forked from ginuerzh/gost
/
ss.go
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/
ss.go
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package gost
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"github.com/ginuerzh/gosocks5"
"github.com/golang/glog"
ss "github.com/ARwMq9b6/libgost/vendors/github.com/shadowsocks/shadowsocks-go/shadowsocks"
"io"
"net"
"strconv"
"time"
)
const (
idType = 0 // address type index
idIP0 = 1 // ip addres start index
idDmLen = 1 // domain address length index
idDm0 = 2 // domain address start index
typeIPv4 = 1 // type is ipv4 address
typeDm = 3 // type is domain address
typeIPv6 = 4 // type is ipv6 address
lenIPv4 = net.IPv4len + 2 // ipv4 + 2port
lenIPv6 = net.IPv6len + 2 // ipv6 + 2port
lenDmBase = 2 // 1addrLen + 2port, plus addrLen
lenHmacSha1 = 10
)
type ShadowServer struct {
conn *ss.Conn
Base *ProxyServer
OTA bool // one time auth
}
func NewShadowServer(conn *ss.Conn, base *ProxyServer) *ShadowServer {
return &ShadowServer{conn: conn, Base: base}
}
func (s *ShadowServer) Serve() {
glog.V(LINFO).Infof("[ss] %s - %s", s.conn.RemoteAddr(), s.conn.LocalAddr())
addr, ota, err := s.getRequest()
if err != nil {
glog.V(LWARNING).Infof("[ss] %s - %s : %s", s.conn.RemoteAddr(), s.conn.LocalAddr(), err)
return
}
glog.V(LINFO).Infof("[ss] %s -> %s, ota: %v", s.conn.RemoteAddr(), addr, ota)
cc, err := s.Base.Chain.Dial(addr)
if err != nil {
glog.V(LWARNING).Infof("[ss] %s -> %s : %s", s.conn.RemoteAddr(), addr, err)
return
}
defer cc.Close()
glog.V(LINFO).Infof("[ss] %s <-> %s", s.conn.RemoteAddr(), addr)
if ota {
s.transportOTA(s.conn, cc)
} else {
s.Base.transport(&shadowConn{conn: s.conn}, cc)
}
glog.V(LINFO).Infof("[ss] %s >-< %s", s.conn.RemoteAddr(), addr)
}
// This function is copied from shadowsocks library with some modification.
func (s *ShadowServer) getRequest() (host string, ota bool, err error) {
// buf size should at least have the same size with the largest possible
// request size (when addrType is 3, domain name has at most 256 bytes)
// 1(addrType) + 1(lenByte) + 256(max length address) + 2(port)
buf := make([]byte, SmallBufferSize)
// read till we get possible domain length field
s.conn.SetReadDeadline(time.Now().Add(ReadTimeout))
if _, err = io.ReadFull(s.conn, buf[:idType+1]); err != nil {
return
}
var reqStart, reqEnd int
addrType := buf[idType]
switch addrType & ss.AddrMask {
case typeIPv4:
reqStart, reqEnd = idIP0, idIP0+lenIPv4
case typeIPv6:
reqStart, reqEnd = idIP0, idIP0+lenIPv6
case typeDm:
if _, err = io.ReadFull(s.conn, buf[idType+1:idDmLen+1]); err != nil {
return
}
reqStart, reqEnd = idDm0, int(idDm0+buf[idDmLen]+lenDmBase)
default:
err = fmt.Errorf("addr type %d not supported", addrType&ss.AddrMask)
return
}
if _, err = io.ReadFull(s.conn, buf[reqStart:reqEnd]); err != nil {
return
}
// Return string for typeIP is not most efficient, but browsers (Chrome,
// Safari, Firefox) all seems using typeDm exclusively. So this is not a
// big problem.
switch addrType & ss.AddrMask {
case typeIPv4:
host = net.IP(buf[idIP0 : idIP0+net.IPv4len]).String()
case typeIPv6:
host = net.IP(buf[idIP0 : idIP0+net.IPv6len]).String()
case typeDm:
host = string(buf[idDm0 : idDm0+buf[idDmLen]])
}
// parse port
port := binary.BigEndian.Uint16(buf[reqEnd-2 : reqEnd])
host = net.JoinHostPort(host, strconv.Itoa(int(port)))
// if specified one time auth enabled, we should verify this
if s.OTA || addrType&ss.OneTimeAuthMask > 0 {
ota = true
if _, err = io.ReadFull(s.conn, buf[reqEnd:reqEnd+lenHmacSha1]); err != nil {
return
}
iv := s.conn.GetIv()
key := s.conn.GetKey()
actualHmacSha1Buf := ss.HmacSha1(append(iv, key...), buf[:reqEnd])
if !bytes.Equal(buf[reqEnd:reqEnd+lenHmacSha1], actualHmacSha1Buf) {
err = fmt.Errorf("verify one time auth failed, iv=%v key=%v data=%v", iv, key, buf[:reqEnd])
return
}
}
return
}
const (
dataLenLen = 2
hmacSha1Len = 10
idxData0 = dataLenLen + hmacSha1Len
)
// copyOta copies data from src to dst with ota verification.
//
// This function is copied from shadowsocks library with some modification.
func (s *ShadowServer) copyOta(dst net.Conn, src *ss.Conn) (int64, error) {
// sometimes it have to fill large block
buf := make([]byte, LargeBufferSize)
for {
src.SetReadDeadline(time.Now().Add(ReadTimeout))
if n, err := io.ReadFull(src, buf[:dataLenLen+hmacSha1Len]); err != nil {
return int64(n), err
}
src.SetReadDeadline(time.Time{})
dataLen := binary.BigEndian.Uint16(buf[:dataLenLen])
expectedHmacSha1 := buf[dataLenLen:idxData0]
var dataBuf []byte
if len(buf) < int(idxData0+dataLen) {
dataBuf = make([]byte, dataLen)
} else {
dataBuf = buf[idxData0 : idxData0+dataLen]
}
if n, err := io.ReadFull(src, dataBuf); err != nil {
return int64(n), err
}
chunkIdBytes := make([]byte, 4)
chunkId := src.GetAndIncrChunkId()
binary.BigEndian.PutUint32(chunkIdBytes, chunkId)
actualHmacSha1 := ss.HmacSha1(append(src.GetIv(), chunkIdBytes...), dataBuf)
if !bytes.Equal(expectedHmacSha1, actualHmacSha1) {
return 0, errors.New("ota error: mismatch")
}
if n, err := dst.Write(dataBuf); err != nil {
return int64(n), err
}
}
}
func (s *ShadowServer) transportOTA(sc *ss.Conn, cc net.Conn) (err error) {
errc := make(chan error, 2)
go func() {
_, err := io.Copy(&shadowConn{conn: sc}, cc)
errc <- err
}()
go func() {
_, err := s.copyOta(cc, sc)
errc <- err
}()
select {
case err = <-errc:
//glog.V(LWARNING).Infoln("transport exit", err)
}
return
}
// Due to in/out byte length is inconsistent of the shadowsocks.Conn.Write,
// we wrap around it to make io.Copy happy
type shadowConn struct {
conn *ss.Conn
}
func (c *shadowConn) Read(b []byte) (n int, err error) {
return c.conn.Read(b)
}
func (c *shadowConn) Write(b []byte) (n int, err error) {
n = len(b) // force byte length consistent
_, err = c.conn.Write(b)
return
}
func (c *shadowConn) Close() error {
return c.conn.Close()
}
func (c *shadowConn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *shadowConn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *shadowConn) SetDeadline(t time.Time) error {
return c.conn.SetDeadline(t)
}
func (c *shadowConn) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
func (c *shadowConn) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}
type ShadowUdpServer struct {
Base *ProxyServer
TTL int
}
func NewShadowUdpServer(base *ProxyServer, ttl int) *ShadowUdpServer {
return &ShadowUdpServer{Base: base, TTL: ttl}
}
func (s *ShadowUdpServer) ListenAndServe() error {
laddr, err := net.ResolveUDPAddr("udp", s.Base.Node.Addr)
if err != nil {
return err
}
lconn, err := net.ListenUDP("udp", laddr)
if err != nil {
return err
}
defer lconn.Close()
conn := ss.NewSecurePacketConn(lconn, s.Base.cipher.Copy(), true) // force OTA on
rChan, wChan := make(chan *packet, 128), make(chan *packet, 128)
// start send queue
go func(ch chan<- *packet) {
for {
b := make([]byte, MediumBufferSize)
n, addr, err := conn.ReadFrom(b[3:]) // add rsv and frag fields to make it the standard SOCKS5 UDP datagram
if err != nil {
glog.V(LWARNING).Infof("[ssu] %s -> %s : %s", addr, laddr, err)
continue
}
b[3] &= ss.AddrMask // remove OTA flag
dgram, err := gosocks5.ReadUDPDatagram(bytes.NewReader(b[:n+3]))
if err != nil {
glog.V(LWARNING).Infof("[ssu] %s -> %s : %s", addr, laddr, err)
continue
}
select {
case ch <- &packet{srcAddr: addr.String(), dstAddr: dgram.Header.Addr.String(), data: dgram.Data}:
case <-time.After(time.Second * 3):
glog.V(LWARNING).Infof("[ssu] %s -> %s : %s", addr, dgram.Header.Addr.String(), "send queue is full, discard")
}
}
}(wChan)
// start recv queue
go func(ch <-chan *packet) {
for pkt := range ch {
srcAddr, err := net.ResolveUDPAddr("udp", pkt.srcAddr)
if err != nil {
glog.V(LWARNING).Infof("[ssu] %s <- %s : %s", pkt.dstAddr, pkt.srcAddr, err)
continue
}
dstAddr, err := net.ResolveUDPAddr("udp", pkt.dstAddr)
if err != nil {
glog.V(LWARNING).Infof("[ssu] %s <- %s : %s", pkt.dstAddr, pkt.srcAddr, err)
continue
}
dgram := gosocks5.NewUDPDatagram(gosocks5.NewUDPHeader(0, 0, ToSocksAddr(srcAddr)), pkt.data)
b := bytes.Buffer{}
dgram.Write(&b)
if b.Len() < 10 {
glog.V(LWARNING).Infof("[ssu] %s <- %s : invalid udp datagram", pkt.dstAddr, pkt.srcAddr)
continue
}
if _, err := conn.WriteTo(b.Bytes()[3:], dstAddr); err != nil { // remove rsv and frag fields to make it standard shadowsocks UDP datagram
glog.V(LWARNING).Infof("[ssu] %s <- %s : %s", pkt.dstAddr, pkt.srcAddr, err)
return
}
}
}(rChan)
// mapping client to node
m := make(map[string]*cnode)
// start dispatcher
for pkt := range wChan {
// clear obsolete nodes
for k, node := range m {
if node != nil && node.err != nil {
close(node.wChan)
delete(m, k)
glog.V(LINFO).Infof("[ssu] clear node %s", k)
}
}
node, ok := m[pkt.srcAddr]
if !ok {
node = &cnode{
chain: s.Base.Chain,
srcAddr: pkt.srcAddr,
dstAddr: pkt.dstAddr,
rChan: rChan,
wChan: make(chan *packet, 32),
ttl: time.Duration(s.TTL) * time.Second,
}
m[pkt.srcAddr] = node
go node.run()
glog.V(LINFO).Infof("[ssu] %s -> %s : new client (%d)", pkt.srcAddr, pkt.dstAddr, len(m))
}
select {
case node.wChan <- pkt:
case <-time.After(time.Second * 3):
glog.V(LWARNING).Infof("[ssu] %s -> %s : %s", pkt.srcAddr, pkt.dstAddr, "node send queue is full, discard")
}
}
return nil
}