lib80211.c

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/*
 * lib80211 -- common bits for IEEE802.11 drivers
 *
 * Copyright(c) 2008 John W. Linville <[email protected]>
 *
 * Portions copied from old ieee80211 component, w/ original copyright
 * notices below:
 *
 * Host AP crypto routines
 *
 * Copyright (c) 2002-2003, Jouni Malinen <[email protected]>
 * Portions Copyright (C) 2004, Intel Corporation <[email protected]>
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/ieee80211.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <net/lib80211.h>

#define DRV_NAME        "lib80211"

#define DRV_DESCRIPTION "common routines for IEEE802.11 drivers"

MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR("John W. Linville <[email protected]>");
MODULE_LICENSE("GPL");

struct lib80211_crypto_alg {
    struct list_head list;
    struct lib80211_crypto_ops *ops;
};

static LIST_HEAD(lib80211_crypto_algs);
static DEFINE_SPINLOCK(lib80211_crypto_lock);

static void lib80211_crypt_deinit_entries(struct lib80211_crypt_info *info,
                      int force);
static void lib80211_crypt_quiescing(struct lib80211_crypt_info *info);
static void lib80211_crypt_deinit_handler(unsigned long data);

const char *print_ssid(char *buf, const char *ssid, u8 ssid_len)
{
    const char *s = ssid;
    char *d = buf;

    ssid_len = min_t(u8, ssid_len, IEEE80211_MAX_SSID_LEN);
    while (ssid_len--) {
        if (isprint(*s)) {
            *d++ = *s++;
            continue;
        }

        *d++ = '\\';
        if (*s == '\0')
            *d++ = '0';
        else if (*s == '\n')
            *d++ = 'n';
        else if (*s == '\r')
            *d++ = 'r';
        else if (*s == '\t')
            *d++ = 't';
        else if (*s == '\\')
            *d++ = '\\';
        else
            d += snprintf(d, 3, "%03o", *s);
        s++;
    }
    *d = '\0';
    return buf;
}
EXPORT_SYMBOL(print_ssid);

int lib80211_crypt_info_init(struct lib80211_crypt_info *info, char *name,
                spinlock_t *lock)
{
    memset(info, 0, sizeof(*info));

    info->name = name;
    info->lock = lock;

    INIT_LIST_HEAD(&info->crypt_deinit_list);
    setup_timer(&info->crypt_deinit_timer, lib80211_crypt_deinit_handler,
            (unsigned long)info);

    return 0;
}
EXPORT_SYMBOL(lib80211_crypt_info_init);

void lib80211_crypt_info_free(struct lib80211_crypt_info *info)
{
    int i;

        lib80211_crypt_quiescing(info);
        del_timer_sync(&info->crypt_deinit_timer);
        lib80211_crypt_deinit_entries(info, 1);

        for (i = 0; i < NUM_WEP_KEYS; i++) {
                struct lib80211_crypt_data *crypt = info->crypt[i];
                if (crypt) {
                        if (crypt->ops) {
                                crypt->ops->deinit(crypt->priv);
                                module_put(crypt->ops->owner);
                        }
                        kfree(crypt);
                        info->crypt[i] = NULL;
                }
        }
}
EXPORT_SYMBOL(lib80211_crypt_info_free);

static void lib80211_crypt_deinit_entries(struct lib80211_crypt_info *info,
                      int force)
{
    struct lib80211_crypt_data *entry, *next;
    unsigned long flags;

    spin_lock_irqsave(info->lock, flags);
    list_for_each_entry_safe(entry, next, &info->crypt_deinit_list, list) {
        if (atomic_read(&entry->refcnt) != 0 && !force)
            continue;

        list_del(&entry->list);

        if (entry->ops) {
            entry->ops->deinit(entry->priv);
            module_put(entry->ops->owner);
        }
        kfree(entry);
    }
    spin_unlock_irqrestore(info->lock, flags);
}

/* After this, crypt_deinit_list won't accept new members */
static void lib80211_crypt_quiescing(struct lib80211_crypt_info *info)
{
    unsigned long flags;

    spin_lock_irqsave(info->lock, flags);
    info->crypt_quiesced = 1;
    spin_unlock_irqrestore(info->lock, flags);
}

static void lib80211_crypt_deinit_handler(unsigned long data)
{
    struct lib80211_crypt_info *info = (struct lib80211_crypt_info *)data;
    unsigned long flags;

    lib80211_crypt_deinit_entries(info, 0);

    spin_lock_irqsave(info->lock, flags);
    if (!list_empty(&info->crypt_deinit_list) && !info->crypt_quiesced) {
        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);
}

void lib80211_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);
    if (!info->crypt_quiesced) {
        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(lib80211_crypt_delayed_deinit);

int lib80211_register_crypto_ops(struct lib80211_crypto_ops *ops)
{
    unsigned long flags;
    struct lib80211_crypto_alg *alg;

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

    alg->ops = ops;

    spin_lock_irqsave(&lib80211_crypto_lock, flags);
    list_add(&alg->list, &lib80211_crypto_algs);
    spin_unlock_irqrestore(&lib80211_crypto_lock, flags);

    printk(KERN_DEBUG "lib80211_crypt: registered algorithm '%s'\n",
           ops->name);

    return 0;
}
EXPORT_SYMBOL(lib80211_register_crypto_ops);

int lib80211_unregister_crypto_ops(struct lib80211_crypto_ops *ops)
{
    struct lib80211_crypto_alg *alg;
    unsigned long flags;

    spin_lock_irqsave(&lib80211_crypto_lock, flags);
    list_for_each_entry(alg, &lib80211_crypto_algs, list) {
        if (alg->ops == ops)
            goto found;
    }
    spin_unlock_irqrestore(&lib80211_crypto_lock, flags);
    return -EINVAL;

      found:
    printk(KERN_DEBUG "lib80211_crypt: unregistered algorithm '%s'\n",
           ops->name);
    list_del(&alg->list);
    spin_unlock_irqrestore(&lib80211_crypto_lock, flags);
    kfree(alg);
    return 0;
}
EXPORT_SYMBOL(lib80211_unregister_crypto_ops);

struct lib80211_crypto_ops *lib80211_get_crypto_ops(const char *name)
{
    struct lib80211_crypto_alg *alg;
    unsigned long flags;

    spin_lock_irqsave(&lib80211_crypto_lock, flags);
    list_for_each_entry(alg, &lib80211_crypto_algs, list) {
        if (strcmp(alg->ops->name, name) == 0)
            goto found;
    }
    spin_unlock_irqrestore(&lib80211_crypto_lock, flags);
    return NULL;

      found:
    spin_unlock_irqrestore(&lib80211_crypto_lock, flags);
    return alg->ops;
}
EXPORT_SYMBOL(lib80211_get_crypto_ops);

static void *lib80211_crypt_null_init(int keyidx)
{
    return (void *)1;
}

static void lib80211_crypt_null_deinit(void *priv)
{
}

static struct lib80211_crypto_ops lib80211_crypt_null = {
    .name = "NULL",
    .init = lib80211_crypt_null_init,
    .deinit = lib80211_crypt_null_deinit,
    .owner = THIS_MODULE,
};

static int __init lib80211_init(void)
{
    pr_info(DRV_DESCRIPTION "\n");
    return lib80211_register_crypto_ops(&lib80211_crypt_null);
}

static void __exit lib80211_exit(void)
{
    lib80211_unregister_crypto_ops(&lib80211_crypt_null);
    BUG_ON(!list_empty(&lib80211_crypto_algs));
}

module_init(lib80211_init);
module_exit(lib80211_exit);