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

I have this problem generating a file ..
I have 22 clases and foreach ip i have to generate those 3 lines. The problem is that from those 22 clases i have 3 clases..(6,17,19) that have 1 or 2 subclasses.. and the ip must be smth like 10.x.1.y or 10.x.2.y. So for 3 I have exceptions..

How can I fix this problem?

This is the code I wrote for all 22 classes with no exceptions.
my $DEV = "dev eth1";
my $count=500;
for ($x = 1;$x < 23;$x++)  {
for ($y = 1;$y < 255;$y++) {

  print HTB "\n class add $DEV parent 1:7 classid 1:0x".$count." rate 
+4kbit ceil 512Kbit burst 4kbit prio 1 quantum 2000\n";
  print HTB " filter add $DEV protocol ip parent 1:0 prio 1 u32 match 
+ip dst 10.".$x.".0.".$y."/32 match ip src 0.0.0.0/0 flowid 1:0
x".$count."\n";
  print HTB " qdisc add $DEV parent 1:0x".$count." handle 0x".$count++
+.": pfifo limit 5\n";
}
}

[download]

2006-02-10 Retitled by planetscape, as per Monastery guidelines
Original title: 'Generate problem'

Replies are listed 'Best First'.
Re: IP generation algorithm problem
by NetWallah (Canon) on Feb 09, 2006 at 22:04 UTC
    Here is an outline, to get you started .. 
    use strict;

my %exception_second_octet = map {$_=> "Put Subclass Info here"} qw( 6
+  17  19);

for my $second_octet (1..23){
    if ($exception_second_octet{$second_octet}){
        # Put Subclass generation code here
    } else {
        for my $fourth_octet(1..255){
           my $generated_ip = "10.$second_octet.0.$fourth_octet/32";
           # Do whatever else ...
        }
    }
}

    [download]
    UPDATE: Shouldn't your fourth octet be limited to 253, to avoid the multicast and broadcast addresses for a class-C network ?

         "For every complex problem, there is a simple answer ... and it is wrong." --H.L. Mencken

[reply]
[d/l]
Re: IP generation algorithm problem
by Util (Priest) on Feb 10, 2006 at 14:54 UTC

    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]

[reply]
[d/l]
[select]
      There seems to be a problem and I can`t figure it out.. This is the code: 
      use strict;
use warnings;

system('/usr/bin/clear');
print "\n\n";
open(IN1,"/root/work/htb/banner");
open(HTB,">/root/work/htb/full");
my @head_htb=<IN1>;
close(IN1);
print HTB "@head_htb";

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, $oct
+3, $oct4 );
             $count++;
             }
        }
   }
}

sub generate_rule {
my ( $dev, $count, @octets ) = @_;
my $ip = join '.', @octets;
#my $countx = '0x' . $count;
my $countx = sprintf '0x%04x', $count;

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

 }
close (HTB);

      [download]
      And the error is : 
      Can't find string terminator "RULE" anywhere before EOF at genhtb.pl l
+ine 44.

      [download]
      As far as I know a ENTER must be pressed after RULE so perl can reconize it as a string terminator..
[reply]
[d/l]
[select]
        I`ve fixed : there must be no space in front of RULE. Thx for help!
[reply]

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