documentation: networking: devlink: add prestera switched driver Documentation

Add documentation for the devlink feature prestera switchdev driver supports:
add description for the support of the driver-specific devlink traps
(include both traps with action TRAP and action DROP);
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/devlink/prestera.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+prestera devlink support
+=====================
+
+This document describes the devlink features implemented by the ``prestera``
+device driver.
+
+Driver-specific Traps
+=====================
+
+.. list-table:: List of Driver-specific Traps Registered by ``prestera``
+   :widths: 5 5 90
+
+   * - Name
+     - Type
+     - Description
+.. list-table:: List of Driver-specific Traps Registered by ``prestera``
+   :widths: 5 5 90
+
+   * - Name
+     - Type
+     - Description
+   * - ``arp_bc``
+     - ``trap``
+     - Traps ARP broadcast packets (both requests/responses)
+   * - ``is_is``
+     - ``trap``
+     - Traps IS-IS packets
+   * - ``ospf``
+     - ``trap``
+     - Traps OSPF packets
+   * - ``ip_bc_mac``
+     - ``trap``
+     - Traps IPv4 packets with broadcast DA Mac address
+   * - ``stp``
+     - ``trap``
+     - Traps STP BPDU
+   * - ``lacp``
+     - ``trap``
+     - Traps LACP packets
+   * - ``lldp``
+     - ``trap``
+     - Traps LLDP packets
+   * - ``router_mc``
+     - ``trap``
+     - Traps multicast packets
+   * - ``vrrp``
+     - ``trap``
+     - Traps VRRP packets
+   * - ``dhcp``
+     - ``trap``
+     - Traps DHCP packets
+   * - ``mtu_error``
+     - ``trap``
+     - Traps (exception) packets that exceeded port's MTU
+   * - ``mac_to_me``
+     - ``trap``
+     -  Traps packets with switch-port's DA Mac address
+   * - ``ttl_error``
+     - ``trap``
+     - Traps (exception) IPv4 packets whose TTL exceeded
+   * - ``ipv4_options``
+     - ``trap``
+     - Traps (exception) packets due to the malformed IPV4 header options
+   * - ``ip_default_route``
+     - ``trap``
+     - Traps packets that have no specific IP interface (IP to me) and no forwarding prefix
+   * - ``local_route``
+     - ``trap``
+     - Traps packets that have been send to one of switch IP interfaces addresses
+   * - ``ipv4_icmp_redirect``
+     - ``trap``
+     - Traps (exception) IPV4 ICMP redirect packets
+   * - ``arp_response``
+     - ``trap``
+     - Traps ARP replies packets that have switch-port's DA Mac address
+   * - ``acl_code_0``
+     - ``trap``
+     - Traps packets that have ACL priority set to 0 (tc pref 0)
+   * - ``acl_code_1``
+     - ``trap``
+     - Traps packets that have ACL priority set to 1 (tc pref 1)
+   * - ``acl_code_2``
+     - ``trap``
+     - Traps packets that have ACL priority set to 2 (tc pref 2)
+   * - ``acl_code_3``
+     - ``trap``
+     - Traps packets that have ACL priority set to 3 (tc pref 3)
+   * - ``acl_code_4``
+     - ``trap``
+     - Traps packets that have ACL priority set to 4 (tc pref 4)
+   * - ``acl_code_5``
+     - ``trap``
+     - Traps packets that have ACL priority set to 5 (tc pref 5)
+   * - ``acl_code_6``
+     - ``trap``
+     - Traps packets that have ACL priority set to 6 (tc pref 6)
+   * - ``acl_code_7``
+     - ``trap``
+     - Traps packets that have ACL priority set to 7 (tc pref 7)
+   * - ``ipv4_bgp``
+     - ``trap``
+     - Traps IPv4 BGP packets
+   * - ``ssh``
+     - ``trap``
+     - Traps SSH packets
+   * - ``telnet``
+     - ``trap``
+     - Traps Telnet packets
+   * - ``icmp``
+     - ``trap``
+     - Traps ICMP packets
+   * - ``rxdma_drop``
+     - ``drop``
+     - Drops packets (RxDMA) due to the lack of ingress buffers etc.
+   * - ``port_no_vlan``
+     - ``drop``
+     - Drops packets due to faulty-configured network or due to internal bug (config issue).
+   * - ``local_port``
+     - ``drop``
+     - Drops packets whose decision (FDB entry) is to bridge packet back to the incoming port/trunk.
+   * - ``invalid_sa``
+     - ``drop``
+     - Drops packets with multicast source MAC address.
+   * - ``illegal_ip_addr``
+     - ``drop``
+     - Drops packets with illegal SIP/DIP multicast/unicast addresses.
+   * - ``illegal_ipv4_hdr``
+     - ``drop``
+     - Drops packets with illegal IPV4 header.
+   * - ``ip_uc_dip_da_mismatch``
+     - ``drop``
+     - Drops packets with destination MAC being unicast, but destination IP address being multicast.
+   * - ``ip_sip_is_zero``
+     - ``drop``
+     - Drops packets with zero (0) IPV4 source address.
+   * - ``met_red``
+     - ``drop``
+     - Drops non-conforming packets (dropped by Ingress policer, metering drop), e.g. packet rate exceeded configured bandwith.