internal static LowLevelUdpResponseScanner GetScanner(DirectChannelToken32 localDirectChannelToken32, InviteSession session)
{
if (!session.DerivedDirectChannelSharedDhSecretsAE)
{
throw new InvalidOperationException("DerivedDirectChannelSharedDhSecretsAE=false");
}
BinaryProcedures.CreateBinaryWriter(out var ms, out var w);
w.Write((byte)PacketTypes.MessageStart);
localDirectChannelToken32.Encode(w);
return(new LowLevelUdpResponseScanner
{
ResponseFirstBytes = ms.ToArray(),
OptionalFilter = (udpData) =>
{
if (!session.DerivedDirectChannelSharedDhSecretsAE)
{
return false;
}
var msgStart = Decode(udpData);
if (msgStart.MessageHMAC.Equals(
session.GetMessageHMAC(w2 => msgStart.GetSignedFieldsForMessageHMAC(w2, true))
) == false)
{
return false;
}
return true;
}
});
}
public static LowLevelUdpResponseScanner GetScanner(DirectChannelToken32 senderToken32, uint pingRequestId32, InviteSession session)
{
BinaryProcedures.CreateBinaryWriter(out var ms, out var w);
GetHeaderFields(w, senderToken32, pingRequestId32);
return(new LowLevelUdpResponseScanner
{
ResponseFirstBytes = ms.ToArray(),
OptionalFilter = (udpData) =>
{
var pong = Decode(udpData);
if (pong.PingPongHMAC.Equals(
session.GetPingPongHMAC(pong.GetSignedFieldsForPingPongHMAC)
) == false)
{
return false;
}
return true;
}
});
}
static void GetHeaderFields(BinaryWriter writer, DirectChannelToken32 directChannelToken32, uint pingRequestId32)
{
writer.Write((byte)PacketTypes.DmpPong);
directChannelToken32.Encode(writer);
writer.Write(pingRequestId32);
}