common-utils: valid_host_name() should allow (sub)domains starting/ending with a digit

Some (sub)domains start or end with a digit. If this is the case, it
will not be possible to 'gluster peer probe' hosts in that (sub)domain.
This is overly restrictive, and RFC 1912 contains a note that describes
the common use of start/end digits in (sub)domains:
>
> Allowable characters in a label for a host name are only ASCII
> letters, digits, and the `-' character.  Labels may not be all
> numbers, but may have a leading digit  (e.g., 3com.com).  Labels must
> end and begin only with a letter or digit.  See [RFC 1035] and [RFC
> 1123].  (Labels were initially restricted in [RFC 1035] to start with
> a letter, and some older hosts still reportedly have problems with
> the relaxation in [RFC 1123].)  Note there are some Internet
> hostnames which violate this rule (411.org, 1776.com).
>

This change will also allow (sub)domains to consist out of digits only,
like the example of 411.org above. It is still not allowed to start or
and a (sub)domain with a `-' (dash) character.

Change-Id: Ia2b338b1f727c86ffcc3984d877b63c8476367e7
BUG: 863908
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/4017
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>
Reviewed-on: https://code.engineering.redhat.com/gerrit/60
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

0 files changed, 0 insertions, 0 deletions