netdev - [PATCH net-next 07/17] netfilter: flowtable: use tuple address to calculate next hop

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Message-ID: <20251128002345.29378-8-pablo@netfilter.org>
Date: Fri, 28 Nov 2025 00:23:34 +0000
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
	netdev@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	fw@...len.de,
	horms@...nel.org
Subject: [PATCH net-next 07/17] netfilter: flowtable: use tuple address to calculate next hop

This simplifies IPIP tunnel support coming in follow up patches.

No function changes are intended.

Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_flow_table_ip.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index ee6ec63257d1..083ceb64ac17 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -480,6 +480,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 {
 	struct flow_offload_tuple_rhash *tuplehash;
 	struct nf_flowtable *flow_table = priv;
+	struct flow_offload_tuple *other_tuple;
 	enum flow_offload_tuple_dir dir;
 	struct nf_flowtable_ctx ctx = {
 		.in	= state->in,
@@ -488,6 +489,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 	struct flow_offload *flow;
 	struct neighbour *neigh;
 	struct rtable *rt;
+	__be32 ip_daddr;
 	int ret;
 
 	tuplehash = nf_flow_offload_lookup(&ctx, flow_table, skb);
@@ -510,8 +512,10 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
+	other_tuple = &flow->tuplehash[!dir].tuple;
+	ip_daddr = other_tuple->src_v4.s_addr;
 
-	if (nf_flow_encap_push(skb, &flow->tuplehash[!dir].tuple) < 0)
+	if (nf_flow_encap_push(skb, other_tuple) < 0)
 		return NF_DROP;
 
 	switch (tuplehash->tuple.xmit_type) {
@@ -522,7 +526,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 			flow_offload_teardown(flow);
 			return NF_DROP;
 		}
-		neigh = ip_neigh_gw4(rt->dst.dev, rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr));
+		neigh = ip_neigh_gw4(rt->dst.dev, rt_nexthop(rt, ip_daddr));
 		if (IS_ERR(neigh)) {
 			flow_offload_teardown(flow);
 			return NF_DROP;
@@ -787,11 +791,13 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 {
 	struct flow_offload_tuple_rhash *tuplehash;
 	struct nf_flowtable *flow_table = priv;
+	struct flow_offload_tuple *other_tuple;
 	enum flow_offload_tuple_dir dir;
 	struct nf_flowtable_ctx ctx = {
 		.in	= state->in,
 	};
 	struct nf_flow_xmit xmit = {};
+	struct in6_addr *ip6_daddr;
 	struct flow_offload *flow;
 	struct neighbour *neigh;
 	struct rt6_info *rt;
@@ -817,8 +823,10 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
+	other_tuple = &flow->tuplehash[!dir].tuple;
+	ip6_daddr = &other_tuple->src_v6;
 
-	if (nf_flow_encap_push(skb, &flow->tuplehash[!dir].tuple) < 0)
+	if (nf_flow_encap_push(skb, other_tuple) < 0)
 		return NF_DROP;
 
 	switch (tuplehash->tuple.xmit_type) {
@@ -829,7 +837,7 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 			flow_offload_teardown(flow);
 			return NF_DROP;
 		}
-		neigh = ip_neigh_gw6(rt->dst.dev, rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6));
+		neigh = ip_neigh_gw6(rt->dst.dev, rt6_nexthop(rt, ip6_daddr));
 		if (IS_ERR(neigh)) {
 			flow_offload_teardown(flow);
 			return NF_DROP;
-- 
2.47.3