mirror of
https://github.com/PurpleI2P/i2pd
synced 2024-11-10 08:00:38 +03:00
858 lines
26 KiB
C++
858 lines
26 KiB
C++
#include <string.h>
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#include <boost/bind.hpp>
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#include <cryptopp/dh.h>
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#include <cryptopp/secblock.h>
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#include "CryptoConst.h"
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#include "Log.h"
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#include "Timestamp.h"
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#include "RouterContext.h"
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#include "hmac.h"
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#include "SSU.h"
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namespace i2p
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{
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namespace ssu
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{
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SSUSession::SSUSession (SSUServer * server, boost::asio::ip::udp::endpoint& remoteEndpoint,
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const i2p::data::RouterInfo * router): m_Server (server), m_RemoteEndpoint (remoteEndpoint),
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m_RemoteRouter (router), m_State (eSessionStateUnknown)
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{
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}
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void SSUSession::CreateAESandMacKey (uint8_t * pubKey, uint8_t * aesKey, uint8_t * macKey)
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{
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CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
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CryptoPP::SecByteBlock secretKey(dh.AgreedValueLength());
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if (!dh.Agree (secretKey, i2p::context.GetPrivateKey (), pubKey))
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{
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LogPrint ("Couldn't create shared key");
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return;
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};
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if (secretKey[0] & 0x80)
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{
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aesKey[0] = 0;
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memcpy (aesKey + 1, secretKey, 31);
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memcpy (macKey, secretKey + 31, 32);
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}
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else
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{
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memcpy (aesKey, secretKey, 32);
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memcpy (macKey, secretKey + 32, 32);
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}
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}
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void SSUSession::ProcessNextMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
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{
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switch (m_State)
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{
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case eSessionStateConfirmedSent:
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case eSessionStateEstablished:
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// most common case
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ProcessMessage (buf, len);
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break;
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// establishing
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case eSessionStateUnknown:
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// session request
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ProcessSessionRequest (buf, len, senderEndpoint);
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break;
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case eSessionStateRequestSent:
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// session created
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ProcessSessionCreated (buf, len);
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break;
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case eSessionStateCreatedSent:
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// session confirmed
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ProcessSessionConfirmed (buf, len);
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break;
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case eSessionRelayRequestSent:
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// relay response
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ProcessRelayResponse (buf,len);
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break;
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case eSessionRelayRequestReceived:
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// HolePunch
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m_State = eSessionStateUnknown;
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Connect ();
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break;
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default:
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LogPrint ("SSU state not implemented yet");
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}
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}
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void SSUSession::ProcessMessage (uint8_t * buf, size_t len)
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{
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if (Validate (buf, len, m_MacKey))
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{
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Decrypt (buf, len, m_SessionKey);
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SSUHeader * header = (SSUHeader *)buf;
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uint8_t payloadType = header->flag >> 4;
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switch (payloadType)
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{
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case PAYLOAD_TYPE_DATA:
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LogPrint ("SSU data received");
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ProcessData (buf + sizeof (SSUHeader), len - sizeof (SSUHeader));
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break;
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case PAYLOAD_TYPE_TEST:
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LogPrint ("SSU test received");
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break;
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case PAYLOAD_TYPE_SESSION_DESTROYED:
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{
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LogPrint ("SSU session destroy received");
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if (m_Server)
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m_Server->DeleteSession (this); // delete this
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break;
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}
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case PAYLOAD_TYPE_RELAY_INTRO:
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LogPrint ("SSU relay intro received");
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// TODO:
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break;
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default:
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LogPrint ("Unexpected SSU payload type ", (int)payloadType);
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}
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}
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else
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{
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LogPrint ("MAC key failed. Trying intro key");
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auto introKey = GetIntroKey ();
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if (introKey && Validate (buf, len, introKey))
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{
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Decrypt (buf, len, introKey);
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SSUHeader * header = (SSUHeader *)buf;
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LogPrint ("Unexpected SSU payload type ", (int)(header->flag >> 4));
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// TODO:
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}
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else
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LogPrint ("MAC verifcation failed");
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m_State = eSessionStateUnknown;
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}
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}
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void SSUSession::ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
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{
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LogPrint ("Process session request");
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// use our intro key
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if (ProcessIntroKeyEncryptedMessage (PAYLOAD_TYPE_SESSION_REQUEST, buf, len))
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{
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m_State = eSessionStateRequestReceived;
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LogPrint ("Session request received");
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m_RemoteEndpoint = senderEndpoint;
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SendSessionCreated (buf + sizeof (SSUHeader));
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}
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}
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void SSUSession::ProcessSessionCreated (uint8_t * buf, size_t len)
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{
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LogPrint ("Process session created");
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if (!m_RemoteRouter)
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{
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LogPrint ("Unsolicited session created message");
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return;
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}
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// use remote intro key
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if (ProcessIntroKeyEncryptedMessage (PAYLOAD_TYPE_SESSION_CREATED, buf, len))
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{
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m_State = eSessionStateCreatedReceived;
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LogPrint ("Session created received");
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uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, signed on time
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uint8_t * payload = buf + sizeof (SSUHeader);
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uint8_t * y = payload;
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memcpy (signedData, i2p::context.GetRouterIdentity ().publicKey, 256); // x
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memcpy (signedData + 256, y, 256); // y
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payload += 256;
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payload += 1; // size, assume 4
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uint8_t * ourAddress = payload;
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boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )ourAddress));
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payload += 4; // address
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uint16_t ourPort = be16toh (*(uint16_t *)payload);
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payload += 2; // port
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memcpy (signedData + 512, ourAddress, 6); // our IP and port
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LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
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i2p::context.UpdateAddress (ourIP.to_string ().c_str ());
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*(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP
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*(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port
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memcpy (signedData + 524, payload, 8); // relayTag and signed on time
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uint32_t relayTag = be32toh (*(uint32_t *)payload);
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payload += 4; // relayTag
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payload += 4; // signed on time
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// decrypt DSA signature
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m_Decryption.SetKeyWithIV (m_SessionKey, 32, ((SSUHeader *)buf)->iv);
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m_Decryption.ProcessData (payload, payload, 48);
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// verify
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CryptoPP::DSA::PublicKey pubKey;
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pubKey.Initialize (i2p::crypto::dsap, i2p::crypto::dsaq, i2p::crypto::dsag, CryptoPP::Integer (m_RemoteRouter->GetRouterIdentity ().signingKey, 128));
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CryptoPP::DSA::Verifier verifier (pubKey);
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if (!verifier.VerifyMessage (signedData, 532, payload, 40))
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LogPrint ("SSU signature verification failed");
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SendSessionConfirmed (y, ourAddress, relayTag);
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}
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}
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void SSUSession::ProcessSessionConfirmed (uint8_t * buf, size_t len)
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{
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LogPrint ("Process session confirmed");
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if (Validate (buf, len, m_MacKey))
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{
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Decrypt (buf, len, m_SessionKey);
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SSUHeader * header = (SSUHeader *)buf;
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if ((header->flag >> 4) == PAYLOAD_TYPE_SESSION_CONFIRMED)
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{
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m_State = eSessionStateConfirmedReceived;
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LogPrint ("Session confirmed received");
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m_State = eSessionStateEstablished;
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SendI2NPMessage (CreateDeliveryStatusMsg (0));
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Established ();
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}
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else
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LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));
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}
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else
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LogPrint ("MAC verifcation failed");
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}
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void SSUSession::SendSessionRequest ()
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{
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auto introKey = GetIntroKey ();
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if (!introKey)
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{
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LogPrint ("SSU is not supported");
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return;
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}
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uint8_t buf[304 + 18]; // 304 bytes for ipv4 (320 for ipv6)
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uint8_t * payload = buf + sizeof (SSUHeader);
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memcpy (payload, i2p::context.GetRouterIdentity ().publicKey, 256);
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payload[256] = 4; // we assume ipv4
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*(uint32_t *)(payload + 257) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ());
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uint8_t iv[16];
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CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
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rnd.GenerateBlock (iv, 16); // random iv
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FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_REQUEST, buf, 304, introKey, iv, introKey);
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m_State = eSessionStateRequestSent;
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m_Server->Send (buf, 304, m_RemoteEndpoint);
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}
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void SSUSession::SendRelayRequest (const i2p::data::RouterInfo::Introducer& introducer)
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{
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auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
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if (!address)
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{
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LogPrint ("SSU is not supported");
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return;
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}
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uint8_t buf[96 + 18];
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uint8_t * payload = buf + sizeof (SSUHeader);
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*(uint32_t *)payload = htobe32 (introducer.iTag);
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payload += 4;
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*payload = 0; // no address
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payload++;
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*(uint16_t *)payload = 0; // port = 0
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payload += 2;
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*payload = 0; // challenge
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payload++;
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memcpy (payload, address->key, 32);
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payload += 32;
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CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
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*(uint32_t *)payload = htobe32 (rnd.GenerateWord32 ()); // nonce
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uint8_t iv[16];
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rnd.GenerateBlock (iv, 16); // random iv
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FillHeaderAndEncrypt (PAYLOAD_TYPE_RELAY_REQUEST, buf, 96, introducer.iKey, iv, introducer.iKey);
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m_State = eSessionRelayRequestSent;
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m_Server->Send (buf, 96, m_RemoteEndpoint);
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}
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void SSUSession::SendSessionCreated (const uint8_t * x)
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{
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auto introKey = GetIntroKey ();
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auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
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if (!introKey || !address)
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{
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LogPrint ("SSU is not supported");
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return;
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}
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uint8_t signedData[532]; // x,y, remote IP, remote port, our IP, our port, relayTag, signed on time
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memcpy (signedData, x, 256); // x
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uint8_t buf[368 + 18];
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uint8_t * payload = buf + sizeof (SSUHeader);
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memcpy (payload, i2p::context.GetRouterIdentity ().publicKey, 256);
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memcpy (signedData + 256, payload, 256); // y
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payload += 256;
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*payload = 4; // we assume ipv4
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payload++;
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*(uint32_t *)(payload) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ());
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payload += 4;
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*(uint16_t *)(payload) = htobe16 (m_RemoteEndpoint.port ());
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payload += 2;
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memcpy (signedData + 512, payload - 6, 6); // remote endpoint IP and port
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*(uint32_t *)(signedData + 518) = htobe32 (address->host.to_v4 ().to_ulong ()); // our IP
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*(uint16_t *)(signedData + 522) = htobe16 (address->port); // our port
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*(uint32_t *)(payload) = 0; // relay tag, always 0 for now
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payload += 4;
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*(uint32_t *)(payload) = htobe32 (i2p::util::GetSecondsSinceEpoch ()); // signed on time
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payload += 4;
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memcpy (signedData + 524, payload - 8, 8); // relayTag and signed on time
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i2p::context.Sign (signedData, 532, payload); // DSA signature
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// TODO: fill padding with random data
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uint8_t iv[16];
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CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
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rnd.GenerateBlock (iv, 16); // random iv
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// encrypt signature and 8 bytes padding with newly created session key
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m_Encryption.SetKeyWithIV (m_SessionKey, 32, iv);
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m_Encryption.ProcessData (payload, payload, 48);
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// encrypt message with intro key
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FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CREATED, buf, 368, introKey, iv, introKey);
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m_State = eSessionStateRequestSent;
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m_Server->Send (buf, 368, m_RemoteEndpoint);
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}
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void SSUSession::SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress, uint32_t relayTag)
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{
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uint8_t buf[480 + 18];
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uint8_t * payload = buf + sizeof (SSUHeader);
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*payload = 1; // 1 fragment
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payload++; // info
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size_t identLen = sizeof (i2p::context.GetRouterIdentity ()); // 387 bytes
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*(uint16_t *)(payload) = htobe16 (identLen);
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payload += 2; // cursize
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memcpy (payload, (uint8_t *)&i2p::context.GetRouterIdentity (), identLen);
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payload += identLen;
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uint32_t signedOnTime = i2p::util::GetSecondsSinceEpoch ();
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*(uint32_t *)(payload) = htobe32 (signedOnTime); // signed on time
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payload += 4;
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size_t paddingSize = ((payload - buf) + 40)%16;
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if (paddingSize > 0) paddingSize = 16 - paddingSize;
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// TODO: fill padding
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payload += paddingSize; // padding size
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// signature
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uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, our signed on time
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memcpy (signedData, i2p::context.GetRouterIdentity ().publicKey, 256); // x
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memcpy (signedData + 256, y, 256); // y
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memcpy (signedData + 512, ourAddress, 6); // our address/port as seem by party
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*(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP
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*(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port
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*(uint32_t *)(signedData + 524) = htobe32 (relayTag); // relay tag
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*(uint32_t *)(signedData + 528) = htobe32 (signedOnTime); // signed on time
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i2p::context.Sign (signedData, 532, payload); // DSA signature
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uint8_t iv[16];
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CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
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rnd.GenerateBlock (iv, 16); // random iv
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// encrypt message with session key
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FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CONFIRMED, buf, 480, m_SessionKey, iv, m_MacKey);
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m_State = eSessionStateConfirmedSent;
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m_Server->Send (buf, 480, m_RemoteEndpoint);
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}
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void SSUSession::ProcessRelayResponse (uint8_t * buf, size_t len)
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{
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LogPrint ("Process relay response");
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auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
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if (!address)
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{
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LogPrint ("SSU is not supported");
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return;
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}
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if (Validate (buf, len, address->key))
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{
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Decrypt (buf, len, address->key);
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SSUHeader * header = (SSUHeader *)buf;
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if ((header->flag >> 4) == PAYLOAD_TYPE_RELAY_RESPONSE)
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{
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LogPrint ("Relay response received");
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m_State = eSessionRelayRequestReceived;
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uint8_t * payload = buf + sizeof (SSUHeader);
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payload++;
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boost::asio::ip::address_v4 remoteIP (be32toh (*(uint32_t* )(payload)));
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payload += 4;
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uint16_t remotePort = be16toh (*(uint16_t *)(payload));
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payload += 2;
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boost::asio::ip::udp::endpoint newRemoteEndpoint(remoteIP, remotePort);
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m_Server->ReassignSession (m_RemoteEndpoint, newRemoteEndpoint);
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m_RemoteEndpoint = newRemoteEndpoint;
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payload++;
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boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )(payload)));
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payload += 4;
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uint16_t ourPort = be16toh (*(uint16_t *)(payload));
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payload += 2;
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LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
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i2p::context.UpdateAddress (ourIP.to_string ().c_str ());
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}
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else
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LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));
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}
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}
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bool SSUSession::ProcessIntroKeyEncryptedMessage (uint8_t expectedPayloadType, uint8_t * buf, size_t len)
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{
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auto introKey = GetIntroKey ();
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if (introKey)
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{
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// use intro key for verification and decryption
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if (Validate (buf, len, introKey))
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{
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Decrypt (buf, len, introKey);
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SSUHeader * header = (SSUHeader *)buf;
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if ((header->flag >> 4) == expectedPayloadType)
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{
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CreateAESandMacKey (buf + sizeof (SSUHeader), m_SessionKey, m_MacKey);
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return true;
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}
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else
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LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));
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}
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else
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LogPrint ("MAC verification failed");
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}
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else
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LogPrint ("SSU is not supported");
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return false;
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}
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void SSUSession::FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len,
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const uint8_t * aesKey, const uint8_t * iv, const uint8_t * macKey)
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{
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if (len < sizeof (SSUHeader))
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{
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LogPrint ("Unexpected SSU packet length ", len);
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return;
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}
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SSUHeader * header = (SSUHeader *)buf;
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memcpy (header->iv, iv, 16);
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header->flag = payloadType << 4; // MSB is 0
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header->time = htobe32 (i2p::util::GetSecondsSinceEpoch ());
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uint8_t * encrypted = &header->flag;
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uint16_t encryptedLen = len - (encrypted - buf);
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m_Encryption.SetKeyWithIV (aesKey, 32, iv);
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m_Encryption.ProcessData (encrypted, encrypted, encryptedLen);
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// assume actual buffer size is 18 (16 + 2) bytes more
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memcpy (buf + len, iv, 16);
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*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
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i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, macKey, header->mac);
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}
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void SSUSession::Decrypt (uint8_t * buf, size_t len, const uint8_t * aesKey)
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{
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if (len < sizeof (SSUHeader))
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{
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LogPrint ("Unexpected SSU packet length ", len);
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return;
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}
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SSUHeader * header = (SSUHeader *)buf;
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uint8_t * encrypted = &header->flag;
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uint16_t encryptedLen = len - (encrypted - buf);
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m_Decryption.SetKeyWithIV (aesKey, 32, header->iv);
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encryptedLen = (encryptedLen/16)*16; // make sure 16 bytes boundary
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m_Decryption.ProcessData (encrypted, encrypted, encryptedLen);
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}
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bool SSUSession::Validate (uint8_t * buf, size_t len, const uint8_t * macKey)
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{
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if (len < sizeof (SSUHeader))
|
|
{
|
|
LogPrint ("Unexpected SSU packet length ", len);
|
|
return false;
|
|
}
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
uint8_t * encrypted = &header->flag;
|
|
uint16_t encryptedLen = len - (encrypted - buf);
|
|
// assume actual buffer size is 18 (16 + 2) bytes more
|
|
memcpy (buf + len, header->iv, 16);
|
|
*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
|
|
uint8_t digest[16];
|
|
i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, macKey, digest);
|
|
return !memcmp (header->mac, digest, 16);
|
|
}
|
|
|
|
void SSUSession::Connect ()
|
|
{
|
|
SendSessionRequest ();
|
|
}
|
|
|
|
void SSUSession::ConnectThroughIntroducer (const i2p::data::RouterInfo::Introducer& introducer)
|
|
{
|
|
SendRelayRequest (introducer);
|
|
}
|
|
|
|
void SSUSession::Close ()
|
|
{
|
|
SendSesionDestroyed ();
|
|
if (!m_DelayedMessages.empty ())
|
|
{
|
|
for (auto it :m_DelayedMessages)
|
|
delete it;
|
|
m_DelayedMessages.clear ();
|
|
}
|
|
}
|
|
|
|
void SSUSession::Established ()
|
|
{
|
|
SendI2NPMessage (CreateDatabaseStoreMsg ());
|
|
if (!m_DelayedMessages.empty ())
|
|
{
|
|
for (auto it :m_DelayedMessages)
|
|
Send (it);
|
|
m_DelayedMessages.clear ();
|
|
}
|
|
}
|
|
|
|
const uint8_t * SSUSession::GetIntroKey () const
|
|
{
|
|
if (m_RemoteRouter)
|
|
{
|
|
// we are client
|
|
auto address = m_RemoteRouter->GetSSUAddress ();
|
|
return address ? address->key : nullptr;
|
|
}
|
|
else
|
|
{
|
|
// we are server
|
|
auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
|
|
return address ? address->key : nullptr;
|
|
}
|
|
}
|
|
|
|
void SSUSession::SendI2NPMessage (I2NPMessage * msg)
|
|
{
|
|
if (msg)
|
|
{
|
|
if (m_State == eSessionStateEstablished)
|
|
Send (msg);
|
|
else
|
|
m_DelayedMessages.push_back (msg);
|
|
}
|
|
}
|
|
|
|
void SSUSession::ProcessData (uint8_t * buf, size_t len)
|
|
{
|
|
//uint8_t * start = buf;
|
|
uint8_t flag = *buf;
|
|
buf++;
|
|
LogPrint ("Process SSU data flags=", (int)flag);
|
|
if (flag & DATA_FLAG_EXPLICIT_ACKS_INCLUDED)
|
|
{
|
|
// explicit ACKs
|
|
uint8_t numAcks =*buf;
|
|
buf++;
|
|
// TODO: process ACKs
|
|
buf += numAcks*4;
|
|
}
|
|
if (flag & DATA_FLAG_ACK_BITFIELDS_INCLUDED)
|
|
{
|
|
// explicit ACK bitfields
|
|
uint8_t numBitfields =*buf;
|
|
buf++;
|
|
for (int i = 0; i < numBitfields; i++)
|
|
{
|
|
buf += 4; // msgID
|
|
// TODO: process ACH bitfields
|
|
while (*buf & 0x80) // not last
|
|
buf++;
|
|
buf++; // last byte
|
|
}
|
|
}
|
|
uint8_t numFragments = *buf; // number of fragments
|
|
buf++;
|
|
for (int i = 0; i < numFragments; i++)
|
|
{
|
|
uint32_t msgID = be32toh (*(uint32_t *)buf); // message ID
|
|
buf += 4;
|
|
uint8_t frag[4];
|
|
frag[0] = 0;
|
|
memcpy (frag + 1, buf, 3);
|
|
buf += 3;
|
|
uint32_t fragmentInfo = be32toh (*(uint32_t *)frag); // fragment info
|
|
uint16_t fragmentSize = fragmentInfo & 0x1FFF; // bits 0 - 13
|
|
bool isLast = fragmentInfo & 0x010000; // bit 16
|
|
uint8_t fragmentNum = fragmentInfo >> 17; // bits 23 - 17
|
|
LogPrint ("SSU data fragment ", (int)fragmentNum, " of message ", msgID, " size=", (int)fragmentSize, isLast ? " last" : " non-last");
|
|
I2NPMessage * msg = nullptr;
|
|
if (fragmentNum > 0) // follow-up fragment
|
|
{
|
|
auto it = m_IncomleteMessages.find (msgID);
|
|
if (it != m_IncomleteMessages.end ())
|
|
{
|
|
msg = it->second;
|
|
memcpy (msg->buf + msg->len, buf, fragmentSize);
|
|
msg->len += fragmentSize;
|
|
}
|
|
else
|
|
// TODO:
|
|
LogPrint ("Unexpected follow-on fragment ", fragmentNum, " of message ", msgID);
|
|
}
|
|
else // first fragment
|
|
{
|
|
msg = NewI2NPMessage ();
|
|
memcpy (msg->GetSSUHeader (), buf, fragmentSize);
|
|
msg->len += fragmentSize - sizeof (I2NPHeaderShort);
|
|
}
|
|
|
|
if (msg)
|
|
{
|
|
if (!fragmentNum && !isLast)
|
|
m_IncomleteMessages[msgID] = msg;
|
|
if (isLast)
|
|
{
|
|
SendMsgAck (msgID);
|
|
if (fragmentNum > 0)
|
|
m_IncomleteMessages.erase (msgID);
|
|
msg->FromSSU (msgID);
|
|
if (m_State == eSessionStateEstablished)
|
|
i2p::HandleI2NPMessage (msg, false);
|
|
else
|
|
{
|
|
// we expect DeliveryStatus
|
|
if (msg->GetHeader ()->typeID == eI2NPDeliveryStatus)
|
|
{
|
|
LogPrint ("SSU session established");
|
|
m_State = eSessionStateEstablished;
|
|
Established ();
|
|
}
|
|
else
|
|
LogPrint ("SSU unexpected message ", (int)msg->GetHeader ()->typeID);
|
|
DeleteI2NPMessage (msg);
|
|
}
|
|
}
|
|
}
|
|
buf += fragmentSize;
|
|
}
|
|
}
|
|
|
|
void SSUSession::SendMsgAck (uint32_t msgID)
|
|
{
|
|
uint8_t buf[48 + 18]; // actual length is 44 = 37 + 7 but pad it to multiple of 16
|
|
uint8_t iv[16];
|
|
uint8_t * payload = buf + sizeof (SSUHeader);
|
|
*payload = DATA_FLAG_EXPLICIT_ACKS_INCLUDED; // flag
|
|
payload++;
|
|
*payload = 1; // number of ACKs
|
|
payload++;
|
|
*(uint32_t *)(payload) = htobe32 (msgID); // msgID
|
|
payload += 4;
|
|
*payload = 0; // number of fragments
|
|
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
// encrypt message with session key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, 48, m_SessionKey, iv, m_MacKey);
|
|
m_Server->Send (buf, 48, m_RemoteEndpoint);
|
|
}
|
|
|
|
void SSUSession::SendSesionDestroyed ()
|
|
{
|
|
uint8_t buf[48 + 18], iv[16];
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
if (m_State == eSessionStateEstablished)
|
|
// encrypt message with session key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_DESTROYED, buf, 48, m_SessionKey, iv, m_MacKey);
|
|
else
|
|
{
|
|
auto introKey = GetIntroKey ();
|
|
if (introKey)
|
|
// encrypt message with intro key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_DESTROYED, buf, 48, introKey, iv, introKey);
|
|
else
|
|
{
|
|
LogPrint ("SSU: can't send SessionDestroyed message");
|
|
return;
|
|
}
|
|
}
|
|
m_Server->Send (buf, 48, m_RemoteEndpoint);
|
|
}
|
|
|
|
void SSUSession::Send (i2p::I2NPMessage * msg)
|
|
{
|
|
uint32_t msgID = htobe32 (msg->ToSSU ());
|
|
size_t payloadSize = SSU_MTU - sizeof (SSUHeader) - 9; // 9 = flag + #frg(1) + messageID(4) + frag info (3)
|
|
size_t len = msg->GetLength ();
|
|
uint8_t * msgBuf = msg->GetSSUHeader ();
|
|
|
|
uint32_t fragmentNum = 0;
|
|
while (len > 0)
|
|
{
|
|
uint8_t buf[SSU_MTU + 18], iv[16], * payload = buf + sizeof (SSUHeader);
|
|
*payload = DATA_FLAG_WANT_REPLY; // for compatibility
|
|
payload++;
|
|
*payload = 1; // always 1 message fragment per message
|
|
payload++;
|
|
*(uint32_t *)payload = msgID;
|
|
payload += 4;
|
|
bool isLast = (len <= payloadSize);
|
|
size_t size = isLast ? len : payloadSize;
|
|
uint32_t fragmentInfo = (fragmentNum << 17);
|
|
if (isLast)
|
|
fragmentInfo |= 0x010000;
|
|
|
|
fragmentInfo |= size;
|
|
fragmentInfo = htobe32 (fragmentInfo);
|
|
memcpy (payload, (uint8_t *)(&fragmentInfo) + 1, 3);
|
|
payload += 3;
|
|
memcpy (payload, msgBuf, size);
|
|
|
|
size += payload - buf;
|
|
if (size % 16) // make sure 16 bytes boundary
|
|
size = (size/16 + 1)*16;
|
|
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
// encrypt message with session key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, size, m_SessionKey, iv, m_MacKey);
|
|
m_Server->Send (buf, size, m_RemoteEndpoint);
|
|
|
|
if (!isLast)
|
|
{
|
|
len -= payloadSize;
|
|
msgBuf += payloadSize;
|
|
}
|
|
else
|
|
len = 0;
|
|
fragmentNum++;
|
|
}
|
|
}
|
|
|
|
SSUServer::SSUServer (boost::asio::io_service& service, int port):
|
|
m_Endpoint (boost::asio::ip::udp::v4 (), port), m_Socket (service, m_Endpoint)
|
|
{
|
|
m_Socket.set_option (boost::asio::socket_base::receive_buffer_size (65535));
|
|
m_Socket.set_option (boost::asio::socket_base::send_buffer_size (65535));
|
|
}
|
|
|
|
SSUServer::~SSUServer ()
|
|
{
|
|
for (auto it: m_Sessions)
|
|
delete it.second;
|
|
}
|
|
|
|
void SSUServer::Start ()
|
|
{
|
|
Receive ();
|
|
}
|
|
|
|
void SSUServer::Stop ()
|
|
{
|
|
DeleteAllSessions ();
|
|
m_Socket.close ();
|
|
}
|
|
|
|
void SSUServer::Send (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& to)
|
|
{
|
|
m_Socket.send_to (boost::asio::buffer (buf, len), to);
|
|
LogPrint ("SSU sent ", len, " bytes");
|
|
}
|
|
|
|
void SSUServer::Receive ()
|
|
{
|
|
m_Socket.async_receive_from (boost::asio::buffer (m_ReceiveBuffer, SSU_MTU), m_SenderEndpoint,
|
|
boost::bind (&SSUServer::HandleReceivedFrom, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
|
|
}
|
|
|
|
void SSUServer::HandleReceivedFrom (const boost::system::error_code& ecode, std::size_t bytes_transferred)
|
|
{
|
|
if (!ecode)
|
|
{
|
|
LogPrint ("SSU received ", bytes_transferred, " bytes");
|
|
SSUSession * session = nullptr;
|
|
auto it = m_Sessions.find (m_SenderEndpoint);
|
|
if (it != m_Sessions.end ())
|
|
session = it->second;
|
|
if (!session)
|
|
{
|
|
session = new SSUSession (this, m_SenderEndpoint);
|
|
m_Sessions[m_SenderEndpoint] = session;
|
|
LogPrint ("New SSU session from ", m_SenderEndpoint.address ().to_string (), ":", m_SenderEndpoint.port (), " created");
|
|
}
|
|
session->ProcessNextMessage (m_ReceiveBuffer, bytes_transferred, m_SenderEndpoint);
|
|
Receive ();
|
|
}
|
|
else
|
|
LogPrint ("SSU receive error: ", ecode.message ());
|
|
}
|
|
|
|
SSUSession * SSUServer::GetSession (const i2p::data::RouterInfo * router)
|
|
{
|
|
SSUSession * session = nullptr;
|
|
if (router)
|
|
{
|
|
auto address = router->GetSSUAddress ();
|
|
if (address)
|
|
{
|
|
boost::asio::ip::udp::endpoint remoteEndpoint (address->host, address->port);
|
|
auto it = m_Sessions.find (remoteEndpoint);
|
|
if (it != m_Sessions.end ())
|
|
session = it->second;
|
|
else
|
|
{
|
|
// otherwise create new session
|
|
if (!router->UsesIntroducer ())
|
|
{
|
|
// connect directly
|
|
session = new SSUSession (this, remoteEndpoint, router);
|
|
m_Sessions[remoteEndpoint] = session;
|
|
LogPrint ("New SSU session to [", router->GetIdentHashAbbreviation (), "] ",
|
|
remoteEndpoint.address ().to_string (), ":", remoteEndpoint.port (), " created");
|
|
session->Connect ();
|
|
}
|
|
else
|
|
{
|
|
// connect to introducer
|
|
auto& introducer = address->introducers[0]; // TODO:
|
|
boost::asio::ip::udp::endpoint introducerEndpoint (introducer.iHost, introducer.iPort);
|
|
session = new SSUSession (this, introducerEndpoint, router);
|
|
m_Sessions[introducerEndpoint] = session;
|
|
LogPrint ("New SSU session to [", router->GetIdentHashAbbreviation (),
|
|
"] created through introducer ", introducerEndpoint.address ().to_string (), ":", introducerEndpoint.port ());
|
|
session->ConnectThroughIntroducer (introducer);
|
|
}
|
|
}
|
|
}
|
|
else
|
|
LogPrint ("Router ", router->GetIdentHashAbbreviation (), " doesn't have SSU address");
|
|
}
|
|
return session;
|
|
}
|
|
|
|
void SSUServer::DeleteSession (SSUSession * session)
|
|
{
|
|
if (session)
|
|
{
|
|
session->Close ();
|
|
m_Sessions.erase (session->GetRemoteEndpoint ());
|
|
delete session;
|
|
}
|
|
}
|
|
|
|
void SSUServer::DeleteAllSessions ()
|
|
{
|
|
for (auto it: m_Sessions)
|
|
{
|
|
it.second->Close ();
|
|
delete it.second;
|
|
}
|
|
m_Sessions.clear ();
|
|
}
|
|
|
|
void SSUServer::ReassignSession (const boost::asio::ip::udp::endpoint& oldEndpoint, const boost::asio::ip::udp::endpoint& newEndpoint)
|
|
{
|
|
auto it = m_Sessions.find (oldEndpoint);
|
|
if (it != m_Sessions.end ())
|
|
{
|
|
m_Sessions.erase (it);
|
|
m_Sessions[newEndpoint] = it->second;
|
|
LogPrint ("SSU session ressigned from ", oldEndpoint.address ().to_string (), ":", oldEndpoint.port (),
|
|
" to ", newEndpoint.address ().to_string (), ":", newEndpoint.port ());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|