A poorly written, minimum viable PPPoE client with session handoff between redundant FreeBSD routers
ppp_thing allows you to move a PPPoE session between two FreeBSD routers, based on which router is master for a configured CARP address. This can be combined with pfsync to communicate NAT tables and provide a seamless failover in case of hardware failure or planned maintenance.
Session data is kept in /var/db/ppp_thing.state to be used if the
daemon restarts. Maybe useful for reboots on a single host, if your system
restarts faster than the Access Concentrator times out the session.
make
make install
add a config in /usr/local/etc/ppp_thing.conf; this is a simple line
oriented config file that looks like:
Interface where PPPoE runs
xx:xx:xx:xx:xx:xx <- mac address to use
username
password
MTU <- probably 1492
a.b.c.d <- CARP address to watch
e.f.g.h <- local address
i.j.k.l <- peer address
The mac address should be different from the physical address of the two peer routers; because whichever peer is master for the CARP address will use it for the PPPoE session. See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local_(U/L_bit) for guidance on picking a locally administered mac address.
The local address is assigned to the ppp interface (ng0), rather than the negotiated address; that way connections initiated from the active router can be routed through the peer when the CARP address fails over, and the peer becomes the active router. The negotiated address is assigned to a dummy interface (ng1), which can be used for configuring PF nat.
Once configured service ppp_thing onestart should start it up. You
will need to load the ng_ether module, or include it in your kernel.
Richard Russo - pppoe@enslaves.us
Distributed under the BSD license. See LICENSE for more information.
https://github.com/russor/ppp_thing
Please send me an email to discuss before starting work. I've kept things pretty simple, because this is good enough for me, and it's 2021. Ideally, PPPoE should be dead or dying, not seeing new development.
However, if you want to make some protocol correctness mentioned in the header of the code changes, or your ISP is enlightned enough to support PPP-Max-Payload, and you've got a patch to make that work; that sounds good.
Or if you found a crash, or using unitialized memory etc, please report (or patch).
If you really want a good PPPoE client, https://sourceforge.net/projects/mpd/ looks like a good choice; but it doesn't have a way (that I could see) to share a session between two peers.