/*

* Message Authentication Code base class

* (C) 1999-2008 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/mac.h>

#include <botan/exceptn.h>

#include <botan/scan_name.h>

#include <botan/mem_ops.h>

#if defined(BOTAN_HAS_CBC_MAC)

  #include <botan/cbc_mac.h>

#endif

#if defined(BOTAN_HAS_CMAC)

  #include <botan/cmac.h>

#endif

#if defined(BOTAN_HAS_GMAC)

  #include <botan/gmac.h>

  #include <botan/block_cipher.h>

#endif

#if defined(BOTAN_HAS_HMAC)

  #include <botan/hmac.h>

  #include <botan/hash.h>

#endif

#if defined(BOTAN_HAS_POLY1305)

  #include <botan/poly1305.h>

#endif

#if defined(BOTAN_HAS_SIPHASH)

  #include <botan/siphash.h>

#endif

#if defined(BOTAN_HAS_ANSI_X919_MAC)

  #include <botan/x919_mac.h>

#endif

namespace Botan {

std::unique_ptr<MessageAuthenticationCode>

MessageAuthenticationCode::create(const std::string& algo_spec,

                                  const std::string& provider)

   {

   const SCAN_Name req(algo_spec);

#if defined(BOTAN_HAS_GMAC)

   if(req.algo_name() == "GMAC" && req.arg_count() == 1)

      {

      if(provider.empty() || provider == "base")

         {

         if(auto bc = BlockCipher::create(req.arg(0)))

            return std::unique_ptr<MessageAuthenticationCode>(new GMAC(bc.release()));

         }

      }

#endif

#if defined(BOTAN_HAS_HMAC)

   if(req.algo_name() == "HMAC" && req.arg_count() == 1)

      {

      // TODO OpenSSL

      if(provider.empty() || provider == "base")

         {

         if(auto h = HashFunction::create(req.arg(0)))

            return std::unique_ptr<MessageAuthenticationCode>(new HMAC(h.release()));

         }

      }

#endif

#if defined(BOTAN_HAS_POLY1305)

   if(req.algo_name() == "Poly1305" && req.arg_count() == 0)

      {

      if(provider.empty() || provider == "base")

         return std::unique_ptr<MessageAuthenticationCode>(new Poly1305);

      }

#endif

#if defined(BOTAN_HAS_SIPHASH)

   if(req.algo_name() == "SipHash")

      {

      if(provider.empty() || provider == "base")

         {

         return std::unique_ptr<MessageAuthenticationCode>(

            new SipHash(req.arg_as_integer(0, 2), req.arg_as_integer(1, 4)));

         }

      }

#endif

#if defined(BOTAN_HAS_CMAC)

   if((req.algo_name() == "CMAC" || req.algo_name() == "OMAC") && req.arg_count() == 1)

      {

      // TODO: OpenSSL CMAC

      if(provider.empty() || provider == "base")

         {

         if(auto bc = BlockCipher::create(req.arg(0)))

            return std::unique_ptr<MessageAuthenticationCode>(new CMAC(bc.release()));

         }

      }

#endif

#if defined(BOTAN_HAS_CBC_MAC)

   if(req.algo_name() == "CBC-MAC" && req.arg_count() == 1)

      {

      if(provider.empty() || provider == "base")

         {

         if(auto bc = BlockCipher::create(req.arg(0)))

            return std::unique_ptr<MessageAuthenticationCode>(new CBC_MAC(bc.release()));

         }

      }

#endif

#if defined(BOTAN_HAS_ANSI_X919_MAC)

   if(req.algo_name() == "X9.19-MAC")

      {

      if(provider.empty() || provider == "base")

         {

         return std::unique_ptr<MessageAuthenticationCode>(new ANSI_X919_MAC);

         }

      }

#endif

   BOTAN_UNUSED(req);

   BOTAN_UNUSED(provider);

   return nullptr;

   }

std::vector<std::string>

MessageAuthenticationCode::providers(const std::string& algo_spec)

   {

   return probe_providers_of<MessageAuthenticationCode>(algo_spec, {"base", "openssl"});

   }

//static

std::unique_ptr<MessageAuthenticationCode>

MessageAuthenticationCode::create_or_throw(const std::string& algo,

                                           const std::string& provider)

   {

   if(auto mac = MessageAuthenticationCode::create(algo, provider))

      {

      return mac;

      }

   throw Lookup_Error("MAC", algo, provider);

   }

void MessageAuthenticationCode::start_msg(const uint8_t nonce[], size_t nonce_len)

   {

   BOTAN_UNUSED(nonce);

   if(nonce_len > 0)

      throw Invalid_IV_Length(name(), nonce_len);

   }

/*

* Default (deterministic) MAC verification operation

*/

bool MessageAuthenticationCode::verify_mac(const uint8_t mac[], size_t length)

   {

   secure_vector<uint8_t> our_mac = final();

   if(our_mac.size() != length)

      return false;

   return constant_time_compare(our_mac.data(), mac, length);

   }

}