diff options
| author | Jeremy Sowden <jeremy@azazel.net> | 2020-01-19 10:58:01 +0000 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-01-22 23:06:56 +0100 |
| commit | f833cb3c9ce4174671eb2c55d458221b4c00dd48 (patch) | |
| tree | be199f6050d709450bd2f3a888ae8bf1eb7d53dc | |
| parent | 844ee4cebf45d326890ddbd3d1d124f4fc9b80ad (diff) | |
include: nf_tables: correct bitwise header comment.
The comment documenting how bitwise expressions work includes a table
which summarizes the mask and xor arguments combined to express the
supported boolean operations. However, the row for OR:
mask xor
0 x
is incorrect.
dreg = (sreg & 0) ^ x
is not equivalent to:
dreg = sreg | x
What the code actually does is:
dreg = (sreg & ~x) ^ x
Update the documentation to match.
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | include/linux/netfilter/nf_tables.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index c556ccd3..42ed5ca3 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -491,15 +491,16 @@ enum nft_immediate_attributes { * @NFTA_BITWISE_MASK: mask value (NLA_NESTED: nft_data_attributes) * @NFTA_BITWISE_XOR: xor value (NLA_NESTED: nft_data_attributes) * - * The bitwise expression performs the following operation: + * The bitwise expression supports boolean and shift operations. It implements + * the boolean operations by performing the following operation: * * dreg = (sreg & mask) ^ xor * - * which allow to express all bitwise operations: + * with these mask and xor values: * * mask xor * NOT: 1 1 - * OR: 0 x + * OR: ~x x * XOR: 1 x * AND: x 0 */ |