ieee802154: change needed headroom/tailroom

[deliverable/linux.git] / net / mac802154 / iface.c

diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
index 8afe26d729710021c3707d815bdd2bebb994fc96..b5a0936ce514eaa2706a036d715ad28427a9d2ae 100644 (file)
--- a/net/mac802154/iface.c
+++ b/net/mac802154/iface.c
@@ -537,8 +537,18 @@ static void ieee802154_if_setup(struct net_device *dev)
        dev->addr_len           = IEEE802154_EXTENDED_ADDR_LEN;
        memset(dev->broadcast, 0xff, IEEE802154_EXTENDED_ADDR_LEN);
 
-       dev->hard_header_len    = MAC802154_FRAME_HARD_HEADER_LEN;
-       dev->needed_tailroom    = 2 + 16; /* FCS + MIC */
+       /* Let hard_header_len set to IEEE802154_MIN_HEADER_LEN. AF_PACKET
+        * will not send frames without any payload, but ack frames
+        * has no payload, so substract one that we can send a 3 bytes
+        * frame. The xmit callback assumes at least a hard header where two
+        * bytes fc and sequence field are set.
+        */
+       dev->hard_header_len    = IEEE802154_MIN_HEADER_LEN - 1;
+       /* The auth_tag header is for security and places in private payload
+        * room of mac frame which stucks between payload and FCS field.
+        */
+       dev->needed_tailroom    = IEEE802154_MAX_AUTH_TAG_LEN +
+                                 IEEE802154_FCS_LEN;
        dev->mtu                = IEEE802154_MTU;
        dev->tx_queue_len       = 300;
        dev->flags              = IFF_NOARP | IFF_BROADCAST;
@@ -617,7 +627,8 @@ ieee802154_if_add(struct ieee802154_local *local, const char *name,
        if (!ndev)
                return ERR_PTR(-ENOMEM);
 
-       ndev->needed_headroom = local->hw.extra_tx_headroom;
+       ndev->needed_headroom = local->hw.extra_tx_headroom +
+                               IEEE802154_MAX_HEADER_LEN;
 
        ret = dev_alloc_name(ndev, ndev->name);
        if (ret < 0)