117 lines
2.4 KiB
Go
117 lines
2.4 KiB
Go
// Copyright Safing ICS Technologies GmbH. Use of this source code is governed by the AGPL license that can be found in the LICENSE file.
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package environment
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import (
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"errors"
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"fmt"
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"log"
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"net"
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"os"
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"time"
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"github.com/Safing/portmaster/network/netutils"
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"golang.org/x/net/icmp"
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"golang.org/x/net/ipv4"
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)
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// TODO: reference forking
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// TODO: Create IPv6 version of GetApproximateInternetLocation
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// GetApproximateInternetLocation returns the IP-address of the nearest ping-answering internet node
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func GetApproximateInternetLocation() (net.IP, error) {
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// TODO: first check if we have a public IP
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// net.InterfaceAddrs()
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// Traceroute example
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var dst net.IPAddr
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dst.IP = net.IPv4(8, 8, 8, 8)
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c, err := net.ListenPacket("ip4:1", "0.0.0.0") // ICMP for IPv4
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if err != nil {
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return nil, err
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}
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defer c.Close()
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p := ipv4.NewPacketConn(c)
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err = p.SetControlMessage(ipv4.FlagTTL|ipv4.FlagSrc|ipv4.FlagDst|ipv4.FlagInterface, true)
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if err != nil {
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return nil, err
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}
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wm := icmp.Message{
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Type: ipv4.ICMPTypeEcho, Code: 0,
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Body: &icmp.Echo{
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ID: os.Getpid() & 0xffff,
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// TODO: think of something better and not suspicious
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Data: []byte("HELLO-R-U-THERE"),
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},
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}
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rb := make([]byte, 1500)
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next:
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for i := 1; i <= 64; i++ { // up to 64 hops
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repeat:
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for j := 1; j <= 5; j++ {
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wm.Body.(*icmp.Echo).Seq = i
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wb, err := wm.Marshal(nil)
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if err != nil {
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return nil, err
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}
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err = p.SetTTL(i)
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if err != nil {
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return nil, err
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}
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_, err = p.WriteTo(wb, nil, &dst)
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if err != nil {
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return nil, err
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}
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err = p.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
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if err != nil {
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return nil, err
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}
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// n, cm, peer, err := p.ReadFrom(rb)
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// readping:
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for {
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n, _, peer, err := p.ReadFrom(rb)
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if err != nil {
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if err, ok := err.(net.Error); ok && err.Timeout() {
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continue repeat
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}
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return nil, err
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}
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rm, err := icmp.ParseMessage(1, rb[:n])
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if err != nil {
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log.Fatal(err)
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}
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switch rm.Type {
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case ipv4.ICMPTypeTimeExceeded:
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ip := net.ParseIP(peer.String())
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if ip == nil {
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return nil, errors.New(fmt.Sprintf("failed to parse IP: %s", peer.String()))
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}
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if !netutils.IPIsLAN(ip) {
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return ip, nil
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}
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continue next
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case ipv4.ICMPTypeEchoReply:
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continue next
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default:
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// log.Tracef("unknown ICMP message: %+v\n", rm)
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}
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}
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}
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}
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return nil, nil
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}
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