[CRYPTO] api: Split out low-level API

The crypto API is made up of the part facing users such as IPsec and the
low-level part which is used by cryptographic entities such as algorithms.
This patch splits out the latter so that the two APIs are more clearly
delineated.  As a bonus the low-level API can now be modularised if all
algorithms are built as modules.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 118 insertions, 0 deletions

diff --git a/crypto/algapi.c b/crypto/algapi.c
new file mode 100644
index 000000000000..a65c6ccfbe17
--- /dev/null
+++ b/crypto/algapi.c
@@ -0,0 +1,118 @@
+/*
+ * Cryptographic API for algorithms (i.e., low-level API).
+ *
+ * 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 <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include "internal.h"
+
+static inline int crypto_set_driver_name(struct crypto_alg *alg)
+{
+        static const char suffix[] = "-generic";
+        char *driver_name = alg->cra_driver_name;
+        int len;
+
+        if (*driver_name)
+                return 0;
+
+        len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
+        if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
+                return -ENAMETOOLONG;
+
+        memcpy(driver_name + len, suffix, sizeof(suffix));
+        return 0;
+}
+
+int crypto_register_alg(struct crypto_alg *alg)
+{
+        int ret;
+        struct crypto_alg *q;
+
+        if (alg->cra_alignmask & (alg->cra_alignmask + 1))
+                return -EINVAL;
+
+        if (alg->cra_alignmask & alg->cra_blocksize)
+                return -EINVAL;
+
+        if (alg->cra_blocksize > PAGE_SIZE / 8)
+                return -EINVAL;
+
+        if (alg->cra_priority < 0)
+                return -EINVAL;
+        
+        ret = crypto_set_driver_name(alg);
+        if (unlikely(ret))
+                return ret;
+
+        down_write(&crypto_alg_sem);
+        
+        list_for_each_entry(q, &crypto_alg_list, cra_list) {
+                if (q == alg) {
+                        ret = -EEXIST;
+                        goto out;
+                }
+        }
+        
+        list_add(&alg->cra_list, &crypto_alg_list);
+        atomic_set(&alg->cra_refcnt, 1);
+out:    
+        up_write(&crypto_alg_sem);
+        return ret;
+}
+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;
+                }
+        }
+out:    
+        up_write(&crypto_alg_sem);
+
+        if (ret)
+                return ret;
+
+        BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
+        if (alg->cra_destroy)
+                alg->cra_destroy(alg);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_unregister_alg);
+
+static int __init crypto_algapi_init(void)
+{
+        crypto_init_proc();
+        return 0;
+}
+
+static void __exit crypto_algapi_exit(void)
+{
+        crypto_exit_proc();
+}
+
+module_init(crypto_algapi_init);
+module_exit(crypto_algapi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Cryptographic algorithms API");