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>

2 files changed, 13 insertions, 15 deletions

diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index 03855b0677cc..0597b96dc9ba 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -59,8 +59,6 @@ mac802154_subif_rx(struct ieee802154_dev *hw, struct sk_buff *skb, u8 lqi)
         skb->protocol = htons(ETH_P_IEEE802154);
         skb_reset_mac_header(skb);
 
-        BUILD_BUG_ON(sizeof(struct ieee802154_mac_cb) > sizeof(skb->cb));
-
         if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
                 u16 crc;
 
diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index cb34064d05f6..bb49e88c460f 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -192,15 +192,17 @@ static int mac802154_header_create(struct sk_buff *skb,
 {
         struct ieee802154_hdr hdr;
         struct mac802154_sub_if_data *priv = netdev_priv(dev);
+        struct ieee802154_mac_cb *cb = mac_cb(skb);
         int hlen;
 
         if (!daddr)
                 return -EINVAL;
 
         memset(&hdr.fc, 0, sizeof(hdr.fc));
-        hdr.fc.type = mac_cb_type(skb);
-        hdr.fc.security_enabled = mac_cb_is_secen(skb);
-        hdr.fc.ack_request = mac_cb_is_ackreq(skb);
+        hdr.fc.type = cb->type;
+        hdr.fc.security_enabled = cb->secen;
+        hdr.fc.ack_request = cb->ackreq;
+        hdr.seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
 
         if (!saddr) {
                 spin_lock_bh(&priv->mib_lock);
@@ -391,12 +393,12 @@ mac802154_subif_frame(struct mac802154_sub_if_data *sdata, struct sk_buff *skb)
         sdata->dev->stats.rx_packets++;
         sdata->dev->stats.rx_bytes += skb->len;
 
-        switch (mac_cb_type(skb)) {
+        switch (mac_cb(skb)->type) {
         case IEEE802154_FC_TYPE_DATA:
                 return mac802154_process_data(sdata->dev, skb);
         default:
                 pr_warn("ieee802154: bad frame received (type = %d)\n",
-                        mac_cb_type(skb));
+                        mac_cb(skb)->type);
                 kfree_skb(skb);
                 return NET_RX_DROP;
         }
@@ -423,6 +425,7 @@ static int mac802154_parse_frame_start(struct sk_buff *skb)
 {
         int hlen;
         struct ieee802154_hdr hdr;
+        struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 
         hlen = ieee802154_hdr_pull(skb, &hdr);
         if (hlen < 0)
@@ -433,18 +436,15 @@ static int mac802154_parse_frame_start(struct sk_buff *skb)
         pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr.fc),
                  hdr.seq);
 
-        mac_cb(skb)->flags = hdr.fc.type;
-
-        if (hdr.fc.ack_request)
-                mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
-        if (hdr.fc.security_enabled)
-                mac_cb(skb)->flags |= MAC_CB_FLAG_SECEN;
+        cb->type = hdr.fc.type;
+        cb->ackreq = hdr.fc.ack_request;
+        cb->secen = hdr.fc.security_enabled;
 
         mac802154_print_addr("destination", &hdr.dest);
         mac802154_print_addr("source", &hdr.source);
 
-        mac_cb(skb)->source = hdr.source;
-        mac_cb(skb)->dest = hdr.dest;
+        cb->source = hdr.source;
+        cb->dest = hdr.dest;
 
         if (hdr.fc.security_enabled) {
                 u64 key;