122 lines
2.7 KiB
Go
122 lines
2.7 KiB
Go
package socks5
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import (
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"fmt"
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"net"
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"strconv"
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)
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const (
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// protocol version
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socks4Version = uint8(4)
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socks5Version = uint8(5)
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// request command
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ConnectCommand = uint8(1)
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BindCommand = uint8(2)
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AssociateCommand = uint8(3) // udp associate
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// address type
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ipv4Address = uint8(1)
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fqdnAddress = uint8(3) // domain
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ipv6Address = uint8(4)
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)
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//
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const (
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successReply uint8 = iota
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serverFailure
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ruleFailure
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networkUnreachable
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hostUnreachable
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connectionRefused
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ttlExpired
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commandNotSupported
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addrTypeNotSupported
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// 0x09 - 0xff unassigned
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)
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// head len defined
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const (
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// common fields
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reqProtocolVersionBytePos = uint8(0) // proto version pos
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reqCommandBytePos = uint8(1)
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reqAddrBytePos = uint8(4)
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reqStartLen = uint8(4)
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headVERLen = 1
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headCMDLen = 1
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headRSVLen = 1
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headATYPLen = 1
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headPORTLen = 2
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headFQDNAddrLen = 1
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reqFQDNAddr = 249
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)
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// AddrSpec is used to return the target AddrSpec
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// which may be specified as IPv4, IPv6, or a FQDN
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type AddrSpec struct {
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FQDN string
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IP net.IP
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Port int
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}
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func (a *AddrSpec) String() string {
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if a.FQDN != "" {
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return fmt.Sprintf("%s (%s):%d", a.FQDN, a.IP, a.Port)
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}
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return fmt.Sprintf("%s:%d", a.IP, a.Port)
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}
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// Address returns a string suitable to dial; prefer returning IP-based
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// address, fallback to FQDN
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func (a AddrSpec) Address() string {
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if 0 != len(a.IP) {
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return net.JoinHostPort(a.IP.String(), strconv.Itoa(a.Port))
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}
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return net.JoinHostPort(a.FQDN, strconv.Itoa(a.Port))
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}
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// Header represents the SOCKS5/SOCKS4 header, it contains everything that is not payload
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type Header struct {
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// Version of socks protocol for message
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Version uint8
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// Socks Command "connect","bind","associate"
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Command uint8
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// Reserved byte
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Reserved uint8 // only socks5 support
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// Address in socks message
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Address AddrSpec
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// private stuff set when Header parsed
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addrType uint8
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}
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func (h Header) Bytes() (b []byte) {
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b = append(b, h.Version)
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b = append(b, h.Command)
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hiPort, loPort := breakPort(h.Address.Port)
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if h.Version == socks4Version {
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b = append(b, hiPort, loPort)
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b = append(b, h.Address.IP...)
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} else if h.Version == socks5Version {
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b = append(b, h.Reserved)
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b = append(b, h.addrType)
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if h.addrType == fqdnAddress {
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b = append(b, byte(len(h.Address.FQDN)))
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b = append(b, []byte(h.Address.FQDN)...)
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} else if h.addrType == ipv4Address {
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b = append(b, h.Address.IP.To4()...)
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} else if h.addrType == ipv6Address {
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b = append(b, h.Address.IP.To16()...)
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}
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b = append(b, hiPort, loPort)
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}
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return b
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}
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func buildPort(hi, lo byte) int {
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return (int(hi) << 8) | int(lo)
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}
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func breakPort(port int) (hi, lo byte) {
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return byte(port >> 8), byte(port)
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}
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