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server.go
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server.go
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package vmess
import (
"context"
"crypto/aes"
"crypto/cipher"
"crypto/hmac"
"crypto/md5"
"encoding/binary"
"errors"
"fmt"
"github.com/faireal/trojan-go/api/service"
"github.com/faireal/trojan-go/common"
"github.com/faireal/trojan-go/config"
"github.com/faireal/trojan-go/log"
"github.com/faireal/trojan-go/redirector"
"github.com/faireal/trojan-go/statistic"
"github.com/faireal/trojan-go/statistic/memory"
"github.com/faireal/trojan-go/statistic/mysql"
"github.com/faireal/trojan-go/tunnel"
"golang.org/x/crypto/chacha20poly1305"
"hash/fnv"
"io"
"net"
"sync"
"sync/atomic"
"time"
)
const (
updateInterval = 30 * time.Second
cacheDurationSec = 60
sessionTimeOut = 3 * time.Minute
)
// InboundConn is a vmess inbound connection
type InboundConn struct {
// WARNING: do not change the order of these fields.
// 64-bit fields that use `sync/atomic` package functions
// must be 64-bit aligned on 32-bit systems.
// Reference: https://github.com/golang/go/issues/599
// Solution: https://github.com/golang/go/issues/11891#issuecomment-433623786
sent uint64
recv uint64
net.Conn
auth statistic.Authenticator
user statistic.User
hash string
metadata *tunnel.Metadata
ip string
// header
dataReader io.Reader
dataWriter io.Writer
opt byte
security byte
reqBodyIV [16]byte
reqBodyKey [16]byte
reqRespV byte
respBodyIV [16]byte
respBodyKey [16]byte
}
type UserAtTime struct {
user statistic.User
timeInc int64
tainted bool // 是否被重放攻击污染
}
type SessionId struct {
user [16]byte
key [16]byte
nonce [16]byte
}
func (c *InboundConn) Metadata() *tunnel.Metadata {
return c.metadata
}
func (c *InboundConn) Write(p []byte) (int, error) {
if c.dataWriter == nil {
// 编码响应头
// 应答头部数据使用 AES-128-CFB 加密,IV 为 MD5(数据加密 IV),Key 为 MD5(数据加密 Key)
buf := GetWriteBuffer()
defer PutWriteBuffer(buf)
buf.WriteByte(c.reqRespV) // 响应认证 V
buf.WriteByte(c.opt) // 选项 Opt
buf.Write([]byte{0, 0}) // 指令 Cmd 和 长度 M, 不支持动态端口指令
c.respBodyKey = md5.Sum(c.reqBodyKey[:])
c.respBodyIV = md5.Sum(c.reqBodyIV[:])
block, err := aes.NewCipher(c.respBodyKey[:])
if err != nil {
return 0, err
}
stream := cipher.NewCFBEncrypter(block, c.respBodyIV[:])
stream.XORKeyStream(buf.Bytes(), buf.Bytes())
_, err = c.Conn.Write(buf.Bytes())
if err != nil {
return 0, err
}
// 编码内容
c.dataWriter = c.Conn
if c.opt&OptChunkStream == OptChunkStream {
switch c.security {
case SecurityNone:
c.dataWriter = ChunkedWriter(c.Conn)
case SecurityAES128GCM:
block, _ := aes.NewCipher(c.respBodyKey[:])
aead, _ := cipher.NewGCM(block)
c.dataWriter = AEADWriter(c.Conn, aead, c.respBodyIV[:])
case SecurityChacha20Poly1305:
key := GetBuffer(32)
t := md5.Sum(c.respBodyKey[:])
copy(key, t[:])
t = md5.Sum(key[:16])
copy(key[16:], t[:])
aead, _ := chacha20poly1305.New(key)
c.dataWriter = AEADWriter(c.Conn, aead, c.respBodyIV[:])
PutBuffer(key)
}
}
}
n, err := c.dataWriter.Write(p)
atomic.AddUint64(&c.sent, uint64(n))
c.user.AddTraffic(n, 0)
return n, err
}
func (c *InboundConn) Read(p []byte) (n int, err error) {
if c.dataReader == nil {
// 解码数据部分
c.dataReader = c.Conn
if c.opt&OptChunkStream == OptChunkStream {
switch c.security {
case SecurityNone:
c.dataReader = ChunkedReader(c.Conn)
case SecurityAES128GCM:
block, _ := aes.NewCipher(c.reqBodyKey[:])
aead, _ := cipher.NewGCM(block)
c.dataReader = AEADReader(c.Conn, aead, c.reqBodyIV[:])
case SecurityChacha20Poly1305:
key := GetBuffer(32)
t := md5.Sum(c.reqBodyKey[:])
copy(key, t[:])
t = md5.Sum(key[:16])
copy(key[16:], t[:])
aead, _ := chacha20poly1305.New(key)
c.dataReader = AEADReader(c.Conn, aead, c.reqBodyIV[:])
PutBuffer(key)
}
}
}
n, err = c.dataReader.Read(p)
atomic.AddUint64(&c.recv, uint64(n))
c.user.AddTraffic(0, n)
return n, err
}
func (c *InboundConn) Close() error {
log.Info("user", c.hash, "from", c.Conn.RemoteAddr(), "tunneling to", c.metadata.Address, "closed",
"sent:", common.HumanFriendlyTraffic(atomic.LoadUint64(&c.sent)), "recv:", common.HumanFriendlyTraffic(atomic.LoadUint64(&c.recv)))
c.user.DelIP(c.ip)
return c.Conn.Close()
}
type Server struct {
auth statistic.Authenticator
redir *redirector.Redirector
redirAddr *tunnel.Address
underlay tunnel.Server
connChan chan tunnel.Conn
ctx context.Context
cancel context.CancelFunc
// userHashes用于校验VMess请求的认证信息部分
// sessionHistory保存一段时间内的请求用来检测重放攻击
baseTime int64
userHashes map[[16]byte]*UserAtTime
sessionHistory map[SessionId]time.Time
// 定时刷新userHashes和sessionHistory
mux4Hashes, mux4Sessions sync.RWMutex
ticker *time.Ticker
quit chan struct{}
}
func (s *Server) acceptLoop() {
for {
conn, err := s.underlay.AcceptConn(&Tunnel{})
if err != nil { // Closing
log.Error(common.NewError("vmess failed to accept conn").Base(err))
select {
case <-s.ctx.Done():
return
default:
}
continue
}
go func(conn tunnel.Conn) {
rewindConn := common.NewRewindConn(conn)
rewindConn.SetBufferSize(4086)
defer rewindConn.StopBuffering()
inboundConn := &InboundConn{
Conn: rewindConn,
}
if err := s.handshake(inboundConn); err != nil {
rewindConn.Rewind()
rewindConn.StopBuffering()
log.Warn(common.NewError("connection with invalid vmess header from " + rewindConn.RemoteAddr().String()).Base(err))
s.redir.Redirect(&redirector.Redirection{
RedirectTo: s.redirAddr,
InboundConn: rewindConn,
})
return
}
rewindConn.StopBuffering()
s.connChan <- inboundConn
log.Debug("normal vmess connection")
}(conn)
}
}
func (s *Server) AcceptConn(t tunnel.Tunnel) (tunnel.Conn, error) {
select {
case c := <-s.connChan:
return c, nil
case <-s.ctx.Done():
return nil, common.NewError("vmess client closed")
}
}
func (s *Server) AcceptPacket(t tunnel.Tunnel) (tunnel.PacketConn, error) {
//TODO implement me
panic("implement me")
}
func (s *Server) Close() error {
close(s.quit)
return s.underlay.Close()
}
func (s *Server) handshake(c *InboundConn) error {
// Set handshake timeout 4 seconds
//if err := c.SetReadDeadline(time.Now().Add(time.Second * 20)); err != nil {
// return err
//}
//defer c.SetReadDeadline(time.Time{})
var auth [16]byte
_, err := io.ReadFull(c.Conn, auth[:])
if err != nil {
return err
}
var timestamp int64
s.mux4Hashes.RLock()
uat, found := s.userHashes[auth]
if !found || uat.tainted {
s.mux4Hashes.RUnlock()
return errors.New("invalid user or tainted")
}
c.user = uat.user
timestamp = uat.timeInc + s.baseTime
s.mux4Hashes.RUnlock()
//
// 解开指令部分,该部分使用了AES-128-CFB加密
//
fullReq := GetWriteBuffer()
defer PutWriteBuffer(fullReq)
// 创建一个AES 加密器
cmdkey := c.user.CmdKey()
block, err := aes.NewCipher(cmdkey[:])
if err != nil {
return err
}
stream := cipher.NewCFBDecrypter(block, TimestampHash(timestamp))
// 41{1 + 16 + 16 + 1 + 1 + 1 + 1 + 1 + 2 + 1} + 1 + MAX{255} + MAX{15} + 4 = 362
req := GetBuffer(41)
defer PutBuffer(req)
_, err = io.ReadFull(c.Conn, req)
if err != nil {
return err
}
stream.XORKeyStream(req, req)
fullReq.Write(req)
copy(c.reqBodyIV[:], req[1:17]) // 16 bytes, 数据加密 IV
copy(c.reqBodyKey[:], req[17:33]) // 16 bytes, 数据加密 Key
var sid SessionId
uuid := c.user.UUID()
copy(sid.user[:], uuid[:])
sid.key = c.reqBodyKey
sid.nonce = c.reqBodyIV
s.mux4Sessions.Lock()
now := time.Now().UTC()
if expire, found := s.sessionHistory[sid]; found && expire.After(now) {
s.mux4Sessions.Unlock()
return errors.New("duplicated session id")
}
s.sessionHistory[sid] = now.Add(sessionTimeOut)
s.mux4Sessions.Unlock()
c.reqRespV = req[33] // 1 byte, 直接用于响应的认证
c.opt = req[34] // 1 byte
padingLen := int(req[35] >> 4) // 4 bits, 余量 P
c.security = req[35] & 0x0F // 4 bits, 加密方式 Sec
cmd := req[37] // 1 byte, 指令 Cmd
if cmd != CmdTCP {
return fmt.Errorf("unsuppoted command %v", cmd)
}
// 解析地址, 从41位开始读
addr := &tunnel.Address{}
addr.Port = int(binary.BigEndian.Uint16(req[38:40]))
l := 0
switch req[40] {
case AtypIP4:
l = net.IPv4len
addr.IP = make(net.IP, net.IPv4len)
addr.AddressType = tunnel.IPv4
case AtypDomain:
// 解码域名的长度
reqLength := GetBuffer(1)
defer PutBuffer(reqLength)
_, err = io.ReadFull(c.Conn, reqLength)
if err != nil {
return err
}
stream.XORKeyStream(reqLength, reqLength)
fullReq.Write(reqLength)
l = int(reqLength[0])
addr.AddressType = tunnel.DomainName
case AtypIP6:
l = net.IPv6len
addr.IP = make(net.IP, net.IPv6len)
addr.AddressType = tunnel.IPv6
default:
return fmt.Errorf("unknown address type %v", req[40])
}
// 解码剩余部分
reqRemaining := GetBuffer(l + padingLen + 4)
defer PutBuffer(reqRemaining)
_, err = io.ReadFull(c.Conn, reqRemaining)
if err != nil {
return err
}
stream.XORKeyStream(reqRemaining, reqRemaining)
fullReq.Write(reqRemaining)
if addr.IP != nil {
copy(addr.IP, reqRemaining[:l])
} else {
addr.DomainName = string(reqRemaining[:l])
}
full := fullReq.Bytes()
// log.Printf("Request Recv %v", full)
// 跳过余量读取四个字节的校验F
fnv1a := fnv.New32a()
_, err = fnv1a.Write(full[:len(full)-4])
if err != nil {
return err
}
actualHash := fnv1a.Sum32()
expectedHash := binary.BigEndian.Uint32(reqRemaining[len(reqRemaining)-4:])
if actualHash != expectedHash {
return errors.New("invalid req")
}
c.metadata = &tunnel.Metadata{Command: tunnel.Command(cmd), Address: addr}
// ip 限制
ip, _, err := net.SplitHostPort(c.Conn.RemoteAddr().String())
if err != nil {
return common.NewError("failed to parse host:" + c.Conn.RemoteAddr().String()).Base(err)
}
c.ip = ip
ok := c.user.AddIP(ip)
if !ok {
return common.NewError("ip limit reached")
}
return nil
}
func NewServer(ctx context.Context, underlay tunnel.Server) (*Server, error) {
cfg := config.FromContext(ctx, Name).(*Config)
ctx, cancel := context.WithCancel(ctx)
redirAddr := tunnel.NewAddressFromHostPort("tcp", cfg.RemoteHost, cfg.RemotePort)
// TODO replace this dirty code
var auth statistic.Authenticator
var err error
if cfg.MySQL.Enabled {
log.Info("mysql enabled")
auth, err = mysql.NewAuthenticator(ctx)
} else {
log.Info("auth by config file")
auth, err = memory.NewAuthenticator(ctx)
}
if err != nil {
cancel()
return nil, common.NewError("vmess failed to create authenticator")
}
s := &Server{
underlay: underlay,
auth: auth,
ctx: ctx,
redirAddr: redirAddr,
cancel: cancel,
connChan: make(chan tunnel.Conn, 32),
redir: redirector.NewRedirector(ctx),
}
if cfg.API.Enabled {
go service.RunServerAPI(ctx, auth)
}
err = s.auth.AddUser(cfg.UUID)
if err != nil {
return nil, err
}
s.baseTime = time.Now().UTC().Unix() - cacheDurationSec*2
s.userHashes = make(map[[16]byte]*UserAtTime, 1024)
s.sessionHistory = make(map[SessionId]time.Time, 128)
s.ticker = time.NewTicker(updateInterval)
s.quit = make(chan struct{})
go s.refreloop()
go s.acceptLoop()
return s, nil
}
func (s *Server) refreloop() {
s.refresh()
for {
select {
case <-s.ticker.C:
s.refresh()
case <-s.quit:
s.ticker.Stop()
return
}
}
}
func (s *Server) refresh() {
s.mux4Hashes.Lock()
now := time.Now().UTC()
nowSec := now.Unix()
genBeginSec := nowSec - cacheDurationSec
genEndSec := nowSec + cacheDurationSec
var hashValue [16]byte
users := s.auth.ListUsers()
for _, user := range users {
//uuid := user.UUID()
for _, uuid := range user.UUIDs() {
hasher := hmac.New(md5.New, uuid[:])
for ts := genBeginSec; ts <= genEndSec; ts++ {
var b [8]byte
binary.BigEndian.PutUint64(b[:], uint64(ts))
hasher.Write(b[:])
hasher.Sum(hashValue[:0])
hasher.Reset()
s.userHashes[hashValue] = &UserAtTime{
user: user,
timeInc: ts - s.baseTime,
tainted: false,
}
}
}
}
if genBeginSec > s.baseTime {
for k, v := range s.userHashes {
if v.timeInc+s.baseTime < genBeginSec {
delete(s.userHashes, k)
}
}
}
s.mux4Hashes.Unlock()
s.mux4Sessions.Lock()
for session, expire := range s.sessionHistory {
if expire.Before(now) {
delete(s.sessionHistory, session)
}
}
s.mux4Sessions.Unlock()
}
func (s *Server) AddUser(uuid string) error {
return nil
}
func (s *Server) DelUser(uuid string) error {
return nil
}