programs/charon/lib/crypto/prfs/hmac_prf.c

   1 /**
   2  * @file hmac_prf.c
   3  *
   4  * @brief Implementation for hmac_prf_t.
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005 Jan Hutter, Martin Willi
  10  * Hochschule fuer Technik Rapperswil
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by the
  14  * Free Software Foundation; either version 2 of the License, or (at your
  15  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  */
  22
  23 #include "hmac_prf.h"
  24
  25 #include <crypto/hmac.h>
  26
  27
  28 typedef struct private_hmac_prf_t private_hmac_prf_t;
  29
  30 /**
  31  * Private data of a hma_prf_t object.
  32  */
  33 struct private_hmac_prf_t {
  34         /**
  35          * Public hmac_prf_t interface.
  36          */
  37         hmac_prf_t public;
  38
  39         /**
  40          * Hmac to use for generation.
  41          */
  42         hmac_t *hmac;
  43 };
  44
  45 /**
  46  * Implementation of prf_t.get_bytes.
  47  */
  48 static void get_bytes(private_hmac_prf_t *this, chunk_t seed, u_int8_t *buffer)
  49 {
  50         this->hmac->get_mac(this->hmac, seed, buffer);
  51 }
  52
  53 /**
  54  * Implementation of prf_t.allocate_bytes.
  55  */
  56 static void allocate_bytes(private_hmac_prf_t *this, chunk_t seed, chunk_t *chunk)
  57 {
  58         this->hmac->allocate_mac(this->hmac, seed, chunk);
  59 }
  60
  61 /**
  62  * Implementation of prf_t.get_block_size.
  63  */
  64 static size_t get_block_size(private_hmac_prf_t *this)
  65 {
  66         return this->hmac->get_block_size(this->hmac);
  67 }
  68
  69 /**
  70  * Implementation of prf_t.get_block_size.
  71  */
  72 static size_t get_key_size(private_hmac_prf_t *this)
  73 {
  74         /* for HMAC prfs, IKEv2 uses block size as key size */
  75         return this->hmac->get_block_size(this->hmac);
  76 }
  77
  78 /**
  79  * Implementation of prf_t.set_key.
  80  */
  81 static void set_key(private_hmac_prf_t *this, chunk_t key)
  82 {
  83         this->hmac->set_key(this->hmac, key);
  84 }
  85
  86 /**
  87  * Implementation of prf_t.destroy.
  88  */
  89 static void destroy(private_hmac_prf_t *this)
  90 {
  91         free(this);
  92         this->hmac->destroy(this->hmac);
  93 }
  94
  95 /*
  96  * Described in header.
  97  */
  98 hmac_prf_t *hmac_prf_create(hash_algorithm_t hash_algorithm)
  99 {
 100         private_hmac_prf_t *this = malloc_thing(private_hmac_prf_t);
 101
 102         this->public.prf_interface.get_bytes = (void (*) (prf_t *,chunk_t,u_int8_t*))get_bytes;
 103         this->public.prf_interface.allocate_bytes = (void (*) (prf_t*,chunk_t,chunk_t*))allocate_bytes;
 104         this->public.prf_interface.get_block_size = (size_t (*) (prf_t*))get_block_size;
 105         this->public.prf_interface.get_key_size = (size_t (*) (prf_t*))get_key_size;
 106         this->public.prf_interface.set_key = (void (*) (prf_t *,chunk_t))set_key;
 107         this->public.prf_interface.destroy = (void (*) (prf_t *))destroy;
 108
 109         this->hmac = hmac_create(hash_algorithm);
 110         if (this->hmac == NULL)
 111         {
 112                 free(this);
 113                 return NULL;
 114         }
 115
 116         return &(this->public);
 117 }