From: Florian Westphal <fw@strlen.de>
To: <netfilter-devel@vger.kernel.org>
Cc: Florian Westphal <fw@strlen.de>
Subject: [PATCH nf 3/4] netfilter: conntrack: split resolve_clash function
Date: Mon, 3 Feb 2020 17:37:06 +0100 [thread overview]
Message-ID: <20200203163707.27254-4-fw@strlen.de> (raw)
In-Reply-To: <20200203163707.27254-1-fw@strlen.de>
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>
---
net/netfilter/nf_conntrack_core.c | 58 ++++++++++++++++++++++---------
1 file 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;
}
--
2.24.1
next prev parent reply other threads:[~2020-02-03 16:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 16:37 [PATCH nf 0/4] netfilter: conntrack: allow insertion of clashing entries Florian Westphal
2020-02-03 16:37 ` [PATCH nf 1/4] netfilter: conntrack: remove two args from resolve_clash Florian Westphal
2020-02-03 16:37 ` [PATCH nf 2/4] netfilter: conntrack: place confirm-bit setting in a helper Florian Westphal
2020-02-03 16:37 ` Florian Westphal [this message]
2020-02-03 16:37 ` [PATCH nf 4/4] netfilter: conntrack: allow insertion of clashing entries Florian Westphal
2020-02-17 19:25 ` [PATCH nf 0/4] " Pablo Neira Ayuso
2020-02-17 20:12 ` Florian Westphal
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