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, 5 insertions, 2 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 8c1e789..f4993dd 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -867,12 +867,15 @@ device		tun
 #  The `gif' device implements IPv6 over IP4 tunneling,
 #  IPv4 over IPv6 tunneling, IPv4 over IPv4 tunneling and
 #  IPv6 over IPv6 tunneling.
-#  The `gre' device implements two types of IP4 over IP4 tunneling:
-#  GRE and MOBILE, as specified in the RFC1701 and RFC2004.
+#  The `gre' device implements GRE (Generic Routing Encapsulation) tunneling,
+#  as specified in the RFC 2784 and RFC 2890.
+#  The `me' device implements Minimal Encapsulation within IPv4 as
+#  specified in the RFC 2004.
 #  The XBONEHACK option allows the same pair of addresses to be configured on
 #  multiple gif interfaces.
 device		gif
 device		gre
+device		me
 options 	XBONEHACK
 
 #  The `faith' device captures packets sent to it and diverts them