mirror of
https://github.com/apernet/OpenGFW.git
synced 2024-11-14 14:29:22 +08:00
3022bde81b
Fixed: - "ineffective break statement. Did you mean to break out of the outer loop?" (SA4011) - "channels used with os/signal.Notify should be buffered" (SA1017) - "os.Kill cannot be trapped (did you mean syscall.SIGTERM?)" (SA1016) - "func envOrDefaultBool is unused" (U1000) - "should use time.Since instead of time.Now().Sub" (S1012)
509 lines
12 KiB
Go
509 lines
12 KiB
Go
package tcp
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import (
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"net"
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"github.com/apernet/OpenGFW/analyzer"
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"github.com/apernet/OpenGFW/analyzer/utils"
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)
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const (
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SocksInvalid = iota
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Socks4
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Socks4A
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Socks5
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Socks4Version = 0x04
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Socks5Version = 0x05
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Socks4ReplyVN = 0x00
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Socks4CmdTCPConnect = 0x01
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Socks4CmdTCPBind = 0x02
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Socks4ReqGranted = 0x5A
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Socks4ReqRejectOrFailed = 0x5B
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Socks4ReqRejectIdentd = 0x5C
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Socks4ReqRejectUser = 0x5D
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Socks5CmdTCPConnect = 0x01
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Socks5CmdTCPBind = 0x02
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Socks5CmdUDPAssociate = 0x03
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Socks5AuthNotRequired = 0x00
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Socks5AuthPassword = 0x02
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Socks5AuthNoMatchingMethod = 0xFF
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Socks5AuthSuccess = 0x00
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Socks5AuthFailure = 0x01
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Socks5AddrTypeIPv4 = 0x01
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Socks5AddrTypeDomain = 0x03
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Socks5AddrTypeIPv6 = 0x04
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)
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var _ analyzer.Analyzer = (*SocksAnalyzer)(nil)
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type SocksAnalyzer struct{}
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func (a *SocksAnalyzer) Name() string {
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return "socks"
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}
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func (a *SocksAnalyzer) Limit() int {
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// Socks4 length limit cannot be predicted
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return 0
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}
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func (a *SocksAnalyzer) NewTCP(info analyzer.TCPInfo, logger analyzer.Logger) analyzer.TCPStream {
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return newSocksStream(logger)
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}
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type socksStream struct {
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logger analyzer.Logger
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reqBuf *utils.ByteBuffer
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reqMap analyzer.PropMap
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reqUpdated bool
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reqLSM *utils.LinearStateMachine
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reqDone bool
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respBuf *utils.ByteBuffer
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respMap analyzer.PropMap
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respUpdated bool
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respLSM *utils.LinearStateMachine
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respDone bool
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version int
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authReqMethod int
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authUsername string
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authPassword string
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authRespMethod int
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}
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func newSocksStream(logger analyzer.Logger) *socksStream {
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s := &socksStream{logger: logger, reqBuf: &utils.ByteBuffer{}, respBuf: &utils.ByteBuffer{}}
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s.reqLSM = utils.NewLinearStateMachine(
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s.parseSocksReqVersion,
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)
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s.respLSM = utils.NewLinearStateMachine(
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s.parseSocksRespVersion,
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)
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return s
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}
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func (s *socksStream) Feed(rev, start, end bool, skip int, data []byte) (u *analyzer.PropUpdate, d bool) {
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if skip != 0 {
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return nil, true
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}
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if len(data) == 0 {
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return nil, false
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}
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var update *analyzer.PropUpdate
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var cancelled bool
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if rev {
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s.respBuf.Append(data)
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s.respUpdated = false
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cancelled, s.respDone = s.respLSM.Run()
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if s.respUpdated {
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update = &analyzer.PropUpdate{
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Type: analyzer.PropUpdateMerge,
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M: analyzer.PropMap{"resp": s.respMap},
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}
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s.respUpdated = false
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}
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} else {
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s.reqBuf.Append(data)
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s.reqUpdated = false
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cancelled, s.reqDone = s.reqLSM.Run()
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if s.reqUpdated {
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update = &analyzer.PropUpdate{
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Type: analyzer.PropUpdateMerge,
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M: analyzer.PropMap{
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"version": s.socksVersion(),
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"req": s.reqMap,
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},
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}
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s.reqUpdated = false
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}
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}
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return update, cancelled || (s.reqDone && s.respDone)
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}
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func (s *socksStream) Close(limited bool) *analyzer.PropUpdate {
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s.reqBuf.Reset()
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s.respBuf.Reset()
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s.reqMap = nil
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s.respMap = nil
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return nil
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}
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func (s *socksStream) parseSocksReqVersion() utils.LSMAction {
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socksVer, ok := s.reqBuf.GetByte(true)
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if !ok {
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return utils.LSMActionPause
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}
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if socksVer != Socks4Version && socksVer != Socks5Version {
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return utils.LSMActionCancel
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}
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s.reqMap = make(analyzer.PropMap)
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s.reqUpdated = true
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if socksVer == Socks4Version {
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s.version = Socks4
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s.reqLSM.AppendSteps(
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s.parseSocks4ReqIpAndPort,
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s.parseSocks4ReqUserId,
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s.parseSocks4ReqHostname,
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)
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} else {
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s.version = Socks5
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s.reqLSM.AppendSteps(
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s.parseSocks5ReqMethod,
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s.parseSocks5ReqAuth,
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s.parseSocks5ReqConnInfo,
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)
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}
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocksRespVersion() utils.LSMAction {
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socksVer, ok := s.respBuf.GetByte(true)
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if !ok {
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return utils.LSMActionPause
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}
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if (s.version == Socks4 || s.version == Socks4A) && socksVer != Socks4ReplyVN ||
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s.version == Socks5 && socksVer != Socks5Version || s.version == SocksInvalid {
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return utils.LSMActionCancel
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}
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if socksVer == Socks4ReplyVN {
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s.respLSM.AppendSteps(
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s.parseSocks4RespPacket,
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)
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} else {
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s.respLSM.AppendSteps(
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s.parseSocks5RespMethod,
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s.parseSocks5RespAuth,
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s.parseSocks5RespConnInfo,
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)
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}
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5ReqMethod() utils.LSMAction {
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nMethods, ok := s.reqBuf.GetByte(false)
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if !ok {
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return utils.LSMActionPause
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}
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methods, ok := s.reqBuf.Get(int(nMethods)+1, true)
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if !ok {
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return utils.LSMActionPause
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}
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// For convenience, we only take the first method we can process
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s.authReqMethod = Socks5AuthNoMatchingMethod
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for _, method := range methods[1:] {
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switch method {
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case Socks5AuthNotRequired:
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s.authReqMethod = Socks5AuthNotRequired
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return utils.LSMActionNext
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case Socks5AuthPassword:
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s.authReqMethod = Socks5AuthPassword
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return utils.LSMActionNext
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default:
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// TODO: more auth method to support
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}
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}
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5ReqAuth() utils.LSMAction {
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switch s.authReqMethod {
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case Socks5AuthNotRequired:
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s.reqMap["auth"] = analyzer.PropMap{"method": s.authReqMethod}
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case Socks5AuthPassword:
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meta, ok := s.reqBuf.Get(2, false)
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if !ok {
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return utils.LSMActionPause
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}
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if meta[0] != 0x01 {
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return utils.LSMActionCancel
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}
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usernameLen := int(meta[1])
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meta, ok = s.reqBuf.Get(usernameLen+3, false)
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if !ok {
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return utils.LSMActionPause
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}
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passwordLen := int(meta[usernameLen+2])
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meta, ok = s.reqBuf.Get(usernameLen+passwordLen+3, true)
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if !ok {
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return utils.LSMActionPause
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}
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s.authUsername = string(meta[2 : usernameLen+2])
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s.authPassword = string(meta[usernameLen+3:])
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s.reqMap["auth"] = analyzer.PropMap{
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"method": s.authReqMethod,
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"username": s.authUsername,
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"password": s.authPassword,
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}
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default:
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return utils.LSMActionCancel
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}
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s.reqUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5ReqConnInfo() utils.LSMAction {
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/* preInfo struct
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+----+-----+-------+------+-------------+
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|VER | CMD | RSV | ATYP | DST.ADDR(1) |
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+----+-----+-------+------+-------------+
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*/
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preInfo, ok := s.reqBuf.Get(5, false)
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if !ok {
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return utils.LSMActionPause
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}
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// verify socks version
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if preInfo[0] != Socks5Version {
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return utils.LSMActionCancel
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}
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var pktLen int
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switch int(preInfo[3]) {
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case Socks5AddrTypeIPv4:
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pktLen = 10
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case Socks5AddrTypeDomain:
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domainLen := int(preInfo[4])
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pktLen = 7 + domainLen
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case Socks5AddrTypeIPv6:
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pktLen = 22
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default:
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return utils.LSMActionCancel
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}
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pkt, ok := s.reqBuf.Get(pktLen, true)
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if !ok {
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return utils.LSMActionPause
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}
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// parse cmd
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cmd := int(pkt[1])
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if cmd != Socks5CmdTCPConnect && cmd != Socks5CmdTCPBind && cmd != Socks5CmdUDPAssociate {
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return utils.LSMActionCancel
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}
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s.reqMap["cmd"] = cmd
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// parse addr type
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addrType := int(pkt[3])
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var addr string
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switch addrType {
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case Socks5AddrTypeIPv4:
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addr = net.IPv4(pkt[4], pkt[5], pkt[6], pkt[7]).String()
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case Socks5AddrTypeDomain:
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addr = string(pkt[5 : 5+pkt[4]])
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case Socks5AddrTypeIPv6:
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addr = net.IP(pkt[4 : 4+net.IPv6len]).String()
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default:
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return utils.LSMActionCancel
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}
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s.reqMap["addr_type"] = addrType
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s.reqMap["addr"] = addr
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// parse port
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port := int(pkt[pktLen-2])<<8 | int(pkt[pktLen-1])
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s.reqMap["port"] = port
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s.reqUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5RespMethod() utils.LSMAction {
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method, ok := s.respBuf.Get(1, true)
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if !ok {
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return utils.LSMActionPause
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}
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s.authRespMethod = int(method[0])
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s.respMap = make(analyzer.PropMap)
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5RespAuth() utils.LSMAction {
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switch s.authRespMethod {
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case Socks5AuthNotRequired:
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s.respMap["auth"] = analyzer.PropMap{"method": s.authRespMethod}
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case Socks5AuthPassword:
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authResp, ok := s.respBuf.Get(2, true)
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if !ok {
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return utils.LSMActionPause
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}
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if authResp[0] != 0x01 {
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return utils.LSMActionCancel
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}
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authStatus := int(authResp[1])
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s.respMap["auth"] = analyzer.PropMap{
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"method": s.authRespMethod,
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"status": authStatus,
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}
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default:
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return utils.LSMActionCancel
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}
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s.respUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks5RespConnInfo() utils.LSMAction {
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/* preInfo struct
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+----+-----+-------+------+-------------+
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|VER | REP | RSV | ATYP | BND.ADDR(1) |
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+----+-----+-------+------+-------------+
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*/
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preInfo, ok := s.respBuf.Get(5, false)
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if !ok {
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return utils.LSMActionPause
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}
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// verify socks version
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if preInfo[0] != Socks5Version {
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return utils.LSMActionCancel
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}
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var pktLen int
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switch int(preInfo[3]) {
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case Socks5AddrTypeIPv4:
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pktLen = 10
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case Socks5AddrTypeDomain:
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domainLen := int(preInfo[4])
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pktLen = 7 + domainLen
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case Socks5AddrTypeIPv6:
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pktLen = 22
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default:
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return utils.LSMActionCancel
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}
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pkt, ok := s.respBuf.Get(pktLen, true)
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if !ok {
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return utils.LSMActionPause
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}
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// parse rep
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rep := int(pkt[1])
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s.respMap["rep"] = rep
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// parse addr type
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addrType := int(pkt[3])
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var addr string
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switch addrType {
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case Socks5AddrTypeIPv4:
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addr = net.IPv4(pkt[4], pkt[5], pkt[6], pkt[7]).String()
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case Socks5AddrTypeDomain:
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addr = string(pkt[5 : 5+pkt[4]])
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case Socks5AddrTypeIPv6:
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addr = net.IP(pkt[4 : 4+net.IPv6len]).String()
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default:
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return utils.LSMActionCancel
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}
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s.respMap["addr_type"] = addrType
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s.respMap["addr"] = addr
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// parse port
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port := int(pkt[pktLen-2])<<8 | int(pkt[pktLen-1])
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s.respMap["port"] = port
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s.respUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks4ReqIpAndPort() utils.LSMAction {
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/* Following field will be parsed in this state:
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+-----+----------+--------+
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| CMD | DST.PORT | DST.IP |
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+-----+----------+--------+
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*/
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pkt, ok := s.reqBuf.Get(7, true)
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if !ok {
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return utils.LSMActionPause
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}
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if pkt[0] != Socks4CmdTCPConnect && pkt[0] != Socks4CmdTCPBind {
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return utils.LSMActionCancel
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}
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dstPort := uint16(pkt[1])<<8 | uint16(pkt[2])
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dstIp := net.IPv4(pkt[3], pkt[4], pkt[5], pkt[6]).String()
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// Socks4a extension
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if pkt[3] == 0 && pkt[4] == 0 && pkt[5] == 0 {
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s.version = Socks4A
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}
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s.reqMap["cmd"] = pkt[0]
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s.reqMap["addr"] = dstIp
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s.reqMap["addr_type"] = Socks5AddrTypeIPv4
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s.reqMap["port"] = dstPort
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s.reqUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks4ReqUserId() utils.LSMAction {
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userIdSlice, ok := s.reqBuf.GetUntil([]byte("\x00"), true, true)
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if !ok {
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return utils.LSMActionPause
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}
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userId := string(userIdSlice[:len(userIdSlice)-1])
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s.reqMap["auth"] = analyzer.PropMap{
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"user_id": userId,
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}
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s.reqUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks4ReqHostname() utils.LSMAction {
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// Only Socks4a support hostname
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if s.version != Socks4A {
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return utils.LSMActionNext
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}
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hostnameSlice, ok := s.reqBuf.GetUntil([]byte("\x00"), true, true)
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if !ok {
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return utils.LSMActionPause
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}
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hostname := string(hostnameSlice[:len(hostnameSlice)-1])
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s.reqMap["addr"] = hostname
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s.reqMap["addr_type"] = Socks5AddrTypeDomain
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s.reqUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) parseSocks4RespPacket() utils.LSMAction {
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pkt, ok := s.respBuf.Get(7, true)
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if !ok {
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return utils.LSMActionPause
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}
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if pkt[0] != Socks4ReqGranted &&
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pkt[0] != Socks4ReqRejectOrFailed &&
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pkt[0] != Socks4ReqRejectIdentd &&
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pkt[0] != Socks4ReqRejectUser {
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return utils.LSMActionCancel
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}
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dstPort := uint16(pkt[1])<<8 | uint16(pkt[2])
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dstIp := net.IPv4(pkt[3], pkt[4], pkt[5], pkt[6]).String()
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s.respMap = analyzer.PropMap{
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"rep": pkt[0],
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"addr": dstIp,
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"addr_type": Socks5AddrTypeIPv4,
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"port": dstPort,
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}
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s.respUpdated = true
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return utils.LSMActionNext
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}
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func (s *socksStream) socksVersion() int {
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switch s.version {
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case Socks4, Socks4A:
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return Socks4Version
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case Socks5:
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return Socks5Version
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default:
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return SocksInvalid
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}
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}
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