MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

When ``ppp -direct'' is invoked by a program that uses pipe(2) to
create stdin and stdout, don't blindly try to use stdin as a bi-directional
channel. Instead, detect the pipe and set up a special exec handler
that indirects write() calls through stdout.

This fixes the problem where ``set device "!ssh -e none host ppp
-direct label"'' no longer works with an openssh-5.2 server side as
that version of openssh ignores the USE_PIPES config setting and
*always* uses pipes (rather than socketpair) for stdin/stdout channels.

MFC after: 3 days

Make ppp WARNS=5 clean

o Clean up some #includes
o Bump version number to 3.0.4
o When talking to a RADIUS server, provide a NAS-Port-Type.

When the NAS-Port-Type is Ethernet, provide a NAS-Port value equal
to the SESSIONID from the environment in direct mode or the
NGM_PPPOE_SESSIONID message in other modes. If no SESSIONID is found,
default to the interface index in client mode or zero in server mode.

When the NAS-Port-Type is ISDN, set the NAS-Port to the minor number
of the physical device (ie, the N in /dev/i4brbchN).

This makes it easier for the RADIUS server to identify the client
WRT accounting data etc.

Prompted by: lsz8425 <lsz8425@mail.cd.hn.cn>

Merge the NETGRAPH branch into HEAD. tty devices now use netgraph's line
discipline to do the async escaping, but no other benefits are available yet.

Change ``ifdef HAVE_DES'' to ``ifndef NODES'' for consistency.

Make the Makefile a little more sane WRT RELEASE_CRUNCH.

Handle hardware-imposed MTU/MRU limitations. PPPoE will no longer
allow MRU/MTU negotiations to exceed 1492.

Add an optional ``max'' specifier to ``set m[rt]u'', ie.

set mtu max 1480

Bump the ppp version number.

Sponsored by: Monzoon Networks AG and FreeBSD Services Limited

Make -DNOSUID (or -DPPP_NOSUID) possible to build ppp without SUID
capabilities.

Correct PPPoE in multi-link mode
Submitted by: jason@OpenBSD.org

Remove an unused variable

Honour ``set speed sync'' and ``set device !program'' when
used together by creating a SOCK_DGRAM socketpair() between
the processes.

Be polite when closing !program links and send a HUP to the
process. This makes ssh tunnels over unreliable media (such
as via httptunnel) reconnect properly.

Do some vfork() trickery so that the parent can determine
if the childs exec() has succeeded or failed by taking advantage
of the fact that both processes share the same memory.

FWIW:
I tried to implement this by doing a pipe(), setting the
write desciptors close-on-exec flag in the child and writing
errno to the descriptor if the exec() fails. The parent can
then ``if (read()) got errno else exec worked''.

This didn't work though - the child could write() to fd[1] on
exec failure, but the parent got 0 trying to read() from fd[0] !
Is this a bug in execve() ?

Correct some typos introduced in the descriptor -> fdescriptor change.

To avoid namespace polution in NetBSD:

``struct descriptor'' -> ``struct fdescriptor''

Add a few missing #includes

Correct usages of getuid() and geteuid()

Pointed out by: billf

Don't allowt '#' as a comment when it's embedded in quotes:

set something "xxx yyy # zzz" aaa

shouldn't be interpreted as

set something "xxx yyy" aaa

Don't munge ``set dial|login|logout|hangup'' arguments before
ExpandString() has a chance to do its own substitutions.

Notice and warn about unterminated quoted strings in commands.
The entire command is ignored if the syntax is invalid...

Change ``set cd'' so that its default value is device specific. The
default is still 1 second for ttys, but is now 6 seconds for i4b (ISDN)
devices and 5 seconds for ethernet (PPPoE) devices.

Support PPPoE

Help (lots) from: julian, archie
Facilities from: ahebert@pubnix.net

Back out the bogus #ifdef __NetBSD__ #include <signal.h> lines.
The original report was due to a mis-installation of the NetBS
header files :-/

Submitted by: Kazuyoshi Kato <kazk@yyy.or.jp>

NetBSD has moved ``extern int errno;'' to signal.h :-/

Submitted by: Kazuyoshi Kato <kazk@yyy.or.jp>

$Id$ -> $FreeBSD$

Set the close-on-exec flag for all unused descriptors when
exec()ing other programs.

Add ISDN support via isdnd & i4b. This requires version
0.81.1 of the i4b code - namely support of the I4B_VR_REQ
ioctl via the i4brbchX device.

Ppp controls the phone number, but idle timers and
SYNC/RAW decisions are still made by isdnd (in isdnd.rc).

This involves a new datalink state machine phase. The
``wait for carrier'' phase happens after dialing but
before logging in. The whole dial state should really
be abstracted so that each device type can deal with it
in its own way (thinking about PPPoE) - but that'll have
to wait.

The ``set cd'' symantics remain the same for tty devices,
but we now delay until we either get CD or timeout waiting
(at which time we drop the link if we require CD).

For i4b devices we always insist on carrier.

Thanks to hm@ for his help, and especially for pointing out
that I *don't* need to re-implement isdnd (that was a huge
waste of time !) :-]

Use the correct pid when substituting PROCESSID.
Problem reported by: Amedeo Beck Peccoz <gea@gressoney.it>

Correct the way ppp transfers links on the server side in MP
mode by padding out the ``struct device'' to the maximum
device size.
Bump the ppp version number to indicate the transfer format
change.

This should make MP over tty and udp devices functional again.

Increase the length of an individual device name to LINE_LEN.
Adjust the base physical device name correctly after a link
transfer (allowing correct multilink callbacks).

Correct the ``ignoring sync/async'' warnings so that they show
up with the correct device type.
Reassign the correct tcpdevice or execdevice after transfering
a link in MP server mode.

Allow ``host:port/udp'' devices and support ``host:port/tcp'' as
being the same as the previous (still supported) ``host:port''
syntax for tcp socket devices.

A udp device uses synchronous ppp rather than async, and avoids
the double-retransmit overhead that comes with ppp over tcp (it's
usually a bad idea to transport IP over a reliable transport that
itself is using an unreliable transport). PPP over UDP provides
througput of ** 1.5Mb per second ** with all compression disabled,
maxing out a PPro/200 when running ppp twice, back-to-back.

This proves that PPPoE is plausable in userland....

This change adds a few more handler functions to struct device and
allows derivations of struct device (which may contain their own
data etc) to pass themselves through the unix domain socket for MP.
** At last **, struct physical has lost all the tty crud !

iov2physical() is now smart enough to restore the correct stack of
layers so that MP servers will work again.

The version number has bumped as our MP link transfer contents have
changed (they now may contain a `struct device').

Don't extract the protocol twice in MP mode (resulting in protocol
rejects for every MP packet). This was broken with my original
layering changes.

Add ``Physical'' and ``Sync'' log levels for logging the relevent
raw packets and add protocol-tracking LogDEBUG stuff in various
LayerPush & LayerPull functions.

Assign our physical device name for incoming tcp connections by
calling getpeername().

Assign our physical device name for incoming udp connections from
the address retrieved by the first recvfrom().

o Redesign the layering mechanism and make the aliasing code part of
the layering.

We now ``stack'' layers as soon as we open the device (when we figure
out what we're dealing with). A static set of `dispatch' routines are
also declared for dealing with incoming packets after they've been
`pulled' up through the stacked layers.

Physical devices are now assigned handlers based on the device type
when they're opened. For the moment there are three device types;
ttys, execs and tcps.

o Increment version number to 2.2
o Make an entry in [uw]tmp for non-tty -direct invocations (after
pap/chap authentication).
o Make throughput counters quad_t's
o Account for the absolute number of mbuf malloc()s and free()s in
``show mem''.
o ``show modem'' becomes ``show physical''.