rtllib_crypt.c

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/*
 * Host AP crypto routines
 *
 * Copyright (c) 2002-2003, Jouni Malinen <[email protected]>
 * Portions Copyright (C) 2004, Intel Corporation <[email protected]>
 *
 * 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.
 *
 */

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

#include "rtllib.h"

struct rtllib_crypto_alg {
    struct list_head list;
    struct lib80211_crypto_ops *ops;
};


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

static struct rtllib_crypto *hcrypt;

void rtllib_crypt_deinit_entries(struct lib80211_crypt_info *info,
                       int force)
{
    struct list_head *ptr, *n;
    struct lib80211_crypt_data *entry;

    for (ptr = info->crypt_deinit_list.next, n = ptr->next;
         ptr != &info->crypt_deinit_list; ptr = n, n = ptr->next) {
        entry = list_entry(ptr, struct lib80211_crypt_data, list);

        if (atomic_read(&entry->refcnt) != 0 && !force)
            continue;

        list_del(ptr);

        if (entry->ops)
            entry->ops->deinit(entry->priv);
        kfree(entry);
    }
}
EXPORT_SYMBOL(rtllib_crypt_deinit_entries);

void rtllib_crypt_deinit_handler(unsigned long data)
{
    struct lib80211_crypt_info *info = (struct lib80211_crypt_info *)data;
    unsigned long flags;

    spin_lock_irqsave(info->lock, flags);
    rtllib_crypt_deinit_entries(info, 0);
    if (!list_empty(&info->crypt_deinit_list)) {
        printk(KERN_DEBUG "%s: entries remaining in delayed crypt "
               "deletion list\n", info->name);
        info->crypt_deinit_timer.expires = jiffies + HZ;
        add_timer(&info->crypt_deinit_timer);
    }
    spin_unlock_irqrestore(info->lock, flags);

}
EXPORT_SYMBOL(rtllib_crypt_deinit_handler);

void rtllib_crypt_delayed_deinit(struct lib80211_crypt_info *info,
                 struct lib80211_crypt_data **crypt)
{
    struct lib80211_crypt_data *tmp;
    unsigned long flags;

    if (*crypt == NULL)
        return;

    tmp = *crypt;
    *crypt = NULL;

    /* must not run ops->deinit() while there may be pending encrypt or
     * decrypt operations. Use a list of delayed deinits to avoid needing
     * locking. */

    spin_lock_irqsave(info->lock, flags);
    list_add(&tmp->list, &info->crypt_deinit_list);
    if (!timer_pending(&info->crypt_deinit_timer)) {
        info->crypt_deinit_timer.expires = jiffies + HZ;
        add_timer(&info->crypt_deinit_timer);
    }
    spin_unlock_irqrestore(info->lock, flags);
}
EXPORT_SYMBOL(rtllib_crypt_delayed_deinit);

int rtllib_register_crypto_ops(struct lib80211_crypto_ops *ops)
{
    unsigned long flags;
    struct rtllib_crypto_alg *alg;

    if (hcrypt == NULL)
        return -1;

    alg = kzalloc(sizeof(*alg), GFP_KERNEL);
    if (alg == NULL)
        return -ENOMEM;

    alg->ops = ops;

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

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

    return 0;
}
EXPORT_SYMBOL(rtllib_register_crypto_ops);

int rtllib_unregister_crypto_ops(struct lib80211_crypto_ops *ops)
{
    unsigned long flags;
    struct list_head *ptr;
    struct rtllib_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 rtllib_crypto_alg *alg =
            (struct rtllib_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 "rtllib_crypt: unregistered algorithm "
               "'%s'\n", ops->name);
        kfree(del_alg);
    }

    return del_alg ? 0 : -1;
}
EXPORT_SYMBOL(rtllib_unregister_crypto_ops);


struct lib80211_crypto_ops *rtllib_get_crypto_ops(const char *name)
{
    unsigned long flags;
    struct list_head *ptr;
    struct rtllib_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 rtllib_crypto_alg *alg =
            (struct rtllib_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;
}
EXPORT_SYMBOL(rtllib_get_crypto_ops);


static void * rtllib_crypt_null_init(int keyidx) { return (void *) 1; }
static void rtllib_crypt_null_deinit(void *priv) {}

static struct lib80211_crypto_ops rtllib_crypt_null = {
    .name           = "NULL",
    .init           = rtllib_crypt_null_init,
    .deinit         = rtllib_crypt_null_deinit,
    .encrypt_mpdu       = NULL,
    .decrypt_mpdu       = NULL,
    .encrypt_msdu       = NULL,
    .decrypt_msdu       = NULL,
    .set_key        = NULL,
    .get_key        = NULL,
    .extra_mpdu_prefix_len  = 0,
    .extra_mpdu_postfix_len = 0,
    .extra_msdu_prefix_len  = 0,
    .extra_msdu_postfix_len = 0,
    .owner          = THIS_MODULE,
};


int __init rtllib_crypto_init(void)
{
    int ret = -ENOMEM;

    hcrypt = kzalloc(sizeof(*hcrypt), GFP_KERNEL);
    if (!hcrypt)
        goto out;

    INIT_LIST_HEAD(&hcrypt->algs);
    spin_lock_init(&hcrypt->lock);

    ret = lib80211_register_crypto_ops(&rtllib_crypt_null);
    if (ret < 0) {
        kfree(hcrypt);
        hcrypt = NULL;
    }
out:
    return ret;
}


void __exit rtllib_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 rtllib_crypto_alg *alg =
            (struct rtllib_crypto_alg *) ptr;
        list_del(ptr);
        printk(KERN_DEBUG "rtllib_crypt: unregistered algorithm "
               "'%s' (deinit)\n", alg->ops->name);
        kfree(alg);
    }

    kfree(hcrypt);
}

module_init(rtllib_crypto_init);
module_exit(rtllib_crypto_deinit);

MODULE_LICENSE("GPL");