69 lines
1.8 KiB
Go
69 lines
1.8 KiB
Go
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package server
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/**
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* WARNING WARNING WARNING
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* This file contains MANY DIRTY HACKS, and most of them made much assume to go internal code layout.
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* For every new go version, you MUST try to use every function, make sure they didn't panic for you.
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*/
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// WARZONE BEGINS HERE! MIND YOUR HEAD!
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import (
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"reflect"
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"net"
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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
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)
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func GetFDFromTCPConn(conn *net.TCPConn) int {
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// Actual fd is stored at: (*(*TCPConn).conn.fd).sysfd
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v := reflect.ValueOf(*conn)
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c := v.FieldByName("conn")
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fdp := c.FieldByName("fd")
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fd := reflect.Indirect(fdp)
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sysfd := fd.FieldByName("sysfd")
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return int(sysfd.Int())
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}
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func GetAddr4FromFD(fd int) *net.TCPAddr {
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mtuinfo, err := unix.GetsockoptIPv6MTUInfo(fd, unix.IPPROTO_IP, SO_ORIGINAL_DST)
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if err != nil {
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panic(err)
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}
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addr := mtuinfo.Addr
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/*
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RawSockaddrInet6 layout:
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Family 2byte ignore or assert == AF_INET
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Port 2byte ipv4 port
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Flowinfo 4byte ipv4 address
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Addr 16byte ignore for ipv4
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Scope_id 4byte ignore for ipv4
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*/
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addr.Flowinfo = be32toh(addr.Flowinfo)
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a, b, c, d := byte(addr.Flowinfo >> 24), byte((addr.Flowinfo >> 16) & 255), byte((addr.Flowinfo >> 8) & 255), byte(addr.Flowinfo & 255)
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ip := net.IPv4(a, b, c, d)
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return &net.TCPAddr{IP: ip, Port: int(be16toh(addr.Port)), Zone: ""}
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}
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func GetAddr6FromFD(fd int) *net.TCPAddr {
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mtuinfo, err := unix.GetsockoptIPv6MTUInfo(fd, unix.IPPROTO_IPV6, SO_ORIGINAL_DST)
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if err != nil {
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panic(err)
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}
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addr := mtuinfo.Addr
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/*
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RawSockaddrInet6 layout:
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Family 2byte ignore or assert == AF_INET6
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Port 2byte ipv6 port
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Flowinfo 4byte ipv6 flowinfo ignore
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Addr 16byte ipv6 addr
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Scope_id 4byte ipv6 scope id ignore
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*/
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v6addr := make(net.IP, 16)
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// Make GC happy?
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copy(v6addr, addr.Addr[:])
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return &net.TCPAddr{IP: v6addr, Port: int(be16toh(addr.Port)), Zone: ""}
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}
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