Commit b5bc89bf authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso

netfilter: nf_tables: add trace support

This patch adds support for tracing the packet travel through
the ruleset, in a similar fashion to x_tables.
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 0628b123
......@@ -392,6 +392,7 @@ enum nft_chain_flags {
* @list: used internally
* @rcu_head: used internally
* @net: net namespace that this chain belongs to
* @table: table that this chain belongs to
* @handle: chain handle
* @flags: bitmask of enum nft_chain_flags
* @use: number of jump references to this chain
......@@ -403,6 +404,7 @@ struct nft_chain {
struct list_head list;
struct rcu_head rcu_head;
struct net *net;
struct nft_table *table;
u64 handle;
u8 flags;
u16 use;
......
......@@ -979,6 +979,7 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
INIT_LIST_HEAD(&chain->rules);
chain->handle = nf_tables_alloc_handle(table);
chain->net = net;
chain->table = table;
nla_strlcpy(chain->name, name, NFT_CHAIN_MAXNAMELEN);
if (!(table->flags & NFT_TABLE_F_DORMANT) &&
......
......@@ -19,6 +19,7 @@
#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>
static void nft_cmp_fast_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1])
......@@ -63,6 +64,7 @@ static bool nft_payload_fast_eval(const struct nft_expr *expr,
struct nft_jumpstack {
const struct nft_chain *chain;
const struct nft_rule *rule;
int rulenum;
};
static inline void
......@@ -79,6 +81,40 @@ nft_chain_stats(const struct nft_chain *this, const struct nft_pktinfo *pkt,
rcu_read_unlock_bh();
}
enum nft_trace {
NFT_TRACE_RULE,
NFT_TRACE_RETURN,
NFT_TRACE_POLICY,
};
static const char *const comments[] = {
[NFT_TRACE_RULE] = "rule",
[NFT_TRACE_RETURN] = "return",
[NFT_TRACE_POLICY] = "policy",
};
static struct nf_loginfo trace_loginfo = {
.type = NF_LOG_TYPE_LOG,
.u = {
.log = {
.level = 4,
.logflags = NF_LOG_MASK,
},
},
};
static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
const struct nft_chain *chain,
int rulenum, enum nft_trace type)
{
struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
nf_log_packet(net, pkt->xt.family, pkt->hooknum, pkt->skb, pkt->in,
pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
chain->table->name, chain->name, comments[type],
rulenum);
}
unsigned int
nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
{
......@@ -88,6 +124,7 @@ nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
struct nft_data data[NFT_REG_MAX + 1];
unsigned int stackptr = 0;
struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
int rulenum = 0;
/*
* Cache cursor to avoid problems in case that the cursor is updated
* while traversing the ruleset.
......@@ -104,6 +141,8 @@ nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
if (unlikely(rule->genmask & (1 << gencursor)))
continue;
rulenum++;
nft_rule_for_each_expr(expr, last, rule) {
if (expr->ops == &nft_cmp_fast_ops)
nft_cmp_fast_eval(expr, data);
......@@ -129,17 +168,28 @@ nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
case NF_ACCEPT:
case NF_DROP:
case NF_QUEUE:
if (unlikely(pkt->skb->nf_trace))
nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
return data[NFT_REG_VERDICT].verdict;
case NFT_JUMP:
if (unlikely(pkt->skb->nf_trace))
nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
jumpstack[stackptr].chain = chain;
jumpstack[stackptr].rule = rule;
jumpstack[stackptr].rulenum = rulenum;
stackptr++;
/* fall through */
case NFT_GOTO:
chain = data[NFT_REG_VERDICT].chain;
goto do_chain;
case NFT_RETURN:
if (unlikely(pkt->skb->nf_trace))
nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);
/* fall through */
case NFT_CONTINUE:
break;
default:
......@@ -147,13 +197,20 @@ nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
}
if (stackptr > 0) {
if (unlikely(pkt->skb->nf_trace))
nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);
stackptr--;
chain = jumpstack[stackptr].chain;
rule = jumpstack[stackptr].rule;
rulenum = jumpstack[stackptr].rulenum;
goto next_rule;
}
nft_chain_stats(chain, pkt, jumpstack, stackptr);
if (unlikely(pkt->skb->nf_trace))
nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY);
return nft_base_chain(chain)->policy;
}
EXPORT_SYMBOL_GPL(nft_do_chain_pktinfo);
......
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