torrent/cmd/dht-get-peers/main.go

164 lines
3.3 KiB
Go

package main
import (
"flag"
"fmt"
"io"
"log"
"net"
"os"
"os/signal"
_ "github.com/anacrolix/envpprof"
"github.com/anacrolix/torrent/dht"
)
var (
tableFileName = flag.String("tableFile", "", "name of file for storing node info")
serveAddr = flag.String("serveAddr", ":0", "local UDP address")
infoHash = flag.String("infoHash", "", "torrent infohash")
once = flag.Bool("once", false, "only do one scrape iteration")
s *dht.Server
quitting = make(chan struct{})
)
func loadTable() error {
if *tableFileName == "" {
return nil
}
f, err := os.Open(*tableFileName)
if os.IsNotExist(err) {
return nil
}
if err != nil {
return fmt.Errorf("error opening table file: %s", err)
}
defer f.Close()
added := 0
for {
b := make([]byte, dht.CompactIPv4NodeInfoLen)
_, err := io.ReadFull(f, b)
if err == io.EOF {
break
}
if err != nil {
return fmt.Errorf("error reading table file: %s", err)
}
var ni dht.NodeInfo
err = ni.UnmarshalCompactIPv4(b)
if err != nil {
return fmt.Errorf("error unmarshaling compact node info: %s", err)
}
s.AddNode(ni)
added++
}
log.Printf("loaded %d nodes from table file", added)
return nil
}
func init() {
log.SetFlags(log.LstdFlags | log.Lshortfile)
flag.Parse()
switch len(*infoHash) {
case 20:
case 40:
_, err := fmt.Sscanf(*infoHash, "%x", infoHash)
if err != nil {
log.Fatal(err)
}
default:
log.Fatal("require 20 byte infohash")
}
var err error
s, err = dht.NewServer(&dht.ServerConfig{
Addr: *serveAddr,
})
if err != nil {
log.Fatal(err)
}
err = loadTable()
if err != nil {
log.Fatalf("error loading table: %s", err)
}
log.Printf("dht server on %s, ID is %x", s.Addr(), s.ID())
setupSignals()
}
func saveTable() error {
goodNodes := s.Nodes()
if *tableFileName == "" {
if len(goodNodes) != 0 {
log.Print("good nodes were discarded because you didn't specify a table file")
}
return nil
}
f, err := os.OpenFile(*tableFileName, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0666)
if err != nil {
return fmt.Errorf("error opening table file: %s", err)
}
defer f.Close()
for _, nodeInfo := range goodNodes {
var b [dht.CompactIPv4NodeInfoLen]byte
err := nodeInfo.PutCompact(b[:])
if err != nil {
return fmt.Errorf("error compacting node info: %s", err)
}
_, err = f.Write(b[:])
if err != nil {
return fmt.Errorf("error writing compact node info: %s", err)
}
}
log.Printf("saved %d nodes to table file", len(goodNodes))
return nil
}
func setupSignals() {
ch := make(chan os.Signal)
signal.Notify(ch, os.Interrupt)
go func() {
<-ch
close(quitting)
}()
}
func main() {
seen := make(map[string]struct{})
getPeers:
for {
ps, err := s.Announce(*infoHash, 0, false)
if err != nil {
log.Fatal(err)
}
values:
for {
select {
case v, ok := <-ps.Peers:
if !ok {
break values
}
log.Printf("received %d peers from %x", len(v.Peers), v.NodeInfo.ID)
for _, p := range v.Peers {
if _, ok := seen[p.String()]; ok {
continue
}
seen[p.String()] = struct{}{}
fmt.Println((&net.UDPAddr{
IP: p.IP[:],
Port: int(p.Port),
}).String())
}
case <-quitting:
break getPeers
}
}
if *once {
break
}
}
if err := saveTable(); err != nil {
log.Printf("error saving node table: %s", err)
}
}