i2pd/libi2pd/SSU2.cpp
Anatolii Cherednichenko 55534ea002 Reformat code
2022-08-30 02:11:28 +03:00

879 lines
42 KiB
C++

/*
* Copyright (c) 2022, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/
#include <random>
#include "Log.h"
#include "RouterContext.h"
#include "Transports.h"
#include "NetDb.hpp"
#include "Config.h"
#include "SSU2.h"
namespace i2p {
namespace transport {
SSU2Server::SSU2Server() :
RunnableServiceWithWork("SSU2"), m_ReceiveService("SSU2r"),
m_SocketV4(m_ReceiveService.GetService()), m_SocketV6(m_ReceiveService.GetService()),
m_AddressV4(boost::asio::ip::address_v4()), m_AddressV6(boost::asio::ip::address_v6()),
m_TerminationTimer(GetService()), m_ResendTimer(GetService()),
m_IntroducersUpdateTimer(GetService()), m_IntroducersUpdateTimerV6(GetService()),
m_IsPublished(true), m_IsSyncClockFromPeers(true) {
}
void SSU2Server::Start() {
if (!IsRunning()) {
StartIOService();
i2p::config::GetOption("ssu2.published", m_IsPublished);
i2p::config::GetOption("nettime.frompeers", m_IsSyncClockFromPeers);
bool found = false;
auto &addresses = i2p::context.GetRouterInfo().GetAddresses();
for (const auto &address: addresses) {
if (!address) continue;
if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2) {
auto port = address->port;
if (!port) {
uint16_t ssu2Port;
i2p::config::GetOption("ssu2.port", ssu2Port);
if (ssu2Port) port = ssu2Port;
else {
bool ssu;
i2p::config::GetOption("ssu", ssu);
uint16_t p;
i2p::config::GetOption("port", p);
if (p) port = ssu ? (p + 1) : p;
}
}
if (port) {
if (address->IsV4()) {
found = true;
OpenSocket(boost::asio::ip::udp::endpoint(m_AddressV4, port));
m_ReceiveService.GetService().post(
[this]() {
Receive(m_SocketV4);
});
ScheduleIntroducersUpdateTimer(); // wait for 30 seconds and decide if we need introducers
}
if (address->IsV6()) {
found = true;
OpenSocket(boost::asio::ip::udp::endpoint(m_AddressV6, port));
m_ReceiveService.GetService().post(
[this]() {
Receive(m_SocketV6);
});
ScheduleIntroducersUpdateTimerV6(); // wait for 30 seconds and decide if we need introducers
}
} else
LogPrint(eLogError, "SSU2: Can't start server because port not specified");
}
}
if (found)
m_ReceiveService.Start();
ScheduleTermination();
}
}
void SSU2Server::Stop() {
if (IsRunning()) {
m_TerminationTimer.cancel();
m_ResendTimer.cancel();
m_IntroducersUpdateTimer.cancel();
m_IntroducersUpdateTimerV6.cancel();
}
auto sessions = m_Sessions;
for (auto &it: sessions) {
it.second->RequestTermination(eSSU2TerminationReasonRouterShutdown);
it.second->Done();
}
if (context.SupportsV4() || context.SupportsV6())
m_ReceiveService.Stop();
m_SocketV4.close();
m_SocketV6.close();
StopIOService();
m_Sessions.clear();
m_SessionsByRouterHash.clear();
m_PendingOutgoingSessions.clear();
m_Relays.clear();
m_Introducers.clear();
m_IntroducersV6.clear();
}
void SSU2Server::SetLocalAddress(const boost::asio::ip::address &localAddress) {
if (localAddress.is_unspecified()) return;
if (localAddress.is_v4()) {
m_AddressV4 = localAddress;
int mtu = i2p::util::net::GetMTU(localAddress);
if (mtu < (int) SSU2_MIN_PACKET_SIZE) mtu = SSU2_MIN_PACKET_SIZE;
if (mtu > (int) SSU2_MAX_PACKET_SIZE) mtu = SSU2_MAX_PACKET_SIZE;
i2p::context.SetMTU(mtu, true);
} else if (localAddress.is_v6()) {
m_AddressV6 = localAddress;
int maxMTU = i2p::util::net::GetMaxMTU(localAddress.to_v6());
int mtu = i2p::util::net::GetMTU(localAddress);
if (mtu > maxMTU) mtu = maxMTU;
if (mtu < (int) SSU2_MIN_PACKET_SIZE) mtu = SSU2_MIN_PACKET_SIZE;
i2p::context.SetMTU(mtu, false);
}
}
bool SSU2Server::IsSupported(const boost::asio::ip::address &addr) const {
if (addr.is_v4()) {
if (m_SocketV4.is_open())
return true;
} else if (addr.is_v6()) {
if (m_SocketV6.is_open())
return true;
}
return false;
}
uint16_t SSU2Server::GetPort(bool v4) const {
boost::system::error_code ec;
boost::asio::ip::udp::endpoint ep = v4 ? m_SocketV4.local_endpoint(ec) : m_SocketV6.local_endpoint(ec);
if (ec) return 0;
return ep.port();
}
boost::asio::ip::udp::socket &SSU2Server::OpenSocket(const boost::asio::ip::udp::endpoint &localEndpoint) {
boost::asio::ip::udp::socket &socket = localEndpoint.address().is_v6() ? m_SocketV6 : m_SocketV4;
try {
socket.open(localEndpoint.protocol());
if (localEndpoint.address().is_v6())
socket.set_option(boost::asio::ip::v6_only(true));
socket.set_option(boost::asio::socket_base::receive_buffer_size(SSU2_SOCKET_RECEIVE_BUFFER_SIZE));
socket.set_option(boost::asio::socket_base::send_buffer_size(SSU2_SOCKET_SEND_BUFFER_SIZE));
socket.bind(localEndpoint);
LogPrint(eLogInfo, "SSU2: Start listening on ", localEndpoint);
}
catch (std::exception &ex) {
LogPrint(eLogError, "SSU2: Failed to bind to ", localEndpoint, ": ", ex.what());
ThrowFatal("Unable to start SSU2 transport on ", localEndpoint, ": ", ex.what());
}
return socket;
}
void SSU2Server::Receive(boost::asio::ip::udp::socket &socket) {
Packet *packet = m_PacketsPool.AcquireMt();
socket.async_receive_from(boost::asio::buffer(packet->buf, SSU2_MAX_PACKET_SIZE), packet->from,
std::bind(&SSU2Server::HandleReceivedFrom, this, std::placeholders::_1,
std::placeholders::_2, packet, std::ref(socket)));
}
void SSU2Server::HandleReceivedFrom(const boost::system::error_code &ecode, size_t bytes_transferred,
Packet *packet, boost::asio::ip::udp::socket &socket) {
if (!ecode) {
i2p::transport::transports.UpdateReceivedBytes(bytes_transferred);
packet->len = bytes_transferred;
boost::system::error_code ec;
size_t moreBytes = socket.available(ec);
if (!ec && moreBytes) {
std::vector<Packet *> packets;
packets.push_back(packet);
while (moreBytes && packets.size() < 32) {
packet = m_PacketsPool.AcquireMt();
packet->len = socket.receive_from(boost::asio::buffer(packet->buf, SSU2_MAX_PACKET_SIZE),
packet->from, 0, ec);
if (!ec) {
i2p::transport::transports.UpdateReceivedBytes(packet->len);
packets.push_back(packet);
moreBytes = socket.available(ec);
if (ec) break;
} else {
LogPrint(eLogError, "SSU2: receive_from error: code ", ec.value(), ": ", ec.message());
m_PacketsPool.ReleaseMt(packet);
break;
}
}
GetService().post(std::bind(&SSU2Server::HandleReceivedPackets, this, packets));
} else
GetService().post(std::bind(&SSU2Server::HandleReceivedPacket, this, packet));
Receive(socket);
} else {
m_PacketsPool.ReleaseMt(packet);
if (ecode != boost::asio::error::operation_aborted) {
LogPrint(eLogError, "SSU2: Receive error: code ", ecode.value(), ": ", ecode.message());
auto ep = socket.local_endpoint();
socket.close();
OpenSocket(ep);
Receive(socket);
}
}
}
void SSU2Server::HandleReceivedPacket(Packet *packet) {
if (packet) {
ProcessNextPacket(packet->buf, packet->len, packet->from);
m_PacketsPool.ReleaseMt(packet);
if (m_LastSession && m_LastSession->GetState() != eSSU2SessionStateTerminated)
m_LastSession->FlushData();
}
}
void SSU2Server::HandleReceivedPackets(std::vector<Packet *> packets) {
for (auto &packet: packets)
ProcessNextPacket(packet->buf, packet->len, packet->from);
m_PacketsPool.ReleaseMt(packets);
if (m_LastSession && m_LastSession->GetState() != eSSU2SessionStateTerminated)
m_LastSession->FlushData();
}
void SSU2Server::AddSession(std::shared_ptr<SSU2Session> session) {
if (session) {
m_Sessions.emplace(session->GetConnID(), session);
AddSessionByRouterHash(session);
}
}
void SSU2Server::RemoveSession(uint64_t connID) {
auto it = m_Sessions.find(connID);
if (it != m_Sessions.end()) {
auto ident = it->second->GetRemoteIdentity();
if (ident)
m_SessionsByRouterHash.erase(ident->GetIdentHash());
if (m_LastSession == it->second)
m_LastSession = nullptr;
m_Sessions.erase(it);
}
}
void SSU2Server::AddSessionByRouterHash(std::shared_ptr<SSU2Session> session) {
if (session) {
auto ident = session->GetRemoteIdentity();
if (ident) {
auto ret = m_SessionsByRouterHash.emplace(ident->GetIdentHash(), session);
if (!ret.second) {
// session already exists
LogPrint(eLogWarning, "SSU2: Session to ", ident->GetIdentHash().ToBase64(), " already exists");
// terminate existing
GetService().post(std::bind(&SSU2Session::RequestTermination, ret.first->second,
eSSU2TerminationReasonReplacedByNewSession));
// update session
ret.first->second = session;
}
}
}
}
bool SSU2Server::AddPendingOutgoingSession(std::shared_ptr<SSU2Session> session) {
if (!session) return false;
return m_PendingOutgoingSessions.emplace(session->GetRemoteEndpoint(), session).second;
}
std::shared_ptr<SSU2Session> SSU2Server::FindSession(const i2p::data::IdentHash &ident) const {
auto it = m_SessionsByRouterHash.find(ident);
if (it != m_SessionsByRouterHash.end())
return it->second;
return nullptr;
}
std::shared_ptr<SSU2Session>
SSU2Server::FindPendingOutgoingSession(const boost::asio::ip::udp::endpoint &ep) const {
auto it = m_PendingOutgoingSessions.find(ep);
if (it != m_PendingOutgoingSessions.end())
return it->second;
return nullptr;
}
void SSU2Server::RemovePendingOutgoingSession(const boost::asio::ip::udp::endpoint &ep) {
m_PendingOutgoingSessions.erase(ep);
}
std::shared_ptr<SSU2Session> SSU2Server::GetRandomSession(
i2p::data::RouterInfo::CompatibleTransports remoteTransports,
const i2p::data::IdentHash &excluded) const {
if (m_Sessions.empty()) return nullptr;
uint16_t ind;
RAND_bytes((uint8_t * ) & ind, sizeof(ind));
ind %= m_Sessions.size();
auto it = m_Sessions.begin();
std::advance(it, ind);
while (it != m_Sessions.end()) {
if ((it->second->GetRemoteTransports() & remoteTransports) &&
it->second->GetRemoteIdentity()->GetIdentHash() != excluded)
return it->second;
it++;
}
// not found, try from begining
it = m_Sessions.begin();
while (it != m_Sessions.end() && ind) {
if ((it->second->GetRemoteTransports() & remoteTransports) &&
it->second->GetRemoteIdentity()->GetIdentHash() != excluded)
return it->second;
it++;
ind--;
}
return nullptr;
}
void SSU2Server::AddRelay(uint32_t tag, std::shared_ptr<SSU2Session> relay) {
m_Relays.emplace(tag, relay);
}
void SSU2Server::RemoveRelay(uint32_t tag) {
m_Relays.erase(tag);
}
std::shared_ptr<SSU2Session> SSU2Server::FindRelaySession(uint32_t tag) {
auto it = m_Relays.find(tag);
if (it != m_Relays.end()) {
if (it->second->IsEstablished())
return it->second;
else
m_Relays.erase(it);
}
return nullptr;
}
void
SSU2Server::ProcessNextPacket(uint8_t *buf, size_t len, const boost::asio::ip::udp::endpoint &senderEndpoint) {
if (len < 24) return;
uint64_t connID;
memcpy(&connID, buf, 8);
connID ^= CreateHeaderMask(i2p::context.GetSSU2IntroKey(), buf + (len - 24));
if (!m_LastSession || m_LastSession->GetConnID() != connID) {
if (m_LastSession) m_LastSession->FlushData();
auto it = m_Sessions.find(connID);
if (it != m_Sessions.end())
m_LastSession = it->second;
else
m_LastSession = nullptr;
}
if (m_LastSession) {
switch (m_LastSession->GetState()) {
case eSSU2SessionStateEstablished:
case eSSU2SessionStateSessionConfirmedSent:
m_LastSession->ProcessData(buf, len);
break;
case eSSU2SessionStateSessionCreatedSent:
if (!m_LastSession->ProcessSessionConfirmed(buf, len)) {
m_LastSession->Done();
m_LastSession = nullptr;
}
break;
case eSSU2SessionStateIntroduced:
if (m_LastSession->GetRemoteEndpoint().address().is_unspecified())
m_LastSession->SetRemoteEndpoint(senderEndpoint);
if (m_LastSession->GetRemoteEndpoint() == senderEndpoint)
m_LastSession->ProcessHolePunch(buf, len);
else {
LogPrint(eLogWarning, "SSU2: HolePunch endpoint ", senderEndpoint,
" doesn't match RelayResponse ", m_LastSession->GetRemoteEndpoint());
m_LastSession->Done();
m_LastSession = nullptr;
}
break;
case eSSU2SessionStatePeerTest:
m_LastSession->SetRemoteEndpoint(senderEndpoint);
m_LastSession->ProcessPeerTest(buf, len);
break;
case eSSU2SessionStateClosing:
m_LastSession->ProcessData(buf, len); // we might receive termintaion block
if (m_LastSession && m_LastSession->GetState() != eSSU2SessionStateTerminated)
m_LastSession->RequestTermination(
eSSU2TerminationReasonIdleTimeout); // send termination again
break;
case eSSU2SessionStateTerminated:
m_LastSession = nullptr;
break;
default:
LogPrint(eLogWarning, "SSU2: Invalid session state ", (int) m_LastSession->GetState());
}
} else {
// check pending sessions if it's SessionCreated or Retry
auto it1 = m_PendingOutgoingSessions.find(senderEndpoint);
if (it1 != m_PendingOutgoingSessions.end()) {
if (it1->second->GetState() == eSSU2SessionStateSessionRequestSent &&
it1->second->ProcessSessionCreated(buf, len))
m_PendingOutgoingSessions.erase(it1); // we are done with that endpoint
else
it1->second->ProcessRetry(buf, len);
} else {
// assume new incoming session
auto session = std::make_shared<SSU2Session>(*this);
session->SetRemoteEndpoint(senderEndpoint);
session->ProcessFirstIncomingMessage(connID, buf, len);
}
}
}
void SSU2Server::Send(const uint8_t *header, size_t headerLen, const uint8_t *payload, size_t payloadLen,
const boost::asio::ip::udp::endpoint &to) {
std::vector<boost::asio::const_buffer> bufs
{
boost::asio::buffer(header, headerLen),
boost::asio::buffer(payload, payloadLen)
};
boost::system::error_code ec;
if (to.address().is_v6())
m_SocketV6.send_to(bufs, to, 0, ec);
else
m_SocketV4.send_to(bufs, to, 0, ec);
if (!ec)
i2p::transport::transports.UpdateSentBytes(headerLen + payloadLen);
else
LogPrint(eLogError, "SSU2: Send exception: ", ec.message(), " to ", to);
}
void SSU2Server::Send(const uint8_t *header, size_t headerLen, const uint8_t *headerX, size_t headerXLen,
const uint8_t *payload, size_t payloadLen, const boost::asio::ip::udp::endpoint &to) {
std::vector<boost::asio::const_buffer> bufs
{
boost::asio::buffer(header, headerLen),
boost::asio::buffer(headerX, headerXLen),
boost::asio::buffer(payload, payloadLen)
};
boost::system::error_code ec;
if (to.address().is_v6())
m_SocketV6.send_to(bufs, to, 0, ec);
else
m_SocketV4.send_to(bufs, to, 0, ec);
if (!ec)
i2p::transport::transports.UpdateSentBytes(headerLen + headerXLen + payloadLen);
else
LogPrint(eLogError, "SSU2: Send exception: ", ec.message(), " to ", to);
}
bool SSU2Server::CreateSession(std::shared_ptr<const i2p::data::RouterInfo> router,
std::shared_ptr<const i2p::data::RouterInfo::Address> address, bool peerTest) {
if (router && address) {
// check if no session
auto it = m_SessionsByRouterHash.find(router->GetIdentHash());
if (it != m_SessionsByRouterHash.end()) {
// session with router found, trying to send peer test if requested
if (peerTest && it->second->IsEstablished()) {
auto session = it->second;
GetService().post([session]() { session->SendPeerTest(); });
}
return false;
}
// check is no pending session
bool isValidEndpoint = !address->host.is_unspecified() && address->port;
if (isValidEndpoint) {
if (i2p::util::net::IsInReservedRange(address->host)) return false;
auto s = FindPendingOutgoingSession(boost::asio::ip::udp::endpoint(address->host, address->port));
if (s) {
if (peerTest) {
// if peer test requested add it to the list for pending session
auto onEstablished = s->GetOnEstablished();
if (onEstablished)
s->SetOnEstablished([s, onEstablished]() {
onEstablished();
s->SendPeerTest();
});
else
s->SetOnEstablished([s]() { s->SendPeerTest(); });
}
return false;
}
}
auto session = std::make_shared<SSU2Session>(*this, router, address);
if (peerTest)
session->SetOnEstablished([session]() { session->SendPeerTest(); });
if (address->UsesIntroducer())
GetService().post(std::bind(&SSU2Server::ConnectThroughIntroducer, this, session));
else if (isValidEndpoint) // we can't connect without endpoint
GetService().post([session]() { session->Connect(); });
else
return false;
} else
return false;
return true;
}
void SSU2Server::ConnectThroughIntroducer(std::shared_ptr<SSU2Session> session) {
if (!session) return;
auto address = session->GetAddress();
if (!address) return;
session->WaitForIntroduction();
// try to find existing session first
for (auto &it: address->ssu->introducers) {
auto it1 = m_SessionsByRouterHash.find(it.iKey);
if (it1 != m_SessionsByRouterHash.end()) {
it1->second->Introduce(session, it.iTag);
return;
}
}
// we have to start a new session to an introducer
auto ts = i2p::util::GetSecondsSinceEpoch();
std::shared_ptr<i2p::data::RouterInfo> r;
uint32_t relayTag = 0;
if (!address->ssu->introducers.empty()) {
std::vector<int> indicies;
for (int i = 0; i < (int) address->ssu->introducers.size(); i++) indicies.push_back(i);
if (indicies.size() > 1)
std::shuffle(indicies.begin(), indicies.end(), std::mt19937(std::random_device()()));
for (auto i: indicies) {
const auto &introducer = address->ssu->introducers[indicies[i]];
if (introducer.iTag && ts < introducer.iExp) {
r = i2p::data::netdb.FindRouter(introducer.iKey);
if (r && r->IsReachableFrom(i2p::context.GetRouterInfo())) {
relayTag = introducer.iTag;
if (relayTag) break;
}
}
}
}
if (r) {
if (relayTag) {
// introducer and tag found connect to it through SSU2
auto addr = address->IsV6() ? r->GetSSU2V6Address() : r->GetSSU2V4Address();
if (addr) {
bool isValidEndpoint = !addr->host.is_unspecified() && addr->port &&
!i2p::util::net::IsInReservedRange(addr->host);
if (isValidEndpoint) {
auto s = FindPendingOutgoingSession(boost::asio::ip::udp::endpoint(addr->host, addr->port));
if (!s) {
s = std::make_shared<SSU2Session>(*this, r, addr);
s->SetOnEstablished([session, s, relayTag]() { s->Introduce(session, relayTag); });
s->Connect();
} else {
auto onEstablished = s->GetOnEstablished();
if (onEstablished)
s->SetOnEstablished([session, s, relayTag, onEstablished]() {
onEstablished();
s->Introduce(session, relayTag);
});
else
s->SetOnEstablished([session, s, relayTag]() { s->Introduce(session, relayTag); });
}
}
}
}
} else {
// introducers not found, try to request them
for (auto &it: address->ssu->introducers)
if (it.iTag && ts < it.iExp)
i2p::data::netdb.RequestDestination(it.iKey);
}
}
bool SSU2Server::StartPeerTest(std::shared_ptr<const i2p::data::RouterInfo> router, bool v4) {
if (!router) return false;
auto addr = v4 ? router->GetSSU2V4Address() : router->GetSSU2V6Address();
if (!addr) return false;
auto it = m_SessionsByRouterHash.find(router->GetIdentHash());
if (it != m_SessionsByRouterHash.end()) {
auto s = it->second;
if (it->second->IsEstablished())
GetService().post([s]() { s->SendPeerTest(); });
else
s->SetOnEstablished([s]() { s->SendPeerTest(); });
return true;
} else
CreateSession(router, addr, true);
return true;
}
void SSU2Server::ScheduleTermination() {
m_TerminationTimer.expires_from_now(boost::posix_time::seconds(SSU2_TERMINATION_CHECK_TIMEOUT));
m_TerminationTimer.async_wait(std::bind(&SSU2Server::HandleTerminationTimer,
this, std::placeholders::_1));
}
void SSU2Server::HandleTerminationTimer(const boost::system::error_code &ecode) {
if (ecode != boost::asio::error::operation_aborted) {
auto ts = i2p::util::GetSecondsSinceEpoch();
for (auto it = m_PendingOutgoingSessions.begin(); it != m_PendingOutgoingSessions.end();) {
if (it->second->IsTerminationTimeoutExpired(ts)) {
//it->second->Terminate ();
it = m_PendingOutgoingSessions.erase(it);
} else
it++;
}
for (auto it: m_Sessions) {
auto state = it.second->GetState();
if (state == eSSU2SessionStateTerminated || state == eSSU2SessionStateClosing)
it.second->Done();
else if (it.second->IsTerminationTimeoutExpired(ts)) {
if (it.second->IsEstablished())
it.second->RequestTermination(eSSU2TerminationReasonIdleTimeout);
else
it.second->Done();
} else
it.second->CleanUp(ts);
}
for (auto it = m_SessionsByRouterHash.begin(); it != m_SessionsByRouterHash.begin();) {
if (it->second && it->second->GetState() == eSSU2SessionStateTerminated)
it = m_SessionsByRouterHash.erase(it);
else
it++;
}
for (auto it = m_Relays.begin(); it != m_Relays.begin();) {
if (it->second && it->second->GetState() == eSSU2SessionStateTerminated)
it = m_Relays.erase(it);
else
it++;
}
for (auto it = m_IncomingTokens.begin(); it != m_IncomingTokens.end();) {
if (ts > it->second.second)
it = m_IncomingTokens.erase(it);
else
it++;
}
for (auto it = m_OutgoingTokens.begin(); it != m_OutgoingTokens.end();) {
if (ts > it->second.second)
it = m_OutgoingTokens.erase(it);
else
it++;
}
m_PacketsPool.CleanUpMt();
m_SentPacketsPool.CleanUp();
ScheduleTermination();
}
}
void SSU2Server::ScheduleResend() {
m_ResendTimer.expires_from_now(boost::posix_time::milliseconds(SSU2_RESEND_CHECK_TIMEOUT));
m_ResendTimer.async_wait(std::bind(&SSU2Server::HandleResendTimer,
this, std::placeholders::_1));
}
void SSU2Server::HandleResendTimer(const boost::system::error_code &ecode) {
if (ecode != boost::asio::error::operation_aborted) {
auto ts = i2p::util::GetMillisecondsSinceEpoch();
for (auto it: m_Sessions)
it.second->Resend(ts);
for (auto it: m_PendingOutgoingSessions)
it.second->Resend(ts);
ScheduleResend();
}
}
void SSU2Server::UpdateOutgoingToken(const boost::asio::ip::udp::endpoint &ep, uint64_t token, uint32_t exp) {
m_OutgoingTokens[ep] = {token, exp};
}
uint64_t SSU2Server::FindOutgoingToken(const boost::asio::ip::udp::endpoint &ep) const {
auto it = m_OutgoingTokens.find(ep);
if (it != m_OutgoingTokens.end()) {
if (i2p::util::GetSecondsSinceEpoch() + SSU2_TOKEN_EXPIRATION_THRESHOLD > it->second.second)
return 0; // token expired
return it->second.first;
}
return 0;
}
uint64_t SSU2Server::GetIncomingToken(const boost::asio::ip::udp::endpoint &ep) {
auto it = m_IncomingTokens.find(ep);
if (it != m_IncomingTokens.end())
return it->second.first;
uint64_t token;
RAND_bytes((uint8_t * ) & token, 8);
m_IncomingTokens.emplace(ep, std::make_pair(token, i2p::util::GetSecondsSinceEpoch() +
SSU2_TOKEN_EXPIRATION_TIMEOUT));
return token;
}
std::pair<uint64_t, uint32_t> SSU2Server::NewIncomingToken(const boost::asio::ip::udp::endpoint &ep) {
m_IncomingTokens.erase(ep); // drop previous
uint64_t token;
RAND_bytes((uint8_t * ) & token, 8);
auto ret = std::make_pair(token, i2p::util::GetSecondsSinceEpoch() + SSU2_NEXT_TOKEN_EXPIRATION_TIMEOUT);
m_IncomingTokens.emplace(ep, ret);
return ret;
}
std::list<std::shared_ptr<SSU2Session> > SSU2Server::FindIntroducers(int maxNumIntroducers,
bool v4,
const std::set<i2p::data::IdentHash> &excluded) const {
std::list<std::shared_ptr<SSU2Session> > ret;
for (const auto &s: m_Sessions) {
if (s.second->IsEstablished() && (s.second->GetRelayTag() && s.second->IsOutgoing()) &&
!excluded.count(s.second->GetRemoteIdentity()->GetIdentHash()) &&
((v4 && (s.second->GetRemoteTransports() & i2p::data::RouterInfo::eSSU2V4)) ||
(!v4 && (s.second->GetRemoteTransports() & i2p::data::RouterInfo::eSSU2V6))))
ret.push_back(s.second);
}
if ((int) ret.size() > maxNumIntroducers) {
// shink ret randomly
int sz = ret.size() - maxNumIntroducers;
for (int i = 0; i < sz; i++) {
auto ind = rand() % ret.size();
auto it = ret.begin();
std::advance(it, ind);
ret.erase(it);
}
}
return ret;
}
void SSU2Server::UpdateIntroducers(bool v4) {
uint32_t ts = i2p::util::GetSecondsSinceEpoch();
std::list<i2p::data::IdentHash> newList;
auto &introducers = v4 ? m_Introducers : m_IntroducersV6;
std::set<i2p::data::IdentHash> excluded;
for (const auto &it: introducers) {
std::shared_ptr<SSU2Session> session;
auto it1 = m_SessionsByRouterHash.find(it);
if (it1 != m_SessionsByRouterHash.end()) {
session = it1->second;
excluded.insert(it);
}
if (session && session->IsEstablished()) {
if (ts < session->GetCreationTime() + SSU2_TO_INTRODUCER_SESSION_EXPIRATION)
session->SendKeepAlive();
if (ts < session->GetCreationTime() + SSU2_TO_INTRODUCER_SESSION_DURATION)
newList.push_back(it);
else
session = nullptr;
}
if (!session)
i2p::context.RemoveSSU2Introducer(it, v4);
}
if (newList.size() < SSU2_MAX_NUM_INTRODUCERS) {
auto sessions = FindIntroducers(SSU2_MAX_NUM_INTRODUCERS - newList.size(), v4, excluded);
if (sessions.empty() && !introducers.empty()) {
// bump creation time for previous introducers if no new sessions found
LogPrint(eLogDebug, "SSU2: No new introducers found. Trying to reuse existing");
for (auto &it: introducers) {
auto it1 = m_SessionsByRouterHash.find(it);
if (it1 != m_SessionsByRouterHash.end()) {
auto session = it1->second;
if (session->IsEstablished()) {
session->SetCreationTime(
session->GetCreationTime() + SSU2_TO_INTRODUCER_SESSION_DURATION);
if (std::find(newList.begin(), newList.end(), it) == newList.end()) {
newList.push_back(it);
sessions.push_back(session);
}
}
}
}
}
for (const auto &it: sessions) {
i2p::data::RouterInfo::Introducer introducer;
introducer.iTag = it->GetRelayTag();
introducer.iKey = it->GetRemoteIdentity()->GetIdentHash();
introducer.iExp = it->GetCreationTime() + SSU2_TO_INTRODUCER_SESSION_EXPIRATION;
excluded.insert(it->GetRemoteIdentity()->GetIdentHash());
if (i2p::context.AddSSU2Introducer(introducer, v4)) {
LogPrint(eLogDebug, "SSU2: Introducer added ", it->GetRelayTag(), " at ",
i2p::data::GetIdentHashAbbreviation(it->GetRemoteIdentity()->GetIdentHash()));
newList.push_back(it->GetRemoteIdentity()->GetIdentHash());
if (newList.size() >= SSU2_MAX_NUM_INTRODUCERS) break;
}
}
}
introducers = newList;
if (introducers.size() < SSU2_MAX_NUM_INTRODUCERS) {
for (auto i = introducers.size(); i < SSU2_MAX_NUM_INTRODUCERS; i++) {
auto introducer = i2p::data::netdb.GetRandomSSU2Introducer(v4, excluded);
if (introducer) {
auto address = v4 ? introducer->GetSSU2V4Address() : introducer->GetSSU2V6Address();
if (address) {
CreateSession(introducer, address);
excluded.insert(introducer->GetIdentHash());
}
} else {
LogPrint(eLogDebug, "SSU2: Can't find more introducers");
break;
}
}
}
}
void SSU2Server::ScheduleIntroducersUpdateTimer() {
if (m_IsPublished) {
m_IntroducersUpdateTimer.expires_from_now(boost::posix_time::seconds(SSU2_KEEP_ALIVE_INTERVAL));
m_IntroducersUpdateTimer.async_wait(std::bind(&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, true));
}
}
void SSU2Server::RescheduleIntroducersUpdateTimer() {
if (m_IsPublished) {
m_IntroducersUpdateTimer.cancel();
i2p::context.ClearSSU2Introducers(true);
m_Introducers.clear();
m_IntroducersUpdateTimer.expires_from_now(boost::posix_time::seconds(SSU2_KEEP_ALIVE_INTERVAL / 2));
m_IntroducersUpdateTimer.async_wait(std::bind(&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, true));
}
}
void SSU2Server::ScheduleIntroducersUpdateTimerV6() {
if (m_IsPublished) {
m_IntroducersUpdateTimerV6.expires_from_now(boost::posix_time::seconds(SSU2_KEEP_ALIVE_INTERVAL));
m_IntroducersUpdateTimerV6.async_wait(std::bind(&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, false));
}
}
void SSU2Server::RescheduleIntroducersUpdateTimerV6() {
if (m_IsPublished) {
m_IntroducersUpdateTimerV6.cancel();
i2p::context.ClearSSU2Introducers(false);
m_IntroducersV6.clear();
m_IntroducersUpdateTimerV6.expires_from_now(boost::posix_time::seconds(SSU2_KEEP_ALIVE_INTERVAL / 2));
m_IntroducersUpdateTimerV6.async_wait(std::bind(&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, false));
}
}
void SSU2Server::HandleIntroducersUpdateTimer(const boost::system::error_code &ecode, bool v4) {
if (ecode != boost::asio::error::operation_aborted) {
// timeout expired
if (v4) {
if (i2p::context.GetStatus() == eRouterStatusTesting) {
// we still don't know if we need introducers
ScheduleIntroducersUpdateTimer();
return;
}
if (i2p::context.GetStatus() != eRouterStatusFirewalled) {
// we don't need introducers
i2p::context.ClearSSU2Introducers(true);
m_Introducers.clear();
return;
}
// we are firewalled
auto addr = i2p::context.GetRouterInfo().GetSSU2V4Address();
if (addr && addr->ssu && addr->ssu->introducers.empty())
i2p::context.SetUnreachableSSU2(true, false); // v4
UpdateIntroducers(true);
ScheduleIntroducersUpdateTimer();
} else {
if (i2p::context.GetStatusV6() == eRouterStatusTesting) {
// we still don't know if we need introducers
ScheduleIntroducersUpdateTimerV6();
return;
}
if (i2p::context.GetStatusV6() != eRouterStatusFirewalled) {
// we don't need introducers
i2p::context.ClearSSU2Introducers(false);
m_IntroducersV6.clear();
return;
}
// we are firewalled
auto addr = i2p::context.GetRouterInfo().GetSSU2V6Address();
if (addr && addr->ssu && addr->ssu->introducers.empty())
i2p::context.SetUnreachableSSU2(false, true); // v6
UpdateIntroducers(false);
ScheduleIntroducersUpdateTimerV6();
}
}
}
}
}