diff options
| author | Phil Sutter <phil@nwl.cc> | 2018-03-16 00:03:19 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-03-16 09:58:39 +0100 |
| commit | 6979625686ec8d915f5ad5fdc28f24f55b6be3f7 (patch) | |
| tree | e358bb0c0335622f99c374386ba2f1d8d2dbf20d /src/parser_bison.y | |
| parent | 70b31b1ce73e704d4387b1262e8b97785ffe64f7 (diff) | |
relational: Eliminate meta OPs
With a bit of code reorganization, relational meta OPs OP_RANGE,
OP_FLAGCMP and OP_LOOKUP become unused and can be removed. The only meta
OP left is OP_IMPLICIT which is usually treated as alias to OP_EQ.
Though it needs to stay in place for one reason: When matching against a
bitmask (e.g. TCP flags or conntrack states), it has a different
meaning:
| nft --debug=netlink add rule ip t c tcp flags syn
| ip t c
| [ meta load l4proto => reg 1 ]
| [ cmp eq reg 1 0x00000006 ]
| [ payload load 1b @ transport header + 13 => reg 1 ]
| [ bitwise reg 1 = (reg=1 & 0x00000002 ) ^ 0x00000000 ]
| [ cmp neq reg 1 0x00000000 ]
| nft --debug=netlink add rule ip t c tcp flags == syn
| ip t c
| [ meta load l4proto => reg 1 ]
| [ cmp eq reg 1 0x00000006 ]
| [ payload load 1b @ transport header + 13 => reg 1 ]
| [ cmp eq reg 1 0x00000002 ]
OP_IMPLICIT creates a match which just checks the given flag is present,
while OP_EQ creates a match which ensures the given flag and no other is
present.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/parser_bison.y')
| -rw-r--r-- | src/parser_bison.y | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/parser_bison.y b/src/parser_bison.y index 6fba7e59..bdf2fb49 100644 --- a/src/parser_bison.y +++ b/src/parser_bison.y @@ -3185,7 +3185,7 @@ relational_expr : expr /* implicit */ rhs_expr } | expr /* implicit */ list_rhs_expr { - $$ = relational_expr_alloc(&@$, OP_FLAGCMP, $1, $2); + $$ = relational_expr_alloc(&@$, OP_IMPLICIT, $1, $2); } | expr relational_op rhs_expr { |