Golang Packet.Header方法代碼示例

func (t *transport) handlePing(ch *e3x.Channel) {
	var (
		err   error
		pkt   *lob.Packet
		id    string
		alive bool
	)

	defer ch.Close()

	pkt, err = ch.ReadPacket()
	if err != nil {
		// log error
		// tracef("error: %s", err)
		return
	}

	id, _ = pkt.Header().GetString("vn")
	rpc := t.lookupRPC(id)
	if rpc == nil {
		alive = false
	} else {
		alive = true
	}

	pkt = &lob.Packet{}
	pkt.Header().SetBool("alive", alive)
	err = ch.WritePacket(pkt)
	if err != nil {
		// log error
		// tracef("error: %s", err)
		return
	}
}

func (c *Channel) traceReceivedPacket(pkt *lob.Packet) {
	if tracer.Enabled {
		tracer.Emit("channel.rcv.packet", tracer.Info{
			"channel_id": c.TID,
			"packet_id":  pkt.TID,
			"packet": tracer.Info{
				"header": pkt.Header(),
				"body":   base64.StdEncoding.EncodeToString(pkt.Body(nil)),
			},
		})
	}
}

func (t *transport) handleGetPredecessor(ch *e3x.Channel) {
	var (
		err   error
		pkt   *lob.Packet
		id    string
		vnode *chord.Vnode
		res   *completeVnode
	)

	defer ch.Close()

	pkt, err = ch.ReadPacket()
	if err != nil {
		// log error
		// tracef("error: %s", err)
		return
	}

	id, _ = pkt.Header().GetString("vn")
	rpc := t.lookupRPC(id)
	if rpc == nil {
		// log
		// tracef("error: %s", "no RPC")
		return
	}

	vnode, err = rpc.GetPredecessor()
	if err != nil {
		// log
		// tracef("error: %s", err)
		return
	}

	res = t.completeVnode(vnode)
	err = json.NewEncoder(newStream(ch)).Encode(&res)
	if err != nil {
		// log
		// tracef("error: %s", err)
		return
	}

	if res != nil {
		// tracef("handle.GetPredecessor(Vnode(%q)) => Vnode(%q)", id, res.Id)
	}
}

func (c *Channel) traceDroppedPacket(pkt *lob.Packet, reason string) {
	if tracer.Enabled {
		info := tracer.Info{
			"channel_id": c.TID,
			"packet_id":  pkt.TID,
			"reason":     reason,
		}

		if pkt != nil {
			info["packet"] = tracer.Info{
				"header": pkt.Header(),
				"body":   base64.StdEncoding.EncodeToString(pkt.Body(nil)),
			}
		}

		tracer.Emit("channel.rcv.packet", info)
	}
}

func (c *Channel) applyAckHeaders(pkt *lob.Packet) {
	if !c.reliable {
		return
	}

	if c.iSeq == cBlankSeq {
		// nothin to ack
		return
	}

	hdr := pkt.Header()
	if c.iSeq >= cInitialSeq {
		hdr.Ack, hdr.HasAck = c.iSeq, true
	}
	if l := c.buildMissList(); len(l) > 0 {
		hdr.Miss, hdr.HasMiss = l, true
	}

	c.iAckedSeq = c.iSeq
}

// Request a nodes predecessor
func (t *transport) GetPredecessor(vn *chord.Vnode) (*chord.Vnode, error) {
	var (
		addr *e3x.Addr
		ch   *e3x.Channel
		pkt  *lob.Packet
		res  *completeVnode
		err  error
	)

	addr = t.lookupAddr(hashname.H(vn.Host))
	if addr == nil {
		return nil, e3x.ErrNoAddress
	}

	ch, err = t.e.Open(addr, "chord.predecessor.get", true)
	if err != nil {
		return nil, err
	}

	defer ch.Close()

	// ch.SetReadDeadline(time.Now().Add(30*time.Second))
	// ch.SetWriteDeadline(time.Now().Add(30*time.Second))

	pkt = &lob.Packet{}
	pkt.Header().SetString("vn", vn.String())
	err = ch.WritePacket(pkt)
	if err != nil {
		return nil, err
	}

	err = json.NewDecoder(newStream(ch)).Decode(&res)
	if err != nil {
		return nil, err
	}

	if res != nil {
		// tracef("GetPredecessor(Vnode(%q)) => Vnode(%q)", vn.String(), res.Id)
	}
	return t.internalVnode(res), nil
}

func (c *Channel) traceWrite(pkt *lob.Packet, p *Pipe) {
	if tracer.Enabled {
		info := tracer.Info{
			"channel_id": c.TID,
		}

		if p != nil {
			info["path"] = p.RemoteAddr().String()
		}

		if pkt != nil {
			info["packet_id"] = pkt.TID
			info["packet"] = tracer.Info{
				"header": pkt.Header(),
				"body":   base64.StdEncoding.EncodeToString(pkt.Body(nil)),
			}
		}

		tracer.Emit("channel.write", info)
	}
}

// Ping a Vnode, check for liveness
func (t *transport) Ping(vn *chord.Vnode) (bool, error) {
	var (
		addr  *e3x.Addr
		ch    *e3x.Channel
		pkt   *lob.Packet
		alive bool
		err   error
	)

	addr = t.lookupAddr(hashname.H(vn.Host))
	if addr == nil {
		return false, e3x.ErrNoAddress
	}

	ch, err = t.e.Open(addr, "chord.ping", true)
	if err != nil {
		return false, err
	}

	defer ch.Close()

	// ch.SetReadDeadline(time.Now().Add(30*time.Second))
	// ch.SetWriteDeadline(time.Now().Add(30*time.Second))

	pkt = &lob.Packet{}
	pkt.Header().SetString("vn", vn.String())
	err = ch.WritePacket(pkt)
	if err != nil {
		return false, err
	}

	pkt, err = ch.ReadPacket()
	if err != nil {
		return false, err
	}
	alive, _ = pkt.Header().GetBool("alive")
	// tracef("Ping(Vnode(%q)) => %v", vn.String(), alive)
	return alive, nil
}

func (c *Channel) traceWriteError(pkt *lob.Packet, p *Pipe, reason error) error {
	if tracer.Enabled {
		info := tracer.Info{
			"channel_id": c.TID,
			"reason":     reason.Error(),
		}

		if p != nil {
			info["path"] = p.RemoteAddr().String()
		}

		if pkt != nil {
			info["packet_id"] = pkt.TID
			info["packet"] = tracer.Info{
				"header": pkt.Header(),
				"body":   base64.StdEncoding.EncodeToString(pkt.Body(nil)),
			}
		}

		tracer.Emit("channel.write.error", info)
	}
	return reason
}

func TestBridge(t *testing.T) {
	// given:
	// A <-> B exchange
	// B <-> R exchange
	// A x-x R no exchange
	//
	// when:
	// R --> B route token from A->B to B
	// A --x B block A from contacting B (while adding R's addresses to the exchange A->B)
	//
	// then:
	// A and B should still be able to communicate.

	assert := assert.New(t)

	var blacklist []net.Addr
	blacklistRule := func(src net.Addr) bool {
		t.Logf("FW(%v, src=%s)", blacklist, src)
		if len(blacklist) == 0 {
			return true
		}

		for _, addr := range blacklist {
			if transports.EqualAddr(addr, src) {
				return false
			}
		}

		return true
	}

	A, err := e3x.Open(
		e3x.Log(nil),
		e3x.Transport(udp.Config{}),
		Module(Config{}))
	assert.NoError(err)
	B, err := e3x.Open(
		e3x.Log(nil),
		e3x.Transport(fw.Config{Config: udp.Config{}, Allow: fw.RuleFunc(blacklistRule)}),
		Module(Config{}))
	assert.NoError(err)

	R, err := e3x.Open(
		e3x.Log(nil),
		e3x.Transport(udp.Config{}),
		Module(Config{}))
	assert.NoError(err)

	done := make(chan bool, 1)

	go func() {

		var (
			pkt   *lob.Packet
			err   error
			n     = 1
			first = true
		)

		defer func() { done <- true }()

		c, err := A.Listen("ping", true).AcceptChannel()
		defer c.Close()

		for ; n > 0; n-- {
			pkt, err = c.ReadPacket()
			if err != nil {
				t.Fatalf("ping: error: %s", err)
				return
			}

			if first {
				n, _ = pkt.Header().GetInt("n")
				first = false
			}

			t.Logf("RCV ping: %d", n)

			err = c.WritePacket(&lob.Packet{})
			if err != nil {
				t.Fatalf("ping: error: %s", err)
				return
			}

			t.Logf("SND pong: %d", n)
		}
	}()

	Aident, err := A.LocalIdentity()
	assert.NoError(err)
	Bident, err := B.LocalIdentity()
	assert.NoError(err)

	{
		addr, err := transports.ResolveAddr("peer", string(R.LocalHashname()))
		assert.NoError(err)
		Bident = Bident.AddPathCandiate(addr)
	}

	log.Println("\x1B[31m------------------------------------------------\x1B[0m")
//.........這裏部分代碼省略.........

func (s *state) DecryptPacket(pkt *lob.Packet) (*lob.Packet, error) {
	s.mtx.RLock()
	defer s.mtx.RUnlock()

	if !s.CanDecryptPacket() {
		return nil, cipherset.ErrInvalidState
	}
	if pkt == nil {
		return nil, nil
	}

	if !pkt.Header().IsZero() || pkt.BodyLen() < 16+4+4 {
		return nil, cipherset.ErrInvalidPacket
	}

	var (
		nonce    [16]byte
		bodyRaw  []byte
		innerRaw []byte
		innerLen = pkt.BodyLen() - (16 + 4 + 4)
		body     = bufpool.New()
		inner    = bufpool.New().SetLen(innerLen)
	)

	pkt.Body(body.SetLen(pkt.BodyLen()).RawBytes()[:0])
	bodyRaw = body.RawBytes()
	innerRaw = inner.RawBytes()

	// compare token
	if !bytes.Equal(bodyRaw[:16], (*s.localToken)[:]) {
		inner.Free()
		body.Free()
		return nil, cipherset.ErrInvalidPacket
	}

	// copy nonce
	copy(nonce[:], bodyRaw[16:16+4])

	{ // verify hmac
		mac := bodyRaw[16+4+innerLen:]

		macKey := append(s.lineDecryptionKey, nonce[:4]...)

		h := hmac.New(sha256.New, macKey)
		h.Write(bodyRaw[16+4 : 16+4+innerLen])
		if subtle.ConstantTimeCompare(mac, fold(h.Sum(nil), 4)) != 1 {
			inner.Free()
			body.Free()
			return nil, cipherset.ErrInvalidPacket
		}
	}

	{ // decrypt inner
		aesBlock, err := aes.NewCipher(s.lineDecryptionKey)
		if err != nil {
			inner.Free()
			body.Free()
			return nil, err
		}

		aes := Cipher.NewCTR(aesBlock, nonce[:])
		if aes == nil {
			inner.Free()
			body.Free()
			return nil, cipherset.ErrInvalidPacket
		}

		aes.XORKeyStream(innerRaw, bodyRaw[16+4:16+4+innerLen])
	}

	innerPkt, err := lob.Decode(inner)
	if err != nil {
		inner.Free()
		body.Free()
		return nil, err
	}

	inner.Free()
	body.Free()

	return innerPkt, nil
}

func (s *cipherTestSuite) TestPacketEncryption() {
	var (
		assert = s.Assertions
		c      = s.cipher
	)

	var (
		ka  cipherset.Key
		kb  cipherset.Key
		sa  cipherset.State
		sb  cipherset.State
		ha  cipherset.Handshake
		hb  cipherset.Handshake
		pkt *lob.Packet
		box []byte
		err error
		ok  bool
	)

	ka, err = c.GenerateKey()
	assert.NoError(err)
	kb, err = c.GenerateKey()
	assert.NoError(err)

	sa, err = c.NewState(ka)
	assert.NoError(err)
	sb, err = c.NewState(kb)
	assert.NoError(err)

	err = sa.SetRemoteKey(kb)
	assert.NoError(err)
	box, err = sa.EncryptHandshake(1, nil)
	assert.NoError(err)
	hb, err = c.DecryptHandshake(kb, box)
	assert.NoError(err)
	ok = sb.ApplyHandshake(hb)
	assert.True(ok)
	box, err = sb.EncryptHandshake(1, nil)
	assert.NoError(err)
	ha, err = c.DecryptHandshake(ka, box)
	assert.NoError(err)
	ok = sa.ApplyHandshake(ha)
	assert.True(ok)

	pkt = lob.New([]byte("Hello world!"))
	pkt.Header().SetInt("foo", 0xbeaf)
	pkt, err = sa.EncryptPacket(pkt)
	assert.NoError(err)
	assert.NotNil(pkt)
	assert.Nil(pkt.Header().Bytes)
	assert.True(pkt.Header().IsZero())
	assert.NotEmpty(pkt.Body)

	pkt, err = sb.DecryptPacket(pkt)
	assert.NoError(err)
	assert.NotNil(pkt)
	assert.Nil(pkt.Header().Bytes)
	assert.Equal(&lob.Header{Extra: map[string]interface{}{"foo": 0xbeaf}}, pkt.Header())
	assert.Equal([]byte("Hello world!"), pkt.Body(nil))

	pkt = lob.New([]byte("Bye world!"))
	pkt.Header().SetInt("bar", 0xdead)
	pkt, err = sb.EncryptPacket(pkt)
	assert.NoError(err)
	assert.NotNil(pkt)
	assert.Nil(pkt.Header().Bytes)
	assert.True(pkt.Header().IsZero())
	assert.NotEmpty(pkt.Body)

	pkt, err = sa.DecryptPacket(pkt)
	assert.NoError(err)
	assert.NotNil(pkt)
	assert.Nil(pkt.Header().Bytes)
	assert.Equal(&lob.Header{Extra: map[string]interface{}{"bar": 0xdead}}, pkt.Header())
	assert.Equal([]byte("Bye world!"), pkt.Body(nil))
}

func (s *state) DecryptPacket(pkt *lob.Packet) (*lob.Packet, error) {
	s.mtx.RLock()
	defer s.mtx.RUnlock()

	if !s.CanDecryptPacket() {
		return nil, cipherset.ErrInvalidState
	}
	if pkt == nil {
		return nil, nil
	}

	if !pkt.Header().IsZero() || pkt.BodyLen() < lenToken+lenNonce {
		return nil, cipherset.ErrInvalidPacket
	}

	var (
		nonce    [lenNonce]byte
		bodyRaw  []byte
		innerRaw []byte
		innerPkt *lob.Packet
		body     = bufpool.New()
		inner    = bufpool.New()
		ok       bool
	)

	pkt.Body(body.SetLen(pkt.BodyLen()).RawBytes()[:0])
	bodyRaw = body.RawBytes()
	innerRaw = inner.RawBytes()

	// compare token
	if !bytes.Equal(bodyRaw[:lenToken], (*s.localToken)[:]) {
		inner.Free()
		body.Free()
		return nil, cipherset.ErrInvalidPacket
	}

	// copy nonce
	copy(nonce[:], bodyRaw[lenToken:lenToken+lenNonce])

	// decrypt inner packet
	innerRaw, ok = box.OpenAfterPrecomputation(
		innerRaw[:0], bodyRaw[lenToken+lenNonce:], &nonce, s.lineDecryptionKey)
	if !ok {
		inner.Free()
		body.Free()
		return nil, cipherset.ErrInvalidPacket
	}
	inner.SetLen(len(innerRaw))

	innerPkt, err := lob.Decode(inner)
	if err != nil {
		inner.Free()
		body.Free()
		return nil, err
	}

	inner.Free()
	body.Free()

	return innerPkt, nil
}

func (c *Channel) receivedPacket(pkt *lob.Packet) {
	const (
		errBrokenChannel   = "broken channel"
		errMissingSeq      = "missing seq"
		errDuplicatePacket = "duplicate packet"
		errFullBuffer      = "full buffer"
	)

	c.mtx.Lock()

	if c.broken {
		c.mtx.Unlock()
		c.traceDroppedPacket(pkt, errBrokenChannel)
		statChannelRcvPktDrop.Add(1)
		return
	}

	var (
		hdr           = pkt.Header()
		seq, hasSeq   = hdr.Seq, hdr.HasSeq
		ack, hasAck   = hdr.Ack, hdr.HasAck
		miss, hasMiss = hdr.Miss, hdr.HasMiss
		end, hasEnd   = hdr.End, hdr.HasEnd
	)

	if !c.reliable {
		// unreliable channels (internaly) emulate reliable channels.
		seq = c.iBufferedSeq + 1
		hasSeq = true

	} else {
		// determine what to drop from the write buffer
		if hasAck {
			if hasSeq {
				statChannelRcvAckInline.Add(1)
			} else {
				statChannelRcvAckAdHoc.Add(1)
			}

			var (
				oldAck  = c.oAckedSeq
				changed bool
			)

			if c.oAckedSeq < ack {
				c.oAckedSeq = ack
				changed = true
			}

			for i := oldAck + 1; i <= ack; i++ {
				if e := c.writeBuffer[i]; e != nil {
					e.pkt.Free()
				}
				delete(c.writeBuffer, i)
				changed = true
			}

			if len(c.writeBuffer) == 0 {
				c.needsResend = false
			}

			if changed {
				c.cndWrite.Signal()
				if c.deliveredEnd || c.receivedEnd {
					c.cndClose.Signal()
				}
			}

			if hasMiss {
				c.processMissingPackets(ack, miss)
			}
		}
	}

	if !hasSeq {
		// drop: is not a valid packet
		c.mtx.Unlock()
		c.traceDroppedPacket(pkt, errMissingSeq)

		if !hasAck {
			statChannelRcvPktDrop.Add(1)
		}

		return
	}

	if c.reliable && c.iSeenSeq < seq {
		// record highest seen seq
		c.iSeenSeq = seq
	}

	if seq <= c.iSeq {
		// drop: the reader already read a packet with this seq
		c.mtx.Unlock()
		c.traceDroppedPacket(pkt, errDuplicatePacket)
		statChannelRcvPktDrop.Add(1)
		return
	}

	if len(c.readBuffer) >= cReadBufferSize {
//.........這裏部分代碼省略.........

func (c *Channel) write(pkt *lob.Packet, p *Pipe) error {
	if pkt.TID == 0 {
		pkt.TID = tracer.NewID()
	}

	if c.broken {
		// When a channel is marked as broken the all writes
		// must return a BrokenChannelError.
		return c.traceWriteError(pkt, p,
			&BrokenChannelError{c.hashname, c.typ, c.id})
	}

	if c.writeDeadlineReached {
		// When a channel reached a write deadline then all writes
		// must return a ErrTimeout.
		return c.traceWriteError(pkt, p,
			ErrTimeout)
	}

	if c.deliveredEnd {
		// When a channel sent a packet with the "end" header set
		// then all subsequent writes must return io.EOF
		return c.traceWriteError(pkt, p,
			io.EOF)
	}

	c.oSeq++
	hdr := pkt.Header()
	hdr.C, hdr.HasC = c.id, true
	if c.reliable {
		hdr.Seq, hdr.HasSeq = c.oSeq, true
	}
	if !c.serverside && c.oSeq == cInitialSeq {
		hdr.Type, hdr.HasType = c.typ, true
	}

	end := hdr.HasEnd && hdr.End
	if end {
		c.deliveredEnd = true
		c.setCloseDeadline()
	}

	if c.reliable {
		if c.oSeq%30 == 0 || hdr.End {
			c.applyAckHeaders(pkt)
		}
		c.writeBuffer[c.oSeq] = &writeBufferEntry{pkt, end, time.Time{}, p}
		c.needsResend = false
	}

	err := c.x.deliverPacket(pkt, p)
	if err != nil {
		return c.traceWriteError(pkt, p, err)
	}
	statChannelSndPkt.Add(1)
	if pkt.Header().HasAck {
		statChannelSndAckInline.Add(1)
	}

	if c.oSeq == cInitialSeq && c.serverside {
		c.unsetOpenDeadline()
	}

	c.traceWrite(pkt, p)

	if !c.reliable {
		pkt.Free()
	}

	return nil
}