/*
 * GSSAPIAuthRequestHandler.cpp
 *
 * Copyright (C) 2008 Matthias Schiffer <matthias@gamezock.de>
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "GSSAPIAuthRequestHandler.h"
#include <Common/Logger.h>
#include <Net/Connection.h>
#include <Net/Packets/ErrorPacket.h>

#include <cstring>

namespace Mad {
namespace Core {
namespace RequestHandlers {

// TODO Error handling

void GSSAPIAuthRequestHandler::handlePacket(Net::Connection *connection, const Net::Packet &packet) {
  if(packet.getType() != Net::Packet::GSSAPI_AUTH) {
    Common::Logger::log(Common::Logger::ERROR, "Received an unexpected packet.");
    connection->send(Net::Packets::ErrorPacket(Net::Packet::ERROR, packet.getRequestId(), Common::Exception(Common::Exception::UNEXPECTED_PACKET)));

    signalFinished().emit();
    return;
  }

  OM_uint32 majStat, minStat;
  gss_buffer_desc recvBuffer, sendBuffer;

  // Needs error handling!

  if(gssContinue) {
    recvBuffer.length = packet.getLength();
    recvBuffer.value = std::malloc(recvBuffer.length);
    std::memcpy(recvBuffer.value, packet.getData(), recvBuffer.length);

    majStat = gss_accept_sec_context(&minStat, &gssContext, GSS_C_NO_CREDENTIAL, &recvBuffer, GSS_C_NO_CHANNEL_BINDINGS, 0, 0, &sendBuffer, 0, 0, 0);

    std::free(recvBuffer.value);

    if(majStat == GSS_S_COMPLETE) {
      Common::Logger::log(Common::Logger::VERBOSE, "GSS context established.");
      gssContinue = false;
    }
    else if(majStat != GSS_S_CONTINUE_NEEDED) {
      gss_release_buffer(&minStat, &sendBuffer);
      return;
    }

    if(!connection->send(Net::Packet(Net::Packet::GSSAPI_AUTH, packet.getRequestId(), sendBuffer.value, sendBuffer.length))) {
      gss_release_buffer(&minStat, &sendBuffer);
      return;
    }

    gss_release_buffer(&minStat, &sendBuffer);
  }
  else if(!sentSignature) {
    if(packet.getLength() != 0)
      return;

    const gnutls_datum_t *cert = connection->getCertificate();

    recvBuffer.length = cert->size;
    recvBuffer.value = cert->data;

    majStat = gss_get_mic(&minStat, gssContext, GSS_C_QOP_DEFAULT, &recvBuffer, &sendBuffer);

    if(majStat != GSS_S_COMPLETE) {
      gss_release_buffer(&minStat, &sendBuffer);
      return;
    }

    if(!connection->send(Net::Packet(Net::Packet::GSSAPI_AUTH, packet.getRequestId(), sendBuffer.value, sendBuffer.length))) {
      gss_release_buffer(&minStat, &sendBuffer);
      return;
    }

    gss_release_buffer(&minStat, &sendBuffer);

    sentSignature = true;
  }
  else {
    recvBuffer.length = packet.getLength();
    recvBuffer.value = std::malloc(recvBuffer.length);
    std::memcpy(recvBuffer.value, packet.getData(), recvBuffer.length);

    majStat = gss_process_context_token(&minStat, gssContext, &recvBuffer);

    std::free(recvBuffer.value);

    if(majStat != GSS_S_COMPLETE)
      return;

    signalFinished().emit();
  }
}

}
}
}