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mirror of synced 2025-02-24 14:48:27 +00:00

126 lines
3.3 KiB
Go

package httpTrackerServer
import (
"fmt"
"net"
"net/http"
"net/netip"
"net/url"
"strconv"
"github.com/anacrolix/dht/v2/krpc"
"github.com/anacrolix/generics"
"github.com/anacrolix/log"
trackerServer "github.com/anacrolix/torrent/tracker/server"
"github.com/anacrolix/torrent/bencode"
"github.com/anacrolix/torrent/tracker"
httpTracker "github.com/anacrolix/torrent/tracker/http"
)
type Handler struct {
Announce *trackerServer.AnnounceHandler
// Called to derive an announcer's IP if non-nil. If not specified, the Request.RemoteAddr is
// used. Necessary for instances running behind reverse proxies for example.
RequestHost func(r *http.Request) (netip.Addr, error)
}
func unmarshalQueryKeyToArray(w http.ResponseWriter, key string, query url.Values) (ret [20]byte, ok bool) {
str := query.Get(key)
if len(str) != len(ret) {
http.Error(w, fmt.Sprintf("%v has wrong length", key), http.StatusBadRequest)
return
}
copy(ret[:], str)
ok = true
return
}
// Returns false if there was an error and it was served.
func (me Handler) requestHostAddr(r *http.Request) (_ netip.Addr, err error) {
if me.RequestHost != nil {
return me.RequestHost(r)
}
host, _, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
return
}
return netip.ParseAddr(host)
}
var requestHeadersLogger = log.Default.WithNames("request", "headers")
func (me Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
vs := r.URL.Query()
var event tracker.AnnounceEvent
err := event.UnmarshalText([]byte(vs.Get("event")))
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
infoHash, ok := unmarshalQueryKeyToArray(w, "info_hash", vs)
if !ok {
return
}
peerId, ok := unmarshalQueryKeyToArray(w, "peer_id", vs)
if !ok {
return
}
requestHeadersLogger.Levelf(log.Debug, "request RemoteAddr=%q, header=%q", r.RemoteAddr, r.Header)
addr, err := me.requestHostAddr(r)
if err != nil {
log.Printf("error getting requester IP: %v", err)
http.Error(w, "error determining your IP", http.StatusBadGateway)
return
}
portU64, _ := strconv.ParseUint(vs.Get("port"), 0, 16)
addrPort := netip.AddrPortFrom(addr, uint16(portU64))
left, err := strconv.ParseInt(vs.Get("left"), 0, 64)
if err != nil {
left = -1
}
res := me.Announce.Serve(
r.Context(),
tracker.AnnounceRequest{
InfoHash: infoHash,
PeerId: peerId,
Event: event,
Port: addrPort.Port(),
NumWant: -1,
Left: left,
},
addrPort,
trackerServer.GetPeersOpts{
MaxCount: generics.Some[uint](200),
},
)
err = res.Err
if err != nil {
log.Printf("error serving announce: %v", err)
http.Error(w, "error handling announce", http.StatusInternalServerError)
return
}
var resp httpTracker.HttpResponse
resp.Incomplete = res.Leechers.Value
resp.Complete = res.Seeders.Value
resp.Interval = res.Interval.UnwrapOr(5 * 60)
resp.Peers.Compact = true
for _, peer := range res.Peers {
if peer.Addr().Is4() {
resp.Peers.List = append(resp.Peers.List, tracker.Peer{
IP: peer.Addr().AsSlice(),
Port: int(peer.Port()),
})
} else if peer.Addr().Is6() {
resp.Peers6 = append(resp.Peers6, krpc.NodeAddr{
IP: peer.Addr().AsSlice(),
Port: int(peer.Port()),
})
}
}
err = bencode.NewEncoder(w).Encode(resp)
if err != nil {
log.Printf("error encoding and writing response body: %v", err)
}
}