MFC r329105: ppp(8): fix code producing debugging logs

ppp(8): fix code producing debugging logs

Fix several cases when long buffer is copied to shorter one
using snprintf that results in contents truncation and
clobbering unsaved errno value and creation of misleading logs.

PR: 218517
Approved by: mav (mentor)

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

Fix multiple instances of the following clang 3.6.0 warning in ppp:

usr.sbin/ppp/command.c:2054:74: error: address of array 'arg->bundle->radius.cfg.file'
will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
if (arg->bundle->radius.alive.interval && !arg->bundle->radius.cfg.file) {
~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

In all cases, the file field of struct radius is a char array, but the
intent was to check whether the string is empty, so add an indirection
to achieve that. Use a similar approach for the sockname field of
struct server.

Ethernet vlan(4) interfaces have valid Ethernet link layer addresses but
use a different interface type (IFT_L2VLAN vs IFT_ETHER). Treat IFT_L2VLAN
interfaces like IFT_ETHER interfaces when handling link layer addresses.

Reviewed by: syrinx (bsnmpd)
MFC after: 1 week

Conditionally add the interface name and address if available
so that a ppp running in `receiver' (server) mode can properly
update routes, for example to update the MTU.

Submitted by: loos.br gmail.com (Luiz Otavio O Souza)
PR: bin/130159
PR: kern/125079, kern/122068, bin/126892
MFC after: 3 days

Add a radius_Flush() function that waits for the response (or timeout) to
any pending RADIUS transaction. Use this before sending RAD_STOP RADIUS
messages so that we definitely ``stop'' the session.

It was discovered that sometimes when the link timed out, we got lucky
enough to have an un-ACK'd RADIUS accounting transaction in progress,
resulting in the RAD_STOP message failing to send.

Original report found on: A russion news group
Text translated by: glebius
Tested by: Alexey Popov llp at iteranet dot com
MFC after: 7 days

Make ppp WARNS=5 clean

Do RADIUS accounting on IPV6CP.

MFC after: 1 week

Install routes specified by Framed-IPv6-Route. Since the format
of Framed-IPv6-Route is user defined, it follows Framed-IP-route.

MFC after: 1 week

MYADDR6 in ppp.link{up,down} should match even when IPCP is enabled.

MFC after: 1 week

Add missing header for system_Select() prototype

Set link-local address of tun interface with prefixlen = 64
instead of 128. It makes RA happy.

Reported by: rafa@dif.um.es,
SHIRASAKI Yasuhiro <yasuhiro@nttv6.jp>
Reviewed by: SHIRASAKI Yasuhiro <yasuhiro@nttv6.jp>
MFC after: 1 week

Once ppp session is over, the route to ff02::tun0/32 was
deleted, and never came back. Now, the route to
ff02::tun0/32 is installed at the end of IPV6CP negitiaton.

Since ppp.link{up,down} is invoked at the end of IPCP negotiation, if
we need ppp.link{up,down}, we couldn't disable IPCP. Now, if IPCP is
disabled, ppp.link{up,down} is invoked at the end of IPV6CP
negotiation.

- made ppp compliant to RFC 2472 (based on a patch from another
contributor)
- support ipv6cpretry and ipv6cpretries, which are IPv6 versions
of ipcpretry and ipcpretries.
- improve handling of IPv6 link-local addresses

Submitted by: JINMEI Tatuya <jinmei@isl.rdc.toshiba.co.jp>

Include the correct file (stdarg.h) and use va_list rather than _BSD_VA_LIST_

Suggested by: mike

Make the way FSM options are processed easier to read by using structures
instead of u_char *.

The changes are cosmetic except:

RecvConfigAck() now displays the options that are being ACK'd
Huge (bogus) options sent from the peer won't cause an infinite loop
SendIdent and ReceiveIdent are displayed consistenlty with other FSM data
LCP AUTHPROTO options that aren't understood are NAK'd, not REJ'd

Add a missing % in a format string.

Not spotted by: FreeBSD's gcc version 2.95.3 20010315 (release)
Spotted by: OpenBSD's gcc version 2.95.3 20010125 (prerelease)

Back out the previous fix to deal with kernels that don't support IPv6,
and implement a far more subtle and correct fix.

The reason behind the infinite loop was that ppp was trying to make up
initial IPv6 numbers and wasn't giving up when it failed unexpectedly to
assign the addresses it just fabricated to it's interface (thinking that
the reason was because another interface was using the same address).
It now attempts this up to 100 times before just failing and trying to
muddle along (in reality, this should never happen more than a couple
of times unless our random number generator doesn't work).

Also, when IPv6 is not available, don't even try to assign the IPv6
interface address in the first place...

Run correctly on a machine built without AF_INET6 support

Specify the gateway address when updating the MTU and send/recv pipe
sizes on a route.

IMHO this shouldn't be necessary (the destination & mask/prefixlen
should be enough), but without it, the default route update under
OpenBSD will fail.

Thanks to: Russell T Hunt <alaric@MIT.EDU>

o Add ipv6 support, abstracting most NCP addresses into opaque
structures (well, they're treated as opaque).

It's now possible to manage IPv6 interface addresses and routing
table entries and to filter IPV6 traffic whether encapsulated or
not.

IPV6CP support is crude for now, and hasn't been tested against
any other implementations.

RADIUS and IPv6 are independent of eachother for now.

ppp.linkup/ppp.linkdown aren't currently used by IPV6CP

o Understand all protocols(5) in filter rules rather than only a select
few.

o Allow a mask specification for the ``delete'' command. It's now
possible to specifically delete one of two conflicting routes.

o When creating and deleting proxy arp entries, do it for all IPv4
interface addresses rather than doing it just for the ``current''
peer address.

o When iface-alias isn't in effect, don't blow away manually (via ``iface
add'') added interface addresses.

o When listening on a tcp server (diagnostic) socket, bind so that a
tcp46 socket is created -- allowing both IPv4 and IPv6 connections.

o When displaying ICMP traffic, don't display the icmp type twice.
When display traffic, display at least some information about unrecognised
traffic.

o Bump version

Inspired after filtering work by: Makoto MATSUSHITA <matusita@jp.FreeBSD.org>