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authorFlorian Westphal <fw@strlen.de>2020-02-03 17:37:06 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2020-02-11 11:45:01 +0100
commitbb89abe52bf426f1f40850c441efc77426cc31e1 (patch)
treec6a841107076513fec3aed4d84a1fd5c521a6fe8 /net/netfilter
parentb1b32552c1d81f0cf6a8e79043a2a47e769ff071 (diff)
netfilter: conntrack: split resolve_clash function
Followup patch will need a helper function with the 'clashing entries refer to the identical tuple in both directions' resolution logic. This patch will add another resolve_clash helper where loser_ct must not be added to the dying list because it will be inserted into the table. Therefore this also moves the stat counters and dying-list insertion of the losing ct. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nf_conntrack_core.c58
1 files changed, 41 insertions, 17 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 5fda5bd10160..3f069eb0f0fc 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -907,6 +907,39 @@ static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
tstamp->start = ktime_get_real_ns();
}
+static int __nf_ct_resolve_clash(struct sk_buff *skb,
+ struct nf_conntrack_tuple_hash *h)
+{
+ /* This is the conntrack entry already in hashes that won race. */
+ struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *loser_ct;
+
+ loser_ct = nf_ct_get(skb, &ctinfo);
+
+ if (nf_ct_is_dying(ct))
+ return NF_DROP;
+
+ if (!atomic_inc_not_zero(&ct->ct_general.use))
+ return NF_DROP;
+
+ if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
+ nf_ct_match(ct, loser_ct)) {
+ struct net *net = nf_ct_net(ct);
+
+ nf_ct_acct_merge(ct, ctinfo, loser_ct);
+ nf_ct_add_to_dying_list(loser_ct);
+ nf_conntrack_put(&loser_ct->ct_general);
+ nf_ct_set(skb, ct, ctinfo);
+
+ NF_CT_STAT_INC(net, insert_failed);
+ return NF_ACCEPT;
+ }
+
+ nf_ct_put(ct);
+ return NF_DROP;
+}
+
/**
* nf_ct_resolve_clash - attempt to handle clash without packet drop
*
@@ -941,31 +974,23 @@ nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h)
enum ip_conntrack_info ctinfo;
struct nf_conn *loser_ct;
struct net *net;
+ int ret;
loser_ct = nf_ct_get(skb, &ctinfo);
+ net = nf_ct_net(loser_ct);
l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
if (!l4proto->allow_clash)
goto drop;
- if (nf_ct_is_dying(ct))
- goto drop;
-
- if (!atomic_inc_not_zero(&ct->ct_general.use))
- goto drop;
-
- if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
- nf_ct_match(ct, loser_ct)) {
- nf_ct_acct_merge(ct, ctinfo, loser_ct);
- nf_conntrack_put(&loser_ct->ct_general);
- nf_ct_set(skb, ct, ctinfo);
- return NF_ACCEPT;
- }
+ ret = __nf_ct_resolve_clash(skb, h);
+ if (ret == NF_ACCEPT)
+ return ret;
- nf_ct_put(ct);
drop:
- net = nf_ct_net(loser_ct);
+ nf_ct_add_to_dying_list(loser_ct);
NF_CT_STAT_INC(net, drop);
+ NF_CT_STAT_INC(net, insert_failed);
return NF_DROP;
}
@@ -1034,6 +1059,7 @@ __nf_conntrack_confirm(struct sk_buff *skb)
if (unlikely(nf_ct_is_dying(ct))) {
nf_ct_add_to_dying_list(ct);
+ NF_CT_STAT_INC(net, insert_failed);
goto dying;
}
@@ -1075,11 +1101,9 @@ __nf_conntrack_confirm(struct sk_buff *skb)
return NF_ACCEPT;
out:
- nf_ct_add_to_dying_list(ct);
ret = nf_ct_resolve_clash(skb, h);
dying:
nf_conntrack_double_unlock(hash, reply_hash);
- NF_CT_STAT_INC(net, insert_failed);
local_bh_enable();
return ret;
}