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socks.go
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socks.go
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package socks
import (
"errors"
"io"
"net"
"sync"
"time"
"github.com/v2ray/v2ray-core/app"
"github.com/v2ray/v2ray-core/common/alloc"
"github.com/v2ray/v2ray-core/common/log"
v2net "github.com/v2ray/v2ray-core/common/net"
"github.com/v2ray/v2ray-core/common/retry"
proxyerrors "github.com/v2ray/v2ray-core/proxy/common/errors"
jsonconfig "github.com/v2ray/v2ray-core/proxy/socks/config/json"
"github.com/v2ray/v2ray-core/proxy/socks/protocol"
)
var (
UnsupportedSocksCommand = errors.New("Unsupported socks command.")
UnsupportedAuthMethod = errors.New("Unsupported auth method.")
)
// SocksServer is a SOCKS 5 proxy server
type SocksServer struct {
accepting bool
dispatcher app.PacketDispatcher
config *jsonconfig.SocksConfig
}
func NewSocksServer(dispatcher app.PacketDispatcher, config *jsonconfig.SocksConfig) *SocksServer {
return &SocksServer{
dispatcher: dispatcher,
config: config,
}
}
func (server *SocksServer) Listen(port uint16) error {
listener, err := net.ListenTCP("tcp", &net.TCPAddr{
IP: []byte{0, 0, 0, 0},
Port: int(port),
Zone: "",
})
if err != nil {
log.Error("Socks failed to listen on port %d: %v", port, err)
return err
}
server.accepting = true
go server.AcceptConnections(listener)
if server.config.UDPEnabled {
server.ListenUDP(port)
}
return nil
}
func (server *SocksServer) AcceptConnections(listener *net.TCPListener) {
for server.accepting {
retry.Timed(100 /* times */, 100 /* ms */).On(func() error {
connection, err := listener.AcceptTCP()
if err != nil {
log.Error("Socks failed to accept new connection %v", err)
return err
}
go server.HandleConnection(connection)
return nil
})
}
}
func (server *SocksServer) HandleConnection(connection *net.TCPConn) error {
defer connection.Close()
reader := v2net.NewTimeOutReader(120, connection)
auth, auth4, err := protocol.ReadAuthentication(reader)
if err != nil && err != protocol.Socks4Downgrade {
log.Error("Socks failed to read authentication: %v", err)
return err
}
if err != nil && err == protocol.Socks4Downgrade {
return server.handleSocks4(reader, connection, auth4)
} else {
return server.handleSocks5(reader, connection, auth)
}
}
func (server *SocksServer) handleSocks5(reader *v2net.TimeOutReader, writer io.Writer, auth protocol.Socks5AuthenticationRequest) error {
expectedAuthMethod := protocol.AuthNotRequired
if server.config.IsPassword() {
expectedAuthMethod = protocol.AuthUserPass
}
if !auth.HasAuthMethod(expectedAuthMethod) {
authResponse := protocol.NewAuthenticationResponse(protocol.AuthNoMatchingMethod)
err := protocol.WriteAuthentication(writer, authResponse)
if err != nil {
log.Error("Socks failed to write authentication: %v", err)
return err
}
log.Warning("Socks client doesn't support allowed any auth methods.")
return UnsupportedAuthMethod
}
authResponse := protocol.NewAuthenticationResponse(expectedAuthMethod)
err := protocol.WriteAuthentication(writer, authResponse)
if err != nil {
log.Error("Socks failed to write authentication: %v", err)
return err
}
if server.config.IsPassword() {
upRequest, err := protocol.ReadUserPassRequest(reader)
if err != nil {
log.Error("Socks failed to read username and password: %v", err)
return err
}
status := byte(0)
if !server.config.HasAccount(upRequest.Username(), upRequest.Password()) {
status = byte(0xFF)
}
upResponse := protocol.NewSocks5UserPassResponse(status)
err = protocol.WriteUserPassResponse(writer, upResponse)
if err != nil {
log.Error("Socks failed to write user pass response: %v", err)
return err
}
if status != byte(0) {
log.Warning("Invalid user account: %s", upRequest.AuthDetail())
return proxyerrors.InvalidAuthentication
}
}
request, err := protocol.ReadRequest(reader)
if err != nil {
log.Error("Socks failed to read request: %v", err)
return err
}
if request.Command == protocol.CmdUdpAssociate && server.config.UDPEnabled {
return server.handleUDP(reader, writer)
}
if request.Command == protocol.CmdBind || request.Command == protocol.CmdUdpAssociate {
response := protocol.NewSocks5Response()
response.Error = protocol.ErrorCommandNotSupported
response.Port = uint16(0)
response.SetIPv4([]byte{0, 0, 0, 0})
responseBuffer := alloc.NewSmallBuffer().Clear()
response.Write(responseBuffer)
_, err = writer.Write(responseBuffer.Value)
responseBuffer.Release()
if err != nil {
log.Error("Socks failed to write response: %v", err)
return err
}
log.Warning("Unsupported socks command %d", request.Command)
return UnsupportedSocksCommand
}
response := protocol.NewSocks5Response()
response.Error = protocol.ErrorSuccess
// Some SOCKS software requires a value other than dest. Let's fake one:
response.Port = uint16(1717)
response.SetIPv4([]byte{0, 0, 0, 0})
responseBuffer := alloc.NewSmallBuffer().Clear()
response.Write(responseBuffer)
_, err = writer.Write(responseBuffer.Value)
responseBuffer.Release()
if err != nil {
log.Error("Socks failed to write response: %v", err)
return err
}
dest := request.Destination()
data, err := v2net.ReadFrom(reader, nil)
if err != nil {
return err
}
packet := v2net.NewPacket(dest, data, true)
server.transport(reader, writer, packet)
return nil
}
func (server *SocksServer) handleUDP(reader *v2net.TimeOutReader, writer io.Writer) error {
response := protocol.NewSocks5Response()
response.Error = protocol.ErrorSuccess
udpAddr := server.getUDPAddr()
response.Port = udpAddr.Port()
switch {
case udpAddr.IsIPv4():
response.SetIPv4(udpAddr.IP())
case udpAddr.IsIPv6():
response.SetIPv6(udpAddr.IP())
case udpAddr.IsDomain():
response.SetDomain(udpAddr.Domain())
}
responseBuffer := alloc.NewSmallBuffer().Clear()
response.Write(responseBuffer)
_, err := writer.Write(responseBuffer.Value)
responseBuffer.Release()
if err != nil {
log.Error("Socks failed to write response: %v", err)
return err
}
reader.SetTimeOut(300) /* 5 minutes */
v2net.ReadFrom(reader, nil) // Just in case of anything left in the socket
// The TCP connection closes after this method returns. We need to wait until
// the client closes it.
// TODO: get notified from UDP part
<-time.After(5 * time.Minute)
return nil
}
func (server *SocksServer) handleSocks4(reader io.Reader, writer io.Writer, auth protocol.Socks4AuthenticationRequest) error {
result := protocol.Socks4RequestGranted
if auth.Command == protocol.CmdBind {
result = protocol.Socks4RequestRejected
}
socks4Response := protocol.NewSocks4AuthenticationResponse(result, auth.Port, auth.IP[:])
responseBuffer := alloc.NewSmallBuffer().Clear()
socks4Response.Write(responseBuffer)
writer.Write(responseBuffer.Value)
responseBuffer.Release()
if result == protocol.Socks4RequestRejected {
log.Warning("Unsupported socks 4 command %d", auth.Command)
return UnsupportedSocksCommand
}
dest := v2net.NewTCPDestination(v2net.IPAddress(auth.IP[:], auth.Port))
data, err := v2net.ReadFrom(reader, nil)
if err != nil {
return err
}
packet := v2net.NewPacket(dest, data, true)
server.transport(reader, writer, packet)
return nil
}
func (server *SocksServer) transport(reader io.Reader, writer io.Writer, firstPacket v2net.Packet) {
ray := server.dispatcher.DispatchToOutbound(firstPacket)
input := ray.InboundInput()
output := ray.InboundOutput()
var inputFinish, outputFinish sync.Mutex
inputFinish.Lock()
outputFinish.Lock()
go dumpInput(reader, input, &inputFinish)
go dumpOutput(writer, output, &outputFinish)
outputFinish.Lock()
}
func dumpInput(reader io.Reader, input chan<- *alloc.Buffer, finish *sync.Mutex) {
v2net.ReaderToChan(input, reader)
finish.Unlock()
close(input)
}
func dumpOutput(writer io.Writer, output <-chan *alloc.Buffer, finish *sync.Mutex) {
v2net.ChanToWriter(writer, output)
finish.Unlock()
}