[bind10-dev] Last name used after $INCLUDE

[Mark Andrews]

In message <20121217170639.GA13833 at hydra>, Michal 'vorner' Vaner writes:
> 
> Hello
> 
> There's an interesting case with master files. As jinmei pointed out in
> https://bind10.isc.org/ticket/2427#comment:11, it is not clear what should =
> be
> considered the previous name after a $INCLUDE directive:
> 
> | foo.example.com. IN A 192.0.2.1
> | $INCLUDE some_file ; which ends with "bar.example.com. IN A 192.0.2.2"
> |      IN AAAA 2001:db8::1
> |
> | Which name should be used for the AAAA RR? RFC1035 doesn't seem to
> | be clear on this point; BIND 9 uses foo.example.com; NSD uses
> | bar.example.com. In my understanding, your current implementation
> | behaves like NSD.
> 
> I adopted the bind9 approach (after seeing this comment, I must admit I did=
> n't
> think of that corner case at first) and added a warning whenever this is fo=
> und.
> But is there a rationale behind bind9's or NSD's behaviour?

          <sect3>
            <title>The <command>$INCLUDE</command> Directive</title>
            <para>
              Syntax: <command>$INCLUDE</command>
              <replaceable>filename</replaceable>
              <optional>
<replaceable>origin</replaceable> </optional>
              <optional> <replaceable>comment</replaceable> </optional>
            </para>
            <para>
              Read and process the file <filename>filename</filename> as
              if it were included into the file at this point.  If <command>origin</command> is
              specified the file is processed with <command>$ORIGIN</command> set
              to that value, otherwise the current <command>$ORIGIN</command> is
              used.
            </para>
            <para>
              The origin and the current domain name
              revert to the values they had prior to the <command>$INCLUDE</command> once
              the file has been read.
            </para>
            <note>
              <para>
                RFC 1035 specifies that the current origin should be restored
                after
                an <command>$INCLUDE</command>, but it is silent
                on whether the current
                domain name should also be restored.  BIND 9 restores both of
                them.
                This could be construed as a deviation from RFC 1035, a
                feature, or both.
              </para>
            </note>
          </sect3>

> 
> Thanks
> 
> --=20
> I've already told you more than I know.
> 
> Michal 'vorner' Vaner
> 
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org