github.com/v2fly/v2ray-core/v5@v5.16.2-0.20240507031116-8191faa6e095/transport/internet/dialer.go (about)

     1  package internet
     2  
     3  import (
     4  	"context"
     5  
     6  	"github.com/v2fly/v2ray-core/v5/common/net"
     7  	"github.com/v2fly/v2ray-core/v5/common/session"
     8  	"github.com/v2fly/v2ray-core/v5/transport/internet/tagged"
     9  )
    10  
    11  // Dialer is the interface for dialing outbound connections.
    12  type Dialer interface {
    13  	// Dial dials a system connection to the given destination.
    14  	Dial(ctx context.Context, destination net.Destination) (Connection, error)
    15  
    16  	// Address returns the address used by this Dialer. Maybe nil if not known.
    17  	Address() net.Address
    18  }
    19  
    20  // dialFunc is an interface to dial network connection to a specific destination.
    21  type dialFunc func(ctx context.Context, dest net.Destination, streamSettings *MemoryStreamConfig) (Connection, error)
    22  
    23  var transportDialerCache = make(map[string]dialFunc)
    24  
    25  // RegisterTransportDialer registers a Dialer with given name.
    26  func RegisterTransportDialer(protocol string, dialer dialFunc) error {
    27  	if _, found := transportDialerCache[protocol]; found {
    28  		return newError(protocol, " dialer already registered").AtError()
    29  	}
    30  	transportDialerCache[protocol] = dialer
    31  	return nil
    32  }
    33  
    34  // Dial dials a internet connection towards the given destination.
    35  func Dial(ctx context.Context, dest net.Destination, streamSettings *MemoryStreamConfig) (Connection, error) {
    36  	if dest.Network == net.Network_TCP {
    37  		if streamSettings == nil {
    38  			s, err := ToMemoryStreamConfig(nil)
    39  			if err != nil {
    40  				return nil, newError("failed to create default stream settings").Base(err)
    41  			}
    42  			streamSettings = s
    43  		}
    44  
    45  		protocol := streamSettings.ProtocolName
    46  
    47  		if originalProtocolName := getOriginalMessageName(streamSettings); originalProtocolName != "" {
    48  			protocol = originalProtocolName
    49  		}
    50  
    51  		dialer := transportDialerCache[protocol]
    52  		if dialer == nil {
    53  			return nil, newError(protocol, " dialer not registered").AtError()
    54  		}
    55  		return dialer(ctx, dest, streamSettings)
    56  	}
    57  
    58  	if dest.Network == net.Network_UDP {
    59  		udpDialer := transportDialerCache["udp"]
    60  		if udpDialer == nil {
    61  			return nil, newError("UDP dialer not registered").AtError()
    62  		}
    63  		return udpDialer(ctx, dest, streamSettings)
    64  	}
    65  
    66  	return nil, newError("unknown network ", dest.Network)
    67  }
    68  
    69  // DialSystem calls system dialer to create a network connection.
    70  func DialSystem(ctx context.Context, dest net.Destination, sockopt *SocketConfig) (net.Conn, error) {
    71  	outbound := session.OutboundFromContext(ctx)
    72  
    73  	var src net.Address
    74  	if outbound != nil {
    75  		src = outbound.Gateway
    76  	}
    77  
    78  	if transportLayerOutgoingTag := session.GetTransportLayerProxyTagFromContext(ctx); transportLayerOutgoingTag != "" {
    79  		return DialTaggedOutbound(ctx, dest, transportLayerOutgoingTag)
    80  	}
    81  
    82  	originalAddr := dest.Address
    83  	if outbound != nil && outbound.Resolver != nil && dest.Address.Family().IsDomain() {
    84  		if addr := outbound.Resolver(ctx, dest.Address.Domain()); addr != nil {
    85  			dest.Address = addr
    86  		}
    87  	}
    88  
    89  	switch {
    90  	case src != nil && dest.Address != originalAddr:
    91  		newError("dialing to ", dest, " resolved from ", originalAddr, " via ", src).WriteToLog(session.ExportIDToError(ctx))
    92  	case src != nil:
    93  		newError("dialing to ", dest, " via ", src).WriteToLog(session.ExportIDToError(ctx))
    94  	case dest.Address != originalAddr:
    95  		newError("dialing to ", dest, " resolved from ", originalAddr).WriteToLog(session.ExportIDToError(ctx))
    96  	}
    97  
    98  	return effectiveSystemDialer.Dial(ctx, src, dest, sockopt)
    99  }
   100  
   101  func DialTaggedOutbound(ctx context.Context, dest net.Destination, tag string) (net.Conn, error) {
   102  	if tagged.Dialer == nil {
   103  		return nil, newError("tagged dial not enabled")
   104  	}
   105  	return tagged.Dialer(ctx, dest, tag)
   106  }