From: Florian Westphal <f...@strlen.de>
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 <f...@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
.../netfilter/nf_conntrack_l3proto_ipv4_compat.c | 24 +++++++++++++++++-----
1 file 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 f0dfe92..483cf79 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));
--
2.1.4
