[deliverable/linux.git] / drivers / net / wireless / rt2x00 / rt2x00crypto.c

/*
	Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
	<http://rt2x00.serialmonkey.com>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the
	Free Software Foundation, Inc.,
	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
	Module: rt2x00lib
	Abstract: rt2x00 crypto specific routines.
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include "rt2x00.h"
#include "rt2x00lib.h"

enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key)
{
	switch (key->alg) {
	case ALG_WEP:
		if (key->keylen == LEN_WEP40)
			return CIPHER_WEP64;
		else
			return CIPHER_WEP128;
	case ALG_TKIP:
		return CIPHER_TKIP;
	case ALG_CCMP:
		return CIPHER_AES;
	default:
		return CIPHER_NONE;
	}
}

unsigned int rt2x00crypto_tx_overhead(struct ieee80211_tx_info *tx_info)
{
	struct ieee80211_key_conf *key = tx_info->control.hw_key;
	unsigned int overhead = 0;

	/*
	 * Extend frame length to include IV/EIV/ICV/MMIC,
	 * note that these lengths should only be added when
	 * mac80211 does not generate it.
	 */
	overhead += key->icv_len;

	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
		overhead += key->iv_len;

	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
		if (key->alg == ALG_TKIP)
			overhead += 8;
	}

	return overhead;
}

void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, unsigned int iv_len)
{
	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);

	if (unlikely(!iv_len))
		return;

	/* Copy IV/EIV data */
	memcpy(skbdesc->iv, skb->data + header_length, iv_len);
}

void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, unsigned int iv_len)
{
	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);

	if (unlikely(!iv_len))
		return;

	/* Copy IV/EIV data */
	memcpy(skbdesc->iv, skb->data + header_length, iv_len);

	/* Move ieee80211 header */
	memmove(skb->data + iv_len, skb->data, header_length);

	/* Pull buffer to correct size */
	skb_pull(skb, iv_len);

	/* IV/EIV data has officially be stripped */
	skbdesc->flags |= FRAME_DESC_IV_STRIPPED;
}

void rt2x00crypto_tx_insert_iv(struct sk_buff *skb)
{
	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
	const unsigned int iv_len =
	    ((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4);

	if (!(skbdesc->flags & FRAME_DESC_IV_STRIPPED))
		return;

	skb_push(skb, iv_len);

	/* Move ieee80211 header */
	memmove(skb->data, skb->data + iv_len, header_length);

	/* Copy IV/EIV data */
	memcpy(skb->data + header_length, skbdesc->iv, iv_len);

	/* IV/EIV data has returned into the frame */
	skbdesc->flags &= ~FRAME_DESC_IV_STRIPPED;
}

void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, unsigned int align,
			       unsigned int header_length,
			       struct rxdone_entry_desc *rxdesc)
{
	unsigned int payload_len = rxdesc->size - header_length;
	unsigned int iv_len;
	unsigned int icv_len;
	unsigned int transfer = 0;

	/*
	 * WEP64/WEP128: Provides IV & ICV
	 * TKIP: Provides IV/EIV & ICV
	 * AES: Provies IV/EIV & ICV
	 */
	switch (rxdesc->cipher) {
	case CIPHER_WEP64:
	case CIPHER_WEP128:
		iv_len = 4;
		icv_len = 4;
		break;
	case CIPHER_TKIP:
		iv_len = 8;
		icv_len = 4;
		break;
	case CIPHER_AES:
		iv_len = 8;
		icv_len = 8;
		break;
	default:
		/* Unsupport type */
		return;
	}

	/*
	 * Make room for new data, note that we increase both
	 * headsize and tailsize when required. The tailsize is
	 * only needed when ICV data needs to be inserted and
	 * the padding is smaller then the ICV data.
	 * When alignment requirements is greater then the
	 * ICV data we must trim the skb to the correct size
	 * because we need to remove the extra bytes.
	 */
	skb_push(skb, iv_len + align);
	if (align < icv_len)
		skb_put(skb, icv_len - align);
	else if (align > icv_len)
		skb_trim(skb, rxdesc->size + iv_len + icv_len);

	/* Move ieee80211 header */
	memmove(skb->data + transfer,
		skb->data + transfer + iv_len + align,
		header_length);
	transfer += header_length;

	/* Copy IV/EIV data */
	memcpy(skb->data + transfer, rxdesc->iv, iv_len);
	transfer += iv_len;

	/* Move payload */
	if (align) {
		memmove(skb->data + transfer,
			skb->data + transfer + align,
			payload_len);
	}

	/*
	 * NOTE: Always count the payload as transfered,
	 * even when alignment was set to zero. This is required
	 * for determining the correct offset for the ICV data.
	 */
	transfer += payload_len;

	/*
	 * Copy ICV data
	 * AES appends 8 bytes, we can't fill the upper
	 * 4 bytes, but mac80211 doesn't care about what
	 * we provide here anyway and strips it immediately.
	 */
	memcpy(skb->data + transfer, &rxdesc->icv, 4);
	transfer += icv_len;

	/* IV/EIV/ICV has been inserted into frame */
	rxdesc->size = transfer;
	rxdesc->flags &= ~RX_FLAG_IV_STRIPPED;
}
Commit	Line	Data
2bb057d0 ID	1	/*
	2	Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
	3	<http://rt2x00.serialmonkey.com>
	4
	5	This program is free software; you can redistribute it and/or modify
	6	it under the terms of the GNU General Public License as published by
	7	the Free Software Foundation; either version 2 of the License, or
	8	(at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program; if not, write to the
	17	Free Software Foundation, Inc.,
	18	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	19	*/
	20
	21	/*
	22	Module: rt2x00lib
	23	Abstract: rt2x00 crypto specific routines.
	24	*/
	25
	26	#include <linux/kernel.h>
	27	#include <linux/module.h>
	28
	29	#include "rt2x00.h"
	30	#include "rt2x00lib.h"
	31
	32	enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key)
	33	{
	34	switch (key->alg) {
	35	case ALG_WEP:
	36	if (key->keylen == LEN_WEP40)
	37	return CIPHER_WEP64;
	38	else
	39	return CIPHER_WEP128;
	40	case ALG_TKIP:
	41	return CIPHER_TKIP;
	42	case ALG_CCMP:
	43	return CIPHER_AES;
	44	default:
	45	return CIPHER_NONE;
	46	}
	47	}
	48
	49	unsigned int rt2x00crypto_tx_overhead(struct ieee80211_tx_info *tx_info)
	50	{
	51	struct ieee80211_key_conf *key = tx_info->control.hw_key;
	52	unsigned int overhead = 0;
	53
	54	/*
	55	* Extend frame length to include IV/EIV/ICV/MMIC,
	56	* note that these lengths should only be added when
	57	* mac80211 does not generate it.
	58	*/
76708dee	59	overhead += key->icv_len;
2bb057d0 ID	60
2bb057d0 ID	61	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
76708dee	62	overhead += key->iv_len;
2bb057d0 ID	63
	64	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
	65	if (key->alg == ALG_TKIP)
	66	overhead += 8;
	67	}
	68
	69	return overhead;
	70	}
	71
dddfb478 ID	72	void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, unsigned int iv_len)
	73	{
	74	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	75	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
	76
	77	if (unlikely(!iv_len))
	78	return;
	79
	80	/* Copy IV/EIV data */
	81	memcpy(skbdesc->iv, skb->data + header_length, iv_len);
	82	}
	83
2bb057d0 ID	84	void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, unsigned int iv_len)
	85	{
	86	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	87	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
	88
	89	if (unlikely(!iv_len))
	90	return;
	91
	92	/* Copy IV/EIV data */
1ce9cdac	93	memcpy(skbdesc->iv, skb->data + header_length, iv_len);
2bb057d0 ID	94
	95	/* Move ieee80211 header */
	96	memmove(skb->data + iv_len, skb->data, header_length);
	97
	98	/* Pull buffer to correct size */
	99	skb_pull(skb, iv_len);
	100
	101	/* IV/EIV data has officially be stripped */
	102	skbdesc->flags \|= FRAME_DESC_IV_STRIPPED;
	103	}
	104
	105	void rt2x00crypto_tx_insert_iv(struct sk_buff *skb)
	106	{
	107	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
	108	unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
	109	const unsigned int iv_len =
1ce9cdac	110	((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4);
2bb057d0 ID	111
	112	if (!(skbdesc->flags & FRAME_DESC_IV_STRIPPED))
	113	return;
	114
	115	skb_push(skb, iv_len);
	116
	117	/* Move ieee80211 header */
	118	memmove(skb->data, skb->data + iv_len, header_length);
	119
	120	/* Copy IV/EIV data */
1ce9cdac	121	memcpy(skb->data + header_length, skbdesc->iv, iv_len);
2bb057d0 ID	122
	123	/* IV/EIV data has returned into the frame */
	124	skbdesc->flags &= ~FRAME_DESC_IV_STRIPPED;
	125	}
	126
	127	void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, unsigned int align,
	128	unsigned int header_length,
	129	struct rxdone_entry_desc *rxdesc)
	130	{
	131	unsigned int payload_len = rxdesc->size - header_length;
	132	unsigned int iv_len;
	133	unsigned int icv_len;
	134	unsigned int transfer = 0;
	135
	136	/*
	137	* WEP64/WEP128: Provides IV & ICV
	138	* TKIP: Provides IV/EIV & ICV
	139	* AES: Provies IV/EIV & ICV
	140	*/
	141	switch (rxdesc->cipher) {
	142	case CIPHER_WEP64:
	143	case CIPHER_WEP128:
	144	iv_len = 4;
	145	icv_len = 4;
	146	break;
	147	case CIPHER_TKIP:
	148	iv_len = 8;
	149	icv_len = 4;
	150	break;
	151	case CIPHER_AES:
	152	iv_len = 8;
	153	icv_len = 8;
	154	break;
	155	default:
	156	/* Unsupport type */
	157	return;
	158	}
	159
	160	/*
	161	* Make room for new data, note that we increase both
	162	* headsize and tailsize when required. The tailsize is
	163	* only needed when ICV data needs to be inserted and
	164	* the padding is smaller then the ICV data.
	165	* When alignment requirements is greater then the
	166	* ICV data we must trim the skb to the correct size
	167	* because we need to remove the extra bytes.
	168	*/
	169	skb_push(skb, iv_len + align);
	170	if (align < icv_len)
	171	skb_put(skb, icv_len - align);
	172	else if (align > icv_len)
	173	skb_trim(skb, rxdesc->size + iv_len + icv_len);
	174
	175	/* Move ieee80211 header */
	176	memmove(skb->data + transfer,
	177	skb->data + transfer + iv_len + align,
	178	header_length);
	179	transfer += header_length;
	180
1ce9cdac ID	181	/* Copy IV/EIV data */
	182	memcpy(skb->data + transfer, rxdesc->iv, iv_len);
	183	transfer += iv_len;
2bb057d0 ID	184
	185	/* Move payload */
	186	if (align) {
	187	memmove(skb->data + transfer,
	188	skb->data + transfer + align,
	189	payload_len);
	190	}
	191
	192	/*
	193	* NOTE: Always count the payload as transfered,
	194	* even when alignment was set to zero. This is required
	195	* for determining the correct offset for the ICV data.
	196	*/
	197	transfer += payload_len;
	198
1ce9cdac ID	199	/*
	200	* Copy ICV data
	201	* AES appends 8 bytes, we can't fill the upper
	202	* 4 bytes, but mac80211 doesn't care about what
	203	* we provide here anyway and strips it immediately.
	204	*/
	205	memcpy(skb->data + transfer, &rxdesc->icv, 4);
	206	transfer += icv_len;
2bb057d0 ID	207
	208	/* IV/EIV/ICV has been inserted into frame */
	209	rxdesc->size = transfer;
	210	rxdesc->flags &= ~RX_FLAG_IV_STRIPPED;
	211	}