/*
   * Scatterlist Cryptographic API.
   *
   * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   * Copyright (c) 2002 David S. Miller (davem@redhat.com)

   * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>

   *
   * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>

   * and Nettle, by Niels Möller.

   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option) 
   * any later version.
   *
   */

  #include <linux/err.h>

  #include <linux/errno.h>

  #include <linux/kernel.h>

  #include <linux/kmod.h>

  #include <linux/module.h>

  #include <linux/param.h>

  #include <linux/sched.h>

  #include <linux/slab.h>

  #include <linux/string.h>

  #include "internal.h"
  
  LIST_HEAD(crypto_alg_list);

  EXPORT_SYMBOL_GPL(crypto_alg_list);

  DECLARE_RWSEM(crypto_alg_sem);

  EXPORT_SYMBOL_GPL(crypto_alg_sem);

  BLOCKING_NOTIFIER_HEAD(crypto_chain);
  EXPORT_SYMBOL_GPL(crypto_chain);

  static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)

  {

  	atomic_inc(&alg->cra_refcnt);
  	return alg;
  }

  struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)

  {
  	return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;

  }

  EXPORT_SYMBOL_GPL(crypto_mod_get);

  void crypto_mod_put(struct crypto_alg *alg)

  {

  	struct module *module = alg->cra_module;

  	crypto_alg_put(alg);

  	module_put(module);

  }

  EXPORT_SYMBOL_GPL(crypto_mod_put);

  struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, u32 mask)

  {
  	struct crypto_alg *q, *alg = NULL;

  	int best = -2;

  	list_for_each_entry(q, &crypto_alg_list, cra_list) {

  		int exact, fuzzy;

  		if (crypto_is_moribund(q))
  			continue;

  		if ((q->cra_flags ^ type) & mask)
  			continue;
  
  		if (crypto_is_larval(q) &&
  		    ((struct crypto_larval *)q)->mask != mask)
  			continue;

  		exact = !strcmp(q->cra_driver_name, name);
  		fuzzy = !strcmp(q->cra_name, name);
  		if (!exact && !(fuzzy && q->cra_priority > best))
  			continue;

  		if (unlikely(!crypto_mod_get(q)))

  			continue;
  
  		best = q->cra_priority;
  		if (alg)

  			crypto_mod_put(alg);

  		alg = q;
  
  		if (exact)

  			break;

  	}

  
  	return alg;
  }
  EXPORT_SYMBOL_GPL(__crypto_alg_lookup);
  
  static void crypto_larval_destroy(struct crypto_alg *alg)
  {
  	struct crypto_larval *larval = (void *)alg;
  
  	BUG_ON(!crypto_is_larval(alg));
  	if (larval->adult)
  		crypto_mod_put(larval->adult);
  	kfree(larval);
  }

  static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type,
  					      u32 mask)

  {
  	struct crypto_alg *alg;
  	struct crypto_larval *larval;
  
  	larval = kzalloc(sizeof(*larval), GFP_KERNEL);
  	if (!larval)

  		return ERR_PTR(-ENOMEM);

  	larval->mask = mask;
  	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;

  	larval->alg.cra_priority = -1;
  	larval->alg.cra_destroy = crypto_larval_destroy;
  
  	atomic_set(&larval->alg.cra_refcnt, 2);
  	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
  	init_completion(&larval->completion);
  
  	down_write(&crypto_alg_sem);

  	alg = __crypto_alg_lookup(name, type, mask);

  	if (!alg) {
  		alg = &larval->alg;
  		list_add(&alg->cra_list, &crypto_alg_list);
  	}
  	up_write(&crypto_alg_sem);
  
  	if (alg != &larval->alg)
  		kfree(larval);
  
  	return alg;
  }

  void crypto_larval_kill(struct crypto_alg *alg)

  {
  	struct crypto_larval *larval = (void *)alg;
  
  	down_write(&crypto_alg_sem);
  	list_del(&alg->cra_list);
  	up_write(&crypto_alg_sem);

  	complete_all(&larval->completion);

  	crypto_alg_put(alg);
  }

  EXPORT_SYMBOL_GPL(crypto_larval_kill);

  
  static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
  {
  	struct crypto_larval *larval = (void *)alg;
  
  	wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
  	alg = larval->adult;

  	if (alg) {
  		if (!crypto_mod_get(alg))
  			alg = ERR_PTR(-EAGAIN);
  	} else
  		alg = ERR_PTR(-ENOENT);

  	crypto_mod_put(&larval->alg);
  
  	return alg;
  }

  static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
  					    u32 mask)

  {
  	struct crypto_alg *alg;

  	down_read(&crypto_alg_sem);

  	alg = __crypto_alg_lookup(name, type, mask);

  	up_read(&crypto_alg_sem);

  	return alg;
  }

  struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)

  {

  	struct crypto_alg *alg;

  	if (!name)
  		return ERR_PTR(-ENOENT);
  
  	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);

  	type &= mask;
  
  	alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
  				      name);

  	if (alg)
  		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;

  	return crypto_larval_alloc(name, type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_larval_lookup);
  
  struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
  {
  	struct crypto_alg *alg;
  	struct crypto_alg *larval;
  	int ok;
  
  	larval = crypto_larval_lookup(name, type, mask);

  	if (IS_ERR(larval) || !crypto_is_larval(larval))

  		return larval;

  	ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
  	if (ok == NOTIFY_DONE) {
  		request_module("cryptomgr");
  		ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
  	}
  
  	if (ok == NOTIFY_STOP)

  		alg = crypto_larval_wait(larval);
  	else {
  		crypto_mod_put(larval);

  		alg = ERR_PTR(-ENOENT);

  	}
  	crypto_larval_kill(larval);
  	return alg;

  }

  EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);

  static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)

  {

  	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;

  	if (type_obj)
  		return type_obj->init(tfm, type, mask);

  	switch (crypto_tfm_alg_type(tfm)) {
  	case CRYPTO_ALG_TYPE_CIPHER:
  		return crypto_init_cipher_ops(tfm);
  		
  	case CRYPTO_ALG_TYPE_DIGEST:
  		return crypto_init_digest_ops(tfm);
  		
  	case CRYPTO_ALG_TYPE_COMPRESS:
  		return crypto_init_compress_ops(tfm);
  	
  	default:
  		break;
  	}
  	
  	BUG();
  	return -EINVAL;
  }
  
  static void crypto_exit_ops(struct crypto_tfm *tfm)
  {

  	const struct crypto_type *type = tfm->__crt_alg->cra_type;
  
  	if (type) {
  		if (type->exit)
  			type->exit(tfm);
  		return;
  	}

  	switch (crypto_tfm_alg_type(tfm)) {
  	case CRYPTO_ALG_TYPE_CIPHER:
  		crypto_exit_cipher_ops(tfm);
  		break;
  		
  	case CRYPTO_ALG_TYPE_DIGEST:
  		crypto_exit_digest_ops(tfm);
  		break;
  		
  	case CRYPTO_ALG_TYPE_COMPRESS:
  		crypto_exit_compress_ops(tfm);
  		break;
  	
  	default:
  		BUG();
  		
  	}
  }

  static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)

  {

  	const struct crypto_type *type_obj = alg->cra_type;

  	unsigned int len;

  	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);

  	if (type_obj)
  		return len + type_obj->ctxsize(alg, type, mask);

  	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
  	default:
  		BUG();
  
  	case CRYPTO_ALG_TYPE_CIPHER:

  		len += crypto_cipher_ctxsize(alg);

  		break;
  		
  	case CRYPTO_ALG_TYPE_DIGEST:

  		len += crypto_digest_ctxsize(alg);

  		break;
  		
  	case CRYPTO_ALG_TYPE_COMPRESS:

  		len += crypto_compress_ctxsize(alg);

  		break;
  	}

  	return len;

  }

  void crypto_shoot_alg(struct crypto_alg *alg)
  {
  	down_write(&crypto_alg_sem);
  	alg->cra_flags |= CRYPTO_ALG_DYING;
  	up_write(&crypto_alg_sem);
  }
  EXPORT_SYMBOL_GPL(crypto_shoot_alg);

  struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
  				      u32 mask)

  {
  	struct crypto_tfm *tfm = NULL;

  	unsigned int tfm_size;

  	int err = -ENOMEM;

  	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);

  	tfm = kzalloc(tfm_size, GFP_KERNEL);

  	if (tfm == NULL)

  		goto out_err;

  	tfm->__crt_alg = alg;

  	err = crypto_init_ops(tfm, type, mask);

  	if (err)

  		goto out_free_tfm;

  	if (alg->cra_init && (err = alg->cra_init(tfm))) {
  		if (err == -EAGAIN)
  			crypto_shoot_alg(alg);

  		goto cra_init_failed;

  	}

  
  	goto out;

  cra_init_failed:
  	crypto_exit_ops(tfm);

  out_free_tfm:
  	kfree(tfm);

  out_err:

  	tfm = ERR_PTR(err);

  out:
  	return tfm;
  }

  EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);

  /*
   *	crypto_alloc_base - Locate algorithm and allocate transform
   *	@alg_name: Name of algorithm
   *	@type: Type of algorithm
   *	@mask: Mask for type comparison
   *
   *	crypto_alloc_base() will first attempt to locate an already loaded
   *	algorithm.  If that fails and the kernel supports dynamically loadable
   *	modules, it will then attempt to load a module of the same name or
   *	alias.  If that fails it will send a query to any loaded crypto manager
   *	to construct an algorithm on the fly.  A refcount is grabbed on the
   *	algorithm which is then associated with the new transform.
   *
   *	The returned transform is of a non-determinate type.  Most people
   *	should use one of the more specific allocation functions such as
   *	crypto_alloc_blkcipher.
   *
   *	In case of error the return value is an error pointer.
   */
  struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
  {
  	struct crypto_tfm *tfm;
  	int err;
  
  	for (;;) {
  		struct crypto_alg *alg;
  
  		alg = crypto_alg_mod_lookup(alg_name, type, mask);

  		if (IS_ERR(alg)) {
  			err = PTR_ERR(alg);

  			goto err;

  		}

  		tfm = __crypto_alloc_tfm(alg, type, mask);

  		if (!IS_ERR(tfm))

  			return tfm;

  
  		crypto_mod_put(alg);
  		err = PTR_ERR(tfm);
  
  err:
  		if (err != -EAGAIN)
  			break;
  		if (signal_pending(current)) {
  			err = -EINTR;
  			break;
  		}

  	}

  	return ERR_PTR(err);

  }
  EXPORT_SYMBOL_GPL(crypto_alloc_base);
   
  /*
   *	crypto_free_tfm - Free crypto transform
   *	@tfm: Transform to free
   *
   *	crypto_free_tfm() frees up the transform and any associated resources,
   *	then drops the refcount on the associated algorithm.
   */

  void crypto_free_tfm(struct crypto_tfm *tfm)
  {

  	struct crypto_alg *alg;
  	int size;
  
  	if (unlikely(!tfm))
  		return;
  
  	alg = tfm->__crt_alg;
  	size = sizeof(*tfm) + alg->cra_ctxsize;

  	if (alg->cra_exit)
  		alg->cra_exit(tfm);

  	crypto_exit_ops(tfm);

  	crypto_mod_put(alg);

  	memset(tfm, 0, size);
  	kfree(tfm);
  }

  EXPORT_SYMBOL_GPL(crypto_free_tfm);

  
  int crypto_has_alg(const char *name, u32 type, u32 mask)
  {
  	int ret = 0;
  	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
  	
  	if (!IS_ERR(alg)) {
  		crypto_mod_put(alg);
  		ret = 1;
  	}
  	
  	return ret;
  }
  EXPORT_SYMBOL_GPL(crypto_has_alg);

  
  MODULE_DESCRIPTION("Cryptographic core API");
  MODULE_LICENSE("GPL");