Merge branch 'mlxsw-Add-layer-3-devlink-trap-support'

Ido Schimmel says:

====================
mlxsw: Add layer 3 devlink-trap support

This patch set from Amit adds support in mlxsw for layer 3 traps that
can report drops and exceptions via devlink-trap.

In a similar fashion to the existing layer 2 traps, these traps can send
packets to the CPU that were not routed as intended by the underlying
device.

The traps are divided between the two types detailed in devlink-trap
documentation: drops and exceptions. Unlike drops, packets received via
exception traps are also injected to the kernel's receive path, as they
are required for the correct functioning of the control plane. For
example, packets trapped due to TTL error must be injected to kernel's
receive path for traceroute to work properly.

Patch set overview:

Patch #1 adds the layer 3 drop traps to devlink along with their
documentation.

Patch #2 adds support for layer 3 drop traps in mlxsw.

Patches #3-#5 add selftests for layer 3 drop traps.

Patch #6 adds the layer 3 exception traps to devlink along with their
documentation.

Patches #7-#9 gradually add support for layer 3 exception traps in
mlxsw.

Patches #10-#12 add selftests for layer 3 exception traps.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/devlink-trap.rst

@@ -162,6 +162,67 @@ be added to the following table:
      - ``drop``
      - Traps packets that the device decided to drop because they could not be
        enqueued to a transmission queue which is full
+   * - ``non_ip``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to
+       undergo a layer 3 lookup, but are not IP or MPLS packets
+   * - ``uc_dip_over_mc_dmac``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and they have a unicast destination IP and a multicast destination
+       MAC
+   * - ``dip_is_loopback_address``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and their destination IP is the loopback address (i.e., 127.0.0.0/8
+       and ::1/128)
+   * - ``sip_is_mc``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and their source IP is multicast (i.e., 224.0.0.0/8 and ff::/8)
+   * - ``sip_is_loopback_address``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and their source IP is the loopback address (i.e., 127.0.0.0/8 and ::1/128)
+   * - ``ip_header_corrupted``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and their IP header is corrupted: wrong checksum, wrong IP version
+       or too short Internet Header Length (IHL)
+   * - ``ipv4_sip_is_limited_bc``
+     - ``drop``
+     - Traps packets that the device decided to drop because they need to be
+       routed and their source IP is limited broadcast (i.e., 255.255.255.255/32)
+   * - ``ipv6_mc_dip_reserved_scope``
+     - ``drop``
+     - Traps IPv6 packets that the device decided to drop because they need to
+       be routed and their IPv6 multicast destination IP has a reserved scope
+       (i.e., ffx0::/16)
+   * - ``ipv6_mc_dip_interface_local_scope``
+     - ``drop``
+     - Traps IPv6 packets that the device decided to drop because they need to
+       be routed and their IPv6 multicast destination IP has an interface-local scope
+       (i.e., ffx1::/16)
+   * - ``mtu_value_is_too_small``
+     - ``exception``
+     - Traps packets that should have been routed by the device, but were bigger
+       than the MTU of the egress interface
+   * - ``unresolved_neigh``
+     - ``exception``
+     - Traps packets that did not have a matching IP neighbour after routing
+   * - ``mc_reverse_path_forwarding``
+     - ``exception``
+     - Traps multicast IP packets that failed reverse-path forwarding (RPF)
+       check during multicast routing
+   * - ``reject_route``
+     - ``exception``
+     - Traps packets that hit reject routes (i.e., "unreachable", "prohibit")
+   * - ``ipv4_lpm_miss``
+     - ``exception``
+     - Traps unicast IPv4 packets that did not match any route
+   * - ``ipv6_lpm_miss``
+     - ``exception``
+     - Traps unicast IPv6 packets that did not match any route
 
 Driver-specific Packet Traps
 ============================

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

@@ -5480,6 +5480,7 @@ enum mlxsw_reg_htgt_trap_group {
 enum mlxsw_reg_htgt_discard_trap_group {
 	MLXSW_REG_HTGT_DISCARD_TRAP_GROUP_BASE = MLXSW_REG_HTGT_TRAP_GROUP_MAX,
 	MLXSW_REG_HTGT_TRAP_GROUP_SP_L2_DISCARDS,
+	MLXSW_REG_HTGT_TRAP_GROUP_SP_L3_DISCARDS,
 };
 
 /* reg_htgt_trap_group

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

@@ -4512,8 +4512,6 @@ static const struct mlxsw_listener mlxsw_sp_listener[] = {
 	MLXSW_SP_RXL_NO_MARK(IPV6_MLDV2_LISTENER_REPORT, TRAP_TO_CPU, IPV6_MLD,
 			     false),
 	/* L3 traps */
-	MLXSW_SP_RXL_MARK(MTUERROR, TRAP_TO_CPU, ROUTER_EXP, false),
-	MLXSW_SP_RXL_MARK(TTLERROR, TRAP_TO_CPU, ROUTER_EXP, false),
 	MLXSW_SP_RXL_L3_MARK(LBERROR, MIRROR_TO_CPU, LBERROR, false),
 	MLXSW_SP_RXL_MARK(IP2ME, TRAP_TO_CPU, IP2ME, false),
 	MLXSW_SP_RXL_MARK(IPV6_UNSPECIFIED_ADDRESS, TRAP_TO_CPU, ROUTER_EXP,
@@ -4540,8 +4538,6 @@ static const struct mlxsw_listener mlxsw_sp_listener[] = {
 	MLXSW_SP_RXL_MARK(L3_IPV6_REDIRECTION, TRAP_TO_CPU, IPV6_ND, false),
 	MLXSW_SP_RXL_MARK(IPV6_MC_LINK_LOCAL_DEST, TRAP_TO_CPU, ROUTER_EXP,
 			  false),
-	MLXSW_SP_RXL_MARK(HOST_MISS_IPV4, TRAP_TO_CPU, HOST_MISS, false),
-	MLXSW_SP_RXL_MARK(HOST_MISS_IPV6, TRAP_TO_CPU, HOST_MISS, false),
 	MLXSW_SP_RXL_MARK(ROUTER_ALERT_IPV4, TRAP_TO_CPU, ROUTER_EXP, false),
 	MLXSW_SP_RXL_MARK(ROUTER_ALERT_IPV6, TRAP_TO_CPU, ROUTER_EXP, false),
 	MLXSW_SP_RXL_MARK(IPIP_DECAP_ERROR, TRAP_TO_CPU, ROUTER_EXP, false),
@@ -4556,7 +4552,6 @@ static const struct mlxsw_listener mlxsw_sp_listener[] = {
 	/* Multicast Router Traps */
 	MLXSW_SP_RXL_MARK(IPV4_PIM, TRAP_TO_CPU, PIM, false),
 	MLXSW_SP_RXL_MARK(IPV6_PIM, TRAP_TO_CPU, PIM, false),
-	MLXSW_SP_RXL_MARK(RPF, TRAP_TO_CPU, RPF, false),
 	MLXSW_SP_RXL_MARK(ACL1, TRAP_TO_CPU, MULTICAST, false),
 	MLXSW_SP_RXL_L3_MARK(ACL2, TRAP_TO_CPU, MULTICAST, false),
 	/* NVE traps */

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

@@ -77,6 +77,7 @@ struct mlxsw_sp_router {
 	struct notifier_block inet6addr_nb;
 	const struct mlxsw_sp_rif_ops **rif_ops_arr;
 	const struct mlxsw_sp_ipip_ops **ipip_ops_arr;
+	u32 adj_discard_index;
 };
 
 struct mlxsw_sp_rif {
@@ -367,6 +368,7 @@ enum mlxsw_sp_fib_entry_type {
 	MLXSW_SP_FIB_ENTRY_TYPE_LOCAL,
 	MLXSW_SP_FIB_ENTRY_TYPE_TRAP,
 	MLXSW_SP_FIB_ENTRY_TYPE_BLACKHOLE,
+	MLXSW_SP_FIB_ENTRY_TYPE_UNREACHABLE,
 
 	/* This is a special case of local delivery, where a packet should be
 	 * decapsulated on reception. Note that there is no corresponding ENCAP,
@@ -4196,15 +4198,31 @@ mlxsw_sp_fib_entry_ralue_pack(char *ralue_pl,
 	}
 }
 
+static int mlxsw_sp_adj_discard_write(struct mlxsw_sp *mlxsw_sp, u16 rif_index)
+{
+	u32 adj_discard_index = mlxsw_sp->router->adj_discard_index;
+	enum mlxsw_reg_ratr_trap_action trap_action;
+	char ratr_pl[MLXSW_REG_RATR_LEN];
+
+	trap_action = MLXSW_REG_RATR_TRAP_ACTION_DISCARD_ERRORS;
+	mlxsw_reg_ratr_pack(ratr_pl, MLXSW_REG_RATR_OP_WRITE_WRITE_ENTRY, true,
+			    MLXSW_REG_RATR_TYPE_ETHERNET, adj_discard_index,
+			    rif_index);
+	mlxsw_reg_ratr_trap_action_set(ratr_pl, trap_action);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ratr), ratr_pl);
+}
+
 static int mlxsw_sp_fib_entry_op_remote(struct mlxsw_sp *mlxsw_sp,
 					struct mlxsw_sp_fib_entry *fib_entry,
 					enum mlxsw_reg_ralue_op op)
 {
+	struct mlxsw_sp_nexthop_group *nh_group = fib_entry->nh_group;
 	char ralue_pl[MLXSW_REG_RALUE_LEN];
 	enum mlxsw_reg_ralue_trap_action trap_action;
 	u16 trap_id = 0;
 	u32 adjacency_index = 0;
 	u16 ecmp_size = 0;
+	int err;
 
 	/* In case the nexthop group adjacency index is valid, use it
 	 * with provided ECMP size. Otherwise, setup trap and pass
@@ -4214,6 +4232,15 @@ static int mlxsw_sp_fib_entry_op_remote(struct mlxsw_sp *mlxsw_sp,
 		trap_action = MLXSW_REG_RALUE_TRAP_ACTION_NOP;
 		adjacency_index = fib_entry->nh_group->adj_index;
 		ecmp_size = fib_entry->nh_group->ecmp_size;
+	} else if (!nh_group->adj_index_valid && nh_group->count &&
+		   nh_group->nh_rif) {
+		err = mlxsw_sp_adj_discard_write(mlxsw_sp,
+						 nh_group->nh_rif->rif_index);
+		if (err)
+			return err;
+		trap_action = MLXSW_REG_RALUE_TRAP_ACTION_NOP;
+		adjacency_index = mlxsw_sp->router->adj_discard_index;
+		ecmp_size = 1;
 	} else {
 		trap_action = MLXSW_REG_RALUE_TRAP_ACTION_TRAP;
 		trap_id = MLXSW_TRAP_ID_RTR_INGRESS0;
@@ -4273,6 +4300,23 @@ static int mlxsw_sp_fib_entry_op_blackhole(struct mlxsw_sp *mlxsw_sp,
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
 }
 
+static int
+mlxsw_sp_fib_entry_op_unreachable(struct mlxsw_sp *mlxsw_sp,
+				  struct mlxsw_sp_fib_entry *fib_entry,
+				  enum mlxsw_reg_ralue_op op)
+{
+	enum mlxsw_reg_ralue_trap_action trap_action;
+	char ralue_pl[MLXSW_REG_RALUE_LEN];
+	u16 trap_id;
+
+	trap_action = MLXSW_REG_RALUE_TRAP_ACTION_TRAP;
+	trap_id = MLXSW_TRAP_ID_RTR_INGRESS1;
+
+	mlxsw_sp_fib_entry_ralue_pack(ralue_pl, fib_entry, op);
+	mlxsw_reg_ralue_act_local_pack(ralue_pl, trap_action, trap_id, 0);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
+}
+
 static int
 mlxsw_sp_fib_entry_op_ipip_decap(struct mlxsw_sp *mlxsw_sp,
 				 struct mlxsw_sp_fib_entry *fib_entry,
@@ -4314,6 +4358,9 @@ static int __mlxsw_sp_fib_entry_op(struct mlxsw_sp *mlxsw_sp,
 		return mlxsw_sp_fib_entry_op_trap(mlxsw_sp, fib_entry, op);
 	case MLXSW_SP_FIB_ENTRY_TYPE_BLACKHOLE:
 		return mlxsw_sp_fib_entry_op_blackhole(mlxsw_sp, fib_entry, op);
+	case MLXSW_SP_FIB_ENTRY_TYPE_UNREACHABLE:
+		return mlxsw_sp_fib_entry_op_unreachable(mlxsw_sp, fib_entry,
+							 op);
 	case MLXSW_SP_FIB_ENTRY_TYPE_IPIP_DECAP:
 		return mlxsw_sp_fib_entry_op_ipip_decap(mlxsw_sp,
 							fib_entry, op);
@@ -4391,7 +4438,7 @@ mlxsw_sp_fib4_entry_type_set(struct mlxsw_sp *mlxsw_sp,
 		 * can do so with a lower priority than packets directed
 		 * at the host, so use action type local instead of trap.
 		 */
-		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_LOCAL;
+		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_UNREACHABLE;
 		return 0;
 	case RTN_UNICAST:
 		if (mlxsw_sp_fi_is_gateway(mlxsw_sp, fi))
@@ -5351,7 +5398,7 @@ static void mlxsw_sp_fib6_entry_type_set(struct mlxsw_sp *mlxsw_sp,
 	else if (rt->fib6_type == RTN_BLACKHOLE)
 		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_BLACKHOLE;
 	else if (rt->fib6_flags & RTF_REJECT)
-		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_LOCAL;
+		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_UNREACHABLE;
 	else if (mlxsw_sp_rt6_is_gateway(mlxsw_sp, rt))
 		fib_entry->type = MLXSW_SP_FIB_ENTRY_TYPE_REMOTE;
 	else
@@ -8123,6 +8170,11 @@ int mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp,
 	if (err)
 		goto err_neigh_init;
 
+	err = mlxsw_sp_kvdl_alloc(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ, 1,
+				  &router->adj_discard_index);
+	if (err)
+		goto err_adj_discard_index_alloc;
+
 	mlxsw_sp->router->netevent_nb.notifier_call =
 		mlxsw_sp_router_netevent_event;
 	err = register_netevent_notifier(&mlxsw_sp->router->netevent_nb);
@@ -8151,6 +8203,9 @@ int mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp,
 err_mp_hash_init:
 	unregister_netevent_notifier(&mlxsw_sp->router->netevent_nb);
 err_register_netevent_notifier:
+	mlxsw_sp_kvdl_free(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ, 1,
+			   router->adj_discard_index);
+err_adj_discard_index_alloc:
 	mlxsw_sp_neigh_fini(mlxsw_sp);
 err_neigh_init:
 	mlxsw_sp_vrs_fini(mlxsw_sp);
@@ -8182,6 +8237,8 @@ void mlxsw_sp_router_fini(struct mlxsw_sp *mlxsw_sp)
 	unregister_fib_notifier(mlxsw_sp_net(mlxsw_sp),
 				&mlxsw_sp->router->fib_nb);
 	unregister_netevent_notifier(&mlxsw_sp->router->netevent_nb);
+	mlxsw_sp_kvdl_free(mlxsw_sp, MLXSW_SP_KVDL_ENTRY_TYPE_ADJ, 1,
+			   mlxsw_sp->router->adj_discard_index);
 	mlxsw_sp_neigh_fini(mlxsw_sp);
 	mlxsw_sp_vrs_fini(mlxsw_sp);
 	mlxsw_sp_mr_fini(mlxsw_sp);