Hi Lorenzo,
On Fri, Nov 07, 2025 at 12:14:47PM +0100, Lorenzo Bianconi wrote:
[...]
> @@ -565,8 +622,9 @@ 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;
>
> - if (nf_flow_encap_push(skb, &flow->tuplehash[!dir].tuple) < 0)
> + if (nf_flow_encap_push(state->net, skb, other_tuple))
> return NF_DROP;
>
> switch (tuplehash->tuple.xmit_type) {
> @@ -577,7 +635,9 @@ 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));
> + dest = other_tuple->tun_num ? other_tuple->tun.src_v4.s_addr
> + : other_tuple->src_v4.s_addr;
I think this can be simplified if my series use the ip_hdr(skb)->daddr
for rt_nexthop(), see attached patch. This would be fetched _before_
pushing the tunnel and layer 2 encapsulation headers. Then, there is
no need to fetch other_tuple and check if tun_num is greater than
zero.
See my sketch patch, I am going to give this a try, if this is
correct, I would need one more iteration from you.
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 8b74fb34998e..ff2b6c16c715 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -427,6 +427,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
struct flow_offload *flow;
struct neighbour *neigh;
struct rtable *rt;
+ __be32 ip_dst;
int ret;
tuplehash = nf_flow_offload_lookup(&ctx, flow_table, skb);
@@ -449,6 +450,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
+ ip_dst = ip_hdr(skb)->daddr;
switch (tuplehash->tuple.xmit_type) {
case FLOW_OFFLOAD_XMIT_NEIGH:
@@ -458,7 +460,7 @@ 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_dst));
if (IS_ERR(neigh)) {
flow_offload_teardown(flow);
return NF_DROP;
