From 6979625686ec8d915f5ad5fdc28f24f55b6be3f7 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 16 Mar 2018 00:03:19 +0100 Subject: 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 Signed-off-by: Pablo Neira Ayuso --- src/netlink_linearize.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) (limited to 'src/netlink_linearize.c') diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index be1c750c..dce8f5ce 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -297,6 +297,7 @@ static enum nft_cmp_ops netlink_gen_cmp_op(enum ops op) { switch (op) { case OP_EQ: + case OP_IMPLICIT: return NFT_CMP_EQ; case OP_NEQ: return NFT_CMP_NEQ; @@ -316,6 +317,9 @@ static enum nft_cmp_ops netlink_gen_cmp_op(enum ops op) static void netlink_gen_range(struct netlink_linearize_ctx *ctx, const struct expr *expr, enum nft_registers dreg); +static void netlink_gen_flagcmp(struct netlink_linearize_ctx *ctx, + const struct expr *expr, + enum nft_registers dreg); static struct expr *netlink_gen_prefix(struct netlink_linearize_ctx *ctx, const struct expr *expr, @@ -362,6 +366,8 @@ static void netlink_gen_cmp(struct netlink_linearize_ctx *ctx, case EXPR_SET: case EXPR_SET_REF: return netlink_gen_lookup(ctx, expr, dreg); + case EXPR_LIST: + return netlink_gen_flagcmp(ctx, expr, dreg); case EXPR_PREFIX: sreg = get_register(ctx, expr->left); if (expr_basetype(expr->left)->type != TYPE_STRING) { @@ -376,6 +382,11 @@ static void netlink_gen_cmp(struct netlink_linearize_ctx *ctx, } break; default: + if (expr->op == OP_IMPLICIT && + expr->right->dtype->basetype != NULL && + expr->right->dtype->basetype->type == TYPE_BITMASK) + return netlink_gen_flagcmp(ctx, expr, dreg); + sreg = get_register(ctx, expr->left); len = div_round_up(expr->right->len, BITS_PER_BYTE); right = expr->right; @@ -421,8 +432,8 @@ static void netlink_gen_range(struct netlink_linearize_ctx *ctx, nld.value, nld.len); nftnl_rule_add_expr(ctx->nlr, nle); break; - case OP_RANGE: case OP_EQ: + case OP_IMPLICIT: nle = alloc_nft_expr("cmp"); netlink_put_register(nle, NFTNL_EXPR_CMP_SREG, sreg); nftnl_expr_set_u32(nle, NFTNL_EXPR_CMP_OP, @@ -491,6 +502,7 @@ static void netlink_gen_relational(struct netlink_linearize_ctx *ctx, enum nft_registers dreg) { switch (expr->op) { + case OP_IMPLICIT: case OP_EQ: case OP_NEQ: case OP_LT: @@ -498,12 +510,6 @@ static void netlink_gen_relational(struct netlink_linearize_ctx *ctx, case OP_LTE: case OP_GTE: return netlink_gen_cmp(ctx, expr, dreg); - case OP_RANGE: - return netlink_gen_range(ctx, expr, dreg); - case OP_FLAGCMP: - return netlink_gen_flagcmp(ctx, expr, dreg); - case OP_LOOKUP: - return netlink_gen_lookup(ctx, expr, dreg); default: BUG("invalid relational operation %u\n", expr->op); } -- cgit v1.2.3