From: Ido Schimmel <ido...@mellanox.com>

The device has a trap for IPv6 packets that need be routed and have a
unicast link-local destination IP (i.e., fe80::/10). This allows mlxsw
to ignore link-local routes, as the packets will be trapped to the CPU
in any case.

However, since link-local routes are not programmed, it is possible for
routed packets to hit the default route which might also be programmed
to trap packets. This means that packets with a link-local destination
IP might be trapped for the wrong reason.

To overcome this, allow programming link-local prefix routes (usually
one fe80::/64 per-table), so that the packets will be forwarded until
reaching the link-local trap.

Signed-off-by: Ido Schimmel <ido...@mellanox.com>
Reviewed-by: Jiri Pirko <j...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c 
b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 71aee4914619..c939b3596566 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -5003,9 +5003,11 @@ static bool mlxsw_sp_fib6_rt_should_ignore(const struct 
fib6_info *rt)
 {
        /* Packets with link-local destination IP arriving to the router
         * are trapped to the CPU, so no need to program specific routes
-        * for them.
+        * for them. Only allow prefix routes (usually one fe80::/64) so
+        * that packets are trapped for the right reason.
         */
-       if (ipv6_addr_type(&rt->fib6_dst.addr) & IPV6_ADDR_LINKLOCAL)
+       if ((ipv6_addr_type(&rt->fib6_dst.addr) & IPV6_ADDR_LINKLOCAL) &&
+           (rt->fib6_flags & (RTF_LOCAL | RTF_ANYCAST)))
                return true;
 
        /* Multicast routes aren't supported, so ignore them. Neighbour
-- 
2.26.2

Reply via email to