My solution is similar to NetWallah's, but it allows subnet customization in the %special_subnets data, rather than in code.

Since you are pre-pending '0x' to $count, I added code to convert $count to hex first; ignore if inappropriate.

Working, lightly tested code: 

my $DEV = 'dev eth1';
my $count = 500;

my %special_subnets = (
   6 => [ 0, 1, 2],
  17 => [ 0, 1],
  19 => [ 0, 1, 2],
);

foreach my $oct1 ( 10 )  {
  foreach my $oct2 ( 1 .. 22 )  {
    my $third_octets_aref = $special_subnets{$oct2} || [ 0 ];
    foreach my $oct3 ( @{ $third_octets_aref } )  {
      foreach my $oct4 ( 1 .. 254 )  { # 253 ??
        print HTB generate_rule( $DEV, $count, $oct1, $oct2, $oct3, $o
+ct4 );
        $count++;
      }
    }
  }
}

sub generate_rule {
  my ( $dev, $count, @octets ) = @_;

  my $ip = join '.', @octets;
#  my $countx = '0x' . $count;
  my $countx = sprintf '0x%04x', $count;

  return <<"END_RULE";
  
 class  add $dev parent 1:7 classid 1:$countx rate 4kbit ceil 512Kbit 
+burst 4kbit prio 1 quantum 2000
 filter add $dev protocol ip parent 1:0 prio 1 u32 match ip dst $ip/32
+ match ip src 0.0.0.0/0 flowid 1:$countx
 qdisc  add $dev parent 1:$countx handle $countx: pfifo limit 5
END_RULE
}

[download]

In reply to Re: IP generation algorithm problem by Util
in thread IP generation algorithm (tc) by giany

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.