Since IPv4 routes support IPv6 gateways now, we can route IPv4 traffic in
NBMA tunnels.

Signed-off-by: Qing Deng <i@moy.cat>
---
 net/ipv6/ip6_tunnel.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index fe786df4f849..2bcffc3fc4ae 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1121,6 +1121,11 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 
 			memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
 			neigh_release(neigh);
+		} else if (skb->protocol == htons(ETH_P_IP)) {
+			struct rtable *rt = skb_rtable(skb);
+
+			if (rt->rt_gw_family == AF_INET6)
+				memcpy(&fl6->daddr, &rt->rt_gw6, sizeof(fl6->daddr));
 		}
 	} else if (t->parms.proto != 0 && !(t->parms.flags &
 					    (IP6_TNL_F_USE_ORIG_TCLASS |

base-commit: 1f40caa080474d0420e0b0e6c896e455acb6e236
-- 
2.32.0 (Apple Git-132)

On Sun, 23 Jan 2022 14:00:00 +0800 Qing Deng wrote:
> Since IPv4 routes support IPv6 gateways now, we can route IPv4 traffic in
> NBMA tunnels.
> 
> Signed-off-by: Qing Deng <i@moy.cat>

Applied, thanks, c1f55c5e0482 ("ip6_tunnel: allow routing IPv4 traffic
in NBMA mode")  in net-next.