From 04dac0111da7e1d284952cd415162451ffaa094d Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 27 Nov 2012 21:30:52 +0100 Subject: [PATCH] netfilter: nf_conntrack: improve nf_conn object traceability This patch modifies the conntrack subsystem so that all existing allocated conntrack objects can be found in any of the following places: * the hash table, this is the typical place for alive conntrack objects. * the unconfirmed list, this is the place for newly created conntrack objects that are still traversing the stack. * the dying list, this is where you can find conntrack objects that are dying or that should die anytime soon (eg. once the destroy event is delivered to the conntrackd daemon). Thus, we make sure that we follow the track for all existing conntrack objects. This patch, together with some extension of the ctnetlink interface to dump the content of the dying and unconfirmed lists, will help in case to debug suspected nf_conn object leaks. Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack.h | 2 +- net/netfilter/nf_conntrack_core.c | 25 +++++++++---------------- net/netfilter/nf_conntrack_netlink.c | 2 +- 3 files changed, 11 insertions(+), 18 deletions(-) diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index f1494feba79f..caca0c4d6b4b 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -182,7 +182,7 @@ __nf_conntrack_find(struct net *net, u16 zone, extern int nf_conntrack_hash_check_insert(struct nf_conn *ct); extern void nf_ct_delete_from_lists(struct nf_conn *ct); -extern void nf_ct_insert_dying_list(struct nf_conn *ct); +extern void nf_ct_dying_timeout(struct nf_conn *ct); extern void nf_conntrack_flush_report(struct net *net, u32 pid, int report); diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 0f241be28f9e..af175166fffa 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -221,11 +221,9 @@ destroy_conntrack(struct nf_conntrack *nfct) * too. */ nf_ct_remove_expectations(ct); - /* We overload first tuple to link into unconfirmed list. */ - if (!nf_ct_is_confirmed(ct)) { - BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); - hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); - } + /* We overload first tuple to link into unconfirmed or dying list.*/ + BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); + hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); NF_CT_STAT_INC(net, delete); spin_unlock_bh(&nf_conntrack_lock); @@ -247,6 +245,9 @@ void nf_ct_delete_from_lists(struct nf_conn *ct) * Otherwise we can get spurious warnings. */ NF_CT_STAT_INC(net, delete_list); clean_from_lists(ct); + /* add this conntrack to the dying list */ + hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, + &net->ct.dying); spin_unlock_bh(&nf_conntrack_lock); } EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); @@ -268,31 +269,23 @@ static void death_by_event(unsigned long ul_conntrack) } /* we've got the event delivered, now it's dying */ set_bit(IPS_DYING_BIT, &ct->status); - spin_lock(&nf_conntrack_lock); - hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); - spin_unlock(&nf_conntrack_lock); nf_ct_put(ct); } -void nf_ct_insert_dying_list(struct nf_conn *ct) +void nf_ct_dying_timeout(struct nf_conn *ct) { struct net *net = nf_ct_net(ct); struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); BUG_ON(ecache == NULL); - /* add this conntrack to the dying list */ - spin_lock_bh(&nf_conntrack_lock); - hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, - &net->ct.dying); - spin_unlock_bh(&nf_conntrack_lock); /* set a new timer to retry event delivery */ setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct); ecache->timeout.expires = jiffies + (random32() % net->ct.sysctl_events_retry_timeout); add_timer(&ecache->timeout); } -EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); +EXPORT_SYMBOL_GPL(nf_ct_dying_timeout); static void death_by_timeout(unsigned long ul_conntrack) { @@ -307,7 +300,7 @@ static void death_by_timeout(unsigned long ul_conntrack) unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { /* destroy event was not delivered */ nf_ct_delete_from_lists(ct); - nf_ct_insert_dying_list(ct); + nf_ct_dying_timeout(ct); return; } set_bit(IPS_DYING_BIT, &ct->status); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 7bbfb3deea30..34370a928360 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -989,7 +989,7 @@ ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb, nlmsg_report(nlh)) < 0) { nf_ct_delete_from_lists(ct); /* we failed to report the event, try later */ - nf_ct_insert_dying_list(ct); + nf_ct_dying_timeout(ct); nf_ct_put(ct); return 0; } -- 2.30.2