/*
* TLS Handshake Hash
* (C) 2004-2006,2011 Jack Lloyd
*
* Released under the terms of the Botan license
*/

#include <botan/internal/tls_handshake_hash.h>
#include <botan/tls_exceptn.h>
#include <botan/libstate.h>
#include <botan/hash.h>
#include <memory>

namespace Botan {

namespace TLS {

void Handshake_Hash::update(Handshake_Type handshake_type,
                            const std::vector<byte>& handshake_msg)
   {
   update(static_cast<byte>(handshake_type));

   const size_t record_length = handshake_msg.size();
   for(size_t i = 0; i != 3; i++)
      update(get_byte<u32bit>(i+1, record_length));

   update(handshake_msg);
   }

/**
* Return a TLS Handshake Hash
*/
secure_vector<byte> Handshake_Hash::final(Protocol_Version version,
                                         const std::string& mac_algo)
   {
   Algorithm_Factory& af = global_state().algorithm_factory();

   std::unique_ptr<HashFunction> hash;

   if(version == Protocol_Version::TLS_V10 || version == Protocol_Version::TLS_V11)
      {
      hash.reset(af.make_hash_function("TLS.Digest.0"));
      }
   else if(version == Protocol_Version::TLS_V12)
      {
      if(mac_algo == "MD5" || mac_algo == "SHA-1" || mac_algo == "SHA-256")
         hash.reset(af.make_hash_function("SHA-256"));
      else
         hash.reset(af.make_hash_function(mac_algo));
      }
   else
      throw TLS_Exception(Alert::PROTOCOL_VERSION,
                          "Unknown version for handshake hashes");

   hash->update(data);
   return hash->final();
   }

/**
* Return a SSLv3 Handshake Hash
*/
secure_vector<byte> Handshake_Hash::final_ssl3(const secure_vector<byte>& secret)
   {
   const byte PAD_INNER = 0x36, PAD_OUTER = 0x5C;

   Algorithm_Factory& af = global_state().algorithm_factory();

   std::unique_ptr<HashFunction> md5(af.make_hash_function("MD5"));
   std::unique_ptr<HashFunction> sha1(af.make_hash_function("SHA-1"));

   md5->update(data);
   sha1->update(data);

   md5->update(secret);
   sha1->update(secret);

   for(size_t i = 0; i != 48; ++i)
      md5->update(PAD_INNER);
   for(size_t i = 0; i != 40; ++i)
      sha1->update(PAD_INNER);

   secure_vector<byte> inner_md5 = md5->final(), inner_sha1 = sha1->final();

   md5->update(secret);
   sha1->update(secret);

   for(size_t i = 0; i != 48; ++i)
      md5->update(PAD_OUTER);
   for(size_t i = 0; i != 40; ++i)
      sha1->update(PAD_OUTER);

   md5->update(inner_md5);
   sha1->update(inner_sha1);

   secure_vector<byte> output;
   output += md5->final();
   output += sha1->final();
   return output;
   }

}

}