i2pd/HTTPProxy.cpp

#include <cstring>
#include <cassert>
#include <boost/lexical_cast.hpp>
#include <boost/regex.hpp>
#include <string>
#include <atomic>
#include "HTTPProxy.h"
#include "util.h"
#include "Identity.h"
#include "Streaming.h"
#include "Destination.h"
#include "ClientContext.h"
#include "I2PEndian.h"
#include "I2PTunnel.h"

namespace i2p
{
namespace proxy
{
    static const size_t http_buffer_size = 8192;
    class HTTPProxyHandler: public i2p::client::I2PServiceHandler, public std::enable_shared_from_this<HTTPProxyHandler> 
    {
        private:
            enum state 
            {
                GET_METHOD,
                GET_HOSTNAME,
                GET_HTTPV,
                GET_HTTPVNL, //TODO: fallback to finding HOst: header if needed
                DONE
            };

            void EnterState(state nstate);
            bool HandleData(uint8_t *http_buff, std::size_t len);
            void HandleSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered);
            void Terminate();
            void AsyncSockRead();
            void HTTPRequestFailed(/*std::string message*/);
            void ExtractRequest();
            bool ValidateHTTPRequest();
            void HandleJumpServices();
            bool CreateHTTPRequest(uint8_t *http_buff, std::size_t len);
            void SentHTTPFailed(const boost::system::error_code & ecode);
            void HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream);

            uint8_t m_http_buff[http_buffer_size];
            std::shared_ptr<boost::asio::ip::tcp::socket> m_sock;
            std::string m_request; //Data left to be sent
            std::string m_url; //URL
            std::string m_method; //Method
            std::string m_version; //HTTP version
            std::string m_address; //Address
            std::string m_path; //Path
            int m_port; //Port
            state m_state;//Parsing state

        public:

            HTTPProxyHandler(HTTPProxyServer * parent, std::shared_ptr<boost::asio::ip::tcp::socket> sock) : 
                I2PServiceHandler(parent), m_sock(sock)
                { EnterState(GET_METHOD); }
            ~HTTPProxyHandler() { Terminate(); }
            void Handle () { AsyncSockRead(); }
    };

    void HTTPProxyHandler::AsyncSockRead()
    {
        LogPrint(eLogDebug,"--- HTTP Proxy async sock read");
        if(m_sock) {
            m_sock->async_receive(boost::asio::buffer(m_http_buff, http_buffer_size),
                        std::bind(&HTTPProxyHandler::HandleSockRecv, shared_from_this(),
                                std::placeholders::_1, std::placeholders::_2));
        } else {
            LogPrint(eLogError,"--- HTTP Proxy no socket for read");
        }
    }

    void HTTPProxyHandler::Terminate() {
        if (Kill()) return;
        if (m_sock) 
        {
            LogPrint(eLogDebug,"--- HTTP Proxy close sock");
            m_sock->close();
            m_sock = nullptr;
        }
        Done(shared_from_this());
    }

    /* All hope is lost beyond this point */
    //TODO: handle this apropriately
    void HTTPProxyHandler::HTTPRequestFailed(/*HTTPProxyHandler::errTypes error*/)
    {
        static std::string response = "HTTP/1.0 500 Internal Server Error\r\nContent-type: text/html\r\nContent-length: 0\r\n";
        boost::asio::async_write(*m_sock, boost::asio::buffer(response,response.size()),
                     std::bind(&HTTPProxyHandler::SentHTTPFailed, shared_from_this(), std::placeholders::_1));
    }

    void HTTPProxyHandler::EnterState(HTTPProxyHandler::state nstate) 
    {
        m_state = nstate;
    }

    void HTTPProxyHandler::ExtractRequest()
    {
        LogPrint(eLogDebug,"--- HTTP Proxy method is: ", m_method, "\nRequest is: ", m_url);
        std::string server="";
        std::string port="80";
        boost::regex rHTTP("http://(.*?)(:(\\d+))?(/.*)");
        boost::smatch m;
        std::string path;
        if(boost::regex_search(m_url, m, rHTTP, boost::match_extra)) 
        {
            server=m[1].str();
            if (m[2].str() != "")  port=m[3].str();
            path=m[4].str();
        }
        LogPrint(eLogDebug,"--- HTTP Proxy server is: ",server, " port is: ", port, "\n path is: ",path);
        m_address = server;
        m_port = boost::lexical_cast<int>(port);
        m_path = path;
    }

    bool HTTPProxyHandler::ValidateHTTPRequest() 
    {
        if ( m_version != "HTTP/1.0" && m_version != "HTTP/1.1" ) 
        {
            LogPrint(eLogError,"--- HTTP Proxy unsupported version: ", m_version);
            HTTPRequestFailed(); //TODO: send right stuff
            return false;
        }
        return true;
    }

    void HTTPProxyHandler::HandleJumpServices() 
    {
        static const char * helpermark1 = "?i2paddresshelper=";
        static const char * helpermark2 = "&i2paddresshelper=";
        size_t addressHelperPos1 = m_path.rfind (helpermark1);
        size_t addressHelperPos2 = m_path.rfind (helpermark2);
        size_t addressHelperPos;
        if (addressHelperPos1 == std::string::npos)
        {
            if (addressHelperPos2 == std::string::npos)
                return; //Not a jump service
            else
                addressHelperPos = addressHelperPos2;
        }
        else
        {
            if (addressHelperPos2 == std::string::npos)
                addressHelperPos = addressHelperPos1;
            else if ( addressHelperPos1 > addressHelperPos2 )
                addressHelperPos = addressHelperPos1;
            else
                addressHelperPos = addressHelperPos2;
        }
        auto base64 = m_path.substr (addressHelperPos + strlen(helpermark1));
        base64 = i2p::util::http::urlDecode(base64); //Some of the symbols may be urlencoded
        LogPrint (eLogDebug,"Jump service for ", m_address, " found at ", base64, ". Inserting to address book");
        //TODO: this is very dangerous and broken. We should ask the user before doing anything see http://pastethis.i2p/raw/pn5fL4YNJL7OSWj3Sc6N/
        //TODO: we could redirect the user again to avoid dirtiness in the browser
        i2p::client::context.GetAddressBook ().InsertAddress (m_address, base64);
        m_path.erase(addressHelperPos);
    }

    bool HTTPProxyHandler::CreateHTTPRequest(uint8_t *http_buff, std::size_t len) 
    {
        ExtractRequest(); //TODO: parse earlier
        if (!ValidateHTTPRequest()) return false;
        HandleJumpServices();
        m_request = m_method;
        m_request.push_back(' ');
        m_request += m_path;
        m_request.push_back(' ');
        m_request += m_version;
        m_request.push_back('\r');
        m_request.push_back('\n');
        m_request.append("Connection: close\r\n");
        m_request.append(reinterpret_cast<const char *>(http_buff),len);
        return true;
    }

    bool HTTPProxyHandler::HandleData(uint8_t *http_buff, std::size_t len)
    {
        assert(len); // This should always be called with a least a byte left to parse
        while (len > 0) 
        {
            //TODO: fallback to finding HOst: header if needed
            switch (m_state) 
            {
                case GET_METHOD:
                    switch (*http_buff) 
                    {
                        case ' ': EnterState(GET_HOSTNAME); break;
                        default: m_method.push_back(*http_buff); break;
                    }
                break;
                case GET_HOSTNAME:
                    switch (*http_buff) 
                    {
                        case ' ': EnterState(GET_HTTPV); break;
                        default: m_url.push_back(*http_buff); break;
                    }
                break;
                case GET_HTTPV:
                    switch (*http_buff) 
                    {
                        case '\r': EnterState(GET_HTTPVNL); break;
                        default: m_version.push_back(*http_buff); break;
                    }
                break;
                case GET_HTTPVNL:
                    switch (*http_buff) 
                    {
                        case '\n': EnterState(DONE); break;
                        default:
                            LogPrint(eLogError,"--- HTTP Proxy rejected invalid request ending with: ", ((int)*http_buff));
                            HTTPRequestFailed(); //TODO: add correct code
                            return false;
                    }
                break;
                default:
                    LogPrint(eLogError,"--- HTTP Proxy invalid state: ", m_state);
                    HTTPRequestFailed(); //TODO: add correct code 500
                    return false;
            }
            http_buff++;
            len--;
            if (m_state == DONE)
                return CreateHTTPRequest(http_buff,len);
        }
        return true;
    }

    void HTTPProxyHandler::HandleSockRecv(const boost::system::error_code & ecode, std::size_t len)
    {
        LogPrint(eLogDebug,"--- HTTP Proxy sock recv: ", len);
        if(ecode) 
        {
            LogPrint(eLogWarning," --- HTTP Proxy sock recv got error: ", ecode);
                        Terminate();
            return;
        }

        if (HandleData(m_http_buff, len)) 
        {
            if (m_state == DONE) 
            {
                LogPrint(eLogInfo,"--- HTTP Proxy requested: ", m_url);
                GetOwner()->CreateStream (std::bind (&HTTPProxyHandler::HandleStreamRequestComplete,
                        shared_from_this(), std::placeholders::_1), m_address, m_port);
            } 
            else 
                AsyncSockRead();
        }

    }

    void HTTPProxyHandler::SentHTTPFailed(const boost::system::error_code & ecode)
    {
        if (!ecode)
            Terminate();
        else 
        {
            LogPrint (eLogError,"--- HTTP Proxy Closing socket after sending failure because: ", ecode.message ());
            Terminate();
        }
    }

    void HTTPProxyHandler::HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream)
    {
        if (stream) 
        {
            if (Kill()) return;
            LogPrint (eLogInfo,"--- HTTP Proxy New I2PTunnel connection");
            auto connection = std::make_shared<i2p::client::I2PTunnelConnection>(GetOwner(), m_sock, stream);
            GetOwner()->AddHandler (connection);
            connection->I2PConnect (reinterpret_cast<const uint8_t*>(m_request.data()), m_request.size());
            Done(shared_from_this());
        } 
        else 
        {
            LogPrint (eLogError,"--- HTTP Proxy Issue when creating the stream, check the previous warnings for more info.");
            HTTPRequestFailed(); // TODO: Send correct error message host unreachable
        }
    }

    HTTPProxyServer::HTTPProxyServer(const std::string& address, int port, std::shared_ptr<i2p::client::ClientDestination> localDestination): 
        TCPIPAcceptor(address, port, localDestination ? localDestination : i2p::client::context.GetSharedLocalDestination ()) 
    {
    }
    
    std::shared_ptr<i2p::client::I2PServiceHandler> HTTPProxyServer::CreateHandler(std::shared_ptr<boost::asio::ip::tcp::socket> socket)
    {
        return std::make_shared<HTTPProxyHandler> (this, socket);
    }

}
}