#!/usr/bin/perl
#
# make /etc/services file from IANA web site.
# © TiChou <tichou@tichou.org>

use strict;

my $url = "http://www.iana.org/assignments/port-numbers";
my $ver = "1.0";
my $date = "2003/01/27";

use POSIX qw(strftime);

open(IANA,"lynx -dump -dont_wrap_pre $url|") || die "Can't connect to www.iana.org : $!\n";

print "# /etc/services, version $ver $date TiChou
#
# See \"man 5 services\" for more information.
#
# The Internet network services list (updated ".(strftime "%Y/%m/%d", localtime).")
#
# Port numbers are assigned by the IANA (Internet Assigned Numbers Authority),
# and their current policy is to assign both TCP and UDP protocols when
# assigning a port number. Therefore, most entries will have two entries, even
# for TCP only services.
#
# The latest IANA port assignments can be found on :
#
#	$url
#
# The port numbers are divided into three ranges :
#
# - The Well Known Ports are those from 0 through 1023,
# - The Registered Ports are those from 1024 through 49151,
# - The Dynamic and/or Private Ports are those from 49152 through 65535.
#
################################################################################
# WELL KNOWN PORT NUMBERS
#
# The Well Known Ports are assigned by the IANA and on most systems can only be
# used by system (or root) processes or by programs executed by privileged
# users.
#
# service-name	    port/protocol    aliases	comments
";

my ($port);

while (<IANA>) {
  s/\s+$//;
  if (/^(|#|[^\s#]+)\s+(\d+)(|-\d+|\/(tcp|udp|sctp))(\s+(#\s+)?(.*))?$/) {
    if ($2 == 1024 && $4 eq "tcp") {
      print "################################################################################
# REGISTERED PORT NUMBERS
#
# The Registered Ports are listed by the IANA and on most systems can be used by
# ordinary user processes or programs executed by ordinary users.
#
# service-name	    port/protocol    aliases	comments
";
    }
    print $1;
    print "\t"x(2-int(length($1)/8));
    print " "x(8-(int(length($1)/16)*length($1))%16-length($2));
    print "$2$3";
    print "\t\t\t# $7" if ($7);
    print "\n";
  } elsif (/^([^\s#]+)\s+(\d+)-(\d+)\/tcp(\s+(#\s+)?(.*))?$/) {
    for $port ($2..$3) {
      print $1;
      print "\t"x(2-int(length($1)/8));
      print " "x(8-(int(length($1)/16)*length($1))%16-length($port));
      print "$port/tcp";
      print "\t\t\t# $6" if ($6);
      print "\n";
      print $1;
      print "\t"x(2-int(length($1)/8));
      print " "x(8-(int(length($1)/16)*length($1))%16-length($port));
      print "$port/udp";
      print "\t\t\t# $6" if ($6);
      print "\n";
    }
  }
}

print "################################################################################
# DYNAMIC AND/OR PRIVATE PORTS
#
# service-name	    port/protocol    aliases	comments

# End of /etc/services.
";

close(IANA);