tinyDNS deconstruct.

0xdeadbad has asked for the wisdom of the Perl Monks concerning the following question:

Could somebody lend a hand with deconstructing tinydns CAA records please.

"\000\005issueentrust.net"   > "CAA   IN  0       issue entrust.net"
                                          [flag]  [tag] [issuer]
[download]

The first octal is the Flag ( 000 )
The second octal ( 005 ) is the taglength and used to deduce the tag and issuer from the ascii string.

If I could just get "\000\005issueentrust.net" translated to "0,5,issueentrust.net" that would be a great help. I've been looking at pack and unpack but cannot work it out as I'm not a real programmer.

many thanks

Comment on tinyDNS deconstruct. Download Code

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Re: tinyDNS deconstruct. by AnomalousMonk (Archbishop) on Feb 15, 2018 at 17:50 UTC
... just get "\000\005issueentrust.net" translated to "0,5,issueentrust.net" ... Try: `c:\@Work\Perl\monks>perl -wMstrict -le "my $s = qq{\000\005issueentrust.net}; $s =~ s{ \A (.) (.) }{ sprintf '%d,%d,', ord($1), ord($2) }xmse; print qq{'$s'}; " '0,5,issueentrust.net'` [download] Update 1: But this sounds like an XY Problem; it that really all you want? Update 2: Here's an unpack approach: `c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "my $s = qq{\000\005issueentrust.net}; my ($flag, $tag, $issuer) = unpack 'C C/a a', $s; dd $flag, $tag, $issuer; my $t = sprintf '%-6s %s %s', $flag, $tag, $issuer; print qq{'$t'}; " (0, "issue", "entrust.net") '0 issue entrust.net'` [download] (Update:* Changed `$remainder` to `$issuer` in this code example because this naming corresponds better to terminology used in the OP.) Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^2: tinyDNS deconstruct. by 0xdeadbad (Novice) on Feb 16, 2018 at 09:29 UTC
Great,many thanks. Your unpack template was just what I needed.	[reply]
Re: tinyDNS deconstruct. by atcroft (Abbot) on Feb 15, 2018 at 19:45 UTC
I know you may have your reasons for looking at the record in a particular way, but why not use a module that is made for doing this, Net::DNS? Below was a quick example of using Net::DNS to retrieve similar information: Read more... (2 kB) Hope that helps.	[reply] [d/l] [select]