From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michael Tremer <michael.tremer@ipfire.org>
To: development@lists.ipfire.org
Subject: Re: [PATCH] Add column with resolved hostname by IP address
Date: Fri, 24 Nov 2023 13:34:02 +0000
Message-ID: <B905C8E4-DB20-4EE2-B46A-8920AFF5A10B@ipfire.org>
In-Reply-To: <20231109213641.15840-1-sebastien.gislain@free.fr>
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Hello Sebastien,

Thank you very much for submitting this patch. However, I do have some concer=
ns about this being merged.

If you only have a couple of leases, everything is fine, but there are people=
 who have hundreds of DHCP clients on their network, and it has been reported=
 before that this page is loading extremely slow. Adding a DNS request to thi=
s will probably make loading the page many times slower than it already is.

And to consider the performance hit, I do not quite know what the benefit is =
of showing this. Should we not rather parse the DHCP leases file and show the=
 hostname that the client has submitted? That would show the same result, but=
 it would be a lot faster.

-Michael

> On 9 Nov 2023, at 21:36, Sebastien GISLAIN <sebastien.gislain(a)free.fr> wr=
ote:
>=20
> ---
> html/cgi-bin/dhcp.cgi | 7 +++++++
> 1 file changed, 7 insertions(+)
>=20
> diff --git a/html/cgi-bin/dhcp.cgi b/html/cgi-bin/dhcp.cgi
> index f45703f0b..aabf565d7 100755
> --- a/html/cgi-bin/dhcp.cgi
> +++ b/html/cgi-bin/dhcp.cgi
> @@ -21,6 +21,7 @@
>=20
> use strict;
> use experimental 'smartmatch';
> +use IO::Socket;
>=20
> # enable only the following on debugging purpose
> #use warnings;
> @@ -1009,6 +1010,7 @@ print <<END
> <tr>
>     <th width=3D'20%' align=3D'center'><a href=3D'$ENV{'SCRIPT_NAME'}?FETHE=
R'><b>$Lang::tr{'mac address'}</b></a></th>
>     <th width=3D'20%' align=3D'center'><a href=3D'$ENV{'SCRIPT_NAME'}?FIPAD=
DR'><b>$Lang::tr{'ip address'}</b></a></th>
> + <th width=3D'20%' align=3D'center'><b>$Lang::tr{'hostname'}</b></a></th>
>     <th width=3D'15%' align=3D'center'><b>$Lang::tr{'remark'}</b></th>
>     <th width=3D'15%' class=3D'boldbase' align=3D'center'><b>next-server</b=
></th>
>     <th width=3D'15%' class=3D'boldbase' align=3D'center'><b>filename</b></=
th>
> @@ -1106,9 +1108,14 @@ foreach my $line (@current2) {
> $TAG4 =3D "class=3D'red'" if ($dhcpsettings{'KEY2'} ne $key);
>     }
>=20
> + # resolved name (if exists)
> + my $iaddr =3D inet_aton($temp[1]);
> + my $rname =3D gethostbyaddr($iaddr, AF_INET);
> + if (!$rname || $rname eq "") { $rname =3D $Lang::tr{'lookup failed'}; }
>     print <<END
> <td align=3D'center' $col>$TAG2$temp[0]$TAG3</td>
> <td align=3D'center' $TAG4 $col>$TAG0$temp[1]$TAG1</td>
> +<td align=3D'center' $col>$rname&nbsp;</td>
> <td align=3D'center' $col>$temp[6]&nbsp;</td>
> <td align=3D'center' $col>$temp[3]&nbsp;</td>
> <td align=3D'center' $col>$temp[4]&nbsp;</td>
> --=20
> 2.39.2
>=20


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