Support for CIDR address format

[dimagafurov]

In Debian 9 Stretch it is possible to set up addresses in CIDR format.

Example

iface eth0 inet static
        address 192.168.99.1/24
        gateway 192.168.99.1
        name eth0

instead of:

iface eth0 inet static
        address 192.168.99.1
        netmask 255.255.255.0
        gateway 192.168.99.1
        name eth0

Debinterfaces currently does not support this and it gives ValueError on validating IP addres when trying to parse interfaces file

[nMustaki]

Hi, Does using the CIDR add some useful information ? Should we do something with it instead of just ignoring it ?

…

-- /* ** "What do you despise? By this you are truly known." ** from Manual of Muad'Dib by the Princess Irulan. */

On Fri, Feb 23, 2018 at 1:55 PM, dimagafurov ***@***.***> wrote: In Debian 9 Stretch it is possible to set up addresses in CIDR format. Example iface eth0 inet static address 192.168.99.1/24 gateway 192.168.99.1 name eth0 instead of: iface eth0 inet static address 192.168.99.1 netmask 255.255.255.0 gateway 192.168.99.1 name eth0 Debinterfaces currently does not support this and it gives ValueError on validating IP addres when trying to parse interfaces file — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#26>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA-fUYuTAhlUzOrjGMji4aRoa__F2wONks5tXrVEgaJpZM4SQ16c> .

[dimagafurov]

Hi,
It doesn't add any useful information, it is absolutely equivalent to format with separate address and netmask.
But it breaks down the cases when we need to parse interface file generated by some other software. For example, Debian Stretch Installer writes interfaces file in CIDR format.

[nMustaki]

That's what I thought too, just wanted to be sure. ​ So the big issue is whether to ​: - accept IPs in CIDR format and handle them everywhere in the code - convert CIDR into 'classic' address + netmask At first glance, it seems to me the second solution may better help Debinterface's users by shielding them from the CIDR format if they don't expect it. What do you think ? Besides, do you know what happens if there are both CIDR and netmask ? Should we raise a ValueError on this one ? Thanks, Nathan

…

-- /* ** "What do you despise? By this you are truly known." ** from Manual of Muad'Dib by the Princess Irulan. */

On Fri, Feb 23, 2018 at 3:09 PM, dimagafurov ***@***.***> wrote: Hi, It doesn't add any useful information, it is absolutely equivalent to format with separate address and netmask. But it breaks down the cases when we need to parse interface file generated by some other software. For example, Debian Stretch Installer writes interfaces file in CIDR format. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#26 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA-fUT-J_dFTNYPi08dhwUVhzdJI9ZGqks5tXsaxgaJpZM4SQ16c> .

[dimagafurov]

I think the second solution is just enough - convert CIDR into 'classic' address + netmask, as I don't see any difference in system behavior depending of address format.

Besides, do you know what happens if there are both CIDR and netmask ?

I will test it in an hour or two and write here

[dimagafurov]

According to the manpage we can use address as dotted quad/netmask and netmask can be dotted quad or CIDR
so valid formats are:

iface eth0 inet static
        address 192.168.99.1/24

iface eth0 inet static
        address 192.168.99.1/255.255.255.0

iface eth0 inet static
        address 192.168.99.1/24
        netmask 255.255.255.0

iface eth0 inet static
        address 192.168.99.1
        netmask 24

If both "classic" and CIDR format present it uses netmask option, but I get it experimentally, I cannot found it documented

[dimagafurov]

I made quick and ugly workaround for my purposes, it is completely not production-ready but maybe it will be useful

[nMustaki]

Many thanks for the researches ! I don't have much free time in the next 2-3 weeks, but if you have I'll deploy the new release right away.

…

-- /* ** "What do you despise? By this you are truly known." ** from Manual of Muad'Dib by the Princess Irulan. */

On Fri, Feb 23, 2018 at 5:49 PM, dimagafurov ***@***.***> wrote: I made quick and ugly workaround for my purposes, it is completely not production-ready but maybe it will be useful — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#26 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA-fUUzM425QK5X9q3xYG6EItTNXeD_Pks5tXuwhgaJpZM4SQ16c> .

[gdressel]

The package netaddr has a nice implemenation for CIDR processing.
You might consider using this in debinterface.

[nMustaki]

Hi @guedressel , I don't want to add a dependency if I can help it, as this library is used in some places where disk space and internet access is limited. It aso add synchronisation costs with the netaddr library, even if it's quite stable at this point. I'm open to discussion though !