wire-mix: hardcode msize, use [][20]byte for MixVect type

wire/common.go

@@ -487,6 +487,14 @@ func writeElement(w io.Writer, element interface{}) error {
 		}
 		return nil
 
+	// Mixed message
+	case [MixMsgSize]byte:
+		_, err := w.Write(e[:])
+		if err != nil {
+			return err
+		}
+		return nil
+
 	case *[32]byte:
 		_, err := w.Write(e[:])
 		if err != nil {

wire/message_test.go

@@ -87,7 +87,7 @@ func TestMessage(t *testing.T) {
 	msgMixKE := NewMsgMixKeyExchange([33]byte{}, [32]byte{}, 1, 1, [33]byte{}, [1218]byte{}, [32]byte{}, []chainhash.Hash{})
 	msgMixCT := NewMsgMixCiphertexts([33]byte{}, [32]byte{}, 1, 1, [][1047]byte{}, []chainhash.Hash{})
 	msgMixSR := NewMsgMixSlotReserve([33]byte{}, [32]byte{}, 1, 1, [][][]byte{{{}}}, []chainhash.Hash{})
-	msgMixDC := NewMsgMixDCNet([33]byte{}, [32]byte{}, 1, 1, []MixVect{*NewMixVect(1, 1)}, []chainhash.Hash{})
+	msgMixDC := NewMsgMixDCNet([33]byte{}, [32]byte{}, 1, 1, []MixVect{make(MixVect, 1)}, []chainhash.Hash{})
 	msgMixCM := NewMsgMixConfirm([33]byte{}, [32]byte{}, 1, 1, NewMsgTx(), []chainhash.Hash{})
 	msgMixRS := NewMsgMixSecrets([33]byte{}, [32]byte{}, 1, 1, [32]byte{}, [][]byte{}, [][]byte{})
 
@@ -126,7 +126,7 @@ func TestMessage(t *testing.T) {
 		{msgMixKE, msgMixKE, pver, MainNet, 1449},
 		{msgMixCT, msgMixCT, pver, MainNet, 166},
 		{msgMixSR, msgMixSR, pver, MainNet, 169},
-		{msgMixDC, msgMixDC, pver, MainNet, 171},
+		{msgMixDC, msgMixDC, pver, MainNet, 189},
 		{msgMixCM, msgMixCM, pver, MainNet, 181},
 		{msgMixRS, msgMixRS, pver, MainNet, 213},
 	}

wire/mixvect.go

@@ -9,36 +9,20 @@ import (
 	"strings"
 )
 
-// MixVect is a N-element vector of Msize []byte messages.
-type MixVect struct {
-	N     uint32
-	Msize uint32
-	Data  []byte
-}
+const MixMsgSize = 20
 
-// NewMixVect returns a zero vector for holding n messages of msize length.
-func NewMixVect(n, msize uint32) *MixVect {
-	return &MixVect{
-		N:     n,
-		Msize: msize,
-		Data:  make([]byte, n*msize),
-	}
-}
-
-func (v *MixVect) String() string {
-	m := func(i int) []byte {
-		off := uint32(i) * v.Msize
-		return v.Data[off : off+v.Msize]
-	}
+// MixVect is vector of padded or unpadded DC-net messages.
+type MixVect [][MixMsgSize]byte
 
+func (v MixVect) String() string {
 	b := new(strings.Builder)
-	b.Grow(2 + int(v.N*(2*v.Msize+1)))
+	b.Grow(2 + len(v)*(2*MixMsgSize+1))
 	b.WriteString("[")
-	for i := 0; uint32(i) < v.N; i++ {
+	for i := range v {
 		if i != 0 {
 			b.WriteString(" ")
 		}
-		fmt.Fprintf(b, "%x", m(i))
+		fmt.Fprintf(b, "%x", v[i][:])
 	}
 	b.WriteString("]")
 	return b.String()

wire/msgmixdcnet.go

@@ -139,7 +139,7 @@ func (msg *MsgMixDCNet) writeMessageNoSignature(op string, w io.Writer, pver uin
 	}
 
 	for i := range msg.DCNet {
-		err := writeMixVect(w, pver, &msg.DCNet[i])
+		err := writeMixVect(w, pver, msg.DCNet[i])
 		if err != nil {
 			return err
 		}
@@ -166,18 +166,21 @@ func (msg *MsgMixDCNet) writeMessageNoSignature(op string, w io.Writer, pver uin
 	return nil
 }
 
-func writeMixVect(w io.Writer, pver uint32, vec *MixVect) error {
-	err := WriteVarInt(w, pver, uint64(vec.N))
+func writeMixVect(w io.Writer, pver uint32, vec MixVect) error {
+	err := WriteVarInt(w, pver, uint64(len(vec)))
 	if err != nil {
 		return err
 	}
-	err = WriteVarInt(w, pver, uint64(vec.Msize))
+	err = WriteVarInt(w, pver, MixMsgSize)
 	if err != nil {
 		return err
 	}
-	err = WriteVarBytes(w, pver, vec.Data)
-	if err != nil {
-		return err
+
+	for i := range vec {
+		_, err = w.Write(vec[i][:])
+		if err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -196,23 +199,19 @@ func readMixVect(op string, r io.Reader, pver uint32, vec *MixVect) error {
 	if err != nil {
 		return err
 	}
-	if msize > 32 {
-		msg := "mixed message length exceeds max"
+	if msize != MixMsgSize {
+		msg := fmt.Sprintf("mixed message length must be %d [got: %d]",
+			MixMsgSize, msize)
 		return messageError(op, ErrInvalidMsg, msg)
 	}
-	data, err := ReadVarBytes(r, pver, MaxMixKPCount*32, "Data")
-	if err != nil {
-		return err
-	}
-	if int(n*msize) != len(data) {
-		msg := "vec dimensions do not match data length"
-		return messageError(op, ErrInvalidMsg, msg)
+	*vec = make(MixVect, n)
+	for i := uint64(0); i < n; i++ {
+		_, err = r.Read((*vec)[i][:])
+		if err != nil {
+			return err
+		}
 	}
 
-	vec.N = uint32(n)
-	vec.Msize = uint32(msize)
-	vec.Data = data
-
 	return nil
 }
 

wire/msgmixdcnet_test.go

@@ -45,10 +45,9 @@ func TestMixDCWire(t *testing.T) {
 	// dcnet, ranging from 0x85 through 0x94
 	b := byte(0x85)
 	for i := 0; i < mcount; i++ {
-		dcnet[i].N = kpcount
-		dcnet[i].Msize = 32
+		dcnet[i] = make(MixVect, kpcount)
 		for j := 0; j < int(kpcount); j++ {
-			dcnet[i].Data = append(dcnet[i].Data, repeat(b, 32)...)
+			copy(dcnet[i][j][:], repeat(b, 32))
 			b++
 		}
 	}