src/libstrongswan/plugins/xcbc/xcbc_prf.c

   1 /*
   2  * Copyright (C) 2008 Martin Willi
   3  * Hochschule fuer Technik Rapperswil
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 #include "xcbc_prf.h"
  17
  18 #include "xcbc.h"
  19
  20 typedef struct private_xcbc_prf_t private_xcbc_prf_t;
  21
  22 /**
  23  * Private data of a xcbc_prf_t object.
  24  */
  25 struct private_xcbc_prf_t {
  26
  27         /**
  28          * Public xcbc_prf_t interface.
  29          */
  30         xcbc_prf_t public;
  31
  32         /**
  33          * xcbc to use for generation.
  34          */
  35         xcbc_t *xcbc;
  36 };
  37
  38 METHOD(prf_t, get_bytes, void,
  39         private_xcbc_prf_t *this, chunk_t seed, u_int8_t *buffer)
  40 {
  41         this->xcbc->get_mac(this->xcbc, seed, buffer);
  42 }
  43
  44 METHOD(prf_t, allocate_bytes, void,
  45         private_xcbc_prf_t *this, chunk_t seed, chunk_t *chunk)
  46 {
  47         if (chunk)
  48         {
  49                 *chunk = chunk_alloc(this->xcbc->get_block_size(this->xcbc));
  50                 get_bytes(this, seed, chunk->ptr);
  51         }
  52         else
  53         {
  54                 get_bytes(this, seed, NULL);
  55         }
  56 }
  57
  58 METHOD(prf_t, get_block_size, size_t,
  59         private_xcbc_prf_t *this)
  60 {
  61         return this->xcbc->get_block_size(this->xcbc);
  62 }
  63
  64 METHOD(prf_t, get_key_size, size_t,
  65         private_xcbc_prf_t *this)
  66 {
  67         /* in xcbc, block and key size are always equal */
  68         return this->xcbc->get_block_size(this->xcbc);
  69 }
  70
  71 METHOD(prf_t, set_key, void,
  72         private_xcbc_prf_t *this, chunk_t key)
  73 {
  74         this->xcbc->set_key(this->xcbc, key);
  75 }
  76
  77 METHOD(prf_t, destroy, void,
  78         private_xcbc_prf_t *this)
  79 {
  80         this->xcbc->destroy(this->xcbc);
  81         free(this);
  82 }
  83
  84 /*
  85  * Described in header.
  86  */
  87 xcbc_prf_t *xcbc_prf_create(pseudo_random_function_t algo)
  88 {
  89         private_xcbc_prf_t *this;
  90         xcbc_t *xcbc;
  91
  92         switch (algo)
  93         {
  94                 case PRF_AES128_XCBC:
  95                         xcbc = xcbc_create(ENCR_AES_CBC, 16);
  96                         break;
  97                 default:
  98                         return NULL;
  99         }
 100         if (!xcbc)
 101         {
 102                 return NULL;
 103         }
 104
 105         INIT(this,
 106                 .public.prf = {
 107                         .get_bytes = _get_bytes,
 108                         .allocate_bytes = _allocate_bytes,
 109                         .get_block_size = _get_block_size,
 110                         .get_key_size = _get_key_size,
 111                         .set_key = _set_key,
 112                         .destroy = _destroy,
 113                 },
 114                 .xcbc = xcbc,
 115         );
 116
 117         return &this->public;
 118 }
 119