114 lines
2.7 KiB
Go
114 lines
2.7 KiB
Go
// Copyright (C) 2016 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package main
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import (
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"crypto/rand"
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"encoding/binary"
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"flag"
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"log"
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"strings"
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"time"
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"github.com/syncthing/syncthing/lib/beacon"
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"github.com/syncthing/syncthing/lib/discover"
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"github.com/syncthing/syncthing/lib/protocol"
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)
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var (
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all = false // print all packets, not just first from each device/source
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fake = false // send fake packets to lure out other devices faster
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mc = "[ff12::8384]:21027"
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bc = 21027
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)
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var (
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// Static prefix that we use when generating fake device IDs, so that we
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// can recognize them ourselves. Also makes the device ID start with
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// "STPROBE-" which is humanly recognizable.
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randomPrefix = []byte{148, 223, 23, 4, 148}
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// Our random, fake, device ID that we use when sending announcements.
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myID = randomDeviceID()
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)
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func main() {
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flag.BoolVar(&all, "all", all, "Print all received announcements (not only first)")
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flag.BoolVar(&fake, "fake", fake, "Send fake announcements")
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flag.StringVar(&mc, "mc", mc, "IPv6 multicast address")
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flag.IntVar(&bc, "bc", bc, "IPv4 broadcast port number")
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flag.Parse()
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if fake {
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log.Println("My ID:", myID)
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}
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runbeacon(beacon.NewMulticast(mc), fake)
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runbeacon(beacon.NewBroadcast(bc), fake)
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select {}
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}
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func runbeacon(bc beacon.Interface, fake bool) {
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go bc.Serve()
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go recv(bc)
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if fake {
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go send(bc)
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}
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}
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// receives and prints discovery announcements
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func recv(bc beacon.Interface) {
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seen := make(map[string]bool)
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for {
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data, src := bc.Recv()
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if m := binary.BigEndian.Uint32(data); m != discover.Magic {
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log.Printf("Incorrect magic %x in announcement from %v", m, src)
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continue
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}
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var ann discover.Announce
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ann.Unmarshal(data[4:])
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if ann.ID == myID {
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// This is one of our own fake packets, don't print it.
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continue
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}
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// Print announcement details for the first packet from a given
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// device ID and source address, or if -all was given.
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key := ann.ID.String() + src.String()
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if all || !seen[key] {
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log.Printf("Announcement from %v\n", src)
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log.Printf(" %v at %s\n", ann.ID, strings.Join(ann.Addresses, ", "))
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seen[key] = true
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}
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}
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}
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// sends fake discovery announcements once every second
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func send(bc beacon.Interface) {
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ann := discover.Announce{
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ID: myID,
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Addresses: []string{"tcp://fake.example.com:12345"},
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}
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bs, _ := ann.Marshal()
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for {
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bc.Send(bs)
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time.Sleep(time.Second)
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}
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}
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// returns a random but recognizable device ID
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func randomDeviceID() protocol.DeviceID {
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var id protocol.DeviceID
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copy(id[:], randomPrefix)
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rand.Read(id[len(randomPrefix):])
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return id
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}
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