fix: multi-segment hash checking

gold/head/box.go

@@ -17,18 +17,21 @@ import (
 // PreCRC64 calculate crc64 checksum without idxdatsz.
 func (p *Packet) PreCRC64() (crc uint64) {
 	w := bin.SelectWriter()
-	// 固定 TTL 为 0 计算
+	// 固定 TTL 为 0, flag 为空 计算
 	if bin.IsLittleEndian {
 		ttl := p.TTL
+		f := p.Proto
 		p.TTL = 0
+		p.Proto &= protobit
 		w.Write((*[PacketHeadNoCRCLen]byte)(
 			(unsafe.Pointer)(p),
 		)[:])
 		p.TTL = ttl
+		p.Proto = f
 	} else {
 		w.WriteUInt32(p.idxdatsz)
 		w.WriteUInt32(uint32(p.randn))
-		w.WriteUInt16(uint16(p.Proto)) // TTL is set to 0
+		w.WriteUInt16(uint16(p.Proto & protobit)) // TTL, flags is set to 0
 		w.WriteUInt16(p.SrcPort)
 		w.WriteUInt16(p.DstPort)
 		w.WriteUInt16(p.Offset)
@@ -58,9 +61,9 @@ func (p *Packet) WriteHeaderTo(buf *bytes.Buffer) {
 		pbuf.NewBytes(buf.Len()).V(func(b []byte) {
 			copy(b, buf.Bytes())
 			ClearTTL(b)
-			p.md5h8rem = int64(algo.MD5Hash8(b))
+			p.md5h8 = algo.MD5Hash8(b)
 		})
-		_ = binary.Write(buf, binary.LittleEndian, p.md5h8rem)
+		_ = binary.Write(buf, binary.LittleEndian, p.md5h8)
 		return
 	}
 	w := bin.SelectWriter()
@@ -76,10 +79,10 @@ func (p *Packet) WriteHeaderTo(buf *bytes.Buffer) {
 		pbuf.NewBytes(buf.Len()).V(func(b []byte) {
 			copy(b, buf.Bytes())
 			ClearTTL(b)
-			p.md5h8rem = int64(algo.MD5Hash8(b))
+			p.md5h8 = algo.MD5Hash8(b)
 		})
 	})
-	w.WriteUInt64(uint64(p.md5h8rem))
+	w.WriteUInt64(p.md5h8)
 	w.P(func(b *pbuf.Buffer) {
 		_, _ = buf.ReadFrom(b)
 	})

gold/head/builder.go

@@ -69,11 +69,11 @@ func (pb *HeaderBuilder) Dst(ip net.IP, p uint16) *HeaderBuilder {
 func (pb *HeaderBuilder) With(data []byte) *DataBuilder {
 	return (*DataBuilder)(pb.p(func(ub *PacketBuf) {
 		// header crc64 except idxdatasz
-		ub.DAT.md5h8rem = int64(ub.DAT.PreCRC64())
+		ub.DAT.md5h8 = ub.DAT.PreCRC64()
 		// plain data
 		ub.Buffer.Write(data)
 		if config.ShowDebugLog {
-			logrus.Debugln(file.Header(), strconv.FormatUint(uint64(ub.DAT.md5h8rem), 16), "build with data", file.ToLimitHexString(data, 64))
+			logrus.Debugln(file.Header(), strconv.FormatUint(ub.DAT.md5h8, 16), "build with data", file.ToLimitHexString(data, 64))
 		}
 	}))
 }
@@ -89,16 +89,16 @@ func (pb *DataBuilder) Zstd() *DataBuilder {
 		ub.Reset()
 		data.V(func(b []byte) { ub.Write(b) })
 		if config.ShowDebugLog {
-			logrus.Debugln(file.Header(), strconv.FormatUint(uint64(ub.DAT.md5h8rem), 16), "data after zstd", file.ToLimitHexString(ub.Bytes(), 64))
+			logrus.Debugln(file.Header(), strconv.FormatUint(ub.DAT.md5h8, 16), "data after zstd", file.ToLimitHexString(ub.Bytes(), 64))
 		}
 	})
 }
 
 func (pb *DataBuilder) Hash() *DataBuilder {
 	return pb.p(func(ub *PacketBuf) {
-		ub.DAT.hash = algo.Blake2bHash8(
-			uint64(ub.DAT.md5h8rem), ub.Bytes(),
-		)
+		ub.DAT.hashrem = int64(algo.Blake2bHash8(
+			ub.DAT.md5h8, ub.Bytes(),
+		))
 	})
 }
 
@@ -119,7 +119,7 @@ func (pb *DataBuilder) Seal(aead cipher.AEAD, teatyp uint8, additional uint16) *
 		p(func(ub *PacketBuf) {
 			// encrypted data: chacha20(hash + plain)
 			w := bin.SelectWriter()
-			w.WriteUInt64(ub.DAT.hash)
+			w.WriteUInt64(uint64(ub.DAT.hashrem))
 			w.Write(ub.Bytes())
 			w.P(func(b *pbuf.Buffer) {
 				data := algo.EncodeAEAD(aead, additional, b.Bytes())
@@ -133,7 +133,7 @@ func (pb *DataBuilder) Plain(teatyp uint8, additional uint16) *PacketBuilder {
 	return (*PacketBuilder)(pb.tea(teatyp).additional(additional).
 		p(func(ub *PacketBuf) {
 			w := bin.SelectWriter()
-			w.WriteUInt64(ub.DAT.hash)
+			w.WriteUInt64(uint64(ub.DAT.hashrem))
 			w.Write(ub.Bytes())
 			w.P(func(b *pbuf.Buffer) {
 				ub.Reset()

gold/head/packet.go

@@ -3,6 +3,7 @@ package head
 import (
 	"errors"
 	"net"
+	"sync/atomic"
 	"unsafe"
 
 	"github.com/fumiama/orbyte"
@@ -13,8 +14,8 @@ const (
 	// PacketHeadPreCRCIdx skip idxdatsz, which will be set at Seal().
 	PacketHeadPreCRCIdx = unsafe.Offsetof(Packet{}.randn)
 	// PacketHeadNoCRCLen without final crc
-	PacketHeadNoCRCLen = unsafe.Offsetof(Packet{}.md5h8rem)
-	PacketHeadLen      = unsafe.Offsetof(Packet{}.hash)
+	PacketHeadNoCRCLen = unsafe.Offsetof(Packet{}.md5h8)
+	PacketHeadLen      = unsafe.Offsetof(Packet{}.hashrem)
 )
 
 var (
@@ -57,19 +58,18 @@ type Packet struct {
 	src [4]byte
 	// dst 目的 ip (ipv4)
 	dst [4]byte
-	// md5h8rem 发送时记录包头字段除自身外的 checksum 值,
-	// 接收时记录剩余字节数.
+	// md5h8 发送时记录包头字段除自身外的 checksum 值.
 	//
 	// 可以认为在一定时间内唯一 (现已更改算法为 md5 但名字未变)。
-	md5h8rem int64
+	md5h8 uint64
 
 	// 以下字段为包体, 与 data 一起加密
 
-	// hash 使用 BLAKE2B 生成加密前 packet data+crc64 的摘要,
-	// 取其前 8 字节, 小端序读写.
+	// hashrem 使用 BLAKE2B 生成加密前 packet data+crc64 的摘要,
+	// 取其前 8 字节, 小端序读写. 接收时记录剩余字节数.
 	//
 	// https://github.com/fumiama/blake2b-simd
-	hash uint64
+	hashrem int64
 
 	// Buffer 用于 builder with 暂存原始包体数据
 	// 以及接收时保存 body, 通过 PacketBytes 截取偏移.
@@ -92,7 +92,7 @@ func (p *Packet) Size() int {
 
 // CRC64 extract md5h8rem field
 func (p *Packet) CRC64() uint64 {
-	return uint64(p.md5h8rem)
+	return p.md5h8
 }
 
 func (p *Packet) Src() net.IP {
@@ -102,3 +102,7 @@ func (p *Packet) Src() net.IP {
 func (p *Packet) Dst() net.IP {
 	return append(net.IP{}, p.dst[:]...)
 }
+
+func (p *Packet) HasFinished() bool {
+	return atomic.LoadInt64(&p.hashrem) <= 0
+}

gold/head/unbox.go

@@ -37,7 +37,7 @@ func ParsePacketHeader(data []byte) (pbytes PacketBytes, err error) {
 			pb.DAT.Offset = binary.LittleEndian.Uint16(data[14:16])
 			copy(pb.DAT.src[:], data[16:20])
 			copy(pb.DAT.dst[:], data[20:24])
-			pb.DAT.md5h8rem = int64(binary.LittleEndian.Uint64(data[24:32]))
+			pb.DAT.md5h8 = binary.LittleEndian.Uint64(data[24:32])
 		}
 		sz = pb.DAT.Size()
 		if !pb.DAT.Proto.IsValid() {
@@ -60,10 +60,10 @@ func ParsePacketHeader(data []byte) (pbytes PacketBytes, err error) {
 			ClearTTL(b)
 			crc = algo.MD5Hash8(b)
 		})
-		if crc != uint64(pb.DAT.md5h8rem) {
+		if crc != pb.DAT.md5h8 {
 			err = ErrBadCRCChecksum
 			if config.ShowDebugLog {
-				logrus.Warnf("[unbox] exp crc %016x but got %016x", pb.DAT.md5h8rem, crc)
+				logrus.Warnf("[unbox] exp crc %016x but got %016x", pb.DAT.md5h8, crc)
 			}
 			return
 		}
@@ -72,12 +72,12 @@ func ParsePacketHeader(data []byte) (pbytes PacketBytes, err error) {
 		}
 		if sz+int(PacketHeadLen) == len(data) {
 			pb.Buffer.Write(data[PacketHeadLen:])
-			pb.DAT.md5h8rem = -1
+			pb.DAT.hashrem = -1
 			return
 		}
 		pb.Buffer.Grow(sz)
 		pb.Buffer.Write(make([]byte, sz))
-		pb.DAT.md5h8rem = int64(sz)
+		pb.DAT.hashrem = int64(sz)
 	})
 	if err != nil {
 		return
@@ -92,7 +92,7 @@ func ParsePacketHeader(data []byte) (pbytes PacketBytes, err error) {
 //
 // return: complete.
 func (p *Packet) WriteDataSegment(data, buf []byte) bool {
-	if atomic.LoadInt64(&p.md5h8rem) <= 0 {
+	if p.HasFinished() {
 		return true
 	}
 
@@ -103,21 +103,24 @@ func (p *Packet) WriteDataSegment(data, buf []byte) bool {
 	}
 
 	if offset == 0 {
+		p.randn = int32(binary.LittleEndian.Uint32(data[4:8]))
 		p.Proto = flags
+		p.TTL = data[9]
 		p.Offset = 0
+		p.md5h8 = binary.LittleEndian.Uint64(data[24:32])
 		if config.ShowDebugLog {
 			logrus.Debugln("[unbox] parse data set zero offset flags", flags)
 		}
 	}
 
-	rembytes := atomic.LoadInt64(&p.md5h8rem)
+	rembytes := atomic.LoadInt64(&p.hashrem)
 	if rembytes > 0 {
 		n := int64(copy(buf[offset:], data[PacketHeadLen:]))
 		newrem := rembytes - n
-		for !atomic.CompareAndSwapInt64(&p.md5h8rem, rembytes, newrem) {
-			rembytes = atomic.LoadInt64(&p.md5h8rem)
+		for !atomic.CompareAndSwapInt64(&p.hashrem, rembytes, newrem) {
+			rembytes = atomic.LoadInt64(&p.hashrem)
 			newrem = rembytes - n
 		}
 	}
-	return atomic.LoadInt64(&p.md5h8rem) <= 0
+	return p.HasFinished()
 }