mac80211: provide sequence numbers

I've come to think that not providing sequence numbers for
the normal STA mode case was a mistake, at least two drivers
now had to implement code they wouldn't otherwise need, and
I believe at76_usb and adm8211 might be broken.

This patch makes mac80211 assign a sequence number to all
those frames that need one except beacons. That means that
if a driver only implements modes that do not do beaconing
it need not worry about the sequence number.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1deb787ff8dc..819844726dd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -438,6 +438,8 @@ struct ieee80211_sub_if_data {
         struct ieee80211_key *keys[NUM_DEFAULT_KEYS];
         struct ieee80211_key *default_key;
 
+        u16 sequence_number;
+
         /* BSS configuration for this interface. */
         struct ieee80211_bss_conf bss_conf;
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 22494bcf488a..8bcabefa86e0 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -600,8 +600,18 @@ ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
         if (ieee80211_hdrlen(hdr->frame_control) < 24)
                 return TX_CONTINUE;
 
+        /*
+         * Anything but QoS data that has a sequence number field
+         * (is long enough) gets a sequence number from the global
+         * counter.
+         */
         if (!ieee80211_is_data_qos(hdr->frame_control)) {
+                /* driver should assign sequence number */
                 info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
+                /* for pure STA mode without beacons, we can do it */
+                hdr->seq_ctrl = cpu_to_le16(tx->sdata->sequence_number);
+                tx->sdata->sequence_number += 0x10;
+                tx->sdata->sequence_number &= IEEE80211_SCTL_SEQ;
                 return TX_CONTINUE;
         }