/*
   * Copyright 2003-2004, Instant802 Networks, Inc.
   * Copyright 2005-2006, Devicescape Software, Inc.
   *

   * Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
   *

   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */

  #include <linux/kernel.h>

  #include <linux/types.h>

  #include <linux/err.h>

  #include <crypto/aead.h>

  
  #include <net/mac80211.h>

  #include "key.h"

  #include "aes_ccm.h"

  int ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  			      u8 *data, size_t data_len, u8 *mic,
  			      size_t mic_len)

  {

  	struct scatterlist sg[3];

  	struct aead_request *aead_req;
  	int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  	u8 *__aad;

  	aead_req = kzalloc(reqsize + CCM_AAD_LEN, GFP_ATOMIC);
  	if (!aead_req)
  		return -ENOMEM;

  	__aad = (u8 *)aead_req + reqsize;
  	memcpy(__aad, aad, CCM_AAD_LEN);

  	sg_init_table(sg, 3);

  	sg_set_buf(&sg[0], &__aad[2], be16_to_cpup((__be16 *)__aad));

  	sg_set_buf(&sg[1], data, data_len);
  	sg_set_buf(&sg[2], mic, mic_len);

  	aead_request_set_tfm(aead_req, tfm);

  	aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
  	aead_request_set_ad(aead_req, sg[0].length);

  	crypto_aead_encrypt(aead_req);

  	kzfree(aead_req);
  
  	return 0;

  }

  int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,

  			      u8 *data, size_t data_len, u8 *mic,
  			      size_t mic_len)

  {

  	struct scatterlist sg[3];

  	struct aead_request *aead_req;
  	int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  	u8 *__aad;
  	int err;

  	if (data_len == 0)
  		return -EINVAL;

  	aead_req = kzalloc(reqsize + CCM_AAD_LEN, GFP_ATOMIC);
  	if (!aead_req)
  		return -ENOMEM;
  
  	__aad = (u8 *)aead_req + reqsize;
  	memcpy(__aad, aad, CCM_AAD_LEN);

  	sg_init_table(sg, 3);

  	sg_set_buf(&sg[0], &__aad[2], be16_to_cpup((__be16 *)__aad));

  	sg_set_buf(&sg[1], data, data_len);
  	sg_set_buf(&sg[2], mic, mic_len);

  	aead_request_set_tfm(aead_req, tfm);

  	aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
  	aead_request_set_ad(aead_req, sg[0].length);

  	err = crypto_aead_decrypt(aead_req);
  	kzfree(aead_req);
  
  	return err;

  }

  struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[],
  						    size_t key_len,
  						    size_t mic_len)

  {

  	struct crypto_aead *tfm;
  	int err;

  	tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  	if (IS_ERR(tfm))
  		return tfm;

  	err = crypto_aead_setkey(tfm, key, key_len);

  	if (err)
  		goto free_aead;
  	err = crypto_aead_setauthsize(tfm, mic_len);
  	if (err)
  		goto free_aead;
  
  	return tfm;

  free_aead:

  	crypto_free_aead(tfm);
  	return ERR_PTR(err);

  }

  void ieee80211_aes_key_free(struct crypto_aead *tfm)

  {

  	crypto_free_aead(tfm);

  }