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
  14         "github.com/anacrolix/dht/v2/krpc"
  15         "github.com/anacrolix/missinggo/httptoo"
  16
  17         "github.com/anacrolix/torrent/bencode"
  18 )
  19
  20 type HttpResponse struct {
  21         FailureReason string `bencode:"failure reason"`
  22         Interval      int32  `bencode:"interval"`
  23         TrackerId     string `bencode:"tracker id"`
  24         Complete      int32  `bencode:"complete"`
  25         Incomplete    int32  `bencode:"incomplete"`
  26         Peers         Peers  `bencode:"peers"`
  27         // BEP 7
  28         Peers6 krpc.CompactIPv6NodeAddrs `bencode:"peers6"`
  29 }
  30
  31 type Peers []Peer
  32
  33 func (me *Peers) UnmarshalBencode(b []byte) (err error) {
  34         var _v interface{}
  35         err = bencode.Unmarshal(b, &_v)
  36         if err != nil {
  37                 return
  38         }
  39         switch v := _v.(type) {
  40         case string:
  41                 vars.Add("http responses with string peers", 1)
  42                 var cnas krpc.CompactIPv4NodeAddrs
  43                 err = cnas.UnmarshalBinary([]byte(v))
  44                 if err != nil {
  45                         return
  46                 }
  47                 for _, cp := range cnas {
  48                         *me = append(*me, Peer{
  49                                 IP:   cp.IP[:],
  50                                 Port: int(cp.Port),
  51                         })
  52                 }
  53                 return
  54         case []interface{}:
  55                 vars.Add("http responses with list peers", 1)
  56                 for _, i := range v {
  57                         var p Peer
  58                         p.FromDictInterface(i.(map[string]interface{}))
  59                         *me = append(*me, p)
  60                 }
  61                 return
  62         default:
  63                 vars.Add("http responses with unhandled peers type", 1)
  64                 err = fmt.Errorf("unsupported type: %T", _v)
  65                 return
  66         }
  67 }
  68
  69 func setAnnounceParams(_url *url.URL, ar *AnnounceRequest, opts Announce) {
  70         q := _url.Query()
  71
  72         q.Set("key", strconv.FormatInt(int64(ar.Key), 10))
  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         doIp := func(versionKey string, ip net.IP) {
  98                 if ip == nil {
  99                         return
 100                 }
 101                 ipString := ip.String()
 102                 q.Set(versionKey, ipString)
 103                 // Let's try listing them. BEP 3 mentions having an "ip" param, and BEP 7 says we can list
 104                 // addresses for other address-families, although it's not encouraged.
 105                 q.Add("ip", ipString)
 106         }
 107         doIp("ipv4", opts.ClientIp4.IP)
 108         doIp("ipv6", opts.ClientIp6.IP)
 109         _url.RawQuery = q.Encode()
 110 }
 111
 112 func announceHTTP(opt Announce, _url *url.URL) (ret AnnounceResponse, err error) {
 113         _url = httptoo.CopyURL(_url)
 114         setAnnounceParams(_url, &opt.Request, opt)
 115         req, err := http.NewRequest("GET", _url.String(), nil)
 116         req.Header.Set("User-Agent", opt.UserAgent)
 117         req.Host = opt.HostHeader
 118         if opt.Context != nil {
 119                 req = req.WithContext(opt.Context)
 120         }
 121         resp, err := (&http.Client{
 122                 //Timeout: time.Second * 15,
 123                 Transport: &http.Transport{
 124                         //Dial: (&net.Dialer{
 125                         //      Timeout: 15 * time.Second,
 126                         //}).Dial,
 127                         Proxy: opt.HTTPProxy,
 128                         //TLSHandshakeTimeout: 15 * time.Second,
 129                         TLSClientConfig: &tls.Config{
 130                                 InsecureSkipVerify: true,
 131                                 ServerName:         opt.ServerName,
 132                         },
 133                         // This is for S3 trackers that hold connections open.
 134                         DisableKeepAlives: true,
 135                 },
 136         }).Do(req)
 137         if err != nil {
 138                 return
 139         }
 140         defer resp.Body.Close()
 141         var buf bytes.Buffer
 142         io.Copy(&buf, resp.Body)
 143         if resp.StatusCode != 200 {
 144                 err = fmt.Errorf("response from tracker: %s: %s", resp.Status, buf.String())
 145                 return
 146         }
 147         var trackerResponse HttpResponse
 148         err = bencode.Unmarshal(buf.Bytes(), &trackerResponse)
 149         if _, ok := err.(bencode.ErrUnusedTrailingBytes); ok {
 150                 err = nil
 151         } else if err != nil {
 152                 err = fmt.Errorf("error decoding %q: %s", buf.Bytes(), err)
 153                 return
 154         }
 155         if trackerResponse.FailureReason != "" {
 156                 err = fmt.Errorf("tracker gave failure reason: %q", trackerResponse.FailureReason)
 157                 return
 158         }
 159         vars.Add("successful http announces", 1)
 160         ret.Interval = trackerResponse.Interval
 161         ret.Leechers = trackerResponse.Incomplete
 162         ret.Seeders = trackerResponse.Complete
 163         if len(trackerResponse.Peers) != 0 {
 164                 vars.Add("http responses with nonempty peers key", 1)
 165         }
 166         ret.Peers = trackerResponse.Peers
 167         if len(trackerResponse.Peers6) != 0 {
 168                 vars.Add("http responses with nonempty peers6 key", 1)
 169         }
 170         for _, na := range trackerResponse.Peers6 {
 171                 ret.Peers = append(ret.Peers, Peer{
 172                         IP:   na.IP,
 173                         Port: na.Port,
 174                 })
 175         }
 176         return
 177 }