linux/Documentation/networking/dsa
Vladimir Oltean 4e50025129 net: dsa: generalize overhead for taggers that use both headers and trailers
Some really really weird switches just couldn't decide whether to use a
normal or a tail tagger, so they just did both.

This creates problems for DSA, because we only have the concept of an
'overhead' which can be applied to the headroom or to the tailroom of
the skb (like for example during the central TX reallocation procedure),
depending on the value of bool tail_tag, but not to both.

We need to generalize DSA to cater for these odd switches by
transforming the 'overhead / tail_tag' pair into 'needed_headroom /
needed_tailroom'.

The DSA master's MTU is increased to account for both.

The flow dissector code is modified such that it only calls the DSA
adjustment callback if the tagger has a non-zero header length.

Taggers are trivially modified to declare either needed_headroom or
needed_tailroom, based on the tail_tag value that they currently
declare.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-11 12:45:38 -07:00
..
b53.rst Documentation: net: dsa: b53: Describe b53 configuration 2019-07-08 15:30:13 -07:00
bcm_sf2.rst Documentation: net: dsa: transition to the rst format 2019-04-12 16:48:35 -07:00
configuration.rst Documentation: networking: dsa: mention that the master is brought up automatically 2021-03-17 12:34:35 -07:00
dsa.rst net: dsa: generalize overhead for taggers that use both headers and trailers 2021-06-11 12:45:38 -07:00
index.rst Documentation: net: dsa: b53: Describe b53 configuration 2019-07-08 15:30:13 -07:00
lan9303.rst Documentation: net: dsa: transition to the rst format 2019-04-12 16:48:35 -07:00
sja1105.rst docs: networkng: fix lists and table in sja1105 2020-06-10 16:39:09 -07:00