On Sun, 2005-01-16 at 13:55, Lennert Buytenhek wrote:
> Another argument against etherip would be that OpenBSD apparently
> mis-implemented etherip by putting the etherip version nibble in the
> second nibble of the etherip header instead of the first, which would
> probably prevent the linux and OpenBSD versions from interoperating,
> negating the advantage of using etherip in the first place.
Should be pretty easy for them to fix, no?
> All I personally care about is that when I install a random linux distro
> two years from now, that ethernet-over-IP tunneling will simply work, using
> whatever protocol -- I don't care about which.
> Any opinions?
My opinion is it doesnt harm to have it in. BTW, in one of your emails i
noticed you cced the authors of that RFC - did they respond? Whats their
> If we do end up using GRE for ethernet tunneling, there's some work that
> needs to be done. For one, ip_gre in its current form would need a certain
> amount of hacking for tunneling ethernet frames instead of IPv4/IPv6 as
> it does now. We might as rename it to plain 'gre' and move it out of
> net/ipv4/ to net/core/ or something while we're at it.
> The way we currently use (f.e. in iproute2) for finding out whether a
> given netdevice is a tunnel or not is by looking at ARPHRD_*, but this
> scheme breaks down for ethernet tunnels,
the dev->type is intended precisely for that. So if this needs a new
type then you should introduce a new ARPHRD type for it and set it at
device creation time.
> since there is no other way of
> distinguishing them from regular ethernet devices. We could issue
> SIOCGETTUNNEL and see if that succeeds, but that unfortunately aliases
> with SIOCDEVPRIVATE which aliases to BOND_ENSLAVE_OLD, SIOCGMSTATS,
> EQL_ENSLAVE, FRAD_GET_CONF, SIOCDEVPLIP, SIOCGPPPSTATS and a million
> others, so you never know if the netdevice really interpreted it as
> SIOCGETTUNNEL or no.
Introducing the new type should help. Also the iflink is typically set
to the mother netdevice. So that should go a long way to give you
Ia m not sure about this ioctl stuff - but shouldnt there be a backway
via netlink for all these details.
> Other things that suck about tunneling?
> - If we're going to overhaul the way tunneling works, we should try to
> remove the need for the gre0 interface as well.
Why is this first instance needed? Its not like theres a bus that is
scanned at boot time and we need to create at that discovery time.
> - Tunneling over IPv6 should be implemented.
sit? or v6-v6?
> - How to share more code between sit/ipip/gre?
Lots of shareable stuff there.
BTW, have you looked at any of the L2VPN stuff? browse the ietf web
page. Some interesting stuff there.