This attribute's handling is broken. It can only be used when creating
Ethernet pseudo-wires, in which case its value can be used as the
initial MTU for the l2tpeth device.
However, when handling update requests, L2TP_ATTR_MTU only modifies
session->mtu. This value is never propagated to the l2tpeth device.
Dump requests also return the value of session->mtu, which is not
synchronised anymore with the device MTU.

The same problem occurs if the device MTU is properly updated using the
generic IFLA_MTU attribute. In this case, session->mtu is not updated,
and L2TP_ATTR_MTU will report an invalid value again when dumping the
session.

It does not seem worthwhile to complexify l2tp_eth.c to synchronise
session->mtu with the device MTU. Even the ip-l2tp manpage advises to
use 'ip link' to initialise the MTU of l2tpeth devices (iproute2 does
not handle L2TP_ATTR_MTU at all anyway). So let's just ignore it
entirely.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This field is not used.

Treat PPPIOC*MRU the same way as PPPIOC*FLAGS: "get" requests return 0,
while "set" requests vadidate the user supplied pointer but discard its
value.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The value of this attribute is never used.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The value of this attribute is never used.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reviewed-by: NGuillaume Nault <g.nault@alphalink.fr>
Tested-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The "offset" option has been removed by
commit 900631ee ("l2tp: remove configurable payload offset").
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Acked-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Revert commit f15bc54e ("l2tp: add peer_offset parameter"). This
is removed because it is adding another configurable offset and
configurable offsets are being removed.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce peer_offset parameter in order to add the capability
to specify two different values for payload offset on tx/rx side.
If just offset is provided by userspace use it for rx side as well
in order to maintain compatibility with older l2tp versions
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2.  Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier.  The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception.  SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.  See the previous patch in this series for the
methodology of how this patch was researched.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Because of <linux/libc-compat.h> interface limitations, <netinet/in.h>
provided by libc cannot be included after <linux/in.h>, therefore any
header that includes <netinet/in.h> cannot be included after <linux/in.h>.

Change uapi/linux/l2tp.h, the last uapi header that includes
<netinet/in.h>, to include <linux/in.h> and <linux/in6.h> instead of
<netinet/in.h> and use __SOCK_SIZE__ instead of sizeof(struct sockaddr)
the same way as uapi/linux/in.h does, to fix linux/if_pppol2tp.h userspace
compilation errors like this:

In file included from /usr/include/linux/l2tp.h:12:0,
                 from /usr/include/linux/if_pppol2tp.h:21,
/usr/include/netinet/in.h:31:8: error: redefinition of 'struct in_addr'

Fixes: 47c3e778 ("net: l2tp: deprecate PPPOL2TP_MSG_* in favour of L2TP_MSG_*")
Signed-off-by: NDmitry V. Levin <ldv@altlinux.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the L2TP_MSG_* definitions to UAPI, as it is part of
the netlink API.
Signed-off-by: NAsbjoern Sloth Toennesen <asbjorn@asbjorn.st>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The attributes L2TP_ATTR_UDP_ZERO_CSUM6_RX and
L2TP_ATTR_UDP_ZERO_CSUM6_TX are used as flags,
but is defined as a u8 in a comment.

This patch redocuments them as flags.

Adding nla_policy entries would break API, so not doing that.

CC: Tom Herbert <therbert@google.com>
Signed-off-by: NAsbjoern Sloth Toennesen <asbjorn@asbjorn.st>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nla_data() is now aligned on a 64-bit area.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Previously l2tp module did not provide any means for the user space to
get notified when tunnels/sessions are added/modified/deleted.
This change contains the following
- create a multicast group for the listeners to register.
- notify the registered listeners when the tunnels/sessions are
  created/modified/deleted.
Signed-off-by: NBill Hong <bhong@brocade.com>
Reviewed-by: NStephen Hemminger <stephen@networkplumber.org>
Reviewed-by: NSven-Thorsten Dietrich <sven@brocade.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Added new L2TP configuration options to allow TX and RX of
zero checksums in IPv6. Default is not to use them.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

L2TPv3 defines an IP encapsulation packet format where data is carried
directly over IP (no UDP). The kernel already has support for L2TP IP
encapsulation over IPv4 (l2tp_ip). This patch introduces support for
L2TP IP encapsulation over IPv6.

The implementation is derived from ipv6/raw and ipv4/l2tp_ip.
Signed-off-by: NChris Elston <celston@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for unmanaged L2TPv3 tunnels over IPv6 using
the netlink API. We already support unmanaged L2TPv3 tunnels over
IPv4. A patch to iproute2 to make use of this feature will be
submitted separately.
Signed-off-by: NChris Elston <celston@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Complete the work started with commit
6602a4ba ('net: Make userland include
of netlink.h more sane').
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In L2TPv3, we need to create/delete/modify/query L2TP tunnel and
session contexts. The number of parameters is significant. So let's
use netlink. Userspace uses this API to control L2TP tunnel/session
contexts in the kernel.

The previous pppol2tp driver was managed using [gs]etsockopt(). This
API is retained for backwards compatibility. Unlike L2TPv2 which
carries only PPP frames, L2TPv3 can carry raw ethernet frames or other
frame types and these do not always have an associated socket
family. Therefore, we need a way to use L2TP sessions that doesn't
require a socket type for each supported frame type. Hence netlink is
used.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Reviewed-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a new L2TPIP socket family and modifies the core to
handle the case where there is no UDP header in the L2TP
packet. L2TP/IP uses IP protocol 115. Since L2TP/UDP and L2TP/IP
packets differ in layout, the datapath packet handling code needs
changes too. Userspace uses an L2TPIP socket instead of a UDP socket
when IP encapsulation is required.

We can't use raw sockets for this because the semantics of raw sockets
don't lend themselves to the socket-per-tunnel model - we need to
Signed-off-by: NDavid S. Miller <davem@davemloft.net>