From 23f68d462984bfda47c7bf663dca347e8e3df549 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 7 Feb 2022 19:25:08 +0100 Subject: netfilter: nft_cmp: optimize comparison for 16-bytes Allow up to 16-byte comparisons with a new cmp fast version. Use two 64-bit words and calculate the mask representing the bits to be compared. Make sure the comparison is 64-bit aligned and avoid out-of-bound memory access on registers. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'net/netfilter/nf_tables_core.c') diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index 36e73f9828c5..c6c05b2412c4 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -67,6 +67,20 @@ static void nft_cmp_fast_eval(const struct nft_expr *expr, regs->verdict.code = NFT_BREAK; } +static void nft_cmp16_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + const u64 *reg_data = (const u64 *)®s->data[priv->sreg]; + const u64 *mask = (const u64 *)&priv->mask; + const u64 *data = (const u64 *)&priv->data; + + if (((reg_data[0] & mask[0]) == data[0] && + ((reg_data[1] & mask[1]) == data[1])) ^ priv->inv) + return; + regs->verdict.code = NFT_BREAK; +} + static noinline void __nft_trace_verdict(struct nft_traceinfo *info, const struct nft_chain *chain, const struct nft_regs *regs) @@ -225,6 +239,8 @@ next_rule: nft_rule_dp_for_each_expr(expr, last, rule) { if (expr->ops == &nft_cmp_fast_ops) nft_cmp_fast_eval(expr, ®s); + else if (expr->ops == &nft_cmp16_fast_ops) + nft_cmp16_fast_eval(expr, ®s); else if (expr->ops == &nft_bitwise_fast_ops) nft_bitwise_fast_eval(expr, ®s); else if (expr->ops != &nft_payload_fast_ops || -- cgit v1.2.3