i2pd/I2PTunnel.cpp

#include <cassert>
#include "base64.h"
#include "Log.h"
#include "Destination.h"
#include "ClientContext.h"
#include "I2PTunnel.h"

namespace i2p
{
namespace client
{
    I2PTunnelConnection::I2PTunnelConnection (I2PService * owner, std::shared_ptr<boost::asio::ip::tcp::socket> socket,
        std::shared_ptr<const i2p::data::LeaseSet> leaseSet, int port): 
        I2PServiceHandler(owner), m_Socket (socket), m_RemoteEndpoint (socket->remote_endpoint ()),
        m_IsQuiet (true)
    {
        m_Stream = GetOwner()->GetLocalDestination ()->CreateStream (leaseSet, port);
    }   

    I2PTunnelConnection::I2PTunnelConnection (I2PService * owner,
        std::shared_ptr<boost::asio::ip::tcp::socket> socket, std::shared_ptr<i2p::stream::Stream> stream):
        I2PServiceHandler(owner), m_Socket (socket), m_Stream (stream),
        m_RemoteEndpoint (socket->remote_endpoint ()), m_IsQuiet (true)
    {
    }

    I2PTunnelConnection::I2PTunnelConnection (I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream,
        std::shared_ptr<boost::asio::ip::tcp::socket> socket, const boost::asio::ip::tcp::endpoint& target, bool quiet):
        I2PServiceHandler(owner), m_Socket (socket), m_Stream (stream),
        m_RemoteEndpoint (target), m_IsQuiet (quiet)
    {
    }

    I2PTunnelConnection::~I2PTunnelConnection ()
    {
    }   

    void I2PTunnelConnection::I2PConnect (const uint8_t * msg, size_t len)
    {
        if (m_Stream)
        {
            if (msg)
                m_Stream->Send (msg, len); // connect and send
            else    
                m_Stream->Send (m_Buffer, 0); // connect
        }
        StreamReceive ();
        Receive ();
    }
        
    void I2PTunnelConnection::Connect ()
    {
        if (m_Socket)
            m_Socket->async_connect (m_RemoteEndpoint, std::bind (&I2PTunnelConnection::HandleConnect,
                shared_from_this (), std::placeholders::_1));
    }   
        
    void I2PTunnelConnection::Terminate ()
    {
        if (Kill()) return;
        if (m_Stream)
        {
            m_Stream->Close ();
            m_Stream.reset ();
        }   
        m_Socket->close ();
        Done(shared_from_this ());
    }           

    void I2PTunnelConnection::Receive ()
    {
        m_Socket->async_read_some (boost::asio::buffer(m_Buffer, I2P_TUNNEL_CONNECTION_BUFFER_SIZE),                
            std::bind(&I2PTunnelConnection::HandleReceived, shared_from_this (), 
            std::placeholders::_1, std::placeholders::_2));
    }   
    
    void I2PTunnelConnection::HandleReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
    {
        if (ecode)
        {
            LogPrint ("I2PTunnel read error: ", ecode.message ());
            if (ecode != boost::asio::error::operation_aborted)
                Terminate ();
        }
        else
        {   
            if (m_Stream)
            {   
                auto s = shared_from_this ();
                m_Stream->AsyncSend (m_Buffer, bytes_transferred,
                    [s](const boost::system::error_code& ecode)
                    {
                        if (!ecode)
                            s->Receive ();
                        else
                            s->Terminate ();
                    });
            }   
        }
    }   

    void I2PTunnelConnection::HandleWrite (const boost::system::error_code& ecode)
    {
        if (ecode)
        {
            LogPrint ("I2PTunnel write error: ", ecode.message ());
            if (ecode != boost::asio::error::operation_aborted)
                Terminate ();
        }
        else
            StreamReceive ();
    }

    void I2PTunnelConnection::StreamReceive ()
    {
        if (m_Stream)
            m_Stream->AsyncReceive (boost::asio::buffer (m_StreamBuffer, I2P_TUNNEL_CONNECTION_BUFFER_SIZE),
                std::bind (&I2PTunnelConnection::HandleStreamReceive, shared_from_this (),
                    std::placeholders::_1, std::placeholders::_2),
                I2P_TUNNEL_CONNECTION_MAX_IDLE);
    }   

    void I2PTunnelConnection::HandleStreamReceive (const boost::system::error_code& ecode, std::size_t bytes_transferred)
    {
        if (ecode)
        {
            LogPrint ("I2PTunnel stream read error: ", ecode.message ());
            if (ecode != boost::asio::error::operation_aborted)
                Terminate ();
        }
        else
            Write (m_StreamBuffer, bytes_transferred);
    }

    void I2PTunnelConnection::Write (const uint8_t * buf, size_t len)
    {
        m_Socket->async_send (boost::asio::buffer (buf, len),
            std::bind (&I2PTunnelConnection::HandleWrite, shared_from_this (), std::placeholders::_1));
    }

    void I2PTunnelConnection::HandleConnect (const boost::system::error_code& ecode)
    {
        if (ecode)
        {
            LogPrint ("I2PTunnel connect error: ", ecode.message ());
            Terminate ();
        }
        else
        {
            LogPrint ("I2PTunnel connected");
            if (m_IsQuiet)
                StreamReceive ();
            else
            {
                // send destination first like received from I2P
                std::string dest = m_Stream->GetRemoteIdentity ().ToBase64 ();
                dest += "\n";
                memcpy (m_StreamBuffer, dest.c_str (), dest.size ());
                HandleStreamReceive (boost::system::error_code (), dest.size ());
            }   
            Receive (); 
        }
    }

    I2PTunnelConnectionHTTP::I2PTunnelConnectionHTTP (I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream,
        std::shared_ptr<boost::asio::ip::tcp::socket> socket, 
        const boost::asio::ip::tcp::endpoint& target, const std::string& host):
        I2PTunnelConnection (owner, stream, socket, target), m_Host (host), m_HeaderSent (false)
    {
    }

    void I2PTunnelConnectionHTTP::Write (const uint8_t * buf, size_t len)
    {
        if (m_HeaderSent)
            I2PTunnelConnection::Write (buf, len);
        else
        {   
            m_InHeader.clear ();
            m_InHeader.write ((const char *)buf, len);
            std::string line;
            bool endOfHeader = false;
            while (!endOfHeader)
            {
                std::getline(m_InHeader, line);
                if (!m_InHeader.fail ())
                {
                    if (line.find ("Host:") != std::string::npos)
                        m_OutHeader << "Host: " << m_Host << "\r\n";
                    else
                        m_OutHeader << line << "\n";
                    if (line == "\r") endOfHeader = true;
                }
                else
                    break;
            }

            if (endOfHeader)
            {
                m_OutHeader << m_InHeader.str (); // data right after header
                m_HeaderSent = true;
                I2PTunnelConnection::Write ((uint8_t *)m_OutHeader.str ().c_str (), m_OutHeader.str ().length ());
            }
        }   
    }

    /* This handler tries to stablish a connection with the desired server and dies if it fails to do so */
    class I2PClientTunnelHandler: public I2PServiceHandler, public std::enable_shared_from_this<I2PClientTunnelHandler>
    {
        public:
            I2PClientTunnelHandler (I2PClientTunnel * parent, i2p::data::IdentHash destination,
                int destinationPort, std::shared_ptr<boost::asio::ip::tcp::socket> socket):
                I2PServiceHandler(parent), m_DestinationIdentHash(destination), 
                m_DestinationPort (destinationPort), m_Socket(socket) {};
            void Handle();
            void Terminate();
        private:
            void HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream);
            i2p::data::IdentHash m_DestinationIdentHash;
            int m_DestinationPort;
            std::shared_ptr<boost::asio::ip::tcp::socket> m_Socket;
    };

    void I2PClientTunnelHandler::Handle()
    {
        GetOwner()->GetLocalDestination ()->CreateStream ( 
            std::bind (&I2PClientTunnelHandler::HandleStreamRequestComplete, shared_from_this(), std::placeholders::_1), 
            m_DestinationIdentHash, m_DestinationPort);
    }

    void I2PClientTunnelHandler::HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream)
    {
        if (stream)
        {
            if (Kill()) return;
            LogPrint (eLogInfo,"New I2PTunnel connection");
            auto connection = std::make_shared<I2PTunnelConnection>(GetOwner(), m_Socket, stream);
            GetOwner()->AddHandler (connection);
            connection->I2PConnect ();
            Done(shared_from_this());
        }
        else
        {
            LogPrint (eLogError,"I2P Client Tunnel Issue when creating the stream, check the previous warnings for more info.");
            Terminate();
        }
    }

    void I2PClientTunnelHandler::Terminate()
    {
        if (Kill()) return;
        if (m_Socket)
        {
            m_Socket->close();
            m_Socket = nullptr;
        }
        Done(shared_from_this());
    }

    I2PClientTunnel::I2PClientTunnel(
        const std::string& destination, const std::string& address, int port,
        std::shared_ptr<ClientDestination> localDestination, int destinationPort
    )
        : TCPIPAcceptor(address, port, localDestination), m_Destination(destination),
          m_DestinationIdentHash(nullptr), m_DestinationPort(destinationPort)
    {}  

    void I2PClientTunnel::Start ()
    {
        TCPIPAcceptor::Start ();
        GetIdentHash();
    }

    void I2PClientTunnel::Stop ()
    {
        TCPIPAcceptor::Stop();
        auto *originalIdentHash = m_DestinationIdentHash;
        m_DestinationIdentHash = nullptr;
        delete originalIdentHash;
    }

    /* HACK: maybe we should create a caching IdentHash provider in AddressBook */
    const i2p::data::IdentHash * I2PClientTunnel::GetIdentHash ()
    {
        if (!m_DestinationIdentHash)
        {
            i2p::data::IdentHash identHash;
            if (i2p::client::context.GetAddressBook ().GetIdentHash (m_Destination, identHash))
                m_DestinationIdentHash = new i2p::data::IdentHash (identHash);
            else
                LogPrint (eLogWarning,"Remote destination ", m_Destination, " not found");
        }
        return m_DestinationIdentHash;
    }

    std::shared_ptr<I2PServiceHandler> I2PClientTunnel::CreateHandler(std::shared_ptr<boost::asio::ip::tcp::socket> socket)
    {
        const i2p::data::IdentHash *identHash = GetIdentHash();
        if (identHash)
            return  std::make_shared<I2PClientTunnelHandler>(this, *identHash, m_DestinationPort, socket);
        else
            return nullptr;
    }

    I2PServerTunnel::I2PServerTunnel (const std::string& address, int port, 
        std::shared_ptr<ClientDestination> localDestination, int inport): 
        I2PService (localDestination), m_Address (address), m_Port (port), m_IsAccessList (false)
    {
        m_PortDestination = localDestination->CreateStreamingDestination (inport > 0 ? inport : port);
    }
    
    void I2PServerTunnel::Start ()
    {
        m_Endpoint.port (m_Port);   
        boost::system::error_code ec;
        auto addr = boost::asio::ip::address::from_string (m_Address, ec);
        if (!ec)    
        {
            m_Endpoint.address (addr);
            Accept ();
        }
        else
        {
            auto resolver = std::make_shared<boost::asio::ip::tcp::resolver>(GetService ());
            resolver->async_resolve (boost::asio::ip::tcp::resolver::query (m_Address, ""), 
                std::bind (&I2PServerTunnel::HandleResolve, this, 
                    std::placeholders::_1, std::placeholders::_2, resolver));
        }   
    }

    void I2PServerTunnel::Stop ()
    {
        ClearHandlers ();
    }   

    void I2PServerTunnel::HandleResolve (const boost::system::error_code& ecode, boost::asio::ip::tcp::resolver::iterator it, 
        std::shared_ptr<boost::asio::ip::tcp::resolver> resolver)
    {   
        if (!ecode)
        {   
            auto addr = (*it).endpoint ().address ();
            LogPrint (eLogInfo, "server tunnel ", (*it).host_name (), " has been resolved to ", addr);  
            m_Endpoint.address (addr);
            Accept ();  
        }   
        else
            LogPrint (eLogError, "Unable to resolve server tunnel address: ", ecode.message ());
    }

    void I2PServerTunnel::SetAccessList (const std::set<i2p::data::IdentHash>& accessList)
    {
        m_AccessList = accessList;
        m_IsAccessList = true;      
    }

    void I2PServerTunnel::Accept ()
    {
        if (m_PortDestination)
            m_PortDestination->SetAcceptor (std::bind (&I2PServerTunnel::HandleAccept, this, std::placeholders::_1));

        auto localDestination = GetLocalDestination (); 
        if (localDestination)
        {
            if (!localDestination->IsAcceptingStreams ()) // set it as default if not set yet
                localDestination->AcceptStreams (std::bind (&I2PServerTunnel::HandleAccept, this, std::placeholders::_1));
        }
        else
            LogPrint ("Local destination not set for server tunnel");
    }

    void I2PServerTunnel::HandleAccept (std::shared_ptr<i2p::stream::Stream> stream)
    {
        if (stream)
        {   
            if (m_IsAccessList)
            {
                if (!m_AccessList.count (stream->GetRemoteIdentity ().GetIdentHash ()))
                {
                    LogPrint (eLogWarning, "Address ", stream->GetRemoteIdentity ().GetIdentHash ().ToBase32 (), " is not in white list. Incoming connection dropped");
                    stream->Close ();
                    return;
                }
            }
            CreateI2PConnection (stream);
        }   
    }

    void I2PServerTunnel::CreateI2PConnection (std::shared_ptr<i2p::stream::Stream> stream)
    {
        auto conn = std::make_shared<I2PTunnelConnection> (this, stream, std::make_shared<boost::asio::ip::tcp::socket> (GetService ()), GetEndpoint ());
        AddHandler (conn);
        conn->Connect ();
    }

    I2PServerTunnelHTTP::I2PServerTunnelHTTP (const std::string& address, int port, std::shared_ptr<ClientDestination> localDestination, int inport):
        I2PServerTunnel (address, port, localDestination, inport)
    {
    }

    void I2PServerTunnelHTTP::CreateI2PConnection (std::shared_ptr<i2p::stream::Stream> stream)
    {
        auto conn = std::make_shared<I2PTunnelConnectionHTTP> (this, stream, std::make_shared<boost::asio::ip::tcp::socket> (GetService ()), GetEndpoint (), GetAddress ());
        AddHandler (conn);
        conn->Connect ();
    }
}       
}