src/libstrongswan/crypto/iv/iv_gen_seq.c

   1 /*
   2  * Copyright (C) 2013 Tobias Brunner
   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 "iv_gen_seq.h"
  17
  18 typedef struct private_iv_gen_t private_iv_gen_t;
  19
  20 /**
  21  * Private data of an iv_gen_t object.
  22  */
  23 struct private_iv_gen_t {
  24
  25         /**
  26          * Public iv_gen_t interface.
  27          */
  28         iv_gen_t public;
  29 };
  30
  31 METHOD(iv_gen_t, get_iv, bool,
  32         private_iv_gen_t *this, u_int64_t seq, size_t size, u_int8_t *buffer)
  33 {
  34         u_int8_t iv[sizeof(u_int64_t)];
  35         size_t len = size;
  36
  37         if (len > sizeof(u_int64_t))
  38         {
  39                 len = sizeof(u_int64_t);
  40                 memset(buffer, 0, size - len);
  41         }
  42         htoun64(iv, seq);
  43         memcpy(buffer + size - len, iv + sizeof(u_int64_t) - len, len);
  44         return TRUE;
  45 }
  46
  47 METHOD(iv_gen_t, allocate_iv, bool,
  48         private_iv_gen_t *this, u_int64_t seq, size_t size, chunk_t *chunk)
  49 {
  50         *chunk = chunk_alloc(size);
  51         if (!get_iv(this, seq, chunk->len, chunk->ptr))
  52         {
  53                 chunk_free(chunk);
  54                 return FALSE;
  55         }
  56         return TRUE;
  57 }
  58
  59 METHOD(iv_gen_t, destroy, void,
  60         private_iv_gen_t *this)
  61 {
  62         free(this);
  63 }
  64
  65 iv_gen_t *iv_gen_seq_create()
  66 {
  67         private_iv_gen_t *this;
  68
  69         INIT(this,
  70                 .public = {
  71                         .get_iv = _get_iv,
  72                         .allocate_iv = _allocate_iv,
  73                         .destroy = _destroy,
  74                 },
  75         );
  76
  77         return &this->public;
  78 }