net: 6lowpan: fix reserved space for single frames
This patch fixes patch add handling to take care tail and headroom for
single 6lowpan frames. We need to be sure we have a skb with the right
head and tailroom for single frames. This patch do it by using
skb_copy_expand() if head and tailroom is not enough allocated by upper
layer.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195059
Reported-by: David Palma <[email protected]>
Reported-by: Rabi Narayan Sahoo <[email protected]>
Cc: [email protected]
Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: Stefan Schmidt <[email protected]>
diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
index e6ff512..ca53efa 100644
--- a/net/ieee802154/6lowpan/tx.c
+++ b/net/ieee802154/6lowpan/tx.c
@@ -265,9 +265,24 @@ netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
/* We must take a copy of the skb before we modify/replace the ipv6
* header as the header could be used elsewhere
*/
- skb = skb_unshare(skb, GFP_ATOMIC);
- if (!skb)
- return NET_XMIT_DROP;
+ if (unlikely(skb_headroom(skb) < ldev->needed_headroom ||
+ skb_tailroom(skb) < ldev->needed_tailroom)) {
+ struct sk_buff *nskb;
+
+ nskb = skb_copy_expand(skb, ldev->needed_headroom,
+ ldev->needed_tailroom, GFP_ATOMIC);
+ if (likely(nskb)) {
+ consume_skb(skb);
+ skb = nskb;
+ } else {
+ kfree_skb(skb);
+ return NET_XMIT_DROP;
+ }
+ } else {
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (!skb)
+ return NET_XMIT_DROP;
+ }
ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
if (ret < 0) {
