internal void OnReceivedDmpPing(IPEndPoint remoteEndpoint, byte[] udpData) // engine thread
{
WriteToLog_detail($">> OnReceivedDmpPing(remoteEndpoint={remoteEndpoint})");
if (!remoteEndpoint.Equals(RemoteSessionDescription.DirectChannelEndPoint))
{
throw new PossibleAttackException();
}
if (SharedPingPongHmacKey == null)
{
WriteToLog_detail($"ignoring received DMP PING: SharedPingPongHmacKey is not initialized yet");
return;
}
var ping = DmpPingPacket.DecodeAndVerify(udpData, this);
var pong = new DmpPongPacket
{
DirectChannelToken32 = RemoteSessionDescription.DirectChannelToken32,
PingRequestId32 = ping.PingRequestId32,
};
if (ping.PublicEcdheKey != null)
{
pong.PublicEcdheKey = new EcdhPublicKey {
Ecdh25519PublicKey = this.LocalDirectChannelEcdhePublicKey
};
this.DeriveDirectChannelSharedDhSecret(ping.PublicEcdheKey.Ecdh25519PublicKey);
}
pong.PingPongHMAC = GetPingPongHMAC(pong.GetSignedFieldsForPingPongHMAC);
var pongUdpData = pong.Encode();
_localDrpPeer.Engine.SendPacket(pongUdpData, remoteEndpoint);
}
internal void OnReceivedDmpPing(IPEndPoint remoteEndpoint, byte[] udpData) // engine thread
{
WriteToLog_detail($">> OnReceivedDmpPing(remoteEndpoint={remoteEndpoint})");
if (!remoteEndpoint.Address.Equals(RemoteSessionDescription.DirectChannelEndPoint.Address))
{
throw new PossibleAttackException($"receibed DMP PING from bad IP address {remoteEndpoint.Address}, expected from {RemoteSessionDescription.DirectChannelEndPoint.Address}");
}
if (SharedPingPongHmacKey == null)
{
WriteToLog_detail($"ignoring received DMP PING: SharedPingPongHmacKey is not initialized yet");
return;
}
var ping = DmpPingPacket.DecodeAndVerify(udpData, this);
if (this.RemoteSessionDescription.DirectChannelEndPoint.Port != remoteEndpoint.Port)
{
WriteToLog_detail($"updating remote peer DirectChannel port from {this.RemoteSessionDescription.DirectChannelEndPoint} to {remoteEndpoint} (when remote peer opens another port in NAT)");
this.RemoteSessionDescription.DirectChannelEndPoint = remoteEndpoint;
if (this.InitialPendingPingRequest != null)
{
this.InitialPendingPingRequest.ResponderEndpoint = remoteEndpoint;
}
}
var pong = new DmpPongPacket
{
DirectChannelToken32 = RemoteSessionDescription.DirectChannelToken32,
PingRequestId32 = ping.PingRequestId32,
};
if (ping.PublicEcdheKey != null)
{
pong.PublicEcdheKey = new EcdhPublicKey {
Ecdh25519PublicKey = this.LocalDirectChannelEcdhePublicKey
};
this.DeriveDirectChannelSharedDhSecret(ping.PublicEcdheKey.Ecdh25519PublicKey);
}
pong.PingPongHMAC = GetPingPongHMAC(pong.GetSignedFieldsForPingPongHMAC);
var pongUdpData = pong.Encode();
_localDrpPeer.Engine.SendPacket(pongUdpData, remoteEndpoint);
}