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i2pd/SSU.cpp
orignal 180fbcdac6 ignore zero length packets
2014-08-19 11:03:08 -04:00

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#include <string.h>
#include <boost/bind.hpp>
#include <cryptopp/dh.h>
#include <cryptopp/sha.h>
#include "CryptoConst.h"
#include "Log.h"
#include "Timestamp.h"
#include "RouterContext.h"
#include "Transports.h"
#include "hmac.h"
#include "SSU.h"
namespace i2p
{
namespace ssu
{
SSUSession::SSUSession (SSUServer& server, boost::asio::ip::udp::endpoint& remoteEndpoint,
const i2p::data::RouterInfo * router, bool peerTest ):
m_Server (server), m_RemoteEndpoint (remoteEndpoint), m_RemoteRouter (router),
m_Timer (m_Server.GetService ()), m_PeerTest (peerTest), m_State (eSessionStateUnknown),
m_IsSessionKey (false), m_RelayTag (0), m_Data (*this),
m_NumSentBytes (0), m_NumReceivedBytes (0)
{
m_DHKeysPair = i2p::transports.GetNextDHKeysPair ();
}
SSUSession::~SSUSession ()
{
delete m_DHKeysPair;
}
void SSUSession::CreateAESandMacKey (const uint8_t * pubKey)
{
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
uint8_t sharedKey[256];
if (!dh.Agree (sharedKey, m_DHKeysPair->privateKey, pubKey))
{
LogPrint ("Couldn't create shared key");
return;
};
if (sharedKey[0] & 0x80)
{
m_SessionKey[0] = 0;
memcpy (m_SessionKey + 1, sharedKey, 31);
memcpy (m_MacKey, sharedKey + 31, 32);
}
else if (sharedKey[0])
{
memcpy (m_SessionKey, sharedKey, 32);
memcpy (m_MacKey, sharedKey + 32, 32);
}
else
{
// find first non-zero byte
uint8_t * nonZero = sharedKey + 1;
while (!*nonZero)
{
nonZero++;
if (nonZero - sharedKey > 32)
{
LogPrint ("First 32 bytes of shared key is all zeros. Ignored");
return;
}
}
memcpy (m_SessionKey, nonZero, 32);
CryptoPP::SHA256().CalculateDigest(m_MacKey, nonZero, 64 - (nonZero - sharedKey));
}
m_IsSessionKey = true;
m_SessionKeyEncryption.SetKey (m_SessionKey);
m_SessionKeyDecryption.SetKey (m_SessionKey);
}
void SSUSession::ProcessNextMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
m_NumReceivedBytes += len;
if (m_State == eSessionStateIntroduced)
{
// HolePunch received
LogPrint ("SSU HolePunch of ", len, " bytes received");
m_State = eSessionStateUnknown;
Connect ();
}
else
{
if (m_State == eSessionStateEstablished)
ScheduleTermination ();
if (!len) return; // ignore zero-length packets
if (m_IsSessionKey && Validate (buf, len, m_MacKey)) // try session key first
DecryptSessionKey (buf, len);
else
{
// try intro key depending on side
auto introKey = GetIntroKey ();
if (introKey && Validate (buf, len, introKey))
Decrypt (buf, len, introKey);
else
{
// try own intro key
auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
if (!address)
{
LogPrint ("SSU is not supported");
return;
}
if (Validate (buf, len, address->key))
Decrypt (buf, len, address->key);
else
{
LogPrint ("MAC verification failed ", len, " bytes from ", senderEndpoint);
m_Server.DeleteSession (this);
return;
}
}
}
// successfully decrypted
ProcessMessage (buf, len, senderEndpoint);
}
}
void SSUSession::ProcessMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
SSUHeader * header = (SSUHeader *)buf;
switch (header->GetPayloadType ())
{
case PAYLOAD_TYPE_DATA:
LogPrint ("SSU data received");
ProcessData (buf + sizeof (SSUHeader), len - sizeof (SSUHeader));
break;
case PAYLOAD_TYPE_SESSION_REQUEST:
ProcessSessionRequest (buf, len, senderEndpoint);
break;
case PAYLOAD_TYPE_SESSION_CREATED:
ProcessSessionCreated (buf, len);
break;
case PAYLOAD_TYPE_SESSION_CONFIRMED:
ProcessSessionConfirmed (buf, len);
break;
case PAYLOAD_TYPE_PEER_TEST:
LogPrint ("SSU peer test received");
ProcessPeerTest (buf + sizeof (SSUHeader), len - sizeof (SSUHeader), senderEndpoint);
break;
case PAYLOAD_TYPE_SESSION_DESTROYED:
{
LogPrint ("SSU session destroy received");
m_Server.DeleteSession (this); // delete this
break;
}
case PAYLOAD_TYPE_RELAY_RESPONSE:
ProcessRelayResponse (buf, len);
if (m_State != eSessionStateEstablished)
m_Server.DeleteSession (this);
break;
case PAYLOAD_TYPE_RELAY_REQUEST:
LogPrint ("SSU relay request received");
ProcessRelayRequest (buf + sizeof (SSUHeader), len - sizeof (SSUHeader));
break;
case PAYLOAD_TYPE_RELAY_INTRO:
LogPrint ("SSU relay intro received");
ProcessRelayIntro (buf + sizeof (SSUHeader), len - sizeof (SSUHeader));
break;
default:
LogPrint ("Unexpected SSU payload type ", (int)header->GetPayloadType ());
}
}
void SSUSession::ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
LogPrint ("Session request received");
m_RemoteEndpoint = senderEndpoint;
CreateAESandMacKey (buf + sizeof (SSUHeader));
SendSessionCreated (buf + sizeof (SSUHeader));
}
void SSUSession::ProcessSessionCreated (uint8_t * buf, size_t len)
{
if (!m_RemoteRouter)
{
LogPrint ("Unsolicited session created message");
return;
}
LogPrint ("Session created received");
m_Timer.cancel (); // connect timer
uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, signed on time
uint8_t * payload = buf + sizeof (SSUHeader);
uint8_t * y = payload;
CreateAESandMacKey (y);
memcpy (signedData, m_DHKeysPair->publicKey, 256); // x
memcpy (signedData + 256, y, 256); // y
payload += 256;
payload += 1; // size, assume 4
uint8_t * ourAddress = payload;
boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )ourAddress));
payload += 4; // address
uint16_t ourPort = be16toh (*(uint16_t *)payload);
payload += 2; // port
memcpy (signedData + 512, ourAddress, 6); // our IP and port
LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
i2p::context.UpdateAddress (ourIP.to_string ().c_str ());
*(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP
*(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port
memcpy (signedData + 524, payload, 8); // relayTag and signed on time
m_RelayTag = be32toh (*(uint32_t *)payload);
payload += 4; // relayTag
payload += 4; // signed on time
// decrypt DSA signature
m_SessionKeyDecryption.SetIV (((SSUHeader *)buf)->iv);
m_SessionKeyDecryption.Decrypt (payload, 48, payload);
// verify
CryptoPP::DSA::PublicKey pubKey;
pubKey.Initialize (i2p::crypto::dsap, i2p::crypto::dsaq, i2p::crypto::dsag, CryptoPP::Integer (m_RemoteRouter->GetRouterIdentity ().signingKey, 128));
CryptoPP::DSA::Verifier verifier (pubKey);
if (!verifier.VerifyMessage (signedData, 532, payload, 40))
LogPrint ("SSU signature verification failed");
SendSessionConfirmed (y, ourAddress);
}
void SSUSession::ProcessSessionConfirmed (uint8_t * buf, size_t len)
{
LogPrint ("Session confirmed received");
SendI2NPMessage (CreateDeliveryStatusMsg (0));
Established ();
}
void SSUSession::SendSessionRequest ()
{
auto introKey = GetIntroKey ();
if (!introKey)
{
LogPrint ("SSU is not supported");
return;
}
uint8_t buf[304 + 18]; // 304 bytes for ipv4 (320 for ipv6)
uint8_t * payload = buf + sizeof (SSUHeader);
memcpy (payload, m_DHKeysPair->publicKey, 256); // x
payload[256] = 4; // we assume ipv4
*(uint32_t *)(payload + 257) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ());
uint8_t iv[16];
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (iv, 16); // random iv
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_REQUEST, buf, 304, introKey, iv, introKey);
m_Server.Send (buf, 304, m_RemoteEndpoint);
}
void SSUSession::SendRelayRequest (uint32_t iTag, const uint8_t * iKey)
{
auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
if (!address)
{
LogPrint ("SSU is not supported");
return;
}
uint8_t buf[96 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
*(uint32_t *)payload = htobe32 (iTag);
payload += 4;
*payload = 0; // no address
payload++;
*(uint16_t *)payload = 0; // port = 0
payload += 2;
*payload = 0; // challenge
payload++;
memcpy (payload, address->key, 32);
payload += 32;
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
*(uint32_t *)payload = htobe32 (rnd.GenerateWord32 ()); // nonce
uint8_t iv[16];
rnd.GenerateBlock (iv, 16); // random iv
if (m_State == eSessionStateEstablished)
FillHeaderAndEncrypt (PAYLOAD_TYPE_RELAY_REQUEST, buf, 96, m_SessionKey, iv, m_MacKey);
else
FillHeaderAndEncrypt (PAYLOAD_TYPE_RELAY_REQUEST, buf, 96, iKey, iv, iKey);
m_Server.Send (buf, 96, m_RemoteEndpoint);
}
void SSUSession::SendSessionCreated (const uint8_t * x)
{
auto introKey = GetIntroKey ();
auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
if (!introKey || !address)
{
LogPrint ("SSU is not supported");
return;
}
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
uint8_t signedData[532]; // x,y, remote IP, remote port, our IP, our port, relayTag, signed on time
memcpy (signedData, x, 256); // x
uint8_t buf[368 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
memcpy (payload, m_DHKeysPair->publicKey, 256);
memcpy (signedData + 256, payload, 256); // y
payload += 256;
*payload = 4; // we assume ipv4
payload++;
*(uint32_t *)(payload) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ());
payload += 4;
*(uint16_t *)(payload) = htobe16 (m_RemoteEndpoint.port ());
payload += 2;
memcpy (signedData + 512, payload - 6, 6); // remote endpoint IP and port
*(uint32_t *)(signedData + 518) = htobe32 (address->host.to_v4 ().to_ulong ()); // our IP
*(uint16_t *)(signedData + 522) = htobe16 (address->port); // our port
uint32_t relayTag = 0;
if (i2p::context.GetRouterInfo ().IsIntroducer ())
{
rnd.GenerateWord32 (relayTag);
m_Server.AddRelay (relayTag, m_RemoteEndpoint);
}
*(uint32_t *)(payload) = htobe32 (relayTag);
payload += 4; // relay tag
*(uint32_t *)(payload) = htobe32 (i2p::util::GetSecondsSinceEpoch ()); // signed on time
payload += 4;
memcpy (signedData + 524, payload - 8, 8); // relayTag and signed on time
i2p::context.Sign (signedData, 532, payload); // DSA signature
// TODO: fill padding with random data
uint8_t iv[16];
rnd.GenerateBlock (iv, 16); // random iv
// encrypt signature and 8 bytes padding with newly created session key
m_SessionKeyEncryption.SetIV (iv);
m_SessionKeyEncryption.Encrypt (payload, 48, payload);
// encrypt message with intro key
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CREATED, buf, 368, introKey, iv, introKey);
Send (buf, 368);
}
void SSUSession::SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress)
{
uint8_t buf[480 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
*payload = 1; // 1 fragment
payload++; // info
size_t identLen = sizeof (i2p::context.GetRouterIdentity ()); // 387 bytes
*(uint16_t *)(payload) = htobe16 (identLen);
payload += 2; // cursize
memcpy (payload, (uint8_t *)&i2p::context.GetRouterIdentity (), identLen);
payload += identLen;
uint32_t signedOnTime = i2p::util::GetSecondsSinceEpoch ();
*(uint32_t *)(payload) = htobe32 (signedOnTime); // signed on time
payload += 4;
size_t paddingSize = ((payload - buf) + 40)%16;
if (paddingSize > 0) paddingSize = 16 - paddingSize;
// TODO: fill padding
payload += paddingSize; // padding size
// signature
uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, our signed on time
memcpy (signedData, m_DHKeysPair->publicKey, 256); // x
memcpy (signedData + 256, y, 256); // y
memcpy (signedData + 512, ourAddress, 6); // our address/port as seem by party
*(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP
*(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port
*(uint32_t *)(signedData + 524) = htobe32 (m_RelayTag); // relay tag
*(uint32_t *)(signedData + 528) = htobe32 (signedOnTime); // signed on time
i2p::context.Sign (signedData, 532, payload); // DSA signature
uint8_t iv[16];
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (iv, 16); // random iv
// encrypt message with session key
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CONFIRMED, buf, 480, m_SessionKey, iv, m_MacKey);
Send (buf, 480);
}
void SSUSession::ProcessRelayRequest (uint8_t * buf, size_t len)
{
uint32_t relayTag = be32toh (*(uint32_t *)buf);
auto session = m_Server.FindRelaySession (relayTag);
if (session)
{
buf += 4; // relay tag
uint8_t size = *buf;
if (size == 4)
{
buf++; // size
boost::asio::ip::address_v4 address (be32toh (*(uint32_t* )buf));
buf += 4; // address
uint16_t port = be16toh (*(uint16_t *)buf);
buf += 2; // port
uint8_t challengeSize = *buf;
buf++; // challenge size
buf += challengeSize;
uint8_t * introKey = buf;
buf += 32; // introkey
uint32_t nonce = be32toh (*(uint32_t *)buf);
boost::asio::ip::udp::endpoint from (address, port);
SendRelayResponse (nonce, from, introKey, session->m_RemoteEndpoint);
SendRelayIntro (session, from);
}
else
LogPrint ("Address size ", size, " is not supported");
}
}
void SSUSession::SendRelayResponse (uint32_t nonce, const boost::asio::ip::udp::endpoint& from, const uint8_t * introKey, const boost::asio::ip::udp::endpoint& to)
{
uint8_t buf[64 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
// Charlie
*payload = 4;
payload++; // size
*(uint32_t *)payload = htobe32 (to.address ().to_v4 ().to_ulong ()); // Charlie's IP
payload += 4; // address
*(uint16_t *)payload = htobe16 (to.port ()); // Charlie's port
payload += 2; // port
// Alice
*payload = 4;
payload++; // size
*(uint32_t *)payload = htobe32 (from.address ().to_v4 ().to_ulong ()); // Alice's IP
payload += 4; // address
*(uint16_t *)payload = htobe16 (from.port ()); // Alice's port
payload += 2; // port
*(uint32_t *)payload = htobe32 (nonce);
uint8_t iv[16];
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (iv, 16); // random iv
FillHeaderAndEncrypt (PAYLOAD_TYPE_RELAY_RESPONSE, buf, 64, introKey, iv, introKey);
m_Server.Send (buf, 64, from);
}
void SSUSession::SendRelayIntro (SSUSession * session, const boost::asio::ip::udp::endpoint& from)
{
if (!session) return;
uint8_t buf[48 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
*payload = 4;
payload++; // size
*(uint32_t *)payload = htobe32 (from.address ().to_v4 ().to_ulong ()); // Alice's IP
payload += 4; // address
*(uint16_t *)payload = htobe16 (from.port ()); // Alice's port
payload += 2; // port
*payload = 0; // challenge size
uint8_t iv[16];
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (iv, 16); // random iv
FillHeaderAndEncrypt (PAYLOAD_TYPE_RELAY_INTRO, buf, 48, session->m_SessionKey, iv, session->m_MacKey);
m_Server.Send (buf, 48, session->m_RemoteEndpoint);
}
void SSUSession::ProcessRelayResponse (uint8_t * buf, size_t len)
{
LogPrint ("Relay response received");
uint8_t * payload = buf + sizeof (SSUHeader);
payload++; // remote size
//boost::asio::ip::address_v4 remoteIP (be32toh (*(uint32_t* )(payload)));
payload += 4; // remote address
//uint16_t remotePort = be16toh (*(uint16_t *)(payload));
payload += 2; // remote port
payload++; // our size
boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )(payload)));
payload += 4; // our address
uint16_t ourPort = be16toh (*(uint16_t *)(payload));
payload += 2; // our port
LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
i2p::context.UpdateAddress (ourIP.to_string ().c_str ());
}
void SSUSession::ProcessRelayIntro (uint8_t * buf, size_t len)
{
uint8_t size = *buf;
if (size == 4)
{
buf++; // size
boost::asio::ip::address_v4 address (be32toh (*(uint32_t* )buf));
buf += 4; // address
uint16_t port = be16toh (*(uint16_t *)buf);
// send hole punch of 1 byte
m_Server.Send (buf, 1, boost::asio::ip::udp::endpoint (address, port));
}
else
LogPrint ("Address size ", size, " is not supported");
}
void SSUSession::FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len,
const uint8_t * aesKey, const uint8_t * iv, const uint8_t * macKey)
{
if (len < sizeof (SSUHeader))
{
LogPrint ("Unexpected SSU packet length ", len);
return;
}
SSUHeader * header = (SSUHeader *)buf;
memcpy (header->iv, iv, 16);
header->flag = payloadType << 4; // MSB is 0
header->time = htobe32 (i2p::util::GetSecondsSinceEpoch ());
uint8_t * encrypted = &header->flag;
uint16_t encryptedLen = len - (encrypted - buf);
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (aesKey);
encryption.SetIV (iv);
encryption.Encrypt (encrypted, encryptedLen, encrypted);
// assume actual buffer size is 18 (16 + 2) bytes more
memcpy (buf + len, iv, 16);
*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, macKey, header->mac);
}
void SSUSession::FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len)
{
if (len < sizeof (SSUHeader))
{
LogPrint ("Unexpected SSU packet length ", len);
return;
}
SSUHeader * header = (SSUHeader *)buf;
i2p::context.GetRandomNumberGenerator ().GenerateBlock (header->iv, 16); // random iv
m_SessionKeyEncryption.SetIV (header->iv);
header->flag = payloadType << 4; // MSB is 0
header->time = htobe32 (i2p::util::GetSecondsSinceEpoch ());
uint8_t * encrypted = &header->flag;
uint16_t encryptedLen = len - (encrypted - buf);
m_SessionKeyEncryption.Encrypt (encrypted, encryptedLen, encrypted);
// assume actual buffer size is 18 (16 + 2) bytes more
memcpy (buf + len, header->iv, 16);
*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, m_MacKey, header->mac);
}
void SSUSession::Decrypt (uint8_t * buf, size_t len, const uint8_t * aesKey)
{
if (len < sizeof (SSUHeader))
{
LogPrint ("Unexpected SSU packet length ", len);
return;
}
SSUHeader * header = (SSUHeader *)buf;
uint8_t * encrypted = &header->flag;
uint16_t encryptedLen = len - (encrypted - buf);
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (aesKey);
decryption.SetIV (header->iv);
decryption.Decrypt (encrypted, encryptedLen, encrypted);
}
void SSUSession::DecryptSessionKey (uint8_t * buf, size_t len)
{
if (len < sizeof (SSUHeader))
{
LogPrint ("Unexpected SSU packet length ", len);
return;
}
SSUHeader * header = (SSUHeader *)buf;
uint8_t * encrypted = &header->flag;
uint16_t encryptedLen = len - (encrypted - buf);
if (encryptedLen > 0)
{
m_SessionKeyDecryption.SetIV (header->iv);
m_SessionKeyDecryption.Decrypt (encrypted, encryptedLen, encrypted);
}
}
bool SSUSession::Validate (uint8_t * buf, size_t len, const uint8_t * macKey)
{
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 ()
{
if (m_State == eSessionStateUnknown)
{
// set connect timer
m_Timer.expires_from_now (boost::posix_time::seconds(SSU_CONNECT_TIMEOUT));
m_Timer.async_wait (boost::bind (&SSUSession::HandleConnectTimer,
this, boost::asio::placeholders::error));
SendSessionRequest ();
}
}
void SSUSession::HandleConnectTimer (const boost::system::error_code& ecode)
{
if (!ecode)
{
// timeout expired
LogPrint ("SSU session was not established after ", SSU_CONNECT_TIMEOUT, " second");
Failed ();
}
}
void SSUSession::Introduce (uint32_t iTag, const uint8_t * iKey)
{
if (m_State == eSessionStateUnknown)
{
// set connect timer
m_Timer.expires_from_now (boost::posix_time::seconds(SSU_CONNECT_TIMEOUT));
m_Timer.async_wait (boost::bind (&SSUSession::HandleConnectTimer,
this, boost::asio::placeholders::error));
}
SendRelayRequest (iTag, iKey);
}
void SSUSession::WaitForIntroduction ()
{
m_State = eSessionStateIntroduced;
// set connect timer
m_Timer.expires_from_now (boost::posix_time::seconds(SSU_CONNECT_TIMEOUT));
m_Timer.async_wait (boost::bind (&SSUSession::HandleConnectTimer,
this, boost::asio::placeholders::error));
}
void SSUSession::Close ()
{
SendSesionDestroyed ();
if (!m_DelayedMessages.empty ())
{
for (auto it :m_DelayedMessages)
DeleteI2NPMessage (it);
m_DelayedMessages.clear ();
}
}
void SSUSession::Established ()
{
m_State = eSessionStateEstablished;
SendI2NPMessage (CreateDatabaseStoreMsg ());
if (!m_DelayedMessages.empty ())
{
for (auto it :m_DelayedMessages)
m_Data.Send (it);
m_DelayedMessages.clear ();
}
if (m_PeerTest && (m_RemoteRouter && m_RemoteRouter->IsPeerTesting ()))
SendPeerTest ();
ScheduleTermination ();
}
void SSUSession::Failed ()
{
if (m_State != eSessionStateFailed)
{
m_State = eSessionStateFailed;
m_Server.DeleteSession (this); // delete this
}
}
void SSUSession::ScheduleTermination ()
{
m_Timer.cancel ();
m_Timer.expires_from_now (boost::posix_time::seconds(SSU_TERMINATION_TIMEOUT));
m_Timer.async_wait (boost::bind (&SSUSession::HandleTerminationTimer,
this, boost::asio::placeholders::error));
}
void SSUSession::HandleTerminationTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
LogPrint ("SSU no activity fo ", SSU_TERMINATION_TIMEOUT, " seconds");
Failed ();
}
}
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)
m_Data.Send (msg);
else
m_DelayedMessages.push_back (msg);
}
}
void SSUSession::ProcessData (uint8_t * buf, size_t len)
{
m_Data.ProcessMessage (buf, len);
}
void SSUSession::ProcessPeerTest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
uint8_t * buf1 = buf;
uint32_t nonce = be32toh (*(uint32_t *)buf);
buf += 4; // nonce
uint8_t size = *buf;
buf++; // size
uint8_t * address = (size == 4) ? buf : nullptr;
buf += size; // address
uint16_t port = *(uint16_t *)buf; // use it as is
buf += 2; // port
uint8_t * introKey = buf;
if (port && !address)
{
LogPrint ("Address of ", size, " bytes not supported");
return;
}
if (m_PeerTestNonces.count (nonce) > 0)
{
// existing test
if (m_PeerTest)
{
LogPrint ("SSU peer test from Bob. We are Alice");
m_PeerTestNonces.erase (nonce);
m_PeerTest = false;
}
else if (port)
{
LogPrint ("SSU peer test from Charlie. We are Bob");
// TODO: back to Alice
}
else
{
LogPrint ("SSU peer test from Alice. We are Charlie");
//SendPeerTest (nonce, be32toh (*(uint32_t *)address), be16toh (port), introKey); // to Alice
}
}
else
{
// new test
m_PeerTestNonces.insert (nonce);
if (port)
{
LogPrint ("SSU peer test from Bob. We are Charlie");
Send (PAYLOAD_TYPE_PEER_TEST, buf1, len); // back to Bob
SendPeerTest (nonce, be32toh (*(uint32_t *)address), be16toh (port), introKey); // to Alice
}
else
{
LogPrint ("SSU peer test from Alice. We are Bob");
// TODO: find Charlie
}
}
}
void SSUSession::SendPeerTest (uint32_t nonce, uint32_t address, uint16_t port, uint8_t * introKey)
{
uint8_t buf[80 + 18];
uint8_t iv[16];
uint8_t * payload = buf + sizeof (SSUHeader);
*(uint32_t *)payload = htobe32 (nonce);
payload += 4; // nonce
*payload = 4;
payload++; // size
*(uint32_t *)payload = htobe32 (address);
payload += 4; // address
*(uint16_t *)payload = htobe32 (port);
payload += 2; // port
memcpy (payload, introKey, 32); // intro key
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (iv, 16); // random iv
// encrypt message with specified intro key
FillHeaderAndEncrypt (PAYLOAD_TYPE_PEER_TEST, buf, 80, introKey, iv, introKey);
boost::asio::ip::udp::endpoint e (boost::asio::ip::address_v4 (address), port);
m_Server.Send (buf, 80, e);
}
void SSUSession::SendPeerTest ()
{
LogPrint ("SSU sending peer test");
auto address = i2p::context.GetRouterInfo ().GetSSUAddress ();
if (!address)
{
LogPrint ("SSU is not supported. Can't send peer test");
return;
}
auto introKey = address->key;
uint8_t buf[80 + 18];
uint8_t * payload = buf + sizeof (SSUHeader);
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
uint32_t nonce = 0;
rnd.GenerateWord32 (nonce);
m_PeerTestNonces.insert (nonce);
*(uint32_t *)payload = htobe32 (nonce);
payload += 4; // nonce
*payload = 4;
payload++; // size
memset (payload, 0, 6); // address and port always zero for Alice
payload += 6; // address and port
memcpy (payload, introKey, 32); // intro key
// encrypt message with session key
FillHeaderAndEncrypt (PAYLOAD_TYPE_PEER_TEST, buf, 80);
Send (buf, 80);
}
void SSUSession::SendSesionDestroyed ()
{
if (m_IsSessionKey)
{
uint8_t buf[48 + 18];
// encrypt message with session key
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_DESTROYED, buf, 48);
Send (buf, 48);
LogPrint ("SSU session destroyed sent");
}
}
void SSUSession::Send (uint8_t type, const uint8_t * payload, size_t len)
{
uint8_t buf[SSU_MTU + 18];
size_t msgSize = len + sizeof (SSUHeader);
if (msgSize > SSU_MTU)
{
LogPrint ("SSU payload size ", msgSize, " exceeds MTU");
return;
}
memcpy (buf + sizeof (SSUHeader), payload, len);
// encrypt message with session key
FillHeaderAndEncrypt (type, buf, msgSize);
Send (buf, msgSize);
}
void SSUSession::Send (const uint8_t * buf, size_t size)
{
m_NumSentBytes += size;
m_Server.Send (buf, size, m_RemoteEndpoint);
}
SSUServer::SSUServer (int port): m_Thread (nullptr), m_Work (m_Service),
m_Endpoint (boost::asio::ip::udp::v4 (), port), m_Socket (m_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 ()
{
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&SSUServer::Run, this));
m_Service.post (boost::bind (&SSUServer::Receive, this));
}
void SSUServer::Stop ()
{
DeleteAllSessions ();
m_IsRunning = false;
m_Service.stop ();
m_Socket.close ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = 0;
}
}
void SSUServer::Run ()
{
while (m_IsRunning)
{
try
{
m_Service.run ();
}
catch (std::exception& ex)
{
LogPrint ("SSU server: ", ex.what ());
}
}
}
void SSUServer::AddRelay (uint32_t tag, const boost::asio::ip::udp::endpoint& relay)
{
m_Relays[tag] = relay;
}
SSUSession * SSUServer::FindRelaySession (uint32_t tag)
{
auto it = m_Relays.find (tag);
if (it != m_Relays.end ())
return FindSession (it->second);
return nullptr;
}
void SSUServer::Send (const uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& to)
{
m_Socket.send_to (boost::asio::buffer (buf, len), to);
}
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)
{
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::FindSession (const i2p::data::RouterInfo * router)
{
if (!router) return nullptr;
auto address = router->GetSSUAddress ();
if (!address) return nullptr;
return FindSession (boost::asio::ip::udp::endpoint (address->host, address->port));
}
SSUSession * SSUServer::FindSession (const boost::asio::ip::udp::endpoint& e)
{
auto it = m_Sessions.find (e);
if (it != m_Sessions.end ())
return it->second;
else
return nullptr;
}
SSUSession * SSUServer::GetSession (const i2p::data::RouterInfo * router, bool peerTest)
{
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
session = new SSUSession (*this, remoteEndpoint, router, peerTest);
m_Sessions[remoteEndpoint] = session;
if (!router->UsesIntroducer ())
{
// connect directly
LogPrint ("Creating new SSU session to [", router->GetIdentHashAbbreviation (), "] ",
remoteEndpoint.address ().to_string (), ":", remoteEndpoint.port ());
session->Connect ();
}
else
{
// connect through introducer
int numIntroducers = address->introducers.size ();
if (numIntroducers > 0)
{
SSUSession * introducerSession = nullptr;
const i2p::data::RouterInfo::Introducer * introducer = nullptr;
// we might have a session to introducer already
for (int i = 0; i < numIntroducers; i++)
{
introducer = &(address->introducers[i]);
it = m_Sessions.find (boost::asio::ip::udp::endpoint (introducer->iHost, introducer->iPort));
if (it != m_Sessions.end ())
{
introducerSession = it->second;
break;
}
}
if (introducerSession) // session found
LogPrint ("Session to introducer already exists");
else // create new
{
LogPrint ("Creating new session to introducer");
introducer = &(address->introducers[0]); // TODO:
boost::asio::ip::udp::endpoint introducerEndpoint (introducer->iHost, introducer->iPort);
introducerSession = new SSUSession (*this, introducerEndpoint, router);
m_Sessions[introducerEndpoint] = introducerSession;
}
// introduce
LogPrint ("Introduce new SSU session to [", router->GetIdentHashAbbreviation (),
"] through introducer ", introducer->iHost, ":", introducer->iPort);
session->WaitForIntroduction ();
introducerSession->Introduce (introducer->iTag, introducer->iKey);
}
else
{
LogPrint ("Router is unreachable, but no introducers presented. Ignored");
m_Sessions.erase (remoteEndpoint);
delete session;
session = nullptr;
}
}
}
}
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 ();
}
}
}
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