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>

If accel-ppp is compiled with RADIUS support, but run without using it,
then pd->tmp_fname is NULL. This patch verifies that pd->tmp_fname is
valid before renaming the radattr file.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>

ipoe: early allocate interface for shared vlans (prevents different values of NAS-Port in Access-Request and Account-Request)
Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

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

NET-SNMP is built on top of stale file descriptor multiplexing mechanism (select)
which prevents to use descriptors with number >= 1024.
Due to accel-ppp uses a lots of descriptors NET-SNMP easy overflows this limit and fails
and even may crash whole accel-ppp process.
This patch runs snmp in special thread which does not share file descritor table
with main process, so it can use less descriptors and live in __FD_SETSIZE limit.
Signed-off-by: NDmitry Kozlov <xeb@mail.ru>

Wait for a full retransmission cycle after reception of a StopCCN.
Introduce STATE_FIN_WAIT to identify tunnels which have received a
StopCCN but are waiting for the disconnection timer to expire.

A tunnel can go from STATE_FIN (i.e. StopCCN has been sent, waiting for
acknowledgement) to STATE_FIN_WAIT (i.e. StopCCN has been received,
waiting for full retransmission cycle), but not the other way around.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>