[CRYPTO] cryptd: Add software async crypto daemon
This patch adds the cryptd module which is a template that takes a
synchronous software crypto algorithm and converts it to an asynchronous
one by executing it in a kernel thread.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
new file mode 100644
index 0000000..3ff4e1f
--- /dev/null
+++ b/crypto/cryptd.c
@@ -0,0 +1,375 @@
+/*
+ * 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(crypto_ablkcipher_alg(tfm), 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(__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;
+
+ inst->alg.cra_ablkcipher.queue = &state->queue;
+
+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_create(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;
+
+ 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");