[j-nsp] cheapest juniper router capable of lsys

[Vincent Bernat]

 ❦ 27 juin 2017 23:26 -0700, Chris Burton <chris.burton at speakeasy.net> :

> Interesting, in the kernel versions I tested I was not able to get it
> to work by just passing in the runtime changes to
> /sys/class/net/<bridge>/bridge/group_fwd_mask, I actually had to make
> changes to virtual bridge header file and recompile the kernel as
> there are/were safeguards in place to prevent someone from just making
> the runtime changes, which makes sense because this is a potentially
> dangerous change.  Recompiling is not a big deal, but would be
> interested to know which kernel versions you were able to get that to
> work with just runtime changes as that would save some time.

The different cases are handled here:
 http://elixir.free-electrons.com/linux/v4.11.5/source/net/bridge/br_input.c#L275

fwd_mask_required is not tunable by the user. Unless you are using
VLAN-aware bridges _and_ QinQ, its value is 0. group_fwd_mask is the
live value you put in sysfs, so it should work. There is a safeguard
mechanism to deny acceptance of 01-80-C2-00-00-[00,0B,0C,0D,0F] when
setting the group_fwd_mask value.

I didn't test recently, but I have used this mechanism in the past for
LLDP. Which kernel are you using?
-- 
10.0 times 0.1 is hardly ever 1.0.
            - The Elements of Programming Style (Kernighan & Plauger)