xref: /freebsd/sys/dev/ath/if_ath_keycache.c (revision cc637103f69892f4a7f4ef82d4787e180e1692be)

/*-
 * Copyright (c) 2002-2009 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,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 *    redistribution must be conditioned upon including a substantially
 *    similar Disclaimer requirement for further binary redistribution.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * Driver for the Atheros Wireless LAN controller.
 *
 * This software is derived from work of Atsushi Onoe; his contribution
 * is greatly appreciated.
 */

#include "opt_inet.h"
#include "opt_ath.h"
#include "opt_wlan.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/callout.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kthread.h>
#include <sys/taskqueue.h>
#include <sys/priv.h>

#include <machine/bus.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_llc.h>

#include <net80211/ieee80211_var.h>

#include <net/bpf.h>

#include <dev/ath/if_athvar.h>

#include <dev/ath/if_ath_debug.h>
#include <dev/ath/if_ath_keycache.h>

#ifdef ATH_DEBUG
static void
ath_keyprint(struct ath_softc *sc, const char *tag, u_int ix,
	const HAL_KEYVAL *hk, const u_int8_t mac[IEEE80211_ADDR_LEN])
{
	static const char *ciphers[] = {
		"WEP",
		"AES-OCB",
		"AES-CCM",
		"CKIP",
		"TKIP",
		"CLR",
	};
	int i, n;

	printf("%s: [%02u] %-7s ", tag, ix, ciphers[hk->kv_type]);
	for (i = 0, n = hk->kv_len; i < n; i++)
		printf("%02x", hk->kv_val[i]);
	printf(" mac %s", ether_sprintf(mac));
	if (hk->kv_type == HAL_CIPHER_TKIP) {
		printf(" %s ", sc->sc_splitmic ? "mic" : "rxmic");
		for (i = 0; i < sizeof(hk->kv_mic); i++)
			printf("%02x", hk->kv_mic[i]);
		if (!sc->sc_splitmic) {
			printf(" txmic ");
			for (i = 0; i < sizeof(hk->kv_txmic); i++)
				printf("%02x", hk->kv_txmic[i]);
		}
	}
	printf("\n");
}
#endif

/*
 * Set a TKIP key into the hardware.  This handles the
 * potential distribution of key state to multiple key
 * cache slots for TKIP.
 */
static int
ath_keyset_tkip(struct ath_softc *sc, const struct ieee80211_key *k,
	HAL_KEYVAL *hk, const u_int8_t mac[IEEE80211_ADDR_LEN])
{
#define	IEEE80211_KEY_XR	(IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV)
	static const u_int8_t zerobssid[IEEE80211_ADDR_LEN];
	struct ath_hal *ah = sc->sc_ah;

	KASSERT(k->wk_cipher->ic_cipher == IEEE80211_CIPHER_TKIP,
		("got a non-TKIP key, cipher %u", k->wk_cipher->ic_cipher));
	if ((k->wk_flags & IEEE80211_KEY_XR) == IEEE80211_KEY_XR) {
		if (sc->sc_splitmic) {
			/*
			 * TX key goes at first index, RX key at the rx index.
			 * The hal handles the MIC keys at index+64.
			 */
			memcpy(hk->kv_mic, k->wk_txmic, sizeof(hk->kv_mic));
			KEYPRINTF(sc, k->wk_keyix, hk, zerobssid);
			if (!ath_hal_keyset(ah, k->wk_keyix, hk, zerobssid))
				return 0;

			memcpy(hk->kv_mic, k->wk_rxmic, sizeof(hk->kv_mic));
			KEYPRINTF(sc, k->wk_keyix+32, hk, mac);
			/* XXX delete tx key on failure? */
			return ath_hal_keyset(ah, k->wk_keyix+32, hk, mac);
		} else {
			/*
			 * Room for both TX+RX MIC keys in one key cache
			 * slot, just set key at the first index; the hal
			 * will handle the rest.
			 */
			memcpy(hk->kv_mic, k->wk_rxmic, sizeof(hk->kv_mic));
			memcpy(hk->kv_txmic, k->wk_txmic, sizeof(hk->kv_txmic));
			KEYPRINTF(sc, k->wk_keyix, hk, mac);
			return ath_hal_keyset(ah, k->wk_keyix, hk, mac);
		}
	} else if (k->wk_flags & IEEE80211_KEY_XMIT) {
		if (sc->sc_splitmic) {
			/*
			 * NB: must pass MIC key in expected location when
			 * the keycache only holds one MIC key per entry.
			 */
			memcpy(hk->kv_mic, k->wk_txmic, sizeof(hk->kv_txmic));
		} else
			memcpy(hk->kv_txmic, k->wk_txmic, sizeof(hk->kv_txmic));
		KEYPRINTF(sc, k->wk_keyix, hk, mac);
		return ath_hal_keyset(ah, k->wk_keyix, hk, mac);
	} else if (k->wk_flags & IEEE80211_KEY_RECV) {
		memcpy(hk->kv_mic, k->wk_rxmic, sizeof(hk->kv_mic));
		KEYPRINTF(sc, k->wk_keyix, hk, mac);
		return ath_hal_keyset(ah, k->wk_keyix, hk, mac);
	}
	return 0;
#undef IEEE80211_KEY_XR
}

/*
 * Set a net80211 key into the hardware.  This handles the
 * potential distribution of key state to multiple key
 * cache slots for TKIP with hardware MIC support.
 */
int
ath_keyset(struct ath_softc *sc, struct ieee80211vap *vap,
	const struct ieee80211_key *k,
	struct ieee80211_node *bss)
{
#define	N(a)	(sizeof(a)/sizeof(a[0]))
	static const u_int8_t ciphermap[] = {
		HAL_CIPHER_WEP,		/* IEEE80211_CIPHER_WEP */
		HAL_CIPHER_TKIP,	/* IEEE80211_CIPHER_TKIP */
		HAL_CIPHER_AES_OCB,	/* IEEE80211_CIPHER_AES_OCB */
		HAL_CIPHER_AES_CCM,	/* IEEE80211_CIPHER_AES_CCM */
		(u_int8_t) -1,		/* 4 is not allocated */
		HAL_CIPHER_CKIP,	/* IEEE80211_CIPHER_CKIP */
		HAL_CIPHER_CLR,		/* IEEE80211_CIPHER_NONE */
	};
	struct ath_hal *ah = sc->sc_ah;
	const struct ieee80211_cipher *cip = k->wk_cipher;
	u_int8_t gmac[IEEE80211_ADDR_LEN];
	const u_int8_t *mac;
	HAL_KEYVAL hk;

	memset(&hk, 0, sizeof(hk));
	/*
	 * Software crypto uses a "clear key" so non-crypto
	 * state kept in the key cache are maintained and
	 * so that rx frames have an entry to match.
	 */
	if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
		KASSERT(cip->ic_cipher < N(ciphermap),
			("invalid cipher type %u", cip->ic_cipher));
		hk.kv_type = ciphermap[cip->ic_cipher];
		hk.kv_len = k->wk_keylen;
		memcpy(hk.kv_val, k->wk_key, k->wk_keylen);
	} else
		hk.kv_type = HAL_CIPHER_CLR;

	/*
	 * If we're installing a clear cipher key and
	 * the hardware doesn't support that, just succeed.
	 * Leave it up to the net80211 layer to figure it out.
	 */
	if (hk.kv_type == HAL_CIPHER_CLR && sc->sc_hasclrkey == 0) {
		return (1);
	}

	/*
	 * XXX TODO: check this:
	 *
	 * Group keys on hardware that supports multicast frame
	 * key search should only be done in adhoc/hostap mode,
	 * not STA mode.
	 *
	 * XXX TODO: what about mesh, tdma?
	 */
#if 0
	if ((vap->iv_opmode == IEEE80211_M_HOSTAP ||
	     vap->iv_opmode == IEEE80211_M_IBSS) &&
#else
	if (
#endif
	    (k->wk_flags & IEEE80211_KEY_GROUP) &&
	    sc->sc_mcastkey) {
		/*
		 * Group keys on hardware that supports multicast frame
		 * key search use a MAC that is the sender's address with
		 * the multicast bit set instead of the app-specified address.
		 */
		IEEE80211_ADDR_COPY(gmac, bss->ni_macaddr);
		gmac[0] |= 0x01;
		mac = gmac;
	} else
		mac = k->wk_macaddr;

	if (hk.kv_type == HAL_CIPHER_TKIP &&
	    (k->wk_flags & IEEE80211_KEY_SWMIC) == 0) {
		return ath_keyset_tkip(sc, k, &hk, mac);
	} else {
		KEYPRINTF(sc, k->wk_keyix, &hk, mac);
		return ath_hal_keyset(ah, k->wk_keyix, &hk, mac);
	}
#undef N
}

/*
 * Allocate tx/rx key slots for TKIP.  We allocate two slots for
 * each key, one for decrypt/encrypt and the other for the MIC.
 */
static u_int16_t
key_alloc_2pair(struct ath_softc *sc,
	ieee80211_keyix *txkeyix, ieee80211_keyix *rxkeyix)
{
#define	N(a)	(sizeof(a)/sizeof(a[0]))
	u_int i, keyix;

	KASSERT(sc->sc_splitmic, ("key cache !split"));
	/* XXX could optimize */
	for (i = 0; i < N(sc->sc_keymap)/4; i++) {
		u_int8_t b = sc->sc_keymap[i];
		if (b != 0xff) {
			/*
			 * One or more slots in this byte are free.
			 */
			keyix = i*NBBY;
			while (b & 1) {
		again:
				keyix++;
				b >>= 1;
			}
			/* XXX IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV */
			if (isset(sc->sc_keymap, keyix+32) ||
			    isset(sc->sc_keymap, keyix+64) ||
			    isset(sc->sc_keymap, keyix+32+64)) {
				/* full pair unavailable */
				/* XXX statistic */
				if (keyix == (i+1)*NBBY) {
					/* no slots were appropriate, advance */
					continue;
				}
				goto again;
			}
			setbit(sc->sc_keymap, keyix);
			setbit(sc->sc_keymap, keyix+64);
			setbit(sc->sc_keymap, keyix+32);
			setbit(sc->sc_keymap, keyix+32+64);
			DPRINTF(sc, ATH_DEBUG_KEYCACHE,
				"%s: key pair %u,%u %u,%u\n",
				__func__, keyix, keyix+64,
				keyix+32, keyix+32+64);
			*txkeyix = keyix;
			*rxkeyix = keyix+32;
			return 1;
		}
	}
	DPRINTF(sc, ATH_DEBUG_KEYCACHE, "%s: out of pair space\n", __func__);
	return 0;
#undef N
}

/*
 * Allocate tx/rx key slots for TKIP.  We allocate two slots for
 * each key, one for decrypt/encrypt and the other for the MIC.
 */
static u_int16_t
key_alloc_pair(struct ath_softc *sc,
	ieee80211_keyix *txkeyix, ieee80211_keyix *rxkeyix)
{
#define	N(a)	(sizeof(a)/sizeof(a[0]))
	u_int i, keyix;

	KASSERT(!sc->sc_splitmic, ("key cache split"));
	/* XXX could optimize */
	for (i = 0; i < N(sc->sc_keymap)/4; i++) {
		u_int8_t b = sc->sc_keymap[i];
		if (b != 0xff) {
			/*
			 * One or more slots in this byte are free.
			 */
			keyix = i*NBBY;
			while (b & 1) {
		again:
				keyix++;
				b >>= 1;
			}
			if (isset(sc->sc_keymap, keyix+64)) {
				/* full pair unavailable */
				/* XXX statistic */
				if (keyix == (i+1)*NBBY) {
					/* no slots were appropriate, advance */
					continue;
				}
				goto again;
			}
			setbit(sc->sc_keymap, keyix);
			setbit(sc->sc_keymap, keyix+64);
			DPRINTF(sc, ATH_DEBUG_KEYCACHE,
				"%s: key pair %u,%u\n",
				__func__, keyix, keyix+64);
			*txkeyix = *rxkeyix = keyix;
			return 1;
		}
	}
	DPRINTF(sc, ATH_DEBUG_KEYCACHE, "%s: out of pair space\n", __func__);
	return 0;
#undef N
}

/*
 * Allocate a single key cache slot.
 */
static int
key_alloc_single(struct ath_softc *sc,
	ieee80211_keyix *txkeyix, ieee80211_keyix *rxkeyix)
{
#define	N(a)	(sizeof(a)/sizeof(a[0]))
	u_int i, keyix;

	if (sc->sc_hasclrkey == 0) {
		/*
		 * Map to slot 0 for the AR5210.
		 */
		*txkeyix = *rxkeyix = 0;
		return (1);
	}

	/* XXX try i,i+32,i+64,i+32+64 to minimize key pair conflicts */
	for (i = 0; i < N(sc->sc_keymap); i++) {
		u_int8_t b = sc->sc_keymap[i];
		if (b != 0xff) {
			/*
			 * One or more slots are free.
			 */
			keyix = i*NBBY;
			while (b & 1)
				keyix++, b >>= 1;
			setbit(sc->sc_keymap, keyix);
			DPRINTF(sc, ATH_DEBUG_KEYCACHE, "%s: key %u\n",
				__func__, keyix);
			*txkeyix = *rxkeyix = keyix;
			return 1;
		}
	}
	DPRINTF(sc, ATH_DEBUG_KEYCACHE, "%s: out of space\n", __func__);
	return 0;
#undef N
}

/*
 * Allocate one or more key cache slots for a uniacst key.  The
 * key itself is needed only to identify the cipher.  For hardware
 * TKIP with split cipher+MIC keys we allocate two key cache slot
 * pairs so that we can setup separate TX and RX MIC keys.  Note
 * that the MIC key for a TKIP key at slot i is assumed by the
 * hardware to be at slot i+64.  This limits TKIP keys to the first
 * 64 entries.
 */
int
ath_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k,
	ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
{
	struct ath_softc *sc = vap->iv_ic->ic_ifp->if_softc;

	/*
	 * Group key allocation must be handled specially for
	 * parts that do not support multicast key cache search
	 * functionality.  For those parts the key id must match
	 * the h/w key index so lookups find the right key.  On
	 * parts w/ the key search facility we install the sender's
	 * mac address (with the high bit set) and let the hardware
	 * find the key w/o using the key id.  This is preferred as
	 * it permits us to support multiple users for adhoc and/or
	 * multi-station operation.
	 */
	if (k->wk_keyix != IEEE80211_KEYIX_NONE) {
		/*
		 * Only global keys should have key index assigned.
		 */
		if (!(&vap->iv_nw_keys[0] <= k &&
		      k < &vap->iv_nw_keys[IEEE80211_WEP_NKID])) {
			/* should not happen */
			DPRINTF(sc, ATH_DEBUG_KEYCACHE,
				"%s: bogus group key\n", __func__);
			return 0;
		}
		if (vap->iv_opmode != IEEE80211_M_HOSTAP ||
		    !(k->wk_flags & IEEE80211_KEY_GROUP) ||
		    !sc->sc_mcastkey) {
			/*
			 * XXX we pre-allocate the global keys so
			 * have no way to check if they've already
			 * been allocated.
			 */
			*keyix = *rxkeyix = k - vap->iv_nw_keys;
			return 1;
		}
		/*
		 * Group key and device supports multicast key search.
		 */
		k->wk_keyix = IEEE80211_KEYIX_NONE;
	}

	/*
	 * We allocate two pair for TKIP when using the h/w to do
	 * the MIC.  For everything else, including software crypto,
	 * we allocate a single entry.  Note that s/w crypto requires
	 * a pass-through slot on the 5211 and 5212.  The 5210 does
	 * not support pass-through cache entries and we map all
	 * those requests to slot 0.
	 */
	if (k->wk_flags & IEEE80211_KEY_SWCRYPT) {
		return key_alloc_single(sc, keyix, rxkeyix);
	} else if (k->wk_cipher->ic_cipher == IEEE80211_CIPHER_TKIP &&
	    (k->wk_flags & IEEE80211_KEY_SWMIC) == 0) {
		if (sc->sc_splitmic)
			return key_alloc_2pair(sc, keyix, rxkeyix);
		else
			return key_alloc_pair(sc, keyix, rxkeyix);
	} else {
		return key_alloc_single(sc, keyix, rxkeyix);
	}
}

/*
 * Delete an entry in the key cache allocated by ath_key_alloc.
 */
int
ath_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k)
{
	struct ath_softc *sc = vap->iv_ic->ic_ifp->if_softc;
	struct ath_hal *ah = sc->sc_ah;
	const struct ieee80211_cipher *cip = k->wk_cipher;
	u_int keyix = k->wk_keyix;

	DPRINTF(sc, ATH_DEBUG_KEYCACHE, "%s: delete key %u\n", __func__, keyix);

	ath_hal_keyreset(ah, keyix);
	/*
	 * Handle split tx/rx keying required for TKIP with h/w MIC.
	 */
	if (cip->ic_cipher == IEEE80211_CIPHER_TKIP &&
	    (k->wk_flags & IEEE80211_KEY_SWMIC) == 0 && sc->sc_splitmic)
		ath_hal_keyreset(ah, keyix+32);		/* RX key */
	if (keyix >= IEEE80211_WEP_NKID) {
		/*
		 * Don't touch keymap entries for global keys so
		 * they are never considered for dynamic allocation.
		 */
		clrbit(sc->sc_keymap, keyix);
		if (cip->ic_cipher == IEEE80211_CIPHER_TKIP &&
		    (k->wk_flags & IEEE80211_KEY_SWMIC) == 0) {
			clrbit(sc->sc_keymap, keyix+64);	/* TX key MIC */
			if (sc->sc_splitmic) {
				/* +32 for RX key, +32+64 for RX key MIC */
				clrbit(sc->sc_keymap, keyix+32);
				clrbit(sc->sc_keymap, keyix+32+64);
			}
		}
	}
	return 1;
}

/*
 * Set the key cache contents for the specified key.  Key cache
 * slot(s) must already have been allocated by ath_key_alloc.
 */
int
ath_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k,
	const u_int8_t mac[IEEE80211_ADDR_LEN])
{
	struct ath_softc *sc = vap->iv_ic->ic_ifp->if_softc;

	return ath_keyset(sc, vap, k, vap->iv_bss);
}