mirror of
https://github.com/nadoo/glider.git
synced 2025-02-23 09:25:41 +08:00
117 lines
2.8 KiB
Go
117 lines
2.8 KiB
Go
// getOrigDst:
|
|
// https://github.com/shadowsocks/go-shadowsocks2/blob/master/tcp_linux.go#L30
|
|
|
|
package main
|
|
|
|
import (
|
|
"net"
|
|
"syscall"
|
|
"unsafe"
|
|
|
|
"github.com/shadowsocks/go-shadowsocks2/socks"
|
|
)
|
|
|
|
const (
|
|
SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv4.h
|
|
IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
|
|
)
|
|
|
|
type redir struct {
|
|
Proxy
|
|
addr string
|
|
}
|
|
|
|
// RedirProxy returns a redirect proxy.
|
|
func RedirProxy(addr string, upProxy Proxy) (Proxy, error) {
|
|
s := &redir{
|
|
Proxy: upProxy,
|
|
addr: addr,
|
|
}
|
|
|
|
return s, nil
|
|
}
|
|
|
|
// ListenAndServe redirected requests as a server.
|
|
func (s *redir) ListenAndServe() {
|
|
l, err := net.Listen("tcp", s.addr)
|
|
if err != nil {
|
|
logf("failed to listen on %s: %v", s.addr, err)
|
|
return
|
|
}
|
|
|
|
logf("listening TCP on %s", s.addr)
|
|
|
|
for {
|
|
c, err := l.Accept()
|
|
if err != nil {
|
|
logf("failed to accept: %v", err)
|
|
continue
|
|
}
|
|
|
|
go func() {
|
|
defer c.Close()
|
|
|
|
if c, ok := c.(*net.TCPConn); ok {
|
|
c.SetKeepAlive(true)
|
|
}
|
|
|
|
tgt, err := getOrigDst(c, false)
|
|
if err != nil {
|
|
logf("failed to get target address: %v", err)
|
|
return
|
|
}
|
|
|
|
rc, err := s.GetProxy().Dial("tcp", tgt.String())
|
|
if err != nil {
|
|
logf("failed to connect to target: %v", err)
|
|
return
|
|
}
|
|
defer rc.Close()
|
|
|
|
logf("proxy-redir %s <-> %s", c.RemoteAddr(), tgt)
|
|
|
|
_, _, err = relay(c, rc)
|
|
if err != nil {
|
|
if err, ok := err.(net.Error); ok && err.Timeout() {
|
|
return // ignore i/o timeout
|
|
}
|
|
logf("relay error: %v", err)
|
|
}
|
|
|
|
}()
|
|
}
|
|
}
|
|
|
|
// Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
|
|
func getorigdst(fd uintptr) (socks.Addr, error) {
|
|
raw := syscall.RawSockaddrInet4{}
|
|
siz := unsafe.Sizeof(raw)
|
|
if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
addr := make([]byte, 1+net.IPv4len+2)
|
|
addr[0] = socks.AtypIPv4
|
|
copy(addr[1:1+net.IPv4len], raw.Addr[:])
|
|
port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
|
|
addr[1+net.IPv4len], addr[1+net.IPv4len+1] = port[0], port[1]
|
|
return addr, nil
|
|
}
|
|
|
|
// Call ipv6_getorigdst() from linux/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
|
|
// NOTE: I haven't tried yet but it should work since Linux 3.8.
|
|
func ipv6_getorigdst(fd uintptr) (socks.Addr, error) {
|
|
raw := syscall.RawSockaddrInet6{}
|
|
siz := unsafe.Sizeof(raw)
|
|
if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IPV6, IP6T_SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
addr := make([]byte, 1+net.IPv6len+2)
|
|
addr[0] = socks.AtypIPv6
|
|
copy(addr[1:1+net.IPv6len], raw.Addr[:])
|
|
port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
|
|
addr[1+net.IPv6len], addr[1+net.IPv6len+1] = port[0], port[1]
|
|
return addr, nil
|
|
}
|