ieee80211_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/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <asm/string.h>
#include <asm/errno.h>

#include "ieee80211.h"

MODULE_AUTHOR("Jouni Malinen");
MODULE_DESCRIPTION("HostAP crypto");
MODULE_LICENSE("GPL");

struct ieee80211_crypto_alg {
    struct list_head list;
    struct ieee80211_crypto_ops *ops;
};


struct ieee80211_crypto {
    struct list_head algs;
    spinlock_t lock;
};

static struct ieee80211_crypto *hcrypt;

void ieee80211_crypt_deinit_entries(struct ieee80211_device *ieee,
                       int force)
{
    struct list_head *ptr, *n;
    struct ieee80211_crypt_data *entry;

    for (ptr = ieee->crypt_deinit_list.next, n = ptr->next;
         ptr != &ieee->crypt_deinit_list; ptr = n, n = ptr->next) {
        entry = list_entry(ptr, struct ieee80211_crypt_data, list);

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

        list_del(ptr);

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

void ieee80211_crypt_deinit_handler(unsigned long data)
{
    struct ieee80211_device *ieee = (struct ieee80211_device *)data;
    unsigned long flags;

    spin_lock_irqsave(&ieee->lock, flags);
    ieee80211_crypt_deinit_entries(ieee, 0);
    if (!list_empty(&ieee->crypt_deinit_list)) {
        printk(KERN_DEBUG "%s: entries remaining in delayed crypt "
               "deletion list\n", ieee->dev->name);
        ieee->crypt_deinit_timer.expires = jiffies + HZ;
        add_timer(&ieee->crypt_deinit_timer);
    }
    spin_unlock_irqrestore(&ieee->lock, flags);

}

void ieee80211_crypt_delayed_deinit(struct ieee80211_device *ieee,
                    struct ieee80211_crypt_data **crypt)
{
    struct ieee80211_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(&ieee->lock, flags);
    list_add(&tmp->list, &ieee->crypt_deinit_list);
    if (!timer_pending(&ieee->crypt_deinit_timer)) {
        ieee->crypt_deinit_timer.expires = jiffies + HZ;
        add_timer(&ieee->crypt_deinit_timer);
    }
    spin_unlock_irqrestore(&ieee->lock, flags);
}

int ieee80211_register_crypto_ops(struct ieee80211_crypto_ops *ops)
{
    unsigned long flags;
    struct ieee80211_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 "ieee80211_crypt: registered algorithm '%s'\n",
           ops->name);

    return 0;
}

int ieee80211_unregister_crypto_ops(struct ieee80211_crypto_ops *ops)
{
    unsigned long flags;
    struct list_head *ptr;
    struct ieee80211_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 ieee80211_crypto_alg *alg =
            (struct ieee80211_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 "ieee80211_crypt: unregistered algorithm "
               "'%s'\n", ops->name);
        kfree(del_alg);
    }

    return del_alg ? 0 : -1;
}


struct ieee80211_crypto_ops * ieee80211_get_crypto_ops(const char *name)
{
    unsigned long flags;
    struct list_head *ptr;
    struct ieee80211_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 ieee80211_crypto_alg *alg =
            (struct ieee80211_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 * ieee80211_crypt_null_init(int keyidx) { return (void *) 1; }
static void ieee80211_crypt_null_deinit(void *priv) {}

static struct ieee80211_crypto_ops ieee80211_crypt_null = {
    .name           = "NULL",
    .init           = ieee80211_crypt_null_init,
    .deinit         = ieee80211_crypt_null_deinit,
    .encrypt_mpdu       = NULL,
    .decrypt_mpdu       = NULL,
    .encrypt_msdu       = NULL,
    .decrypt_msdu       = NULL,
    .set_key        = NULL,
    .get_key        = NULL,
    .extra_prefix_len   = 0,
    .extra_postfix_len  = 0,
    .owner          = THIS_MODULE,
};

int __init ieee80211_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 = ieee80211_register_crypto_ops(&ieee80211_crypt_null);
    if (ret < 0) {
        kfree(hcrypt);
        hcrypt = NULL;
    }
out:
    return ret;
}

void __exit ieee80211_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 ieee80211_crypto_alg *alg =
            (struct ieee80211_crypto_alg *) ptr;
        list_del(ptr);
        printk(KERN_DEBUG "ieee80211_crypt: unregistered algorithm "
               "'%s' (deinit)\n", alg->ops->name);
        kfree(alg);
    }

    kfree(hcrypt);
}