wireless: move sequence number arithmetic to ieee80211.h

Move the sequence number arithmetic code from mac80211 to
ieee80211.h so others can use it. Also rename the functions
from _seq to _sn, they operate on the sequence number, not
the sequence_control field.

Also move macros to convert the sequence control to/from
the sequence number value from various drivers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 7e24fe0cfbcd..a0c550fb65a6 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -113,6 +113,34 @@
 #define IEEE80211_CTL_EXT_SSW_FBACK     0x9000
 #define IEEE80211_CTL_EXT_SSW_ACK       0xa000
 
+
+#define IEEE80211_SN_MASK               ((IEEE80211_SCTL_SEQ) >> 4)
+#define IEEE80211_MAX_SN                IEEE80211_SN_MASK
+#define IEEE80211_SN_MODULO             (IEEE80211_MAX_SN + 1)
+
+static inline int ieee80211_sn_less(u16 sn1, u16 sn2)
+{
+        return ((sn1 - sn2) & IEEE80211_SN_MASK) > (IEEE80211_SN_MODULO >> 1);
+}
+
+static inline u16 ieee80211_sn_add(u16 sn1, u16 sn2)
+{
+        return (sn1 + sn2) & IEEE80211_SN_MASK;
+}
+
+static inline u16 ieee80211_sn_inc(u16 sn)
+{
+        return ieee80211_sn_add(sn, 1);
+}
+
+static inline u16 ieee80211_sn_sub(u16 sn1, u16 sn2)
+{
+        return (sn1 - sn2) & IEEE80211_SN_MASK;
+}
+
+#define IEEE80211_SEQ_TO_SN(seq)        (((seq) & IEEE80211_SCTL_SEQ) >> 4)
+#define IEEE80211_SN_TO_SEQ(ssn)        (((ssn) << 4) & IEEE80211_SCTL_SEQ)
+
 /* miscellaneous IEEE 802.11 constants */
 #define IEEE80211_MAX_FRAG_THRESHOLD    2352
 #define IEEE80211_MAX_RTS_THRESHOLD     2353