Re: [libvirt] [PATCH] Add support for DNS TXT records
On 03/29/2011 12:52 PM, Michal Novotny wrote:
[snip]
> It would be great to:
>
> 1) add<user-class> and<vendor-class> tags inside<dhcp> that
allow
> filtering according to user/vendor classes
Well, I didn't know this is supported by DNSMasq but it seems to be
Yes, I am using it. :)
-4, --dhcp-mac=<network-id>,<MAC address>
Map from a MAC address to a network-id tag. The MAC
address may include wildcards. For example
--dhcp-mac=3com,01:34:23:*:*:* will set the tag "3com" for any host
whose MAC address matches the pattern.
Interesting.
> 2) allow to specify<bootp> inside those as well as
inside<range>
> or<host> elements.
Right, there's bootp option:
It's already supported by libvirt.
> 3) add support for DHCP options besides bootp, with a tag
like<option
> force="yes|no" name="..." value="...">.
>
> For example, my router's DHCP configuration would look like this:
>
> <dhcp>
> <range ...>
> <user-class prefix="iPXE">
> <bootp
file="http://playground.usersys.redhat.com/pxe/boot.ipxe">
> </user-class>
> <bootp file="undionly.kpxe">
> </dhcp>
>
That's not a bad idea at all and I think it's worth it however
originally my patch was about DNS and not DHCP.
Yes, of course.
Thinking more about it, <range ...> could also be (optionally) placed
inside <user-class> and <vendor-class> ("serve this range only to this
user class or vendor class").
I have to admit that DNS
TXT record only patch was not the right thing to be implemented since I
should have implemented all the DNS records supported
Should you? I am not sure of that. Are they really so useful, except
for CNAME (whose functionality dnsmasq more or less supports using A and
PTR records) and maybe SRV? Remember that A and PTR records are added
automatically by dnsmasq based on /etc/hosts.
Perhaps, you could implement (instead of tags for PTR, CNAME, etc.)
<dns>
<host ip="192.168.122.1">
<hostname>host1</hostname>
<hostname>host2</hostname>
<hostname>host3</hostname>
</host>
</dns>
instead, which would write a file
192.168.122.1 host1 host2 host3
and pass it to dnsmasq via --addn-hosts. But every feature should be
added as a separate patch.
I tried following invocations of dnsmasq (I tried it on port 52
instead
not to mess up with my current networking):
first-term# dnsmasq --strict-order --bind-interfaces
--pid-file=/var/run/libvirt/network/default.pid --conf-file=
--except-interface lo --listen-address 192.168.122.1 --dhcp-range
192.168.122.2,192.168.122.254
--dhcp-leasefile=/var/lib/libvirt/dnsmasq/default.leases
--dhcp-lease-max=253 --dhcp-no-override --no-daemon -p 52
--txt-record="some name","some value"
second-term$ dig TXT some name @192.168.122.1 -p 52
connection timed out; no servers could be reached
second-term$ dig TXT "some name" @192.168.122.1 -p 52
;; ANSWER SECTION:
some\032name. 0 IN TXT "some value"
This is just how dnsmasq prints the request. You can see with wireshark
that the request is really for "some name". BTW, please test your patch
with commas in the name. Those should be forbidden probably (not sure
about the value).
So what do you think about this? Also, do you think we should
implement
everything connected to DNSMasq mentioned there (i.e. both DNS and DHCP
stuff) in one commit, just few separate patches (e.g. one for DNS and
second for DHCP/BOOTP) ?
Many many separate patches.
BTW, regarding this particular series, you should update the XML schema,
and add many many testcases. Do this for TXT, then you can start
thinking about everything else.
Paolo