EstablishCallback.cc

/*
 * Copyright 2003 Michael A. Marsh, Cornell University. All rights reserved.
 * This software is released under the modified BSD license.
 * See the file LICENSE in the top-level directory for details.
 */
//
// $Id: EstablishCallback.cc,v 1.3 2004/05/19 15:56:23 mmarsh Exp $
//
// $Log: EstablishCallback.cc,v $
// Revision 1.3  2004/05/19 15:56:23  mmarsh
// Added copyright and license statements.
//
// Revision 1.2  2003/11/04 22:31:45  mmarsh
// *** empty log message ***
//
//

#include "EstablishCallback.h"
#include "CODEX_Server/ServerState.h"
#include "StateInfo.h"
#include "Message.h"

#include "CODEX_Exceptions/BignumExceptions.h"
#include "CODEX_Server/ServerExceptions.h"

#include "timing.h"

using namespace CODEX_APSS;

EstablishCallback::EstablishCallback( InitActivity* initAct,
                                      unsigned int version,
                                      const SublabelType& label ) :
   m_initAct( initAct ),
   m_version( version ),
   m_label( label ),
   m_completed( false ),
   m_evidence( new EvidenceVector )
{
}

EstablishCallback::~EstablishCallback()
{
   if ( 0 != m_evidence ) delete m_evidence;
}

bool
EstablishCallback::operator()( unsigned int server,
                               CODEX_Quorum::Message* msg )
{
   if ( m_completed )
   {
      if ( 0 != msg ) delete msg;
      return true;
   }

   if ( 0 == msg )
   {
      return false;
   }

   if ( 0 == m_evidence )
   {
      // something's wrong -- disable
      m_completed = true;
      delete msg;
      return false;
   }

#ifdef TIMING
   ActiveTimer.start();
#endif
   CODEX_Server::ServerState* serverState =
      CODEX_Server::ServerState::instance();
   if ( 0 == serverState )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   StateInfo* stateInfo = StateInfo::instance();
   if ( 0 == stateInfo )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   // Unmarshal the message.
   unsigned char* data = (unsigned char*)msg->buffer();
   int length = msg->length();

   if ( length < 2 )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   if ( stateInfo->domain() != data[0] )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }
   ++data;
   --length;

   if ( ( kEstablishedMsg | SignatureMask ) != data[0] )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }
   ++data;
   --length;

   SignedEstablishedMsg signedResponse;
   if ( 0 == signedResponse.unmarshal( 0, &data, length ) )
   {
      delete msg;
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }
   delete msg;

   // Make sure the response is valid.
   const EstablishedMsg& response = signedResponse.message();
   unsigned int srVersion = response.version().value();
   if ( srVersion != m_version )
   {
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   unsigned int srRecipient = response.recipient().value();
   if ( srRecipient != server )
   {
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   if ( response.establisher().value() != serverState->hostNum() )
   {
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   if ( response.sublabel() != m_label )
   {
#ifdef TIMING
      ActiveTimer.stop();
#endif
      return false;
   }

   // Check the signature.
   BIGNUM * digest = 0;
   try
   {
      digest = response.digest( serverState->hashFunc() );
      if ( 0 == digest )
      {
         throw CODEX_Exceptions::BignumNullException( __FILE__ , __LINE__ );
      }
      if ( ! serverState->publicKey(server).verifySignature(
         signedResponse.signature(),
         digest ) )
      {
         throw CODEX_Server::SignatureVerificationFailedException( __FILE__ ,
                                                                   __LINE__ );
      }
      BN_free(digest);
   }
   catch ( ... )
   {
      if ( 0 != digest ) BN_free(digest);
   }

   // Add to the evidence list.
   m_evidence->push_back( signedResponse );

   // Check to see if we have collected enough responses.
   CODEX_Quorum::QuorumSystem* qs = serverState->quorumSystem();
   if ( 0 == qs )
   {
#ifdef TIMING
      ActiveTimer.stop();
#endif
      throw CODEX_Server::NoQuorumSystemException( __FILE__ , __LINE__ );
   }
   if ( m_evidence->size() >= qs->quorumSize() )
   {
      m_initAct->addEvidence( m_label, m_evidence );
      m_evidence = 0;
      m_completed = true;
   }

#ifdef TIMING
   ActiveTimer.stop();
#endif
   return true;
}

void
EstablishCallback::fail()
{
   if ( 0 != m_initAct )
   {
      m_initAct->addFailure();
   }
}

---