netfilter: conntrack: document sctp timeouts

Exposed through sysctl, update documentation to describe sctp states and
their default timeouts.
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Documentation/networking/nf_conntrack-sysctl.rst

@@ -163,6 +163,39 @@ nf_conntrack_timestamp - BOOLEAN
 
 	Enable connection tracking flow timestamping.
 
+nf_conntrack_sctp_timeout_closed - INTEGER (seconds)
+	default 10
+
+nf_conntrack_sctp_timeout_cookie_wait - INTEGER (seconds)
+	default 3
+
+nf_conntrack_sctp_timeout_cookie_echoed - INTEGER (seconds)
+	default 3
+
+nf_conntrack_sctp_timeout_established - INTEGER (seconds)
+	default 432000 (5 days)
+
+nf_conntrack_sctp_timeout_shutdown_sent - INTEGER (seconds)
+	default 0.3
+
+nf_conntrack_sctp_timeout_shutdown_recd - INTEGER (seconds)
+	default 0.3
+
+nf_conntrack_sctp_timeout_shutdown_ack_sent - INTEGER (seconds)
+	default 3
+
+nf_conntrack_sctp_timeout_heartbeat_sent - INTEGER (seconds)
+	default 30
+
+	This timeout is used to setup conntrack entry on secondary paths.
+	Default is set to hb_interval.
+
+nf_conntrack_sctp_timeout_heartbeat_acked - INTEGER (seconds)
+	default 210
+
+	This timeout is used to setup conntrack entry on secondary paths.
+	Default is set to (hb_interval * path_max_retrans + rto_max)
+
 nf_conntrack_udp_timeout - INTEGER (seconds)
 	default 30