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https://github.com/MetaCubeX/mihomo.git
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64 lines
1.8 KiB
Go
64 lines
1.8 KiB
Go
package redir
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import (
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"encoding/binary"
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"errors"
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"net"
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"net/netip"
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"syscall"
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"unsafe"
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"github.com/Dreamacro/clash/transport/socks5"
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"golang.org/x/sys/unix"
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)
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const (
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SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv4.h
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IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
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)
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func parserPacket(conn net.Conn) (socks5.Addr, error) {
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c, ok := conn.(*net.TCPConn)
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if !ok {
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return nil, errors.New("only work with TCP connection")
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}
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rc, err := c.SyscallConn()
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if err != nil {
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return nil, err
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}
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var addr netip.AddrPort
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rc.Control(func(fd uintptr) {
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if ip4 := c.LocalAddr().(*net.TCPAddr).IP.To4(); ip4 != nil {
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addr, err = getorigdst(fd)
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} else {
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addr, err = getorigdst6(fd)
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}
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})
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return socks5.AddrFromStdAddrPort(addr), err
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}
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// Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
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func getorigdst(fd uintptr) (netip.AddrPort, error) {
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addr := unix.RawSockaddrInet4{}
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size := uint32(unsafe.Sizeof(addr))
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if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&addr)), uintptr(unsafe.Pointer(&size)), 0); err != nil {
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return netip.AddrPort{}, err
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}
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port := binary.BigEndian.Uint16((*(*[2]byte)(unsafe.Pointer(&addr.Port)))[:])
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return netip.AddrPortFrom(netip.AddrFrom4(addr.Addr), port), nil
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}
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func getorigdst6(fd uintptr) (netip.AddrPort, error) {
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addr := unix.RawSockaddrInet6{}
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size := uint32(unsafe.Sizeof(addr))
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if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IPV6, IP6T_SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&addr)), uintptr(unsafe.Pointer(&size)), 0); err != nil {
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return netip.AddrPort{}, err
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}
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port := binary.BigEndian.Uint16((*(*[2]byte)(unsafe.Pointer(&addr.Port)))[:])
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return netip.AddrPortFrom(netip.AddrFrom16(addr.Addr), port), nil
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}
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