Allow nonce difference in specified orders, to prevent unordered packets dropping

[govpn.git] / handshake.go

diff --git a/handshake.go b/handshake.go
index 697e75c50170a7a48a65e5eaf660fce81ffcd3e1..8cac69d8f8954965787a33de0c32b6a95b6e7f74 100644 (file)
--- a/handshake.go
+++ b/handshake.go
@@ -112,7 +112,7 @@ func HandshakeStart(conn *net.UDPConn, addr *net.UDPAddr, key *[32]byte) *Handsh
        return &state
 }
 
-func (h *Handshake) Server(conn *net.UDPConn, key *[32]byte, data []byte) *Peer {
+func (h *Handshake) Server(noncediff uint64, conn *net.UDPConn, key *[32]byte, data []byte) *Peer {
        switch len(data) {
        case 56: // R + ENC(PSK, dh_client_pub) + NULLs
                fmt.Print("[HS1]")
@@ -180,7 +180,11 @@ func (h *Handshake) Server(conn *net.UDPConn, key *[32]byte, data []byte) *Peer
                }
 
                // Switch peer
-               peer := Peer{addr: h.addr, nonceOur: 0, nonceRecv: 0}
+               peer := Peer{
+                       addr: h.addr,
+                       nonceOur: noncediff + 0,
+                       nonceRecv: noncediff + 0,
+               }
                peer.key = KeyFromSecrets(h.sServer[:], decRs[8+8:])
                fmt.Print("[OK]")
                return &peer
@@ -190,7 +194,7 @@ func (h *Handshake) Server(conn *net.UDPConn, key *[32]byte, data []byte) *Peer
        return nil
 }
 
-func (h *Handshake) Client(conn *net.UDPConn, key *[32]byte, data []byte) *Peer {
+func (h *Handshake) Client(noncediff uint64, conn *net.UDPConn, key *[32]byte, data []byte) *Peer {
        switch len(data) {
        case 88: // ENC(PSK, dh_server_pub) + ENC(K, RS + SS) + NULLs
                fmt.Print("[HS2]")
@@ -247,7 +251,11 @@ func (h *Handshake) Client(conn *net.UDPConn, key *[32]byte, data []byte) *Peer
                }
 
                // Switch peer
-               peer := Peer{addr: h.addr, nonceOur: 1, nonceRecv: 0}
+               peer := Peer{
+                       addr: h.addr,
+                       nonceOur: noncediff + 1,
+                       nonceRecv: noncediff + 0,
+               }
                peer.key = KeyFromSecrets(h.sServer[:], h.sClient[:])
                fmt.Print("[OK]")
                return &peer