From d9e7891476057b24a1acbf10a491e5b9a1c4ae77 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 3 Jan 2023 13:47:17 +0100 Subject: [PATCH] netfilter: nf_tables: avoid retpoline overhead for some ct expression calls nft_ct expression cannot be made builtin to nf_tables without also forcing the conntrack itself to be builtin. However, this can be avoided by splitting retrieval of a few selector keys that only need to access the nf_conn structure, i.e. no function calls to nf_conntrack code. Many rulesets start with something like "ct status established,related accept" With this change, this no longer requires an indirect call, which gives about 1.8% more throughput with a simple conntrack-enabled forwarding test (retpoline thunk used). Signed-off-by: Florian Westphal --- include/net/netfilter/nf_tables_core.h | 12 ++++++ net/netfilter/Makefile | 6 +++ net/netfilter/nf_tables_core.c | 3 ++ net/netfilter/nft_ct.c | 39 ++++++++++++------ net/netfilter/nft_ct_fast.c | 56 ++++++++++++++++++++++++++ 5 files changed, 104 insertions(+), 12 deletions(-) create mode 100644 net/netfilter/nft_ct_fast.c diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h index bedef373ec21..780a5f6ad4a6 100644 --- a/include/net/netfilter/nf_tables_core.h +++ b/include/net/netfilter/nf_tables_core.h @@ -61,6 +61,16 @@ struct nft_immediate_expr { extern const struct nft_expr_ops nft_cmp_fast_ops; extern const struct nft_expr_ops nft_cmp16_fast_ops; +struct nft_ct { + enum nft_ct_keys key:8; + enum ip_conntrack_dir dir:8; + u8 len; + union { + u8 dreg; + u8 sreg; + }; +}; + struct nft_payload { enum nft_payload_bases base:8; u8 offset; @@ -140,6 +150,8 @@ void nft_rt_get_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt); void nft_counter_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt); +void nft_ct_get_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs, const struct nft_pktinfo *pkt); enum { NFT_PAYLOAD_CTX_INNER_TUN = (1 << 0), diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 3754eb06fb41..ba2a6b5e93d9 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -98,6 +98,12 @@ nf_tables-objs += nft_set_pipapo_avx2.o endif endif +ifdef CONFIG_NFT_CT +ifdef CONFIG_RETPOLINE +nf_tables-objs += nft_ct_fast.o +endif +endif + obj-$(CONFIG_NF_TABLES) += nf_tables.o obj-$(CONFIG_NFT_COMPAT) += nft_compat.o obj-$(CONFIG_NFT_CONNLIMIT) += nft_connlimit.o diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index d9992906199f..6ecd0ba2e546 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -228,6 +228,9 @@ static void expr_call_ops_eval(const struct nft_expr *expr, X(e, nft_counter_eval); X(e, nft_meta_get_eval); X(e, nft_lookup_eval); +#if IS_ENABLED(CONFIG_NFT_CT) + X(e, nft_ct_get_fast_eval); +#endif X(e, nft_range_eval); X(e, nft_immediate_eval); X(e, nft_byteorder_eval); diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index c68e2151defe..b9c84499438b 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -12,7 +12,7 @@ #include #include #include -#include +#include #include #include #include @@ -23,16 +23,6 @@ #include #include -struct nft_ct { - enum nft_ct_keys key:8; - enum ip_conntrack_dir dir:8; - u8 len; - union { - u8 dreg; - u8 sreg; - }; -}; - struct nft_ct_helper_obj { struct nf_conntrack_helper *helper4; struct nf_conntrack_helper *helper6; @@ -759,6 +749,18 @@ static bool nft_ct_set_reduce(struct nft_regs_track *track, return false; } +#ifdef CONFIG_RETPOLINE +static const struct nft_expr_ops nft_ct_get_fast_ops = { + .type = &nft_ct_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_ct)), + .eval = nft_ct_get_fast_eval, + .init = nft_ct_get_init, + .destroy = nft_ct_get_destroy, + .dump = nft_ct_get_dump, + .reduce = nft_ct_set_reduce, +}; +#endif + static const struct nft_expr_ops nft_ct_set_ops = { .type = &nft_ct_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_ct)), @@ -791,8 +793,21 @@ nft_ct_select_ops(const struct nft_ctx *ctx, if (tb[NFTA_CT_DREG] && tb[NFTA_CT_SREG]) return ERR_PTR(-EINVAL); - if (tb[NFTA_CT_DREG]) + if (tb[NFTA_CT_DREG]) { +#ifdef CONFIG_RETPOLINE + u32 k = ntohl(nla_get_be32(tb[NFTA_CT_KEY])); + + switch (k) { + case NFT_CT_STATE: + case NFT_CT_DIRECTION: + case NFT_CT_STATUS: + case NFT_CT_MARK: + case NFT_CT_SECMARK: + return &nft_ct_get_fast_ops; + } +#endif return &nft_ct_get_ops; + } if (tb[NFTA_CT_SREG]) { #ifdef CONFIG_NF_CONNTRACK_ZONES diff --git a/net/netfilter/nft_ct_fast.c b/net/netfilter/nft_ct_fast.c new file mode 100644 index 000000000000..89983b0613fa --- /dev/null +++ b/net/netfilter/nft_ct_fast.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0-only +#if IS_ENABLED(CONFIG_NFT_CT) +#include +#include +#include + +void nft_ct_get_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_ct *priv = nft_expr_priv(expr); + u32 *dest = ®s->data[priv->dreg]; + enum ip_conntrack_info ctinfo; + const struct nf_conn *ct; + unsigned int state; + + ct = nf_ct_get(pkt->skb, &ctinfo); + if (!ct) { + regs->verdict.code = NFT_BREAK; + return; + } + + switch (priv->key) { + case NFT_CT_STATE: + if (ct) + state = NF_CT_STATE_BIT(ctinfo); + else if (ctinfo == IP_CT_UNTRACKED) + state = NF_CT_STATE_UNTRACKED_BIT; + else + state = NF_CT_STATE_INVALID_BIT; + *dest = state; + return; + case NFT_CT_DIRECTION: + nft_reg_store8(dest, CTINFO2DIR(ctinfo)); + return; + case NFT_CT_STATUS: + *dest = ct->status; + return; +#ifdef CONFIG_NF_CONNTRACK_MARK + case NFT_CT_MARK: + *dest = ct->mark; + return; +#endif +#ifdef CONFIG_NF_CONNTRACK_SECMARK + case NFT_CT_SECMARK: + *dest = ct->secmark; + return; +#endif + default: + WARN_ON_ONCE(1); + regs->verdict.code = NFT_BREAK; + break; + } +} +EXPORT_SYMBOL_GPL(nft_ct_get_fast_eval); +#endif