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authorFlorian Westphal <fw@strlen.de>2016-04-28 19:13:44 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2016-05-05 16:39:45 +0200
commit245cfdcaba2e7e4ee16b12af547ead37f9c501cd (patch)
tree73bf9cd8574a8c9067c377c32e35f3493f956dce /net/ipv4
parent868043485ecb7cda503af0dfb9e2804e0260196a (diff)
netfilter: conntrack: small refactoring of conntrack seq_printf
The iteration process is lockless, so we test if the conntrack object is eligible for printing (e.g. is AF_INET) after obtaining the reference count. Once we put all conntracks into same hash table we might see more entries that need to be skipped. So add a helper and first perform the test in a lockless fashion for fast skip. Once we obtain the reference count, just repeat the check. Note that this refactoring also includes a missing check for unconfirmed conntrack entries due to slab rcu object re-usage, so they need to be skipped since they are not part of the listing. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
index f0dfe92a00d6..483cf7952e54 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
@@ -114,6 +114,19 @@ static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
}
#endif
+static bool ct_seq_should_skip(const struct nf_conn *ct,
+ const struct nf_conntrack_tuple_hash *hash)
+{
+ /* we only want to print DIR_ORIGINAL */
+ if (NF_CT_DIRECTION(hash))
+ return true;
+
+ if (nf_ct_l3num(ct) != AF_INET)
+ return true;
+
+ return false;
+}
+
static int ct_seq_show(struct seq_file *s, void *v)
{
struct nf_conntrack_tuple_hash *hash = v;
@@ -123,14 +136,15 @@ static int ct_seq_show(struct seq_file *s, void *v)
int ret = 0;
NF_CT_ASSERT(ct);
- if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
+ if (ct_seq_should_skip(ct, hash))
return 0;
+ if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
+ return 0;
- /* we only want to print DIR_ORIGINAL */
- if (NF_CT_DIRECTION(hash))
- goto release;
- if (nf_ct_l3num(ct) != AF_INET)
+ /* check if we raced w. object reuse */
+ if (!nf_ct_is_confirmed(ct) ||
+ ct_seq_should_skip(ct, hash))
goto release;
l3proto = __nf_ct_l3proto_find(nf_ct_l3num(ct));