hostap_crypt.c

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/*
 * Host AP crypto routines
 *
 * Copyright (c) 2002-2003, Jouni Malinen <jkmaline@cc.hut.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. See README and COPYING for
 * more details.
 */

#ifdef HOSTAP_CRYPT_MODULE
#ifndef EXPORT_SYMTAB
#define EXPORT_SYMTAB
#endif

#include <linux/config.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <asm/string.h>
#include <asm/errno.h>

#include "hostap_crypt.h"
#include "hostap_compat.h"

MODULE_AUTHOR("Jouni Malinen");
MODULE_DESCRIPTION("Host AP crypto");
MODULE_LICENSE("GPL");
#endif /* HOSTAP_CRYPT_MODULE */


struct hostap_crypto_alg {
        struct list_head list;
        struct hostap_crypto_ops *ops;
};


struct hostap_crypto {
        struct list_head algs;
        spinlock_t lock;
};

static struct hostap_crypto *hcrypt;


int hostap_register_crypto_ops(struct hostap_crypto_ops *ops)
{
        unsigned long flags;
        struct hostap_crypto_alg *alg;

        if (hcrypt == NULL)
                return -1;

        alg = (struct hostap_crypto_alg *) kmalloc(sizeof(*alg), GFP_KERNEL);
        if (alg == NULL)
                return -ENOMEM;

        memset(alg, 0, sizeof(*alg));
        alg->ops = ops;

        spin_lock_irqsave(&hcrypt->lock, flags);
        list_add(&alg->list, &hcrypt->algs);
        spin_unlock_irqrestore(&hcrypt->lock, flags);

        printk(KERN_DEBUG "hostap_crypt: registered algorithm '%s'\n",
               ops->name);

        return 0;
}


int hostap_unregister_crypto_ops(struct hostap_crypto_ops *ops)
{
        unsigned long flags;
        struct list_head *ptr;
        struct hostap_crypto_alg *del_alg = NULL;

        if (hcrypt == NULL)
                return -1;

        spin_lock_irqsave(&hcrypt->lock, flags);
        for (ptr = hcrypt->algs.next; ptr != &hcrypt->algs; ptr = ptr->next) {
                struct hostap_crypto_alg *alg =
                        (struct hostap_crypto_alg *) ptr;
                if (alg->ops == ops) {
                        list_del(&alg->list);
                        del_alg = alg;
                        break;
                }
        }
        spin_unlock_irqrestore(&hcrypt->lock, flags);

        if (del_alg) {
                printk(KERN_DEBUG "hostap_crypt: unregistered algorithm "
                       "'%s'\n", ops->name);
                kfree(del_alg);
        }

        return del_alg ? 0 : -1;
}


struct hostap_crypto_ops * hostap_get_crypto_ops(const char *name)
{
        unsigned long flags;
        struct list_head *ptr;
        struct hostap_crypto_alg *found_alg = NULL;

        if (hcrypt == NULL)
                return NULL;

        spin_lock_irqsave(&hcrypt->lock, flags);
        for (ptr = hcrypt->algs.next; ptr != &hcrypt->algs; ptr = ptr->next) {
                struct hostap_crypto_alg *alg =
                        (struct hostap_crypto_alg *) ptr;
                if (strcmp(alg->ops->name, name) == 0) {
                        found_alg = alg;
                        break;
                }
        }
        spin_unlock_irqrestore(&hcrypt->lock, flags);

        if (found_alg)
                return found_alg->ops;
        else
                return NULL;
}


static void * hostap_crypt_null_init(void) { return (void *) 1; }
static void hostap_crypt_null_deinit(void *priv) {}

static struct hostap_crypto_ops hostap_crypt_null = {
        .name                   = "NULL",
        .init                   = hostap_crypt_null_init,
        .deinit                 = hostap_crypt_null_deinit,
        .encrypt                = NULL,
        .decrypt                = NULL,
        .set_key                = NULL,
        .get_key                = NULL,
        .set_key_idx            = NULL,
        .get_key_idx            = NULL,
        .extra_prefix_len       = 0,
        .extra_postfix_len      = 0
};


static int __init hostap_crypto_init(void)
{
        hcrypt = (struct hostap_crypto *) kmalloc(sizeof(*hcrypt), GFP_KERNEL);
        if (hcrypt == NULL)
                return -ENOMEM;

        memset(hcrypt, 0, sizeof(*hcrypt));
        INIT_LIST_HEAD(&hcrypt->algs);
        spin_lock_init(&hcrypt->lock);

        (void) hostap_register_crypto_ops(&hostap_crypt_null);

        return 0;
}


static void __exit hostap_crypto_deinit(void)
{
        struct list_head *ptr, *n;

        if (hcrypt == NULL)
                return;

        for (ptr = hcrypt->algs.next, n = ptr->next; ptr != &hcrypt->algs;
             ptr = n, n = ptr->next) {
                struct hostap_crypto_alg *alg =
                        (struct hostap_crypto_alg *) ptr;
                list_del(ptr);
                printk(KERN_DEBUG "hostap_crypt: unregistered algorithm "
                       "'%s' (deinit)\n", alg->ops->name);
                kfree(alg);
        }

        kfree(hcrypt);
}


EXPORT_SYMBOL(hostap_register_crypto_ops);
EXPORT_SYMBOL(hostap_unregister_crypto_ops);
EXPORT_SYMBOL(hostap_get_crypto_ops);

#ifdef HOSTAP_CRYPT_MODULE
module_init(hostap_crypto_init);
module_exit(hostap_crypto_deinit);
#endif /* HOSTAP_CRYPT_MODULE */

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