FedP2P/client.go

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/*
Package torrent implements a torrent client.
Simple example:
c := &Client{}
c.Start()
defer c.Stop()
if err := c.AddTorrent(externalMetaInfoPackageSux); err != nil {
return fmt.Errors("error adding torrent: %s", err)
}
c.WaitAll()
log.Print("erhmahgerd, torrent downloaded")
*/
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package torrent
import (
"bufio"
"bytes"
"container/heap"
"crypto/rand"
"crypto/sha1"
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"errors"
"expvar"
"fmt"
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"io"
"log"
"math/big"
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mathRand "math/rand"
"net"
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"os"
"path/filepath"
"sort"
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"strings"
"syscall"
"time"
filePkg "bitbucket.org/anacrolix/go.torrent/data/file"
"bitbucket.org/anacrolix/go.torrent/dht"
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"bitbucket.org/anacrolix/go.torrent/internal/pieceordering"
"bitbucket.org/anacrolix/go.torrent/iplist"
pp "bitbucket.org/anacrolix/go.torrent/peer_protocol"
"bitbucket.org/anacrolix/go.torrent/tracker"
_ "bitbucket.org/anacrolix/go.torrent/tracker/udp"
. "bitbucket.org/anacrolix/go.torrent/util"
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"bitbucket.org/anacrolix/sync"
"bitbucket.org/anacrolix/utp"
"github.com/anacrolix/libtorgo/bencode"
"github.com/anacrolix/libtorgo/metainfo"
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)
var (
unusedDownloadedChunksCount = expvar.NewInt("unusedDownloadedChunksCount")
chunksDownloadedCount = expvar.NewInt("chunksDownloadedCount")
peersFoundByDHT = expvar.NewInt("peersFoundByDHT")
peersFoundByPEX = expvar.NewInt("peersFoundByPEX")
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uploadChunksPosted = expvar.NewInt("uploadChunksPosted")
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unexpectedCancels = expvar.NewInt("unexpectedCancels")
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postedCancels = expvar.NewInt("postedCancels")
duplicateConnsAvoided = expvar.NewInt("duplicateConnsAvoided")
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failedPieceHashes = expvar.NewInt("failedPieceHashes")
unsuccessfulDials = expvar.NewInt("unsuccessfulDials")
successfulDials = expvar.NewInt("successfulDials")
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acceptedConns = expvar.NewInt("acceptedConns")
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inboundConnsBlocked = expvar.NewInt("inboundConnsBlocked")
)
const (
// Justification for set bits follows.
//
// Extension protocol: http://www.bittorrent.org/beps/bep_0010.html
// DHT: http://www.bittorrent.org/beps/bep_0005.html
extensionBytes = "\x00\x00\x00\x00\x00\x10\x00\x01"
socketsPerTorrent = 40
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torrentPeersHighWater = 200
torrentPeersLowWater = 50
// Limit how long handshake can take. This is to reduce the lingering
// impact of a few bad apples. 4s loses 1% of successful handshakes that
// are obtained with 60s timeout, and 5% of unsuccessful handshakes.
handshakeTimeout = 4 * time.Second
pruneInterval = 10 * time.Second
)
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// Currently doesn't really queue, but should in the future.
func (cl *Client) queuePieceCheck(t *torrent, pieceIndex pp.Integer) {
piece := t.Pieces[pieceIndex]
if piece.QueuedForHash {
return
}
piece.QueuedForHash = true
go cl.verifyPiece(t, pieceIndex)
}
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// Queue a piece check if one isn't already queued, and the piece has never
// been checked before.
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func (cl *Client) queueFirstHash(t *torrent, piece int) {
p := t.Pieces[piece]
if p.EverHashed || p.Hashing || p.QueuedForHash {
return
}
cl.queuePieceCheck(t, pp.Integer(piece))
}
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type Client struct {
noUpload bool
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dataDir string
halfOpenLimit int
peerID [20]byte
listeners []net.Listener
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utpSock *utp.Socket
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disableTrackers bool
downloadStrategy DownloadStrategy
dHT *dht.Server
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disableUTP bool
disableTCP bool
ipBlockList *iplist.IPList
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bannedTorrents map[InfoHash]struct{}
_configDir string
config Config
pruneTimer *time.Timer
torrentDataOpener TorrentDataOpener
mu sync.RWMutex
event sync.Cond
quit chan struct{}
handshaking int
torrents map[InfoHash]*torrent
}
func (me *Client) IPBlockList() *iplist.IPList {
me.mu.Lock()
defer me.mu.Unlock()
return me.ipBlockList
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}
func (me *Client) SetIPBlockList(list *iplist.IPList) {
me.mu.Lock()
defer me.mu.Unlock()
me.ipBlockList = list
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if me.dHT != nil {
me.dHT.SetIPBlockList(list)
}
}
func (me *Client) PeerID() string {
return string(me.peerID[:])
}
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func (me *Client) ListenAddr() (addr net.Addr) {
for _, l := range me.listeners {
if addr != nil && l.Addr().String() != addr.String() {
panic("listeners exist on different addresses")
}
addr = l.Addr()
}
return
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}
type hashSorter struct {
Hashes []InfoHash
}
func (me hashSorter) Len() int {
return len(me.Hashes)
}
func (me hashSorter) Less(a, b int) bool {
return (&big.Int{}).SetBytes(me.Hashes[a][:]).Cmp((&big.Int{}).SetBytes(me.Hashes[b][:])) < 0
}
func (me hashSorter) Swap(a, b int) {
me.Hashes[a], me.Hashes[b] = me.Hashes[b], me.Hashes[a]
}
func (cl *Client) sortedTorrents() (ret []*torrent) {
var hs hashSorter
for ih := range cl.torrents {
hs.Hashes = append(hs.Hashes, ih)
}
sort.Sort(hs)
for _, ih := range hs.Hashes {
ret = append(ret, cl.torrent(ih))
}
return
}
func (cl *Client) WriteStatus(_w io.Writer) {
cl.mu.RLock()
defer cl.mu.RUnlock()
w := bufio.NewWriter(_w)
defer w.Flush()
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if addr := cl.ListenAddr(); addr != nil {
fmt.Fprintf(w, "Listening on %s\n", cl.ListenAddr())
} else {
fmt.Println("Not listening!")
}
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fmt.Fprintf(w, "Peer ID: %q\n", cl.peerID)
fmt.Fprintf(w, "Handshaking: %d\n", cl.handshaking)
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if cl.dHT != nil {
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dhtStats := cl.dHT.Stats()
fmt.Fprintf(w, "DHT nodes: %d (%d good)\n", dhtStats.NumNodes, dhtStats.NumGoodNodes)
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fmt.Fprintf(w, "DHT Server ID: %x\n", cl.dHT.IDString())
fmt.Fprintf(w, "DHT port: %d\n", addrPort(cl.dHT.LocalAddr()))
fmt.Fprintf(w, "DHT announces: %d\n", cl.dHT.NumConfirmedAnnounces)
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fmt.Fprintf(w, "Outstanding transactions: %d\n", dhtStats.NumOutstandingTransactions)
}
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cl.downloadStrategy.WriteStatus(w)
fmt.Fprintln(w)
for _, t := range cl.sortedTorrents() {
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if t.Name() == "" {
fmt.Fprint(w, "<unknown name>")
} else {
fmt.Fprint(w, t.Name())
}
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fmt.Fprint(w, "\n")
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if t.haveInfo() {
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fmt.Fprintf(w, "%f%% of %d bytes", 100*(1-float32(t.BytesLeft())/float32(t.Length())), t.Length())
} else {
w.WriteString("<missing metainfo>")
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}
fmt.Fprint(w, "\n")
t.WriteStatus(w)
fmt.Fprintln(w)
}
}
// Read torrent data at the given offset. Will block until it is available.
func (cl *Client) torrentReadAt(t *torrent, off int64, p []byte) (n int, err error) {
cl.mu.Lock()
defer cl.mu.Unlock()
index := int(off / int64(t.UsualPieceSize()))
// Reading outside the bounds of a file is an error.
if index < 0 {
err = os.ErrInvalid
return
}
if int(index) >= len(t.Pieces) {
err = io.EOF
return
}
piece := t.Pieces[index]
pieceOff := pp.Integer(off % int64(t.UsualPieceSize()))
pieceLeft := int(t.PieceLength(pp.Integer(index)) - pieceOff)
if pieceLeft <= 0 {
err = io.EOF
return
}
cl.readRaisePiecePriorities(t, off, int64(len(p)))
if len(p) > pieceLeft {
p = p[:pieceLeft]
}
if len(p) == 0 {
panic(len(p))
}
for !piece.Complete() && !t.isClosed() {
piece.Event.Wait()
}
return t.data.ReadAt(p, off)
}
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func (cl *Client) readRaisePiecePriorities(t *torrent, off, _len int64) {
index := int(off / int64(t.UsualPieceSize()))
cl.raisePiecePriority(t, index, piecePriorityNow)
index++
if index >= t.numPieces() {
return
}
cl.raisePiecePriority(t, index, piecePriorityNext)
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for i := 0; i < 3; i++ {
index++
if index >= t.numPieces() {
break
}
cl.raisePiecePriority(t, index, piecePriorityReadahead)
}
}
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func (cl *Client) configDir() string {
if cl._configDir == "" {
return filepath.Join(os.Getenv("HOME"), ".config/torrent")
}
return cl._configDir
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}
func (cl *Client) ConfigDir() string {
return cl.configDir()
}
func (t *torrent) connPendPiece(c *connection, piece int) {
c.pendPiece(piece, t.Pieces[piece].Priority)
}
func (cl *Client) raisePiecePriority(t *torrent, piece int, priority piecePriority) {
if t.Pieces[piece].Priority < priority {
cl.prioritizePiece(t, piece, priority)
}
}
func (cl *Client) prioritizePiece(t *torrent, piece int, priority piecePriority) {
if t.havePiece(piece) {
return
}
cl.queueFirstHash(t, piece)
t.Pieces[piece].Priority = priority
if t.wantPiece(piece) {
for _, c := range t.Conns {
if c.PeerHasPiece(pp.Integer(piece)) {
t.connPendPiece(c, piece)
cl.replenishConnRequests(t, c)
}
}
}
}
func (cl *Client) setEnvBlocklist() (err error) {
filename := os.Getenv("TORRENT_BLOCKLIST_FILE")
defaultBlocklist := filename == ""
if defaultBlocklist {
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filename = filepath.Join(cl.configDir(), "blocklist")
}
f, err := os.Open(filename)
if err != nil {
if defaultBlocklist {
err = nil
}
return
}
defer f.Close()
var ranges []iplist.Range
uniqStrs := make(map[string]string)
scanner := bufio.NewScanner(f)
for scanner.Scan() {
r, ok, lineErr := iplist.ParseBlocklistP2PLine(scanner.Bytes())
if lineErr != nil {
err = fmt.Errorf("error reading torrent blocklist line: %s", lineErr)
return
}
if !ok {
continue
}
if s, ok := uniqStrs[r.Description]; ok {
r.Description = s
} else {
uniqStrs[r.Description] = r.Description
}
ranges = append(ranges, r)
}
err = scanner.Err()
if err != nil {
err = fmt.Errorf("error reading torrent blocklist: %s", err)
return
}
cl.ipBlockList = iplist.New(ranges)
return
}
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func (cl *Client) initBannedTorrents() error {
f, err := os.Open(filepath.Join(cl.configDir(), "banned_infohashes"))
if err != nil {
if os.IsNotExist(err) {
return nil
}
return fmt.Errorf("error opening banned infohashes file: %s", err)
}
defer f.Close()
scanner := bufio.NewScanner(f)
cl.bannedTorrents = make(map[InfoHash]struct{})
for scanner.Scan() {
var ihs string
n, err := fmt.Sscanf(scanner.Text(), "%x", &ihs)
if err != nil {
return fmt.Errorf("error reading infohash: %s", err)
}
if n != 1 {
continue
}
if len(ihs) != 20 {
return errors.New("bad infohash")
}
var ih InfoHash
CopyExact(&ih, ihs)
cl.bannedTorrents[ih] = struct{}{}
}
if err := scanner.Err(); err != nil {
return fmt.Errorf("error scanning file: %s", err)
}
return nil
}
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func NewClient(cfg *Config) (cl *Client, err error) {
if cfg == nil {
cfg = &Config{}
}
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cl = &Client{
noUpload: cfg.NoUpload,
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disableTrackers: cfg.DisableTrackers,
downloadStrategy: cfg.DownloadStrategy,
halfOpenLimit: socketsPerTorrent,
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dataDir: cfg.DataDir,
disableUTP: cfg.DisableUTP,
disableTCP: cfg.DisableTCP,
_configDir: cfg.ConfigDir,
config: *cfg,
torrentDataOpener: func(md *metainfo.Info) (TorrentData, error) {
return filePkg.TorrentData(md, cfg.DataDir), nil
},
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quit: make(chan struct{}),
torrents: make(map[InfoHash]*torrent),
}
cl.event.L = &cl.mu
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if cfg.TorrentDataOpener != nil {
cl.torrentDataOpener = cfg.TorrentDataOpener
}
if !cfg.NoDefaultBlocklist {
err = cl.setEnvBlocklist()
if err != nil {
return
}
}
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if err = cl.initBannedTorrents(); err != nil {
err = fmt.Errorf("error initing banned torrents: %s", err)
return
}
if cfg.PeerID != "" {
CopyExact(&cl.peerID, cfg.PeerID)
} else {
o := copy(cl.peerID[:], BEP20)
_, err = rand.Read(cl.peerID[o:])
if err != nil {
panic("error generating peer id")
}
}
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if cl.downloadStrategy == nil {
cl.downloadStrategy = &DefaultDownloadStrategy{}
}
// Returns the laddr string to listen on for the next Listen call.
listenAddr := func() string {
if addr := cl.ListenAddr(); addr != nil {
return addr.String()
}
if cfg.ListenAddr == "" {
return ":50007"
}
return cfg.ListenAddr
}
if !cl.disableTCP {
var l net.Listener
l, err = net.Listen("tcp", listenAddr())
if err != nil {
return
}
cl.listeners = append(cl.listeners, l)
go cl.acceptConnections(l, false)
}
if !cl.disableUTP {
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cl.utpSock, err = utp.NewSocket(listenAddr())
if err != nil {
return
}
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cl.listeners = append(cl.listeners, cl.utpSock)
go cl.acceptConnections(cl.utpSock, true)
}
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if !cfg.NoDHT {
dhtCfg := cfg.DHTConfig
if dhtCfg == nil {
dhtCfg = &dht.ServerConfig{}
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}
if dhtCfg.Addr == "" {
dhtCfg.Addr = listenAddr()
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}
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if dhtCfg.Conn == nil && cl.utpSock != nil {
dhtCfg.Conn = cl.utpSock.PacketConn()
}
cl.dHT, err = dht.NewServer(dhtCfg)
if cl.ipBlockList != nil {
cl.dHT.SetIPBlockList(cl.ipBlockList)
}
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if err != nil {
return
}
}
return
}
func (cl *Client) stopped() bool {
select {
case <-cl.quit:
return true
default:
return false
}
}
// Stops the client. All connections to peers are closed and all activity will
// come to a halt.
func (me *Client) Stop() {
me.mu.Lock()
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defer me.mu.Unlock()
close(me.quit)
for _, l := range me.listeners {
l.Close()
}
me.event.Broadcast()
for _, t := range me.torrents {
t.close()
}
}
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var ipv6BlockRange = iplist.Range{Description: "non-IPv4 address"}
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func (cl *Client) ipBlockRange(ip net.IP) (r *iplist.Range) {
if cl.ipBlockList == nil {
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return
}
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ip = ip.To4()
if ip == nil {
log.Printf("saw non-IPv4 address")
r = &ipv6BlockRange
return
}
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r = cl.ipBlockList.Lookup(ip)
return
}
func (cl *Client) acceptConnections(l net.Listener, utp bool) {
for {
// We accept all connections immediately, because we don't know what
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// torrent they're for.
conn, err := l.Accept()
select {
case <-cl.quit:
if conn != nil {
conn.Close()
}
return
default:
}
if err != nil {
log.Print(err)
return
}
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acceptedConns.Add(1)
cl.mu.RLock()
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blockRange := cl.ipBlockRange(AddrIP(conn.RemoteAddr()))
cl.mu.RUnlock()
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if blockRange != nil {
inboundConnsBlocked.Add(1)
log.Printf("inbound connection from %s blocked by %s", conn.RemoteAddr(), blockRange)
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conn.Close()
continue
}
go func() {
if err := cl.runConnection(conn, nil, peerSourceIncoming, utp); err != nil {
log.Print(err)
}
}()
}
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}
func (me *Client) torrent(ih InfoHash) *torrent {
for _, t := range me.torrents {
if t.InfoHash == ih {
return t
}
}
return nil
}
type dialResult struct {
net.Conn
UTP bool
}
func doDial(dial func(addr string) (net.Conn, error), ch chan dialResult, utp bool, addr string) {
conn, err := dial(addr)
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if err != nil {
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if conn != nil {
conn.Close()
}
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conn = nil // Pedantic
}
ch <- dialResult{conn, utp}
if err == nil {
successfulDials.Add(1)
return
}
unsuccessfulDials.Add(1)
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
return
}
if netOpErr, ok := err.(*net.OpError); ok {
switch netOpErr.Err {
case syscall.ECONNREFUSED, syscall.EHOSTUNREACH:
return
}
}
if err != nil {
log.Printf("error dialing %s: %s", addr, err)
return
}
}
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func reducedDialTimeout(max time.Duration, halfOpenLimit int, pendingPeers int) (ret time.Duration) {
ret = max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
if ret < minDialTimeout {
ret = minDialTimeout
}
return
}
// Start the process of connecting to the given peer for the given torrent if
// appropriate.
func (me *Client) initiateConn(peer Peer, t *torrent) {
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if peer.Id == me.peerID {
return
}
addr := net.JoinHostPort(peer.IP.String(), fmt.Sprintf("%d", peer.Port))
if t.addrActive(addr) {
duplicateConnsAvoided.Add(1)
return
}
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if r := me.ipBlockRange(peer.IP); r != nil {
log.Printf("outbound connect to %s blocked by IP blocklist rule %s", peer.IP, r)
return
}
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dialTimeout := reducedDialTimeout(nominalDialTimeout, me.halfOpenLimit, len(t.Peers))
t.HalfOpen[addr] = struct{}{}
go func() {
// Binding to the listen address and dialing via net.Dialer gives
// "address in use" error. It seems it's not possible to dial out from
// this address so that peers associate our local address with our
// listen address.
// Initiate connections via TCP and UTP simultaneously. Use the first
// one that succeeds.
left := 0
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if !me.disableUTP {
left++
}
if !me.disableTCP {
left++
}
resCh := make(chan dialResult, left)
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if !me.disableUTP {
go doDial(func(addr string) (net.Conn, error) {
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return me.utpSock.DialTimeout(addr, dialTimeout)
}, resCh, true, addr)
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}
if !me.disableTCP {
go doDial(func(addr string) (net.Conn, error) {
// time.Sleep(time.Second) // Give uTP a bit of a head start.
return net.DialTimeout("tcp", addr, dialTimeout)
}, resCh, false, addr)
}
var res dialResult
for ; left > 0 && res.Conn == nil; left-- {
res = <-resCh
}
// Whether or not the connection attempt succeeds, the half open
// counter should be decremented, and new connection attempts made.
go func() {
me.mu.Lock()
defer me.mu.Unlock()
if _, ok := t.HalfOpen[addr]; !ok {
panic("invariant broken")
}
delete(t.HalfOpen, addr)
me.openNewConns(t)
}()
if res.Conn == nil {
return
}
if left > 0 {
go func() {
for ; left > 0; left-- {
conn := (<-resCh).Conn
if conn != nil {
conn.Close()
}
}
}()
}
// log.Printf("connected to %s", conn.RemoteAddr())
err := me.runConnection(res.Conn, t, peer.Source, res.UTP)
if err != nil {
log.Print(err)
}
}()
}
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// The port number for incoming peer connections. 0 if the client isn't
// listening.
func (cl *Client) incomingPeerPort() int {
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listenAddr := cl.ListenAddr()
if listenAddr == nil {
return 0
}
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return addrPort(listenAddr)
}
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// Convert a net.Addr to its compact IP representation. Either 4 or 16 bytes
// per "yourip" field of http://www.bittorrent.org/beps/bep_0010.html.
func addrCompactIP(addr net.Addr) (string, error) {
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host, _, err := net.SplitHostPort(addr.String())
if err != nil {
return "", err
}
ip := net.ParseIP(host)
if v4 := ip.To4(); v4 != nil {
if len(v4) != 4 {
panic(v4)
}
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return string(v4), nil
}
2014-11-17 03:16:26 +08:00
return string(ip.To16()), nil
}
func handshakeWriter(w io.WriteCloser, bb <-chan []byte, done chan<- error) {
var err error
for b := range bb {
_, err = w.Write(b)
if err != nil {
w.Close()
break
}
}
done <- err
}
type peerExtensionBytes [8]byte
type peerID [20]byte
type handshakeResult struct {
peerExtensionBytes
peerID
InfoHash
}
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// ih is nil if we expect the peer to declare the InfoHash, such as when the
// peer initiated the connection. Returns ok if the handshake was successful,
// and err if there was an unexpected condition other than the peer simply
// abandoning the handshake.
func handshake(sock io.ReadWriteCloser, ih *InfoHash, peerID [20]byte) (res handshakeResult, ok bool, err error) {
// Bytes to be sent to the peer. Should never block the sender.
postCh := make(chan []byte, 4)
// A single error value sent when the writer completes.
writeDone := make(chan error, 1)
// Performs writes to the socket and ensures posts don't block.
go handshakeWriter(sock, postCh, writeDone)
defer func() {
close(postCh) // Done writing.
if !ok {
return
}
if err != nil {
panic(err)
}
// Wait until writes complete before returning from handshake.
err = <-writeDone
if err != nil {
err = fmt.Errorf("error writing during handshake: %s", err)
}
}()
post := func(bb []byte) {
select {
case postCh <- bb:
default:
panic("mustn't block while posting")
}
2014-03-20 21:14:17 +08:00
}
post([]byte(pp.Protocol))
post([]byte(extensionBytes))
if ih != nil { // We already know what we want.
post(ih[:])
post(peerID[:])
}
var b [68]byte
_, err = io.ReadFull(sock, b[:68])
if err != nil {
err = nil
return
}
if string(b[:20]) != pp.Protocol {
return
}
CopyExact(&res.peerExtensionBytes, b[20:28])
CopyExact(&res.InfoHash, b[28:48])
CopyExact(&res.peerID, b[48:68])
if ih == nil { // We were waiting for the peer to tell us what they wanted.
post(res.InfoHash[:])
post(peerID[:])
}
ok = true
return
}
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// Wraps a raw connection and provides the interface we want for using the
// connection in the message loop.
type peerConn struct {
net.Conn
}
func (pc peerConn) Read(b []byte) (n int, err error) {
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// Keep-alives should be received every 2 mins. Give a bit of gracetime.
err = pc.Conn.SetReadDeadline(time.Now().Add(150 * time.Second))
if err != nil {
2015-01-21 21:42:13 +08:00
err = fmt.Errorf("error setting read deadline: %s", err)
}
n, err = pc.Conn.Read(b)
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// Convert common errors into io.EOF.
if err != nil {
if opError, ok := err.(*net.OpError); ok && opError.Op == "read" && opError.Err == syscall.ECONNRESET {
err = io.EOF
} else if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
if n != 0 {
panic(n)
}
err = io.EOF
}
}
return
}
func (me *Client) runConnection(sock net.Conn, torrent *torrent, discovery peerSource, uTP bool) (err error) {
if tcpConn, ok := sock.(*net.TCPConn); ok {
tcpConn.SetLinger(0)
}
defer sock.Close()
2015-02-21 11:56:17 +08:00
err = sock.SetDeadline(time.Now().Add(handshakeTimeout))
if err != nil {
err = fmt.Errorf("couldn't set handshake deadline: %s", err)
return
}
me.mu.Lock()
me.handshaking++
me.mu.Unlock()
hsRes, ok, err := handshake(sock, func() *InfoHash {
if torrent == nil {
return nil
} else {
return &torrent.InfoHash
}
}(), me.peerID)
me.mu.Lock()
defer me.mu.Unlock()
if me.handshaking == 0 {
panic("handshake count invariant is broken")
}
me.handshaking--
if err != nil {
err = fmt.Errorf("error during handshake: %s", err)
return
}
if !ok {
return
}
if hsRes.peerID == me.peerID {
return
}
torrent = me.torrent(hsRes.InfoHash)
if torrent == nil {
return
}
sock.SetWriteDeadline(time.Time{})
sock = peerConn{sock}
conn := newConnection(sock, hsRes.peerExtensionBytes, hsRes.peerID, uTP)
defer conn.Close()
conn.Discovery = discovery
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if !me.addConnection(torrent, conn) {
return
}
if conn.PeerExtensionBytes[5]&0x10 != 0 {
conn.Post(pp.Message{
Type: pp.Extended,
ExtendedID: pp.HandshakeExtendedID,
ExtendedPayload: func() []byte {
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d := map[string]interface{}{
"m": map[string]int{
"ut_metadata": 1,
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"ut_pex": 2,
},
"v": "go.torrent dev 20140825", // Just the date
// No upload queue is implemented yet.
2014-08-28 08:05:41 +08:00
"reqq": func() int {
if me.noUpload {
// No need to look strange if it costs us nothing.
return 250
} else {
return 1
}
}(),
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}
if torrent.metadataSizeKnown() {
d["metadata_size"] = torrent.metadataSize()
}
if p := me.incomingPeerPort(); p != 0 {
d["p"] = p
}
yourip, err := addrCompactIP(conn.Socket.RemoteAddr())
if err != nil {
log.Printf("error calculating yourip field value in extension handshake: %s", err)
} else {
d["yourip"] = yourip
}
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// log.Printf("sending %v", d)
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b, err := bencode.Marshal(d)
if err != nil {
panic(err)
}
return b
}(),
})
}
if torrent.haveAnyPieces() {
conn.Post(pp.Message{
Type: pp.Bitfield,
Bitfield: torrent.bitfield(),
})
}
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if conn.PeerExtensionBytes[7]&0x01 != 0 && me.dHT != nil {
conn.Post(pp.Message{
Type: pp.Port,
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Port: uint16(AddrPort(me.dHT.LocalAddr())),
2014-08-25 20:12:16 +08:00
})
}
if torrent.haveInfo() {
torrent.initRequestOrdering(conn)
me.replenishConnRequests(torrent, conn)
}
err = me.connectionLoop(torrent, conn)
if err != nil {
err = fmt.Errorf("during Connection loop with peer %q: %s", conn.PeerID, err)
}
me.dropConnection(torrent, conn)
return
}
func (t *torrent) initRequestOrdering(c *connection) {
if c.pieceRequestOrder != nil || c.piecePriorities != nil {
panic("double init of request ordering")
}
c.piecePriorities = mathRand.Perm(t.numPieces())
c.pieceRequestOrder = pieceordering.New()
for i := 0; i < t.numPieces(); i++ {
if !c.PeerHasPiece(pp.Integer(i)) {
continue
}
if !t.wantPiece(i) {
continue
}
t.connPendPiece(c, i)
}
}
func (me *Client) peerGotPiece(t *torrent, c *connection, piece int) {
if t.haveInfo() {
if c.PeerPieces == nil {
c.PeerPieces = make([]bool, t.numPieces())
}
} else {
for piece >= len(c.PeerPieces) {
c.PeerPieces = append(c.PeerPieces, false)
}
}
c.PeerPieces[piece] = true
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if t.wantPiece(piece) {
t.connPendPiece(c, piece)
me.replenishConnRequests(t, c)
}
}
func (me *Client) peerUnchoked(torrent *torrent, conn *connection) {
me.replenishConnRequests(torrent, conn)
}
func (cl *Client) connCancel(t *torrent, cn *connection, r request) (ok bool) {
ok = cn.Cancel(r)
if ok {
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postedCancels.Add(1)
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cl.downloadStrategy.DeleteRequest(t, r)
}
return
}
func (cl *Client) connDeleteRequest(t *torrent, cn *connection, r request) {
if !cn.RequestPending(r) {
return
}
2014-08-21 16:07:06 +08:00
cl.downloadStrategy.DeleteRequest(t, r)
delete(cn.Requests, r)
}
func (cl *Client) requestPendingMetadata(t *torrent, c *connection) {
if t.haveInfo() {
return
}
var pending []int
2014-06-28 17:38:31 +08:00
for index := 0; index < t.MetadataPieceCount(); index++ {
if !t.HaveMetadataPiece(index) {
pending = append(pending, index)
}
}
for _, i := range mathRand.Perm(len(pending)) {
c.Post(pp.Message{
Type: pp.Extended,
ExtendedID: byte(c.PeerExtensionIDs["ut_metadata"]),
ExtendedPayload: func() []byte {
b, err := bencode.Marshal(map[string]int{
"msg_type": 0,
"piece": pending[i],
})
if err != nil {
panic(err)
}
return b
}(),
})
}
}
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func (cl *Client) completedMetadata(t *torrent) {
h := sha1.New()
h.Write(t.MetaData)
var ih InfoHash
CopyExact(&ih, h.Sum(nil))
2014-06-28 17:38:31 +08:00
if ih != t.InfoHash {
log.Print("bad metadata")
t.InvalidateMetadata()
return
}
var info metainfo.Info
err := bencode.Unmarshal(t.MetaData, &info)
if err != nil {
log.Printf("error unmarshalling metadata: %s", err)
t.InvalidateMetadata()
return
}
// TODO(anacrolix): If this fails, I think something harsher should be
// done.
err = cl.setMetaData(t, info, t.MetaData)
if err != nil {
log.Printf("error setting metadata: %s", err)
t.InvalidateMetadata()
return
}
log.Printf("%s: got metadata from peers", t)
2014-06-28 17:38:31 +08:00
}
// Process incoming ut_metadata message.
2014-06-28 17:38:31 +08:00
func (cl *Client) gotMetadataExtensionMsg(payload []byte, t *torrent, c *connection) (err error) {
var d map[string]int
err = bencode.Unmarshal(payload, &d)
if err != nil {
2014-06-30 22:05:28 +08:00
err = fmt.Errorf("error unmarshalling payload: %s: %q", err, payload)
2014-06-28 17:38:31 +08:00
return
}
msgType, ok := d["msg_type"]
if !ok {
err = errors.New("missing msg_type field")
return
}
piece := d["piece"]
switch msgType {
case pp.DataMetadataExtensionMsgType:
if t.haveInfo() {
break
}
begin := len(payload) - metadataPieceSize(d["total_size"], piece)
if begin < 0 || begin >= len(payload) {
log.Printf("got bad metadata piece")
break
}
t.SaveMetadataPiece(piece, payload[begin:])
2014-12-01 17:32:17 +08:00
c.UsefulChunksReceived++
c.lastUsefulChunkReceived = time.Now()
2014-06-28 17:38:31 +08:00
if !t.HaveAllMetadataPieces() {
break
}
cl.completedMetadata(t)
case pp.RequestMetadataExtensionMsgType:
if !t.HaveMetadataPiece(piece) {
c.Post(t.NewMetadataExtensionMessage(c, pp.RejectMetadataExtensionMsgType, d["piece"], nil))
break
}
start := (1 << 14) * piece
c.Post(t.NewMetadataExtensionMessage(c, pp.DataMetadataExtensionMsgType, piece, t.MetaData[start:start+t.metadataPieceSize(piece)]))
2014-06-28 17:38:31 +08:00
case pp.RejectMetadataExtensionMsgType:
default:
err = errors.New("unknown msg_type value")
}
return
}
2014-06-29 17:07:43 +08:00
type peerExchangeMessage struct {
Added CompactPeers `bencode:"added"`
AddedFlags []byte `bencode:"added.f"`
Dropped []tracker.Peer `bencode:"dropped"`
2014-06-29 17:07:43 +08:00
}
2014-11-17 03:16:26 +08:00
// Extracts the port as an integer from an address string.
func addrPort(addr net.Addr) int {
2014-11-17 11:20:49 +08:00
return AddrPort(addr)
2014-11-17 03:16:26 +08:00
}
2014-07-24 11:43:45 +08:00
// Processes incoming bittorrent messages. The client lock is held upon entry
// and exit.
func (me *Client) connectionLoop(t *torrent, c *connection) error {
decoder := pp.Decoder{
2014-11-29 09:42:18 +08:00
R: bufio.NewReader(c.Socket),
MaxLength: 256 * 1024,
}
for {
me.mu.Unlock()
var msg pp.Message
err := decoder.Decode(&msg)
me.mu.Lock()
2014-08-28 07:31:05 +08:00
c.lastMessageReceived = time.Now()
select {
case <-c.closing:
return nil
2014-08-28 07:31:05 +08:00
default:
}
if err != nil {
2014-03-20 21:14:17 +08:00
if me.stopped() || err == io.EOF {
return nil
}
return err
}
if msg.Keepalive {
continue
}
switch msg.Type {
case pp.Choke:
c.PeerChoked = true
for r := range c.Requests {
me.connDeleteRequest(t, c, r)
}
// We can then reset our interest.
me.replenishConnRequests(t, c)
case pp.Unchoke:
c.PeerChoked = false
me.peerUnchoked(t, c)
case pp.Interested:
c.PeerInterested = true
// TODO: This should be done from a dedicated unchoking routine.
if me.noUpload {
break
}
c.Unchoke()
case pp.NotInterested:
c.PeerInterested = false
c.Choke()
case pp.Have:
me.peerGotPiece(t, c, int(msg.Index))
case pp.Request:
if me.noUpload {
break
}
if c.PeerRequests == nil {
c.PeerRequests = make(map[request]struct{}, maxRequests)
}
2014-05-21 15:42:06 +08:00
request := newRequest(msg.Index, msg.Begin, msg.Length)
2015-02-24 22:34:57 +08:00
// TODO: Requests should be satisfied from a dedicated upload
// routine.
// c.PeerRequests[request] = struct{}{}
p := make([]byte, msg.Length)
n, err := t.data.ReadAt(p, int64(t.PieceLength(0))*int64(msg.Index)+int64(msg.Begin))
if err != nil {
2014-06-26 15:30:16 +08:00
return fmt.Errorf("reading t data to serve request %q: %s", request, err)
}
if n != int(msg.Length) {
2014-06-26 15:30:16 +08:00
return fmt.Errorf("bad request: %v", msg)
}
c.Post(pp.Message{
Type: pp.Piece,
Index: msg.Index,
Begin: msg.Begin,
Piece: p,
})
2014-08-22 15:33:17 +08:00
uploadChunksPosted.Add(1)
case pp.Cancel:
2014-04-16 15:33:33 +08:00
req := newRequest(msg.Index, msg.Begin, msg.Length)
if !c.PeerCancel(req) {
2014-08-22 15:47:44 +08:00
unexpectedCancels.Add(1)
2014-04-16 15:33:33 +08:00
}
case pp.Bitfield:
if c.PeerPieces != nil {
err = errors.New("received unexpected bitfield")
break
}
if t.haveInfo() {
if len(msg.Bitfield) < t.numPieces() {
err = errors.New("received invalid bitfield")
break
}
msg.Bitfield = msg.Bitfield[:t.numPieces()]
}
c.PeerPieces = msg.Bitfield
for index, has := range c.PeerPieces {
if has {
me.peerGotPiece(t, c, index)
}
}
case pp.Piece:
err = me.downloadedChunk(t, c, &msg)
case pp.Extended:
switch msg.ExtendedID {
case pp.HandshakeExtendedID:
// TODO: Create a bencode struct for this.
var d map[string]interface{}
err = bencode.Unmarshal(msg.ExtendedPayload, &d)
if err != nil {
err = fmt.Errorf("error decoding extended message payload: %s", err)
break
}
// log.Printf("got handshake from %q: %#v", c.Socket.RemoteAddr().String(), d)
if reqq, ok := d["reqq"]; ok {
if i, ok := reqq.(int64); ok {
c.PeerMaxRequests = int(i)
}
}
if v, ok := d["v"]; ok {
c.PeerClientName = v.(string)
}
m, ok := d["m"]
if !ok {
err = errors.New("handshake missing m item")
break
}
mTyped, ok := m.(map[string]interface{})
if !ok {
err = errors.New("handshake m value is not dict")
break
}
if c.PeerExtensionIDs == nil {
c.PeerExtensionIDs = make(map[string]int64, len(mTyped))
}
for name, v := range mTyped {
id, ok := v.(int64)
if !ok {
log.Printf("bad handshake m item extension ID type: %T", v)
continue
}
if id == 0 {
delete(c.PeerExtensionIDs, name)
} else {
c.PeerExtensionIDs[name] = id
}
}
metadata_sizeUntyped, ok := d["metadata_size"]
if ok {
metadata_size, ok := metadata_sizeUntyped.(int64)
if !ok {
log.Printf("bad metadata_size type: %T", metadata_sizeUntyped)
} else {
2014-06-28 17:38:31 +08:00
t.SetMetadataSize(metadata_size)
}
}
if _, ok := c.PeerExtensionIDs["ut_metadata"]; ok {
me.requestPendingMetadata(t, c)
}
case 1:
2014-06-28 17:38:31 +08:00
err = me.gotMetadataExtensionMsg(msg.ExtendedPayload, t, c)
2014-06-30 22:05:28 +08:00
if err != nil {
err = fmt.Errorf("error handling metadata extension message: %s", err)
}
2014-06-29 17:07:43 +08:00
case 2:
var pexMsg peerExchangeMessage
err := bencode.Unmarshal(msg.ExtendedPayload, &pexMsg)
if err != nil {
err = fmt.Errorf("error unmarshalling PEX message: %s", err)
break
}
go func() {
err := me.AddPeers(t.InfoHash, func() (ret []Peer) {
for _, cp := range pexMsg.Added {
p := Peer{
IP: make([]byte, 4),
Port: int(cp.Port),
Source: peerSourcePEX,
2014-06-29 17:07:43 +08:00
}
if n := copy(p.IP, cp.IP[:]); n != 4 {
panic(n)
}
ret = append(ret, p)
}
return
}())
if err != nil {
log.Printf("error adding PEX peers: %s", err)
return
}
peersFoundByPEX.Add(int64(len(pexMsg.Added)))
2014-06-29 17:07:43 +08:00
}()
2014-06-28 17:38:31 +08:00
default:
2014-07-10 00:59:37 +08:00
err = fmt.Errorf("unexpected extended message ID: %v", msg.ExtendedID)
}
if err != nil {
// That client uses its own extension IDs for outgoing message
// types, which is incorrect.
if bytes.HasPrefix(c.PeerID[:], []byte("-SD0100-")) ||
strings.HasPrefix(string(c.PeerID[:]), "-XL0012-") {
return nil
}
// log.Printf("peer extension map: %#v", c.PeerExtensionIDs)
}
2014-08-25 20:12:16 +08:00
case pp.Port:
if me.dHT == nil {
break
}
2014-11-17 03:16:26 +08:00
pingAddr, err := net.ResolveUDPAddr("", c.Socket.RemoteAddr().String())
if err != nil {
panic(err)
}
if msg.Port != 0 {
pingAddr.Port = int(msg.Port)
}
_, err = me.dHT.Ping(pingAddr)
default:
2014-05-21 15:42:06 +08:00
err = fmt.Errorf("received unknown message type: %#v", msg.Type)
}
if err != nil {
return err
}
}
}
func (me *Client) dropConnection(torrent *torrent, conn *connection) {
for r := range conn.Requests {
me.connDeleteRequest(torrent, conn, r)
}
conn.Close()
for i0, c := range torrent.Conns {
if c != conn {
continue
}
i1 := len(torrent.Conns) - 1
if i0 != i1 {
torrent.Conns[i0] = torrent.Conns[i1]
}
torrent.Conns = torrent.Conns[:i1]
me.openNewConns(torrent)
return
}
2014-05-23 19:02:11 +08:00
panic("connection not found")
}
func (me *Client) addConnection(t *torrent, c *connection) bool {
if me.stopped() {
return false
}
select {
case <-t.ceasingNetworking:
return false
default:
}
if !me.wantConns(t) {
return false
}
2014-03-16 23:30:10 +08:00
for _, c0 := range t.Conns {
if c.PeerID == c0.PeerID {
2014-05-21 15:42:06 +08:00
// Already connected to a client with that ID.
return false
}
}
t.Conns = append(t.Conns, c)
// TODO: This should probably be done by a routine that kills off bad
// connections, and extra connections killed here instead.
if len(t.Conns) > socketsPerTorrent {
wcs := t.worstConnsHeap()
heap.Pop(wcs).(*connection).Close()
}
return true
}
func (t *torrent) needData() bool {
if !t.haveInfo() {
return true
}
for i := range t.Pieces {
if t.wantPiece(i) {
return true
}
}
return false
}
// TODO: I'm sure there's something here to do with seeding.
func (t *torrent) badConn(c *connection) bool {
if time.Now().Sub(c.completedHandshake) < 30*time.Second {
return false
}
if !t.haveInfo() {
return !c.supportsExtension("ut_metadata")
}
return !t.connHasWantedPieces(c)
}
func (t *torrent) numGoodConns() (num int) {
for _, c := range t.Conns {
if !t.badConn(c) {
num++
}
}
return
}
func (me *Client) wantConns(t *torrent) bool {
if !t.needData() && me.noUpload {
return false
}
if t.numGoodConns() >= socketsPerTorrent {
return false
}
return true
}
func (me *Client) openNewConns(t *torrent) {
select {
case <-t.ceasingNetworking:
return
default:
}
for len(t.Peers) != 0 {
if !me.wantConns(t) {
return
}
if len(t.HalfOpen) >= me.halfOpenLimit {
return
}
var (
k peersKey
p Peer
)
for k, p = range t.Peers {
break
}
delete(t.Peers, k)
me.initiateConn(p, t)
}
t.wantPeers.Broadcast()
}
func (me *Client) addPeers(t *torrent, peers []Peer) {
2014-11-30 10:33:17 +08:00
blocked := 0
for i, p := range peers {
if me.ipBlockRange(p.IP) == nil {
continue
}
peers[i] = peers[len(peers)-1]
peers = peers[:len(peers)-1]
i--
blocked++
}
if blocked != 0 {
log.Printf("IP blocklist screened %d peers from being added", blocked)
}
t.AddPeers(peers)
me.openNewConns(t)
}
// Adds peers to the swarm for the torrent corresponding to infoHash.
func (me *Client) AddPeers(infoHash InfoHash, peers []Peer) error {
me.mu.Lock()
defer me.mu.Unlock()
t := me.torrent(infoHash)
if t == nil {
return errors.New("no such torrent")
}
me.addPeers(t, peers)
return nil
}
2014-12-02 06:39:09 +08:00
func (cl *Client) torrentFileCachePath(ih InfoHash) string {
return filepath.Join(cl.configDir(), "torrents", ih.HexString()+".torrent")
}
func (cl *Client) saveTorrentFile(t *torrent) error {
path := cl.torrentFileCachePath(t.InfoHash)
os.MkdirAll(filepath.Dir(path), 0777)
f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
if err != nil {
return fmt.Errorf("error opening file: %s", err)
}
defer f.Close()
e := bencode.NewEncoder(f)
err = e.Encode(t.MetaInfo())
if err != nil {
return fmt.Errorf("error marshalling metainfo: %s", err)
}
mi, err := cl.torrentCacheMetaInfo(t.InfoHash)
if err != nil {
// For example, a script kiddy makes us load too many files, and we're
// able to save the torrent, but not load it again to check it.
return nil
}
if !bytes.Equal(mi.Info.Hash, t.InfoHash[:]) {
log.Fatalf("%x != %x", mi.Info.Hash, t.InfoHash[:])
}
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return nil
}
func (cl *Client) startTorrent(t *torrent) {
if t.Info == nil || t.data == nil {
panic("nope")
}
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// If the client intends to upload, it needs to know what state pieces are
// in.
if !cl.noUpload {
// Queue all pieces for hashing. This is done sequentially to avoid
// spamming goroutines.
for _, p := range t.Pieces {
p.QueuedForHash = true
}
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go func() {
for i := range t.Pieces {
cl.verifyPiece(t, pp.Integer(i))
}
}()
}
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cl.downloadStrategy.TorrentStarted(t)
}
// Storage cannot be changed once it's set.
func (cl *Client) setStorage(t *torrent, td TorrentData) (err error) {
err = t.setStorage(td)
cl.event.Broadcast()
if err != nil {
return
}
cl.startTorrent(t)
return
}
type TorrentDataOpener func(*metainfo.Info) (TorrentData, error)
func (cl *Client) setMetaData(t *torrent, md metainfo.Info, bytes []byte) (err error) {
err = t.setMetadata(md, bytes, &cl.mu)
if err != nil {
return
}
if !cl.config.DisableMetainfoCache {
if err := cl.saveTorrentFile(t); err != nil {
log.Printf("error saving torrent file for %s: %s", t, err)
}
}
if strings.Contains(strings.ToLower(md.Name), "porn") {
cl.dropTorrent(t.InfoHash)
err = errors.New("no porn plx")
return
}
close(t.gotMetainfo)
td, err := cl.torrentDataOpener(&md)
if err != nil {
return
}
err = cl.setStorage(t, td)
return
}
// Prepare a Torrent without any attachment to a Client. That means we can
// initialize fields all fields that don't require the Client without locking
// it.
func newTorrent(ih InfoHash, announceList [][]string, halfOpenLimit int) (t *torrent, err error) {
t = &torrent{
InfoHash: ih,
Peers: make(map[peersKey]Peer),
closing: make(chan struct{}),
ceasingNetworking: make(chan struct{}),
gotMetainfo: make(chan struct{}),
HalfOpen: make(map[string]struct{}),
}
t.wantPeers.L = &t.stateMu
t.GotMetainfo = t.gotMetainfo
t.addTrackers(announceList)
return
}
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func init() {
// For shuffling the tracker tiers.
mathRand.Seed(time.Now().Unix())
}
// The trackers within each tier must be shuffled before use.
// http://stackoverflow.com/a/12267471/149482
// http://www.bittorrent.org/beps/bep_0012.html#order-of-processing
func shuffleTier(tier []tracker.Client) {
for i := range tier {
j := mathRand.Intn(i + 1)
tier[i], tier[j] = tier[j], tier[i]
}
}
func copyTrackers(base [][]tracker.Client) (copy [][]tracker.Client) {
for _, tier := range base {
copy = append(copy, append([]tracker.Client{}, tier...))
}
return
}
func mergeTier(tier []tracker.Client, newURLs []string) []tracker.Client {
nextURL:
for _, url := range newURLs {
for _, tr := range tier {
if tr.URL() == url {
continue nextURL
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}
}
tr, err := tracker.New(url)
if err != nil {
log.Printf("error creating tracker client for %q: %s", url, err)
continue
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}
tier = append(tier, tr)
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}
return tier
}
func (t *torrent) addTrackers(announceList [][]string) {
newTrackers := copyTrackers(t.Trackers)
for tierIndex, tier := range announceList {
if tierIndex < len(newTrackers) {
newTrackers[tierIndex] = mergeTier(newTrackers[tierIndex], tier)
} else {
newTrackers = append(newTrackers, mergeTier(nil, tier))
}
shuffleTier(newTrackers[tierIndex])
}
t.Trackers = newTrackers
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}
type Torrent struct {
cl *Client
*torrent
}
func (t Torrent) NumPieces() int {
return t.numPieces()
}
func (t Torrent) Drop() {
t.cl.dropTorrent(t.InfoHash)
}
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type File struct {
t Torrent
path string
offset int64
length int64
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metainfo.FileInfo
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}
func (f *File) Length() int64 {
return f.length
}
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type FilePieceState struct {
Length int64
State byte
}
func (f *File) Progress() (ret []FilePieceState) {
pieceSize := int64(f.t.UsualPieceSize())
off := f.offset % pieceSize
remaining := f.length
for i := int(f.offset / pieceSize); ; i++ {
if remaining == 0 {
break
}
len1 := pieceSize - off
if len1 > remaining {
len1 = remaining
}
ret = append(ret, FilePieceState{len1, f.t.pieceStatusChar(i)})
off = 0
remaining -= len1
}
return
}
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func (f *File) PrioritizeRegion(off, len int64) {
if off < 0 || off >= f.length {
return
}
if off+len > f.length {
len = f.length - off
}
off += f.offset
f.t.SetRegionPriority(off, len)
}
// Returns handles to the files in the torrent. This requires the metainfo is
// available first.
func (t Torrent) Files() (ret []File) {
select {
case <-t.GotMetainfo:
default:
return
}
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var offset int64
for _, fi := range t.Info.UpvertedFiles() {
ret = append(ret, File{
t,
strings.Join(fi.Path, "/"),
offset,
fi.Length,
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fi,
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})
offset += fi.Length
}
return
}
func (t Torrent) SetRegionPriority(off, len int64) {
t.cl.mu.Lock()
defer t.cl.mu.Unlock()
pieceSize := int64(t.UsualPieceSize())
for i := off / pieceSize; i*pieceSize < off+len; i++ {
t.cl.prioritizePiece(t.torrent, int(i), piecePriorityNormal)
}
}
func (t Torrent) MetainfoFilepath() string {
return filepath.Join(t.cl.ConfigDir(), "torrents", t.InfoHash.HexString()+".torrent")
}
func (t Torrent) AddPeers(pp []Peer) error {
return t.cl.AddPeers(t.torrent.InfoHash, pp)
}
func (t Torrent) DownloadAll() {
t.cl.mu.Lock()
for i := 0; i < t.numPieces(); i++ {
// TODO: Leave higher priorities as they were?
t.cl.prioritizePiece(t.torrent, i, piecePriorityNormal)
}
// Nice to have the first and last pieces soon for various interactive
// purposes.
t.cl.prioritizePiece(t.torrent, 0, piecePriorityReadahead)
t.cl.prioritizePiece(t.torrent, t.numPieces()-1, piecePriorityReadahead)
t.cl.mu.Unlock()
}
func (me Torrent) ReadAt(p []byte, off int64) (n int, err error) {
return me.cl.torrentReadAt(me.torrent, off, p)
}
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// Returns nil metainfo if it isn't in the cache.
func (cl *Client) torrentCacheMetaInfo(ih InfoHash) (mi *metainfo.MetaInfo, err error) {
if cl.config.DisableMetainfoCache {
return
}
f, err := os.Open(cl.torrentFileCachePath(ih))
if err != nil {
if os.IsNotExist(err) {
err = nil
}
return
}
defer f.Close()
dec := bencode.NewDecoder(f)
err = dec.Decode(&mi)
if err != nil {
return
}
if !bytes.Equal(mi.Info.Hash, ih[:]) {
err = fmt.Errorf("cached torrent has wrong infohash: %x != %x", mi.Info.Hash, ih[:])
return
}
return
}
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func (cl *Client) AddMagnet(uri string) (T Torrent, err error) {
m, err := ParseMagnetURI(uri)
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if err != nil {
return
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}
mi, err := cl.torrentCacheMetaInfo(m.InfoHash)
if err != nil {
log.Printf("error getting cached metainfo for %x: %s", m.InfoHash[:], err)
} else if mi != nil {
_, err = cl.AddTorrent(mi)
if err != nil {
return
}
}
cl.mu.Lock()
defer cl.mu.Unlock()
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T, err = cl.addOrMergeTorrent(m.InfoHash, [][]string{m.Trackers})
if err != nil {
return
}
if m.DisplayName != "" {
T.DisplayName = m.DisplayName
}
return
}
// Prunes unused connections. This is required to make space to dial for
// replacements.
func (cl *Client) pruneConnectionsUnlocked(t *torrent) {
select {
case <-t.ceasingNetworking:
return
case <-t.closing:
return
default:
}
cl.mu.Lock()
license := len(t.Conns) - (socketsPerTorrent+1)/2
for _, c := range t.Conns {
if license <= 0 {
break
}
if time.Now().Sub(c.lastUsefulChunkReceived) < time.Minute {
continue
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}
if time.Now().Sub(c.completedHandshake) < time.Minute {
continue
}
c.Close()
license--
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}
cl.mu.Unlock()
t.pruneTimer.Reset(pruneInterval)
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}
func (me *Client) dropTorrent(infoHash InfoHash) (err error) {
t, ok := me.torrents[infoHash]
if !ok {
err = fmt.Errorf("no such torrent")
return
}
err = t.close()
if err != nil {
panic(err)
}
delete(me.torrents, infoHash)
me.downloadStrategy.TorrentStopped(t)
return
}
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func (me *Client) addOrMergeTorrent(ih InfoHash, announceList [][]string) (T Torrent, err error) {
if _, ok := me.bannedTorrents[ih]; ok {
err = errors.New("banned torrent")
return
}
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T.cl = me
var ok bool
T.torrent, ok = me.torrents[ih]
if ok {
T.torrent.addTrackers(announceList)
} else {
T.torrent, err = newTorrent(ih, announceList, me.halfOpenLimit)
if err != nil {
return
}
me.torrents[ih] = T.torrent
if !me.disableTrackers {
go me.announceTorrentTrackers(T.torrent)
}
if me.dHT != nil {
go me.announceTorrentDHT(T.torrent, true)
}
T.torrent.pruneTimer = time.AfterFunc(0, func() {
me.pruneConnectionsUnlocked(T.torrent)
})
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}
return
}
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// Adds a torrent to the client.
func (me *Client) AddTorrent(metaInfo *metainfo.MetaInfo) (t Torrent, err error) {
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var ih InfoHash
CopyExact(&ih, metaInfo.Info.Hash)
me.mu.Lock()
defer me.mu.Unlock()
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t, err = me.addOrMergeTorrent(ih, metaInfo.AnnounceList)
if err != nil {
return
}
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if !t.torrent.haveInfo() {
err = me.setMetaData(t.torrent, metaInfo.Info.Info, metaInfo.Info.Bytes)
if err != nil {
return
}
}
return
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}
func (me *Client) AddTorrentFromFile(name string) (t Torrent, err error) {
mi, err := metainfo.LoadFromFile(name)
if err != nil {
err = fmt.Errorf("error loading metainfo from file: %s", err)
return
}
return me.AddTorrent(mi)
}
// Returns true when peers are required, or false if the torrent is closing.
func (cl *Client) waitWantPeers(t *torrent) bool {
cl.mu.Lock()
defer cl.mu.Unlock()
t.stateMu.Lock()
defer t.stateMu.Unlock()
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for {
select {
case <-t.ceasingNetworking:
return false
default:
}
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if len(t.Peers) < torrentPeersLowWater && t.needData() {
return true
}
cl.mu.Unlock()
t.wantPeers.Wait()
t.stateMu.Unlock()
cl.mu.Lock()
t.stateMu.Lock()
}
}
func (cl *Client) announceTorrentDHT(t *torrent, impliedPort bool) {
for cl.waitWantPeers(t) {
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log.Printf("getting peers for %q from DHT", t)
ps, err := cl.dHT.Announce(string(t.InfoHash[:]), cl.incomingPeerPort(), impliedPort)
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if err != nil {
log.Printf("error getting peers from dht: %s", err)
return
}
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allAddrs := make(map[string]struct{})
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getPeers:
for {
select {
case v, ok := <-ps.Values:
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if !ok {
break getPeers
}
peersFoundByDHT.Add(int64(len(v.Peers)))
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for _, p := range v.Peers {
allAddrs[(&net.UDPAddr{
IP: p.IP[:],
Port: int(p.Port),
}).String()] = struct{}{}
}
// log.Printf("%s: %d new peers from DHT", t, len(v.Peers))
cl.mu.Lock()
cl.addPeers(t, func() (ret []Peer) {
for _, cp := range v.Peers {
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ret = append(ret, Peer{
IP: cp.IP[:],
Port: int(cp.Port),
Source: peerSourceDHT,
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})
}
return
}())
numPeers := len(t.Peers)
cl.mu.Unlock()
if numPeers >= torrentPeersHighWater {
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break getPeers
}
case <-t.ceasingNetworking:
ps.Close()
return
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}
}
ps.Close()
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log.Printf("finished DHT peer scrape for %s: %d peers", t, len(allAddrs))
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}
}
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func (cl *Client) announceTorrentSingleTracker(tr tracker.Client, req *tracker.AnnounceRequest, t *torrent) error {
if err := tr.Connect(); err != nil {
return fmt.Errorf("error connecting: %s", err)
}
resp, err := tr.Announce(req)
if err != nil {
return fmt.Errorf("error announcing: %s", err)
}
var peers []Peer
for _, peer := range resp.Peers {
peers = append(peers, Peer{
IP: peer.IP,
Port: peer.Port,
})
}
err = cl.AddPeers(t.InfoHash, peers)
if err != nil {
log.Printf("error adding peers to torrent %s: %s", t, err)
} else {
log.Printf("%s: %d new peers from %s", t, len(peers), tr)
}
time.Sleep(time.Second * time.Duration(resp.Interval))
return nil
}
func (cl *Client) announceTorrentTrackersFastStart(req *tracker.AnnounceRequest, trackers [][]tracker.Client, t *torrent) (atLeastOne bool) {
oks := make(chan bool)
outstanding := 0
for _, tier := range trackers {
for _, tr := range tier {
outstanding++
go func(tr tracker.Client) {
err := cl.announceTorrentSingleTracker(tr, req, t)
oks <- err == nil
}(tr)
}
}
for outstanding > 0 {
ok := <-oks
outstanding--
if ok {
atLeastOne = true
}
}
return
}
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// Announce torrent to its trackers.
func (cl *Client) announceTorrentTrackers(t *torrent) {
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req := tracker.AnnounceRequest{
Event: tracker.Started,
NumWant: -1,
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Port: int16(cl.incomingPeerPort()),
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PeerId: cl.peerID,
InfoHash: t.InfoHash,
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}
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if !cl.waitWantPeers(t) {
return
}
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cl.mu.RLock()
req.Left = t.BytesLeft()
trackers := t.Trackers
cl.mu.RUnlock()
if cl.announceTorrentTrackersFastStart(&req, trackers, t) {
req.Event = tracker.None
}
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newAnnounce:
for cl.waitWantPeers(t) {
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cl.mu.RLock()
req.Left = t.BytesLeft()
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trackers = t.Trackers
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cl.mu.RUnlock()
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numTrackersTried := 0
for _, tier := range trackers {
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for trIndex, tr := range tier {
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numTrackersTried++
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err := cl.announceTorrentSingleTracker(tr, &req, t)
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if err != nil {
continue
}
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// Float the successful announce to the top of the tier. If
// the trackers list has been changed, we'll be modifying an
// old copy so it won't matter.
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cl.mu.Lock()
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tier[0], tier[trIndex] = tier[trIndex], tier[0]
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cl.mu.Unlock()
req.Event = tracker.None
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continue newAnnounce
}
}
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if numTrackersTried != 0 {
log.Printf("%s: all trackers failed", t)
}
// TODO: Wait until trackers are added if there are none.
time.Sleep(10 * time.Second)
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}
}
func (cl *Client) allTorrentsCompleted() bool {
for _, t := range cl.torrents {
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if !t.haveInfo() {
return false
}
if t.NumPiecesCompleted() != t.numPieces() {
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return false
}
}
return true
}
// Returns true when all torrents are completely downloaded and false if the
// client is stopped before that.
func (me *Client) WaitAll() bool {
me.mu.Lock()
defer me.mu.Unlock()
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for !me.allTorrentsCompleted() {
if me.stopped() {
return false
}
me.event.Wait()
}
return true
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}
func (me *Client) replenishConnRequests(t *torrent, c *connection) {
if !t.haveInfo() {
return
}
me.downloadStrategy.FillRequests(t, c)
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if len(c.Requests) == 0 && !c.PeerChoked {
c.SetInterested(false)
}
}
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// Handle a received chunk from a peer.
func (me *Client) downloadedChunk(t *torrent, c *connection, msg *pp.Message) error {
chunksDownloadedCount.Add(1)
req := newRequest(msg.Index, msg.Begin, pp.Integer(len(msg.Piece)))
// Request has been satisfied.
me.connDeleteRequest(t, c, req)
defer me.replenishConnRequests(t, c)
// Do we actually want this chunk?
if _, ok := t.Pieces[req.Index].PendingChunkSpecs[req.chunkSpec]; !ok {
unusedDownloadedChunksCount.Add(1)
c.UnwantedChunksReceived++
return nil
}
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c.UsefulChunksReceived++
c.lastUsefulChunkReceived = time.Now()
// Write the chunk out.
err := t.WriteChunk(int(msg.Index), int64(msg.Begin), msg.Piece)
if err != nil {
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return fmt.Errorf("error writing chunk: %s", err)
}
// Record that we have the chunk.
delete(t.Pieces[req.Index].PendingChunkSpecs, req.chunkSpec)
if len(t.Pieces[req.Index].PendingChunkSpecs) == 0 {
for _, c := range t.Conns {
c.pieceRequestOrder.DeletePiece(int(req.Index))
}
me.queuePieceCheck(t, req.Index)
}
// Unprioritize the chunk.
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me.downloadStrategy.TorrentGotChunk(t, req)
// Cancel pending requests for this chunk.
for _, c := range t.Conns {
if me.connCancel(t, c, req) {
me.replenishConnRequests(t, c)
}
}
me.downloadStrategy.AssertNotRequested(t, req)
return nil
}
func (me *Client) pieceHashed(t *torrent, piece pp.Integer, correct bool) {
p := t.Pieces[piece]
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if p.EverHashed && !correct {
log.Printf("%s: piece %d failed hash", t, piece)
failedPieceHashes.Add(1)
}
p.EverHashed = true
if correct {
p.Priority = piecePriorityNone
p.PendingChunkSpecs = nil
p.Event.Broadcast()
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me.downloadStrategy.TorrentGotPiece(t, int(piece))
} else {
if len(p.PendingChunkSpecs) == 0 {
t.pendAllChunkSpecs(piece)
}
if p.Priority != piecePriorityNone {
me.openNewConns(t)
}
}
for _, conn := range t.Conns {
if correct {
conn.Post(pp.Message{
Type: pp.Have,
Index: pp.Integer(piece),
})
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// TODO: Cancel requests for this piece.
for r := range conn.Requests {
if r.Index == piece {
panic("wat")
}
}
conn.pieceRequestOrder.DeletePiece(int(piece))
}
if t.wantPiece(int(piece)) && conn.PeerHasPiece(piece) {
t.connPendPiece(conn, int(piece))
me.replenishConnRequests(t, conn)
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}
}
if t.haveAllPieces() && me.noUpload {
t.ceaseNetworking()
}
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me.event.Broadcast()
}
func (cl *Client) verifyPiece(t *torrent, index pp.Integer) {
cl.mu.Lock()
defer cl.mu.Unlock()
p := t.Pieces[index]
for p.Hashing || t.data == nil {
cl.event.Wait()
}
if t.isClosed() {
return
}
p.Hashing = true
p.QueuedForHash = false
cl.mu.Unlock()
sum := t.HashPiece(index)
cl.mu.Lock()
select {
case <-t.closing:
return
default:
}
p.Hashing = false
cl.pieceHashed(t, index, sum == p.Hash)
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}
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func (me *Client) Torrents() (ret []Torrent) {
me.mu.Lock()
for _, t := range me.torrents {
ret = append(ret, Torrent{me, t})
}
me.mu.Unlock()
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return
}