mirror of
https://github.com/GopeedLab/gopeed.git
synced 2026-11-05 16:15:43 +00:00
431 lines
11 KiB
Go
431 lines
11 KiB
Go
package tracker
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"math"
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mrand "math/rand"
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"net"
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"net/http"
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"net/url"
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"strconv"
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"sync"
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"time"
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"github.com/monkeyWie/gopeed/protocol/bt/metainfo"
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"github.com/monkeyWie/gopeed/protocol/bt/peer"
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)
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const (
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udpConnectRequestMagic = 0x41727101980
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udpConnectTimeout = 15
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udpConnectRetries = 3
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udpActionConnect = 0
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udpActionAnnounce = 1
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udpActionScrape = 2
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udpActionError = 3
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)
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/*
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Offset size Name Value
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0 64-bit integer protocol_id 0x41727101980 // magic constant
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8 32-bit integer action 0 // connect
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12 32-bit integer transaction_id
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16
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Per https://www.libtorrent.org/udp_tracker_protocol.html#connecting
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*/
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type udpConnectRequest struct {
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protocolId uint64
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action uint32
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transactionId uint32
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}
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func newUdpConnectRequest() *udpConnectRequest {
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return &udpConnectRequest{
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protocolId: udpConnectRequestMagic,
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action: udpActionConnect,
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transactionId: mrand.Uint32(),
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}
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}
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func (req *udpConnectRequest) encode() []byte {
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buf := make([]byte, 16)
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binary.BigEndian.PutUint64(buf[:8], req.protocolId)
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binary.BigEndian.PutUint32(buf[8:12], req.action)
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binary.BigEndian.PutUint32(buf[12:], req.transactionId)
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return buf
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}
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/*
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Offset size Name Value
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0 32-bit integer action 0 // connect
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4 32-bit integer transaction_id
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8 64-bit integer connection_id
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16
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*/
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type udpConnectResponse struct {
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action uint32
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transactionId uint32
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connectionId uint64
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}
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func newUdpConnectResponse(buf []byte) *udpConnectResponse {
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return &udpConnectResponse{
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action: binary.BigEndian.Uint32(buf[:4]),
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transactionId: binary.BigEndian.Uint32(buf[4:8]),
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connectionId: binary.BigEndian.Uint64(buf[8:]),
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}
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}
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/*
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Offset size Name Value
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0 64-bit integer connection_id
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8 32-bit integer action 1 // announce
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12 32-bit integer transaction_id
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16 20-byte string info_hash
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36 20-byte string peer_id
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56 64-bit integer downloaded
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64 64-bit integer left
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72 64-bit integer uploaded
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80 32-bit integer event 0 // 0: none; 1: completed; 2: started; 3: stopped
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84 32-bit integer ip address 0 // default
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88 32-bit integer key
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92 32-bit integer num_want -1 // default
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96 16-bit integer port
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98
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Per https://www.libtorrent.org/udp_tracker_protocol.html#announcing
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*/
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type udpAnnounceRequest struct {
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connectionId uint64
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action uint32
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transactionId uint32
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infoHash [20]byte
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peerID [20]byte
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downloaded uint64
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left uint64
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uploaded uint64
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event uint32
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ip uint32
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key uint32
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numWant uint32
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port uint16
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}
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func newUdpAnnounceRequest(connectionId uint64) *udpAnnounceRequest {
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return &udpAnnounceRequest{
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connectionId: connectionId,
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action: udpActionAnnounce,
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transactionId: mrand.Uint32(),
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}
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}
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func (req *udpAnnounceRequest) encode() []byte {
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buf := make([]byte, 98, 98)
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binary.BigEndian.PutUint64(buf[:8], req.connectionId)
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binary.BigEndian.PutUint32(buf[8:12], req.action)
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binary.BigEndian.PutUint32(buf[12:16], req.transactionId)
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copy(buf[16:36], req.infoHash[:])
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copy(buf[36:56], req.peerID[:])
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binary.BigEndian.PutUint64(buf[56:64], req.downloaded)
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binary.BigEndian.PutUint64(buf[64:72], req.left)
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binary.BigEndian.PutUint64(buf[72:80], req.uploaded)
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binary.BigEndian.PutUint32(buf[80:84], req.event)
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binary.BigEndian.PutUint32(buf[84:88], req.ip)
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binary.BigEndian.PutUint32(buf[88:92], req.key)
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binary.BigEndian.PutUint32(buf[92:96], req.numWant)
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binary.BigEndian.PutUint16(buf[96:98], req.port)
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return buf
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}
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/*
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Offset size Name Value
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0 32-bit integer action 1 // announce
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4 32-bit integer transaction_id
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8 32-bit integer interval
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12 32-bit integer leechers
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16 32-bit integer seeders
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20 + 6 * n 32-bit integer ip address
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24 + 6 * n 16-bit integer TCP port
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20 + 6 * N
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Per https://www.libtorrent.org/udp_tracker_protocol.html#announcing
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*/
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type udpAnnounceResponse struct {
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action uint32
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transactionId uint32
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interval uint32
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leechers uint32
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seeders uint32
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peers []peer.Peer
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}
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func newUdpAnnounceResponse(buf []byte) *udpAnnounceResponse {
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response := &udpAnnounceResponse{
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action: binary.BigEndian.Uint32(buf[:4]),
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transactionId: binary.BigEndian.Uint32(buf[4:8]),
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interval: binary.BigEndian.Uint32(buf[8:12]),
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leechers: binary.BigEndian.Uint32(buf[12:16]),
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seeders: binary.BigEndian.Uint32(buf[16:20]),
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}
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count := (len(buf) - 20) / 6
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response.peers = make([]peer.Peer, count, count)
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for i := 0; i < count; i++ {
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ipBegin := 20 + 6*i
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portBegin := ipBegin + 4
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response.peers[i] = peer.Peer{
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IP: binary.BigEndian.Uint32(buf[ipBegin:portBegin]),
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Port: binary.BigEndian.Uint16(buf[portBegin : portBegin+2]),
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}
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}
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return response
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}
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type Tracker struct {
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PeerID [20]byte
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MetaInfo *metainfo.MetaInfo
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}
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func (tracker *Tracker) connect(conn *net.UDPConn, timeout int64) (response *udpConnectResponse, err error) {
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request := newUdpConnectRequest()
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buf := request.encode()
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conn.SetReadDeadline(time.Now().Add(time.Second * time.Duration(timeout)))
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conn.Write(buf)
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len, err := conn.Read(buf)
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if err != nil {
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return
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}
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if len != 16 {
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err = NewTrackerError(ErrResponse, errors.New("invalid response"))
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return
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}
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response = newUdpConnectResponse(buf)
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return
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}
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func (tracker *Tracker) announce(conn *net.UDPConn, timeout int64, connectionId uint64) (response *udpAnnounceResponse, err error) {
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request := newUdpAnnounceRequest(connectionId)
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request.infoHash = tracker.MetaInfo.GetInfoHash()
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request.peerID = tracker.PeerID
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request.downloaded = 0
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request.uploaded = 0
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request.left = tracker.MetaInfo.GetTotalSize() - request.downloaded
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request.event = 0
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request.ip = 0
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request.key = 0
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request.numWant = 200
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request.port = 6882
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encode := request.encode()
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conn.SetReadDeadline(time.Now().Add(time.Second * time.Duration(timeout)))
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conn.Write(encode)
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buf := make([]byte, 20+request.numWant*6)
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len, err := conn.Read(buf)
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if err != nil {
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return
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}
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if len < 20 {
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err = errors.New("announce fail")
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return
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}
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response = newUdpAnnounceResponse(buf[:len])
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return
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}
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// 通过tracker服务器获取peer信息
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func (tracker *Tracker) Tracker() <-chan []peer.Peer {
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peersCh := make(chan []peer.Peer)
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metaInfo := tracker.MetaInfo
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checkAnnounceList := func(announceList [][]string) bool {
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if len(announceList) > 0 {
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for _, l := range announceList {
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if len(l) > 0 {
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return true
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}
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}
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}
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return false
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}
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// 只要获取到了peers就直接返回
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if checkAnnounceList(metaInfo.AnnounceList) {
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wg := sync.WaitGroup{}
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for _, announceArr := range metaInfo.AnnounceList {
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if len(announceArr) > 0 {
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for _, announce := range announceArr {
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wg.Add(1)
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go func(announce string) {
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peers, err := tracker.DoTracker(announce)
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if err == nil {
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peersCh <- peers
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}
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wg.Done()
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}(announce)
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}
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}
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}
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go func() {
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wg.Wait()
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close(peersCh)
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}()
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} else {
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go func() {
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peers, err := tracker.DoTracker(metaInfo.Announce)
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if err == nil {
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peersCh <- peers
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}
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close(peersCh)
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}()
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}
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return peersCh
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}
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func (tracker *Tracker) DoTracker(announce string) (peers []peer.Peer, err error) {
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if announce != "" {
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url, _ := url.Parse(announce)
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switch url.Scheme {
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case "http", "https":
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return tracker.httpTracker(url)
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case "udp", "udp4", "udp6":
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return tracker.udpTracker(url)
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default:
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return nil, errors.New("unsupported protocol")
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}
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}
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return nil, errors.New("empty announce")
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}
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// http://bittorrent.org/beps/bep_0003.html#trackers
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func (tracker *Tracker) httpTracker(url *url.URL) (peers []peer.Peer, err error) {
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metaInfo := tracker.MetaInfo
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peerID := tracker.PeerID
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query := url.Query()
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infoHash := metaInfo.GetInfoHash()
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query.Add("info_hash", string(infoHash[:]))
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query.Add("peer_id", string(peerID[:]))
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query.Add("port", "6882")
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query.Add("uploaded", "0")
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query.Add("downloaded", "0")
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query.Add("left", strconv.FormatInt(int64(metaInfo.GetTotalSize()), 10))
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url.RawQuery = query.Encode()
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request, err := http.NewRequest("GET", url.String(), nil)
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if err != nil {
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return
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}
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var httpClient = &http.Client{
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Timeout: time.Second * time.Duration(15),
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}
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request.Header.Set("User-Agent", "gopeed/0.0.1")
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response, err := httpClient.Do(request)
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if err != nil {
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return
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}
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defer response.Body.Close()
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resp, err := ioutil.ReadAll(response.Body)
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if err != nil {
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if err != io.EOF {
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return
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}
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}
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// TODO Parse HTTP tracker response
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fmt.Println(resp)
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return nil, nil
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}
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// http://bittorrent.org/beps/bep_0015.html
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func (tracker *Tracker) udpTracker(url *url.URL) (peers []peer.Peer, err error) {
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conn, err := dial(url)
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if err != nil {
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return
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}
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defer conn.Close()
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announceResponse, err := func() (announceResponse *udpAnnounceResponse, err error) {
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var connectResponse *udpConnectResponse
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// 0:connect 1:announce
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state := udpActionConnect
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// 访问超时最多重试8次，当有请求成功则将重试次数重置为0
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for n := 0; n < udpConnectRetries; n++ {
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// 15 * 2 ^ n seconds
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timeout := int64(udpConnectTimeout * math.Pow(2, float64(n)))
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switch state {
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case udpActionConnect:
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connectResponse, err = tracker.connect(conn, timeout)
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if err != nil {
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if oe, ok := err.(*net.OpError); ok && oe.Timeout() {
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break
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} else {
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return
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}
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}
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n = -1
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state = udpActionAnnounce
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break
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case udpActionAnnounce:
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announceResponse, err = tracker.announce(conn, timeout, connectResponse.connectionId)
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if err != nil {
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if oe, ok := err.(*net.OpError); ok && oe.Timeout() {
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break
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} else {
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return
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}
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}
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return
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}
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}
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return
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}()
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if err != nil {
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return
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}
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return announceResponse.peers, nil
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}
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func dial(trackerUrl *url.URL) (*net.UDPConn, error) {
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host, portStr, err := net.SplitHostPort(trackerUrl.Host)
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if err != nil {
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return nil, err
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}
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port, err := strconv.ParseInt(portStr, 10, 32)
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if err != nil {
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return nil, err
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}
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ip, err := lookupIP(host, trackerUrl.Scheme)
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if err != nil {
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return nil, err
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}
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srcAddr := &net.UDPAddr{IP: net.IPv4zero, Port: 0}
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dstAddr := &net.UDPAddr{
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IP: ip,
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Port: int(port),
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}
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return net.DialUDP(trackerUrl.Scheme, srcAddr, dstAddr)
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}
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func lookupIP(host string, scheme string) (ip net.IP, err error) {
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ips, _ := net.LookupIP(host)
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if len(ips) == 0 {
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err = errors.New("no ips")
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return
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}
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for _, ip = range ips {
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switch scheme {
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case "udp", "udp4":
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if ip.To4() != nil {
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return
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}
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case "udp6":
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if ip.To4() == nil {
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return
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}
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}
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}
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err = errors.New("no available ips ")
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return
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}
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