public static InviteRequestPacket Decode_VerifyNeighborHMAC(byte[] udpData, ConnectionToNeighbor receivedFromNeighbor)
{
var r = new InviteRequestPacket();
r.DecodedUdpPayloadData = udpData;
var reader = PacketProcedures.CreateBinaryReader(udpData, 1);
var flags = reader.ReadByte();
if ((flags & FlagsMask_MustBeZero) != 0)
{
throw new NotImplementedException();
}
r.NeighborToken32 = NeighborToken32.Decode(reader);
if (receivedFromNeighbor.LocalNeighborToken32.Equals(r.NeighborToken32) == false)
{
throw new UnmatchedFieldsException();
}
r.ReqTimestamp32S = reader.ReadUInt32();
r.RequesterRegistrationId = RegistrationId.Decode(reader);
r.ResponderRegistrationId = RegistrationId.Decode(reader);
r.RequesterEcdhePublicKey = EcdhPublicKey.Decode(reader);
r.RequesterRegistrationSignature = RegistrationSignature.Decode(reader);
r.NumberOfHopsRemaining = reader.ReadByte();
r.ReqP2pSeq16 = RequestP2pSequenceNumber16.Decode(reader);
r.NeighborHMAC = HMAC.Decode(reader);
if (r.NeighborHMAC.Equals(receivedFromNeighbor.GetNeighborHMAC(r.GetSignedFieldsForNeighborHMAC)) == false)
{
throw new BadSignatureException("invalid INVITE REQ NeighborHMAC 5902");
}
return(r);
}
/// <summary>
/// creates a scanner that finds CFM that matches to REQ
/// the scanner will verify CFM.NeighborHMAC
/// </summary>
/// <param name="connectionToNeighbor">
/// peer that responds with CFM
/// </param>
public static LowLevelUdpResponseScanner GetScanner(Logger logger, InviteRequestPacket req, ConnectionToNeighbor connectionToNeighbor)
{
PacketProcedures.CreateBinaryWriter(out var ms, out var w);
w.Write((byte)PacketTypes.InviteCfm);
w.Write((byte)0); // flags
connectionToNeighbor.LocalNeighborToken32.Encode(w);
w.Write(req.ReqTimestamp32S);
req.RequesterRegistrationId.Encode(w);
req.ResponderRegistrationId.Encode(w);
var r = new LowLevelUdpResponseScanner
{
ResponseFirstBytes = ms.ToArray(),
IgnoredByteAtOffset1 = 1 // ignore flags
};
r.OptionalFilter = (responseData) =>
{
if (connectionToNeighbor.IsDisposed)
{
logger.WriteToLog_needsAttention("ignoring CFM: connection is disposed");
return(false);
}
var cfm = Decode(responseData);
if (cfm.NeighborHMAC.Equals(connectionToNeighbor.GetNeighborHMAC(cfm.GetSignedFieldsForNeighborHMAC)) == false)
{
logger.WriteToLog_attacks("ignoring CFM: received NeighborHMAC is invalid");
return(false);
}
return(true);
};
return(r);
}