From b5bc89bfa0b46de37754610f46c0ef4e2280edb4 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 10 Oct 2013 16:49:19 +0200 Subject: [PATCH] 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: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 2 ++ net/netfilter/nf_tables_api.c | 1 + net/netfilter/nf_tables_core.c | 57 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 975ad3c..54c4a5c 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -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; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 79e1418..dcddc49 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -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) && diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index d581ef6..cb9e685 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -19,6 +19,7 @@ #include #include #include +#include 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 @@ next_rule: 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 @@ next_rule: 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 @@ next_rule: } 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); -- 2.7.4