mirror of https://github.com/v2ray/v2ray-core
42 lines
1.1 KiB
Go
42 lines
1.1 KiB
Go
// +build linux
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package tcp
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import (
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"syscall"
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"v2ray.com/core/common/net"
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"v2ray.com/core/transport/internet"
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)
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const SO_ORIGINAL_DST = 80
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func GetOriginalDestination(conn internet.Connection) (net.Destination, error) {
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sysrawconn, f := conn.(syscall.Conn)
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if !f {
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return net.Destination{}, newError("unable to get syscall.Conn")
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}
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rawConn, err := sysrawconn.SyscallConn()
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if err != nil {
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return net.Destination{}, newError("failed to get sys fd").Base(err)
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}
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var dest net.Destination
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err = rawConn.Control(func(fd uintptr) {
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addr, err := syscall.GetsockoptIPv6Mreq(int(fd), syscall.IPPROTO_IP, SO_ORIGINAL_DST)
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if err != nil {
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newError("failed to call getsockopt").Base(err).WriteToLog()
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return
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}
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ip := net.IPAddress(addr.Multiaddr[4:8])
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port := uint16(addr.Multiaddr[2])<<8 + uint16(addr.Multiaddr[3])
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dest = net.TCPDestination(ip, net.Port(port))
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})
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if err != nil {
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return net.Destination{}, newError("failed to control connection").Base(err)
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}
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if !dest.IsValid() {
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return net.Destination{}, newError("failed to call getsockopt")
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}
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return dest, nil
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}
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