io/net80211/net80211_crypto_tkip.c

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2001 Atsushi Onoe
 * Copyright (c) 2002-2008 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.
 */

/*
 * IEEE 802.11i TKIP crypto support.
 *
 * Part of this module is derived from similar code in the Host
 * AP driver. The code is used with the consent of the author and
 * it's license is included below.
 */

#include <sys/byteorder.h>
#include <sys/crypto/common.h>
#include <sys/crypto/api.h>
#include <sys/crc32.h>
#include <sys/random.h>
#include <sys/strsun.h>
#include "net80211_impl.h"

static void *tkip_attach(struct ieee80211com *, struct ieee80211_key *);
static void tkip_detach(struct ieee80211_key *);
static int tkip_setkey(struct ieee80211_key *);
static int tkip_encap(struct ieee80211_key *, mblk_t *, uint8_t);
static int tkip_decap(struct ieee80211_key *, mblk_t *, int);
static int tkip_enmic(struct ieee80211_key *, mblk_t *, int);
static int tkip_demic(struct ieee80211_key *, mblk_t *, int);

const struct ieee80211_cipher tkip  = {
    "TKIP",
    IEEE80211_CIPHER_TKIP,
    IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
        IEEE80211_WEP_EXTIVLEN,
    IEEE80211_WEP_CRCLEN,
    IEEE80211_WEP_MICLEN,
    tkip_attach,
    tkip_detach,
    tkip_setkey,
    tkip_encap,
    tkip_decap,
    tkip_enmic,
    tkip_demic,
};

struct tkip_ctx {
    struct ieee80211com *tc_ic;     /* for diagnostics */
    uint16_t        tx_ttak[5];
    int         tx_phase1_done;
    uint8_t         tx_rc4key[16];
    uint16_t        rx_ttak[5];
    int         rx_phase1_done;
    uint8_t         rx_rc4key[16];
    uint64_t        rx_rsc;     /* held until MIC verified */
};

static void michael_mic(struct tkip_ctx *, const uint8_t *,
    mblk_t *, uint_t, size_t, uint8_t[]);
static int tkip_encrypt(struct tkip_ctx *, struct ieee80211_key *,
    mblk_t *, int);
static int tkip_decrypt(struct tkip_ctx *, struct ieee80211_key *,
    mblk_t *, int);

extern int rc4_init(crypto_context_t *, const uint8_t *, int);
extern int rc4_crypt(crypto_context_t, const uint8_t *, uint8_t *, int);
extern int rc4_final(crypto_context_t, uint8_t *, int);

/* ARGSUSED */
static void *
tkip_attach(struct ieee80211com *ic, struct ieee80211_key *k)
{
    struct tkip_ctx *ctx;

    ctx = kmem_zalloc(sizeof (struct tkip_ctx), KM_SLEEP);
    if (ctx == NULL)
        return (NULL);

    ctx->tc_ic = ic;
    return (ctx);
}

static void
tkip_detach(struct ieee80211_key *k)
{
    struct tkip_ctx *ctx = k->wk_private;

    if (ctx != NULL)
        kmem_free(ctx, sizeof (struct tkip_ctx));
}

static int
tkip_setkey(struct ieee80211_key *k)
{
    if (k->wk_keylen != (128/NBBY))
        return (0);

    k->wk_keytsc = 1;       /* TSC starts at 1 */
    return (1);
}

/*
 * Add privacy headers appropriate for the specified key.
 */
static int
tkip_encap(struct ieee80211_key *k, mblk_t *mp, uint8_t keyid)
{
    struct tkip_ctx *ctx = k->wk_private;
    struct ieee80211com *ic = ctx->tc_ic;
    uint8_t *ivp;
    int hdrlen;

    /*
     * Handle TKIP counter measures requirement.
     */
    if (ic->ic_flags & IEEE80211_F_COUNTERM)
        return (0);

    hdrlen = ieee80211_hdrspace(ic, mp->b_rptr);
    /*
     * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
     */
    ivp = mp->b_rptr;
    ivp += hdrlen;

    ivp[0] = k->wk_keytsc >> 8;     /* TSC1 */
    ivp[1] = (ivp[0] | 0x20) & 0x7f;    /* WEP seed */
    ivp[2] = k->wk_keytsc >> 0;     /* TSC0 */
    ivp[3] = keyid | IEEE80211_WEP_EXTIV;   /* KeyID | ExtID */
    ivp[4] = k->wk_keytsc >> 16;        /* TSC2 */
    ivp[5] = k->wk_keytsc >> 24;        /* TSC3 */
    ivp[6] = k->wk_keytsc >> 32;        /* TSC4 */
    ivp[7] = k->wk_keytsc >> 40;        /* TSC5 */

    /*
     * Finally, do software encrypt if neeed.
     */
    if (k->wk_flags & IEEE80211_KEY_SWCRYPT) {
        if (!tkip_encrypt(ctx, k, mp, hdrlen))
            return (0);
    } else
        k->wk_keytsc++;     /* wrap at 48 bits */

    return (1);
}

uint64_t
ieee80211_read_6(uint8_t b0, uint8_t b1, uint8_t b2,
    uint8_t b3, uint8_t b4, uint8_t b5)
{
    uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
    uint16_t iv16 = (b4 << 0) | (b5 << 8);
    return ((((uint64_t)iv16) << 32) | iv32);
}

/*
 * Validate and strip privacy headers (and trailer) for a
 * received frame.  If necessary, decrypt the frame using
 * the specified key.
 */
static int
tkip_decap(struct ieee80211_key *k, mblk_t *mp, int hdrlen)
{
    struct tkip_ctx *ctx = k->wk_private;
    struct ieee80211com *ic = ctx->tc_ic;
    uint8_t *ivp;
    uint64_t pn;

    /*
     * Header should have extended IV and sequence number;
     * verify the former and validate the latter.
     */
    ivp = mp->b_rptr + hdrlen;
    if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
        /*
         * No extended IV; discard frame.
         */
        return (0);
    }
    /*
     * Handle TKIP counter measures requirement.
     */
    if (ic->ic_flags & IEEE80211_F_COUNTERM)
        return (0);

    /* NB: assume IEEEE80211_WEP_MINLEN covers the extended IV */
    pn = ieee80211_read_6(ivp[2], ivp[0], ivp[4], ivp[5], ivp[6], ivp[7]);
    ctx->rx_rsc = pn;
    if (ctx->rx_rsc <= k->wk_keyrsc)
        return (0);
    /*
     * NB: We can't update the rsc in the key until MIC is verified.
     *
     * We assume we are not preempted between doing the check above
     * and updating wk_keyrsc when stripping the MIC in tkip_demic.
     * Otherwise we might process another packet and discard it as
     * a replay.
     */

    /*
     * Check if the device handled the decrypt in hardware.
     * If so we just strip the header; otherwise we need to
     * handle the decrypt in software.
     */
    if (k->wk_flags & IEEE80211_KEY_SWCRYPT) {
        if (!tkip_decrypt(ctx, k, mp, hdrlen))
            return (0);
    }

    /*
     * Copy up 802.11 header and strip crypto bits.
     */
    (void) memmove(mp->b_rptr + tkip.ic_header, mp->b_rptr, hdrlen);
    mp->b_rptr += tkip.ic_header;
    mp->b_wptr -= tkip.ic_trailer;

    return (1);
}

/*
 * Add MIC to the frame as needed.
 */
static int
tkip_enmic(struct ieee80211_key *k, mblk_t *mp, int force)
{
    struct tkip_ctx *ctx = k->wk_private;

    if (force || (k->wk_flags & IEEE80211_KEY_SWMIC)) {
        int hdrlen;
        uint8_t *mic;

        hdrlen = ieee80211_hdrspace(ctx->tc_ic, mp->b_rptr);
        mic = mp->b_wptr;
        mp->b_wptr += tkip.ic_miclen;

        if ((int)(MBLKL(mp) -
            (hdrlen + tkip.ic_header + tkip.ic_miclen)) < 0)
            return (0); /* dead packet */

        michael_mic(ctx, k->wk_txmic, mp, (hdrlen + tkip.ic_header),
            MBLKL(mp) -
            (hdrlen + tkip.ic_header + tkip.ic_miclen), mic);
    }
    return (1);
}

/*
 * Verify and strip MIC from the frame.
 */
/* ARGSUSED */
static int
tkip_demic(struct ieee80211_key *k, mblk_t *mp, int force)
{
    struct tkip_ctx *ctx = k->wk_private;

    if (force || (k->wk_flags & IEEE80211_KEY_SWMIC)) {
        int hdrlen = ieee80211_hdrspace(ctx->tc_ic, mp->b_rptr);
        uint8_t mic[IEEE80211_WEP_MICLEN];
        uint8_t mic0[IEEE80211_WEP_MICLEN];

        michael_mic(ctx, k->wk_rxmic,
            mp, hdrlen,
            MBLKL(mp) - (hdrlen + tkip.ic_miclen),
            mic);
        bcopy(mp->b_wptr - tkip.ic_miclen, mic0, tkip.ic_miclen);
        if (bcmp(mic, mic0, tkip.ic_miclen)) {
            ieee80211_dbg(IEEE80211_MSG_CRYPTO,
                "tkip_demic() mic mismatch\n");
            return (0);
        }
    }
    /*
     * Strip MIC from the tail.
     */
    mp->b_wptr -= tkip.ic_miclen;
    /*
     * Ok to update rsc now that MIC has been verified.
     */
    k->wk_keyrsc = ctx->rx_rsc;
    return (1);
}

/*
 * For the avoidance of doubt, except that if any license choice other
 * than GPL or LGPL is available it will apply instead, Sun elects to
 * use only the General Public License version 2 (GPLv2) at this time
 * for any software where a choice of GPL license versions is made
 * available with the language indicating that GPLv2 or any later
 * version may be used, or where a choice of which version of the GPL
 * is applied is otherwise unspecified.
 */

/*
 * Host AP crypt: host-based TKIP encryption implementation for Host AP driver
 *
 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
 *
 * 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.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 */

/* Table of CRCs of all 8-bit messages */
static uint32_t crc_table[] = { CRC32_TABLE };

static uint16_t
RotR1(uint16_t val)
{
    return ((val >> 1) | (val << 15));
}

static uint8_t
Lo8(uint16_t val)
{
    return (val & 0xff);
}

static uint8_t
Hi8(uint16_t val)
{
    return (val >> 8);
}

static uint16_t
Lo16(uint32_t val)
{
    return (val & 0xffff);
}

static uint16_t
Hi16(uint32_t val)
{
    return (val >> 16);
}

static uint16_t
Mk16(uint8_t hi, uint8_t lo)
{
    return (lo | (((uint16_t)hi) << 8));
}

static uint16_t
Mk16_le(const uint16_t *v)
{
    return (LE_16(*v));
}

static const uint16_t Sbox[256] = {
    0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
    0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
    0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
    0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
    0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
    0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
    0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
    0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
    0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
    0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
    0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
    0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
    0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
    0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
    0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
    0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
    0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
    0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
    0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
    0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
    0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
    0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
    0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
    0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
    0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
    0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
    0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
    0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
    0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
    0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
    0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
    0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
};

static uint16_t
_S_(uint16_t v)
{
    uint16_t t = Sbox[Hi8(v)];
    return (Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8)));
}

#define PHASE1_LOOP_COUNT   8

static void
tkip_mixing_phase1(uint16_t *TTAK, const uint8_t *TK,
    const uint8_t *TA, uint32_t IV32)
{
    int i, j;

    /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
    TTAK[0] = Lo16(IV32);
    TTAK[1] = Hi16(IV32);
    TTAK[2] = Mk16(TA[1], TA[0]);
    TTAK[3] = Mk16(TA[3], TA[2]);
    TTAK[4] = Mk16(TA[5], TA[4]);

    for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
        j = 2 * (i & 1);
        TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
        TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
        TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
        TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
        TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
    }
}

static void
tkip_mixing_phase2(uint8_t *WEPSeed, const uint8_t *TK,
    const uint16_t *TTAK, uint16_t IV16)
{
    /*
     * Make temporary area overlap WEP seed so that the final copy can be
     * avoided on little endian hosts.
     */
    uint16_t *PPK = (uint16_t *)&WEPSeed[4];

    /* Step 1 - make copy of TTAK and bring in TSC */
    PPK[0] = TTAK[0];
    PPK[1] = TTAK[1];
    PPK[2] = TTAK[2];
    PPK[3] = TTAK[3];
    PPK[4] = TTAK[4];
    PPK[5] = TTAK[4] + IV16;

    /* Step 2 - 96-bit bijective mixing using S-box */
    PPK[0] += _S_(PPK[5] ^ Mk16_le((const uint16_t *) &TK[0]));
    PPK[1] += _S_(PPK[0] ^ Mk16_le((const uint16_t *) &TK[2]));
    PPK[2] += _S_(PPK[1] ^ Mk16_le((const uint16_t *) &TK[4]));
    PPK[3] += _S_(PPK[2] ^ Mk16_le((const uint16_t *) &TK[6]));
    PPK[4] += _S_(PPK[3] ^ Mk16_le((const uint16_t *) &TK[8]));
    PPK[5] += _S_(PPK[4] ^ Mk16_le((const uint16_t *) &TK[10]));

    PPK[0] += RotR1(PPK[5] ^ Mk16_le((const uint16_t *) &TK[12]));
    PPK[1] += RotR1(PPK[0] ^ Mk16_le((const uint16_t *) &TK[14]));
    PPK[2] += RotR1(PPK[1]);
    PPK[3] += RotR1(PPK[2]);
    PPK[4] += RotR1(PPK[3]);
    PPK[5] += RotR1(PPK[4]);

    /*
     * Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
     * WEPSeed[0..2] is transmitted as WEP IV
     */
    WEPSeed[0] = Hi8(IV16);
    WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
    WEPSeed[2] = Lo8(IV16);
    WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((const uint16_t *) &TK[0])) >> 1);

#ifdef _BIG_ENDIAN
    int i;
    for (i = 0; i < 6; i++)
        PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
#endif
}

static int
wep_encrypt(uint8_t *key, mblk_t *mp, uint_t off, size_t data_len,
    uint8_t icv[IEEE80211_WEP_CRCLEN])
{
    uint8_t crcbuf[IEEE80211_WEP_CRCLEN];
    uint32_t crc;
    crypto_context_t ctx;
    int rv;

    ctx = NULL;
    rv = rc4_init(&ctx, (const uint8_t *)key, 16);
    if (rv != CRYPTO_SUCCESS)
        return (0);

    /* calculate CRC over unencrypted data */
    CRC32(crc, mp->b_rptr + off, data_len, -1U, crc_table);

    /* encrypt data */
    (void) rc4_crypt(ctx, mp->b_rptr + off, mp->b_rptr + off, data_len);

    /* tack on ICV */
    *(uint32_t *)crcbuf = LE_32(~crc);
    (void) rc4_crypt(ctx, crcbuf, icv, IEEE80211_WEP_CRCLEN);

    (void) rc4_final(ctx, icv, IEEE80211_WEP_CRCLEN);

    return (1);
}

static int
wep_decrypt(uint8_t *key, mblk_t *mp, uint_t off, size_t data_len)
{
    uint8_t crcbuf[IEEE80211_WEP_CRCLEN];
    uint8_t *icv;
    uint32_t crc;
    crypto_context_t ctx;
    int rv;

    ctx = NULL;
    rv = rc4_init(&ctx, (const uint8_t *)key, 16);
    if (rv != CRYPTO_SUCCESS)
        return (0);

    /* decrypt data */
    (void) rc4_crypt(ctx, mp->b_rptr + off, mp->b_rptr + off, data_len);

    /* calculate CRC over unencrypted data */
    CRC32(crc, mp->b_rptr + off, data_len, -1U, crc_table);

    /* decrypt ICV and compare to CRC */
    icv = mp->b_wptr - IEEE80211_WEP_CRCLEN;
    (void) rc4_crypt(ctx, icv, crcbuf, IEEE80211_WEP_CRCLEN);
    (void) rc4_final(ctx, crcbuf, IEEE80211_WEP_CRCLEN);

    return (crc == ~LE_32(*(uint32_t *)crcbuf));
}

static uint32_t
rotl(uint32_t val, int bits)
{
    return ((val << bits) | (val >> (32 - bits)));
}


static uint32_t
rotr(uint32_t val, int bits)
{
    return ((val >> bits) | (val << (32 - bits)));
}


static uint32_t
xswap(uint32_t val)
{
    return (((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8));
}


#define michael_block(l, r) \
do {                \
    r ^= rotl(l, 17);   \
    l += r;         \
    r ^= xswap(l);      \
    l += r;         \
    r ^= rotl(l, 3);    \
    l += r;         \
    r ^= rotr(l, 2);    \
    l += r;         \
    _NOTE(CONSTANTCONDITION)\
} while (0)


static uint32_t
get_le32_split(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3)
{
    return (b0 | (b1 << 8) | (b2 << 16) | (b3 << 24));
}

static uint32_t
get_le32(const uint8_t *p)
{
    return (get_le32_split(p[0], p[1], p[2], p[3]));
}


static void
put_le32(uint8_t *p, uint32_t v)
{
    p[0] = (uint8_t)v;
    p[1] = v >> 8;
    p[2] = v >> 16;
    p[3] = v >> 24;
}

/*
 * Craft pseudo header used to calculate the MIC.
 */
static void
michael_mic_hdr(const struct ieee80211_frame *wh0, uint8_t hdr[16])
{
    const struct ieee80211_frame_addr4 *wh =
        (const struct ieee80211_frame_addr4 *)wh0;

    switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
    case IEEE80211_FC1_DIR_NODS:
        IEEE80211_ADDR_COPY(hdr, wh->i_addr1); /* DA */
        IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr2);
        break;
    case IEEE80211_FC1_DIR_TODS:
        IEEE80211_ADDR_COPY(hdr, wh->i_addr3); /* DA */
        IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr2);
        break;
    case IEEE80211_FC1_DIR_FROMDS:
        IEEE80211_ADDR_COPY(hdr, wh->i_addr1); /* DA */
        IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr3);
        break;
    case IEEE80211_FC1_DIR_DSTODS:
        IEEE80211_ADDR_COPY(hdr, wh->i_addr3); /* DA */
        IEEE80211_ADDR_COPY(hdr + IEEE80211_ADDR_LEN, wh->i_addr4);
        break;
    }

    if (wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_QOS) {
        const struct ieee80211_qosframe *qwh =
            (const struct ieee80211_qosframe *)wh;
        hdr[12] = qwh->i_qos[0] & IEEE80211_QOS_TID;
    } else
        hdr[12] = 0;
    hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
}

/* ARGSUSED */
static void
michael_mic(struct tkip_ctx *ctx, const uint8_t *key,
    mblk_t *mp, uint_t off, size_t data_len,
    uint8_t mic[IEEE80211_WEP_MICLEN])
{
    uint8_t hdr[16];
    uint32_t l, r;
    const uint8_t *data;
    int i, blocks, last;

    michael_mic_hdr((struct ieee80211_frame *)mp->b_rptr, hdr);

    l = get_le32(key);
    r = get_le32(key + 4);

    /* Michael MIC pseudo header: DA, SA, 3 x 0, Priority */
    l ^= get_le32(hdr);
    michael_block(l, r);
    l ^= get_le32(&hdr[4]);
    michael_block(l, r);
    l ^= get_le32(&hdr[8]);
    michael_block(l, r);
    l ^= get_le32(&hdr[12]);
    michael_block(l, r);

    /* first buffer has special handling */
    data = mp->b_rptr + off;

    blocks = data_len / 4;
    last = data_len % 4;

    for (i = 0; i < blocks; i++) {
        l ^= get_le32(&data[4 * i]);
        michael_block(l, r);
    }

    /* Last block and padding (0x5a, 4..7 x 0) */
    switch (last) {
    case 0:
        l ^= 0x5a;
        break;
    case 1:
        l ^= data[4 * i] | 0x5a00;
        break;
    case 2:
        l ^= data[4 * i] | (data[4 * i + 1] << 8) | 0x5a0000;
        break;
    case 3:
        l ^= data[4 * i] | (data[4 * i + 1] << 8) |
            (data[4 * i + 2] << 16) | 0x5a000000;
        break;
    }
    michael_block(l, r);
    /* l ^= 0; */
    michael_block(l, r);

    put_le32(mic, l);
    put_le32(mic + 4, r);
}

static int
tkip_encrypt(struct tkip_ctx *ctx, struct ieee80211_key *key,
    mblk_t *mp, int hdrlen)
{
    struct ieee80211_frame *wh;
    uint8_t *icv;

    wh = (struct ieee80211_frame *)mp->b_rptr;
    if (!ctx->tx_phase1_done) {
        tkip_mixing_phase1(ctx->tx_ttak, key->wk_key, wh->i_addr2,
            (uint32_t)(key->wk_keytsc >> 16));
        ctx->tx_phase1_done = 1;
    }
    tkip_mixing_phase2(ctx->tx_rc4key, key->wk_key, ctx->tx_ttak,
        (uint16_t)key->wk_keytsc);

    icv = mp->b_wptr;
    mp->b_wptr += tkip.ic_trailer;

    (void) wep_encrypt(ctx->tx_rc4key,
        mp, hdrlen + tkip.ic_header,
        MBLKL(mp) -
        (hdrlen + tkip.ic_header + tkip.ic_trailer),
        icv);

    key->wk_keytsc++;
    if ((uint16_t)(key->wk_keytsc) == 0)
        ctx->tx_phase1_done = 0;
    return (1);
}

static int
tkip_decrypt(struct tkip_ctx *ctx, struct ieee80211_key *key,
    mblk_t *mp, int hdrlen)
{
    struct ieee80211_frame *wh;
    uint32_t iv32;
    uint16_t iv16;

    wh = (struct ieee80211_frame *)mp->b_rptr;
    /* tkip_decap already verified header and left seq in rx_rsc */
    iv16 = (uint16_t)ctx->rx_rsc;
    iv32 = (uint32_t)(ctx->rx_rsc >> 16);

    if (iv32 != (uint32_t)(key->wk_keyrsc >> 16) || !ctx->rx_phase1_done) {
        tkip_mixing_phase1(ctx->rx_ttak, key->wk_key,
            wh->i_addr2, iv32);
        ctx->rx_phase1_done = 0;    /* DHCP */
    }
    tkip_mixing_phase2(ctx->rx_rc4key, key->wk_key, ctx->rx_ttak, iv16);

    /* m is unstripped; deduct headers + ICV to get payload */
    if (!wep_decrypt(ctx->rx_rc4key,
        mp, hdrlen + tkip.ic_header,
        MBLKL(mp) -
        (hdrlen + tkip.ic_header + tkip.ic_trailer))) {
        if (iv32 != (uint32_t)(key->wk_keyrsc >> 16)) {
            /*
             * Previously cached Phase1 result was already lost, so
             * it needs to be recalculated for the next packet.
             */
            ctx->rx_phase1_done = 0;
        }
        ieee80211_dbg(IEEE80211_MSG_CRYPTO, "tkip_decrypt() error\n");
        return (0);
    }
    return (1);
}