ieee802154: change _cb handling slightly

The current mac_cb handling of ieee802154 is rather awkward and limited.
Decompose the single flags field into multiple fields with the meanings
of each subfield of the flags field to make future extensions (for
example, link-layer security) easier. Also don't set the frame sequence
number in upper layers, since that's a thing the MAC is supposed to set
on frame transmit - we set it on header creation, but assuming that
upper layers do not blindly duplicate our headers, this is fine.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 18 deletions

diff --git a/include/net/ieee802154_netdev.h b/include/net/ieee802154_netdev.h
index 6e4d3e1071b5..bc9a7475e57e 100644
--- a/include/net/ieee802154_netdev.h
+++ b/include/net/ieee802154_netdev.h
@@ -222,8 +222,9 @@ static inline void ieee802154_addr_to_sa(struct ieee802154_addr_sa *sa,
  */
 struct ieee802154_mac_cb {
         u8 lqi;
-        u8 flags;
-        u8 seq;
+        u8 type;
+        bool ackreq;
+        bool secen;
         struct ieee802154_addr source;
         struct ieee802154_addr dest;
 };
@@ -233,24 +234,12 @@ static inline struct ieee802154_mac_cb *mac_cb(struct sk_buff *skb)
         return (struct ieee802154_mac_cb *)skb->cb;
 }
 
-#define MAC_CB_FLAG_TYPEMASK            ((1 << 3) - 1)
-
-#define MAC_CB_FLAG_ACKREQ              (1 << 3)
-#define MAC_CB_FLAG_SECEN               (1 << 4)
-
-static inline bool mac_cb_is_ackreq(struct sk_buff *skb)
-{
-        return mac_cb(skb)->flags & MAC_CB_FLAG_ACKREQ;
-}
-
-static inline bool mac_cb_is_secen(struct sk_buff *skb)
+static inline struct ieee802154_mac_cb *mac_cb_init(struct sk_buff *skb)
 {
-        return mac_cb(skb)->flags & MAC_CB_FLAG_SECEN;
-}
+        BUILD_BUG_ON(sizeof(struct ieee802154_mac_cb) > sizeof(skb->cb));
 
-static inline int mac_cb_type(struct sk_buff *skb)
-{
-        return mac_cb(skb)->flags & MAC_CB_FLAG_TYPEMASK;
+        memset(skb->cb, 0, sizeof(struct ieee802154_mac_cb));
+        return mac_cb(skb);
 }
 
 #define IEEE802154_MAC_SCAN_ED          0