NSD - enable XDP in Debian?

NSD
1

Hi

I have uploaded nsd 4.13.0 to Debian unstable. According to your blog
post I noticed you added XDP support, but that it requires building with
--enable-xdp, see discussion:

https://blog.nlnetlabs.nl/enabling-more-default-features-in-nsd-4-13-0/
https://blog.nlnetlabs.nl/experimental-support-for-af_xdp-sockets-in-nsd/

What do you think about building with this flag in the Debian package?

Any reasons this may break unrelated things?

I think we are years away from a new Debian release, so it will only be
used by people tracking Debian unstable and testing, which I suspect few
use in production. Which may be a good fit to get wider testing.

/Simon

2

Hi,

What do you think about building with this flag in the Debian package?
[...] Which may be a good fit to get wider testing.

Building with XDP enabled in Debian testing would be great and indeed
a good fit to get wider testing.

Any reasons this may break unrelated things?

I don't think building with this flag would break anything unrelated.

(Our reason for the build flag was the introduction of additional
dependencies, which some people may find undesirable.)

Best,
Jannik

3

"Jannik Peters" <jannik@nlnetlabs.nl> writes:

Hi,

What do you think about building with this flag in the Debian package?
[...] Which may be a good fit to get wider testing.

Building with XDP enabled in Debian testing would be great and indeed
a good fit to get wider testing.

Thanks for confirming. I tried to enable it but ran into build errors:

https://salsa.debian.org/jas/nsd/-/jobs/8255756

As far as I some XDP objects are needed during linking, this patch fixed
it for us:

https://github.com/NLnetLabs/nsd/pull/460

With that it builds reasonable well:

https://salsa.debian.org/jas/nsd/-/pipelines/933804

Also, by default, it seems some *.o files are installed into
$(sharedfilesdir) which became /usr/share/nsd for me, see Makefile.in:

  if test -n "@xdp@"; then $(INSTALL_DATA) xdp-dns-redirect_kern.o $(DESTDIR)$(sharedfilesdir)/xdp-dns-redirect_kern.o; fi
  if test -n "@xdp@"; then $(INSTALL_DATA) xdp-dns-redirect_kern_pinned.o $(DESTDIR)$(sharedfilesdir)/xdp-dns-redirect_kern_pinned.o; fi

These are architecture-dependent files, aren't they? Is there some
standard non-/usr/share location for these files that you could use?
This may be a Debian-specific concern, I asked the same here:

https://lists.debian.org/debian-devel/2025/09/msg00143.html

/Simon

4

Hi Simon,

Also, by default, it seems some *.o files are installed into
$(sharedfilesdir) which became /usr/share/nsd for me, see Makefile.in:

  if test -n "@xdp@"; then $(INSTALL_DATA) xdp-dns-redirect_kern.o $(DESTDIR)$(sharedfilesdir)/xdp-dns-redirect_kern.o; fi
  if test -n "@xdp@"; then $(INSTALL_DATA) xdp-dns-redirect_kern_pinned.o $(DESTDIR)$(sharedfilesdir)/xdp-dns-redirect_kern_pinned.o; fi

These are architecture-dependent files, aren't they? Is there some
standard non-/usr/share location for these files that you could use?

Although these files are technically for a specific architecture (that being
eBPF), they are architecture-*in*dependent with regard to x86, ARM, etc.
eBPF programs are compatible across CPU architectures, as they get executed by
the eBPF "VM" inside the Linux kernel.

Best,
Jannik