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