func (c *Client) ClientServe(conn net.Conn) {
var done bool
defer func() {
ex.Catch(recover(), nil)
if !done {
SafeClose(conn)
}
}()
reqNum := atomic.AddInt32(&c.reqCnt, 1)
pbConn := NewPushbackInputStream(conn)
proto, err := detectProtocol(pbConn)
if err != nil {
// chrome will make some advance connections and then aborted
// cause a EOF
if err != io.EOF && err != io.ErrUnexpectedEOF {
log.Warningln(err)
}
return
}
switch proto {
case PROT_SOCKS5:
s5 := socks5Handler{pbConn}
if s5.handshake() {
if literalTarget, ok := s5.readRequest(); ok {
c.mux.HandleRequest("SOCKS5", conn, literalTarget)
done = true
}
}
case PROT_HTTP:
proto, target, err := httpProxyHandshake(pbConn)
if err != nil {
log.Warningln(err)
break
}
switch proto {
case PROT_HTTP:
// plain http
c.mux.HandleRequest("HTTP", pbConn, target)
case PROT_HTTP_T:
// http tunnel
c.mux.HandleRequest("HTTP/T", conn, target)
case PROT_LOCAL:
// target is requestUri
c.localServlet(conn, target)
}
done = true
default:
log.Warningln("Unrecognized request from", conn.RemoteAddr())
time.Sleep(REST_INTERVAL)
}
// client setSeed at every 32 req
if reqNum&0x1f == 0x1f {
myRand.setSeed(0)
}
}
func (c *Client) getToken() ([]byte, error) {
c.lock.Lock()
var tlen = len(c.token) / TKSZ
if tlen <= TOKENS_FLOOR {
// TODO may request many times
c.asyncRequestTokens()
}
for len(c.token) < TKSZ {
// release lock for waiting of pendingTK()
c.lock.Unlock()
log.Warningln("Waiting for token. Maybe the requests are coming too fast.")
if !c.pendingTK.await(RETRY_INTERVAL * 2) {
// acquire() cancelled by clearAll()
return nil, ERR_REQ_TK_TIMEOUT
}
if atomic.LoadInt32(&c.state) < CLT_WORKING {
return nil, ERR_REQ_TK_ABORTED
}
// recover lock status
c.lock.Lock()
}
var token = c.token[:TKSZ]
c.token = c.token[TKSZ:]
// finally release
c.lock.Unlock()
return token, nil
}
func (c *Client) localServlet(conn net.Conn, reqUri string) {
initTplOnce.Do(lazyInitTemplate)
defer conn.Close()
switch reqUri {
case "/wpad.dat":
if c.connInfo.pacFile != NULL { // has pac setting
pacFile, info, err := openReadOnlyFile(c.connInfo.pacFile)
if err != nil {
log.Errorln("Read PAC file", err)
goto error404
}
defer pacFile.Close()
entity := respEntity{
contentType: "application/x-ns-proxy-autoconfig",
contentLength: int(info.Size()),
stream: pacFile,
}
writeHttpResponse(conn, 200, &entity)
return
}
case "/":
writeHttpResponse(conn, 200, c.renderPage("main"))
return
}
error404:
// other local request or pacFile not specified
log.Warningln("Unrecognized Request", reqUri)
// respond 404
writeHttpResponse(conn, 404, c.renderPage("404"))
}
// step3-4
func (s socks5Handler) readRequest() (string, bool) {
var (
buf = make([]byte, 262) // 4+(1+255)+2
host string
ofs int
ver, cmd, atyp byte
)
var msg = []byte{5, 0, 0, 1, 0, 0, 0, 0, 0, 0}
setRTimeout(s.conn)
_, err := s.conn.Read(buf)
if err != nil {
exception.Spawn(&err, "socks: read request")
goto errLogging
}
ver, cmd, atyp = buf[0], buf[1], buf[3]
if ver != S5_VER || cmd != 1 {
exception.Spawn(&err, "socks: invalid request")
goto errHandler
}
buf = buf[4:]
switch atyp {
case IPV4:
host = net.IP(buf[:net.IPv4len]).String()
ofs = net.IPv4len
case IPV6:
host = "[" + net.IP(buf[:net.IPv6len]).String() + "]"
ofs = net.IPv6len
case DOMAIN:
dlen := int(buf[0])
ofs = dlen + 1
host = string(buf[1:ofs])
// literal IPv6
if strings.Count(host, ":") >= 2 && !strings.HasPrefix(host, "[") {
host = "[" + host + "]"
}
default:
exception.Spawn(&err, "socks: invalid request")
goto errHandler
}
// accept
_, err = s.conn.Write(msg)
if err != nil {
exception.Spawn(&err, "socks: write response")
goto errLogging
}
host += ":" + strconv.Itoa(int(binary.BigEndian.Uint16(buf[ofs:])))
return host, true
errHandler:
msg[1] = 0x1 // general SOCKS server failure
setWTimeout(s.conn)
s.conn.Write(msg)
errLogging:
log.Warningln(err)
return NULL, false
}
func (n *d5cman) Connect(p *tunParams) (conn *Conn, err error) {
var rawConn net.Conn
defer func() {
n.dbcHello, n.sRand = nil, nil
if exception.Catch(recover(), &err) {
SafeClose(rawConn)
if t, y := err.(*exception.Exception); y {
// must terminate
switch t.Origin {
case ERR_TIME_ERROR:
line := string(bytes.Repeat([]byte{'+'}, 30))
log.Warningln(line)
log.Warningln("Maybe your clock is inaccurate, or your client credential is invalid.")
log.Warningln(line)
os.Exit(2)
case INCOMPATIBLE_VERSION:
log.Warningln(err)
os.Exit(3)
}
}
}
}()
rawConn, err = net.DialTimeout("tcp", n.sAddr, GENERAL_SO_TIMEOUT)
n.dhKey, _ = crypto.NewDHKey(DH_METHOD)
if err != nil {
return
}
conn = NewConn(rawConn, nullCipherKit)
if err = n.requestDHExchange(conn); err != nil {
return
}
var cf *CipherFactory
cf, err = n.finishDHExchange(conn)
if err != nil {
return
}
if err = n.validate(conn); err != nil {
return
}
if err = n.authThenFinishSetting(conn, p); err != nil {
return
}
p.cipherFactory = cf
conn.SetId(n.provider, false)
return
}
func (p *multiplexer) bestSend(data []byte, action_desc string) bool {
var buf = make([]byte, FRAME_HEADER_LEN+len(data))
pack(buf, FRAME_ACTION_TOKENS, 0, data)
for i := 1; i <= 3; i++ {
if atomic.LoadInt32(&p.status) < 0 /* MUX_CLOSED */ || p.pool == nil {
log.Warningln("Abandon sending data of", action_desc)
break
}
tun := p.pool.Select()
if tun != nil {
if frameWriteBuffer(tun, buf) == nil {
return true
}
} else {
time.Sleep(time.Millisecond * 200 * time.Duration(i))
}
}
log.Warningln("failed to send data of", action_desc)
return false
}
func (p *multiplexer) HandleRequest(prot string, client net.Conn, target string) {
if tun := p.pool.Select(); tun != nil {
sid := next_sid()
if log.V(log.LV_REQ) {
log.Infof("%s->[%s] from=%s sid=%d\n", prot, target, ipAddr(client.RemoteAddr()), sid)
}
key := sessionKey(tun, sid)
edge := p.router.register(key, target, tun, client, true) // write edge
p.relay(edge, tun, sid) // read edge
} else {
log.Warningln(ERR_TUN_NA)
time.Sleep(time.Second)
SafeClose(client)
}
}
// step1-2
func (s socks5Handler) handshake() bool {
var buf = make([]byte, 2)
var n, nmethods int
var ver byte
setRTimeout(s.conn)
_, err := io.ReadFull(s.conn, buf)
if err != nil {
exception.Spawn(&err, "socks: read header")
goto errLogging
}
ver, nmethods = buf[0], int(buf[1])
if ver != S5_VER || nmethods < 1 {
err = INVALID_SOCKS5_HEADER
exception.Spawn(&err, "socks: read header [% x]", buf[:2])
goto errHandler
}
buf = make([]byte, nmethods+1) // consider method non-00
setRTimeout(s.conn)
n, err = io.ReadAtLeast(s.conn, buf, nmethods)
if err != nil || n != nmethods {
err = INVALID_SOCKS5_HEADER
exception.Spawn(&err, "socks: read header [% x]", buf)
goto errHandler
}
// accept
buf = []byte{5, 0}
setWTimeout(s.conn)
_, err = s.conn.Write(buf)
if err == nil {
return true
} else {
err = exception.Spawn(&err, "socks: write response")
goto errLogging
}
errHandler:
// handshake error feedback
// NO ACCEPTABLE METHODS
buf = []byte{5, 0xff}
setWTimeout(s.conn)
s.conn.Write(buf)
errLogging:
log.Warningln(err)
return false
}
// quick resume session
func (n *d5sman) resumeSession(conn *Conn) (session *Session, err error) {
token := make([]byte, TKSZ)
setRTimeout(conn)
// just read once
nr, err := conn.Read(token)
if nr == len(token) && err == nil {
// check token ok
if session := n.sessionMgr.take(token); session != nil {
// reuse cipherFactory to init cipher
conn.SetupCipher(session.cipherFactory, token)
// identify connection
conn.SetId(session.uid, true)
return session, nil
}
}
log.Warningln("Incorrect token from", n.clientAddr, nvl(err, NULL))
return nil, VALIDATION_FAILED
}
// TODO notify peer to slow down when queue increased too fast
func (p *multiplexer) Listen(tun *Conn, handler event_handler, interval int) error {
tun.priority = &TSPriority{0, 1e9}
p.pool.Push(tun)
defer p.onTunDisconnected(tun, handler)
tun.SetSockOpt(1, 0, 1)
var (
header = make([]byte, FRAME_HEADER_LEN)
idle = NewIdler(interval, p.isClient)
router = p.router
nr int
er error
frm *frame
key string
)
if !p.isClient {
// server first ping client
// make client aware of using a valid token.
idle.ping(tun)
}
for {
idle.newRound(tun)
nr, er = io.ReadFull(tun, header)
if nr == FRAME_HEADER_LEN {
frm, er = parse_frame(header)
if er == nil && len(frm.data) > 0 {
// read All and discard tail random
nr, er = io.ReadFull(tun, frm.data)
frm.data = frm.data[:frm.length]
}
}
if er != nil {
// shutdown
if atomic.LoadInt32(&p.status) < 0 {
time.Sleep(time.Second)
return nil
}
switch idle.consumeError(er) {
case ERR_NEW_PING:
if er = idle.ping(tun); er == nil {
continue
}
case ERR_PING_TIMEOUT:
er = ex.New("Peer was unresponsive then close")
}
// abandon this connection
return er
}
// prefix tun.identifier
key = sessionKey(tun, frm.sid)
switch frm.action {
case FRAME_ACTION_CLOSE_W:
if edge, _ := router.getRegistered(key); edge != nil {
edge.bitwiseCompareAndSet(TCP_CLOSE_W)
edge.deliver(frm)
}
case FRAME_ACTION_CLOSE_R:
if edge, _ := router.getRegistered(key); edge != nil {
edge.bitwiseCompareAndSet(TCP_CLOSE_R)
closeR(edge.conn)
}
case FRAME_ACTION_DATA:
edge, pre := router.getRegistered(key)
if edge != nil {
edge.deliver(frm)
} else if pre {
router.preDeliver(key, frm)
} else {
if log.V(log.LV_WARN) {
log.Warningln("Peer sent data to an unexisted socket.", key, frm)
}
// trigger sending close to notice peer.
pack(header, FRAME_ACTION_CLOSE_R, frm.sid, nil)
if er = frameWriteBuffer(tun, header); er != nil {
return er
}
}
case FRAME_ACTION_OPEN:
router.preRegister(key)
p.wg.Add(1)
go p.connectToDest(frm, key, tun)
case FRAME_ACTION_OPEN_N, FRAME_ACTION_OPEN_Y, FRAME_ACTION_OPEN_DENIED:
edge, _ := router.getRegistered(key)
if edge != nil {
if log.V(log.LV_ACT_FRM) {
log.Infoln(p.role, "received OPEN_x", frm)
}
edge.ready <- frm.action
close(edge.ready)
} else {
if log.V(log.LV_WARN) {
log.Warningln("Peer sent OPEN_x to an unexisted socket.", key, frm)
}
}
case FRAME_ACTION_PING:
if er = idle.pong(tun); er == nil {
atomic.AddInt32(&p.pingCnt, 1)
} else { // reply pong failed
return er
}
case FRAME_ACTION_PONG:
if idle.verify() {
if p.isClient && idle.lastPing > 0 {
sRtt, devRtt := idle.updateRtt()
atomic.StoreInt32(&p.sRtt, sRtt)
if DEBUG {
log.Infof("sRtt=%d devRtt=%d", sRtt, devRtt)
if devRtt+(sRtt>>2) > sRtt {
// restart ???
log.Warningf("Network jitter sRtt=%d devRtt=%d", sRtt, devRtt)
}
}
}
} else {
log.Warningln("Incorrect action_pong received")
}
case FRAME_ACTION_TOKENS:
handler(evt_tokens, frm.data)
default: // impossible
return fmt.Errorf("Unrecognized %s", frm)
}
tun.Update()
}
}
