Documentation/tcp-ao: Add a few lines on tracepoints

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/tcp_ao.rst

@@ -337,6 +337,15 @@ TCP-AO per-socket counters are also duplicated with per-netns counters,
 exposed with SNMP. Those are ``TCPAOGood``, ``TCPAOBad``, ``TCPAOKeyNotFound``,
 ``TCPAORequired`` and ``TCPAODroppedIcmps``.
 
+For monitoring purposes, there are following TCP-AO trace events:
+``tcp_hash_bad_header``, ``tcp_hash_ao_required``, ``tcp_ao_handshake_failure``,
+``tcp_ao_wrong_maclen``, ``tcp_ao_wrong_maclen``, ``tcp_ao_key_not_found``,
+``tcp_ao_rnext_request``, ``tcp_ao_synack_no_key``, ``tcp_ao_snd_sne_update``,
+``tcp_ao_rcv_sne_update``. It's possible to separately enable any of them and
+one can filter them by net-namespace, 4-tuple, family, L3 index, and TCP header
+flags. If a segment has a TCP-AO header, the filters may also include
+keyid, rnext, and maclen. SNE updates include the rolled-over numbers.
+
 RFC 5925 very permissively specifies how TCP port matching can be done for
 MKTs::