tree 293edbea3ef99f0c9c78de37a5d9dbb1b12791d7
parent 8252fceac01570836f0cb9e922f56b4c0b1011df
author Jon Maloy <jon.maloy@ericsson.com> 1510777436 +0100
committer David S. Miller <davem@davemloft.net> 1510796940 +0900

tipc: enforce valid ratio between skb truesize and contents

The socket level flow control is based on the assumption that incoming
buffers meet the condition (skb->truesize / roundup(skb->len) <= 4),
where the latter value is rounded off upwards to the nearest 1k number.
This does empirically hold true for the device drivers we know, but we
cannot trust that it will always be so, e.g., in a system with jumbo
frames and very small packets.

We now introduce a check for this condition at packet arrival, and if
we find it to be false, we copy the packet to a new, smaller buffer,
where the condition will be true. We expect this to affect only a small
fraction of all incoming packets, if at all.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>