tracker/http.go

   1 package tracker
   2
   3 import (
   4         "bytes"
   5         "crypto/tls"
   6         "fmt"
   7         "io"
   8         "math"
   9         "net"
  10         "net/http"
  11         "net/url"
  12         "strconv"
  13         "time"
  14
  15         "github.com/anacrolix/dht/v2/krpc"
  16         "github.com/anacrolix/missinggo/httptoo"
  17
  18         "github.com/anacrolix/torrent/bencode"
  19 )
  20
  21 type HttpResponse struct {
  22         FailureReason string `bencode:"failure reason"`
  23         Interval      int32  `bencode:"interval"`
  24         TrackerId     string `bencode:"tracker id"`
  25         Complete      int32  `bencode:"complete"`
  26         Incomplete    int32  `bencode:"incomplete"`
  27         Peers         Peers  `bencode:"peers"`
  28         // BEP 7
  29         Peers6 krpc.CompactIPv6NodeAddrs `bencode:"peers6"`
  30 }
  31
  32 type Peers []Peer
  33
  34 func (me *Peers) UnmarshalBencode(b []byte) (err error) {
  35         var _v interface{}
  36         err = bencode.Unmarshal(b, &_v)
  37         if err != nil {
  38                 return
  39         }
  40         switch v := _v.(type) {
  41         case string:
  42                 vars.Add("http responses with string peers", 1)
  43                 var cnas krpc.CompactIPv4NodeAddrs
  44                 err = cnas.UnmarshalBinary([]byte(v))
  45                 if err != nil {
  46                         return
  47                 }
  48                 for _, cp := range cnas {
  49                         *me = append(*me, Peer{
  50                                 IP:   cp.IP[:],
  51                                 Port: int(cp.Port),
  52                         })
  53                 }
  54                 return
  55         case []interface{}:
  56                 vars.Add("http responses with list peers", 1)
  57                 for _, i := range v {
  58                         var p Peer
  59                         p.FromDictInterface(i.(map[string]interface{}))
  60                         *me = append(*me, p)
  61                 }
  62                 return
  63         default:
  64                 vars.Add("http responses with unhandled peers type", 1)
  65                 err = fmt.Errorf("unsupported type: %T", _v)
  66                 return
  67         }
  68 }
  69
  70 func setAnnounceParams(_url *url.URL, ar *AnnounceRequest, opts Announce) {
  71         q := _url.Query()
  72
  73         q.Set("info_hash", string(ar.InfoHash[:]))
  74         q.Set("peer_id", string(ar.PeerId[:]))
  75         // AFAICT, port is mandatory, and there's no implied port key.
  76         q.Set("port", fmt.Sprintf("%d", ar.Port))
  77         q.Set("uploaded", strconv.FormatInt(ar.Uploaded, 10))
  78         q.Set("downloaded", strconv.FormatInt(ar.Downloaded, 10))
  79
  80         // The AWS S3 tracker returns "400 Bad Request: left(-1) was not in the valid range 0 -
  81         // 9223372036854775807" if left is out of range, or "500 Internal Server Error: Internal Server
  82         // Error" if omitted entirely.
  83         left := ar.Left
  84         if left < 0 {
  85                 left = math.MaxInt64
  86         }
  87         q.Set("left", strconv.FormatInt(left, 10))
  88
  89         if ar.Event != None {
  90                 q.Set("event", ar.Event.String())
  91         }
  92         // http://stackoverflow.com/questions/17418004/why-does-tracker-server-not-understand-my-request-bittorrent-protocol
  93         q.Set("compact", "1")
  94         // According to https://wiki.vuze.com/w/Message_Stream_Encryption. TODO:
  95         // Take EncryptionPolicy or something like it as a parameter.
  96         q.Set("supportcrypto", "1")
  97         if opts.ClientIp4.IP != nil {
  98                 q.Set("ipv4", opts.ClientIp4.String())
  99         }
 100         if opts.ClientIp6.IP != nil {
 101                 q.Set("ipv6", opts.ClientIp6.String())
 102         }
 103         _url.RawQuery = q.Encode()
 104 }
 105
 106 func announceHTTP(opt Announce, _url *url.URL) (ret AnnounceResponse, err error) {
 107         _url = httptoo.CopyURL(_url)
 108         setAnnounceParams(_url, &opt.Request, opt)
 109         req, err := http.NewRequest("GET", _url.String(), nil)
 110         req.Header.Set("User-Agent", opt.UserAgent)
 111         req.Host = opt.HostHeader
 112         if opt.Context != nil {
 113                 req = req.WithContext(opt.Context)
 114         }
 115         resp, err := (&http.Client{
 116                 Timeout: time.Second * 15,
 117                 Transport: &http.Transport{
 118                         Dial: (&net.Dialer{
 119                                 Timeout: 15 * time.Second,
 120                         }).Dial,
 121                         Proxy:               opt.HTTPProxy,
 122                         TLSHandshakeTimeout: 15 * time.Second,
 123                         TLSClientConfig: &tls.Config{
 124                                 InsecureSkipVerify: true,
 125                                 ServerName:         opt.ServerName,
 126                         },
 127                         DisableKeepAlives: true,
 128                 },
 129         }).Do(req)
 130         if err != nil {
 131                 return
 132         }
 133         defer resp.Body.Close()
 134         var buf bytes.Buffer
 135         io.Copy(&buf, resp.Body)
 136         if resp.StatusCode != 200 {
 137                 err = fmt.Errorf("response from tracker: %s: %s", resp.Status, buf.String())
 138                 return
 139         }
 140         var trackerResponse HttpResponse
 141         err = bencode.Unmarshal(buf.Bytes(), &trackerResponse)
 142         if _, ok := err.(bencode.ErrUnusedTrailingBytes); ok {
 143                 err = nil
 144         } else if err != nil {
 145                 err = fmt.Errorf("error decoding %q: %s", buf.Bytes(), err)
 146                 return
 147         }
 148         if trackerResponse.FailureReason != "" {
 149                 err = fmt.Errorf("tracker gave failure reason: %q", trackerResponse.FailureReason)
 150                 return
 151         }
 152         vars.Add("successful http announces", 1)
 153         ret.Interval = trackerResponse.Interval
 154         ret.Leechers = trackerResponse.Incomplete
 155         ret.Seeders = trackerResponse.Complete
 156         if len(trackerResponse.Peers) != 0 {
 157                 vars.Add("http responses with nonempty peers key", 1)
 158         }
 159         ret.Peers = trackerResponse.Peers
 160         if len(trackerResponse.Peers6) != 0 {
 161                 vars.Add("http responses with nonempty peers6 key", 1)
 162         }
 163         for _, na := range trackerResponse.Peers6 {
 164                 ret.Peers = append(ret.Peers, Peer{
 165                         IP:   na.IP,
 166                         Port: na.Port,
 167                 })
 168         }
 169         return
 170 }