/*
   * Software async crypto daemon.
   *
   * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   *
   * 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 <crypto/algapi.h>
  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/kthread.h>
  #include <linux/list.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/scatterlist.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  
  #define CRYPTD_MAX_QLEN 100
  
  struct cryptd_state {
  	spinlock_t lock;
  	struct mutex mutex;
  	struct crypto_queue queue;
  	struct task_struct *task;
  };
  
  struct cryptd_instance_ctx {
  	struct crypto_spawn spawn;
  	struct cryptd_state *state;
  };
  
  struct cryptd_blkcipher_ctx {
  	struct crypto_blkcipher *child;
  };
  
  struct cryptd_blkcipher_request_ctx {
  	crypto_completion_t complete;
  };
  
  
  static inline struct cryptd_state *cryptd_get_state(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
  	return ictx->state;
  }
  
  static int cryptd_blkcipher_setkey(struct crypto_ablkcipher *parent,
  				   const u8 *key, unsigned int keylen)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(parent);
  	struct crypto_blkcipher *child = ctx->child;
  	int err;
  
  	crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_blkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
  					  CRYPTO_TFM_REQ_MASK);
  	err = crypto_blkcipher_setkey(child, key, keylen);
  	crypto_ablkcipher_set_flags(parent, crypto_blkcipher_get_flags(child) &
  					    CRYPTO_TFM_RES_MASK);
  	return err;
  }
  
  static void cryptd_blkcipher_crypt(struct ablkcipher_request *req,
  				   struct crypto_blkcipher *child,
  				   int err,
  				   int (*crypt)(struct blkcipher_desc *desc,
  						struct scatterlist *dst,
  						struct scatterlist *src,
  						unsigned int len))
  {
  	struct cryptd_blkcipher_request_ctx *rctx;
  	struct blkcipher_desc desc;
  
  	rctx = ablkcipher_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS)) {
  		rctx->complete(&req->base, err);
  		return;
  	}
  
  	desc.tfm = child;
  	desc.info = req->info;
  	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  
  	err = crypt(&desc, req->dst, req->src, req->nbytes);
  
  	req->base.complete = rctx->complete;
  
  	local_bh_disable();
  	req->base.complete(&req->base, err);
  	local_bh_enable();
  }
  
  static void cryptd_blkcipher_encrypt(struct crypto_async_request *req, int err)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
  	struct crypto_blkcipher *child = ctx->child;
  
  	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
  			       crypto_blkcipher_crt(child)->encrypt);
  }
  
  static void cryptd_blkcipher_decrypt(struct crypto_async_request *req, int err)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
  	struct crypto_blkcipher *child = ctx->child;
  
  	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
  			       crypto_blkcipher_crt(child)->decrypt);
  }
  
  static int cryptd_blkcipher_enqueue(struct ablkcipher_request *req,
  				    crypto_completion_t complete)
  {
  	struct cryptd_blkcipher_request_ctx *rctx = ablkcipher_request_ctx(req);
  	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
  	struct cryptd_state *state =
  		cryptd_get_state(crypto_ablkcipher_tfm(tfm));
  	int err;
  
  	rctx->complete = req->base.complete;
  	req->base.complete = complete;
  
  	spin_lock_bh(&state->lock);

  	err = ablkcipher_enqueue_request(&state->queue, req);

  	spin_unlock_bh(&state->lock);
  
  	wake_up_process(state->task);
  	return err;
  }
  
  static int cryptd_blkcipher_encrypt_enqueue(struct ablkcipher_request *req)
  {
  	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_encrypt);
  }
  
  static int cryptd_blkcipher_decrypt_enqueue(struct ablkcipher_request *req)
  {
  	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_decrypt);
  }
  
  static int cryptd_blkcipher_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
  	struct crypto_spawn *spawn = &ictx->spawn;
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
  	struct crypto_blkcipher *cipher;
  
  	cipher = crypto_spawn_blkcipher(spawn);
  	if (IS_ERR(cipher))
  		return PTR_ERR(cipher);
  
  	ctx->child = cipher;
  	tfm->crt_ablkcipher.reqsize =
  		sizeof(struct cryptd_blkcipher_request_ctx);
  	return 0;
  }
  
  static void cryptd_blkcipher_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
  	struct cryptd_state *state = cryptd_get_state(tfm);
  	int active;
  
  	mutex_lock(&state->mutex);

  	active = ablkcipher_tfm_in_queue(&state->queue,
  					 __crypto_ablkcipher_cast(tfm));

  	mutex_unlock(&state->mutex);
  
  	BUG_ON(active);
  
  	crypto_free_blkcipher(ctx->child);
  }
  
  static struct crypto_instance *cryptd_alloc_instance(struct crypto_alg *alg,
  						     struct cryptd_state *state)
  {
  	struct crypto_instance *inst;
  	struct cryptd_instance_ctx *ctx;
  	int err;
  
  	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);

  	if (!inst) {
  		inst = ERR_PTR(-ENOMEM);

  		goto out;

  	}

  
  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "cryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
  		goto out_free_inst;
  
  	ctx = crypto_instance_ctx(inst);
  	err = crypto_init_spawn(&ctx->spawn, alg, inst,
  				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
  	if (err)
  		goto out_free_inst;
  
  	ctx->state = state;
  
  	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  
  	inst->alg.cra_priority = alg->cra_priority + 50;
  	inst->alg.cra_blocksize = alg->cra_blocksize;
  	inst->alg.cra_alignmask = alg->cra_alignmask;
  
  out:
  	return inst;
  
  out_free_inst:
  	kfree(inst);
  	inst = ERR_PTR(err);
  	goto out;
  }
  
  static struct crypto_instance *cryptd_alloc_blkcipher(
  	struct rtattr **tb, struct cryptd_state *state)
  {
  	struct crypto_instance *inst;
  	struct crypto_alg *alg;
  
  	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_BLKCIPHER,

  				  CRYPTO_ALG_TYPE_MASK);

  	if (IS_ERR(alg))

  		return ERR_CAST(alg);

  
  	inst = cryptd_alloc_instance(alg, state);
  	if (IS_ERR(inst))
  		goto out_put_alg;

  	inst->alg.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC;

  	inst->alg.cra_type = &crypto_ablkcipher_type;
  
  	inst->alg.cra_ablkcipher.ivsize = alg->cra_blkcipher.ivsize;
  	inst->alg.cra_ablkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
  	inst->alg.cra_ablkcipher.max_keysize = alg->cra_blkcipher.max_keysize;

  	inst->alg.cra_ablkcipher.geniv = alg->cra_blkcipher.geniv;

  	inst->alg.cra_ctxsize = sizeof(struct cryptd_blkcipher_ctx);
  
  	inst->alg.cra_init = cryptd_blkcipher_init_tfm;
  	inst->alg.cra_exit = cryptd_blkcipher_exit_tfm;
  
  	inst->alg.cra_ablkcipher.setkey = cryptd_blkcipher_setkey;
  	inst->alg.cra_ablkcipher.encrypt = cryptd_blkcipher_encrypt_enqueue;
  	inst->alg.cra_ablkcipher.decrypt = cryptd_blkcipher_decrypt_enqueue;

  out_put_alg:
  	crypto_mod_put(alg);
  	return inst;
  }
  
  static struct cryptd_state state;
  
  static struct crypto_instance *cryptd_alloc(struct rtattr **tb)
  {
  	struct crypto_attr_type *algt;
  
  	algt = crypto_get_attr_type(tb);
  	if (IS_ERR(algt))

  		return ERR_CAST(algt);

  
  	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
  	case CRYPTO_ALG_TYPE_BLKCIPHER:
  		return cryptd_alloc_blkcipher(tb, &state);
  	}
  
  	return ERR_PTR(-EINVAL);
  }
  
  static void cryptd_free(struct crypto_instance *inst)
  {
  	struct cryptd_instance_ctx *ctx = crypto_instance_ctx(inst);
  
  	crypto_drop_spawn(&ctx->spawn);
  	kfree(inst);
  }
  
  static struct crypto_template cryptd_tmpl = {
  	.name = "cryptd",
  	.alloc = cryptd_alloc,
  	.free = cryptd_free,
  	.module = THIS_MODULE,
  };
  
  static inline int cryptd_create_thread(struct cryptd_state *state,
  				       int (*fn)(void *data), const char *name)
  {
  	spin_lock_init(&state->lock);
  	mutex_init(&state->mutex);
  	crypto_init_queue(&state->queue, CRYPTD_MAX_QLEN);

  	state->task = kthread_run(fn, state, name);

  	if (IS_ERR(state->task))
  		return PTR_ERR(state->task);
  
  	return 0;
  }
  
  static inline void cryptd_stop_thread(struct cryptd_state *state)
  {
  	BUG_ON(state->queue.qlen);
  	kthread_stop(state->task);
  }
  
  static int cryptd_thread(void *data)
  {
  	struct cryptd_state *state = data;
  	int stop;

  	current->flags |= PF_NOFREEZE;

  	do {
  		struct crypto_async_request *req, *backlog;
  
  		mutex_lock(&state->mutex);
  		__set_current_state(TASK_INTERRUPTIBLE);
  
  		spin_lock_bh(&state->lock);
  		backlog = crypto_get_backlog(&state->queue);
  		req = crypto_dequeue_request(&state->queue);
  		spin_unlock_bh(&state->lock);
  
  		stop = kthread_should_stop();
  
  		if (stop || req) {
  			__set_current_state(TASK_RUNNING);
  			if (req) {
  				if (backlog)
  					backlog->complete(backlog,
  							  -EINPROGRESS);
  				req->complete(req, 0);
  			}
  		}
  
  		mutex_unlock(&state->mutex);
  
  		schedule();
  	} while (!stop);
  
  	return 0;
  }
  
  static int __init cryptd_init(void)
  {
  	int err;
  
  	err = cryptd_create_thread(&state, cryptd_thread, "cryptd");
  	if (err)
  		return err;
  
  	err = crypto_register_template(&cryptd_tmpl);
  	if (err)
  		kthread_stop(state.task);
  
  	return err;
  }
  
  static void __exit cryptd_exit(void)
  {
  	cryptd_stop_thread(&state);
  	crypto_unregister_template(&cryptd_tmpl);
  }
  
  module_init(cryptd_init);
  module_exit(cryptd_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Software async crypto daemon");