[PATCH] mac80211: add debugfs file for mic failure

[PATCH] mac80211: add debugfs file for mic failure

[Saravana]

The mic failure count will provide the number of mic failure that 
have happened without a countermeasure being started. Once the 
countermeasure is started, the counter will be reset to 0.
This count will be helpful when the consecutive 
mic failure occur at intervals greater than 60 seconds regularly(frequently).

Signed-off-by: Saravana <saravanad@posedge.com>
---
 net/mac80211/debugfs_key.c |   18 ++++++++++++++++++
 net/mac80211/key.h         |    3 +++
 net/mac80211/wpa.c         |    2 ++
 3 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/debugfs_key.c b/net/mac80211/debugfs_key.c
index 2d42354..b85386e 100644
--- a/net/mac80211/debugfs_key.c
+++ b/net/mac80211/debugfs_key.c
@@ -199,6 +199,23 @@ static ssize_t key_icverrors_read(struct file *file, char __user *userbuf,
 }
 KEY_OPS(icverrors);
 
+static ssize_t key_mic_failures_read(struct file *file, char __user *userbuf,
+					size_t count, loff_t *ppos)
+
+{
+	struct ieee80211_key *key = file->private_data;
+	char buf[20];
+	int len;
+
+	if (key->conf.cipher != WLAN_CIPHER_SUITE_TKIP)
+		return -EINVAL;
+	len = scnprintf(buf, sizeof(buf), "%u\n",
+			key->u.tkip.mic_failures);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+KEY_OPS(mic_failures);
+
 static ssize_t key_key_read(struct file *file, char __user *userbuf,
 			    size_t count, loff_t *ppos)
 {
@@ -260,6 +277,7 @@ void ieee80211_debugfs_key_add(struct ieee80211_key *key)
 	DEBUGFS_ADD(rx_spec);
 	DEBUGFS_ADD(replays);
 	DEBUGFS_ADD(icverrors);
+	DEBUGFS_ADD(mic_failures);
 	DEBUGFS_ADD(key);
 	DEBUGFS_ADD(ifindex);
 };
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index 7cff0d3..382dc44 100644
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -81,6 +81,9 @@ struct ieee80211_key {
 
 			/* last received RSC */
 			struct tkip_ctx rx[IEEE80211_NUM_TIDS];
+
+			/* number of mic failures */
+			u32 mic_failures;
 		} tkip;
 		struct {
 			atomic64_t tx_pn;
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 8bd2f5c..aad79f3 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -161,6 +161,8 @@ update_iv:
 	return RX_CONTINUE;
 
 mic_fail:
+
+	rx->key->u.tkip.mic_failures++;
 	/*
 	 * In some cases the key can be unset - e.g. a multicast packet, in
 	 * a driver that supports HW encryption. Send up the key idx only if 

Re: [PATCH] mac80211: add debugfs file for mic failure

[Saravana]

> +static ssize_t key_mic_failures_read(struct file *file, char __user *userbuf,
> +					size_t count, loff_t *ppos)
> +
There is an extra line below the function header.
This will be removed in the Patch v2.
> +{

[PATCH] mac80211: add debugfs file for mic failure

[Saravana]

Add a debugfs file showing the number of dropped
rx packet due to mic failures. currently the
number of rx packet dropped is counted in general and
not with respect to a specific reason. This patch
counts the number of packet drop due to mic failure.

Signed-off-by: Saravana <saravanad@posedge.com>
---
 net/mac80211/debugfs_sta.c |    1 +
 net/mac80211/sta_info.h    |    3 +++
 net/mac80211/wpa.c         |    1 +
 3 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 49a1c70..dcdbc2c 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -413,6 +413,7 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta)
 	DEBUGFS_ADD_COUNTER(rx_duplicates, num_duplicates);
 	DEBUGFS_ADD_COUNTER(rx_fragments, rx_fragments);
 	DEBUGFS_ADD_COUNTER(rx_dropped, rx_dropped);
+	DEBUGFS_ADD_COUNTER(rx_dropped_mic_failure, rx_dropped_mic_failure);
 	DEBUGFS_ADD_COUNTER(tx_fragments, tx_fragments);
 	DEBUGFS_ADD_COUNTER(tx_filtered, tx_filtered_count);
 	DEBUGFS_ADD_COUNTER(tx_retry_failed, tx_retry_failed);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 1489bca..a0c2165 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -248,6 +248,8 @@ struct sta_ampdu_mlme {
  * @num_duplicates: number of duplicate frames received from this STA
  * @rx_fragments: number of received MPDUs
  * @rx_dropped: number of dropped MPDUs from this STA
+ * @rx_dropped_mic_failure: number of dropped MPDUs
+ *	due to mic failure from this STA
  * @last_signal: signal of last received frame from this STA
  * @avg_signal: moving average of signal of received frames from this STA
  * @last_ack_signal: signal of last received Ack frame from this STA
@@ -328,6 +330,7 @@ struct sta_info {
 	unsigned long num_duplicates;
 	unsigned long rx_fragments;
 	unsigned long rx_dropped;
+	unsigned long rx_dropped_mic_failure;
 	int last_signal;
 	struct ewma avg_signal;
 	int last_ack_signal;
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 8bd2f5c..960403e 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -166,6 +166,7 @@ mic_fail:
 	 * a driver that supports HW encryption. Send up the key idx only if
 	 * the key is set.
 	 */
+	rx->sta->rx_dropped_mic_failure++;
 	mac80211_ev_michael_mic_failure(rx->sdata,
 					rx->key ? rx->key->conf.keyidx : -1,
 					(void *) skb->data, NULL, GFP_ATOMIC);

Re: [PATCH] mac80211: add debugfs file for mic failure

[Johannes Berg]

On Fri, 2012-11-30 at 13:41 +0530, Saravana wrote:
> Add a debugfs file showing the number of dropped
> rx packet due to mic failures. currently the
> number of rx packet dropped is counted in general and
> not with respect to a specific reason. This patch
> counts the number of packet drop due to mic failure.

It would make more sense to count them per *key*, not per station, and
counting them per station like this can crash anyway if sta is NULL.

johannes

Re: [PATCH] mac80211: add debugfs file for mic failure

[Saravana]

On 11/30/2012 05:11 PM, Johannes Berg wrote:
> On Fri, 2012-11-30 at 13:41 +0530, Saravana wrote:
>> Add a debugfs file showing the number of dropped
>> rx packet due to mic failures. currently the
>> number of rx packet dropped is counted in general and
>> not with respect to a specific reason. This patch
>> counts the number of packet drop due to mic failure.
> 
> It would make more sense to count them per *key*, not per station, and
> counting them per station like this can crash anyway if sta is NULL.
> 
I agree with you. I will prepare the patch per key instead of per station.
> johannes
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>