From 2344d64ec71661f7201082cf727a7154f662e249 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 25 Aug 2016 15:33:32 +0200 Subject: [PATCH] netfilter: evict stale entries on netlink dumps When dumping we already have to look at the entire table, so we might as well toss those entries whose timeout value is in the past. We also look at every entry during resize operations. However, eviction there is not as simple because we hold the global resize lock so we can't evict without adding a 'expired' list to drop from later. Considering that resizes are very rare it doesn't seem worth doing it. Signed-off-by: Florian Westphal Acked-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 81fd34ce0a57..dedbe4b33f38 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -815,14 +815,23 @@ ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb) struct hlist_nulls_node *n; struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh); u_int8_t l3proto = nfmsg->nfgen_family; - int res; + struct nf_conn *nf_ct_evict[8]; + int res, i; spinlock_t *lockp; last = (struct nf_conn *)cb->args[1]; + i = 0; local_bh_disable(); for (; cb->args[0] < nf_conntrack_htable_size; cb->args[0]++) { restart: + while (i) { + i--; + if (nf_ct_should_gc(nf_ct_evict[i])) + nf_ct_kill(nf_ct_evict[i]); + nf_ct_put(nf_ct_evict[i]); + } + lockp = &nf_conntrack_locks[cb->args[0] % CONNTRACK_LOCKS]; nf_conntrack_lock(lockp); if (cb->args[0] >= nf_conntrack_htable_size) { @@ -834,6 +843,13 @@ ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb) if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL) continue; ct = nf_ct_tuplehash_to_ctrack(h); + if (nf_ct_is_expired(ct)) { + if (i < ARRAY_SIZE(nf_ct_evict) && + atomic_inc_not_zero(&ct->ct_general.use)) + nf_ct_evict[i++] = ct; + continue; + } + if (!net_eq(net, nf_ct_net(ct))) continue; @@ -875,6 +891,13 @@ ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb) if (last) nf_ct_put(last); + while (i) { + i--; + if (nf_ct_should_gc(nf_ct_evict[i])) + nf_ct_kill(nf_ct_evict[i]); + nf_ct_put(nf_ct_evict[i]); + } + return skb->len; }