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, 4 insertions, 5 deletions

diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 0f5a69ed746d..d0191c53cbd8 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -92,6 +92,7 @@ static int lowpan_header_create(struct sk_buff *skb,
         const u8 *saddr = _saddr;
         const u8 *daddr = _daddr;
         struct ieee802154_addr sa, da;
+        struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 
         /* TODO:
          * if this package isn't ipv6 one, where should it be routed?
@@ -115,8 +116,7 @@ static int lowpan_header_create(struct sk_buff *skb,
          * from MAC subif of the 'dev' and 'real_dev' network devices, but
          * this isn't implemented in mainline yet, so currently we assign 0xff
          */
-        mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
-        mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
+        cb->type = IEEE802154_FC_TYPE_DATA;
 
         /* prepare wpan address data */
         sa.mode = IEEE802154_ADDR_LONG;
@@ -135,11 +135,10 @@ static int lowpan_header_create(struct sk_buff *skb,
         } else {
                 da.mode = IEEE802154_ADDR_LONG;
                 da.extended_addr = ieee802154_devaddr_from_raw(daddr);
-
-                /* request acknowledgment */
-                mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
         }
 
+        cb->ackreq = !lowpan_is_addr_broadcast(daddr);
+
         return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
                         type, (void *)&da, (void *)&sa, 0);
 }