public static VariableTunnelBuildMessage BuildOutboundTunnel(
TunnelInfo setup,
I2PIdentHash replyaddr, I2PTunnelId replytunnel,
uint replymessageid)
{
byte usehops = (byte)(setup.Hops.Count > 5 ? 8 : 5);
//byte usehops = 7; // 8 makes the response "TunnelBuildReply"
var result = new VariableTunnelBuildMessage(usehops);
// Hop sort order
var requests = new List <BuildRequestRecord>();
for (int i = 0; i < setup.Hops.Count; ++i)
{
// Hop order: Our out dest -> Endpoint
var endpoint = i == setup.Hops.Count - 1;
var gateway = i == 0;
var rec = new BuildRequestRecord();
rec.Data.Randomize();
rec.Flag = 0;
var hop = setup.Hops[i];
rec.OurIdent = hop.Peer.IdentHash;
rec.ReceiveTunnel = hop.TunnelId;
if (!endpoint)
{
var nexthop = setup.Hops[i + 1];
rec.NextIdent = nexthop.Peer.IdentHash;
rec.NextTunnel = nexthop.TunnelId;
}
else
{
rec.SendMessageId = replymessageid;
rec.NextIdent = replyaddr;
rec.NextTunnel = replytunnel;
}
rec.RequestTime = DateTime.UtcNow;
rec.ToAnyone = endpoint;
hop.LayerKey = new I2PSessionKey(rec.LayerKey.Clone());
hop.IVKey = new I2PSessionKey(rec.IVKey.Clone());
requests.Add(rec);
DebugUtils.Log(rec.ToString());
}
// Physical record sort order
var order = new List <AesEGBuildRequestRecord>(result.Records);
order.Shuffle();
// Scramble the rest
for (int i = setup.Hops.Count; i < usehops; ++i)
{
order[i].Data.Randomize();
}
// ElGamal encrypt all of the non random records
// and place them in shuffled order.
for (int i = 0; i < setup.Hops.Count; ++i)
{
var hop = setup.Hops[i];
var egrec = new EGBuildRequestRecord(order[i].Data, requests[i], hop.Peer.IdentHash, hop.Peer.PublicKey);
}
var cipher = new CbcBlockCipher(new AesEngine());
// Dont Aes the first destination
for (int i = setup.Hops.Count - 2; i >= 0; --i)
{
var prevhop = requests[i];
cipher.Init(false, prevhop.ReplyKeyBuf.ToParametersWithIV(prevhop.ReplyIV));
for (int j = i + 1; j < setup.Hops.Count; ++j)
{
cipher.Reset();
cipher.ProcessBytes(order[j].Data);
}
}
for (int i = 0; i < setup.Hops.Count; ++i)
{
setup.Hops[i].ReplyProcessing = new ReplyProcessingInfo()
{
BuildRequestIndex = result.Records.IndexOf(order[i]),
ReplyIV = requests[i].ReplyIV.Clone(),
ReplyKey = new I2PSessionKey(requests[i].ReplyKeyBuf.Clone())
};
}
return(result);
}
public static VariableTunnelBuildMessage BuildInboundTunnel(
TunnelInfo setup)
{
byte usehops = (byte)(setup.Hops.Count > 5 ? 8 : 5);
var result = new VariableTunnelBuildMessage(usehops);
// Hop sort order
var requests = new List <BuildRequestRecord>();
for (int i = 0; i < setup.Hops.Count; ++i)
{
// Hop order: GW -> us
var endpoint = i == setup.Hops.Count - 1;
var gateway = i == 0;
var rec = new BuildRequestRecord();
rec.Data.Randomize();
rec.Flag = 0;
var hop = setup.Hops[i];
rec.OurIdent = hop.Peer.IdentHash;
rec.ReceiveTunnel = hop.TunnelId;
if (!endpoint)
{
var nexthop = setup.Hops[i + 1];
rec.NextIdent = nexthop.Peer.IdentHash;
rec.NextTunnel = nexthop.TunnelId;
}
else
{
// Used to identify the record as the last in an inbound tunnel to us
rec.NextIdent = hop.Peer.IdentHash;
rec.NextTunnel = hop.TunnelId;
}
rec.RequestTime = DateTime.UtcNow;
rec.FromAnyone = gateway;
hop.LayerKey = new I2PSessionKey(rec.LayerKey.Clone());
hop.IVKey = new I2PSessionKey(rec.IVKey.Clone());
requests.Add(rec);
DebugUtils.Log(rec.ToString());
}
// Physical record sort order
var order = new List <AesEGBuildRequestRecord>(result.Records);
order.Shuffle();
// Scramble the rest
for (int i = setup.Hops.Count; i < usehops; ++i)
{
order[i].Data.Randomize();
}
// ElGamal encrypt all of the non random records
// and place them in shuffled order.
for (int i = 0; i < setup.Hops.Count; ++i)
{
var hop = setup.Hops[i];
var egrec = new EGBuildRequestRecord(order[i].Data, requests[i], hop.Peer.IdentHash, hop.Peer.PublicKey);
}
var cipher = new BufferedBlockCipher(new CbcBlockCipher(new AesEngine()));
// Dont Aes the first block
for (int i = setup.Hops.Count - 2; i >= 0; --i)
{
var prevhop = requests[i];
cipher.Init(false, new ParametersWithIV(new KeyParameter(prevhop.ReplyKey.ToByteArray()), prevhop.ReplyIV.ToByteArray()));
for (int j = i + 1; j < setup.Hops.Count; ++j)
{
cipher.Reset();
order[j].Process(cipher);
}
}
for (int i = 0; i < setup.Hops.Count; ++i)
{
setup.Hops[i].ReplyProcessing = new ReplyProcessingInfo()
{
BuildRequestIndex = result.Records.IndexOf(order[i]),
ReplyIV = requests[i].ReplyIV.Clone(),
ReplyKey = new I2PSessionKey(requests[i].ReplyKeyBuf.Clone())
};
}
return(result);
}