Add time synchronization requirement option

[govpn.git] / src / cypherpunks.ru / govpn / handshake.go

diff --git a/src/cypherpunks.ru/govpn/handshake.go b/src/cypherpunks.ru/govpn/handshake.go
index d9e86352dbde5e26b6a22d40e66859b8908d7e6d..4f080eb34647c1494c3b78f6b2e9bdabf082177f 100644 (file)
--- a/src/cypherpunks.ru/govpn/handshake.go
+++ b/src/cypherpunks.ru/govpn/handshake.go
@@ -133,13 +133,15 @@ func NewHandshake(addr string, conn io.Writer, conf *PeerConf) *Handshake {
 }
 
 // Generate ID tag from client identification and data.
-func idTag(id *PeerId, data []byte) []byte {
+func idTag(id *PeerId, timeSync int, data []byte) []byte {
        ciph, err := xtea.NewCipher(id[:])
        if err != nil {
                panic(err)
        }
        enc := make([]byte, xtea.BlockSize)
-       ciph.Encrypt(enc, data[:xtea.BlockSize])
+       copy(enc, data)
+       AddTimeSync(timeSync, enc)
+       ciph.Encrypt(enc, enc)
        return enc
 }
 
@@ -172,7 +174,7 @@ func HandshakeStart(addr string, conn io.Writer, conf *PeerConf) *Handshake {
                salsa20.XORKeyStream(enc, enc, state.rNonce[:], state.dsaPubH)
        }
        data := append(state.rNonce[:], enc...)
-       data = append(data, idTag(state.Conf.Id, state.rNonce[:])...)
+       data = append(data, idTag(state.Conf.Id, state.Conf.TimeSync, state.rNonce[:])...)
        state.conn.Write(data)
        return state
 }
@@ -262,7 +264,9 @@ func (h *Handshake) Server(data []byte) *Peer {
                }
 
                // Send that to client
-               h.conn.Write(append(encPub, append(encRs, idTag(h.Conf.Id, encPub)...)...))
+               h.conn.Write(append(encPub, append(
+                       encRs, idTag(h.Conf.Id, h.Conf.TimeSync, encPub)...,
+               )...))
                h.LastPing = time.Now()
        } else
        // ENC(K, R+1, RS + RC + SC + Sign(DSAPriv, K)) + IDtag
@@ -317,7 +321,7 @@ func (h *Handshake) Server(data []byte) *Peer {
                } else {
                        salsa20.XORKeyStream(enc, enc, h.rNonceNext(2), h.key)
                }
-               h.conn.Write(append(enc, idTag(h.Conf.Id, enc)...))
+               h.conn.Write(append(enc, idTag(h.Conf.Id, h.Conf.TimeSync, enc)...))
 
                // Switch peer
                peer := newPeer(
@@ -431,7 +435,7 @@ func (h *Handshake) Client(data []byte) *Peer {
                }
 
                // Send that to server
-               h.conn.Write(append(enc, idTag(h.Conf.Id, enc)...))
+               h.conn.Write(append(enc, idTag(h.Conf.Id, h.Conf.TimeSync, enc)...))
                h.LastPing = time.Now()
        } else
        // ENC(K, R+2, RC) + IDtag