public SSUHeader(BufRef writer, MessageTypes msgtype)
{
MAC = writer.ReadBufLen(16);
IV = writer.ReadBufLen(16);
IV.Randomize();
FlagBuf = writer.ReadBufLen(1);
MessageType = msgtype;
TimeStampBuf = writer.ReadBufLen(4);
TimeStamp = SSUHost.SSUTime(DateTime.UtcNow);
}
private void SendUnfragmentedSessionConfirmed()
{
var ri = new BufLen(Session.MyRouterContext.MyRouterInfo.ToByteArray());
SendMessage(
SSUHeader.MessageTypes.SessionConfirmed,
Session.MACKey,
Session.SharedKey,
(start, writer) =>
{
writer.Write8((byte)((0 << 4) + 1));
writer.WriteFlip16((ushort)ri.Length);
writer.Write(ri);
Session.SignOnTimeA = BufUtils.Flip32(SSUHost.SSUTime(DateTime.UtcNow));
writer.Write32(Session.SignOnTimeA);
var padding = BufUtils.Get16BytePadding(Session.MyRouterContext.Certificate.SignatureLength + (writer - start));
writer.Write(BufUtils.RandomBytes(padding));
var baddr = new BufLen(Session.RemoteEP.Address.GetAddressBytes());
var bport = BufUtils.Flip16BL((ushort)Session.RemoteEP.Port);
#if LOG_MUCH_TRANSPORT
Logging.LogTransport($"SSU {this}: X for signature {Request.X.Key}.");
Logging.LogTransport($"SSU {this}: Y for signature {Request.Y.Key}.");
Logging.LogTransport($"SSU {this}: Alice address for signature {Request.SCMessage.Address}. Port {Request.SCMessage.Port}.");
Logging.LogTransport($"SSU {this}: Bob address for signature {baddr}. Port {bport}.");
Logging.LogTransport($"SSU {this}: Relay tag {Request.SCMessage.RelayTag}. Signon time {(BufLen)Session.SignOnTimeA}.");
#endif
var sign = I2PSignature.DoSign(Session.MyRouterContext.PrivateSigningKey,
Request.X.Key, Request.Y.Key,
Request.SCMessage.Address, Request.SCMessage.Port,
baddr, bport,
Request.SCMessage.RelayTag, BufUtils.To32BL(Session.SignOnTimeA)
);
writer.Write(sign);
Logging.LogTransport($"SSU {this}: {Session.RemoteEP} " +
$"sending unfragmented SessionConfirmed [0x{writer - start - SSUHeader.FIXED_HEADER_SIZE:X}] bytes.");
return(true);
});
}
private void SendSessionCreated()
{
SendMessage(
SSUHeader.MessageTypes.SessionCreated,
Session.MyRouterContext.IntroKey,
Session.MyRouterContext.IntroKey,
(start, writer) =>
{
writer.Write(Y.Key);
AAddr = Session.RemoteEP.Address.GetAddressBytes();
writer.Write8((byte)AAddr.Length);
writer.Write(AAddr);
APort = BufUtils.Flip16((ushort)Session.RemoteEP.Port);
writer.Write16(APort);
writer.WriteFlip32(RelayTag);
Session.SignOnTimeB = BufUtils.Flip32(SSUHost.SSUTime(DateTime.UtcNow));
writer.Write32(Session.SignOnTimeB);
var sign = I2PSignature.DoSign(Session.MyRouterContext.PrivateSigningKey,
Request.X, Y.Key,
new BufLen(AAddr), BufUtils.To16BL(APort),
Request.Address, BufUtils.Flip16BL((ushort)Session.MyRouterContext.UDPPort),
BufUtils.To32BL(RelayTag), BufUtils.To32BL(Session.SignOnTimeB));
var signstart = new BufLen(writer);
writer.Write(sign);
var padding = BufUtils.Get16BytePadding(writer - signstart);
writer.Write(BufUtils.RandomBytes(padding));
var cipher = new CbcBlockCipher(new AesEngine());
var signcryptbuf = new BufLen(signstart, 0, writer - signstart);
cipher.Init(true, Session.SharedKey.ToParametersWithIV(new BufLen(start, 16, 16)));
cipher.ProcessBytes(signcryptbuf);
return(true);
});
}
private void SendFragmentedSessionConfirmed()
{
var ri = new BufLen(Session.MyRouterContext.MyRouterInfo.ToByteArray());
var rireader = new BufRefLen(ri);
var datafragments = new List <BufLen>();
while (rireader.Length > 0)
{
datafragments.Add(rireader.ReadBufLen(Math.Min(rireader.Length, 472)));
}
for (int i = 0; i < datafragments.Count; ++i)
{
Logging.LogTransport($"SSU {this}: {Session.RemoteEP} " +
$"sending fragment {i + 1} of {datafragments.Count + 1}, [0x{datafragments[i].Length:X}] bytes.");
SendMessage(
SSUHeader.MessageTypes.SessionConfirmed,
Session.MACKey,
Session.SharedKey,
(start, writer) =>
{
writer.Write8((byte)((i << 4) + datafragments.Count + 1));
writer.WriteFlip16((ushort)datafragments[i].Length);
writer.Write(datafragments[i]);
return(true);
});
}
SendMessage(
SSUHeader.MessageTypes.SessionConfirmed,
Session.MACKey,
Session.SharedKey,
(start, writer) =>
{
var frag = datafragments.Count;
writer.Write8((byte)((frag << 4) + frag + 1));
writer.WriteFlip16(0);
Session.SignOnTimeA = BufUtils.Flip32(SSUHost.SSUTime(DateTime.UtcNow));
writer.Write32(Session.SignOnTimeA);
var padding = BufUtils.Get16BytePadding(Session.MyRouterContext.Certificate.SignatureLength + (writer - start));
writer.Write(BufUtils.RandomBytes(padding));
var baddr = new BufLen(Session.RemoteEP.Address.GetAddressBytes());
var sign = I2PSignature.DoSign(Session.MyRouterContext.PrivateSigningKey,
Request.X.Key, Request.Y.Key,
Request.SCMessage.Address, Request.SCMessage.Port,
baddr, BufUtils.Flip16BL((ushort)Session.RemoteEP.Port),
Request.SCMessage.RelayTag, BufUtils.To32BL(Session.SignOnTimeA)
);
writer.Write(sign);
Logging.LogTransport($"SSU {this}: {Session.RemoteEP} " +
$"sending fragment {frag + 1} of {datafragments.Count + 1}, [0x{writer - start - SSUHeader.FIXED_HEADER_SIZE:X}] bytes.");
return(true);
});
}