![Pablo Neira Ayuso](/assets/img/avatar_default.png)
Add the corresponding trace if we have a full match in a non-terminal rule. Note that the traces will look slightly different than in x_tables since the log message after all expressions have been evaluated (contrary to x_tables, that emits it before the target action). This manifests in two differences in nf_tables wrt. x_tables: 1) The rule that enables the tracing is included in the trace. 2) If the rule emits some log message, that is shown before the trace log message. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
270 lines
6.4 KiB
C
270 lines
6.4 KiB
C
/*
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* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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/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/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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static void nft_cmp_fast_eval(const struct nft_expr *expr,
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struct nft_data data[NFT_REG_MAX + 1])
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{
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const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
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u32 mask = nft_cmp_fast_mask(priv->len);
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if ((data[priv->sreg].data[0] & mask) == priv->data)
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return;
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data[NFT_REG_VERDICT].verdict = NFT_BREAK;
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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_data data[NFT_REG_MAX + 1],
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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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struct nft_data *dest = &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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ptr = skb_network_header(skb) + pkt->xt.thoff;
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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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if (priv->len == 2)
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*(u16 *)dest->data = *(u16 *)ptr;
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else if (priv->len == 4)
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*(u32 *)dest->data = *(u32 *)ptr;
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else
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*(u8 *)dest->data = *(u8 *)ptr;
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return true;
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}
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struct nft_jumpstack {
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const struct nft_chain *chain;
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const struct nft_rule *rule;
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int rulenum;
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};
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enum nft_trace {
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NFT_TRACE_RULE,
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NFT_TRACE_RETURN,
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NFT_TRACE_POLICY,
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};
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static const char *const comments[] = {
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[NFT_TRACE_RULE] = "rule",
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[NFT_TRACE_RETURN] = "return",
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[NFT_TRACE_POLICY] = "policy",
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};
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static struct nf_loginfo trace_loginfo = {
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.type = NF_LOG_TYPE_LOG,
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.u = {
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.log = {
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.level = 4,
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.logflags = NF_LOG_MASK,
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},
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},
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};
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static void nft_trace_packet(const struct nft_pktinfo *pkt,
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const struct nft_chain *chain,
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int rulenum, enum nft_trace type)
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{
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struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
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nf_log_packet(net, pkt->xt.family, pkt->ops->hooknum, pkt->skb, pkt->in,
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pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
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chain->table->name, chain->name, comments[type],
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rulenum);
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}
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unsigned int
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nft_do_chain(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
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{
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const struct nft_chain *chain = ops->priv, *basechain = chain;
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const struct nft_rule *rule;
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const struct nft_expr *expr, *last;
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struct nft_data data[NFT_REG_MAX + 1];
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unsigned int stackptr = 0;
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struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
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struct nft_stats __percpu *stats;
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int rulenum;
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/*
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* Cache cursor to avoid problems in case that the cursor is updated
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* while traversing the ruleset.
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*/
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unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor);
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do_chain:
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rulenum = 0;
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rule = list_entry(&chain->rules, struct nft_rule, list);
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next_rule:
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data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
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list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
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/* This rule is not active, skip. */
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if (unlikely(rule->genmask & (1 << gencursor)))
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continue;
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rulenum++;
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nft_rule_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, data);
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else if (expr->ops != &nft_payload_fast_ops ||
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!nft_payload_fast_eval(expr, data, pkt))
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expr->ops->eval(expr, data, pkt);
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if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
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break;
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}
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switch (data[NFT_REG_VERDICT].verdict) {
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case NFT_BREAK:
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data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
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continue;
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case NFT_CONTINUE:
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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
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continue;
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}
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break;
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}
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switch (data[NFT_REG_VERDICT].verdict & 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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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
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return data[NFT_REG_VERDICT].verdict;
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}
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switch (data[NFT_REG_VERDICT].verdict) {
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case NFT_JUMP:
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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
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BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
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jumpstack[stackptr].chain = chain;
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jumpstack[stackptr].rule = rule;
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jumpstack[stackptr].rulenum = rulenum;
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stackptr++;
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chain = data[NFT_REG_VERDICT].chain;
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goto do_chain;
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case NFT_GOTO:
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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
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chain = data[NFT_REG_VERDICT].chain;
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goto do_chain;
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case NFT_RETURN:
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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);
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break;
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case NFT_CONTINUE:
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if (unlikely(pkt->skb->nf_trace && !(chain->flags & NFT_BASE_CHAIN)))
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nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);
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break;
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default:
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WARN_ON(1);
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}
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if (stackptr > 0) {
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stackptr--;
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chain = jumpstack[stackptr].chain;
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rule = jumpstack[stackptr].rule;
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rulenum = jumpstack[stackptr].rulenum;
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goto next_rule;
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}
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if (unlikely(pkt->skb->nf_trace))
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nft_trace_packet(pkt, basechain, -1, NFT_TRACE_POLICY);
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rcu_read_lock_bh();
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stats = rcu_dereference(nft_base_chain(basechain)->stats);
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__this_cpu_inc(stats->pkts);
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__this_cpu_add(stats->bytes, pkt->skb->len);
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rcu_read_unlock_bh();
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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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int __init nf_tables_core_module_init(void)
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{
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int err;
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err = nft_immediate_module_init();
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if (err < 0)
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goto err1;
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err = nft_cmp_module_init();
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if (err < 0)
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goto err2;
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err = nft_lookup_module_init();
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if (err < 0)
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goto err3;
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err = nft_bitwise_module_init();
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if (err < 0)
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goto err4;
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err = nft_byteorder_module_init();
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if (err < 0)
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goto err5;
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err = nft_payload_module_init();
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if (err < 0)
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goto err6;
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return 0;
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err6:
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nft_byteorder_module_exit();
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err5:
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nft_bitwise_module_exit();
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err4:
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nft_lookup_module_exit();
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err3:
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nft_cmp_module_exit();
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err2:
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nft_immediate_module_exit();
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err1:
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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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nft_payload_module_exit();
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nft_byteorder_module_exit();
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nft_bitwise_module_exit();
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nft_lookup_module_exit();
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nft_cmp_module_exit();
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nft_immediate_module_exit();
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}
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