YTSFlix_Go/vendor/github.com/anacrolix/torrent/tracker/server.go

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2018-11-04 14:58:15 +00:00
package tracker
import (
"bytes"
"encoding"
"encoding/binary"
"fmt"
"math/rand"
"net"
"github.com/anacrolix/dht/krpc"
"github.com/anacrolix/missinggo"
)
type torrent struct {
Leechers int32
Seeders int32
Peers []krpc.NodeAddr
}
type server struct {
pc net.PacketConn
conns map[int64]struct{}
t map[[20]byte]torrent
}
func marshal(parts ...interface{}) (ret []byte, err error) {
var buf bytes.Buffer
for _, p := range parts {
err = binary.Write(&buf, binary.BigEndian, p)
if err != nil {
return
}
}
ret = buf.Bytes()
return
}
func (s *server) respond(addr net.Addr, rh ResponseHeader, parts ...interface{}) (err error) {
b, err := marshal(append([]interface{}{rh}, parts...)...)
if err != nil {
return
}
_, err = s.pc.WriteTo(b, addr)
return
}
func (s *server) newConn() (ret int64) {
ret = rand.Int63()
if s.conns == nil {
s.conns = make(map[int64]struct{})
}
s.conns[ret] = struct{}{}
return
}
func (s *server) serveOne() (err error) {
b := make([]byte, 0x10000)
n, addr, err := s.pc.ReadFrom(b)
if err != nil {
return
}
r := bytes.NewReader(b[:n])
var h RequestHeader
err = readBody(r, &h)
if err != nil {
return
}
switch h.Action {
case ActionConnect:
if h.ConnectionId != connectRequestConnectionId {
return
}
connId := s.newConn()
err = s.respond(addr, ResponseHeader{
ActionConnect,
h.TransactionId,
}, ConnectionResponse{
connId,
})
return
case ActionAnnounce:
if _, ok := s.conns[h.ConnectionId]; !ok {
s.respond(addr, ResponseHeader{
TransactionId: h.TransactionId,
Action: ActionError,
}, []byte("not connected"))
return
}
var ar AnnounceRequest
err = readBody(r, &ar)
if err != nil {
return
}
t := s.t[ar.InfoHash]
bm := func() encoding.BinaryMarshaler {
ip := missinggo.AddrIP(addr)
if ip.To4() != nil {
return krpc.CompactIPv4NodeAddrs(t.Peers)
}
return krpc.CompactIPv6NodeAddrs(t.Peers)
}()
b, err = bm.MarshalBinary()
if err != nil {
panic(err)
}
err = s.respond(addr, ResponseHeader{
TransactionId: h.TransactionId,
Action: ActionAnnounce,
}, AnnounceResponseHeader{
Interval: 900,
Leechers: t.Leechers,
Seeders: t.Seeders,
}, b)
return
default:
err = fmt.Errorf("unhandled action: %d", h.Action)
s.respond(addr, ResponseHeader{
TransactionId: h.TransactionId,
Action: ActionError,
}, []byte("unhandled action"))
return
}
}