/*

   * lib80211 crypt: host-based TKIP encryption implementation for lib80211

   *

   * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>

   * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com>

   *
   * 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.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/err.h>

  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/random.h>

  #include <linux/scatterlist.h>

  #include <linux/skbuff.h>
  #include <linux/netdevice.h>

  #include <linux/mm.h>

  #include <linux/if_ether.h>
  #include <linux/if_arp.h>
  #include <asm/string.h>

  #include <linux/wireless.h>
  #include <linux/ieee80211.h>
  #include <net/iw_handler.h>

  #include <linux/crypto.h>

  #include <linux/crc32.h>

  #include <net/lib80211.h>

  MODULE_AUTHOR("Jouni Malinen");

  MODULE_DESCRIPTION("lib80211 crypt: TKIP");

  MODULE_LICENSE("GPL");

  #define TKIP_HDR_LEN 8

  struct lib80211_tkip_data {

  #define TKIP_KEY_LEN 32
  	u8 key[TKIP_KEY_LEN];
  	int key_set;
  
  	u32 tx_iv32;
  	u16 tx_iv16;
  	u16 tx_ttak[5];
  	int tx_phase1_done;
  
  	u32 rx_iv32;
  	u16 rx_iv16;
  	u16 rx_ttak[5];
  	int rx_phase1_done;
  	u32 rx_iv32_new;
  	u16 rx_iv16_new;
  
  	u32 dot11RSNAStatsTKIPReplays;
  	u32 dot11RSNAStatsTKIPICVErrors;
  	u32 dot11RSNAStatsTKIPLocalMICFailures;
  
  	int key_idx;

  	struct crypto_blkcipher *rx_tfm_arc4;
  	struct crypto_hash *rx_tfm_michael;
  	struct crypto_blkcipher *tx_tfm_arc4;
  	struct crypto_hash *tx_tfm_michael;

  
  	/* scratch buffers for virt_to_page() (crypto API) */
  	u8 rx_hdr[16], tx_hdr[16];

  	unsigned long flags;

  };

  static unsigned long lib80211_tkip_set_flags(unsigned long flags, void *priv)

  {

  	struct lib80211_tkip_data *_priv = priv;

  	unsigned long old_flags = _priv->flags;
  	_priv->flags = flags;
  	return old_flags;
  }

  static unsigned long lib80211_tkip_get_flags(void *priv)

  {

  	struct lib80211_tkip_data *_priv = priv;

  	return _priv->flags;
  }

  static void *lib80211_tkip_init(int key_idx)

  {

  	struct lib80211_tkip_data *priv;

  	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);

  	if (priv == NULL)
  		goto fail;

  	priv->key_idx = key_idx;

  	priv->tx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,

  						CRYPTO_ALG_ASYNC);

  	if (IS_ERR(priv->tx_tfm_arc4)) {

  		priv->tx_tfm_arc4 = NULL;

  		goto fail;
  	}

  	priv->tx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
  						 CRYPTO_ALG_ASYNC);
  	if (IS_ERR(priv->tx_tfm_michael)) {

  		priv->tx_tfm_michael = NULL;

  		goto fail;
  	}

  	priv->rx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
  						CRYPTO_ALG_ASYNC);
  	if (IS_ERR(priv->rx_tfm_arc4)) {

  		priv->rx_tfm_arc4 = NULL;

  		goto fail;
  	}

  	priv->rx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
  						 CRYPTO_ALG_ASYNC);
  	if (IS_ERR(priv->rx_tfm_michael)) {

  		priv->rx_tfm_michael = NULL;

  		goto fail;
  	}
  
  	return priv;

        fail:

  	if (priv) {

  		if (priv->tx_tfm_michael)

  			crypto_free_hash(priv->tx_tfm_michael);

  		if (priv->tx_tfm_arc4)

  			crypto_free_blkcipher(priv->tx_tfm_arc4);

  		if (priv->rx_tfm_michael)

  			crypto_free_hash(priv->rx_tfm_michael);

  		if (priv->rx_tfm_arc4)

  			crypto_free_blkcipher(priv->rx_tfm_arc4);

  		kfree(priv);
  	}
  
  	return NULL;
  }

  static void lib80211_tkip_deinit(void *priv)

  {

  	struct lib80211_tkip_data *_priv = priv;

  	if (_priv) {
  		if (_priv->tx_tfm_michael)

  			crypto_free_hash(_priv->tx_tfm_michael);

  		if (_priv->tx_tfm_arc4)

  			crypto_free_blkcipher(_priv->tx_tfm_arc4);

  		if (_priv->rx_tfm_michael)

  			crypto_free_hash(_priv->rx_tfm_michael);

  		if (_priv->rx_tfm_arc4)

  			crypto_free_blkcipher(_priv->rx_tfm_arc4);

  	}

  	kfree(priv);
  }

  static inline u16 RotR1(u16 val)
  {
  	return (val >> 1) | (val << 15);
  }

  static inline u8 Lo8(u16 val)
  {
  	return val & 0xff;
  }

  static inline u8 Hi8(u16 val)
  {
  	return val >> 8;
  }

  static inline u16 Lo16(u32 val)
  {
  	return val & 0xffff;
  }

  static inline u16 Hi16(u32 val)
  {
  	return val >> 16;
  }

  static inline u16 Mk16(u8 hi, u8 lo)
  {
  	return lo | (((u16) hi) << 8);
  }

  static inline u16 Mk16_le(__le16 * v)

  {
  	return le16_to_cpu(*v);
  }

  static const u16 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 inline u16 _S_(u16 v)
  {
  	u16 t = Sbox[Hi8(v)];
  	return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
  }

  #define PHASE1_LOOP_COUNT 8

  static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
  			       u32 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(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,

  			       u16 IV16)
  {
  	/* Make temporary area overlap WEP seed so that the final copy can be
  	 * avoided on little endian hosts. */

  	u16 *PPK = (u16 *) & 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((__le16 *) & TK[0]));
  	PPK[1] += _S_(PPK[0] ^ Mk16_le((__le16 *) & TK[2]));
  	PPK[2] += _S_(PPK[1] ^ Mk16_le((__le16 *) & TK[4]));
  	PPK[3] += _S_(PPK[2] ^ Mk16_le((__le16 *) & TK[6]));
  	PPK[4] += _S_(PPK[3] ^ Mk16_le((__le16 *) & TK[8]));
  	PPK[5] += _S_(PPK[4] ^ Mk16_le((__le16 *) & TK[10]));
  
  	PPK[0] += RotR1(PPK[5] ^ Mk16_le((__le16 *) & TK[12]));
  	PPK[1] += RotR1(PPK[0] ^ Mk16_le((__le16 *) & 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((__le16 *) & 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 lib80211_tkip_hdr(struct sk_buff *skb, int hdr_len,

  			      u8 * rc4key, int keylen, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	u8 *pos;

  	struct ieee80211_hdr *hdr;

  	hdr = (struct ieee80211_hdr *)skb->data;

  	if (skb_headroom(skb) < TKIP_HDR_LEN || skb->len < hdr_len)

  		return -1;
  
  	if (rc4key == NULL || keylen < 16)
  		return -1;

  	if (!tkey->tx_phase1_done) {
  		tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
  				   tkey->tx_iv32);
  		tkey->tx_phase1_done = 1;
  	}
  	tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);

  	pos = skb_push(skb, TKIP_HDR_LEN);
  	memmove(pos, pos + TKIP_HDR_LEN, hdr_len);

  	pos += hdr_len;

  	*pos++ = *rc4key;
  	*pos++ = *(rc4key + 1);
  	*pos++ = *(rc4key + 2);

  	*pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;

  	*pos++ = tkey->tx_iv32 & 0xff;
  	*pos++ = (tkey->tx_iv32 >> 8) & 0xff;
  	*pos++ = (tkey->tx_iv32 >> 16) & 0xff;
  	*pos++ = (tkey->tx_iv32 >> 24) & 0xff;

  	tkey->tx_iv16++;
  	if (tkey->tx_iv16 == 0) {
  		tkey->tx_phase1_done = 0;
  		tkey->tx_iv32++;
  	}

  	return TKIP_HDR_LEN;

  }

  static int lib80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	struct blkcipher_desc desc = { .tfm = tkey->tx_tfm_arc4 };

  	int len;

  	u8 rc4key[16], *pos, *icv;
  	u32 crc;

  	struct scatterlist sg;

  	if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {

  		if (net_ratelimit()) {

  			struct ieee80211_hdr *hdr =
  			    (struct ieee80211_hdr *)skb->data;

  			printk(KERN_DEBUG ": TKIP countermeasures: dropped "

  			       "TX packet to %pM
  ", hdr->addr1);

  		}
  		return -1;
  	}
  
  	if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
  		return -1;
  
  	len = skb->len - hdr_len;
  	pos = skb->data + hdr_len;

  	if ((lib80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)

  		return -1;

  	crc = ~crc32_le(~0, pos, len);

  	icv = skb_put(skb, 4);

  	icv[0] = crc;
  	icv[1] = crc >> 8;
  	icv[2] = crc >> 16;
  	icv[3] = crc >> 24;

  	crypto_blkcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);

  	sg_init_one(&sg, pos, len + 4);

  	return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);

  }

  /*
   * deal with seq counter wrapping correctly.
   * refer to timer_after() for jiffies wrapping handling
   */
  static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
  				    u32 iv32_o, u16 iv16_o)
  {
  	if ((s32)iv32_n - (s32)iv32_o < 0 ||
  	    (iv32_n == iv32_o && iv16_n <= iv16_o))
  		return 1;
  	return 0;
  }

  static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	struct blkcipher_desc desc = { .tfm = tkey->rx_tfm_arc4 };

  	u8 rc4key[16];
  	u8 keyidx, *pos;
  	u32 iv32;
  	u16 iv16;

  	struct ieee80211_hdr *hdr;

  	u8 icv[4];
  	u32 crc;
  	struct scatterlist sg;
  	int plen;

  	hdr = (struct ieee80211_hdr *)skb->data;

  	if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {

  		if (net_ratelimit()) {

  			printk(KERN_DEBUG ": TKIP countermeasures: dropped "

  			       "received packet from %pM
  ", hdr->addr2);

  		}
  		return -1;
  	}

  	if (skb->len < hdr_len + TKIP_HDR_LEN + 4)

  		return -1;

  	pos = skb->data + hdr_len;
  	keyidx = pos[3];
  	if (!(keyidx & (1 << 5))) {
  		if (net_ratelimit()) {
  			printk(KERN_DEBUG "TKIP: received packet without ExtIV"

  			       " flag from %pM
  ", hdr->addr2);

  		}
  		return -2;
  	}
  	keyidx >>= 6;
  	if (tkey->key_idx != keyidx) {
  		printk(KERN_DEBUG "TKIP: RX tkey->key_idx=%d frame "
  		       "keyidx=%d priv=%p
  ", tkey->key_idx, keyidx, priv);
  		return -6;
  	}
  	if (!tkey->key_set) {
  		if (net_ratelimit()) {

  			printk(KERN_DEBUG "TKIP: received packet from %pM"

  			       " with keyid=%d that does not have a configured"

  			       " key
  ", hdr->addr2, keyidx);

  		}
  		return -3;
  	}
  	iv16 = (pos[0] << 8) | pos[2];
  	iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);

  	pos += TKIP_HDR_LEN;

  	if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {

  #ifdef CONFIG_LIB80211_DEBUG

  		if (net_ratelimit()) {
  			printk(KERN_DEBUG "TKIP: replay detected: STA=%pM"

  			       " previous TSC %08x%04x received TSC "

  			       "%08x%04x
  ", hdr->addr2,

  			       tkey->rx_iv32, tkey->rx_iv16, iv32, iv16);
  		}

  #endif

  		tkey->dot11RSNAStatsTKIPReplays++;
  		return -4;
  	}
  
  	if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
  		tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
  		tkey->rx_phase1_done = 1;
  	}
  	tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
  
  	plen = skb->len - hdr_len - 12;

  	crypto_blkcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);

  	sg_init_one(&sg, pos, plen + 4);

  	if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) {
  		if (net_ratelimit()) {
  			printk(KERN_DEBUG ": TKIP: failed to decrypt "

  			       "received packet from %pM
  ",
  			       hdr->addr2);

  		}
  		return -7;
  	}

  
  	crc = ~crc32_le(~0, pos, plen);
  	icv[0] = crc;
  	icv[1] = crc >> 8;
  	icv[2] = crc >> 16;
  	icv[3] = crc >> 24;
  	if (memcmp(icv, pos + plen, 4) != 0) {
  		if (iv32 != tkey->rx_iv32) {
  			/* Previously cached Phase1 result was already lost, so
  			 * it needs to be recalculated for the next packet. */
  			tkey->rx_phase1_done = 0;
  		}

  #ifdef CONFIG_LIB80211_DEBUG

  		if (net_ratelimit()) {
  			printk(KERN_DEBUG "TKIP: ICV error detected: STA="

  			       "%pM
  ", hdr->addr2);

  		}

  #endif

  		tkey->dot11RSNAStatsTKIPICVErrors++;
  		return -5;
  	}
  
  	/* Update real counters only after Michael MIC verification has
  	 * completed */
  	tkey->rx_iv32_new = iv32;
  	tkey->rx_iv16_new = iv16;
  
  	/* Remove IV and ICV */

  	memmove(skb->data + TKIP_HDR_LEN, skb->data, hdr_len);
  	skb_pull(skb, TKIP_HDR_LEN);

  	skb_trim(skb, skb->len - 4);
  
  	return keyidx;
  }

  static int michael_mic(struct crypto_hash *tfm_michael, u8 * key, u8 * hdr,

  		       u8 * data, size_t data_len, u8 * mic)

  {

  	struct hash_desc desc;

  	struct scatterlist sg[2];

  	if (tfm_michael == NULL) {

  		pr_warn("%s(): tfm_michael == NULL
  ", __func__);

  		return -1;
  	}

  	sg_init_table(sg, 2);

  	sg_set_buf(&sg[0], hdr, 16);
  	sg_set_buf(&sg[1], data, data_len);

  	if (crypto_hash_setkey(tfm_michael, key, 8))

  		return -1;

  	desc.tfm = tfm_michael;

  	desc.flags = 0;
  	return crypto_hash_digest(&desc, sg, data_len + 16, mic);

  }

  static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)

  {

  	struct ieee80211_hdr *hdr11;

  	hdr11 = (struct ieee80211_hdr *)skb->data;

  	switch (le16_to_cpu(hdr11->frame_control) &

  		(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
  	case IEEE80211_FCTL_TODS:

  		memcpy(hdr, hdr11->addr3, ETH_ALEN);	/* DA */
  		memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN);	/* SA */

  		break;
  	case IEEE80211_FCTL_FROMDS:

  		memcpy(hdr, hdr11->addr1, ETH_ALEN);	/* DA */
  		memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN);	/* SA */

  		break;
  	case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:

  		memcpy(hdr, hdr11->addr3, ETH_ALEN);	/* DA */
  		memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN);	/* SA */

  		break;
  	case 0:

  		memcpy(hdr, hdr11->addr1, ETH_ALEN);	/* DA */
  		memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN);	/* SA */

  		break;
  	}

  	if (ieee80211_is_data_qos(hdr11->frame_control)) {

  		hdr[12] = le16_to_cpu(*((__le16 *)ieee80211_get_qos_ctl(hdr11)))

  			& IEEE80211_QOS_CTL_TID_MASK;

  	} else
  		hdr[12] = 0;		/* priority */

  	hdr[13] = hdr[14] = hdr[15] = 0;	/* reserved */

  }

  static int lib80211_michael_mic_add(struct sk_buff *skb, int hdr_len,

  				     void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	u8 *pos;
  
  	if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
  		printk(KERN_DEBUG "Invalid packet for Michael MIC add "
  		       "(tailroom=%d hdr_len=%d skb->len=%d)
  ",
  		       skb_tailroom(skb), hdr_len, skb->len);
  		return -1;
  	}
  
  	michael_mic_hdr(skb, tkey->tx_hdr);
  	pos = skb_put(skb, 8);

  	if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,

  			skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
  		return -1;
  
  	return 0;
  }

  static void lib80211_michael_mic_failure(struct net_device *dev,
  					  struct ieee80211_hdr *hdr,

  					  int keyidx)

  {
  	union iwreq_data wrqu;
  	struct iw_michaelmicfailure ev;
  
  	/* TODO: needed parameters: count, keyid, key type, TSC */
  	memset(&ev, 0, sizeof(ev));
  	ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
  	if (hdr->addr1[0] & 0x01)
  		ev.flags |= IW_MICFAILURE_GROUP;
  	else
  		ev.flags |= IW_MICFAILURE_PAIRWISE;
  	ev.src_addr.sa_family = ARPHRD_ETHER;
  	memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
  	memset(&wrqu, 0, sizeof(wrqu));
  	wrqu.data.length = sizeof(ev);

  	wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);

  }

  static int lib80211_michael_mic_verify(struct sk_buff *skb, int keyidx,

  					int hdr_len, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	u8 mic[8];
  
  	if (!tkey->key_set)
  		return -1;
  
  	michael_mic_hdr(skb, tkey->rx_hdr);

  	if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,

  			skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
  		return -1;
  	if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {

  		struct ieee80211_hdr *hdr;
  		hdr = (struct ieee80211_hdr *)skb->data;

  		printk(KERN_DEBUG "%s: Michael MIC verification failed for "

  		       "MSDU from %pM keyidx=%d
  ",
  		       skb->dev ? skb->dev->name : "N/A", hdr->addr2,

  		       keyidx);
  		if (skb->dev)

  			lib80211_michael_mic_failure(skb->dev, hdr, keyidx);

  		tkey->dot11RSNAStatsTKIPLocalMICFailures++;
  		return -1;
  	}
  
  	/* Update TSC counters for RX now that the packet verification has
  	 * completed. */
  	tkey->rx_iv32 = tkey->rx_iv32_new;
  	tkey->rx_iv16 = tkey->rx_iv16_new;
  
  	skb_trim(skb, skb->len - 8);
  
  	return 0;
  }

  static int lib80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  	int keyidx;

  	struct crypto_hash *tfm = tkey->tx_tfm_michael;
  	struct crypto_blkcipher *tfm2 = tkey->tx_tfm_arc4;
  	struct crypto_hash *tfm3 = tkey->rx_tfm_michael;
  	struct crypto_blkcipher *tfm4 = tkey->rx_tfm_arc4;

  
  	keyidx = tkey->key_idx;
  	memset(tkey, 0, sizeof(*tkey));
  	tkey->key_idx = keyidx;

  	tkey->tx_tfm_michael = tfm;
  	tkey->tx_tfm_arc4 = tfm2;
  	tkey->rx_tfm_michael = tfm3;
  	tkey->rx_tfm_arc4 = tfm4;

  	if (len == TKIP_KEY_LEN) {
  		memcpy(tkey->key, key, TKIP_KEY_LEN);
  		tkey->key_set = 1;

  		tkey->tx_iv16 = 1;	/* TSC is initialized to 1 */

  		if (seq) {
  			tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |

  			    (seq[3] << 8) | seq[2];

  			tkey->rx_iv16 = (seq[1] << 8) | seq[0];
  		}
  	} else if (len == 0)
  		tkey->key_set = 0;
  	else
  		return -1;
  
  	return 0;
  }

  static int lib80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)

  {

  	struct lib80211_tkip_data *tkey = priv;

  
  	if (len < TKIP_KEY_LEN)
  		return -1;
  
  	if (!tkey->key_set)
  		return 0;
  	memcpy(key, tkey->key, TKIP_KEY_LEN);
  
  	if (seq) {
  		/* Return the sequence number of the last transmitted frame. */
  		u16 iv16 = tkey->tx_iv16;
  		u32 iv32 = tkey->tx_iv32;
  		if (iv16 == 0)
  			iv32--;
  		iv16--;
  		seq[0] = tkey->tx_iv16;
  		seq[1] = tkey->tx_iv16 >> 8;
  		seq[2] = tkey->tx_iv32;
  		seq[3] = tkey->tx_iv32 >> 8;
  		seq[4] = tkey->tx_iv32 >> 16;
  		seq[5] = tkey->tx_iv32 >> 24;
  	}
  
  	return TKIP_KEY_LEN;
  }

  static char *lib80211_tkip_print_stats(char *p, void *priv)

  {

  	struct lib80211_tkip_data *tkip = priv;

  	p += sprintf(p, "key[%d] alg=TKIP key_set=%d "
  		     "tx_pn=%02x%02x%02x%02x%02x%02x "
  		     "rx_pn=%02x%02x%02x%02x%02x%02x "
  		     "replays=%d icv_errors=%d local_mic_failures=%d
  ",
  		     tkip->key_idx, tkip->key_set,
  		     (tkip->tx_iv32 >> 24) & 0xff,
  		     (tkip->tx_iv32 >> 16) & 0xff,
  		     (tkip->tx_iv32 >> 8) & 0xff,
  		     tkip->tx_iv32 & 0xff,
  		     (tkip->tx_iv16 >> 8) & 0xff,
  		     tkip->tx_iv16 & 0xff,
  		     (tkip->rx_iv32 >> 24) & 0xff,
  		     (tkip->rx_iv32 >> 16) & 0xff,
  		     (tkip->rx_iv32 >> 8) & 0xff,
  		     tkip->rx_iv32 & 0xff,
  		     (tkip->rx_iv16 >> 8) & 0xff,
  		     tkip->rx_iv16 & 0xff,
  		     tkip->dot11RSNAStatsTKIPReplays,
  		     tkip->dot11RSNAStatsTKIPICVErrors,
  		     tkip->dot11RSNAStatsTKIPLocalMICFailures);
  	return p;
  }

  static struct lib80211_crypto_ops lib80211_crypt_tkip = {

  	.name = "TKIP",

  	.init = lib80211_tkip_init,
  	.deinit = lib80211_tkip_deinit,

  	.encrypt_mpdu = lib80211_tkip_encrypt,
  	.decrypt_mpdu = lib80211_tkip_decrypt,
  	.encrypt_msdu = lib80211_michael_mic_add,
  	.decrypt_msdu = lib80211_michael_mic_verify,
  	.set_key = lib80211_tkip_set_key,
  	.get_key = lib80211_tkip_get_key,
  	.print_stats = lib80211_tkip_print_stats,

  	.extra_mpdu_prefix_len = 4 + 4,	/* IV + ExtIV */
  	.extra_mpdu_postfix_len = 4,	/* ICV */
  	.extra_msdu_postfix_len = 8,	/* MIC */

  	.get_flags = lib80211_tkip_get_flags,
  	.set_flags = lib80211_tkip_set_flags,

  	.owner = THIS_MODULE,

  };

  static int __init lib80211_crypto_tkip_init(void)

  {

  	return lib80211_register_crypto_ops(&lib80211_crypt_tkip);

  }

  static void __exit lib80211_crypto_tkip_exit(void)

  {

  	lib80211_unregister_crypto_ops(&lib80211_crypt_tkip);

  }

  module_init(lib80211_crypto_tkip_init);
  module_exit(lib80211_crypto_tkip_exit);