diff options
Diffstat (limited to 'net/netfilter/nf_tables_core.c')
| -rw-r--r-- | net/netfilter/nf_tables_core.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c new file mode 100644 index 000000000..b0d711d49 --- /dev/null +++ b/net/netfilter/nf_tables_core.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> + * + * Development of this code funded by Astaro AG (http://www.astaro.com/) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/rculist.h> +#include <linux/skbuff.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/static_key.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nf_log.h> +#include <net/netfilter/nft_meta.h> + +static noinline void __nft_trace_packet(struct nft_traceinfo *info, + const struct nft_chain *chain, + enum nft_trace_types type) +{ + const struct nft_pktinfo *pkt = info->pkt; + + if (!info->trace || !pkt->skb->nf_trace) + return; + + info->chain = chain; + info->type = type; + + nft_trace_notify(info); +} + +static inline void nft_trace_packet(struct nft_traceinfo *info, + const struct nft_chain *chain, + const struct nft_rule *rule, + enum nft_trace_types type) +{ + if (static_branch_unlikely(&nft_trace_enabled)) { + info->rule = rule; + __nft_trace_packet(info, chain, type); + } +} + +static void nft_bitwise_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs) +{ + const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr); + u32 *src = ®s->data[priv->sreg]; + u32 *dst = ®s->data[priv->dreg]; + + *dst = (*src & priv->mask) ^ priv->xor; +} + +static void nft_cmp_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs) +{ + const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + + if (((regs->data[priv->sreg] & priv->mask) == priv->data) ^ priv->inv) + return; + 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) +{ + enum nft_trace_types type; + + switch (regs->verdict.code) { + case NFT_CONTINUE: + case NFT_RETURN: + type = NFT_TRACETYPE_RETURN; + break; + default: + type = NFT_TRACETYPE_RULE; + break; + } + + __nft_trace_packet(info, chain, type); +} + +static inline void nft_trace_verdict(struct nft_traceinfo *info, + const struct nft_chain *chain, + const struct nft_rule *rule, + const struct nft_regs *regs) +{ + if (static_branch_unlikely(&nft_trace_enabled)) { + info->rule = rule; + __nft_trace_verdict(info, chain, regs); + } +} + +static bool nft_payload_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_payload *priv = nft_expr_priv(expr); + const struct sk_buff *skb = pkt->skb; + u32 *dest = ®s->data[priv->dreg]; + unsigned char *ptr; + + if (priv->base == NFT_PAYLOAD_NETWORK_HEADER) + ptr = skb_network_header(skb); + else { + if (!pkt->tprot_set) + return false; + ptr = skb_network_header(skb) + nft_thoff(pkt); + } + + ptr += priv->offset; + + if (unlikely(ptr + priv->len > skb_tail_pointer(skb))) + return false; + + *dest = 0; + if (priv->len == 2) + *(u16 *)dest = *(u16 *)ptr; + else if (priv->len == 4) + *(u32 *)dest = *(u32 *)ptr; + else + *(u8 *)dest = *(u8 *)ptr; + return true; +} + +DEFINE_STATIC_KEY_FALSE(nft_counters_enabled); + +static noinline void nft_update_chain_stats(const struct nft_chain *chain, + const struct nft_pktinfo *pkt) +{ + struct nft_base_chain *base_chain; + struct nft_stats __percpu *pstats; + struct nft_stats *stats; + + base_chain = nft_base_chain(chain); + + rcu_read_lock(); + pstats = READ_ONCE(base_chain->stats); + if (pstats) { + local_bh_disable(); + stats = this_cpu_ptr(pstats); + u64_stats_update_begin(&stats->syncp); + stats->pkts++; + stats->bytes += pkt->skb->len; + u64_stats_update_end(&stats->syncp); + local_bh_enable(); + } + rcu_read_unlock(); +} + +struct nft_jumpstack { + const struct nft_chain *chain; + struct nft_rule *const *rules; +}; + +static void expr_call_ops_eval(const struct nft_expr *expr, + struct nft_regs *regs, + struct nft_pktinfo *pkt) +{ +#ifdef CONFIG_RETPOLINE + unsigned long e = (unsigned long)expr->ops->eval; +#define X(e, fun) \ + do { if ((e) == (unsigned long)(fun)) \ + return fun(expr, regs, pkt); } while (0) + + X(e, nft_payload_eval); + X(e, nft_cmp_eval); + X(e, nft_meta_get_eval); + X(e, nft_lookup_eval); + X(e, nft_range_eval); + X(e, nft_immediate_eval); + X(e, nft_byteorder_eval); + X(e, nft_dynset_eval); + X(e, nft_rt_get_eval); + X(e, nft_bitwise_eval); +#undef X +#endif /* CONFIG_RETPOLINE */ + expr->ops->eval(expr, regs, pkt); +} + +unsigned int +nft_do_chain(struct nft_pktinfo *pkt, void *priv) +{ + const struct nft_chain *chain = priv, *basechain = chain; + const struct net *net = nft_net(pkt); + struct nft_rule *const *rules; + const struct nft_rule *rule; + const struct nft_expr *expr, *last; + struct nft_regs regs = {}; + unsigned int stackptr = 0; + struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE]; + bool genbit = READ_ONCE(net->nft.gencursor); + struct nft_traceinfo info; + + info.trace = false; + if (static_branch_unlikely(&nft_trace_enabled)) + nft_trace_init(&info, pkt, ®s.verdict, basechain); +do_chain: + if (genbit) + rules = rcu_dereference(chain->rules_gen_1); + else + rules = rcu_dereference(chain->rules_gen_0); + +next_rule: + rule = *rules; + regs.verdict.code = NFT_CONTINUE; + for (; *rules ; rules++) { + rule = *rules; + nft_rule_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 || + !nft_payload_fast_eval(expr, ®s, pkt)) + expr_call_ops_eval(expr, ®s, pkt); + + if (regs.verdict.code != NFT_CONTINUE) + break; + } + + switch (regs.verdict.code) { + case NFT_BREAK: + regs.verdict.code = NFT_CONTINUE; + continue; + case NFT_CONTINUE: + nft_trace_packet(&info, chain, rule, + NFT_TRACETYPE_RULE); + continue; + } + break; + } + + nft_trace_verdict(&info, chain, rule, ®s); + + switch (regs.verdict.code & NF_VERDICT_MASK) { + case NF_ACCEPT: + case NF_DROP: + case NF_QUEUE: + case NF_STOLEN: + return regs.verdict.code; + } + + switch (regs.verdict.code) { + case NFT_JUMP: + if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE)) + return NF_DROP; + jumpstack[stackptr].chain = chain; + jumpstack[stackptr].rules = rules + 1; + stackptr++; + fallthrough; + case NFT_GOTO: + chain = regs.verdict.chain; + goto do_chain; + case NFT_CONTINUE: + case NFT_RETURN: + break; + default: + WARN_ON(1); + } + + if (stackptr > 0) { + stackptr--; + chain = jumpstack[stackptr].chain; + rules = jumpstack[stackptr].rules; + goto next_rule; + } + + nft_trace_packet(&info, basechain, NULL, NFT_TRACETYPE_POLICY); + + if (static_branch_unlikely(&nft_counters_enabled)) + nft_update_chain_stats(basechain, pkt); + + return nft_base_chain(basechain)->policy; +} +EXPORT_SYMBOL_GPL(nft_do_chain); + +static struct nft_expr_type *nft_basic_types[] = { + &nft_imm_type, + &nft_cmp_type, + &nft_lookup_type, + &nft_bitwise_type, + &nft_byteorder_type, + &nft_payload_type, + &nft_dynset_type, + &nft_range_type, + &nft_meta_type, + &nft_rt_type, + &nft_exthdr_type, +}; + +static struct nft_object_type *nft_basic_objects[] = { +#ifdef CONFIG_NETWORK_SECMARK + &nft_secmark_obj_type, +#endif +}; + +int __init nf_tables_core_module_init(void) +{ + int err, i, j = 0; + + for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) { + err = nft_register_obj(nft_basic_objects[i]); + if (err) + goto err; + } + + for (j = 0; j < ARRAY_SIZE(nft_basic_types); j++) { + err = nft_register_expr(nft_basic_types[j]); + if (err) + goto err; + } + + return 0; + +err: + while (j-- > 0) + nft_unregister_expr(nft_basic_types[j]); + + while (i-- > 0) + nft_unregister_obj(nft_basic_objects[i]); + + return err; +} + +void nf_tables_core_module_exit(void) +{ + int i; + + i = ARRAY_SIZE(nft_basic_types); + while (i-- > 0) + nft_unregister_expr(nft_basic_types[i]); + + i = ARRAY_SIZE(nft_basic_objects); + while (i-- > 0) + nft_unregister_obj(nft_basic_objects[i]); +} |