I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2013-2016, 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 <string.h>
#include <stdlib.h>
#include <openssl/rand.h>
#include "I2PEndian.h"
#include "Log.h"
#include "Timestamp.h"
#include "LeaseSet.h"
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#include "ClientContext.h"
#include "Transports.h"
#include "Signature.h"
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#include "I2CP.h"
namespace i2p
{
namespace client
{
I2CPDestination::I2CPDestination (I2CPSession& owner, std::shared_ptr<const i2p::data::IdentityEx> identity, bool isPublic, const std::map<std::string, std::string>& params):
LeaseSetDestination (isPublic, &params), m_Owner (owner), m_Identity (identity)
{
}
void I2CPDestination::SetEncryptionPrivateKey (const uint8_t * key)
{
memcpy (m_EncryptionPrivateKey, key, 256);
}
void I2CPDestination::HandleDataMessage (const uint8_t * buf, size_t len)
{
uint32_t length = bufbe32toh (buf);
if (length > len - 4) length = len - 4;
m_Owner.SendMessagePayloadMessage (buf + 4, length);
}
void I2CPDestination::CreateNewLeaseSet (std::vector<std::shared_ptr<i2p::tunnel::InboundTunnel> > tunnels)
{
i2p::data::LocalLeaseSet ls (m_Identity, m_EncryptionPrivateKey, tunnels); // we don't care about encryption key
m_LeaseSetExpirationTime = ls.GetExpirationTime ();
uint8_t * leases = ls.GetLeases ();
leases[-1] = tunnels.size ();
htobe16buf (leases - 3, m_Owner.GetSessionID ());
size_t l = 2/*sessionID*/ + 1/*num leases*/ + i2p::data::LEASE_SIZE*tunnels.size ();
m_Owner.SendI2CPMessage (I2CP_REQUEST_VARIABLE_LEASESET_MESSAGE, leases - 3, l);
}
void I2CPDestination::LeaseSetCreated (const uint8_t * buf, size_t len)
{
auto ls = new i2p::data::LocalLeaseSet (m_Identity, buf, len);
ls->SetExpirationTime (m_LeaseSetExpirationTime);
SetLeaseSet (ls);
}
void I2CPDestination::SendMsgTo (const uint8_t * payload, size_t len, const i2p::data::IdentHash& ident, uint32_t nonce)
{
auto msg = NewI2NPMessage ();
uint8_t * buf = msg->GetPayload ();
htobe32buf (buf, len);
memcpy (buf + 4, payload, len);
msg->len += len + 4;
msg->FillI2NPMessageHeader (eI2NPData);
auto remote = FindLeaseSet (ident);
if (remote)
GetService ().post (std::bind (&I2CPDestination::SendMsg, GetSharedFromThis (), msg, remote));
else
{
auto s = GetSharedFromThis ();
RequestDestination (ident,
[s, msg, nonce](std::shared_ptr<i2p::data::LeaseSet> ls)
{
if (ls)
{
bool sent = s->SendMsg (msg, ls);
s->m_Owner.SendMessageStatusMessage (nonce, sent ? eI2CPMessageStatusGuaranteedSuccess : eI2CPMessageStatusGuaranteedFailure);
}
else
s->m_Owner.SendMessageStatusMessage (nonce, eI2CPMessageStatusNoLeaseSet);
});
}
}
bool I2CPDestination::SendMsg (std::shared_ptr<I2NPMessage> msg, std::shared_ptr<const i2p::data::LeaseSet> remote)
{
auto outboundTunnel = GetTunnelPool ()->GetNextOutboundTunnel ();
auto leases = remote->GetNonExpiredLeases ();
if (!leases.empty () && outboundTunnel)
{
std::vector<i2p::tunnel::TunnelMessageBlock> msgs;
uint32_t i = rand () % leases.size ();
auto garlic = WrapMessage (remote, msg, true);
msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
leases[i]->tunnelGateway, leases[i]->tunnelID,
garlic
});
outboundTunnel->SendTunnelDataMsg (msgs);
return true;
}
else
{
if (outboundTunnel)
LogPrint (eLogWarning, "I2CP: Failed to send message. All leases expired");
else
LogPrint (eLogWarning, "I2CP: Failed to send message. No outbound tunnels");
return false;
}
}
I2CPSession::I2CPSession (I2CPServer& owner, std::shared_ptr<boost::asio::ip::tcp::socket> socket):
m_Owner (owner), m_Socket (socket),
m_NextMessage (nullptr), m_NextMessageLen (0), m_NextMessageOffset (0),
m_MessageID (0)
{
RAND_bytes ((uint8_t *)&m_SessionID, 2);
}
I2CPSession::~I2CPSession ()
{
delete[] m_NextMessage;
}
void I2CPSession::Start ()
{
ReadProtocolByte ();
}
void I2CPSession::Stop ()
{
}
void I2CPSession::ReadProtocolByte ()
{
if (m_Socket)
{
auto s = shared_from_this ();
m_Socket->async_read_some (boost::asio::buffer (m_Buffer, 1),
[s](const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (!ecode && bytes_transferred > 0 && s->m_Buffer[0] == I2CP_PROTOCOL_BYTE)
s->Receive ();
else
s->Terminate ();
});
}
}
void I2CPSession::Receive ()
{
m_Socket->async_read_some (boost::asio::buffer (m_Buffer, I2CP_SESSION_BUFFER_SIZE),
std::bind (&I2CPSession::HandleReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void I2CPSession::HandleReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
Terminate ();
else
{
size_t offset = 0; // from m_Buffer
if (m_NextMessage)
{
if (m_NextMessageOffset + bytes_transferred <= m_NextMessageLen)
{
memcpy (m_NextMessage + m_NextMessageOffset, m_Buffer, bytes_transferred);
m_NextMessageOffset += bytes_transferred;
offset = bytes_transferred;
}
else
{
// m_NextMessage complete
offset = m_NextMessageLen - m_NextMessageOffset;
memcpy (m_NextMessage + m_NextMessageOffset, m_Buffer, offset);
HandleNextMessage (m_NextMessage);
delete[] m_NextMessage;
m_NextMessage = nullptr;
}
}
while (offset < bytes_transferred)
{
auto msgLen = bufbe32toh (m_Buffer + offset + I2CP_HEADER_LENGTH_OFFSET) + I2CP_HEADER_SIZE;
if (msgLen > 0xFFFF) // 64K
{
LogPrint (eLogError, "I2CP: message length ", msgLen, " exceeds 64K. Terminated");
Terminate ();
return;
}
if (msgLen <= bytes_transferred - offset)
{
HandleNextMessage (m_Buffer + offset);
offset += msgLen;
}
else
{
m_NextMessageLen = msgLen;
m_NextMessageOffset = bytes_transferred - offset;
m_NextMessage = new uint8_t[m_NextMessageLen];
memcpy (m_NextMessage, m_Buffer + offset, m_NextMessageOffset);
offset = bytes_transferred;
}
}
Receive ();
}
}
void I2CPSession::HandleNextMessage (const uint8_t * buf)
{
auto handler = m_Owner.GetMessagesHandlers ()[buf[I2CP_HEADER_TYPE_OFFSET]];
if (handler)
(this->*handler)(buf + I2CP_HEADER_SIZE, bufbe32toh (buf + I2CP_HEADER_LENGTH_OFFSET));
else
LogPrint (eLogError, "I2CP: Unknown I2CP messsage ", (int)buf[I2CP_HEADER_TYPE_OFFSET]);
}
void I2CPSession::Terminate ()
{
if (m_Destination)
{
m_Destination->Stop ();
m_Destination = nullptr;
}
if (m_Socket)
{
m_Socket->close ();
m_Socket = nullptr;
}
m_Owner.RemoveSession (GetSessionID ());
}
void I2CPSession::SendI2CPMessage (uint8_t type, const uint8_t * payload, size_t len)
{
auto l = len + I2CP_HEADER_SIZE;
uint8_t * buf = new uint8_t[l];
htobe32buf (buf + I2CP_HEADER_LENGTH_OFFSET, len);
buf[I2CP_HEADER_TYPE_OFFSET] = type;
memcpy (buf + I2CP_HEADER_SIZE, payload, len);
boost::asio::async_write (*m_Socket, boost::asio::buffer (buf, l), boost::asio::transfer_all (),
std::bind(&I2CPSession::HandleI2CPMessageSent, shared_from_this (),
std::placeholders::_1, std::placeholders::_2, buf));
}
void I2CPSession::HandleI2CPMessageSent (const boost::system::error_code& ecode, std::size_t bytes_transferred, const uint8_t * buf)
{
delete[] buf;
if (ecode && ecode != boost::asio::error::operation_aborted)
Terminate ();
}
std::string I2CPSession::ExtractString (const uint8_t * buf, size_t len)
{
uint8_t l = buf[0];
if (l > len) l = len;
return std::string ((const char *)(buf + 1), l);
}
size_t I2CPSession::PutString (uint8_t * buf, size_t len, const std::string& str)
{
auto l = str.length ();
if (l + 1 >= len) l = len - 1;
if (l > 255) l = 255; // 1 byte max
buf[0] = l;
memcpy (buf + 1, str.c_str (), l);
return l + 1;
}
void I2CPSession::ExtractMapping (const uint8_t * buf, size_t len, std::map<std::string, std::string>& mapping)
// TODO: move to Base.cpp
{
size_t offset = 0;
while (offset < len)
{
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std::string param = ExtractString (buf + offset, len - offset);
offset += param.length ();
if (buf[offset] != '=')
{
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LogPrint (eLogWarning, "I2CP: Unexpected character ", buf[offset], " instead '=' after ", param);
break;
}
offset++;
std::string value = ExtractString (buf + offset, len - offset);
offset += value.length ();
if (buf[offset] != ';')
{
LogPrint (eLogWarning, "I2CP: Unexpected character ", buf[offset], " instead ';' after ", value);
break;
}
offset++;
mapping.insert (std::make_pair (param, value));
}
}
void I2CPSession::GetDateMessageHandler (const uint8_t * buf, size_t len)
{
// get version
auto version = ExtractString (buf, len);
auto l = version.length () + 1 + 8;
uint8_t * payload = new uint8_t[l];
// set date
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
htobe64buf (payload, ts);
// echo vesrion back
PutString (payload + 8, l - 8, version);
SendI2CPMessage (I2CP_SET_DATE_MESSAGE, payload, l);
delete[] payload;
}
void I2CPSession::CreateSessionMessageHandler (const uint8_t * buf, size_t len)
{
auto identity = std::make_shared<i2p::data::IdentityEx>();
size_t offset = identity->FromBuffer (buf, len);
uint16_t optionsSize = bufbe16toh (buf + offset);
offset += 2;
std::map<std::string, std::string> params;
ExtractMapping (buf + offset, optionsSize, params);
offset += optionsSize;
offset += 8; // date
if (identity->Verify (buf, offset, buf + offset)) // signature
{
bool isPublic = true;
if (params[I2CP_PARAM_DONT_PUBLISH_LEASESET] == "true") isPublic = false;
m_Destination = std::make_shared<I2CPDestination>(*this, identity, isPublic, params);
m_Destination->Start ();
SendSessionStatusMessage (1); // created
LogPrint (eLogDebug, "I2CP: session ", m_SessionID, " created");
}
else
{
LogPrint (eLogError, "I2CP: create session signature verification falied");
SendSessionStatusMessage (3); // invalid
}
}
void I2CPSession::DestroySessionMessageHandler (const uint8_t * buf, size_t len)
{
SendSessionStatusMessage (0); // destroy
LogPrint (eLogDebug, "I2CP: session ", m_SessionID, " destroyed");
Terminate ();
}
void I2CPSession::ReconfigureSessionMessageHandler (const uint8_t * buf, size_t len)
{
// TODO: implement actual reconfiguration
SendSessionStatusMessage (2); // updated
}
void I2CPSession::SendSessionStatusMessage (uint8_t status)
{
uint8_t buf[3];
htobe16buf (buf, m_SessionID);
buf[2] = status;
SendI2CPMessage (I2CP_SESSION_STATUS_MESSAGE, buf, 3);
}
void I2CPSession::SendMessageStatusMessage (uint32_t nonce, I2CPMessageStatus status)
{
uint8_t buf[15];
htobe16buf (buf, m_SessionID);
htobe32buf (buf + 2, m_MessageID++);
buf[6] = (uint8_t)status;
memset (buf + 7, 0, 4); // size
htobe32buf (buf + 11, nonce);
SendI2CPMessage (I2CP_MESSAGE_STATUS_MESSAGE, buf, 15);
}
void I2CPSession::CreateLeaseSetMessageHandler (const uint8_t * buf, size_t len)
{
uint16_t sessionID = bufbe16toh (buf);
if (sessionID == m_SessionID)
{
size_t offset = 2;
if (m_Destination)
{
offset += i2p::crypto::DSA_PRIVATE_KEY_LENGTH; // skip signing private key
// we always assume this field as 20 bytes (DSA) regardless actual size
// instead of
//offset += m_Destination->GetIdentity ()->GetSigningPrivateKeyLen ();
m_Destination->SetEncryptionPrivateKey (buf + offset);
offset += 256;
m_Destination->LeaseSetCreated (buf + offset, len - offset);
}
}
else
LogPrint (eLogError, "I2CP: unexpected sessionID ", sessionID);
}
void I2CPSession::SendMessageMessageHandler (const uint8_t * buf, size_t len)
{
uint16_t sessionID = bufbe16toh (buf);
if (sessionID == m_SessionID)
{
size_t offset = 2;
if (m_Destination)
{
i2p::data::IdentityEx identity;
offset += identity.FromBuffer (buf + offset, len - offset);
uint32_t payloadLen = bufbe32toh (buf + offset);
offset += 4;
uint32_t nonce = bufbe32toh (buf + offset + payloadLen);
SendMessageStatusMessage (nonce, eI2CPMessageStatusAccepted); // accepted
m_Destination->SendMsgTo (buf + offset, payloadLen, identity.GetIdentHash (), nonce);
}
}
else
LogPrint (eLogError, "I2CP: unexpected sessionID ", sessionID);
}
void I2CPSession::SendMessageExpiresMessageHandler (const uint8_t * buf, size_t len)
{
SendMessageMessageHandler (buf, len - 8); // ignore flags(2) and expiration(6)
}
void I2CPSession::HostLookupMessageHandler (const uint8_t * buf, size_t len)
{
uint16_t sessionID = bufbe16toh (buf);
if (sessionID == m_SessionID)
{
uint32_t requestID = bufbe32toh (buf + 2);
//uint32_t timeout = bufbe32toh (buf + 6);
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i2p::data::IdentHash ident;
switch (buf[10])
{
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case 0: // hash
ident = i2p::data::IdentHash (buf + 11);
break;
case 1: // address
{
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auto name = ExtractString (buf + 11, len - 11);
if (!i2p::client::context.GetAddressBook ().GetIdentHash (name, ident))
{
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LogPrint (eLogError, "I2CP: address ", name, " not found");
SendHostReplyMessage (requestID, nullptr);
return;
}
break;
}
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default:
LogPrint (eLogError, "I2CP: request type ", (int)buf[10], " is not supported");
SendHostReplyMessage (requestID, nullptr);
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return;
}
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if (m_Destination)
{
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auto ls = m_Destination->FindLeaseSet (ident);
if (ls)
SendHostReplyMessage (requestID, ls->GetIdentity ());
else
{
auto s = shared_from_this ();
m_Destination->RequestDestination (ident,
[s, requestID](std::shared_ptr<i2p::data::LeaseSet> leaseSet)
{
s->SendHostReplyMessage (requestID, leaseSet ? leaseSet->GetIdentity () : nullptr);
});
}
}
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else
SendHostReplyMessage (requestID, nullptr);
}
else
LogPrint (eLogError, "I2CP: unexpected sessionID ", sessionID);
}
void I2CPSession::SendHostReplyMessage (uint32_t requestID, std::shared_ptr<const i2p::data::IdentityEx> identity)
{
if (identity)
{
size_t l = identity->GetFullLen () + 7;
uint8_t * buf = new uint8_t[l];
htobe16buf (buf, m_SessionID);
htobe32buf (buf + 2, requestID);
buf[6] = 0; // result code
identity->ToBuffer (buf + 7, l - 7);
SendI2CPMessage (I2CP_HOST_REPLY_MESSAGE, buf, l);
delete[] buf;
}
else
{
uint8_t buf[7];
htobe16buf (buf, m_SessionID);
htobe32buf (buf + 2, requestID);
buf[6] = 1; // result code
SendI2CPMessage (I2CP_HOST_REPLY_MESSAGE, buf, 7);
}
}
void I2CPSession::DestLookupMessageHandler (const uint8_t * buf, size_t len)
{
if (m_Destination)
{
auto ls = m_Destination->FindLeaseSet (buf);
if (ls)
{
auto l = ls->GetIdentity ()->GetFullLen ();
uint8_t * identBuf = new uint8_t[l];
ls->GetIdentity ()->ToBuffer (identBuf, l);
SendI2CPMessage (I2CP_DEST_REPLY_MESSAGE, identBuf, l);
delete[] identBuf;
}
else
{
auto s = shared_from_this ();
i2p::data::IdentHash ident (buf);
m_Destination->RequestDestination (ident,
[s, ident](std::shared_ptr<i2p::data::LeaseSet> leaseSet)
{
if (leaseSet) // found
{
auto l = leaseSet->GetIdentity ()->GetFullLen ();
uint8_t * identBuf = new uint8_t[l];
leaseSet->GetIdentity ()->ToBuffer (identBuf, l);
s->SendI2CPMessage (I2CP_DEST_REPLY_MESSAGE, identBuf, l);
delete[] identBuf;
}
else
s->SendI2CPMessage (I2CP_DEST_REPLY_MESSAGE, ident, 32); // not found
});
}
}
else
SendI2CPMessage (I2CP_DEST_REPLY_MESSAGE, buf, 32);
}
void I2CPSession::GetBandwidthLimitsMessageHandler (const uint8_t * buf, size_t len)
{
uint8_t limits[64];
memset (limits, 0, 64);
htobe32buf (limits, i2p::transport::transports.GetInBandwidth ()); // inbound
htobe32buf (limits + 4, i2p::transport::transports.GetOutBandwidth ()); // outbound
SendI2CPMessage (I2CP_BANDWIDTH_LIMITS_MESSAGE, limits, 64);
}
void I2CPSession::SendMessagePayloadMessage (const uint8_t * payload, size_t len)
{
// we don't use SendI2CPMessage to eliminate additional copy
auto l = len + 10 + I2CP_HEADER_SIZE;
uint8_t * buf = new uint8_t[l];
htobe32buf (buf + I2CP_HEADER_LENGTH_OFFSET, len + 10);
buf[I2CP_HEADER_TYPE_OFFSET] = I2CP_MESSAGE_PAYLOAD_MESSAGE;
htobe16buf (buf + I2CP_HEADER_SIZE, m_SessionID);
htobe32buf (buf + I2CP_HEADER_SIZE + 2, m_MessageID++);
htobe32buf (buf + I2CP_HEADER_SIZE + 6, len);
memcpy (buf + I2CP_HEADER_SIZE + 10, payload, len);
boost::asio::async_write (*m_Socket, boost::asio::buffer (buf, l), boost::asio::transfer_all (),
std::bind(&I2CPSession::HandleI2CPMessageSent, shared_from_this (),
std::placeholders::_1, std::placeholders::_2, buf));
}
I2CPServer::I2CPServer (const std::string& interface, int port):
m_IsRunning (false), m_Thread (nullptr),
m_Acceptor (m_Service, boost::asio::ip::tcp::endpoint(boost::asio::ip::address::from_string(interface), port))
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{
memset (m_MessagesHandlers, 0, sizeof (m_MessagesHandlers));
m_MessagesHandlers[I2CP_GET_DATE_MESSAGE] = &I2CPSession::GetDateMessageHandler;
m_MessagesHandlers[I2CP_CREATE_SESSION_MESSAGE] = &I2CPSession::CreateSessionMessageHandler;
m_MessagesHandlers[I2CP_DESTROY_SESSION_MESSAGE] = &I2CPSession::DestroySessionMessageHandler;
m_MessagesHandlers[I2CP_RECONFIGURE_SESSION_MESSAGE] = &I2CPSession::ReconfigureSessionMessageHandler;
m_MessagesHandlers[I2CP_CREATE_LEASESET_MESSAGE] = &I2CPSession::CreateLeaseSetMessageHandler;
m_MessagesHandlers[I2CP_SEND_MESSAGE_MESSAGE] = &I2CPSession::SendMessageMessageHandler;
m_MessagesHandlers[I2CP_SEND_MESSAGE_EXPIRES_MESSAGE] = &I2CPSession::SendMessageExpiresMessageHandler;
m_MessagesHandlers[I2CP_HOST_LOOKUP_MESSAGE] = &I2CPSession::HostLookupMessageHandler;
m_MessagesHandlers[I2CP_DEST_LOOKUP_MESSAGE] = &I2CPSession::DestLookupMessageHandler;
m_MessagesHandlers[I2CP_GET_BANDWIDTH_LIMITS_MESSAGE] = &I2CPSession::GetBandwidthLimitsMessageHandler;
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}
I2CPServer::~I2CPServer ()
{
if (m_IsRunning)
Stop ();
}
void I2CPServer::Start ()
{
Accept ();
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&I2CPServer::Run, this));
}
void I2CPServer::Stop ()
{
m_IsRunning = false;
m_Acceptor.cancel ();
for (auto it: m_Sessions)
it.second->Stop ();
m_Sessions.clear ();
m_Service.stop ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = nullptr;
}
}
void I2CPServer::Run ()
{
while (m_IsRunning)
{
try
{
m_Service.run ();
}
catch (std::exception& ex)
{
LogPrint (eLogError, "I2CP: runtime exception: ", ex.what ());
}
}
}
void I2CPServer::Accept ()
{
auto newSocket = std::make_shared<boost::asio::ip::tcp::socket> (m_Service);
m_Acceptor.async_accept (*newSocket, std::bind (&I2CPServer::HandleAccept, this,
std::placeholders::_1, newSocket));
}
void I2CPServer::HandleAccept(const boost::system::error_code& ecode, std::shared_ptr<boost::asio::ip::tcp::socket> socket)
{
if (!ecode && socket)
{
boost::system::error_code ec;
auto ep = socket->remote_endpoint (ec);
if (!ec)
{
LogPrint (eLogDebug, "I2CP: new connection from ", ep);
auto session = std::make_shared<I2CPSession>(*this, socket);
m_Sessions[session->GetSessionID ()] = session;
session->Start ();
}
else
LogPrint (eLogError, "I2CP: incoming connection error ", ec.message ());
}
else
LogPrint (eLogError, "I2CP: accept error: ", ecode.message ());
if (ecode != boost::asio::error::operation_aborted)
Accept ();
}
void I2CPServer::RemoveSession (uint16_t sessionID)
{
m_Sessions.erase (sessionID);
}
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}
}