Old magic numbers knowledge

[nncp.git] / src / pkt.go

diff --git a/src/pkt.go b/src/pkt.go
index 3aed5a64c30674d7ad1c3e1b24377604325442c1..135e850950e688c087abfe4ce0fb1ae6987fe63f 100644 (file)
--- a/src/pkt.go
+++ b/src/pkt.go
@@ -53,10 +53,8 @@ const (
 )
 
 var (
-       MagicNNCPPv3 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 3}
-       MagicNNCPEv5 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 5}
-       BadMagic     error   = errors.New("Unknown magic number")
-       BadPktType   error   = errors.New("Unknown packet type")
+       BadMagic   error = errors.New("Unknown magic number")
+       BadPktType error = errors.New("Unknown packet type")
 
        PktOverhead    int64
        PktEncOverhead int64
@@ -102,7 +100,7 @@ func init() {
                panic(err)
        }
        pktEnc := PktEnc{
-               Magic:     MagicNNCPEv5,
+               Magic:     MagicNNCPEv5.B,
                Sender:    dummyId,
                Recipient: dummyId,
        }
@@ -118,7 +116,7 @@ func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
                return nil, errors.New("Too long path")
        }
        pkt := Pkt{
-               Magic:   MagicNNCPPv3,
+               Magic:   MagicNNCPPv3.B,
                Type:    typ,
                Nice:    nice,
                PathLen: uint8(len(path)),
@@ -209,7 +207,7 @@ func PktEncWrite(
                return nil, err
        }
        tbs := PktTbs{
-               Magic:     MagicNNCPEv5,
+               Magic:     MagicNNCPEv5.B,
                Nice:      nice,
                Sender:    our.Id,
                Recipient: their.Id,
@@ -222,7 +220,7 @@ func PktEncWrite(
        signature := new([ed25519.SignatureSize]byte)
        copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
        pktEnc := PktEnc{
-               Magic:     MagicNNCPEv5,
+               Magic:     MagicNNCPEv5.B,
                Nice:      nice,
                Sender:    our.Id,
                Recipient: their.Id,
@@ -242,7 +240,7 @@ func PktEncWrite(
        curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
 
        key := make([]byte, chacha20poly1305.KeySize)
-       blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
+       blake3.DeriveKey(key, string(MagicNNCPEv5.B[:]), sharedKey[:])
        aead, err := chacha20poly1305.New(key)
        if err != nil {
                return nil, err
@@ -266,7 +264,7 @@ func PktEncWrite(
                return nil, io.ErrUnexpectedEOF
        }
        if padSize > 0 {
-               blake3.DeriveKey(key, string(MagicNNCPEv5[:])+" PAD", sharedKey[:])
+               blake3.DeriveKey(key, string(MagicNNCPEv5.B[:])+" PAD", sharedKey[:])
                xof := blake3.New(32, key).XOF()
                if _, err = io.CopyN(out, xof, padSize); err != nil {
                        return nil, err
@@ -277,7 +275,7 @@ func PktEncWrite(
 
 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) ([]byte, bool, error) {
        tbs := PktTbs{
-               Magic:     MagicNNCPEv5,
+               Magic:     MagicNNCPEv5.B,
                Nice:      pktEnc.Nice,
                Sender:    their.Id,
                Recipient: our.Id,
@@ -301,8 +299,21 @@ func PktEncRead(
        if err != nil {
                return nil, 0, err
        }
-       if pktEnc.Magic != MagicNNCPEv5 {
-               return nil, 0, BadMagic
+       switch pktEnc.Magic {
+       case MagicNNCPEv1.B:
+               err = MagicNNCPEv1.TooOld()
+       case MagicNNCPEv2.B:
+               err = MagicNNCPEv2.TooOld()
+       case MagicNNCPEv3.B:
+               err = MagicNNCPEv3.TooOld()
+       case MagicNNCPEv4.B:
+               err = MagicNNCPEv4.TooOld()
+       case MagicNNCPEv5.B:
+       default:
+               err = BadMagic
+       }
+       if err != nil {
+               return nil, 0, err
        }
        their, known := nodes[*pktEnc.Sender]
        if !known {
@@ -323,7 +334,7 @@ func PktEncRead(
        curve25519.ScalarMult(sharedKey, our.ExchPrv, &pktEnc.ExchPub)
 
        key := make([]byte, chacha20poly1305.KeySize)
-       blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
+       blake3.DeriveKey(key, string(MagicNNCPEv5.B[:]), sharedKey[:])
        aead, err := chacha20poly1305.New(key)
        if err != nil {
                return their, 0, err