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rt2x00: Implement HW encryption (rt61pci)
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rt61pci supports hardware encryption.
rt61pci supports up to 4 shared keys and up to 64 pairwise keys.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Ivo van Doorn authored and John W. Linville committed Aug 22, 2008
1 parent 2bb057d commit 61e754f
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Showing 3 changed files with 270 additions and 8 deletions.
1 change: 1 addition & 0 deletions drivers/net/wireless/rt2x00/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -107,6 +107,7 @@ config RT61PCI
depends on PCI
select RT2X00_LIB_PCI
select RT2X00_LIB_FIRMWARE
select RT2X00_LIB_CRYPTO
select CRC_ITU_T
select EEPROM_93CX6
---help---
Expand Down
256 changes: 250 additions & 6 deletions drivers/net/wireless/rt2x00/rt61pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -346,6 +346,204 @@ static void rt61pci_init_led(struct rt2x00_dev *rt2x00dev,
/*
* Configuration handlers.
*/
static int rt61pci_config_shared_key(struct rt2x00_dev *rt2x00dev,
struct rt2x00lib_crypto *crypto,
struct ieee80211_key_conf *key)
{
struct hw_key_entry key_entry;
struct rt2x00_field32 field;
u32 mask;
u32 reg;

if (crypto->cmd == SET_KEY) {
/*
* rt2x00lib can't determine the correct free
* key_idx for shared keys. We have 1 register
* with key valid bits. The goal is simple, read
* the register, if that is full we have no slots
* left.
* Note that each BSS is allowed to have up to 4
* shared keys, so put a mask over the allowed
* entries.
*/
mask = (0xf << crypto->bssidx);

rt2x00pci_register_read(rt2x00dev, SEC_CSR0, &reg);
reg &= mask;

if (reg && reg == mask)
return -ENOSPC;

key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;

/*
* Upload key to hardware
*/
memcpy(key_entry.key, crypto->key,
sizeof(key_entry.key));
memcpy(key_entry.tx_mic, crypto->tx_mic,
sizeof(key_entry.tx_mic));
memcpy(key_entry.rx_mic, crypto->rx_mic,
sizeof(key_entry.rx_mic));

reg = SHARED_KEY_ENTRY(key->hw_key_idx);
rt2x00pci_register_multiwrite(rt2x00dev, reg,
&key_entry, sizeof(key_entry));

/*
* The cipher types are stored over 2 registers.
* bssidx 0 and 1 keys are stored in SEC_CSR1 and
* bssidx 1 and 2 keys are stored in SEC_CSR5.
* Using the correct defines correctly will cause overhead,
* so just calculate the correct offset.
*/
if (key->hw_key_idx < 8) {
field.bit_offset = (3 * key->hw_key_idx);
field.bit_mask = 0x7 << field.bit_offset;

rt2x00pci_register_read(rt2x00dev, SEC_CSR1, &reg);
rt2x00_set_field32(&reg, field, crypto->cipher);
rt2x00pci_register_write(rt2x00dev, SEC_CSR1, reg);
} else {
field.bit_offset = (3 * (key->hw_key_idx - 8));
field.bit_mask = 0x7 << field.bit_offset;

rt2x00pci_register_read(rt2x00dev, SEC_CSR5, &reg);
rt2x00_set_field32(&reg, field, crypto->cipher);
rt2x00pci_register_write(rt2x00dev, SEC_CSR5, reg);
}

/*
* The driver does not support the IV/EIV generation
* in hardware. However it doesn't support the IV/EIV
* inside the ieee80211 frame either, but requires it
* to be provided seperately for the descriptor.
* rt2x00lib will cut the IV/EIV data out of all frames
* given to us by mac80211, but we must tell mac80211
* to generate the IV/EIV data.
*/
key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
}

/*
* SEC_CSR0 contains only single-bit fields to indicate
* a particular key is valid. Because using the FIELD32()
* defines directly will cause a lot of overhead we use
* a calculation to determine the correct bit directly.
*/
mask = 1 << key->hw_key_idx;

rt2x00pci_register_read(rt2x00dev, SEC_CSR0, &reg);
if (crypto->cmd == SET_KEY)
reg |= mask;
else if (crypto->cmd == DISABLE_KEY)
reg &= ~mask;
rt2x00pci_register_write(rt2x00dev, SEC_CSR0, reg);

return 0;
}

static int rt61pci_config_pairwise_key(struct rt2x00_dev *rt2x00dev,
struct rt2x00lib_crypto *crypto,
struct ieee80211_key_conf *key)
{
struct hw_pairwise_ta_entry addr_entry;
struct hw_key_entry key_entry;
u32 mask;
u32 reg;

if (crypto->cmd == SET_KEY) {
/*
* rt2x00lib can't determine the correct free
* key_idx for pairwise keys. We have 2 registers
* with key valid bits. The goal is simple, read
* the first register, if that is full move to
* the next register.
* When both registers are full, we drop the key,
* otherwise we use the first invalid entry.
*/
rt2x00pci_register_read(rt2x00dev, SEC_CSR2, &reg);
if (reg && reg == ~0) {
key->hw_key_idx = 32;
rt2x00pci_register_read(rt2x00dev, SEC_CSR3, &reg);
if (reg && reg == ~0)
return -ENOSPC;
}

key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;

/*
* Upload key to hardware
*/
memcpy(key_entry.key, crypto->key,
sizeof(key_entry.key));
memcpy(key_entry.tx_mic, crypto->tx_mic,
sizeof(key_entry.tx_mic));
memcpy(key_entry.rx_mic, crypto->rx_mic,
sizeof(key_entry.rx_mic));

memset(&addr_entry, 0, sizeof(addr_entry));
memcpy(&addr_entry, crypto->address, ETH_ALEN);
addr_entry.cipher = crypto->cipher;

reg = PAIRWISE_KEY_ENTRY(key->hw_key_idx);
rt2x00pci_register_multiwrite(rt2x00dev, reg,
&key_entry, sizeof(key_entry));

reg = PAIRWISE_TA_ENTRY(key->hw_key_idx);
rt2x00pci_register_multiwrite(rt2x00dev, reg,
&addr_entry, sizeof(addr_entry));

/*
* Enable pairwise lookup table for given BSS idx,
* without this received frames will not be decrypted
* by the hardware.
*/
rt2x00pci_register_read(rt2x00dev, SEC_CSR4, &reg);
reg |= (1 << crypto->bssidx);
rt2x00pci_register_write(rt2x00dev, SEC_CSR4, reg);

/*
* The driver does not support the IV/EIV generation
* in hardware. However it doesn't support the IV/EIV
* inside the ieee80211 frame either, but requires it
* to be provided seperately for the descriptor.
* rt2x00lib will cut the IV/EIV data out of all frames
* given to us by mac80211, but we must tell mac80211
* to generate the IV/EIV data.
*/
key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
}

/*
* SEC_CSR2 and SEC_CSR3 contain only single-bit fields to indicate
* a particular key is valid. Because using the FIELD32()
* defines directly will cause a lot of overhead we use
* a calculation to determine the correct bit directly.
*/
if (key->hw_key_idx < 32) {
mask = 1 << key->hw_key_idx;

rt2x00pci_register_read(rt2x00dev, SEC_CSR2, &reg);
if (crypto->cmd == SET_KEY)
reg |= mask;
else if (crypto->cmd == DISABLE_KEY)
reg &= ~mask;
rt2x00pci_register_write(rt2x00dev, SEC_CSR2, reg);
} else {
mask = 1 << (key->hw_key_idx - 32);

rt2x00pci_register_read(rt2x00dev, SEC_CSR3, &reg);
if (crypto->cmd == SET_KEY)
reg |= mask;
else if (crypto->cmd == DISABLE_KEY)
reg &= ~mask;
rt2x00pci_register_write(rt2x00dev, SEC_CSR3, reg);
}

return 0;
}

static void rt61pci_config_filter(struct rt2x00_dev *rt2x00dev,
const unsigned int filter_flags)
{
Expand Down Expand Up @@ -1533,8 +1731,8 @@ static int rt61pci_set_device_state(struct rt2x00_dev *rt2x00dev,
* TX descriptor initialization
*/
static void rt61pci_write_tx_desc(struct rt2x00_dev *rt2x00dev,
struct sk_buff *skb,
struct txentry_desc *txdesc)
struct sk_buff *skb,
struct txentry_desc *txdesc)
{
struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
__le32 *txd = skbdesc->desc;
Expand All @@ -1548,7 +1746,7 @@ static void rt61pci_write_tx_desc(struct rt2x00_dev *rt2x00dev,
rt2x00_set_field32(&word, TXD_W1_AIFSN, txdesc->aifs);
rt2x00_set_field32(&word, TXD_W1_CWMIN, txdesc->cw_min);
rt2x00_set_field32(&word, TXD_W1_CWMAX, txdesc->cw_max);
rt2x00_set_field32(&word, TXD_W1_IV_OFFSET, IEEE80211_HEADER);
rt2x00_set_field32(&word, TXD_W1_IV_OFFSET, txdesc->iv_offset);
rt2x00_set_field32(&word, TXD_W1_HW_SEQUENCE,
test_bit(ENTRY_TXD_GENERATE_SEQ, &txdesc->flags));
rt2x00_set_field32(&word, TXD_W1_BUFFER_COUNT, 1);
Expand All @@ -1561,6 +1759,11 @@ static void rt61pci_write_tx_desc(struct rt2x00_dev *rt2x00dev,
rt2x00_set_field32(&word, TXD_W2_PLCP_LENGTH_HIGH, txdesc->length_high);
rt2x00_desc_write(txd, 2, word);

if (test_bit(ENTRY_TXD_ENCRYPT, &txdesc->flags)) {
_rt2x00_desc_write(txd, 3, skbdesc->iv);
_rt2x00_desc_write(txd, 4, skbdesc->eiv);
}

rt2x00_desc_read(txd, 5, &word);
rt2x00_set_field32(&word, TXD_W5_PID_TYPE, skbdesc->entry->queue->qid);
rt2x00_set_field32(&word, TXD_W5_PID_SUBTYPE,
Expand Down Expand Up @@ -1595,11 +1798,15 @@ static void rt61pci_write_tx_desc(struct rt2x00_dev *rt2x00dev,
rt2x00_set_field32(&word, TXD_W0_IFS, txdesc->ifs);
rt2x00_set_field32(&word, TXD_W0_RETRY_MODE,
test_bit(ENTRY_TXD_RETRY_MODE, &txdesc->flags));
rt2x00_set_field32(&word, TXD_W0_TKIP_MIC, 0);
rt2x00_set_field32(&word, TXD_W0_TKIP_MIC,
test_bit(ENTRY_TXD_ENCRYPT_MMIC, &txdesc->flags));
rt2x00_set_field32(&word, TXD_W0_KEY_TABLE,
test_bit(ENTRY_TXD_ENCRYPT_PAIRWISE, &txdesc->flags));
rt2x00_set_field32(&word, TXD_W0_KEY_INDEX, txdesc->key_idx);
rt2x00_set_field32(&word, TXD_W0_DATABYTE_COUNT, skb->len);
rt2x00_set_field32(&word, TXD_W0_BURST,
test_bit(ENTRY_TXD_BURST, &txdesc->flags));
rt2x00_set_field32(&word, TXD_W0_CIPHER_ALG, CIPHER_NONE);
rt2x00_set_field32(&word, TXD_W0_CIPHER_ALG, txdesc->cipher);
rt2x00_desc_write(txd, 0, word);
}

Expand Down Expand Up @@ -1718,6 +1925,7 @@ static int rt61pci_agc_to_rssi(struct rt2x00_dev *rt2x00dev, int rxd_w1)
static void rt61pci_fill_rxdone(struct queue_entry *entry,
struct rxdone_entry_desc *rxdesc)
{
struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
struct queue_entry_priv_pci *entry_priv = entry->priv_data;
u32 word0;
u32 word1;
Expand All @@ -1728,14 +1936,46 @@ static void rt61pci_fill_rxdone(struct queue_entry *entry,
if (rt2x00_get_field32(word0, RXD_W0_CRC_ERROR))
rxdesc->flags |= RX_FLAG_FAILED_FCS_CRC;

if (test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags)) {
rxdesc->cipher =
rt2x00_get_field32(word0, RXD_W0_CIPHER_ALG);
rxdesc->cipher_status =
rt2x00_get_field32(word0, RXD_W0_CIPHER_ERROR);
}

if (rxdesc->cipher != CIPHER_NONE) {
_rt2x00_desc_read(entry_priv->desc, 2, &rxdesc->iv);
_rt2x00_desc_read(entry_priv->desc, 3, &rxdesc->eiv);
_rt2x00_desc_read(entry_priv->desc, 4, &rxdesc->icv);

/*
* Hardware has stripped IV/EIV data from 802.11 frame during
* decryption. It has provided the data seperately but rt2x00lib
* should decide if it should be reinserted.
*/
rxdesc->flags |= RX_FLAG_IV_STRIPPED;

/*
* FIXME: Legacy driver indicates that the frame does
* contain the Michael Mic. Unfortunately, in rt2x00
* the MIC seems to be missing completely...
*/
rxdesc->flags |= RX_FLAG_MMIC_STRIPPED;

if (rxdesc->cipher_status == RX_CRYPTO_SUCCESS)
rxdesc->flags |= RX_FLAG_DECRYPTED;
else if (rxdesc->cipher_status == RX_CRYPTO_FAIL_MIC)
rxdesc->flags |= RX_FLAG_MMIC_ERROR;
}

/*
* Obtain the status about this packet.
* When frame was received with an OFDM bitrate,
* the signal is the PLCP value. If it was received with
* a CCK bitrate the signal is the rate in 100kbit/s.
*/
rxdesc->signal = rt2x00_get_field32(word1, RXD_W1_SIGNAL);
rxdesc->rssi = rt61pci_agc_to_rssi(entry->queue->rt2x00dev, word1);
rxdesc->rssi = rt61pci_agc_to_rssi(rt2x00dev, word1);
rxdesc->size = rt2x00_get_field32(word0, RXD_W0_DATABYTE_COUNT);

if (rt2x00_get_field32(word0, RXD_W0_OFDM))
Expand Down Expand Up @@ -2355,6 +2595,7 @@ static int rt61pci_probe_hw(struct rt2x00_dev *rt2x00dev)
*/
__set_bit(DRIVER_REQUIRE_FIRMWARE, &rt2x00dev->flags);
__set_bit(DRIVER_REQUIRE_DMA, &rt2x00dev->flags);
__set_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags);

/*
* Set the rssi offset.
Expand Down Expand Up @@ -2404,6 +2645,7 @@ static const struct ieee80211_ops rt61pci_mac80211_ops = {
.config = rt2x00mac_config,
.config_interface = rt2x00mac_config_interface,
.configure_filter = rt2x00mac_configure_filter,
.set_key = rt2x00mac_set_key,
.get_stats = rt2x00mac_get_stats,
.set_retry_limit = rt61pci_set_retry_limit,
.bss_info_changed = rt2x00mac_bss_info_changed,
Expand Down Expand Up @@ -2432,6 +2674,8 @@ static const struct rt2x00lib_ops rt61pci_rt2x00_ops = {
.write_beacon = rt61pci_write_beacon,
.kick_tx_queue = rt61pci_kick_tx_queue,
.fill_rxdone = rt61pci_fill_rxdone,
.config_shared_key = rt61pci_config_shared_key,
.config_pairwise_key = rt61pci_config_pairwise_key,
.config_filter = rt61pci_config_filter,
.config_intf = rt61pci_config_intf,
.config_erp = rt61pci_config_erp,
Expand Down
21 changes: 19 additions & 2 deletions drivers/net/wireless/rt2x00/rt61pci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,16 @@
#define PAIRWISE_KEY_TABLE_BASE 0x1200
#define PAIRWISE_TA_TABLE_BASE 0x1a00

#define SHARED_KEY_ENTRY(__idx) \
( SHARED_KEY_TABLE_BASE + \
((__idx) * sizeof(struct hw_key_entry)) )
#define PAIRWISE_KEY_ENTRY(__idx) \
( PAIRWISE_KEY_TABLE_BASE + \
((__idx) * sizeof(struct hw_key_entry)) )
#define PAIRWISE_TA_ENTRY(__idx) \
( PAIRWISE_TA_TABLE_BASE + \
((__idx) * sizeof(struct hw_pairwise_ta_entry)) )

struct hw_key_entry {
u8 key[16];
u8 tx_mic[8];
Expand All @@ -142,7 +152,8 @@ struct hw_key_entry {

struct hw_pairwise_ta_entry {
u8 address[6];
u8 reserved[2];
u8 cipher;
u8 reserved;
} __attribute__ ((packed));

/*
Expand Down Expand Up @@ -662,6 +673,10 @@ struct hw_pairwise_ta_entry {
* SEC_CSR4: Pairwise key table lookup control.
*/
#define SEC_CSR4 0x30b0
#define SEC_CSR4_ENABLE_BSS0 FIELD32(0x00000001)
#define SEC_CSR4_ENABLE_BSS1 FIELD32(0x00000002)
#define SEC_CSR4_ENABLE_BSS2 FIELD32(0x00000004)
#define SEC_CSR4_ENABLE_BSS3 FIELD32(0x00000008)

/*
* SEC_CSR5: shared key table security mode register.
Expand Down Expand Up @@ -1428,8 +1443,10 @@ struct hw_pairwise_ta_entry {

/*
* Word4
* ICV: Received ICV of originally encrypted.
* NOTE: This is a guess, the official definition is "reserved"
*/
#define RXD_W4_RESERVED FIELD32(0xffffffff)
#define RXD_W4_ICV FIELD32(0xffffffff)

/*
* the above 20-byte is called RXINFO and will be DMAed to MAC RX block
Expand Down

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