update madwifi

[linux-2.6/zen-sources.git] / drivers / net / wireless / madwifi / net80211 / ieee80211_crypto.c

/*-
 * Copyright (c) 2001 Atsushi Onoe
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id: ieee80211_crypto.c 3710 2008-06-06 20:32:29Z mentor $
 */
#ifndef EXPORT_SYMTAB
#define EXPORT_SYMTAB
#endif

/*
 * IEEE 802.11 generic crypto support.
 */
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/version.h>
#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/random.h>

#include "if_ethersubr.h"               /* for ETHER_HDR_LEN */
#include "if_media.h"

#include <net80211/ieee80211_var.h>

/*
 * Table of registered cipher modules.
 */
static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];

static int ieee80211_crypto_delkey_locked(struct ieee80211vap *,
        struct ieee80211_key *, struct ieee80211_node *);

/*
 * Default "null" key management routines.
 */
static ieee80211_keyix_t
null_key_alloc(struct ieee80211vap *vap, const struct ieee80211_key *k)
{
        return IEEE80211_KEYIX_NONE;
}
static int
null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k,
        struct ieee80211_node *ni)
{
        return 1;
}
static int
null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k,
        const u_int8_t mac[IEEE80211_ADDR_LEN])
{
        return 1;
}
static void null_key_update(struct ieee80211vap *vap)
{
}

#ifdef ATH_SUPERG_COMP
static void
null_comp_set(struct ieee80211vap *vap, struct ieee80211_node *ni,
        int en)
{
}
#endif

/*
 * Write-arounds for common operations.
 */
static __inline void
cipher_detach(struct ieee80211_key *key)
{
        key->wk_cipher->ic_detach(key);
}

static __inline void *
cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key)
{
        return key->wk_cipher->ic_attach(vap, key);
}

/* 
 * Wrappers for driver key management methods.
 */
static __inline ieee80211_keyix_t
dev_key_alloc(struct ieee80211vap *vap, const struct ieee80211_key *key)
{
        return vap->iv_key_alloc(vap, key);
}

static __inline int
dev_key_delete(struct ieee80211vap *vap,        const struct ieee80211_key *key,
        struct ieee80211_node *ni)
{
        return vap->iv_key_delete(vap, key, ni);
}

static __inline int
dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key,
        const u_int8_t mac[IEEE80211_ADDR_LEN])
{
        return vap->iv_key_set(vap, key, mac);
}

#ifdef ATH_SUPERG_COMP
static __inline void
dev_comp_set(struct ieee80211vap *vap, struct ieee80211_node *ni, int en)
{
        return vap->iv_comp_set(vap, ni, en);
}
#endif

/*
 * Setup crypto support for a device/shared instance.
 */
void
ieee80211_crypto_attach(struct ieee80211com *ic)
{
        /* NB: we assume everything is pre-zero'd */
        ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
}
EXPORT_SYMBOL(ieee80211_crypto_attach);

/*
 * Teardown crypto support.
 */
void
ieee80211_crypto_detach(struct ieee80211com *ic)
{
}
EXPORT_SYMBOL(ieee80211_crypto_detach);

/*
 * Setup crypto support for a VAP.
 */
void
ieee80211_crypto_vattach(struct ieee80211vap *vap)
{
        int i;

        /* NB: We assume everything is pre-zeroed */
        vap->iv_def_txkey = IEEE80211_KEYIX_NONE;
        for (i = 0; i < IEEE80211_WEP_NKID; i++)
                ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i],
                        IEEE80211_KEYIX_NONE);
        /*
         * Initialize the driver key support routines to noop entries.
         * This is useful especially for the cipher test modules.
         */
        vap->iv_key_alloc = null_key_alloc;
        vap->iv_key_set = null_key_set;
        vap->iv_key_delete = null_key_delete;
        vap->iv_key_update_begin = null_key_update;
        vap->iv_key_update_end = null_key_update;
#ifdef ATH_SUPERG_COMP
        vap->iv_comp_set = null_comp_set;
#endif
}
EXPORT_SYMBOL(ieee80211_crypto_vattach);

/*
 * Teardown crypto support for a vap.
 */
void
ieee80211_crypto_vdetach(struct ieee80211vap *vap)
{
        ieee80211_crypto_delglobalkeys(vap);
}
EXPORT_SYMBOL(ieee80211_crypto_vdetach);

/*
 * Register a crypto cipher module.
 */
void
ieee80211_crypto_register(const struct ieee80211_cipher *cip)
{
        if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
                printk(KERN_ERR "%s: cipher %s has an invalid cipher index %u\n",
                        __func__, cip->ic_name, cip->ic_cipher);
                return;
        }
        if ((ciphers[cip->ic_cipher] != NULL) && (ciphers[cip->ic_cipher] != cip)) {
                printk(KERN_ERR "%s: cipher %s registered with a different template\n",
                        __func__, cip->ic_name);
                return;
        }
        ciphers[cip->ic_cipher] = cip;
}
EXPORT_SYMBOL(ieee80211_crypto_register);

/*
 * Unregister a crypto cipher module.
 */
void
ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
{
        if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
                printk(KERN_ERR "%s: cipher %s has an invalid cipher index %u\n",
                        __func__, cip->ic_name, cip->ic_cipher);
                return;
        }
        if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
                printk(KERN_ERR "%s: cipher %s registered with a different template\n",
                        __func__, cip->ic_name);
                return;
        }
        /* NB: don't complain about not being registered */
        /* XXX: disallow if referenced */
        ciphers[cip->ic_cipher] = NULL;
}
EXPORT_SYMBOL(ieee80211_crypto_unregister);

/* XXX: well-known names! */
static const char *cipher_modnames[] = {
        "wlan_wep",     /* IEEE80211_CIPHER_WEP     */
        "wlan_tkip",    /* IEEE80211_CIPHER_TKIP    */
        "wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */
        "wlan_ccmp",    /* IEEE80211_CIPHER_AES_CCM */
        "wlan_ckip",    /* IEEE80211_CIPHER_CKIP    */
};


int
ieee80211_crypto_available(struct ieee80211vap *vap, u_int cipher)
{
        unsigned int status = 0;

        if (cipher < IEEE80211_CIPHER_MAX) {
                if (ciphers[cipher] == NULL) {
                        /*
                         * Auto-load cipher module if we have a well-known name
                         * for it.  It might be better to use string names rather
                         * than numbers and craft a module name based on the cipher
                         * name; e.g. wlan_cipher_<cipher-name>.
                         */
                        if (cipher < ARRAY_SIZE(cipher_modnames)) {
                                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                                "%s: unregistered cipher %u, load module %s\n",
                                                __func__, cipher, cipher_modnames[cipher]);
                                ieee80211_load_module(cipher_modnames[cipher]);

                                /*
                                 * If cipher module loaded it should immediately
                                 * call ieee80211_crypto_register which will fill
                                 * in the entry in the ciphers array.
                                 */
                                if (ciphers[cipher] == NULL) {
                                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                                        "%s: unable to load cipher %u, module %s\n",
                                                        __func__, cipher,
                                                        cipher < ARRAY_SIZE(cipher_modnames) ?
                                                        cipher_modnames[cipher] : "<unknown>");
                                        vap->iv_stats.is_crypto_nocipher++;
                                } else
                                        status = 1;
                        }
                } else
                        status = 1;
        }
        return status;
}
EXPORT_SYMBOL(ieee80211_crypto_available);

/*
 * Establish a relationship between the specified key and cipher
 * and, if necessary, allocate a hardware index from the driver.
 * Note that when a fixed key index is required it must be specified
 * and we blindly assign it w/o consulting the driver (XXX).
 *
 * This must be the first call applied to a key; all the other key
 * routines assume wk_cipher is setup.
 *
 * Locking must be handled by the caller using:
 *      ieee80211_key_update_begin(vap);
 *      ieee80211_key_update_end(vap);
 */
int
ieee80211_crypto_newkey(struct ieee80211vap *vap,
        int cipher, int flags, struct ieee80211_key *key)
{
        const struct ieee80211_cipher *cip;
        void *keyctx;
        int oflags;

        /*
         * Validate cipher and set reference to cipher routines.
         */
        if (cipher >= IEEE80211_CIPHER_MAX) {
                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                        "%s: invalid cipher %u\n", __func__, cipher);
                vap->iv_stats.is_crypto_badcipher++;
                return 0;
        }
        cip = ciphers[cipher];
        if (cip == NULL)
                return 0;

        oflags = key->wk_flags;
        flags &= IEEE80211_KEY_COMMON;
        /*
         * If the hardware does not support the cipher then
         * fallback to a host-based implementation.
         */
        if (!(vap->iv_caps & (1 << cipher))) {
                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                    "%s: no h/w support for cipher %s, falling back to s/w\n",
                    __func__, cip->ic_name);
                flags |= IEEE80211_KEY_SWCRYPT;
        }
        /*
         * Hardware TKIP with software MIC is an important
         * combination; we handle it by flagging each key,
         * the cipher modules honor it.
         */
        if (cipher == IEEE80211_CIPHER_TKIP) {
                if (!(vap->iv_caps & IEEE80211_C_TKIPMIC)) {
                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                "%s: no h/w support for TKIP MIC, falling back to s/w\n",
                                __func__);
                        flags |= IEEE80211_KEY_SWMIC;
                } else if (!((vap->iv_caps & IEEE80211_C_WME_TKIPMIC)) &&
                    (vap->iv_flags & IEEE80211_F_WME)) {
                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                "%s: no h/w support for TKIP MIC when WMM is turned on,"
                                " falling back to s/w\n",
                                __func__);
                        flags |= IEEE80211_KEY_SWMIC;
                }
        }

        /*
         * Bind cipher to key instance.  Note we do this
         * after checking the device capabilities so the
         * cipher module can optimize space usage based on
         * whether or not it needs to do the cipher work.
         */
        if ((key->wk_cipher != cip) || (key->wk_flags != flags)) {
again:
                /*
                 * Fill in the flags so cipher modules can see s/w
                 * crypto requirements and potentially allocate
                 * different state and/or attach different method
                 * pointers.
                 *
                 * XXX: This is not right when s/w crypto fallback
                 *      fails and we try to restore previous state.
                 */
                key->wk_flags = flags;
                keyctx = cip->ic_attach(vap, key);
                if (keyctx == NULL) {
                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                "%s: unable to attach cipher %s\n",
                                __func__, cip->ic_name);
                        key->wk_flags = oflags; /* restore old flags */
                        vap->iv_stats.is_crypto_attachfail++;
                        return 0;
                }
                cipher_detach(key);
                key->wk_cipher = cip;           /* XXX: refcnt? */
                key->wk_private = keyctx;
        }
        /*
         * Commit to requested usage so driver can see the flags.
         */
        key->wk_flags = flags;

        /*
         * Ask the driver for a key index if we don't have one.
         * Note that entries in the global key table always have
         * an index; this means it's safe to call this routine
         * for these entries just to setup the reference to the
         * cipher template.  Note also that when using software
         * crypto we also call the driver to give us a key index.
         */
        if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
                key->wk_keyix = dev_key_alloc(vap, key);
                if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
                        /*
                         * Driver has no room; fallback to doing crypto
                         * in the host.  We change the flags and start the
                         * procedure over.  If we get back here then there's
                         * no hope and we bail.  Note that this can leave
                         * the key in a inconsistent state if the caller
                         * continues to use it.
                         */
                        if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
                                vap->iv_stats.is_crypto_swfallback++;
                                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                        "%s: no h/w resources for cipher %s, "
                                        "falling back to s/w\n",
                                        __func__, cip->ic_name);
                                oflags = key->wk_flags;
                                flags |= IEEE80211_KEY_SWCRYPT;
                                if (cipher == IEEE80211_CIPHER_TKIP)
                                        flags |= IEEE80211_KEY_SWMIC;
                                goto again;
                        }
                        vap->iv_stats.is_crypto_keyfail++;
                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                "%s: unable to setup cipher %s\n",
                                __func__, cip->ic_name);
                        return 0;
                }
        }
        return 1;
}
EXPORT_SYMBOL(ieee80211_crypto_newkey);

/*
 * Remove the key (no locking, for internal use).
 */
static int
ieee80211_crypto_delkey_locked(struct ieee80211vap *vap, struct ieee80211_key *key,
        struct ieee80211_node *ni)
{
        ieee80211_keyix_t keyix;

        KASSERT(key->wk_cipher != NULL, ("No cipher!"));

        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                "%s: %s keyix %u flags 0x%x tsc %llu len %u\n", __func__,
                key->wk_cipher->ic_name, key->wk_keyix, key->wk_flags,
                (unsigned long long)key->wk_keytsc, key->wk_keylen);

        keyix = key->wk_keyix;
        if (keyix != IEEE80211_KEYIX_NONE) {
                /* Remove hardware entry. */
                /* XXX: key cache */
                if (!dev_key_delete(vap, key, ni)) {
                        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                                "%s: driver did not delete key index %u\n",
                                __func__, keyix);
                        vap->iv_stats.is_crypto_delkey++;
                        /* XXX: recovery? */
                }
        }
        cipher_detach(key);
        memset(key, 0, sizeof(*key));
        ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
        return 1;
}

/*
 * Remove the specified key.
 */
int
ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key,
        struct ieee80211_node *ni)
{
        int status;

#ifdef ATH_SUPERG_COMP
        /* If valid node entry is present cleanup the compression state */
        if (ni)
                dev_comp_set(vap, ni, 0);
#endif
        ieee80211_key_update_begin(vap);
        status = ieee80211_crypto_delkey_locked(vap, key, ni);
        ieee80211_key_update_end(vap);

        return status;
}
EXPORT_SYMBOL(ieee80211_crypto_delkey);

/*
 * Clear the global key table.
 */
void
ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
{
        int i;

        ieee80211_key_update_begin(vap);
        for (i = 0; i < IEEE80211_WEP_NKID; i++)
                (void) ieee80211_crypto_delkey_locked(vap, &vap->iv_nw_keys[i], NULL);
        ieee80211_key_update_end(vap);
}
EXPORT_SYMBOL(ieee80211_crypto_delglobalkeys);

/*
 * Set the contents of the specified key.
 *
 * Locking must be handled by the caller using:
 *      ieee80211_key_update_begin(vap);
 *      ieee80211_key_update_end(vap);
 */
int
ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key,
        const u_int8_t macaddr[IEEE80211_ADDR_LEN],
        struct ieee80211_node *ni)
{
        const struct ieee80211_cipher *cip = key->wk_cipher;
        int ret;

        KASSERT(cip != NULL, ("No cipher!"));

        IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                "%s: %s keyix %u flags 0x%x mac " MAC_FMT "  tsc %llu len %u\n", __func__,
                cip->ic_name, key->wk_keyix, key->wk_flags,
                MAC_ADDR(macaddr), (unsigned long long)key->wk_keytsc,
                key->wk_keylen);

        /*
         * Give cipher a chance to validate key contents.
         * XXX: Should happen before modifying state.
         */
        if (!cip->ic_setkey(key)) {
                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                        "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
                        __func__, cip->ic_name, key->wk_keyix,
                        key->wk_keylen, key->wk_flags);
                vap->iv_stats.is_crypto_setkey_cipher++;
                return 0;
        }
        if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
                /* NB: Nothing allocated, should not happen */
                IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
                        "%s: no key index; should not happen!\n", __func__);
                vap->iv_stats.is_crypto_setkey_nokey++;
                return 0;
        }
        ret = dev_key_set(vap, key, macaddr);
#ifdef ATH_SUPERG_COMP
        if (ret && ni) {
                /* Enable decompression only on receive key entries */
                if (key->wk_flags & IEEE80211_KEY_RECV)
                        dev_comp_set(vap, ni, 1);
        }
#endif

        return ret;
}
EXPORT_SYMBOL(ieee80211_crypto_setkey);

/*
 * Add privacy headers appropriate for the specified key.
 */
struct ieee80211_key *
ieee80211_crypto_encap(struct ieee80211_node *ni, struct sk_buff *skb)
{
        struct ieee80211vap *vap = ni->ni_vap;
        struct ieee80211_key *k;
        struct ieee80211_frame *wh;
        const struct ieee80211_cipher *cip;
        u_int8_t keyid;

        /*
         * Multicast traffic always uses the multicast key.
         * Otherwise if a unicast key is set we use that and
         * it is always key index 0.  When no unicast key is
         * set we fall back to the default transmit key.
         */
        wh = (struct ieee80211_frame *)skb->data;
        if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
            ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
                if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
                        IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
                                wh->i_addr1,
                                "no default transmit key (%s) deftxkey %u",
                                __func__, vap->iv_def_txkey);
                        vap->iv_stats.is_tx_nodefkey++;
                        return NULL;
                }
                keyid = vap->iv_def_txkey;
                k = &vap->iv_nw_keys[vap->iv_def_txkey];
        } else {
                keyid = 0;
                k = &ni->ni_ucastkey;
        }
        cip = k->wk_cipher;
        if (skb_headroom(skb) < cip->ic_header) {
                /*
                 * Should not happen; ieee80211_skbhdr_adjust should
                 * have allocated enough space for all headers.
                 */
                IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr1,
                        "%s: malformed packet for cipher %s; headroom %u",
                        __func__, cip->ic_name, skb_headroom(skb));
                vap->iv_stats.is_tx_noheadroom++;
                return NULL;
        }
        return (cip->ic_encap(k, skb, keyid << 6) ? k : NULL);
}
EXPORT_SYMBOL(ieee80211_crypto_encap);

/*
 * Validate and strip privacy headers (and trailer) for a
 * received frame that has the Protected Frame bit set.
 */
struct ieee80211_key *
ieee80211_crypto_decap(struct ieee80211_node *ni, struct sk_buff *skb, int hdrlen)
{
#define IEEE80211_WEP_HDRLEN    (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
#define IEEE80211_WEP_MINLEN \
        (sizeof(struct ieee80211_frame) + \
        IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
        struct ieee80211vap *vap = ni->ni_vap;
        struct ieee80211_key *k;
        struct ieee80211_frame *wh;
        const struct ieee80211_cipher *cip;
        const u_int8_t *ivp;
        u_int8_t keyid;

        /* NB: this minimum size data frame could be bigger */
        if (skb->len < IEEE80211_WEP_MINLEN) {
                IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
                        "%s: WEP data frame too short, len %u",
                        __func__, skb->len);
                vap->iv_stats.is_rx_tooshort++; /* XXX: unique stat? */
                return NULL;
        }
        /*
         * Locate the key. If unicast and there is no unicast
         * key then we fall back to the key id in the header.
         * This assumes unicast keys are only configured when
         * the key id in the header is meaningless (typically 0).
         */
        wh = (struct ieee80211_frame *)skb->data;
        ivp = skb->data + hdrlen;
        keyid = ivp[IEEE80211_WEP_IVLEN];
        if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
            ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none)
                k = &vap->iv_nw_keys[keyid >> 6];
        else
                k = &ni->ni_ucastkey;

        cip = k->wk_cipher;
        return (cip->ic_decap(k, skb, hdrlen) ? k : NULL);
#undef IEEE80211_WEP_MINLEN
#undef IEEE80211_WEP_HDRLEN
}
EXPORT_SYMBOL(ieee80211_crypto_decap);