[PATCH net] mlxsw: spectrum_router: Fix IPv4 nexthop gateway indication

[Ido Schimmel <idosch@nvidia.com>]

mlxsw needs to distinguish nexthops with a gateway from connected
nexthops in order to write the former to the adjacency table of the
device. The check used to rely on the fact that nexthops with a gateway
have a 'link' scope whereas connected nexthops have a 'host' scope. This
is no longer correct after commit 747c14307214 ("ip: fix dflt addr
selection for connected nexthop").

Fix that by instead checking the address family of the gateway IP. This
is a more direct way and also consistent with the IPv6 counterpart in
mlxsw_sp_rt6_is_gateway().

Cc: stable@vger.kernel.org
Fixes: 747c14307214 ("ip: fix dflt addr selection for connected nexthop")
Fixes: 597cfe4fc339 ("nexthop: Add support for IPv4 nexthops")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Amit Cohen <amcohen@nvidia.com>
---
Copied stable since Nicolas' patch has stable copied and I don't want
stable trees to have his patch, but not mine. To make it clear how far
this patch needs to be backported, I have included the same Fixes tag as
him.
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 23d526f13f1c..abc0096a20a9 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -5292,7 +5292,7 @@ static bool mlxsw_sp_fi_is_gateway(const struct mlxsw_sp *mlxsw_sp,
 {
 	const struct fib_nh *nh = fib_info_nh(fi, 0);
 
-	return nh->fib_nh_scope == RT_SCOPE_LINK ||
+	return nh->fib_nh_gw_family ||
 	       mlxsw_sp_nexthop4_ipip_type(mlxsw_sp, nh, NULL);
 }
 
-- 
2.36.1