Source/charon/transforms/prfs/prf_hmac.c

   1 /**
   2  * @file prf_hmac.c
   3  *
   4  * @brief Implementation of prf_t interface using the
   5  * a HMAC algorithm. This simply wraps a hmac in a prf.
   6  *
   7  */
   8
   9 /*
  10  * Copyright (C) 2005 Jan Hutter, Martin Willi
  11  * Hochschule fuer Technik Rapperswil
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the
  15  * Free Software Foundation; either version 2 of the License, or (at your
  16  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  17  *
  18  * This program is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  20  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  21  * for more details.
  22  */
  23
  24 #include "prf_hmac.h"
  25
  26 #include "../../utils/allocator.h"
  27 #include "../hmac.h"
  28
  29 typedef struct private_prf_hmac_s private_prf_hmac_t;
  30
  31 struct private_prf_hmac_s {
  32         /**
  33          * public interface for this prf
  34          */
  35         prf_hmac_t public;
  36
  37         /**
  38          * hmac to use for generation
  39          */
  40         hmac_t *hmac;
  41 };
  42
  43 /**
  44  * implementation of prf_t.get_bytes
  45  */
  46 static status_t get_bytes(private_prf_hmac_t *this, chunk_t seed, u_int8_t *buffer)
  47 {
  48         return this->hmac->get_mac(this->hmac, seed, buffer);
  49 }
  50
  51 /**
  52  * implementation of prf_t.allocate_bytes
  53  */
  54 static status_t allocate_bytes(private_prf_hmac_t *this, chunk_t seed, chunk_t *chunk)
  55 {
  56         return this->hmac->allocate_mac(this->hmac, seed, chunk);
  57 }
  58
  59 /**
  60  * implementation of prf_t.get_block_size
  61  */
  62 static size_t get_block_size(private_prf_hmac_t *this)
  63 {
  64         return this->hmac->get_block_size(this->hmac);
  65 }
  66
  67 /**
  68  * implementation of prf_t.set_key
  69  */
  70 static status_t set_key(private_prf_hmac_t *this, chunk_t key)
  71 {
  72         this->hmac->set_key(this->hmac, key);
  73         return SUCCESS;
  74 }
  75
  76 /**
  77  * implementation of prf_t.destroy
  78  */
  79 static status_t destroy(private_prf_hmac_t *this)
  80 {
  81         allocator_free(this);
  82         this->hmac->destroy(this->hmac);
  83         return SUCCESS;
  84 }
  85
  86 /*
  87  * Described in header
  88  */
  89 prf_hmac_t *prf_hmac_create(hash_algorithm_t hash_algorithm)
  90 {
  91         private_prf_hmac_t *this = allocator_alloc_thing(private_prf_hmac_t);
  92
  93         if (this == NULL)
  94         {
  95                 return NULL;
  96         }
  97
  98         this->public.prf_interface.get_bytes = (status_t (*) (prf_t *,chunk_t,u_int8_t*))get_bytes;
  99         this->public.prf_interface.allocate_bytes = (status_t (*) (prf_t*,chunk_t,chunk_t*))allocate_bytes;
 100         this->public.prf_interface.get_block_size = (size_t (*) (prf_t*))get_block_size;
 101         this->public.prf_interface.set_key = (status_t (*) (prf_t *,chunk_t))set_key;
 102         this->public.prf_interface.destroy = (status_t (*) (prf_t *))destroy;
 103
 104         this->hmac = hmac_create(HASH_SHA1);
 105         if (this->hmac == NULL)
 106         {
 107                 allocator_free(this);
 108                 return NULL;
 109         }
 110
 111         return &(this->public);
 112 }