Re: [B.A.T.M.A.N.] [PATCH maint] batman-adv: Fix transmission of final, 16th fragment

["Linus Lüssing" <linus.luessing@c0d3.blue>]

On Mon, Feb 13, 2017 at 08:44:31PM +0100, Linus Lüssing wrote:
> Trying to split and transmit a unicast packet in 16 parts will fail for
> the final fragment: After having sent the 15th one with a frag_packet.no
> index of 14, we will increase the the index to 15 - and return with an
> error code immediately, even though one more fragment is due for
> transmission and allowed.
> 
> Fixing this issue by moving the check before incrementing the index.
> 
> While at it, adding an unlikely(), because the check is actually more of
> an assertion.
> 
> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
> 
> ---
> 
> Compile time tested only
> ---
>  net/batman-adv/fragmentation.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
> index 0854ebd..f181868 100644
> --- a/net/batman-adv/fragmentation.c
> +++ b/net/batman-adv/fragmentation.c
> @@ -499,6 +499,12 @@ int batadv_frag_send_packet(struct sk_buff *skb,

And one more thing which seems fishy to me in this function:

526         /* Make room for the fragment header. */
527         if (batadv_skb_head_push(skb, header_size) < 0 ||
528             pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) {
529                 ret = -ENOMEM;
530                 goto put_primary_if;
531         }
532 
533         memcpy(skb->data, &frag_header, header_size);


For the pskb_expand_head() case, there is an skb_push(header_size) missing,
isn't it?