mlxsw: Add ECN configurations with IPinIP tunnels

Initialize ECN mapping registers during router init according to
INET_ECN_encapsulate() and INET_ECN_decapsulate().

For IP-in-IP encapsulation, this is required to ensure that ECN bits in
the underlay are set in accordance with the kernel. For decapsulation,
this is required to ensure that packets with invalid ECN combination in
underlay and overlay are trapped to the kernel and not forwarded.

Signed-off-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -3,8 +3,10 @@
 
 #include <net/ip_tunnels.h>
 #include <net/ip6_tunnel.h>
+#include <net/inet_ecn.h>
 
 #include "spectrum_ipip.h"
+#include "reg.h"
 
 struct ip_tunnel_parm
 mlxsw_sp_ipip_netdev_parms4(const struct net_device *ol_dev)
@@ -338,3 +340,61 @@ static const struct mlxsw_sp_ipip_ops mlxsw_sp_ipip_gre4_ops = {
 const struct mlxsw_sp_ipip_ops *mlxsw_sp_ipip_ops_arr[] = {
 	[MLXSW_SP_IPIP_TYPE_GRE4] = &mlxsw_sp_ipip_gre4_ops,
 };
+
+static int mlxsw_sp_ipip_ecn_encap_init_one(struct mlxsw_sp *mlxsw_sp,
+					    u8 inner_ecn, u8 outer_ecn)
+{
+	char tieem_pl[MLXSW_REG_TIEEM_LEN];
+
+	mlxsw_reg_tieem_pack(tieem_pl, inner_ecn, outer_ecn);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(tieem), tieem_pl);
+}
+
+int mlxsw_sp_ipip_ecn_encap_init(struct mlxsw_sp *mlxsw_sp)
+{
+	int i;
+
+	/* Iterate over inner ECN values */
+	for (i = INET_ECN_NOT_ECT; i <= INET_ECN_CE; i++) {
+		u8 outer_ecn = INET_ECN_encapsulate(0, i);
+		int err;
+
+		err = mlxsw_sp_ipip_ecn_encap_init_one(mlxsw_sp, i, outer_ecn);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int mlxsw_sp_ipip_ecn_decap_init_one(struct mlxsw_sp *mlxsw_sp,
+					    u8 inner_ecn, u8 outer_ecn)
+{
+	char tidem_pl[MLXSW_REG_TIDEM_LEN];
+	bool trap_en, set_ce = false;
+	u8 new_inner_ecn;
+
+	trap_en = __INET_ECN_decapsulate(outer_ecn, inner_ecn, &set_ce);
+	new_inner_ecn = set_ce ? INET_ECN_CE : inner_ecn;
+
+	mlxsw_reg_tidem_pack(tidem_pl, outer_ecn, inner_ecn, new_inner_ecn,
+			     trap_en, trap_en ? MLXSW_TRAP_ID_DECAP_ECN0 : 0);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(tidem), tidem_pl);
+}
+
+int mlxsw_sp_ipip_ecn_decap_init(struct mlxsw_sp *mlxsw_sp)
+{
+	int i, j, err;
+
+	/* Iterate over inner ECN values */
+	for (i = INET_ECN_NOT_ECT; i <= INET_ECN_CE; i++) {
+		/* Iterate over outer ECN values */
+		for (j = INET_ECN_NOT_ECT; j <= INET_ECN_CE; j++) {
+			err = mlxsw_sp_ipip_ecn_decap_init_one(mlxsw_sp, i, j);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}

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

@@ -7791,8 +7791,18 @@ mlxsw_sp_ipip_config_tigcr(struct mlxsw_sp *mlxsw_sp)
 
 static int mlxsw_sp_ipips_init(struct mlxsw_sp *mlxsw_sp)
 {
+	int err;
+
 	mlxsw_sp->router->ipip_ops_arr = mlxsw_sp_ipip_ops_arr;
 	INIT_LIST_HEAD(&mlxsw_sp->router->ipip_list);
+
+	err = mlxsw_sp_ipip_ecn_encap_init(mlxsw_sp);
+	if (err)
+		return err;
+	err = mlxsw_sp_ipip_ecn_decap_init(mlxsw_sp);
+	if (err)
+		return err;
+
 	return mlxsw_sp_ipip_config_tigcr(mlxsw_sp);
 }
 

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

@@ -104,4 +104,7 @@ static inline bool mlxsw_sp_l3addr_eq(const union mlxsw_sp_l3addr *addr1,
 	return !memcmp(addr1, addr2, sizeof(*addr1));
 }
 
+int mlxsw_sp_ipip_ecn_encap_init(struct mlxsw_sp *mlxsw_sp);
+int mlxsw_sp_ipip_ecn_decap_init(struct mlxsw_sp *mlxsw_sp);
+
 #endif /* _MLXSW_ROUTER_H_*/