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local.go
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local.go
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package easyss
import (
"fmt"
"io"
"net"
"strconv"
"github.com/nange/easyss/v2/cipherstream"
"github.com/nange/easyss/v2/log"
"github.com/nange/easyss/v2/util"
"github.com/txthinking/socks5"
)
func (ss *Easyss) LocalSocks5() {
var addr string
if ss.BindAll() {
addr = "[::]:" + strconv.Itoa(ss.LocalPort())
} else {
addr = "127.0.0.1:" + strconv.Itoa(ss.LocalPort())
}
log.Info("[SOCKS5] starting local socks5 server at", "addr", addr)
server, err := socks5.NewClassicServer(addr, "127.0.0.1", ss.AuthUsername(), ss.AuthPassword(), 0, 0)
if err != nil {
log.Error("[SOCKS5] new socks5 server", "err", err)
return
}
ss.SetSocksServer(server)
if err := server.ListenAndServe(ss); err != nil {
log.Warn("[SOCKS5] local socks5 server", "err", err)
}
}
func (ss *Easyss) TCPHandle(s *socks5.Server, conn *net.TCPConn, r *socks5.Request) error {
targetAddr := r.Address()
log.Debug("[SOCKS5]", "target", targetAddr, "is_udp", r.Cmd == socks5.CmdUDP)
if r.Cmd == socks5.CmdConnect {
a, addr, port, err := socks5.ParseAddress(conn.LocalAddr().String())
if err != nil {
log.Error("[SOCKS5] socks5 ParseAddress", "err", err)
return err
}
p := socks5.NewReply(socks5.RepSuccess, a, addr, port)
if _, err := p.WriteTo(conn); err != nil {
return err
}
return ss.localRelay(conn, targetAddr)
}
if r.Cmd == socks5.CmdUDP {
uaddr, _ := net.ResolveUDPAddr("udp", conn.LocalAddr().String())
caddr, err := r.UDP(conn, uaddr)
if err != nil {
return err
}
// if client udp addr isn't private ip, we do not set associated udp
// this case may be fired by non-standard socks5 implements
if caddr.(*net.UDPAddr).IP.IsLoopback() || caddr.(*net.UDPAddr).IP.IsPrivate() ||
caddr.(*net.UDPAddr).IP.IsUnspecified() {
ch := make(chan struct{}, 2)
portStr := strconv.FormatInt(int64(caddr.(*net.UDPAddr).Port), 10)
s.AssociatedUDP.Set(portStr, ch, -1)
defer func() {
log.Debug("[SOCKS5] exit associate tcp connection, closing chan")
ch <- struct{}{}
s.AssociatedUDP.Delete(portStr)
}()
}
_, _ = io.Copy(io.Discard, conn)
log.Debug("[SOCKS5] a tcp connection that udp associated closed",
"udp_addr", caddr.String(), "target_addr", targetAddr)
return nil
}
return socks5.ErrUnsupportCmd
}
func (ss *Easyss) localRelay(localConn net.Conn, addr string) (err error) {
host, _, _ := net.SplitHostPort(addr)
rule := ss.MatchHostRule(host)
if rule == HostRuleBlock {
log.Info("[TCP_BLOCK] blocked", "host", host)
return err
}
if rule == HostRuleDirect {
return ss.directRelay(localConn, addr)
}
log.Info("[TCP_PROXY]", "target", addr)
if !ss.disableValidateAddr {
if err := ss.validateAddr(addr); err != nil {
log.Error("[TCP_PROXY] validate socks5 request", "err", err)
return err
}
}
csStream, err := ss.handShakeWithRemote(addr, cipherstream.FlagTCP)
if err != nil {
log.Warn("[TCP_PROXY] handshake with remote server", "err", err)
if csStream != nil {
if cs, ok := csStream.(*cipherstream.CipherStream); ok {
cs.MarkConnUnusable()
}
csStream.Close()
}
return
}
defer csStream.Close()
tryReuse := true
if !ss.IsNativeOutboundProto() {
tryReuse = false
}
n1, n2, err := relay(csStream, localConn, ss.Timeout(), tryReuse)
log.Debug("[TCP_PROXY] send bytes to, receive bytes", "send", n1, "to", addr, "receive", n2, "err", err)
ss.stat.BytesSend.Add(n1)
ss.stat.BytesReceive.Add(n2)
return
}
func (ss *Easyss) validateAddr(addr string) error {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return fmt.Errorf("invalid target address:%v, err:%v", addr, err)
}
serverPort := strconv.FormatInt(int64(ss.ServerPort()), 10)
if !util.IsIP(host) {
if host == ss.Server() && port == serverPort {
return fmt.Errorf("target %s:%s equals to server host,port, which may caused infinite-loop", host, port)
}
return nil
}
if util.IsLANIP(host) {
return fmt.Errorf("target host:%v is LAN ip, which is invalid", host)
}
if ss.ShouldIPV6Disable() && util.IsIPV6(host) {
return fmt.Errorf("target %s is ipv6, but ipv6 network is disabled", host)
}
if (host == ss.ServerIP() || host == ss.ServerIPV6()) && port == serverPort {
return fmt.Errorf("target %s:%s equals server host,port, which may caused infinite-loop", host, port)
}
return nil
}
func (ss *Easyss) handShakeWithRemote(addr string, flag uint8) (net.Conn, error) {
stream, err := ss.AvailableConn()
if err != nil {
log.Error("[TCP_PROXY] get stream from pool failed", "err", err)
return nil, err
}
csStream, err := func() (*cipherstream.CipherStream, error) {
cs, err := cipherstream.New(stream, ss.Password(), cipherstream.MethodAes256GCM, cipherstream.FrameTypeData, flag)
csStream := cs.(*cipherstream.CipherStream)
if err != nil {
log.Error("[TCP_PROXY] new cipherstream", "err", err)
return csStream, err
}
cipherMethod := EncodeCipherMethod(ss.Method())
frame := cipherstream.NewFrame(cipherstream.FrameTypeData, append([]byte(addr), cipherMethod), flag, csStream.AEADCipher)
if err := csStream.WriteFrame(frame); err != nil {
return csStream, err
}
return csStream, nil
}()
if err != nil {
return csStream, err
}
csStream.Release()
return cipherstream.New(stream, ss.Password(), ss.Method(), cipherstream.FrameTypeData, flag)
}
func EncodeCipherMethod(m string) byte {
switch m {
case "aes-256-gcm":
return 1
case "chacha20-poly1305":
return 2
default:
return 0
}
}