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orinoco: refactor xmit path
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... so orinoco_usb can share some common functionality.

Handle 802.2 encapsulation and MIC calculation in that function.
The 802.3 header is prepended to the SKB. The calculated MIC is written
to a specified buffer. Also modify the transmit control word that will
be passed onto the hardware to specify whether the MIC is present, and
the key used.

Signed-off-by: David Kilroy <kilroyd@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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@kilroyd @linvjw
kilroyd authored and linvjw committed May 7, 2010
1 parent 3ef83d7 commit bac6faf
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Showing 3 changed files with 155 additions and 111 deletions.
169 changes: 106 additions & 63 deletions drivers/net/wireless/orinoco/main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -339,18 +339,109 @@ EXPORT_SYMBOL(orinoco_change_mtu);
/* Tx path */
/********************************************************************/

/* Add encapsulation and MIC to the existing SKB.
* The main xmit routine will then send the whole lot to the card.
* Need 8 bytes headroom
* Need 8 bytes tailroom
*
* With encapsulated ethernet II frame
* --------
* 803.3 header (14 bytes)
* dst[6]
* -------- src[6]
* 803.3 header (14 bytes) len[2]
* dst[6] 803.2 header (8 bytes)
* src[6] encaps[6]
* len[2] <- leave alone -> len[2]
* -------- -------- <-- 0
* Payload Payload
* ... ...
*
* -------- --------
* MIC (8 bytes)
* --------
*
* returns 0 on success, -ENOMEM on error.
*/
int orinoco_process_xmit_skb(struct sk_buff *skb,
struct net_device *dev,
struct orinoco_private *priv,
int *tx_control,
u8 *mic_buf)
{
struct orinoco_tkip_key *key;
struct ethhdr *eh;
int do_mic;

key = (struct orinoco_tkip_key *) priv->keys[priv->tx_key].key;

do_mic = ((priv->encode_alg == ORINOCO_ALG_TKIP) &&
(key != NULL));

if (do_mic)
*tx_control |= (priv->tx_key << HERMES_MIC_KEY_ID_SHIFT) |
HERMES_TXCTRL_MIC;

eh = (struct ethhdr *)skb->data;

/* Encapsulate Ethernet-II frames */
if (ntohs(eh->h_proto) > ETH_DATA_LEN) { /* Ethernet-II frame */
struct header_struct {
struct ethhdr eth; /* 802.3 header */
u8 encap[6]; /* 802.2 header */
} __attribute__ ((packed)) hdr;
int len = skb->len + sizeof(encaps_hdr) - (2 * ETH_ALEN);

if (skb_headroom(skb) < ENCAPS_OVERHEAD) {
if (net_ratelimit())
printk(KERN_ERR
"%s: Not enough headroom for 802.2 headers %d\n",
dev->name, skb_headroom(skb));
return -ENOMEM;
}

/* Fill in new header */
memcpy(&hdr.eth, eh, 2 * ETH_ALEN);
hdr.eth.h_proto = htons(len);
memcpy(hdr.encap, encaps_hdr, sizeof(encaps_hdr));

/* Make room for the new header, and copy it in */
eh = (struct ethhdr *) skb_push(skb, ENCAPS_OVERHEAD);
memcpy(eh, &hdr, sizeof(hdr));
}

/* Calculate Michael MIC */
if (do_mic) {
size_t len = skb->len - ETH_HLEN;
u8 *mic = &mic_buf[0];

/* Have to write to an even address, so copy the spare
* byte across */
if (skb->len % 2) {
*mic = skb->data[skb->len - 1];
mic++;
}

orinoco_mic(priv->tx_tfm_mic, key->tx_mic,
eh->h_dest, eh->h_source, 0 /* priority */,
skb->data + ETH_HLEN,
len, mic);
}

return 0;
}
EXPORT_SYMBOL(orinoco_process_xmit_skb);

static netdev_tx_t orinoco_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct orinoco_private *priv = ndev_priv(dev);
struct net_device_stats *stats = &priv->stats;
struct orinoco_tkip_key *key;
hermes_t *hw = &priv->hw;
int err = 0;
u16 txfid = priv->txfid;
struct ethhdr *eh;
int tx_control;
unsigned long flags;
int do_mic;
u8 mic_buf[MICHAEL_MIC_LEN+1];

if (!netif_running(dev)) {
printk(KERN_ERR "%s: Tx on stopped device!\n",
Expand Down Expand Up @@ -382,16 +473,12 @@ static netdev_tx_t orinoco_xmit(struct sk_buff *skb, struct net_device *dev)
if (skb->len < ETH_HLEN)
goto drop;

key = (struct orinoco_tkip_key *) priv->keys[priv->tx_key].key;

do_mic = ((priv->encode_alg == ORINOCO_ALG_TKIP) &&
(key != NULL));

tx_control = HERMES_TXCTRL_TX_OK | HERMES_TXCTRL_TX_EX;

if (do_mic)
tx_control |= (priv->tx_key << HERMES_MIC_KEY_ID_SHIFT) |
HERMES_TXCTRL_MIC;
err = orinoco_process_xmit_skb(skb, dev, priv, &tx_control,
&mic_buf[0]);
if (err)
goto drop;

if (priv->has_alt_txcntl) {
/* WPA enabled firmwares have tx_cntl at the end of
Expand Down Expand Up @@ -434,34 +521,6 @@ static netdev_tx_t orinoco_xmit(struct sk_buff *skb, struct net_device *dev)
HERMES_802_3_OFFSET - HERMES_802_11_OFFSET);
}

eh = (struct ethhdr *)skb->data;

/* Encapsulate Ethernet-II frames */
if (ntohs(eh->h_proto) > ETH_DATA_LEN) { /* Ethernet-II frame */
struct header_struct {
struct ethhdr eth; /* 802.3 header */
u8 encap[6]; /* 802.2 header */
} __attribute__ ((packed)) hdr;

/* Strip destination and source from the data */
skb_pull(skb, 2 * ETH_ALEN);

/* And move them to a separate header */
memcpy(&hdr.eth, eh, 2 * ETH_ALEN);
hdr.eth.h_proto = htons(sizeof(encaps_hdr) + skb->len);
memcpy(hdr.encap, encaps_hdr, sizeof(encaps_hdr));

/* Insert the SNAP header */
if (skb_headroom(skb) < sizeof(hdr)) {
printk(KERN_ERR
"%s: Not enough headroom for 802.2 headers %d\n",
dev->name, skb_headroom(skb));
goto drop;
}
eh = (struct ethhdr *) skb_push(skb, sizeof(hdr));
memcpy(eh, &hdr, sizeof(hdr));
}

err = hw->ops->bap_pwrite(hw, USER_BAP, skb->data, skb->len,
txfid, HERMES_802_3_OFFSET);
if (err) {
Expand All @@ -470,32 +529,16 @@ static netdev_tx_t orinoco_xmit(struct sk_buff *skb, struct net_device *dev)
goto busy;
}

/* Calculate Michael MIC */
if (do_mic) {
u8 mic_buf[MICHAEL_MIC_LEN + 1];
u8 *mic;
size_t offset;
size_t len;
if (tx_control & HERMES_TXCTRL_MIC) {
size_t offset = HERMES_802_3_OFFSET + skb->len;
size_t len = MICHAEL_MIC_LEN;

if (skb->len % 2) {
/* MIC start is on an odd boundary */
mic_buf[0] = skb->data[skb->len - 1];
mic = &mic_buf[1];
offset = skb->len - 1;
len = MICHAEL_MIC_LEN + 1;
} else {
mic = &mic_buf[0];
offset = skb->len;
len = MICHAEL_MIC_LEN;
if (offset % 2) {
offset--;
len++;
}

orinoco_mic(priv->tx_tfm_mic, key->tx_mic,
eh->h_dest, eh->h_source, 0 /* priority */,
skb->data + ETH_HLEN, skb->len - ETH_HLEN, mic);

/* Write the MIC */
err = hw->ops->bap_pwrite(hw, USER_BAP, &mic_buf[0], len,
txfid, HERMES_802_3_OFFSET + offset);
txfid, offset);
if (err) {
printk(KERN_ERR "%s: Error %d writing MIC to BAP\n",
dev->name, err);
Expand Down Expand Up @@ -2234,7 +2277,7 @@ int orinoco_if_add(struct orinoco_private *priv,
/* we use the default eth_mac_addr for setting the MAC addr */

/* Reserve space in skb for the SNAP header */
dev->hard_header_len += ENCAPS_OVERHEAD;
dev->needed_headroom = ENCAPS_OVERHEAD;

netif_carrier_off(dev);

Expand Down
6 changes: 6 additions & 0 deletions drivers/net/wireless/orinoco/orinoco.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -200,6 +200,12 @@ extern irqreturn_t orinoco_interrupt(int irq, void *dev_id);
extern void __orinoco_ev_info(struct net_device *dev, hermes_t *hw);
extern void __orinoco_ev_rx(struct net_device *dev, hermes_t *hw);

int orinoco_process_xmit_skb(struct sk_buff *skb,
struct net_device *dev,
struct orinoco_private *priv,
int *tx_control,
u8 *mic);

/* Common ndo functions exported for reuse by orinoco_usb */
int orinoco_open(struct net_device *dev);
int orinoco_stop(struct net_device *dev);
Expand Down
91 changes: 43 additions & 48 deletions drivers/net/wireless/orinoco/orinoco_usb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,7 @@
#include <linux/wireless.h>
#include <linux/firmware.h>

#include "mic.h"
#include "orinoco.h"

#ifndef URB_ASYNC_UNLINK
Expand Down Expand Up @@ -1198,11 +1199,9 @@ static netdev_tx_t ezusb_xmit(struct sk_buff *skb, struct net_device *dev)
struct orinoco_private *priv = ndev_priv(dev);
struct net_device_stats *stats = &priv->stats;
struct ezusb_priv *upriv = priv->card;
u8 mic[MICHAEL_MIC_LEN+1];
int err = 0;
char *p;
struct ethhdr *eh;
int len, data_len, data_off;
__le16 tx_control;
int tx_control;
unsigned long flags;
struct request_context *ctx;
u8 *buf;
Expand All @@ -1222,7 +1221,7 @@ static netdev_tx_t ezusb_xmit(struct sk_buff *skb, struct net_device *dev)

if (orinoco_lock(priv, &flags) != 0) {
printk(KERN_ERR
"%s: orinoco_xmit() called while hw_unavailable\n",
"%s: ezusb_xmit() called while hw_unavailable\n",
dev->name);
return NETDEV_TX_BUSY;
}
Expand All @@ -1232,53 +1231,46 @@ static netdev_tx_t ezusb_xmit(struct sk_buff *skb, struct net_device *dev)
/* Oops, the firmware hasn't established a connection,
silently drop the packet (this seems to be the
safest approach). */
stats->tx_errors++;
orinoco_unlock(priv, &flags);
dev_kfree_skb(skb);
return NETDEV_TX_OK;
goto drop;
}

/* Check packet length */
if (skb->len < ETH_HLEN)
goto drop;

ctx = ezusb_alloc_ctx(upriv, EZUSB_RID_TX, 0);
if (!ctx)
goto fail;
goto busy;

memset(ctx->buf, 0, BULK_BUF_SIZE);
buf = ctx->buf->data;

/* Length of the packet body */
/* FIXME: what if the skb is smaller than this? */
len = max_t(int, skb->len - ETH_HLEN, ETH_ZLEN - ETH_HLEN);

eh = (struct ethhdr *) skb->data;

tx_control = cpu_to_le16(0);
memcpy(buf, &tx_control, sizeof(tx_control));
buf += sizeof(tx_control);
/* Encapsulate Ethernet-II frames */
if (ntohs(eh->h_proto) > ETH_DATA_LEN) { /* Ethernet-II frame */
struct header_struct *hdr = (void *) buf;
buf += sizeof(*hdr);
data_len = len;
data_off = sizeof(tx_control) + sizeof(*hdr);
p = skb->data + ETH_HLEN;

/* 802.3 header */
memcpy(hdr->dest, eh->h_dest, ETH_ALEN);
memcpy(hdr->src, eh->h_source, ETH_ALEN);
hdr->len = htons(data_len + ENCAPS_OVERHEAD);

/* 802.2 header */
memcpy(&hdr->dsap, &encaps_hdr, sizeof(encaps_hdr));

hdr->ethertype = eh->h_proto;
} else { /* IEEE 802.3 frame */
data_len = len + ETH_HLEN;
data_off = sizeof(tx_control);
p = skb->data;
tx_control = 0;

err = orinoco_process_xmit_skb(skb, dev, priv, &tx_control,
&mic[0]);
if (err)
goto drop;

{
__le16 *tx_cntl = (__le16 *)buf;
*tx_cntl = cpu_to_le16(tx_control);
buf += sizeof(*tx_cntl);
}

memcpy(buf, p, data_len);
buf += data_len;
memcpy(buf, skb->data, skb->len);
buf += skb->len;

if (tx_control & HERMES_TXCTRL_MIC) {
u8 *m = mic;
/* Mic has been offset so it can be copied to an even
* address. We're copying eveything anyway, so we
* don't need to copy that first byte. */
if (skb->len % 2)
m++;
memcpy(buf, m, MICHAEL_MIC_LEN);
buf += MICHAEL_MIC_LEN;
}

/* Finally, we actually initiate the send */
netif_stop_queue(dev);
Expand All @@ -1294,20 +1286,23 @@ static netdev_tx_t ezusb_xmit(struct sk_buff *skb, struct net_device *dev)
if (net_ratelimit())
printk(KERN_ERR "%s: Error %d transmitting packet\n",
dev->name, err);
stats->tx_errors++;
goto fail;
goto busy;
}

dev->trans_start = jiffies;
stats->tx_bytes += data_off + data_len;
stats->tx_bytes += skb->len;
goto ok;

orinoco_unlock(priv, &flags);
drop:
stats->tx_errors++;
stats->tx_dropped++;

ok:
orinoco_unlock(priv, &flags);
dev_kfree_skb(skb);

return NETDEV_TX_OK;

fail:
busy:
orinoco_unlock(priv, &flags);
return NETDEV_TX_BUSY;
}
Expand Down

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