MFC r274246:

  Overhaul if_gre(4).

  Split it into two modules: if_gre(4) for GRE encapsulation and
  if_me(4) for minimal encapsulation within IP.

  gre(4) changes:
  * convert to if_transmit;
  * rework locking: protect access to softc with rmlock,
    protect from concurrent ioctls with sx lock;
  * correct interface accounting for outgoing datagramms (count only payload size);
  * implement generic support for using IPv6 as delivery header;
  * make implementation conform to the RFC 2784 and partially to RFC 2890;
  * add support for GRE checksums - calculate for outgoing datagramms and check
    for inconming datagramms;
  * add support for sending sequence number in GRE header;
  * remove support of cached routes. This fixes problem, when gre(4) doesn't
    work at system startup. But this also removes support for having tunnels with
    the same addresses for inner and outer header.
  * deprecate support for various GREXXX ioctls, that doesn't used in FreeBSD.
    Use our standard ioctls for tunnels.

  me(4):
  * implementation conform to RFC 2004;
  * use if_transmit;
  * use the same locking model as gre(4);

  PR:		164475

MFC r274289 (by bz):
  gcc requires variables to be initialised in two places.  One of them
  is correctly  used only under the same conditional though.

  For module builds properly check if the kernel supports INET or INET6,
  as otherwise various mips kernels without IPv6 support would fail to build.

MFC r274964:
  Add ip_gre.h to ObsoleteFiles.inc.

1 files changed, 85 insertions, 0 deletions

diff --git a/share/man/man4/me.4 b/share/man/man4/me.4
new file mode 100644
index 0000000..e1be5c8
--- /dev/null
+++ b/share/man/man4/me.4
@@ -0,0 +1,85 @@
+.\" Copyright (c) Andrey V. Elsukov <ae@FreeBSD.org>
+.\" All rights reserved.
+.\"
+.\" 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 AUTHORS 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 AUTHORS 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 7, 2014
+.Dt ME 4
+.Os
+.Sh NAME
+.Nm me
+.Nd encapsulating network device
+.Sh SYNOPSIS
+To compile the
+driver into the kernel, place the following line in the kernel
+configuration file:
+.Bd -ragged -offset indent
+.Cd "device me"
+.Ed
+.Pp
+Alternatively, to load the
+driver as a module at boot time, place the following line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+if_me_load="YES"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+network interface pseudo device encapsulates datagrams
+into IP.
+These encapsulated datagrams are routed to a destination host,
+where they are decapsulated and further routed to their final destination.
+.Pp
+.Nm
+interfaces are dynamically created and destroyed with the
+.Xr ifconfig 8
+.Cm create
+and
+.Cm destroy
+subcommands.
+.Pp
+This driver corresponds to RFC 2004.
+Datagrams are encapsulated into IP with a shorter encapsulation.
+The original
+IP header is modified and the modifications are inserted between the
+so modified header and the original payload.
+The protocol number 55 is used for outer header.
+.Sh NOTES
+.Pp
+For correct operation, the
+.Nm
+device needs a route to the decapsulating host that does not run over the tunnel,
+as this would be a loop.
+.Sh SEE ALSO
+.Xr gif 4 ,
+.Xr gre 4 ,
+.Xr inet 4 ,
+.Xr ip 4 ,
+.Xr netintro 4 ,
+.Xr protocols 5 ,
+.Xr ifconfig 8 ,
+.Xr sysctl 8
+.Sh AUTHORS
+.An Andrey V. Elsukov Aq Mt ae@FreeBSD.org