fix: wrong drop of same crc packet

gold/link/crypto.go

@@ -121,12 +121,13 @@ func decode(aead cipher.AEAD, additional uint16, b []byte) ([]byte, error) {
 }
 
 // xorenc 按 8 字节, 以初始 m.mask 循环异或编码 data
-func (m *Me) xorenc(data []byte) []byte {
+func (m *Me) xorenc(data []byte, seq uint32) []byte {
 	batchsz := len(data) / 8
 	remain := len(data) % 8
 	sum := m.mask
 	newdat := helper.MakeBytes(len(data) + 8)
-	_, _ = rand.Read(newdat[:8])
+	binary.LittleEndian.PutUint32(newdat[:4], seq)
+	_, _ = rand.Read(newdat[4:8])
 	if remain > 0 {
 		var buf [8]byte
 		p := batchsz * 8
@@ -141,13 +142,15 @@ func (m *Me) xorenc(data []byte) []byte {
 		sum ^= binary.LittleEndian.Uint64(data[a:b])
 		binary.LittleEndian.PutUint64(newdat[a+8:b+8], sum)
 	}
+	sum ^= binary.LittleEndian.Uint64(newdat[:8])
+	binary.LittleEndian.PutUint64(newdat[:8], sum)
 	return newdat
 }
 
 // xordec 按 8 字节, 以初始 m.mask 循环异或解码 data
-func (m *Me) xordec(data []byte) []byte {
+func (m *Me) xordec(data []byte) (uint32, []byte) {
 	if len(data) <= 8 {
-		return nil
+		return 0, nil
 	}
 	batchsz := len(data) / 8
 	remain := len(data) % 8
@@ -178,5 +181,5 @@ func (m *Me) xordec(data []byte) []byte {
 	} else {
 		binary.LittleEndian.PutUint64(data[len(data)-8:], next^m.mask)
 	}
-	return data[8:]
+	return binary.LittleEndian.Uint32(data[:4]), data[8:]
 }

gold/link/crypto_test.go

@@ -27,8 +27,9 @@ func TestXOR(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if !bytes.Equal(m.xordec(m.xorenc(r1.Bytes())), r2.Bytes()) {
-			t.Fatal("unexpected xor at", i)
+		seq, dec := m.xordec(m.xorenc(r1.Bytes(), uint32(i)))
+		if !bytes.Equal(dec, r2.Bytes()) || seq != uint32(i) {
+			t.Fatal("unexpected xor at", i, "seq", seq)
 		}
 	}
 }

gold/link/me.go

@@ -42,7 +42,7 @@ type Me struct {
 	// 本机路由表
 	router *Router
 	// 本机未接收完全分片池
-	recving *ttl.Cache[[32]byte, *head.Packet]
+	recving *ttl.Cache[uint64, *head.Packet]
 	// 抗重放攻击记录池
 	recved *ttl.Cache[uint64, bool]
 	// 本机上层配置
@@ -106,7 +106,7 @@ func NewMe(cfg *MyConfig) (m Me) {
 	var buf [8]byte
 	binary.BigEndian.PutUint64(buf[:], m.mask)
 	logrus.Infoln("[me] xor mask", hex.EncodeToString(buf[:]))
-	m.recving = ttl.NewCache[[32]byte, *head.Packet](time.Second * 30)
+	m.recving = ttl.NewCache[uint64, *head.Packet](time.Second * 30)
 	m.recved = ttl.NewCache[uint64, bool](time.Second * 30)
 	return
 }

gold/link/recv.go

@@ -3,8 +3,8 @@ package link
 import (
 	"encoding/binary"
 	"encoding/hex"
+	"hash/crc64"
 	"strconv"
-	"unsafe"
 
 	"github.com/fumiama/WireGold/gold/head"
 	"github.com/sirupsen/logrus"
@@ -26,7 +26,7 @@ func (m *Me) wait(data []byte) *head.Packet {
 		endl = "."
 	}
 	logrus.Debugln("[recv] data bytes", hex.EncodeToString(data[:bound]), endl)
-	data = m.xordec(data)
+	seq, data := m.xordec(data)
 	logrus.Debugln("[recv] data xored", hex.EncodeToString(data[:bound]), endl)
 	flags := head.Flags(data)
 	if !flags.IsValid() {
@@ -34,8 +34,10 @@ func (m *Me) wait(data []byte) *head.Packet {
 		return nil
 	}
 	crc := binary.LittleEndian.Uint64(data[52:head.PacketHeadLen])
-	logrus.Debugf("[recv] packet crc %016x", crc)
-	if m.recved.Get(crc) { // 是重放攻击
+	crclog := crc
+	crc ^= (uint64(seq) << 16)
+	logrus.Debugf("[recv] packet crc %016x, seq %08x, xored crc %016x", crclog, seq, crc)
+	if m.recved.Get(crc) {
 		logrus.Warnln("[recv] ignore duplicated crc packet", strconv.FormatUint(crc, 16))
 		return nil
 	}
@@ -51,17 +53,21 @@ func (m *Me) wait(data []byte) *head.Packet {
 		return h
 	}
 
-	hashd := data[20:52]
-	hsh := *(*[32]byte)(*(*unsafe.Pointer)(unsafe.Pointer(&hashd)))
+	crchash := crc64.New(crc64.MakeTable(crc64.ISO))
+	_, _ = crchash.Write(data[20:52])
+	var buf [4]byte
+	binary.LittleEndian.PutUint32(buf[:], seq)
+	_, _ = crchash.Write(buf[:])
+	hsh := crchash.Sum64()
 	h := m.recving.Get(hsh)
 	if h != nil {
-		logrus.Debugln("[recv] get another frag part of", hex.EncodeToString(hashd))
+		logrus.Debugln("[recv] get another frag part of", strconv.FormatUint(hsh, 16))
 		ok, err := h.Unmarshal(data)
 		if err == nil {
 			if ok {
 				m.recving.Delete(hsh)
 				m.recved.Set(crc, true)
-				logrus.Debugln("[recv] all parts of", hex.EncodeToString(hashd), "has reached")
+				logrus.Debugln("[recv] all parts of", strconv.FormatUint(hsh, 16), "has reached")
 				return h
 			}
 		} else {
@@ -70,7 +76,7 @@ func (m *Me) wait(data []byte) *head.Packet {
 		}
 		return nil
 	}
-	logrus.Debugln("[recv] get new frag part of", hex.EncodeToString(hashd))
+	logrus.Debugln("[recv] get new frag part of", strconv.FormatUint(hsh, 16))
 	h = head.SelectPacket()
 	_, err := h.Unmarshal(data)
 	if err != nil {

gold/link/send.go

@@ -2,6 +2,8 @@ package link
 
 import (
 	"bytes"
+	crand "crypto/rand"
+	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -25,6 +27,9 @@ func (l *Link) WriteAndPut(p *head.Packet, istransfer bool) (n int, err error) {
 	defer p.Put()
 	teatype := l.randkeyidx()
 	sndcnt := uint16(l.incgetsndcnt())
+	var buf [4]byte
+	_, _ = crand.Read(buf[:])
+	seq := binary.BigEndian.Uint32(buf[:])
 	mtu := l.mtu
 	if l.mturandomrange > 0 {
 		mtu -= uint16(rand.Intn(int(l.mturandomrange)))
@@ -40,7 +45,7 @@ func (l *Link) WriteAndPut(p *head.Packet, istransfer bool) (n int, err error) {
 	}
 	remlen := p.BodyLen()
 	if remlen <= delta {
-		return l.write(p, teatype, sndcnt, uint32(remlen), 0, istransfer, false)
+		return l.write(p, teatype, sndcnt, uint32(remlen), 0, istransfer, false, seq)
 	}
 	if istransfer && p.Flags.DontFrag() && remlen > delta {
 		return 0, ErrDropBigDontFragPkt
@@ -53,7 +58,7 @@ func (l *Link) WriteAndPut(p *head.Packet, istransfer bool) (n int, err error) {
 		remlen -= delta
 		logrus.Debugln("[send] split frag [", pos, "~", pos+delta, "], remain:", remlen)
 		packet.CropBody(pos, pos+delta)
-		cnt, err := l.write(packet, teatype, sndcnt, totl, uint16(pos>>3), istransfer, true)
+		cnt, err := l.write(packet, teatype, sndcnt, totl, uint16(pos>>3), istransfer, true, seq)
 		n += cnt
 		if err != nil {
 			return n, err
@@ -66,7 +71,7 @@ func (l *Link) WriteAndPut(p *head.Packet, istransfer bool) (n int, err error) {
 		logrus.Debugln("[send] last frag [", pos, "~", pos+remlen, "]")
 		p.CropBody(pos, pos+remlen)
 		cnt := 0
-		cnt, err = l.write(p, teatype, sndcnt, totl, uint16(pos>>3), istransfer, false)
+		cnt, err = l.write(p, teatype, sndcnt, totl, uint16(pos>>3), istransfer, false, seq)
 		n += cnt
 	}
 	return n, err
@@ -90,7 +95,7 @@ func (l *Link) encrypt(p *head.Packet, sndcnt uint16, teatype uint8) {
 }
 
 // write 向 peer 发包
-func (l *Link) write(p *head.Packet, teatype uint8, additional uint16, datasz uint32, offset uint16, istransfer, hasmore bool) (int, error) {
+func (l *Link) write(p *head.Packet, teatype uint8, additional uint16, datasz uint32, offset uint16, istransfer, hasmore bool, seq uint32) (int, error) {
 	if p.DecreaseAndGetTTL() <= 0 {
 		return 0, ErrTTL
 	}
@@ -98,14 +103,14 @@ func (l *Link) write(p *head.Packet, teatype uint8, additional uint16, datasz ui
 		cpp := p.Copy()
 		_ = time.AfterFunc(time.Millisecond*(10+time.Duration(rand.Intn(40))), func() {
 			defer cpp.Put()
-			_, _ = l.writeonce(cpp, teatype, additional, datasz, offset, istransfer, hasmore)
+			_, _ = l.writeonce(cpp, teatype, additional, datasz, offset, istransfer, hasmore, seq)
 		})
 	}
-	return l.writeonce(p, teatype, additional, datasz, offset, istransfer, hasmore)
+	return l.writeonce(p, teatype, additional, datasz, offset, istransfer, hasmore, seq)
 }
 
 // write 向 peer 发一个包
-func (l *Link) writeonce(p *head.Packet, teatype uint8, additional uint16, datasz uint32, offset uint16, istransfer, hasmore bool) (int, error) {
+func (l *Link) writeonce(p *head.Packet, teatype uint8, additional uint16, datasz uint32, offset uint16, istransfer, hasmore bool, seq uint32) (int, error) {
 	peerep := l.endpoint
 	if peerep == nil {
 		return 0, errors.New("nil endpoint of " + p.Dst.String())
@@ -129,7 +134,7 @@ func (l *Link) writeonce(p *head.Packet, teatype uint8, additional uint16, datas
 	}
 	logrus.Debugln("[send] write", len(d), "bytes data from ep", l.me.conn.LocalAddr(), "to", peerep, "offset:", fmt.Sprintf("%04x", offset))
 	logrus.Debugln("[send] data bytes", hex.EncodeToString(d[:bound]), endl)
-	d = l.me.xorenc(d)
+	d = l.me.xorenc(d, seq)
 	logrus.Debugln("[send] data xored", hex.EncodeToString(d[:bound]), endl)
 	defer helper.PutBytes(d)
 	return l.me.conn.WriteToPeer(d, peerep)