+pf_expose - INTEGER
+ Unset or enable/disable pf (pf is short for potentially failed) state
+ exposure. Applications can control the exposure of the PF path state
+ in the SCTP_PEER_ADDR_CHANGE event and the SCTP_GET_PEER_ADDR_INFO
+ sockopt. When it's unset, no SCTP_PEER_ADDR_CHANGE event with
+ SCTP_ADDR_PF state will be sent and a SCTP_PF-state transport info
+ can be got via SCTP_GET_PEER_ADDR_INFO sockopt; When it's enabled,
+ a SCTP_PEER_ADDR_CHANGE event will be sent for a transport becoming
+ SCTP_PF state and a SCTP_PF-state transport info can be got via
+ SCTP_GET_PEER_ADDR_INFO sockopt; When it's diabled, no
+ SCTP_PEER_ADDR_CHANGE event will be sent and it returns -EACCES when
+ trying to get a SCTP_PF-state transport info via SCTP_GET_PEER_ADDR_INFO
+ sockopt.
+
+ 0: Unset pf state exposure, Compatible with old applications.
+
+ 1: Disable pf state exposure.
+
+ 2: Enable pf state exposure.
+
+ Default: 0
+