wlan_gcmp.4: add man page

The man page is heavily based on wlan_ccmp.4 with minor modifications
for GCMP.

Add the .Xr to the other wlan*.4 man pages.

Sposnored by:	The FreeBSD Foundation
MFC after:	3 days
Reviewed by:	adrian, ziaee
Differential Revision: https://reviews.freebsd.org/D50789

share/man/man4/wlan.4

@@ -192,6 +192,7 @@ Stations implementing earlier drafts (e.g., Linux) may be incompatible.
 .Xr urtw 4 ,
 .Xr wlan_acl 4 ,
 .Xr wlan_ccmp 4 ,
+.Xr wlan_gcmp 4 ,
 .Xr wlan_tkip 4 ,
 .Xr wlan_wep 4 ,
 .Xr wlan_xauth 4 ,

share/man/man4/wlan_ccmp.4

@@ -53,6 +53,7 @@ calculations in hardware, the
 module will do the work.
 .Sh SEE ALSO
 .Xr wlan 4 ,
+.Xr wlan_gcmp 4 ,
 .Xr wlan_tkip 4 ,
 .Xr wlan_wep 4
 .Sh STANDARDS

share/man/man4/wlan_gcmp.4

@@ -0,0 +1,72 @@
+.\"
+.\" Copyright (c) 2004 Sam Leffler
+.\" All rights reserved.
+.\" Copyright (c) 2025 The FreeBSD Foundation
+.\"
+.\" Portions of this documentation were written by Bj\xc3\xb6rn Zeeb
+.\" under sponsorship from the FreeBSD Foundation.
+.\"
+.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
+.\"
+.\" Based on wlan_ccmp.4.
+.\"
+.Dd June 13, 2025
+.Dt WLAN_GCMP 4
+.Os
+.Sh NAME
+.Nm wlan_gcmp
+.Nd AES-GCMP crypto support for 802.11 devices
+.Sh SYNOPSIS
+.Cd "device wlan_gcmp"
+.Sh DESCRIPTION
+The
+.Nm
+module handles the
+.Em Galois/Counter Mode Protocol
+cryptographic requirements of the IEEE 802.11ad and WPA2/WPA3 protocols.
+It does encapsulation and decapsulation of GCMP-encoded 802.11 frames
+and optionally calculates the AES-GCMP cipher.
+The
+.Nm
+module is an 802.11 cryptographic plugin module for use by the
+.Xr wlan 4
+module.
+This module is automatically loaded if an AES-GCMP key is configured;
+typically by a WPA supplicant program such as wpa_supplicant,
+or a WPA authenticator program such as
+.Nm hostapd .
+Should the underlying network device not be capable of doing the AES-GCMP
+calculations in hardware, the
+.Nm
+module will do the work.
+.Sh SEE ALSO
+.Xr wlan 4 ,
+.Xr wlan_ccmp 4 ,
+.Xr wlan_tkip 4 ,
+.Xr wlan_wep 4
+.Sh STANDARDS
+More information can be found in the IEEE 802.11, and WPA Standards.
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Fx 15.0 .

share/man/man4/wlan_tkip.4

@@ -54,6 +54,7 @@ module will do the work.
 .Sh SEE ALSO
 .Xr wlan 4 ,
 .Xr wlan_ccmp 4 ,
+.Xr wlan_gcmp 4 ,
 .Xr wlan_wep 4
 .Sh STANDARDS
 More information can be found in the IEEE 802.11, WPA, and 802.11i Standards.

share/man/man4/wlan_wep.4

@@ -51,6 +51,7 @@ module will do the work.
 .Sh SEE ALSO
 .Xr wlan 4 ,
 .Xr wlan_ccmp 4 ,
+.Xr wlan_gcmp 4 ,
 .Xr wlan_tkip 4
 .Sh STANDARDS
 More information can be found in the IEEE 802.11 Standard.