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, 22 insertions, 200 deletions

diff --git a/share/man/man4/gre.4 b/share/man/man4/gre.4
index da33fd3..6652bdf 100644
--- a/share/man/man4/gre.4
+++ b/share/man/man4/gre.4
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 20, 2008
+.Dd November 7, 2014
 .Dt GRE 4
 .Os
 .Sh NAME
@@ -68,163 +68,30 @@ and
 .Cm destroy
 subcommands.
 .Pp
-This driver currently supports the following modes of operation:
-.Bl -tag -width indent
-.It "GRE encapsulation (IP protocol number 47)"
-Encapsulated datagrams are
-prepended an outer datagram and a GRE header.
+This driver corresponds to RFC 2784.
+Encapsulated datagrams are prepended an outer datagram and a GRE header.
 The GRE header specifies
 the type of the encapsulated datagram and thus allows for tunneling other
 protocols than IP like e.g.\& AppleTalk.
 GRE mode is also the default tunnel mode on Cisco routers.
-This is also the default mode of operation of the
-.Nm
-interfaces.
-As part of the GRE mode,
 .Nm
 also supports Cisco WCCP protocol, both version 1 and version 2.
-Since there is no reliable way to distinguish between WCCP versions, it
-should be configured manually using the
-.Cm link2
-flag.
-If the
-.Cm link2
-flag is not set (default), then WCCP version 1 is selected.
-.It "MOBILE encapsulation (IP protocol number 55)"
-Datagrams are
-encapsulated into IP, but with a shorter encapsulation.
-The original
-IP header is modified and the modifications are inserted between the
-so modified header and the original payload.
-Like
-.Xr gif 4 ,
-only for IP-in-IP encapsulation.
-.El
 .Pp
 The
 .Nm
-interfaces support a number of
-.Xr ioctl 2 Ns s ,
-such as:
-.Bl -tag -width ".Dv GRESADDRS"
-.It Dv GRESADDRS
-Set the IP address of the local tunnel end.
-This is the source address
-set by or displayed by
-.Xr ifconfig 8
-for the
-.Nm
-interface.
-.It Dv GRESADDRD
-Set the IP address of the remote tunnel end.
-This is the destination address
-set by or displayed by
-.Xr ifconfig 8
-for the
-.Nm
-interface.
-.It Dv GREGADDRS
-Query the IP address that is set for the local tunnel end.
-This is the
-address the encapsulation header carries as local address (i.e., the real
-address of the tunnel start point).
-.It Dv GREGADDRD
-Query the IP address that is set for the remote tunnel end.
-This is the
-address the encapsulated packets are sent to (i.e., the real address of
-the remote tunnel endpoint).
-.It Dv GRESPROTO
-Set the operation mode to the specified IP protocol value.
-The
-protocol is passed to the interface in
-.Po Vt "struct ifreq" Pc Ns Li -> Ns Va ifr_flags .
-The operation mode can also be given as
-.Pp
-.Bl -tag -width ".Cm -link0" -compact
-.It Cm link0
-.Dv IPPROTO_GRE
-.It Cm -link0
-.Dv IPPROTO_MOBILE
-.El
-.Pp
-to
-.Xr ifconfig 8 .
-.Pp
-The
-.Cm link1
-flag is not used to choose encapsulation, but to modify the
-internal route search for the remote tunnel endpoint, see the
-.Sx BUGS
-section below.
-.It Dv GREGPROTO
-Query operation mode.
-.It Dv GRESKEY
+interfaces support a number of additional parameters to the
+.Xr ifconfig 8 :
+.Bl -tag -width "enable_csum"
+.It Ar grekey
 Set the GRE key used for outgoing packets.
 A value of 0 disables the key option.
-.It Dv GREGKEY
-Get the GRE key currently used for outgoing packets.
-0 means no outgoing key.
+.It Ar enable_csum
+Enables checksum calculation for outgoing packets.
+.It Ar enable_seq
+Enables use of sequence number field in the GRE header for outgoing packets.
 .El
-.Pp
-Note that the IP addresses of the tunnel endpoints may be the same as the
-ones defined with
-.Xr ifconfig 8
-for the interface (as if IP is encapsulated), but need not be, as e.g.\& when
-encapsulating AppleTalk.
 .Sh EXAMPLES
-Configuration example:
-.Bd -literal
-Host X-- Host A  ----------------tunnel---------- Cisco D------Host E
-          \\                                          |
-           \\                                        /
-            +------Host B----------Host C----------+
-.Ed
 .Pp
-On host A
-.Pq Fx :
-.Bd -literal -offset indent
-route add default B
-ifconfig greN create
-ifconfig greN A D netmask 0xffffffff linkX up
-ifconfig greN tunnel A D
-route add E D
-.Ed
-.Pp
-On Host D (Cisco):
-.Bd -literal -offset indent
-Interface TunnelX
- ip unnumbered D   ! e.g. address from Ethernet interface
- tunnel source D   ! e.g. address from Ethernet interface
- tunnel destination A
-ip route C <some interface and mask>
-ip route A mask C
-ip route X mask tunnelX
-.Ed
-.Pp
-OR
-.Pp
-On Host D
-.Pq Fx :
-.Bd -literal -offset indent
-route add default C
-ifconfig greN create
-ifconfig greN D A
-ifconfig greN tunnel D A
-.Ed
-.Pp
-If all goes well, you should see packets flowing ;-)
-.Pp
-If you want to reach Host A over the tunnel (from Host D (Cisco)), then
-you have to have an alias on Host A for e.g.\& the Ethernet interface like:
-.Pp
-.Dl "ifconfig <etherif> alias Y"
-.Pp
-and on the Cisco:
-.Pp
-.Dl "ip route Y mask tunnelX"
-.Pp
-A similar setup can be used to create a link between two private networks
-(for example in the 192.168 subnet) over the Internet:
 .Bd -literal
 192.168.1.* --- Router A  -------tunnel-------- Router B --- 192.168.2.*
                    \\                              /
@@ -239,29 +106,22 @@ Assuming router A has the (external) IP address A and the internal address
 On router A:
 .Bd -literal -offset indent
 ifconfig greN create
-ifconfig greN 192.168.1.1 192.168.2.1 link1
-ifconfig greN tunnel A B
+ifconfig greN inet 192.168.1.1 192.168.2.1
+ifconfig greN inet tunnel A B
 route add -net 192.168.2 -netmask 255.255.255.0 192.168.2.1
 .Ed
 .Pp
 On router B:
 .Bd -literal -offset indent
 ifconfig greN create
-ifconfig greN 192.168.2.1 192.168.1.1 link1
-ifconfig greN tunnel B A
+ifconfig greN inet 192.168.2.1 192.168.1.1
+ifconfig greN inet tunnel B A
 route add -net 192.168.1 -netmask 255.255.255.0 192.168.1.1
 .Ed
-.Pp
-Note that this is a safe situation where the
-.Cm link1
-flag (as discussed in the
-.Sx BUGS
-section below) may (and probably should) be set.
 .Sh NOTES
 The MTU of
 .Nm
 interfaces is set to 1476 by default, to match the value used by Cisco routers.
-If grekey is set this is lowered to 1472.
 This may not be an optimal value, depending on the link between the two tunnel
 endpoints.
 It can be adjusted via
@@ -269,25 +129,8 @@ It can be adjusted via
 .Pp
 For correct operation, the
 .Nm
-device needs a route to the destination that is less specific than the
-one over the tunnel.
-(Basically, there needs to be a route to the decapsulating host that
-does not run over the tunnel, as this would be a loop.)
-If the addresses are ambiguous, doing the
-.Nm ifconfig Cm tunnel
-step before the
-.Xr ifconfig 8
-call to set the
-.Nm
-IP addresses will help to find a route outside the tunnel.
-.Pp
-In order to tell
-.Xr ifconfig 8
-to actually mark the interface as
-.Dq up ,
-the keyword
-.Cm up
-must be given last on its command line.
+device needs a route to the decapsulating host that does not run over the tunnel,
+as this would be a loop.
 .Pp
 The kernel must be set to forward datagrams by setting the
 .Va net.inet.ip.forwarding
@@ -298,41 +141,20 @@ variable to non-zero.
 .Xr gif 4 ,
 .Xr inet 4 ,
 .Xr ip 4 ,
+.Xr me 4 ,
 .Xr netintro 4 ,
-.\" Xr options 4 ,
 .Xr protocols 5 ,
 .Xr ifconfig 8 ,
 .Xr sysctl 8
 .Pp
-A description of GRE encapsulation can be found in RFC 1701 and RFC 1702.
-.Pp
-A description of MOBILE encapsulation can be found in RFC 2004.
+A description of GRE encapsulation can be found in RFC 2784 and RFC 2890.
 .Sh AUTHORS
-.An Heiko W.Rupp Aq hwr@pilhuhn.de
+.An Andrey V. Elsukov Aq Mt ae@FreeBSD.org
+.An Heiko W.Rupp Aq Mt hwr@pilhuhn.de
 .Sh BUGS
-The
-.Fn compute_route
-code in
-.Pa if_gre.c
-toggles the last bit of the
-IP-address to provoke the search for a less specific route than the
-one directly over the tunnel to prevent loops.
-This is possibly not the best solution.
-.Pp
-To avoid the address munging described above, turn on the
-.Cm link1
-flag on the
-.Xr ifconfig 8
-command line.
-This implies that the GRE packet destination and the ifconfig remote host
-are not the same IP addresses, and that the GRE destination does not route
-over the
-.Nm
-interface itself.
 .Pp
 The current implementation uses the key only for outgoing packets.
 Incoming packets with a different key or without a key will be treated as if they
 would belong to this interface.
 .Pp
-RFC1701 is not fully supported, however all unsupported features have been
-deprecated in RFC2784.
+The sequence number field also used only for outgoing packets.