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peerWireProto.go
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/
peerWireProto.go
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package Torrent
import (
"bytes"
"encoding/binary"
"errors"
tracker "github.com/JRonak/Torrent/Tracker"
"log"
"net"
"sync"
"time"
)
const (
RETRYCOUNT = 1
BLOCKSIZE = 65536
MAXMEMORY = 1024 * 1024 * 10
)
const (
CHOKED = iota
UNCHOKED
INTERESTED
UNINTERESTED
HAVE
BITFIELD
REQUEST
PIECE
)
type Piece struct {
Id int //Index of the piece
BlockSize int //Size of the block
PieceSize int //Size of the piece
Offset int //Offset in the piece
Data *bytes.Buffer //Downloaded piece
Stamp time.Time
Lock sync.Mutex
}
type PieceRequest struct {
Id int32 //Index of the piece
Offset int32 //Offset of the piece
Size int32 //Block size to be downloaded or uploaded
}
type PeerClient struct {
Conn net.Conn
PeerId [20]byte
manager *Manager
piece Piece
peerInterested bool
peerChoked bool
selfInterested bool
selfChoked bool
piecesAvailable BitArray
writeChan chan []byte
}
type HandshakeData struct {
NameLength byte
Protocol [19]byte
Reserved [8]byte
Infohash [20]byte
PeerId [20]byte
}
func (this *PeerClient) Init() {
this.writeChan = make(chan []byte, 10)
this.piecesAvailable.bits = 0
this.piece.Id = -1
this.piece.Offset = 0
this.piece.Data = bytes.NewBuffer(nil)
}
func (this *PeerClient) Close() {
close(this.writeChan)
this.manager = nil
if this.Conn != nil {
this.Conn.Close()
}
this.piece.Data.Reset()
}
func (this *PeerClient) Connect(peer tracker.Peer) {
con, err := net.DialTimeout("tcp", Address(peer.Ip, peer.Port), time.Second*10)
if err != nil {
return
}
this.Conn = con
h := HandshakeData{}
h.Infohash = this.manager.InfoHash
h.NameLength = 19
h.PeerId = this.manager.PeerId
s := "BitTorrent protocol"
for i := 0; i < 19; i++ {
h.Protocol[i] = byte(s[i])
}
err = binary.Write(this.Conn, binary.LittleEndian, h)
if err != nil {
// log.Println("1:", err)
return
}
data, err := this.read(68, time.Second*10)
if err != nil {
// log.Println("2:", err)
return
}
buf := bytes.NewBuffer(data)
response := HandshakeData{}
err = binary.Read(buf, binary.LittleEndian, &response)
if err != nil {
// log.Println("3:", err)
return
}
if response.Infohash != h.Infohash {
//log.Println("hash fail")
return
}
this.PeerId = response.PeerId
this.Init()
if this.manager.registerPeer(this) == false {
this.Close()
return
}
go this.write()
//log.Println("connected")
this.sendBitField()
this.HandleResponse()
}
func (this *PeerClient) BitField(size int) {
if size <= 0 {
return
}
data, err := this.read(size, time.Second*5)
if err != nil {
return
}
this.piecesAvailable.Set(data)
this.SendInterested()
this.manager.findPiece(this)
}
//Incomplete function
//Receives 12 byte piece info
func (this *PeerClient) Request() {
data, err := this.read(12, time.Second*5)
if err != nil {
return
}
buffer := bytes.NewBuffer(data)
p := PieceRequest{}
err = binary.Read(buffer, binary.BigEndian, &p)
if err != nil {
return
}
this.SendPiece(int(p.Id), int(p.Offset), int(p.Size))
}
func (this *PeerClient) Have() {
data, err := this.read(4, time.Second*5)
if err != nil {
return
}
var x int32
buffer := bytes.NewBuffer(data)
binary.Read(buffer, binary.BigEndian, &x)
this.piecesAvailable.LockPiece(int(x))
}
func (this *PeerClient) Piece(size int) {
data, err := this.read(size, time.Second*15)
if err != nil {
return
}
buffer := bytes.NewBuffer(data[:8])
type temp struct {
Id int32
Offset int32
}
t := temp{}
err = binary.Read(buffer, binary.BigEndian, &t)
if err != nil {
return
}
if int(t.Id) == this.piece.Id && int(t.Offset) == this.piece.Offset {
this.piece.Data.Write(data[8:])
this.piece.Offset += len(data[8:])
this.managePieceDownload()
}
}
func (this *PeerClient) SendInterested() {
this.writeChan <- []byte{INTERESTED}
this.selfInterested = true
}
func (this *PeerClient) SendUninterested() {
this.writeChan <- []byte{UNINTERESTED}
this.selfInterested = false
}
func (this *PeerClient) SendChoked() {
this.writeChan <- []byte{CHOKED}
this.peerChoked = true
}
func (this *PeerClient) SendUnchoked() {
this.writeChan <- []byte{UNCHOKED}
this.peerChoked = false
}
func (this *PeerClient) SendPieceRquest() {
if !this.selfInterested {
this.SendInterested()
}
p := PieceRequest{
Size: int32(this.piece.BlockSize),
Id: int32(this.piece.Id),
Offset: int32(this.piece.Offset)}
buf := bytes.NewBuffer([]byte{REQUEST})
err := binary.Write(buf, binary.BigEndian, p)
if err != nil {
return
}
this.writeChan <- buf.Bytes()
}
func (this *PeerClient) sendHave(index int) {
buf := bytes.NewBuffer([]byte{HAVE})
i := int32(index)
err := binary.Write(buf, binary.BigEndian, i)
if err != nil {
return
}
this.writeChan <- buf.Bytes()
}
func (this *PeerClient) sendBitField() {
if this.manager.Stats.AvailablePieces == 0 {
return
}
buf := bytes.NewBuffer([]byte{BITFIELD})
buf.Write(this.manager.Blocks.AvailablePieces.GetArray())
this.writeChan <- buf.Bytes()
buf.Reset()
}
func (this *PeerClient) SendPiece(index, offset, size int) {
if !this.manager.Blocks.AvailablePieces.IsLocked(index) {
return
}
if this.peerChoked {
return
}
data := this.manager.Storage.GetBlock(index, offset, size)
type temp struct {
Id int32
Offset int32
}
t := temp{Id: int32(index), Offset: int32(offset)}
buffer := bytes.NewBuffer(nil)
err := binary.Write(buffer, binary.BigEndian, t)
if err != nil {
return
}
buffer.Write(data)
this.writeChan <- buffer.Bytes()
this.manager.Stats.PieceChan <- UPLOADEDPIECE
}
func (this *PeerClient) write() {
for data := range this.writeChan {
length := int32(len(data))
conn := this.Conn
err := binary.Write(conn, binary.BigEndian, length)
if err != nil {
return
}
size := len(data)
this.manager.Stats.UploadChan <- (size + 4)
for count := 0; count < size; {
n, err := conn.Write(data[(count):])
if err != nil {
return
}
count += n
}
}
}
func (this *PeerClient) read(length int, duration time.Duration) ([]byte, error) {
if length <= 0 {
return nil, errors.New("Invalid length")
} else if length > MAXMEMORY {
log.Println("Requesting high memory!", length)
this.manager.unresgisterPeer(this)
return nil, errors.New("Invalid Size")
}
conn := this.Conn
count := length
databuffer := bytes.NewBuffer(nil)
for count != 0 {
err := conn.SetReadDeadline(time.Now().Add(duration))
if err != nil {
return nil, err
}
buffer := make([]byte, count)
n, err := conn.Read(buffer)
if err != nil {
return nil, err
}
n, err = databuffer.Write(buffer[:n])
if err != nil {
return nil, err
}
count -= n
this.manager.Stats.DownloadChan <- n
}
return databuffer.Bytes(), nil
}
// Handles all the Peer Wire protocol messages
func (this *PeerClient) HandleResponse() {
for {
data, err := this.read(5, time.Second*1000)
if err != nil {
break
}
buffer := bytes.NewBuffer(data[:4])
var size int32
binary.Read(buffer, binary.BigEndian, &size)
switch data[4] {
case CHOKED:
this.selfChoked = true
case UNCHOKED:
this.selfChoked = false
case INTERESTED:
this.peerInterested = true
if this.peerChoked {
this.SendUnchoked()
}
case UNINTERESTED:
this.peerInterested = false
case HAVE:
this.Have()
case BITFIELD:
this.BitField(int(size - 1))
case REQUEST:
this.Request()
case PIECE:
this.Piece(int(size - 1))
default:
break
}
}
this.manager.unresgisterPeer(this)
}
func (this *PeerClient) managePieceDownload() {
if this.piece.PieceSize == this.piece.Offset {
data := this.piece.Data.Bytes()
go this.manager.StorePiece(this.piece.Id, &data)
this.piece.Lock.Lock()
this.piece.Id = -1
this.piece.Data.Reset()
this.piece.Offset = 0
this.piece.Lock.Unlock()
this.manager.Stats.PieceChan <- DELETE_ACTIVE_PEER
this.manager.findPiece(this)
} else {
this.piece.Lock.Lock()
this.piece.Stamp = time.Now()
size := this.piece.PieceSize - this.piece.Offset
if size >= BLOCKSIZE {
this.piece.BlockSize = BLOCKSIZE
} else {
this.piece.BlockSize = size
}
this.piece.Lock.Unlock()
this.SendPieceRquest()
}
}