431 lines
9.7 KiB
Go
431 lines
9.7 KiB
Go
package socks5
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"errors"
|
|
"io"
|
|
"net"
|
|
"strconv"
|
|
|
|
"github.com/Dreamacro/clash/component/auth"
|
|
)
|
|
|
|
// Error represents a SOCKS error
|
|
type Error byte
|
|
|
|
func (err Error) Error() string {
|
|
return "SOCKS error: " + strconv.Itoa(int(err))
|
|
}
|
|
|
|
// Command is request commands as defined in RFC 1928 section 4.
|
|
type Command = uint8
|
|
|
|
const Version = 5
|
|
|
|
// SOCKS request commands as defined in RFC 1928 section 4.
|
|
const (
|
|
CmdConnect Command = 1
|
|
CmdBind Command = 2
|
|
CmdUDPAssociate Command = 3
|
|
)
|
|
|
|
// SOCKS address types as defined in RFC 1928 section 5.
|
|
const (
|
|
AtypIPv4 = 1
|
|
AtypDomainName = 3
|
|
AtypIPv6 = 4
|
|
)
|
|
|
|
// MaxAddrLen is the maximum size of SOCKS address in bytes.
|
|
const MaxAddrLen = 1 + 1 + 255 + 2
|
|
|
|
// MaxAuthLen is the maximum size of user/password field in SOCKS5 Auth
|
|
const MaxAuthLen = 255
|
|
|
|
// Addr represents a SOCKS address as defined in RFC 1928 section 5.
|
|
type Addr []byte
|
|
|
|
func (a Addr) String() string {
|
|
var host, port string
|
|
|
|
switch a[0] {
|
|
case AtypDomainName:
|
|
hostLen := uint16(a[1])
|
|
host = string(a[2 : 2+hostLen])
|
|
port = strconv.Itoa((int(a[2+hostLen]) << 8) | int(a[2+hostLen+1]))
|
|
case AtypIPv4:
|
|
host = net.IP(a[1 : 1+net.IPv4len]).String()
|
|
port = strconv.Itoa((int(a[1+net.IPv4len]) << 8) | int(a[1+net.IPv4len+1]))
|
|
case AtypIPv6:
|
|
host = net.IP(a[1 : 1+net.IPv6len]).String()
|
|
port = strconv.Itoa((int(a[1+net.IPv6len]) << 8) | int(a[1+net.IPv6len+1]))
|
|
}
|
|
|
|
return net.JoinHostPort(host, port)
|
|
}
|
|
|
|
// UDPAddr converts a socks5.Addr to *net.UDPAddr
|
|
func (a Addr) UDPAddr() *net.UDPAddr {
|
|
if len(a) == 0 {
|
|
return nil
|
|
}
|
|
switch a[0] {
|
|
case AtypIPv4:
|
|
var ip [net.IPv4len]byte
|
|
copy(ip[0:], a[1:1+net.IPv4len])
|
|
return &net.UDPAddr{IP: net.IP(ip[:]), Port: int(binary.BigEndian.Uint16(a[1+net.IPv4len : 1+net.IPv4len+2]))}
|
|
case AtypIPv6:
|
|
var ip [net.IPv6len]byte
|
|
copy(ip[0:], a[1:1+net.IPv6len])
|
|
return &net.UDPAddr{IP: net.IP(ip[:]), Port: int(binary.BigEndian.Uint16(a[1+net.IPv6len : 1+net.IPv6len+2]))}
|
|
}
|
|
// Other Atyp
|
|
return nil
|
|
}
|
|
|
|
// SOCKS errors as defined in RFC 1928 section 6.
|
|
const (
|
|
ErrGeneralFailure = Error(1)
|
|
ErrConnectionNotAllowed = Error(2)
|
|
ErrNetworkUnreachable = Error(3)
|
|
ErrHostUnreachable = Error(4)
|
|
ErrConnectionRefused = Error(5)
|
|
ErrTTLExpired = Error(6)
|
|
ErrCommandNotSupported = Error(7)
|
|
ErrAddressNotSupported = Error(8)
|
|
)
|
|
|
|
// Auth errors used to return a specific "Auth failed" error
|
|
var ErrAuth = errors.New("auth failed")
|
|
|
|
type User struct {
|
|
Username string
|
|
Password string
|
|
}
|
|
|
|
// ServerHandshake fast-tracks SOCKS initialization to get target address to connect on server side.
|
|
func ServerHandshake(rw net.Conn, authenticator auth.Authenticator) (addr Addr, command Command, err error) {
|
|
// Read RFC 1928 for request and reply structure and sizes.
|
|
buf := make([]byte, MaxAddrLen)
|
|
// read VER, NMETHODS, METHODS
|
|
if _, err = io.ReadFull(rw, buf[:2]); err != nil {
|
|
return
|
|
}
|
|
nmethods := buf[1]
|
|
if _, err = io.ReadFull(rw, buf[:nmethods]); err != nil {
|
|
return
|
|
}
|
|
|
|
// write VER METHOD
|
|
if authenticator != nil {
|
|
if _, err = rw.Write([]byte{5, 2}); err != nil {
|
|
return
|
|
}
|
|
|
|
// Get header
|
|
header := make([]byte, 2)
|
|
if _, err = io.ReadFull(rw, header); err != nil {
|
|
return
|
|
}
|
|
|
|
authBuf := make([]byte, MaxAuthLen)
|
|
// Get username
|
|
userLen := int(header[1])
|
|
if userLen <= 0 {
|
|
rw.Write([]byte{1, 1})
|
|
err = ErrAuth
|
|
return
|
|
}
|
|
if _, err = io.ReadFull(rw, authBuf[:userLen]); err != nil {
|
|
return
|
|
}
|
|
user := string(authBuf[:userLen])
|
|
|
|
// Get password
|
|
if _, err = rw.Read(header[:1]); err != nil {
|
|
return
|
|
}
|
|
passLen := int(header[0])
|
|
if passLen <= 0 {
|
|
rw.Write([]byte{1, 1})
|
|
err = ErrAuth
|
|
return
|
|
}
|
|
if _, err = io.ReadFull(rw, authBuf[:passLen]); err != nil {
|
|
return
|
|
}
|
|
pass := string(authBuf[:passLen])
|
|
|
|
// Verify
|
|
if ok := authenticator.Verify(string(user), string(pass)); !ok {
|
|
rw.Write([]byte{1, 1})
|
|
err = ErrAuth
|
|
return
|
|
}
|
|
|
|
// Response auth state
|
|
if _, err = rw.Write([]byte{1, 0}); err != nil {
|
|
return
|
|
}
|
|
} else {
|
|
if _, err = rw.Write([]byte{5, 0}); err != nil {
|
|
return
|
|
}
|
|
}
|
|
|
|
// read VER CMD RSV ATYP DST.ADDR DST.PORT
|
|
if _, err = io.ReadFull(rw, buf[:3]); err != nil {
|
|
return
|
|
}
|
|
|
|
command = buf[1]
|
|
addr, err = ReadAddr(rw, buf)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
switch command {
|
|
case CmdConnect, CmdUDPAssociate:
|
|
// Acquire server listened address info
|
|
localAddr := ParseAddr(rw.LocalAddr().String())
|
|
if localAddr == nil {
|
|
err = ErrAddressNotSupported
|
|
} else {
|
|
// write VER REP RSV ATYP BND.ADDR BND.PORT
|
|
_, err = rw.Write(bytes.Join([][]byte{{5, 0, 0}, localAddr}, []byte{}))
|
|
}
|
|
case CmdBind:
|
|
fallthrough
|
|
default:
|
|
err = ErrCommandNotSupported
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// ClientHandshake fast-tracks SOCKS initialization to get target address to connect on client side.
|
|
func ClientHandshake(rw io.ReadWriter, addr Addr, command Command, user *User) (Addr, error) {
|
|
buf := make([]byte, MaxAddrLen)
|
|
var err error
|
|
|
|
// VER, NMETHODS, METHODS
|
|
if user != nil {
|
|
_, err = rw.Write([]byte{5, 1, 2})
|
|
} else {
|
|
_, err = rw.Write([]byte{5, 1, 0})
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// VER, METHOD
|
|
if _, err := io.ReadFull(rw, buf[:2]); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if buf[0] != 5 {
|
|
return nil, errors.New("SOCKS version error")
|
|
}
|
|
|
|
if buf[1] == 2 {
|
|
// password protocol version
|
|
authMsg := &bytes.Buffer{}
|
|
authMsg.WriteByte(1)
|
|
authMsg.WriteByte(uint8(len(user.Username)))
|
|
authMsg.WriteString(user.Username)
|
|
authMsg.WriteByte(uint8(len(user.Password)))
|
|
authMsg.WriteString(user.Password)
|
|
|
|
if _, err := rw.Write(authMsg.Bytes()); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if _, err := io.ReadFull(rw, buf[:2]); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if buf[1] != 0 {
|
|
return nil, errors.New("rejected username/password")
|
|
}
|
|
} else if buf[1] != 0 {
|
|
return nil, errors.New("SOCKS need auth")
|
|
}
|
|
|
|
// VER, CMD, RSV, ADDR
|
|
if _, err := rw.Write(bytes.Join([][]byte{{5, command, 0}, addr}, []byte{})); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// VER, REP, RSV
|
|
if _, err := io.ReadFull(rw, buf[:3]); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return ReadAddr(rw, buf)
|
|
}
|
|
|
|
func ReadAddr(r io.Reader, b []byte) (Addr, error) {
|
|
if len(b) < MaxAddrLen {
|
|
return nil, io.ErrShortBuffer
|
|
}
|
|
_, err := io.ReadFull(r, b[:1]) // read 1st byte for address type
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
switch b[0] {
|
|
case AtypDomainName:
|
|
_, err = io.ReadFull(r, b[1:2]) // read 2nd byte for domain length
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
domainLength := uint16(b[1])
|
|
_, err = io.ReadFull(r, b[2:2+domainLength+2])
|
|
return b[:1+1+domainLength+2], err
|
|
case AtypIPv4:
|
|
_, err = io.ReadFull(r, b[1:1+net.IPv4len+2])
|
|
return b[:1+net.IPv4len+2], err
|
|
case AtypIPv6:
|
|
_, err = io.ReadFull(r, b[1:1+net.IPv6len+2])
|
|
return b[:1+net.IPv6len+2], err
|
|
}
|
|
|
|
return nil, ErrAddressNotSupported
|
|
}
|
|
|
|
// SplitAddr slices a SOCKS address from beginning of b. Returns nil if failed.
|
|
func SplitAddr(b []byte) Addr {
|
|
addrLen := 1
|
|
if len(b) < addrLen {
|
|
return nil
|
|
}
|
|
|
|
switch b[0] {
|
|
case AtypDomainName:
|
|
if len(b) < 2 {
|
|
return nil
|
|
}
|
|
addrLen = 1 + 1 + int(b[1]) + 2
|
|
case AtypIPv4:
|
|
addrLen = 1 + net.IPv4len + 2
|
|
case AtypIPv6:
|
|
addrLen = 1 + net.IPv6len + 2
|
|
default:
|
|
return nil
|
|
|
|
}
|
|
|
|
if len(b) < addrLen {
|
|
return nil
|
|
}
|
|
|
|
return b[:addrLen]
|
|
}
|
|
|
|
// ParseAddr parses the address in string s. Returns nil if failed.
|
|
func ParseAddr(s string) Addr {
|
|
var addr Addr
|
|
host, port, err := net.SplitHostPort(s)
|
|
if err != nil {
|
|
return nil
|
|
}
|
|
if ip := net.ParseIP(host); ip != nil {
|
|
if ip4 := ip.To4(); ip4 != nil {
|
|
addr = make([]byte, 1+net.IPv4len+2)
|
|
addr[0] = AtypIPv4
|
|
copy(addr[1:], ip4)
|
|
} else {
|
|
addr = make([]byte, 1+net.IPv6len+2)
|
|
addr[0] = AtypIPv6
|
|
copy(addr[1:], ip)
|
|
}
|
|
} else {
|
|
if len(host) > 255 {
|
|
return nil
|
|
}
|
|
addr = make([]byte, 1+1+len(host)+2)
|
|
addr[0] = AtypDomainName
|
|
addr[1] = byte(len(host))
|
|
copy(addr[2:], host)
|
|
}
|
|
|
|
portnum, err := strconv.ParseUint(port, 10, 16)
|
|
if err != nil {
|
|
return nil
|
|
}
|
|
|
|
addr[len(addr)-2], addr[len(addr)-1] = byte(portnum>>8), byte(portnum)
|
|
|
|
return addr
|
|
}
|
|
|
|
// ParseAddrToSocksAddr parse a socks addr from net.addr
|
|
// This is a fast path of ParseAddr(addr.String())
|
|
func ParseAddrToSocksAddr(addr net.Addr) Addr {
|
|
var hostip net.IP
|
|
var port int
|
|
if udpaddr, ok := addr.(*net.UDPAddr); ok {
|
|
hostip = udpaddr.IP
|
|
port = udpaddr.Port
|
|
} else if tcpaddr, ok := addr.(*net.TCPAddr); ok {
|
|
hostip = tcpaddr.IP
|
|
port = tcpaddr.Port
|
|
}
|
|
|
|
// fallback parse
|
|
if hostip == nil {
|
|
return ParseAddr(addr.String())
|
|
}
|
|
|
|
var parsed Addr
|
|
if ip4 := hostip.To4(); ip4.DefaultMask() != nil {
|
|
parsed = make([]byte, 1+net.IPv4len+2)
|
|
parsed[0] = AtypIPv4
|
|
copy(parsed[1:], ip4)
|
|
binary.BigEndian.PutUint16(parsed[1+net.IPv4len:], uint16(port))
|
|
|
|
} else {
|
|
parsed = make([]byte, 1+net.IPv6len+2)
|
|
parsed[0] = AtypIPv6
|
|
copy(parsed[1:], hostip)
|
|
binary.BigEndian.PutUint16(parsed[1+net.IPv6len:], uint16(port))
|
|
}
|
|
return parsed
|
|
}
|
|
|
|
// DecodeUDPPacket split `packet` to addr payload, and this function is mutable with `packet`
|
|
func DecodeUDPPacket(packet []byte) (addr Addr, payload []byte, err error) {
|
|
if len(packet) < 5 {
|
|
err = errors.New("insufficient length of packet")
|
|
return
|
|
}
|
|
|
|
// packet[0] and packet[1] are reserved
|
|
if !bytes.Equal(packet[:2], []byte{0, 0}) {
|
|
err = errors.New("reserved fields should be zero")
|
|
return
|
|
}
|
|
|
|
if packet[2] != 0 /* fragments */ {
|
|
err = errors.New("discarding fragmented payload")
|
|
return
|
|
}
|
|
|
|
addr = SplitAddr(packet[3:])
|
|
if addr == nil {
|
|
err = errors.New("failed to read UDP header")
|
|
}
|
|
|
|
payload = packet[3+len(addr):]
|
|
return
|
|
}
|
|
|
|
func EncodeUDPPacket(addr Addr, payload []byte) (packet []byte, err error) {
|
|
if addr == nil {
|
|
err = errors.New("address is invalid")
|
|
return
|
|
}
|
|
packet = bytes.Join([][]byte{{0, 0, 0}, addr, payload}, []byte{})
|
|
return
|
|
}
|