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Copy pathredirect.go
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241 lines (199 loc) · 4.83 KB
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Copy pathredirect.go
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241 lines (199 loc) · 4.83 KB
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// +build linux
package gost
import (
"context"
"errors"
"fmt"
"net"
"sync"
"syscall"
"time"
"github.com/LiamHaworth/go-tproxy"
"github.com/go-log/log"
)
type tcpRedirectHandler struct {
options *HandlerOptions
}
// TCPRedirectHandler creates a server Handler for TCP transparent server.
func TCPRedirectHandler(opts ...HandlerOption) Handler {
h := &tcpRedirectHandler{}
h.Init(opts...)
return h
}
func (h *tcpRedirectHandler) Init(options ...HandlerOption) {
if h.options == nil {
h.options = &HandlerOptions{}
}
for _, opt := range options {
opt(h.options)
}
}
func (h *tcpRedirectHandler) Handle(c net.Conn) {
conn, ok := c.(*net.TCPConn)
if !ok {
log.Log("[red-tcp] not a TCP connection")
}
srcAddr := conn.RemoteAddr()
dstAddr, conn, err := h.getOriginalDstAddr(conn)
if err != nil {
log.Logf("[red-tcp] %s -> %s : %s", srcAddr, dstAddr, err)
return
}
defer conn.Close()
log.Logf("[red-tcp] %s -> %s", srcAddr, dstAddr)
cc, err := h.options.Chain.DialContext(context.Background(),
"tcp", dstAddr.String(),
RetryChainOption(h.options.Retries),
TimeoutChainOption(h.options.Timeout),
)
if err != nil {
log.Logf("[red-tcp] %s -> %s : %s", srcAddr, dstAddr, err)
return
}
defer cc.Close()
log.Logf("[red-tcp] %s <-> %s", srcAddr, dstAddr)
transport(conn, cc)
log.Logf("[red-tcp] %s >-< %s", srcAddr, dstAddr)
}
func (h *tcpRedirectHandler) getOriginalDstAddr(conn *net.TCPConn) (addr net.Addr, c *net.TCPConn, err error) {
defer conn.Close()
fc, err := conn.File()
if err != nil {
return
}
defer fc.Close()
mreq, err := syscall.GetsockoptIPv6Mreq(int(fc.Fd()), syscall.IPPROTO_IP, 80)
if err != nil {
return
}
// only ipv4 support
ip := net.IPv4(mreq.Multiaddr[4], mreq.Multiaddr[5], mreq.Multiaddr[6], mreq.Multiaddr[7])
port := uint16(mreq.Multiaddr[2])<<8 + uint16(mreq.Multiaddr[3])
addr, err = net.ResolveTCPAddr("tcp4", fmt.Sprintf("%s:%d", ip.String(), port))
if err != nil {
return
}
cc, err := net.FileConn(fc)
if err != nil {
return
}
c, ok := cc.(*net.TCPConn)
if !ok {
err = errors.New("not a TCP connection")
}
return
}
type udpRedirectHandler struct {
options *HandlerOptions
}
// UDPRedirectHandler creates a server Handler for UDP transparent server.
func UDPRedirectHandler(opts ...HandlerOption) Handler {
h := &udpRedirectHandler{}
h.Init(opts...)
return h
}
func (h *udpRedirectHandler) Init(options ...HandlerOption) {
if h.options == nil {
h.options = &HandlerOptions{}
}
for _, opt := range options {
opt(h.options)
}
}
func (h *udpRedirectHandler) Handle(conn net.Conn) {
defer conn.Close()
raddr, ok := conn.LocalAddr().(*net.UDPAddr)
if !ok {
log.Log("[red-udp] wrong connection type")
return
}
cc, err := h.options.Chain.DialContext(context.Background(),
"udp", raddr.String(),
RetryChainOption(h.options.Retries),
TimeoutChainOption(h.options.Timeout),
)
if err != nil {
log.Logf("[red-udp] %s - %s : %s", conn.RemoteAddr(), raddr, err)
return
}
defer cc.Close()
log.Logf("[red-udp] %s <-> %s", conn.RemoteAddr(), raddr)
transport(conn, cc)
log.Logf("[red-udp] %s >-< %s", conn.RemoteAddr(), raddr)
}
type udpRedirectListener struct {
*net.UDPConn
config *UDPListenConfig
}
// UDPRedirectListener creates a Listener for UDP transparent proxy server.
func UDPRedirectListener(addr string, cfg *UDPListenConfig) (Listener, error) {
laddr, err := net.ResolveUDPAddr("udp", addr)
if err != nil {
return nil, err
}
ln, err := tproxy.ListenUDP("udp", laddr)
if err != nil {
return nil, err
}
if cfg == nil {
cfg = &UDPListenConfig{}
}
return &udpRedirectListener{
UDPConn: ln,
config: cfg,
}, nil
}
func (l *udpRedirectListener) Accept() (conn net.Conn, err error) {
b := make([]byte, mediumBufferSize)
n, raddr, dstAddr, err := tproxy.ReadFromUDP(l.UDPConn, b)
if err != nil {
log.Logf("[red-udp] %s : %s", l.Addr(), err)
return
}
log.Logf("[red-udp] %s: %s -> %s", l.Addr(), raddr, dstAddr)
c, err := tproxy.DialUDP("udp", dstAddr, raddr)
if err != nil {
log.Logf("[red-udp] %s -> %s : %s", raddr, dstAddr, err)
return
}
ttl := l.config.TTL
if ttl <= 0 {
ttl = defaultTTL
}
conn = &udpRedirectServerConn{
Conn: c,
buf: b[:n],
ttl: ttl,
}
return
}
func (l *udpRedirectListener) Addr() net.Addr {
return l.UDPConn.LocalAddr()
}
type udpRedirectServerConn struct {
net.Conn
buf []byte
ttl time.Duration
once sync.Once
}
func (c *udpRedirectServerConn) Read(b []byte) (n int, err error) {
if c.ttl > 0 {
c.SetReadDeadline(time.Now().Add(c.ttl))
defer c.SetReadDeadline(time.Time{})
}
c.once.Do(func() {
n = copy(b, c.buf)
c.buf = nil
})
if n == 0 {
n, err = c.Conn.Read(b)
}
return
}
func (c *udpRedirectServerConn) Write(b []byte) (n int, err error) {
if c.ttl > 0 {
c.SetWriteDeadline(time.Now().Add(c.ttl))
defer c.SetWriteDeadline(time.Time{})
}
return c.Conn.Write(b)
}