License cleanup: add SPDX license identifier to uapi header files with no license

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: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ip6_tunnel: Allow rcv/xmit even if remote address is a local address

Currently, ip6_tnl_xmit_ctl drops tunneled packets if the remote
address (outer v6 destination) is one of host's locally configured
addresses.
Same applies to ip6_tnl_rcv_ctl: it drops packets if the remote address
(outer v6 source) is a local address.

This prevents using ipxip6 (and ip6_gre) tunnels whose local/remote
endpoints are on same host; OTOH v4 tunnels (ipip or gre) allow such
configurations.

An example where this proves useful is a system where entities are
identified by their unique v6 addresses, and use tunnels to encapsulate
traffic between them. The limitation prevents placing several entities
on same host.

Introduce IP6_TNL_F_ALLOW_LOCAL_REMOTE which allows to bypass this
restriction.

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

uapi: fix linux/ip6_tunnel.h userspace compilation errors

Include <linux/if.h> and <linux/in6.h> to fix the following
linux/ip6_tunnel.h userspace compilation errors:

/usr/include/linux/ip6_tunnel.h:23:12: error: 'IFNAMSIZ' undeclared here (not in a function)
char name[IFNAMSIZ]; /* name of tunnel device */
/usr/include/linux/ip6_tunnel.h:30:18: error: field 'laddr' has incomplete type
struct in6_addr laddr; /* local tunnel end-point address */

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>