/*
   * pcrypt - Parallel crypto wrapper.
   *
   * Copyright (C) 2009 secunet Security Networks AG
   * Copyright (C) 2009 Steffen Klassert <steffen.klassert@secunet.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
   */
  
  #include <crypto/algapi.h>
  #include <crypto/internal/aead.h>
  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/slab.h>

  #include <linux/notifier.h>

  #include <linux/kobject.h>

  #include <linux/cpu.h>

  #include <crypto/pcrypt.h>

  struct padata_pcrypt {

  	struct padata_instance *pinst;
  	struct workqueue_struct *wq;
  
  	/*
  	 * Cpumask for callback CPUs. It should be
  	 * equal to serial cpumask of corresponding padata instance,
  	 * so it is updated when padata notifies us about serial
  	 * cpumask change.
  	 *
  	 * cb_cpumask is protected by RCU. This fact prevents us from
  	 * using cpumask_var_t directly because the actual type of
  	 * cpumsak_var_t depends on kernel configuration(particularly on
  	 * CONFIG_CPUMASK_OFFSTACK macro). Depending on the configuration
  	 * cpumask_var_t may be either a pointer to the struct cpumask
  	 * or a variable allocated on the stack. Thus we can not safely use
  	 * cpumask_var_t with RCU operations such as rcu_assign_pointer or
  	 * rcu_dereference. So cpumask_var_t is wrapped with struct
  	 * pcrypt_cpumask which makes possible to use it with RCU.
  	 */
  	struct pcrypt_cpumask {
  		cpumask_var_t mask;
  	} *cb_cpumask;
  	struct notifier_block nblock;
  };

  static struct padata_pcrypt pencrypt;
  static struct padata_pcrypt pdecrypt;

  static struct kset           *pcrypt_kset;

  
  struct pcrypt_instance_ctx {
  	struct crypto_spawn spawn;
  	unsigned int tfm_count;
  };
  
  struct pcrypt_aead_ctx {
  	struct crypto_aead *child;
  	unsigned int cb_cpu;
  };
  
  static int pcrypt_do_parallel(struct padata_priv *padata, unsigned int *cb_cpu,

  			      struct padata_pcrypt *pcrypt)

  {
  	unsigned int cpu_index, cpu, i;

  	struct pcrypt_cpumask *cpumask;

  
  	cpu = *cb_cpu;

  	rcu_read_lock_bh();
  	cpumask = rcu_dereference(pcrypt->cb_cpumask);
  	if (cpumask_test_cpu(cpu, cpumask->mask))

  			goto out;

  	if (!cpumask_weight(cpumask->mask))
  			goto out;

  	cpu_index = cpu % cpumask_weight(cpumask->mask);

  	cpu = cpumask_first(cpumask->mask);

  	for (i = 0; i < cpu_index; i++)

  		cpu = cpumask_next(cpu, cpumask->mask);

  
  	*cb_cpu = cpu;
  
  out:

  	rcu_read_unlock_bh();
  	return padata_do_parallel(pcrypt->pinst, padata, cpu);

  }
  
  static int pcrypt_aead_setkey(struct crypto_aead *parent,
  			      const u8 *key, unsigned int keylen)
  {
  	struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);
  
  	return crypto_aead_setkey(ctx->child, key, keylen);
  }
  
  static int pcrypt_aead_setauthsize(struct crypto_aead *parent,
  				   unsigned int authsize)
  {
  	struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);
  
  	return crypto_aead_setauthsize(ctx->child, authsize);
  }
  
  static void pcrypt_aead_serial(struct padata_priv *padata)
  {
  	struct pcrypt_request *preq = pcrypt_padata_request(padata);
  	struct aead_request *req = pcrypt_request_ctx(preq);
  
  	aead_request_complete(req->base.data, padata->info);
  }
  
  static void pcrypt_aead_giv_serial(struct padata_priv *padata)
  {
  	struct pcrypt_request *preq = pcrypt_padata_request(padata);
  	struct aead_givcrypt_request *req = pcrypt_request_ctx(preq);
  
  	aead_request_complete(req->areq.base.data, padata->info);
  }
  
  static void pcrypt_aead_done(struct crypto_async_request *areq, int err)
  {
  	struct aead_request *req = areq->data;
  	struct pcrypt_request *preq = aead_request_ctx(req);
  	struct padata_priv *padata = pcrypt_request_padata(preq);
  
  	padata->info = err;
  	req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
  
  	padata_do_serial(padata);
  }
  
  static void pcrypt_aead_enc(struct padata_priv *padata)
  {
  	struct pcrypt_request *preq = pcrypt_padata_request(padata);
  	struct aead_request *req = pcrypt_request_ctx(preq);
  
  	padata->info = crypto_aead_encrypt(req);

  	if (padata->info == -EINPROGRESS)

  		return;
  
  	padata_do_serial(padata);
  }
  
  static int pcrypt_aead_encrypt(struct aead_request *req)
  {
  	int err;
  	struct pcrypt_request *preq = aead_request_ctx(req);
  	struct aead_request *creq = pcrypt_request_ctx(preq);
  	struct padata_priv *padata = pcrypt_request_padata(preq);
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
  	u32 flags = aead_request_flags(req);
  
  	memset(padata, 0, sizeof(struct padata_priv));
  
  	padata->parallel = pcrypt_aead_enc;
  	padata->serial = pcrypt_aead_serial;
  
  	aead_request_set_tfm(creq, ctx->child);
  	aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
  				  pcrypt_aead_done, req);
  	aead_request_set_crypt(creq, req->src, req->dst,
  			       req->cryptlen, req->iv);
  	aead_request_set_assoc(creq, req->assoc, req->assoclen);

  	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pencrypt);

  	if (!err)
  		return -EINPROGRESS;

  
  	return err;
  }
  
  static void pcrypt_aead_dec(struct padata_priv *padata)
  {
  	struct pcrypt_request *preq = pcrypt_padata_request(padata);
  	struct aead_request *req = pcrypt_request_ctx(preq);
  
  	padata->info = crypto_aead_decrypt(req);

  	if (padata->info == -EINPROGRESS)

  		return;
  
  	padata_do_serial(padata);
  }
  
  static int pcrypt_aead_decrypt(struct aead_request *req)
  {
  	int err;
  	struct pcrypt_request *preq = aead_request_ctx(req);
  	struct aead_request *creq = pcrypt_request_ctx(preq);
  	struct padata_priv *padata = pcrypt_request_padata(preq);
  	struct crypto_aead *aead = crypto_aead_reqtfm(req);
  	struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
  	u32 flags = aead_request_flags(req);
  
  	memset(padata, 0, sizeof(struct padata_priv));
  
  	padata->parallel = pcrypt_aead_dec;
  	padata->serial = pcrypt_aead_serial;
  
  	aead_request_set_tfm(creq, ctx->child);
  	aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
  				  pcrypt_aead_done, req);
  	aead_request_set_crypt(creq, req->src, req->dst,
  			       req->cryptlen, req->iv);
  	aead_request_set_assoc(creq, req->assoc, req->assoclen);

  	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pdecrypt);

  	if (!err)
  		return -EINPROGRESS;

  
  	return err;
  }
  
  static void pcrypt_aead_givenc(struct padata_priv *padata)
  {
  	struct pcrypt_request *preq = pcrypt_padata_request(padata);
  	struct aead_givcrypt_request *req = pcrypt_request_ctx(preq);
  
  	padata->info = crypto_aead_givencrypt(req);

  	if (padata->info == -EINPROGRESS)

  		return;
  
  	padata_do_serial(padata);
  }
  
  static int pcrypt_aead_givencrypt(struct aead_givcrypt_request *req)
  {
  	int err;
  	struct aead_request *areq = &req->areq;
  	struct pcrypt_request *preq = aead_request_ctx(areq);
  	struct aead_givcrypt_request *creq = pcrypt_request_ctx(preq);
  	struct padata_priv *padata = pcrypt_request_padata(preq);
  	struct crypto_aead *aead = aead_givcrypt_reqtfm(req);
  	struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
  	u32 flags = aead_request_flags(areq);
  
  	memset(padata, 0, sizeof(struct padata_priv));
  
  	padata->parallel = pcrypt_aead_givenc;
  	padata->serial = pcrypt_aead_giv_serial;
  
  	aead_givcrypt_set_tfm(creq, ctx->child);
  	aead_givcrypt_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
  				   pcrypt_aead_done, areq);
  	aead_givcrypt_set_crypt(creq, areq->src, areq->dst,
  				areq->cryptlen, areq->iv);
  	aead_givcrypt_set_assoc(creq, areq->assoc, areq->assoclen);
  	aead_givcrypt_set_giv(creq, req->giv, req->seq);

  	err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pencrypt);

  	if (!err)
  		return -EINPROGRESS;

  
  	return err;
  }
  
  static int pcrypt_aead_init_tfm(struct crypto_tfm *tfm)
  {
  	int cpu, cpu_index;
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct pcrypt_instance_ctx *ictx = crypto_instance_ctx(inst);
  	struct pcrypt_aead_ctx *ctx = crypto_tfm_ctx(tfm);
  	struct crypto_aead *cipher;
  
  	ictx->tfm_count++;
  
  	cpu_index = ictx->tfm_count % cpumask_weight(cpu_active_mask);
  
  	ctx->cb_cpu = cpumask_first(cpu_active_mask);
  	for (cpu = 0; cpu < cpu_index; cpu++)
  		ctx->cb_cpu = cpumask_next(ctx->cb_cpu, cpu_active_mask);
  
  	cipher = crypto_spawn_aead(crypto_instance_ctx(inst));
  
  	if (IS_ERR(cipher))
  		return PTR_ERR(cipher);
  
  	ctx->child = cipher;
  	tfm->crt_aead.reqsize = sizeof(struct pcrypt_request)
  		+ sizeof(struct aead_givcrypt_request)
  		+ crypto_aead_reqsize(cipher);
  
  	return 0;
  }
  
  static void pcrypt_aead_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct pcrypt_aead_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_aead(ctx->child);
  }
  
  static struct crypto_instance *pcrypt_alloc_instance(struct crypto_alg *alg)
  {
  	struct crypto_instance *inst;
  	struct pcrypt_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,
  		     "pcrypt(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
  		goto out_free_inst;
  
  	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  
  	ctx = crypto_instance_ctx(inst);
  	err = crypto_init_spawn(&ctx->spawn, alg, inst,
  				CRYPTO_ALG_TYPE_MASK);
  	if (err)
  		goto out_free_inst;
  
  	inst->alg.cra_priority = alg->cra_priority + 100;
  	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 *pcrypt_alloc_aead(struct rtattr **tb,
  						 u32 type, u32 mask)

  {
  	struct crypto_instance *inst;
  	struct crypto_alg *alg;

  	alg = crypto_get_attr_alg(tb, type, (mask & CRYPTO_ALG_TYPE_MASK));

  	if (IS_ERR(alg))
  		return ERR_CAST(alg);
  
  	inst = pcrypt_alloc_instance(alg);
  	if (IS_ERR(inst))
  		goto out_put_alg;
  
  	inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
  	inst->alg.cra_type = &crypto_aead_type;
  
  	inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
  	inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
  	inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
  
  	inst->alg.cra_ctxsize = sizeof(struct pcrypt_aead_ctx);
  
  	inst->alg.cra_init = pcrypt_aead_init_tfm;
  	inst->alg.cra_exit = pcrypt_aead_exit_tfm;
  
  	inst->alg.cra_aead.setkey = pcrypt_aead_setkey;
  	inst->alg.cra_aead.setauthsize = pcrypt_aead_setauthsize;
  	inst->alg.cra_aead.encrypt = pcrypt_aead_encrypt;
  	inst->alg.cra_aead.decrypt = pcrypt_aead_decrypt;
  	inst->alg.cra_aead.givencrypt = pcrypt_aead_givencrypt;
  
  out_put_alg:
  	crypto_mod_put(alg);
  	return inst;
  }
  
  static struct crypto_instance *pcrypt_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_AEAD:

  		return pcrypt_alloc_aead(tb, algt->type, algt->mask);

  	}
  
  	return ERR_PTR(-EINVAL);
  }
  
  static void pcrypt_free(struct crypto_instance *inst)
  {
  	struct pcrypt_instance_ctx *ctx = crypto_instance_ctx(inst);
  
  	crypto_drop_spawn(&ctx->spawn);
  	kfree(inst);
  }

  static int pcrypt_cpumask_change_notify(struct notifier_block *self,
  					unsigned long val, void *data)
  {

  	struct padata_pcrypt *pcrypt;

  	struct pcrypt_cpumask *new_mask, *old_mask;

  	struct padata_cpumask *cpumask = (struct padata_cpumask *)data;

  
  	if (!(val & PADATA_CPU_SERIAL))
  		return 0;

  	pcrypt = container_of(self, struct padata_pcrypt, nblock);

  	new_mask = kmalloc(sizeof(*new_mask), GFP_KERNEL);
  	if (!new_mask)
  		return -ENOMEM;
  	if (!alloc_cpumask_var(&new_mask->mask, GFP_KERNEL)) {
  		kfree(new_mask);
  		return -ENOMEM;
  	}
  
  	old_mask = pcrypt->cb_cpumask;

  	cpumask_copy(new_mask->mask, cpumask->cbcpu);

  	rcu_assign_pointer(pcrypt->cb_cpumask, new_mask);
  	synchronize_rcu_bh();
  
  	free_cpumask_var(old_mask->mask);
  	kfree(old_mask);
  	return 0;
  }

  static int pcrypt_sysfs_add(struct padata_instance *pinst, const char *name)
  {
  	int ret;
  
  	pinst->kobj.kset = pcrypt_kset;
  	ret = kobject_add(&pinst->kobj, NULL, name);
  	if (!ret)
  		kobject_uevent(&pinst->kobj, KOBJ_ADD);
  
  	return ret;
  }

  static int pcrypt_init_padata(struct padata_pcrypt *pcrypt,
  			      const char *name)

  {
  	int ret = -ENOMEM;
  	struct pcrypt_cpumask *mask;

  	get_online_cpus();

  	pcrypt->wq = alloc_workqueue(name,
  				     WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE, 1);

  	if (!pcrypt->wq)
  		goto err;

  	pcrypt->pinst = padata_alloc_possible(pcrypt->wq);

  	if (!pcrypt->pinst)
  		goto err_destroy_workqueue;
  
  	mask = kmalloc(sizeof(*mask), GFP_KERNEL);
  	if (!mask)
  		goto err_free_padata;
  	if (!alloc_cpumask_var(&mask->mask, GFP_KERNEL)) {
  		kfree(mask);
  		goto err_free_padata;
  	}

  	cpumask_and(mask->mask, cpu_possible_mask, cpu_active_mask);

  	rcu_assign_pointer(pcrypt->cb_cpumask, mask);
  
  	pcrypt->nblock.notifier_call = pcrypt_cpumask_change_notify;
  	ret = padata_register_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);
  	if (ret)
  		goto err_free_cpumask;

  	ret = pcrypt_sysfs_add(pcrypt->pinst, name);
  	if (ret)
  		goto err_unregister_notifier;

  	put_online_cpus();

  	return ret;

  err_unregister_notifier:
  	padata_unregister_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);

  err_free_cpumask:
  	free_cpumask_var(mask->mask);
  	kfree(mask);
  err_free_padata:
  	padata_free(pcrypt->pinst);
  err_destroy_workqueue:
  	destroy_workqueue(pcrypt->wq);
  err:

  	put_online_cpus();

  	return ret;
  }

  static void pcrypt_fini_padata(struct padata_pcrypt *pcrypt)

  {
  	free_cpumask_var(pcrypt->cb_cpumask->mask);
  	kfree(pcrypt->cb_cpumask);
  
  	padata_stop(pcrypt->pinst);
  	padata_unregister_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);
  	destroy_workqueue(pcrypt->wq);
  	padata_free(pcrypt->pinst);
  }

  static struct crypto_template pcrypt_tmpl = {
  	.name = "pcrypt",
  	.alloc = pcrypt_alloc,
  	.free = pcrypt_free,
  	.module = THIS_MODULE,
  };
  
  static int __init pcrypt_init(void)
  {

  	int err = -ENOMEM;
  
  	pcrypt_kset = kset_create_and_add("pcrypt", NULL, kernel_kobj);
  	if (!pcrypt_kset)
  		goto err;

  	err = pcrypt_init_padata(&pencrypt, "pencrypt");

  	if (err)

  		goto err_unreg_kset;

  	err = pcrypt_init_padata(&pdecrypt, "pdecrypt");

  	if (err)

  		goto err_deinit_pencrypt;

  	padata_start(pencrypt.pinst);
  	padata_start(pdecrypt.pinst);

  	return crypto_register_template(&pcrypt_tmpl);

  err_deinit_pencrypt:

  	pcrypt_fini_padata(&pencrypt);

  err_unreg_kset:
  	kset_unregister(pcrypt_kset);

  err:

  	return err;

  }
  
  static void __exit pcrypt_exit(void)
  {

  	pcrypt_fini_padata(&pencrypt);
  	pcrypt_fini_padata(&pdecrypt);

  	kset_unregister(pcrypt_kset);

  	crypto_unregister_template(&pcrypt_tmpl);
  }
  
  module_init(pcrypt_init);
  module_exit(pcrypt_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
  MODULE_DESCRIPTION("Parallel crypto wrapper");