[PATCH 11/24] man/man7/sock_diag.7: udiag_states: Document TCP_CLOSE

["Günther Noack" <gnoack3000@gmail.com>]

UNIX sockets can also be in the TCP_CLOSE state and it is possible to
query for that with sock_diag's udiag_states.  Document that in the
description of unix_diag_req (for querying) and unix_diag_msg (for the
response).

The implementaiton is in linux.git net/unix/diag.c, where
unix_diag_dump() filters on 'req->udiag_states & (1 << sk->sk_state)'.

Fixes: 4f6a0a4a (2016-12-07; "sock_diag.7: New page documenting NETLINK_SOCK_DIAG interface")
Assisted-by: LLM
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
---

Notes:
    The full list of "supported" states here is technically more of an
    implementation artifact -- the supported states are simply the states
    that a UNIX socket can assume.  So the kernel code does not explicitly
    check that anywhere, it's just documenting the states that can exist
    in practice.
    
    The initial LLM phrasing had added a section going into detail about
    the reasons why a socket might be in TCP_CLOSE state, but it felt like
    that was anyway obvious, and the phrasing was a bit vague in that it
    only gave an example.  I deleted that sentence and only kept the part
    that adds the mention of TCP_CLOSE.

 man/man7/sock_diag.7 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/man/man7/sock_diag.7 b/man/man7/sock_diag.7
index 8f8b28b4404d..20733cb8c8ae 100644
--- a/man/man7/sock_diag.7
+++ b/man/man7/sock_diag.7
@@ -151,6 +151,9 @@ Supported values are:
 .P
 1 <<
 .B TCP_LISTEN
+.P
+1 <<
+.B TCP_CLOSE
 .RE
 .TP
 .I udiag_ino
@@ -307,9 +310,10 @@ or
 .TP
 .I udiag_state
 This is set to one of
-.B TCP_LISTEN
+.BR TCP_LISTEN ,
+.BR TCP_ESTABLISHED ,
 or
-.BR TCP_ESTABLISHED .
+.BR TCP_CLOSE .
 .TP
 .I pad
 This field is set to 0.
-- 
2.56.0