netlink: add and use netlink_gen_exthdr_mask

rule ip6 filter input frag frag-off 33

before patch:
 [ exthdr load 1b @ 44 + 2 => reg 1 ]
 [ cmp eq reg 1 0x00002100 ]

We truncated 13bit field to 1 byte.

after patch:
 [ exthdr load 2b @ 44 + 2 => reg 1 ]
 [ bitwise reg 1 = (reg=1 & 0x0000f8ff ) ^ 0x00000000 ]
 [ cmp eq reg 1 0x00000801 ]

- ask for 2 bytes
- mask out the 3 lower bits
- shift the value by 3 so equality test will pass for 33

This causes test failures, will be fixed up in a later patch
(the test suite expects the old, broken input).

It also misses the reverse translation to remove the binop,
find the right template and undo the shift of the value.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

0 files changed, 0 insertions, 0 deletions