FHEM/fhem-mirror
2
0
Fork 0
mirror of https://github.com/fhem/fhem-mirror.git synced 2025-01-31 18:59:33 +00:00
Code Issues Releases Wiki Activity

HttpUtils.pm: Parse non-compressed DNS answer (Forum #53309)

Browse Source 
git-svn-id: https://svn.fhem.de/fhem/trunk@11935 2b470e98-0d58-463d-a4d8-8e2adae1ed80
This commit is contained in:
rudolfkoenig 2016-08-10 09:09:03 +00:00
parent d5a37052a2
commit ea1d8e37ba
1 changed files with 16 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fhem/FHEM/HttpUtils.pm
View File

@ -106,16 +106,28 @@ HttpUtils_File($)
sub ip2str($) { return sprintf("%d.%d.%d.%d", unpack("C*", shift)); }
# http://www.ccs.neu.edu/home/amislove/teaching/cs4700/fall09/handouts/project1-primer.pdf
my %HU_dnsCache;
sub
HttpUtils_dnsParse($$)
{
my ($a, $ql) = @_;
my ($a, $ql) = @_; # $ql: avoid hardcoding query length
return "wrong message ID" if(unpack("H*",substr($a,0,2)) ne "7072");
while(length($a) >= $ql+16) {
return (undef, substr($a,$ql+12,4), unpack("N",substr($a,$ql+6,4)))
if(unpack("N",substr($a,$ql+2,4)) == 0x10001);
$ql += 12+unpack("n",substr($a,$ql+10));
my $l = unpack("C",substr($a,$ql, 1));
if(($l & 0xC0) == 0xC0) { # DNS packed compression
$ql += 2;
} else {
while($l != 0) {
$ql += $l+1;
$l = unpack("C",substr($a,$ql,2));
}
$ql++;
}
return (undef, substr($a,$ql+10,4), unpack("N",substr($a,$ql+4,4)))
if(unpack("N",substr($a,$ql,4)) == 0x10001);
$ql += 10+unpack("n",substr($a,$ql+8)) if(length($a) >= $ql+10);
}
return "No A record found";
}