mlxsw: spectrum: Forward packets with an IPv4 link-local source IP

[ Upstream commit f604d3a ]

By default, the device does not forward IPv4 packets with a link-local
source IP (i.e., 169.254.0.0/16). This behavior does not align with the
kernel which does forward them.

Fix by instructing the device to forward such packets instead of
dropping them.

Fixes: ca360db ("mlxsw: spectrum: Disable DIP_LINK_LOCAL check in hardware pipeline")
Reported-by: Zoey Mertes <zoey@cloudflare.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://patch.msgid.link/6721e6b2c96feb80269e72ce8d0b426e2f32d99c.1755174341.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: idosch

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -2507,6 +2507,8 @@ static const struct mlxsw_listener mlxsw_sp_listener[] = {
 			     ROUTER_EXP, false),
 	MLXSW_SP_RXL_NO_MARK(DISCARD_ING_ROUTER_DIP_LINK_LOCAL, FORWARD,
 			     ROUTER_EXP, false),
+	MLXSW_SP_RXL_NO_MARK(DISCARD_ING_ROUTER_SIP_LINK_LOCAL, FORWARD,
+			     ROUTER_EXP, false),
 	/* Multicast Router Traps */
 	MLXSW_SP_RXL_MARK(ACL1, TRAP_TO_CPU, MULTICAST, false),
 	MLXSW_SP_RXL_L3_MARK(ACL2, TRAP_TO_CPU, MULTICAST, false),

drivers/net/ethernet/mellanox/mlxsw/trap.h

@@ -95,6 +95,7 @@ enum {
 	MLXSW_TRAP_ID_DISCARD_ING_ROUTER_IPV4_SIP_BC = 0x16A,
 	MLXSW_TRAP_ID_DISCARD_ING_ROUTER_IPV4_DIP_LOCAL_NET = 0x16B,
 	MLXSW_TRAP_ID_DISCARD_ING_ROUTER_DIP_LINK_LOCAL = 0x16C,
+	MLXSW_TRAP_ID_DISCARD_ING_ROUTER_SIP_LINK_LOCAL = 0x16D,
 	MLXSW_TRAP_ID_DISCARD_ROUTER_IRIF_EN = 0x178,
 	MLXSW_TRAP_ID_DISCARD_ROUTER_ERIF_EN = 0x179,
 	MLXSW_TRAP_ID_DISCARD_ROUTER_LPM4 = 0x17B,