[PATCH net-next 08/11] netfilter: flowtable: check namespace before iterating flows

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Qingfang Deng <qingfang.deng@linux.dev>

nf_flow_table_cleanup() walks every registered flow table, checking the
network namespace for each flow in nf_flow_table_do_cleanup(). As a
result, tables in other namespaces are still iterated and their cleanup
work is flushed.

Compare the flow table's namespace with the device's namespace in
nf_flow_table_cleanup() and skip nonmatching tables. This avoids
unnecessary iteration and work flushing, and leaves the per-flow cleanup
callback to check only the interface index.

Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_core.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index 934c6151f558..bd8f9cf394ff 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -737,14 +737,9 @@ static void nf_flow_table_do_cleanup(struct nf_flowtable *flow_table,
 {
 	struct net_device *dev = data;
 
-	if (!dev) {
-		flow_offload_teardown(flow);
-		return;
-	}
-
-	if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
-	    (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
-	     flow->tuplehash[1].tuple.iifidx == dev->ifindex))
+	if (!dev ||
+	    flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
+	    flow->tuplehash[1].tuple.iifidx == dev->ifindex)
 		flow_offload_teardown(flow);
 }
 
@@ -761,8 +756,10 @@ void nf_flow_table_cleanup(struct net_device *dev)
 	struct nf_flowtable *flowtable;
 
 	mutex_lock(&flowtable_lock);
-	list_for_each_entry(flowtable, &flowtables, list)
-		nf_flow_table_gc_cleanup(flowtable, dev);
+	list_for_each_entry(flowtable, &flowtables, list) {
+		if (net_eq(read_pnet(&flowtable->net), dev_net(dev)))
+			nf_flow_table_gc_cleanup(flowtable, dev);
+	}
 	mutex_unlock(&flowtable_lock);
 }
 EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
-- 
2.47.3