[CRYPTO] api: Add template registration

A crypto_template generates a crypto_alg object when given a set of
parameters.  this patch adds the basic data structure fo templates
and code to handle their registration/deregistration.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 182 insertions, 22 deletions

diff --git a/crypto/algapi.c b/crypto/algapi.c
index a65c6ccfbe17..232b37d81613 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -13,11 +13,14 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/string.h>
 
 #include "internal.h"
 
+static LIST_HEAD(crypto_template_list);
+
 static inline int crypto_set_driver_name(struct crypto_alg *alg)
 {
         static const char suffix[] = "-generic";
@@ -35,11 +38,8 @@ static inline int crypto_set_driver_name(struct crypto_alg *alg)
         return 0;
 }
 
-int crypto_register_alg(struct crypto_alg *alg)
+static int crypto_check_alg(struct crypto_alg *alg)
 {
-        int ret;
-        struct crypto_alg *q;
-
         if (alg->cra_alignmask & (alg->cra_alignmask + 1))
                 return -EINVAL;
 
@@ -51,42 +51,52 @@ int crypto_register_alg(struct crypto_alg *alg)
 
         if (alg->cra_priority < 0)
                 return -EINVAL;
-        
-        ret = crypto_set_driver_name(alg);
-        if (unlikely(ret))
-                return ret;
 
-        down_write(&crypto_alg_sem);
-        
+        return crypto_set_driver_name(alg);
+}
+
+static int __crypto_register_alg(struct crypto_alg *alg)
+{
+        struct crypto_alg *q;
+        int ret = -EEXIST;
+
         list_for_each_entry(q, &crypto_alg_list, cra_list) {
-                if (q == alg) {
-                        ret = -EEXIST;
+                if (q == alg)
                         goto out;
-                }
         }
         
         list_add(&alg->cra_list, &crypto_alg_list);
         atomic_set(&alg->cra_refcnt, 1);
+        ret = 0;
 out:    
-        up_write(&crypto_alg_sem);
         return ret;
 }
+
+int crypto_register_alg(struct crypto_alg *alg)
+{
+        int err;
+
+        err = crypto_check_alg(alg);
+        if (err)
+                return err;
+
+        down_write(&crypto_alg_sem);
+        err = __crypto_register_alg(alg);
+        up_write(&crypto_alg_sem);
+
+        return err;
+}
 EXPORT_SYMBOL_GPL(crypto_register_alg);
 
 int crypto_unregister_alg(struct crypto_alg *alg)
 {
         int ret = -ENOENT;
-        struct crypto_alg *q;
         
         down_write(&crypto_alg_sem);
-        list_for_each_entry(q, &crypto_alg_list, cra_list) {
-                if (alg == q) {
-                        list_del(&alg->cra_list);
-                        ret = 0;
-                        goto out;
-                }
+        if (likely(!list_empty(&alg->cra_list))) {
+                list_del_init(&alg->cra_list);
+                ret = 0;
         }
-out:    
         up_write(&crypto_alg_sem);
 
         if (ret)
@@ -100,6 +110,108 @@ out:
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
 
+int crypto_register_template(struct crypto_template *tmpl)
+{
+        struct crypto_template *q;
+        int err = -EEXIST;
+
+        down_write(&crypto_alg_sem);
+
+        list_for_each_entry(q, &crypto_template_list, list) {
+                if (q == tmpl)
+                        goto out;
+        }
+
+        list_add(&tmpl->list, &crypto_template_list);
+        err = 0;
+out:
+        up_write(&crypto_alg_sem);
+        return err;
+}
+EXPORT_SYMBOL_GPL(crypto_register_template);
+
+void crypto_unregister_template(struct crypto_template *tmpl)
+{
+        struct crypto_instance *inst;
+        struct hlist_node *p, *n;
+        struct hlist_head *list;
+
+        down_write(&crypto_alg_sem);
+
+        BUG_ON(list_empty(&tmpl->list));
+        list_del_init(&tmpl->list);
+
+        list = &tmpl->instances;
+        hlist_for_each_entry(inst, p, list, list) {
+                BUG_ON(list_empty(&inst->alg.cra_list));
+                list_del_init(&inst->alg.cra_list);
+        }
+
+        up_write(&crypto_alg_sem);
+
+        hlist_for_each_entry_safe(inst, p, n, list, list) {
+                BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
+                tmpl->free(inst);
+        }
+}
+EXPORT_SYMBOL_GPL(crypto_unregister_template);
+
+static struct crypto_template *__crypto_lookup_template(const char *name)
+{
+        struct crypto_template *q, *tmpl = NULL;
+
+        down_read(&crypto_alg_sem);
+        list_for_each_entry(q, &crypto_template_list, list) {
+                if (strcmp(q->name, name))
+                        continue;
+                if (unlikely(!crypto_tmpl_get(q)))
+                        continue;
+
+                tmpl = q;
+                break;
+        }
+        up_read(&crypto_alg_sem);
+
+        return tmpl;
+}
+
+struct crypto_template *crypto_lookup_template(const char *name)
+{
+        return try_then_request_module(__crypto_lookup_template(name), name);
+}
+EXPORT_SYMBOL_GPL(crypto_lookup_template);
+
+int crypto_register_instance(struct crypto_template *tmpl,
+                             struct crypto_instance *inst)
+{
+        int err = -EINVAL;
+
+        if (inst->alg.cra_destroy)
+                goto err;
+
+        err = crypto_check_alg(&inst->alg);
+        if (err)
+                goto err;
+
+        inst->alg.cra_module = tmpl->module;
+
+        down_write(&crypto_alg_sem);
+
+        err = __crypto_register_alg(&inst->alg);
+        if (err)
+                goto unlock;
+
+        hlist_add_head(&inst->list, &tmpl->instances);
+        inst->tmpl = tmpl;
+
+unlock:
+        up_write(&crypto_alg_sem);
+
+err:
+        return err;
+}
+EXPORT_SYMBOL_GPL(crypto_register_instance);
+
 static int __init crypto_algapi_init(void)
 {
         crypto_init_proc();
diff --git a/crypto/internal.h b/crypto/internal.h
index 26f47d331551..c3ab4a950f30 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -19,11 +19,15 @@
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/list.h>
+#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 #include <asm/kmap_types.h>
 
+struct crypto_instance;
+struct crypto_template;
+
 extern struct list_head crypto_alg_list;
 extern struct rw_semaphore crypto_alg_sem;
 
@@ -112,5 +116,18 @@ void crypto_exit_digest_ops(struct crypto_tfm *tfm);
 void crypto_exit_cipher_ops(struct crypto_tfm *tfm);
 void crypto_exit_compress_ops(struct crypto_tfm *tfm);
 
+int crypto_register_instance(struct crypto_template *tmpl,
+                             struct crypto_instance *inst);
+
+static inline int crypto_tmpl_get(struct crypto_template *tmpl)
+{
+        return try_module_get(tmpl->module);
+}
+
+static inline void crypto_tmpl_put(struct crypto_template *tmpl)
+{
+        module_put(tmpl->module);
+}
+
 #endif  /* _CRYPTO_INTERNAL_H */
 
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index ed68d494b364..ffec530d52fb 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -14,5 +14,36 @@
 
 #include <linux/crypto.h>
 
+struct module;
+
+struct crypto_instance {
+        struct crypto_alg alg;
+
+        struct crypto_template *tmpl;
+        struct hlist_node list;
+
+        void *__ctx[] CRYPTO_MINALIGN_ATTR;
+};
+
+struct crypto_template {
+        struct list_head list;
+        struct hlist_head instances;
+        struct module *module;
+
+        struct crypto_instance *(*alloc)(void *param, unsigned int len);
+        void (*free)(struct crypto_instance *inst);
+
+        char name[CRYPTO_MAX_ALG_NAME];
+};
+
+int crypto_register_template(struct crypto_template *tmpl);
+void crypto_unregister_template(struct crypto_template *tmpl);
+struct crypto_template *crypto_lookup_template(const char *name);
+
+static inline void *crypto_instance_ctx(struct crypto_instance *inst)
+{
+        return inst->__ctx;
+}
+
 #endif  /* _CRYPTO_ALGAPI_H */