Before this time accel-ppp always worked in "ip unnumbered" mode.
This option may turn this mode off (default is on)

After introduction offer-delay accel-ppp stopped to answer NAK for REQUESTs if requested session is not existing
to give chance other servers to reply. But this causes that some broken clients enter to infinite REQUEST loop.
This patch corrects this issue, so if offer-delay is not configured (means that this is only server in the net) or
after receiving few REQUESTs accel-ppp send NAK for non-existing sessions.

This reverts commit c317ff51.

First try to rename interface immediately and if it fails then do second try later just before bring interface up.
In case single-session=replace first try to rename interface may fail because first session may be active

Use separated thread to write messages to file instead of async io.
On mips platform async io does not work properly by some reason and may stuck logging

Check if there is space in previous chunk and append log data there.
This reduces memory usage and message fragmentation

Wait for previous session completely terminated before continuing authorization new session.

New options are applied to server option as server=...[,weight=x][,backup]
Weight is used for multi-server configurations (larger weight takes more users).
Backup is used to mark backup server f.e. server which will be used only if all other servers are failed.

By default list of IP address is serial at startup.
This option shuffles initial IP list so it becomes more random.

This new option will control how to represent Called-Station-ID.
Its value maybe ifname,mac or ifname:mac.
By default mac is used to keep compatibility with old versions.
Also old option ifname-in-sid is removed from documentation, but is still supported for compatibility.

There is no need to keep auth request structure in memory during whole session life time.
It wastes memory and file descriptors

* major l2tp rewrite
* introduced ipoe (ipv4 only) module

Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Use unshare(CLONE_FILES) to create a local file descriptors namespace
for the SNMP thread. This is similar to what was done in bf5340
'net-snmp: run snmp in "special" thread', but without calling clone()
directly. So the net-snmp plugin keeps running in a regular pthread.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>

This reverts commit bf534029.

snmp_thread() needs to be run as regular thread to allow Valgrind
analysis. Using a different namespace for file desciptors will be
done later on using unshare().
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>