iwlagn: rewrite HW crypto

As I just discovered while doing WoWLAN, HW crypto
is done wrong for GTKs: they should be programmed
for the AP station ID (in the managed mode case)
and the HW can actually deal with multiple group
keys per station as well (which is useful in IBSS
RSN but that I've chosen not to use this).

To fix all this, modify the way keys are sent to
the device and key offsets are allocated. After
these changes, key offsets are stored into the
hw_key_idx which we can then track for the key
lifetime, not relying on our sta_cmd array. WEP
default keys get special treatment, of course.

Additionally, since I had the API for it, we can
now pre-fill TKIP phase 1 keys for RX now that we
can obtain the P1K from mac80211, a capability I
had added for WoWLAN initially.

Finally, some keys simply don't need to be added
into the device's key cache -- a key that won't
be used for RX is only needed in the TX header,
so "pretend" to have accepted any key without
adding it into the device -- no need to use up
key space there for it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

1 files changed, 31 insertions, 23 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 6df2443..0bab195 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2259,14 +2259,8 @@ static void iwlagn_mac_update_tkip_key(struct ieee80211_hw *hw,
 				       u32 iv32, u16 *phase1key)
 {
 	struct iwl_priv *priv = hw->priv;
-	struct iwl_vif_priv *vif_priv = (void *)vif->drv_priv;
-
-	IWL_DEBUG_MAC80211(priv, "enter\n");
 
-	iwl_update_tkip_key(priv, vif_priv->ctx, keyconf, sta,
-			    iv32, phase1key);
-
-	IWL_DEBUG_MAC80211(priv, "leave\n");
+	iwl_update_tkip_key(priv, vif, keyconf, sta, iv32, phase1key);
 }
 
 static int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
@@ -2278,7 +2272,6 @@ static int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	struct iwl_vif_priv *vif_priv = (void *)vif->drv_priv;
 	struct iwl_rxon_context *ctx = vif_priv->ctx;
 	int ret;
-	u8 sta_id;
 	bool is_default_wep_key = false;
 
 	IWL_DEBUG_MAC80211(priv, "enter\n");
@@ -2289,20 +2282,27 @@ static int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	}
 
 	/*
-	 * To support IBSS RSN, don't program group keys in IBSS, the
-	 * hardware will then not attempt to decrypt the frames.
+	 * We could program these keys into the hardware as well, but we
+	 * don't expect much multicast traffic in IBSS and having keys
+	 * for more stations is probably more useful.
+	 *
+	 * Mark key TX-only and return 0.
 	 */
 	if (vif->type == NL80211_IFTYPE_ADHOC &&
-	    !(key->flags & IEEE80211_KEY_FLAG_PAIRWISE))
-		return -EOPNOTSUPP;
+	    !(key->flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
+		key->hw_key_idx = WEP_INVALID_OFFSET;
+		return 0;
+	}
 
-	sta_id = iwl_sta_id_or_broadcast(priv, vif_priv->ctx, sta);
-	if (sta_id == IWL_INVALID_STATION)
-		return -EINVAL;
+	/* If they key was TX-only, accept deletion */
+	if (cmd == DISABLE_KEY && key->hw_key_idx == WEP_INVALID_OFFSET)
+		return 0;
 
 	mutex_lock(&priv->mutex);
 	iwl_scan_cancel_timeout(priv, 100);
 
+	BUILD_BUG_ON(WEP_INVALID_OFFSET == IWLAGN_HW_KEY_DEFAULT);
+
 	/*
 	 * If we are getting WEP group key and we didn't receive any key mapping
 	 * so far, we are in legacy wep mode (group key only), otherwise we are
@@ -2310,22 +2310,30 @@ static int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	 * In legacy wep mode, we use another host command to the uCode.
 	 */
 	if ((key->cipher == WLAN_CIPHER_SUITE_WEP40 ||
-	     key->cipher == WLAN_CIPHER_SUITE_WEP104) &&
-	    !sta) {
+	     key->cipher == WLAN_CIPHER_SUITE_WEP104) && !sta) {
 		if (cmd == SET_KEY)
 			is_default_wep_key = !ctx->key_mapping_keys;
 		else
 			is_default_wep_key =
-					(key->hw_key_idx == HW_KEY_DEFAULT);
+				key->hw_key_idx == IWLAGN_HW_KEY_DEFAULT;
 	}
 
+
 	switch (cmd) {
 	case SET_KEY:
-		if (is_default_wep_key)
+		if (is_default_wep_key) {
 			ret = iwl_set_default_wep_key(priv, vif_priv->ctx, key);
-		else
-			ret = iwl_set_dynamic_key(priv, vif_priv->ctx,
-						  key, sta_id);
+			break;
+		}
+		ret = iwl_set_dynamic_key(priv, vif_priv->ctx, key, sta);
+		if (ret) {
+			/*
+			 * can't add key for RX, but we don't need it
+			 * in the device for TX so still return 0
+			 */
+			ret = 0;
+			key->hw_key_idx = WEP_INVALID_OFFSET;
+		}
 
 		IWL_DEBUG_MAC80211(priv, "enable hwcrypto key\n");
 		break;
@@ -2333,7 +2341,7 @@ static int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 		if (is_default_wep_key)
 			ret = iwl_remove_default_wep_key(priv, ctx, key);
 		else
-			ret = iwl_remove_dynamic_key(priv, ctx, key, sta_id);
+			ret = iwl_remove_dynamic_key(priv, ctx, key, sta);
 
 		IWL_DEBUG_MAC80211(priv, "disable hwcrypto key\n");
 		break;