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![Florian Westphal](/assets/img/avatar_default.png)
pass it as argument instead. This reduces size of traceinfo to 16 bytes. Total stack usage: nf_tables_core.c:252 nft_do_chain 304 static While its possible to also pass basechain as argument, doing so increases nft_do_chaininfo function size. Unlike pktinfo/verdict/rule the basechain info isn't used in the expression evaluation path. gcc places it on the stack, which results in extra push/pop when it gets passed to the trace helpers as argument rather than as part of the traceinfo structure. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
417 lines
10 KiB
C
417 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rculist.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/static_key.h>
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_log.h>
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#include <net/netfilter/nft_meta.h>
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#if defined(CONFIG_RETPOLINE) && defined(CONFIG_X86)
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static struct static_key_false nf_tables_skip_direct_calls;
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static bool nf_skip_indirect_calls(void)
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{
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return static_branch_likely(&nf_tables_skip_direct_calls);
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}
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static void __init nf_skip_indirect_calls_enable(void)
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{
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if (!cpu_feature_enabled(X86_FEATURE_RETPOLINE))
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static_branch_enable(&nf_tables_skip_direct_calls);
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}
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#else
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static inline bool nf_skip_indirect_calls(void) { return false; }
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static inline void nf_skip_indirect_calls_enable(void) { }
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#endif
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static noinline void __nft_trace_packet(const struct nft_pktinfo *pkt,
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const struct nft_verdict *verdict,
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const struct nft_rule_dp *rule,
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struct nft_traceinfo *info,
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enum nft_trace_types type)
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{
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if (!info->trace || !info->nf_trace)
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return;
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info->type = type;
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nft_trace_notify(pkt, verdict, rule, info);
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}
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static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
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struct nft_verdict *verdict,
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struct nft_traceinfo *info,
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const struct nft_rule_dp *rule,
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enum nft_trace_types type)
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{
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if (static_branch_unlikely(&nft_trace_enabled)) {
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info->nf_trace = pkt->skb->nf_trace;
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__nft_trace_packet(pkt, verdict, rule, info, type);
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}
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}
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static inline void nft_trace_copy_nftrace(const struct nft_pktinfo *pkt,
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struct nft_traceinfo *info)
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{
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if (static_branch_unlikely(&nft_trace_enabled))
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info->nf_trace = pkt->skb->nf_trace;
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}
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static void nft_bitwise_fast_eval(const struct nft_expr *expr,
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struct nft_regs *regs)
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{
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const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
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u32 *src = ®s->data[priv->sreg];
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u32 *dst = ®s->data[priv->dreg];
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*dst = (*src & priv->mask) ^ priv->xor;
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}
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static void nft_cmp_fast_eval(const struct nft_expr *expr,
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struct nft_regs *regs)
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{
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const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
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if (((regs->data[priv->sreg] & priv->mask) == priv->data) ^ priv->inv)
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return;
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regs->verdict.code = NFT_BREAK;
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}
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static void nft_cmp16_fast_eval(const struct nft_expr *expr,
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struct nft_regs *regs)
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{
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const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
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const u64 *reg_data = (const u64 *)®s->data[priv->sreg];
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const u64 *mask = (const u64 *)&priv->mask;
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const u64 *data = (const u64 *)&priv->data;
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if (((reg_data[0] & mask[0]) == data[0] &&
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((reg_data[1] & mask[1]) == data[1])) ^ priv->inv)
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return;
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regs->verdict.code = NFT_BREAK;
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}
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static noinline void __nft_trace_verdict(const struct nft_pktinfo *pkt,
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struct nft_traceinfo *info,
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const struct nft_rule_dp *rule,
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const struct nft_regs *regs)
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{
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enum nft_trace_types type;
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switch (regs->verdict.code) {
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case NFT_CONTINUE:
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case NFT_RETURN:
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type = NFT_TRACETYPE_RETURN;
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break;
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case NF_STOLEN:
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type = NFT_TRACETYPE_RULE;
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/* can't access skb->nf_trace; use copy */
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break;
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default:
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type = NFT_TRACETYPE_RULE;
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if (info->trace)
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info->nf_trace = pkt->skb->nf_trace;
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break;
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}
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__nft_trace_packet(pkt, ®s->verdict, rule, info, type);
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}
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static inline void nft_trace_verdict(const struct nft_pktinfo *pkt,
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struct nft_traceinfo *info,
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const struct nft_rule_dp *rule,
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const struct nft_regs *regs)
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{
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if (static_branch_unlikely(&nft_trace_enabled))
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__nft_trace_verdict(pkt, info, rule, regs);
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}
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static bool nft_payload_fast_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_payload *priv = nft_expr_priv(expr);
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const struct sk_buff *skb = pkt->skb;
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u32 *dest = ®s->data[priv->dreg];
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unsigned char *ptr;
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if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
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ptr = skb_network_header(skb);
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else {
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if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
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return false;
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ptr = skb_network_header(skb) + nft_thoff(pkt);
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}
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ptr += priv->offset;
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if (unlikely(ptr + priv->len > skb_tail_pointer(skb)))
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return false;
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*dest = 0;
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if (priv->len == 2)
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*(u16 *)dest = *(u16 *)ptr;
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else if (priv->len == 4)
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*(u32 *)dest = *(u32 *)ptr;
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else
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*(u8 *)dest = *(u8 *)ptr;
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return true;
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}
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DEFINE_STATIC_KEY_FALSE(nft_counters_enabled);
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static noinline void nft_update_chain_stats(const struct nft_chain *chain,
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const struct nft_pktinfo *pkt)
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{
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struct nft_base_chain *base_chain;
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struct nft_stats __percpu *pstats;
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struct nft_stats *stats;
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base_chain = nft_base_chain(chain);
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pstats = READ_ONCE(base_chain->stats);
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if (pstats) {
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local_bh_disable();
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stats = this_cpu_ptr(pstats);
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u64_stats_update_begin(&stats->syncp);
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stats->pkts++;
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stats->bytes += pkt->skb->len;
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u64_stats_update_end(&stats->syncp);
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local_bh_enable();
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}
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}
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struct nft_jumpstack {
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const struct nft_rule_dp *rule;
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};
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static void expr_call_ops_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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struct nft_pktinfo *pkt)
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{
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#ifdef CONFIG_RETPOLINE
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unsigned long e;
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if (nf_skip_indirect_calls())
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goto indirect_call;
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e = (unsigned long)expr->ops->eval;
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#define X(e, fun) \
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do { if ((e) == (unsigned long)(fun)) \
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return fun(expr, regs, pkt); } while (0)
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X(e, nft_payload_eval);
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X(e, nft_cmp_eval);
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X(e, nft_counter_eval);
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X(e, nft_meta_get_eval);
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X(e, nft_lookup_eval);
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#if IS_ENABLED(CONFIG_NFT_CT)
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X(e, nft_ct_get_fast_eval);
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#endif
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X(e, nft_range_eval);
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X(e, nft_immediate_eval);
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X(e, nft_byteorder_eval);
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X(e, nft_dynset_eval);
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X(e, nft_rt_get_eval);
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X(e, nft_bitwise_eval);
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X(e, nft_objref_eval);
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X(e, nft_objref_map_eval);
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#undef X
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indirect_call:
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#endif /* CONFIG_RETPOLINE */
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expr->ops->eval(expr, regs, pkt);
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}
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#define nft_rule_expr_first(rule) (struct nft_expr *)&rule->data[0]
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#define nft_rule_expr_next(expr) ((void *)expr) + expr->ops->size
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#define nft_rule_expr_last(rule) (struct nft_expr *)&rule->data[rule->dlen]
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#define nft_rule_dp_for_each_expr(expr, last, rule) \
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for ((expr) = nft_rule_expr_first(rule), (last) = nft_rule_expr_last(rule); \
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(expr) != (last); \
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(expr) = nft_rule_expr_next(expr))
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unsigned int
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nft_do_chain(struct nft_pktinfo *pkt, void *priv)
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{
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const struct nft_chain *chain = priv, *basechain = chain;
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const struct net *net = nft_net(pkt);
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const struct nft_expr *expr, *last;
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const struct nft_rule_dp *rule;
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struct nft_regs regs = {};
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unsigned int stackptr = 0;
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struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
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bool genbit = READ_ONCE(net->nft.gencursor);
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struct nft_rule_blob *blob;
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struct nft_traceinfo info;
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info.trace = false;
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if (static_branch_unlikely(&nft_trace_enabled))
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nft_trace_init(&info, pkt, basechain);
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do_chain:
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if (genbit)
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blob = rcu_dereference(chain->blob_gen_1);
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else
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blob = rcu_dereference(chain->blob_gen_0);
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rule = (struct nft_rule_dp *)blob->data;
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next_rule:
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regs.verdict.code = NFT_CONTINUE;
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for (; !rule->is_last ; rule = nft_rule_next(rule)) {
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nft_rule_dp_for_each_expr(expr, last, rule) {
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if (expr->ops == &nft_cmp_fast_ops)
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nft_cmp_fast_eval(expr, ®s);
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else if (expr->ops == &nft_cmp16_fast_ops)
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nft_cmp16_fast_eval(expr, ®s);
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else if (expr->ops == &nft_bitwise_fast_ops)
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nft_bitwise_fast_eval(expr, ®s);
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else if (expr->ops != &nft_payload_fast_ops ||
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!nft_payload_fast_eval(expr, ®s, pkt))
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expr_call_ops_eval(expr, ®s, pkt);
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if (regs.verdict.code != NFT_CONTINUE)
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break;
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}
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switch (regs.verdict.code) {
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case NFT_BREAK:
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regs.verdict.code = NFT_CONTINUE;
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nft_trace_copy_nftrace(pkt, &info);
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continue;
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case NFT_CONTINUE:
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nft_trace_packet(pkt, ®s.verdict, &info, rule,
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NFT_TRACETYPE_RULE);
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continue;
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}
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break;
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}
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nft_trace_verdict(pkt, &info, rule, ®s);
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switch (regs.verdict.code & NF_VERDICT_MASK) {
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case NF_ACCEPT:
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case NF_DROP:
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case NF_QUEUE:
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case NF_STOLEN:
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return regs.verdict.code;
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}
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switch (regs.verdict.code) {
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case NFT_JUMP:
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if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
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return NF_DROP;
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jumpstack[stackptr].rule = nft_rule_next(rule);
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stackptr++;
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fallthrough;
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case NFT_GOTO:
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chain = regs.verdict.chain;
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goto do_chain;
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case NFT_CONTINUE:
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case NFT_RETURN:
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break;
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default:
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WARN_ON_ONCE(1);
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}
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if (stackptr > 0) {
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stackptr--;
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rule = jumpstack[stackptr].rule;
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goto next_rule;
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}
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nft_trace_packet(pkt, ®s.verdict, &info, NULL, NFT_TRACETYPE_POLICY);
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if (static_branch_unlikely(&nft_counters_enabled))
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nft_update_chain_stats(basechain, pkt);
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return nft_base_chain(basechain)->policy;
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}
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EXPORT_SYMBOL_GPL(nft_do_chain);
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static struct nft_expr_type *nft_basic_types[] = {
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&nft_imm_type,
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&nft_cmp_type,
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&nft_lookup_type,
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&nft_bitwise_type,
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&nft_byteorder_type,
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&nft_payload_type,
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&nft_dynset_type,
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&nft_range_type,
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&nft_meta_type,
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&nft_rt_type,
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&nft_exthdr_type,
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&nft_last_type,
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&nft_counter_type,
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&nft_objref_type,
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&nft_inner_type,
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};
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static struct nft_object_type *nft_basic_objects[] = {
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#ifdef CONFIG_NETWORK_SECMARK
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&nft_secmark_obj_type,
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#endif
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&nft_counter_obj_type,
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};
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int __init nf_tables_core_module_init(void)
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{
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int err, i, j = 0;
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nft_counter_init_seqcount();
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for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) {
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err = nft_register_obj(nft_basic_objects[i]);
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if (err)
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goto err;
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}
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for (j = 0; j < ARRAY_SIZE(nft_basic_types); j++) {
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err = nft_register_expr(nft_basic_types[j]);
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if (err)
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goto err;
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}
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nf_skip_indirect_calls_enable();
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return 0;
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err:
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while (j-- > 0)
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nft_unregister_expr(nft_basic_types[j]);
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while (i-- > 0)
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nft_unregister_obj(nft_basic_objects[i]);
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return err;
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}
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void nf_tables_core_module_exit(void)
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{
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int i;
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i = ARRAY_SIZE(nft_basic_types);
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while (i-- > 0)
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nft_unregister_expr(nft_basic_types[i]);
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i = ARRAY_SIZE(nft_basic_objects);
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while (i-- > 0)
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nft_unregister_obj(nft_basic_objects[i]);
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}
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