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Copy pathrelay.go
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354 lines (313 loc) · 7.32 KB
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package gost
import (
"bytes"
"context"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"net/url"
"strconv"
"sync"
"time"
"github.com/go-gost/relay"
"github.com/go-log/log"
)
type relayConnector struct {
user *url.Userinfo
remoteAddr string
}
// RelayConnector creates a Connector for TCP/UDP data relay.
func RelayConnector(user *url.Userinfo) Connector {
return &relayConnector{
user: user,
}
}
func (c *relayConnector) Connect(conn net.Conn, address string, options ...ConnectOption) (net.Conn, error) {
return conn, nil
}
func (c *relayConnector) ConnectContext(ctx context.Context, conn net.Conn, network, address string, options ...ConnectOption) (net.Conn, error) {
opts := &ConnectOptions{}
for _, option := range options {
option(opts)
}
timeout := opts.Timeout
if timeout <= 0 {
timeout = ConnectTimeout
}
conn.SetDeadline(time.Now().Add(timeout))
defer conn.SetDeadline(time.Time{})
var udp bool
if network == "udp" || network == "udp4" || network == "udp6" {
udp = true
}
req := &relay.Request{
Version: relay.Version1,
}
if udp {
req.Flags |= relay.FUDP
}
if c.user != nil {
pwd, _ := c.user.Password()
req.Features = append(req.Features, &relay.UserAuthFeature{
Username: c.user.Username(),
Password: pwd,
})
}
if address != "" {
host, port, _ := net.SplitHostPort(address)
nport, _ := strconv.ParseUint(port, 10, 16)
if host == "" {
host = net.IPv4zero.String()
}
if nport > 0 {
var atype uint8
ip := net.ParseIP(host)
if ip == nil {
atype = relay.AddrDomain
} else if ip.To4() == nil {
atype = relay.AddrIPv6
} else {
atype = relay.AddrIPv4
}
req.Features = append(req.Features, &relay.TargetAddrFeature{
AType: atype,
Host: host,
Port: uint16(nport),
})
}
}
rc := &relayConn{
udp: udp,
Conn: conn,
}
// write the header at once.
if opts.NoDelay {
if _, err := req.WriteTo(rc); err != nil {
return nil, err
}
} else {
if _, err := req.WriteTo(&rc.wbuf); err != nil {
return nil, err
}
}
return rc, nil
}
type relayHandler struct {
*baseForwardHandler
}
// RelayHandler creates a server Handler for TCP/UDP relay server.
func RelayHandler(raddr string, opts ...HandlerOption) Handler {
h := &relayHandler{
baseForwardHandler: &baseForwardHandler{
raddr: raddr,
group: NewNodeGroup(),
options: &HandlerOptions{},
},
}
for _, opt := range opts {
opt(h.options)
}
return h
}
func (h *relayHandler) Init(options ...HandlerOption) {
h.baseForwardHandler.Init(options...)
}
func (h *relayHandler) Handle(conn net.Conn) {
defer conn.Close()
req := &relay.Request{}
if _, err := req.ReadFrom(conn); err != nil {
log.Logf("[relay] %s - %s : %s", conn.RemoteAddr(), conn.LocalAddr(), err)
return
}
if req.Version != relay.Version1 {
log.Logf("[relay] %s - %s : bad version", conn.RemoteAddr(), conn.LocalAddr())
return
}
var user, pass string
var raddr string
for _, f := range req.Features {
if f.Type() == relay.FeatureUserAuth {
feature := f.(*relay.UserAuthFeature)
user, pass = feature.Username, feature.Password
}
if f.Type() == relay.FeatureTargetAddr {
feature := f.(*relay.TargetAddrFeature)
raddr = net.JoinHostPort(feature.Host, strconv.Itoa(int(feature.Port)))
}
}
resp := &relay.Response{
Version: relay.Version1,
Status: relay.StatusOK,
}
if h.options.Authenticator != nil && !h.options.Authenticator.Authenticate(user, pass) {
resp.Status = relay.StatusUnauthorized
resp.WriteTo(conn)
log.Logf("[relay] %s -> %s : %s unauthorized", conn.RemoteAddr(), conn.LocalAddr(), user)
return
}
if raddr != "" {
if len(h.group.Nodes()) > 0 {
resp.Status = relay.StatusForbidden
resp.WriteTo(conn)
log.Logf("[relay] %s -> %s : relay to %s is forbidden",
conn.RemoteAddr(), conn.LocalAddr(), raddr)
return
}
} else {
if len(h.group.Nodes()) == 0 {
resp.Status = relay.StatusBadRequest
resp.WriteTo(conn)
log.Logf("[relay] %s -> %s : bad request, target addr is needed",
conn.RemoteAddr(), conn.LocalAddr())
return
}
}
udp := (req.Flags & relay.FUDP) == relay.FUDP
retries := 1
if h.options.Chain != nil && h.options.Chain.Retries > 0 {
retries = h.options.Chain.Retries
}
if h.options.Retries > 0 {
retries = h.options.Retries
}
network := "tcp"
if udp {
network = "udp"
}
ctx := context.TODO()
var cc net.Conn
var node Node
var err error
for i := 0; i < retries; i++ {
if len(h.group.Nodes()) > 0 {
node, err = h.group.Next()
if err != nil {
resp.Status = relay.StatusServiceUnavailable
resp.WriteTo(conn)
log.Logf("[relay] %s - %s : %s", conn.RemoteAddr(), conn.LocalAddr(), err)
return
}
raddr = node.Addr
}
log.Logf("[relay] %s -> %s -> %s", conn.RemoteAddr(), conn.LocalAddr(), raddr)
cc, err = h.options.Chain.DialContext(ctx,
network, raddr,
RetryChainOption(h.options.Retries),
TimeoutChainOption(h.options.Timeout),
)
if err != nil {
log.Logf("[relay] %s -> %s : %s", conn.RemoteAddr(), raddr, err)
node.MarkDead()
} else {
break
}
}
if err != nil {
resp.Status = relay.StatusServiceUnavailable
resp.WriteTo(conn)
return
}
node.ResetDead()
defer cc.Close()
sc := &relayConn{
Conn: conn,
isServer: true,
udp: udp,
}
resp.WriteTo(&sc.wbuf)
conn = sc
log.Logf("[relay] %s <-> %s", conn.RemoteAddr(), raddr)
transport(conn, cc)
log.Logf("[relay] %s >-< %s", conn.RemoteAddr(), raddr)
}
type relayConn struct {
net.Conn
isServer bool
udp bool
wbuf bytes.Buffer
once sync.Once
}
func (c *relayConn) Read(b []byte) (n int, err error) {
c.once.Do(func() {
if c.isServer {
return
}
resp := new(relay.Response)
_, err = resp.ReadFrom(c.Conn)
if err != nil {
return
}
if resp.Version != relay.Version1 {
err = relay.ErrBadVersion
return
}
if resp.Status != relay.StatusOK {
err = fmt.Errorf("status %d", resp.Status)
return
}
})
if err != nil {
log.Logf("[relay] %s <- %s: %s", c.Conn.LocalAddr(), c.Conn.RemoteAddr(), err)
return
}
if !c.udp {
return c.Conn.Read(b)
}
var bb [2]byte
_, err = io.ReadFull(c.Conn, bb[:])
if err != nil {
return
}
dlen := int(binary.BigEndian.Uint16(bb[:]))
if len(b) >= dlen {
return io.ReadFull(c.Conn, b[:dlen])
}
buf := make([]byte, dlen)
_, err = io.ReadFull(c.Conn, buf)
n = copy(b, buf)
return
}
func (c *relayConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
n, err = c.Read(b)
addr = c.Conn.RemoteAddr()
return
}
func (c *relayConn) Write(b []byte) (n int, err error) {
if len(b) > 0xFFFF {
err = errors.New("write: data maximum exceeded")
return
}
n = len(b) // force byte length consistent
if c.wbuf.Len() > 0 {
if c.udp {
var bb [2]byte
binary.BigEndian.PutUint16(bb[:2], uint16(len(b)))
c.wbuf.Write(bb[:])
}
c.wbuf.Write(b) // append the data to the cached header
// _, err = c.Conn.Write(c.wbuf.Bytes())
// c.wbuf.Reset()
_, err = c.wbuf.WriteTo(c.Conn)
return
}
if !c.udp {
return c.Conn.Write(b)
}
nsize := 2 + len(b)
var buf []byte
if nsize <= mediumBufferSize {
buf = mPool.Get().([]byte)
defer mPool.Put(buf)
} else {
buf = make([]byte, nsize)
}
binary.BigEndian.PutUint16(buf[:2], uint16(len(b)))
n = copy(buf[2:], b)
_, err = c.Conn.Write(buf[:nsize])
return
}
func (c *relayConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
return c.Write(b)
}