devlink: Create dedicated trap group for layer 3 exceptions

Packets that hit exceptions during layer 3 forwarding must be trapped to
the CPU for the control plane to function properly. Create a dedicated
group for them, so that user space could choose to assign a different
policer for them.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/devlink/devlink-trap.rst

@@ -277,8 +277,11 @@ narrow. The description of these groups must be added to the following table:
      - Contains packet traps for packets that were dropped by the device during
        layer 2 forwarding (i.e., bridge)
    * - ``l3_drops``
-     - Contains packet traps for packets that were dropped by the device or hit
-       an exception (e.g., TTL error) during layer 3 forwarding
+     - Contains packet traps for packets that were dropped by the device during
+       layer 3 forwarding
+   * - ``l3_exceptions``
+     - Contains packet traps for packets that hit an exception (e.g., TTL
+       error) during layer 3 forwarding
    * - ``buffer_drops``
      - Contains packet traps for packets that were dropped by the device due to
        an enqueue decision

include/net/devlink.h

@@ -657,6 +657,7 @@ enum devlink_trap_generic_id {
 enum devlink_trap_group_generic_id {
 	DEVLINK_TRAP_GROUP_GENERIC_ID_L2_DROPS,
 	DEVLINK_TRAP_GROUP_GENERIC_ID_L3_DROPS,
+	DEVLINK_TRAP_GROUP_GENERIC_ID_L3_EXCEPTIONS,
 	DEVLINK_TRAP_GROUP_GENERIC_ID_BUFFER_DROPS,
 	DEVLINK_TRAP_GROUP_GENERIC_ID_TUNNEL_DROPS,
 	DEVLINK_TRAP_GROUP_GENERIC_ID_ACL_DROPS,
@@ -730,6 +731,8 @@ enum devlink_trap_group_generic_id {
 	"l2_drops"
 #define DEVLINK_TRAP_GROUP_GENERIC_NAME_L3_DROPS \
 	"l3_drops"
+#define DEVLINK_TRAP_GROUP_GENERIC_NAME_L3_EXCEPTIONS \
+	"l3_exceptions"
 #define DEVLINK_TRAP_GROUP_GENERIC_NAME_BUFFER_DROPS \
 	"buffer_drops"
 #define DEVLINK_TRAP_GROUP_GENERIC_NAME_TUNNEL_DROPS \

net/core/devlink.c

@@ -8505,6 +8505,7 @@ static const struct devlink_trap devlink_trap_generic[] = {
 static const struct devlink_trap_group devlink_trap_group_generic[] = {
 	DEVLINK_TRAP_GROUP(L2_DROPS),
 	DEVLINK_TRAP_GROUP(L3_DROPS),
+	DEVLINK_TRAP_GROUP(L3_EXCEPTIONS),
 	DEVLINK_TRAP_GROUP(BUFFER_DROPS),
 	DEVLINK_TRAP_GROUP(TUNNEL_DROPS),
 	DEVLINK_TRAP_GROUP(ACL_DROPS),