2009-04-11 01:58:06

by Christian Lamparter

[permalink] [raw]
Subject: [PATCH 1/2] p54: utilize all available key slots for decryption offload

This patch takes care of outstanding TODOs:
/* TODO: some devices have 4 more free slots for rx keys */

Now the driver can utilize all available key slots instead of just 4.
Obviously, this helps most in AP/IBSS(/MESH) mode, when
we have to use more different keys.

Signed-off-by: Christian Lamparter <[email protected]>
---
Two more patches form an older stash.

I'll wait until wireless-testing is "synced" before
flooding the tubes with the "split p54common" series.
Of course ar9170usb is on hold for the same reason...

Regards,
Chr
---
diff --git a/drivers/net/wireless/p54/p54.h b/drivers/net/wireless/p54/p54.h
index fe8bca4..fadee60 100644
--- a/drivers/net/wireless/p54/p54.h
+++ b/drivers/net/wireless/p54/p54.h
@@ -187,6 +187,7 @@ struct p54_common {
/* cryptographic engine information */
u8 privacy_caps;
u8 rx_keycache_size;
+ unsigned long *used_rxkeys;

/* LED management */
#ifdef CONFIG_P54_LEDS
diff --git a/drivers/net/wireless/p54/p54common.c b/drivers/net/wireless/p54/p54common.c
index 2f55662..d57e0ca 100644
--- a/drivers/net/wireless/p54/p54common.c
+++ b/drivers/net/wireless/p54/p54common.c
@@ -181,7 +181,7 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw)
dev->queues = P54_QUEUE_AC_NUM;
}

- if (!modparam_nohwcrypt)
+ if (!modparam_nohwcrypt) {
printk(KERN_INFO "%s: cryptographic accelerator "
"WEP:%s, TKIP:%s, CCMP:%s\n",
wiphy_name(dev->wiphy),
@@ -191,6 +191,26 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw)
(priv->privacy_caps & BR_DESC_PRIV_CAP_AESCCMP) ?
"YES" : "no");

+ if (priv->rx_keycache_size) {
+ /*
+ * NOTE:
+ *
+ * The firmware provides at most 255 (0 - 254) slots
+ * for keys which are then used to offload decryption.
+ * As a result the 255 entry (aka 0xff) can be used
+ * safely by the driver to mark keys that didn't fit
+ * into the full cache. This trick saves us from
+ * keeping a extra list for uploaded keys.
+ */
+
+ priv->used_rxkeys = kzalloc(BITS_TO_LONGS(
+ priv->rx_keycache_size), GFP_KERNEL);
+
+ if (!priv->used_rxkeys)
+ return -ENOMEM;
+ }
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(p54_parse_firmware);
@@ -2544,61 +2564,84 @@ static int p54_set_key(struct ieee80211_hw *dev, enum set_key_cmd cmd,
struct p54_common *priv = dev->priv;
struct sk_buff *skb;
struct p54_keycache *rxkey;
+ int slot, ret = 0;
u8 algo = 0;

if (modparam_nohwcrypt)
return -EOPNOTSUPP;

- if (cmd == DISABLE_KEY)
- algo = 0;
- else {
+ mutex_lock(&priv->conf_mutex);
+ if (cmd == SET_KEY) {
switch (key->alg) {
case ALG_TKIP:
if (!(priv->privacy_caps & (BR_DESC_PRIV_CAP_MICHAEL |
- BR_DESC_PRIV_CAP_TKIP)))
- return -EOPNOTSUPP;
+ BR_DESC_PRIV_CAP_TKIP))) {
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
+ }
key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
algo = P54_CRYPTO_TKIPMICHAEL;
break;
case ALG_WEP:
- if (!(priv->privacy_caps & BR_DESC_PRIV_CAP_WEP))
- return -EOPNOTSUPP;
+ if (!(priv->privacy_caps & BR_DESC_PRIV_CAP_WEP)) {
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
+ }
key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
algo = P54_CRYPTO_WEP;
break;
case ALG_CCMP:
- if (!(priv->privacy_caps & BR_DESC_PRIV_CAP_AESCCMP))
- return -EOPNOTSUPP;
+ if (!(priv->privacy_caps & BR_DESC_PRIV_CAP_AESCCMP)) {
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
+ }
key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
algo = P54_CRYPTO_AESCCMP;
break;
default:
- return -EOPNOTSUPP;
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
}
- }
+ slot = bitmap_find_free_region(priv->used_rxkeys,
+ priv->rx_keycache_size, 0);

- if (key->keyidx > priv->rx_keycache_size) {
- /*
- * The device supports the choosen algorithm, but the firmware
- * does not provide enough key slots to store all of them.
- * So, incoming frames have to be decoded by the mac80211 stack,
- * but we can still offload encryption for outgoing frames.
- */
+ if (slot < 0) {
+ /*
+ * The device supports the choosen algorithm, but the
+ * firmware does not provide enough key slots to store
+ * all of them.
+ * But encryption offload for outgoing frames is always
+ * possible, so we just pretend that the upload was
+ * successful and do the decryption in software.
+ */

- return 0;
+ /* mark the key as invalid. */
+ key->hw_key_idx = 0xff;
+ goto out_unlock;
+ }
+ } else {
+ slot = key->hw_key_idx;
+
+ if (slot == 0xff) {
+ /* This key was not uploaded into the rx key cache. */
+
+ goto out_unlock;
+ }
+
+ bitmap_release_region(priv->used_rxkeys, slot, 0);
+ algo = 0;
}

- mutex_lock(&priv->conf_mutex);
skb = p54_alloc_skb(dev, P54_HDR_FLAG_CONTROL_OPSET, sizeof(*rxkey),
- P54_CONTROL_TYPE_RX_KEYCACHE, GFP_ATOMIC);
+ P54_CONTROL_TYPE_RX_KEYCACHE, GFP_KERNEL);
if (!skb) {
- mutex_unlock(&priv->conf_mutex);
- return -ENOMEM;
+ bitmap_release_region(priv->used_rxkeys, slot, 0);
+ ret = -ENOSPC;
+ goto out_unlock;
}

- /* TODO: some devices have 4 more free slots for rx keys */
rxkey = (struct p54_keycache *)skb_put(skb, sizeof(*rxkey));
- rxkey->entry = key->keyidx;
+ rxkey->entry = slot;
rxkey->key_id = key->keyidx;
rxkey->key_type = algo;
if (sta)
@@ -2616,8 +2659,11 @@ static int p54_set_key(struct ieee80211_hw *dev, enum set_key_cmd cmd,
}

priv->tx(dev, skb);
+ key->hw_key_idx = slot;
+
+out_unlock:
mutex_unlock(&priv->conf_mutex);
- return 0;
+ return ret;
}

#ifdef CONFIG_P54_LEDS
@@ -2858,6 +2904,7 @@ void p54_free_common(struct ieee80211_hw *dev)
kfree(priv->iq_autocal);
kfree(priv->output_limit);
kfree(priv->curve_data);
+ kfree(priv->used_rxkeys);

#ifdef CONFIG_P54_LEDS
p54_unregister_leds(dev);