[OpenWrt-Devel] [PATCH] modules: package l2tp_ip6.ko in kmod-l2tp-ip6

Daniel Golle daniel at makrotopia.org
Sun May 3 05:37:52 EDT 2015

Hi Steven,

On Sun, May 03, 2015 at 10:28:16AM +0200, Steven Barth wrote:
> On 02.05.2015 13:33, Daniel Golle wrote:
> >r45593 includes l2tp_ip6 in the kmod-l2tp-ip package.
> >This is not feasible for several reasons:
> >  - in a given setup one usually uses either l2tp_ip or
> >    l2tp_ip6, but never both
> I disagree here, if you e.g. use a hostname and resolve that before
> connecting this would dynamically resolve to either IPv6 or IPv4.

Given that there are the right support-tools around iproute2 to
resolve the hostname and pick the right local address, this is
indeed a valid scenario I didn't consider (due to the lack of
tools actually doing the magic).
For now I've been using L2TP with pre-configured addresses and
predictable use of either address family.

(see: https://gist.github.com/dangowrt/a1b816b509a8def28c0e )

Anyway, I get that argument, but it could still be solved by
adding +IPV6:kmod-l2tp-ip6 as a dependency to kmod-l2tp-ip.

If it's really about the packaging overhead, it would also
be possible to only include l2tp_ip6.ko in FILES if IPV6 is set,
thus getting rid of the kmod-ipv6 dependency on non-IPv6 systems.

In the long-run, I dream about native L2TPv3 integration in
netifd using netlink, just like GRE tunnels are supported in


That could then take care of resolving hostnames, adding host-
routes and all that...

What are you using to setup pseudo-wires in OpenWrt after



> >  - l2tp_ip doesn't depend on ipv6
> True, I'm not sure if it makes sense to have IPv6 as an external module any
> longer since its been a while and its enabled by default anyway. I guess
> after the CC branch we might want to enable it in the default kernel config
> and remove the module packaging. This would also save some space in the end.

There are still many cases where people use ImageBuilder to have a
firmware without IPv6, so they can use the space for other things.
I don't like that approach either and only know about it because
these systems then don't respond to IPv6 link-local multicast ping
which is one of my most used tools in my personal maintainance

So I generally agree, but it's something to happen in the future
which hasn't happened yet...
And won't we one day package IPv4 as an optional module instead then?

> >  - versioning of kmod-l2tp-ip doesn't indicate that it
> >    now does include support for L2TP-over-IPv6
> Versioning is based on the kernel, so I don't think I get this argument.

Right, the fact that versioning is based on the kernel is exactly the
problem here. Imagine that I'm using a 3.14-based locally maintained
OpenWrt branch and provide updates via a feed. Now some user asked me
for l2tp_ip6 support and I'd like to tell her, "yes, it's available now.
Go ahead an install kmod-...".
Now the user already got kmod-l2tp-ip installed, so opkg won't re-install
the package as it believes it's up-to-date. I guess that should explain


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