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/*

 * 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 (IS_ERR(inst))

                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 | CRYPTO_ALG_ASYNC);

        if (IS_ERR(alg))

                return ERR_PTR(PTR_ERR(alg));

        inst = cryptd_alloc_instance(alg, state);

        if (IS_ERR(inst))

                goto out_put_alg;

        inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | 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_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_PTR(PTR_ERR(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");