component/resolver" "net" "net/netip" "sync" ) var ( dialMux sync.Mutex actualSingleDialContext = singleDialContext actualDualStackDialContext = dualStackDialContext tcpConcurrent = false DisableIPv6 = false ) func DialContext(ctx context.Context, network, address string, options ...Option) (net.Conn, error) { opt := &option{ interfaceName: DefaultInterface.Load(), routingMark: int(DefaultRoutingMark.Load()), } for _, o := range DefaultOptions { o(opt) } for _, o := range options { o(opt) } switch network { case "tcp4", "tcp6", "udp4", "udp6": return actualSingleDialContext(ctx, network, address, opt) case "tcp", "udp": return actualDualStackDialContext(ctx, network, address, opt) default: return nil, errors.New("network invalid") } } func ListenPacket(ctx context.Context, network, address string, options ...Option) (net.PacketConn, error) { cfg := &option{ interfaceName: DefaultInterface.Load(), routingMark: int(DefaultRoutingMark.Load()), } for _, o := range DefaultOptions { o(cfg) } for _, o := range options { o(cfg) } if DisableIPv6 { network = "udp4" } lc := &net.ListenConfig{} if cfg.interfaceName != "" { addr, err := bindIfaceToListenConfig(cfg.interfaceName, lc, network, address) if err != nil { return nil, err } address = addr } if cfg.addrReuse { addrReuseToListenConfig(lc) } if cfg.routingMark != 0 { bindMarkToListenConfig(cfg.routingMark, lc, network, address) } return lc.ListenPacket(ctx, network, address) } func SetDial(concurrent bool) { dialMux.Lock() tcpConcurrent = concurrent if concurrent { actualSingleDialContext = concurrentSingleDialContext actualDualStackDialContext = concurrentDualStackDialContext } else { actualSingleDialContext = singleDialContext actualDualStackDialContext = dualStackDialContext } dialMux.Unlock() } func GetDial() bool { return tcpConcurrent } func dialContext(ctx context.Context, network string, destination netip.Addr, port string, opt *option) (net.Conn, error) { dialer := &net.Dialer{} if opt.interfaceName != "" { if err := bindIfaceToDialer(opt.interfaceName, dialer, network, destination); err != nil { return nil, err } } if opt.routingMark != 0 { bindMarkToDialer(opt.routingMark, dialer, network, destination) } if DisableIPv6 && destination.Is6() { return nil, fmt.Errorf("IPv6 is diabled, dialer cancel") } return dialer.DialContext(ctx, network, net.JoinHostPort(destination.String(), port)) } func dualStackDialContext(ctx context.Context, network, address string, opt *option) (net.Conn, error) { host, port, err := net.SplitHostPort(address) if err != nil { return nil, err } returned := make(chan struct{}) defer close(returned) type dialResult struct { net.Conn error resolved bool ipv6 bool done bool } results := make(chan dialResult) var primary, fallback dialResult startRacer := func(ctx context.Context, network, host string, direct bool, ipv6 bool) { result := dialResult{ipv6: ipv6, done: true} defer func() { select { case results <- result: case <-returned: if result.Conn != nil { _ = result.Conn.Close() } } }() var ip netip.Addr if ipv6 { if !direct { ip, result.error = resolver.ResolveIPv6ProxyServerHost(host) } else { ip, result.error = resolver.ResolveIPv6(host) } } else { if !direct { ip, result.error = resolver.ResolveIPv4ProxyServerHost(host) } else { ip, result.error = resolver.ResolveIPv4(host) } } if result.error != nil { return } result.resolved = true result.Conn, result.error = dialContext(ctx, network, ip, port, opt) } go startRacer(ctx, network+"4", host, opt.direct, false) go startRacer(ctx, network+"6", host, opt.direct, true) count := 2 for i := 0; i < count; i++ { select { case res := <-results: if res.error == nil { return res.Conn, nil } if !res.ipv6 { primary = res } else { fallback = res } if primary.done && fallback.done { if primary.resolved { return nil, primary.error } else if fallback.resolved { return nil, fallback.error } else { return nil, primary.error } } case <-ctx.Done(): break } } return nil, errors.New("dual stack tcp shake hands failed") } func concurrentDualStackDialContext(ctx context.Context, network, address string, opt *option) (net.Conn, error) { host, port, err := net.SplitHostPort(address) if err != nil { return nil, err } var ips []netip.Addr if opt.direct { ips, err = resolver.ResolveAllIP(host) } else { ips, err = resolver.ResolveAllIPProxyServerHost(host) } return concurrentDialContext(ctx, network, ips, port, opt) } func concurrentDialContext(ctx context.Context, network string, ips []netip.Addr, port string, opt *option) (net.Conn, error) { returned := make(chan struct{}) defer close(returned) type dialResult struct { ip netip.Addr net.Conn error resolved bool } results := make(chan dialResult) tcpRacer := func(ctx context.Context, ip netip.Addr) { result := dialResult{ip: ip} defer func() { select { case results <- result: case <-returned: if result.Conn != nil { result.Conn.Close() } } }() v := "4" if ip.Is6() { v = "6" } result.Conn, result.error = dialContext(ctx, network+v, ip, port, opt) } for _, ip := range ips { go tcpRacer(ctx, ip) } connCount := len(ips) for i := 0; i < connCount; i++ { select { case res := <-results: if res.error == nil { return res.Conn, nil } case <-ctx.Done(): break } } return nil, fmt.Errorf("all ips %v tcp shake hands failed", ips) } func singleDialContext(ctx context.Context, network string, address string, opt *option) (net.Conn, error) { host, port, err := net.SplitHostPort(address) if err != nil { return nil, err } var ip netip.Addr switch network { case "tcp4", "udp4": if !opt.direct { ip, err = resolver.ResolveIPv4ProxyServerHost(host) } else { ip, err = resolver.ResolveIPv4(host) } default: if !opt.direct { ip, err = resolver.ResolveIPv6ProxyServerHost(host) } else { ip, err = resolver.ResolveIPv6(host) } } if err != nil { return nil, err } return dialContext(ctx, network, ip, port, opt) } func concurrentSingleDialContext(ctx context.Context, network string, address string, opt *option) (net.Conn, error) { host, port, err := net.SplitHostPort(address) if err != nil { return nil, err } var ips []netip.Addr switch network { case "tcp4", "udp4": if !opt.direct { ips, err = resolver.ResolveAllIPv4ProxyServerHost(host) } else { ips, err = resolver.ResolveAllIPv4(host) } default: if !opt.direct { ips, err = resolver.ResolveAllIPv6ProxyServerHost(host) } else { ips, err = resolver.ResolveAllIPv6(host) } } if err != nil { return nil, err } return concurrentDialContext(ctx, network, ips, port, opt) }