[src/trunk]: src/share/man/man4 npflog.4: add a man page for the npflog device

[gutteridge <gutteridge%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d8c1be3344c5
branches:  trunk
changeset: 376480:d8c1be3344c5
user:      gutteridge <gutteridge%NetBSD.org@localhost>
date:      Tue Jun 20 01:02:46 2023 +0000

description:
npflog.4: add a man page for the npflog device

Addresses PR misc/57441 from Taylor R Campbell. (Not yet hooked into
source sets, will be done separately.)

(Borrows heavily from the equivalent pflog.4 man page already in tree,
and so retains the original copyright attribution as well.)

diffstat:

 share/man/man4/npflog.4 |  83 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 83 insertions(+), 0 deletions(-)

diffs (87 lines):

diff -r 6de827fa7c86 -r d8c1be3344c5 share/man/man4/npflog.4
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/share/man/man4/npflog.4   Tue Jun 20 01:02:46 2023 +0000
@@ -0,0 +1,83 @@
+.\" $NetBSD: npflog.4,v 1.1 2023/06/20 01:02:46 gutteridge Exp $
+.\"
+.\" Copyright (c) 2001 Tobias Weingartner
+.\" All rights reserved.
+.\"
+.\" Copyright (c) 2023 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" Portions of this documentation are derived from text contributed by
+.\" David H. Gutteridge.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd June 19, 2023
+.Dt NPFLOG 4
+.Os
+.Sh NAME
+.Nm npflog
+.Nd packet filter logging interface
+.Sh SYNOPSIS
+.Cd "pseudo-device npflog"
+.Sh DESCRIPTION
+The
+.Nm 
+interface is a pseudo-device which makes visible all packets logged by
+the
+.Xr npf 7
+packet filter.
+Logged packets can easily be monitored in real
+time by invoking
+.Xr tcpdump 8
+on the
+.Nm
+interface, or stored to disk using
+.Xr npfd 8 .
+.Pp
+The npflog0 interface is created automatically at boot if
+.Xr npf 7
+is enabled;
+further instances can be created using
+.Xr ifconfig 8 .
+.Pp
+Each packet retrieved on this interface has a header associated
+that presently matches the format used by
+.Xr pf 4 .
+However, this is intentionally not exposed to userland, and is also
+possibly subject to change in future.
+.Sh EXAMPLES
+Monitor all packets logged on the default interface:
+.Bd -literal -offset indent
+# tcpdump -n -e -tttt -i npflog0
+.Ed
+.Sh SEE ALSO
+.Xr inet 4 ,
+.Xr inet6 4 ,
+.Xr netintro 4 ,
+.Xr npf 7 ,
+.Xr ifconfig 8 ,
+.Xr npfd 8 ,
+.Xr tcpdump 8
+.Sh HISTORY
+The
+.Nm
+device first appeared in
+.Nx 6.0 .