makezones

早期freebsd实现

#! /bin/perl

$version_number = "0.06a [22-Sep-93]";


########################################################################
#                           MAKEZONES                                  #
########################################################################

# Copyright (c), University of Cambridge, 1993.
# 
# The University retains the copyright and all other legal rights
# to this software and makes it available non-exclusively. All users
# must ensure that the software in all its derivations carries a
# copyright notice as above. No warranty is expressed or implied.

# This file is available for anonymous ftp from
# 
# ftp.cus.cam.ac.uk:/pub/software/programs/DNS/makezones
#
# Enquires to Philip Hazel <[e-mail]>.



########################################################################
# CONFIGURATION VARIABLES
#
# These are put at the top for ease of changing. See below for general
# specification of the script.


# Makezones checks the characters used in the components of names. Different
# sites may have different local standards in this respect. The variable
# $name_pattern is used to contain a regular expression pattern that
# matches valid components of domain names. Change it to suit your
# requirements. Note that:
#
#  (a) The variable contains only the pattern characters, NOT the delimiting
#      slashes.
#  (b) This pattern is for one component only, so should not contain things
#      that match full stops.
#  (c) The start and end of string metacharacters (^ and $) should not be
#      included; makezones uses this variable to build up a larger pattern
#      to match complete domain names, and it puts in ^ and $ itself.
#  (d) Because it is being constructed as a Perl string, any backslash
#      characters in the pattern must be doubled.

# This pattern specifies that names must start with a letter, contain only 
# letters, digits, and hyphens, and not end with a hyphen.

$name_pattern = '[a-zA-Z]([a-zA-Z\\-\\d]*[a-zA-Z\\d]+|)';

# Possible variations:
#
# $name_pattern = '[a-zA-Z\\d]([a-zA-Z\\-\\d]*[a-zA-Z\\d]+|)';  # digit at start
# $name_pattern = '[a-z]([a-z\\-\\d]*[a-z\\d]+|)';              # all lower case
#
# Note that, in addition to this, "*" is permitted as the first component of
# names on MX records, to allow MX wildcarding. Names for PTR records must
# always consist of four numeric components; $name_pattern is not used. Also,
# names on NS records may consist of numeric components - this is necessary
# in order to specify devolved reverse subzones.


# To disable the checking of new zone file lengths against the previous
# versions, set $opt_short = 1 here. This forces the -short option for
# all runs. 

$opt_short = 0;


# If you want fields in WKS records to be checked against the contents
# of a file for validity, then set $services to the name of the file, 
# and $grep to your favourite grep command. The values below will be
# typical. The program searches for the service name followed by a space
# or a tab at the start of a line. If you don't want this check, set
# $services to the null string.

$services = "/etc/services";
$grep = "/usr/bin/egrep";


# If you want makezones to output some commentary as it goes along,
# to let you know it is making some progress, then set the $chatty
# variable to 1.

$chatty = 1;



########################################################################
# UNIX DEPENDENCIES
#
# The Unix "date" command is used to obtain the current date and time
# in a particular format.
#
# Perl's "stat" function is used to obtain the lengths of files; this may
# differ for other operating systems.
#
# Anything else I've forgotten?



########################################################################
# 
# Makezones is a perl script for processing a source file for a DNS zone
# and producing the relevant operational DNS zone files. It does a lot of 
# checking to ensure that the data is not bad, and it also ensures that
# the forward and reverse zone information is in step.
#
# Makezones handles the updating of the serial number automatically. It
# does this by updating the SOURCE FILE before generating the zone files.
#                >>>>>      NB NB NB NB      <<<<<
# The source file therefore has to be writeable. Makezones insists that
# the format of the serial number be <year><month><day><version> and that
# the year be four digits long, so that this code will continue to work 
# after then end of 1999.
#
# Makezones handles Class B and Class C networks, because those are the
# ones that are around here in Cambridge, UK. It would not be hard to 
# extend it to handle a Class A if that were required.
#
# Because the file should normally be correct, makezones makes no attempt
# attempt to continue if it finds a serious error. It just reports it and 
# stops. However, syntax errors in the general records don't prevent it
# going on to check further records, so you can get more than one error
# message in a run. However, if it finds too many errors it says so, and
# gives up. "Too many" is currently more than ten.
#
# The input file looks like a normal DNS zone file, with the addition of
# the following rules, which impose additional restrictions. Some of these
# rules are to make it easy for makezones; some of them impose conventions
# that we use in Cambridge which might not be liked elsewhere. The code is
# well commented, and should be easy to modify.
#
#   . The class field ("IN") and the type fields ("A", "CNAME", etc.) must
#     be specified in upper case, as must "TCP" and "UDP" in WKS records.
#
#   . With the exception of the SOA & WKS records, all records must be 
#     complete on one line of input. That is, continuation is not supported
#     in general.
#
#   . The SOA record must be right at the start of the file, and must be
#     set up so that each numeric parameter is on a separate line. For
#     example:
#
#     @    IN    SOA    cus.cam.ac.uk. hostmaster.ucs.cam.ac.uk. (
#                             1993080601      ; Serial
#                             10800           ; Refresh 3 hours
#                             3600            ; Retry 1 hour
#                             604800          ; Expire after a week
#                             86400 )         ; Minimum ttl
#
#     Note that the serial number begins with the full year number, not just
#     the last two digits. The SOA record is expected to have the "IN" class
#     field; subsequent records may omit it.
#
#   . The NS records for the zone must appear at the top of the file, just
#     after the SOA record. These will be copied into the forward and the
#     reverse zone files. That is, the assumption is that the nameservers
#     are the same for the forward and reverse zones. These NS records must
#     NOT have anything in the name field. The copying stops on reaching
#     the first record with a name field or the first non-NS record.
#
#   . NS records must always refer to fully qualified names. Makezones checks
#     for the final dot, because it is so easy to overlook this.
#   
#   . Comments are not normally copied into the working zone files. They
#     can, however, be forced into them by the following syntax:
#     
#     ;F   copy this comment (without the F) into the forward file
#     ;R   copy this comment (without the R) into the reverse file
# 
#   . All records except PTR records are normally copied to the forward file. 
#     However, A records can be marked as "reverse only" by preceding them
#     with ">R " at the start. In this case, no A record is written to the
#     forward file, but a PTR record is constructed for the appropriate
#     reverse zone file. There should be exactly one space after the ">R";
#     three characters are removed from the start of the record. If ">R" is
#     followed by a tab, the tab is not removed (i.e. it acts as more than
#     one space).
#     
#   . PTR records and A records are the only ones used when generating the 
#     reverse zone files. "A" records can be marked "forwards only" by preced- 
#     ing them with ">F " at the start. This suppresses generation of a PTR 
#     record for the reverse zone. It does not, however, suppress the check that
#     the address is in one of the networks being handled (see next item for
#     external networks). If more than one A record has the same IP address,
#     then all but one must have the ">F " flag, to ensure that only one PTR
#     record is generated (for the canonical name). Again, there must be
#     exactly one space or a tab after ">F".
#     
#   . We want to be able to check that all IP addresses are in one of the 
#     networks that we are processing for. However, occasionally a record must
#     specify an external network (glue records are the prime example). Such 
#     records must be flagged by ">E " at their start to override the error 
#     that would otherwise occur. (They naturally won't get into any reverse 
#     zones.) The special local address 127.0.0.1 is recognized and treated as
#     though ">E " is always present. The ">E " flag can be used on WKS 
#     records as well as on A records.
#
#   . The name given for PTR records must be a complete, reversed IP address
#     that corresponds to one of the reverse zones. The network portion of
#     the "name" is removed when generating the PTR record for the reverse
#     zone. PTR records have to be used instead of A records flagged with
#     ">R " ("reverse only") when the name concerned is not in the domain
#     of the forward zone, because of the following rule.
#
#   . The names on all records must not end with . as we conventionally
#     specify them as partial domains for the forward zone. This means that,
#     if you want a record with the name of the zone as its domain, you must
#     use the "@" notation, which is supported.
#
#   . Makezones assumes that names consist of letters and digits, and start
#     with a letter. You can, however, override this by enclosing a name
#     in quotes. For example:
#
#     "3cpu"   A     134.232.45.69
#
#     I didn't want to allow these through normally, as in my zone they are
#     more likely to be typos. You can change the rules for what characters
#     are allowed in names (without quoting) by editing the variable 
#     $name_pattern (see under CONFIGURATION VARIABLES at the head of this 
#     file).
#
#   . CNAME records must point to fully qualified names. Makezones checks
#     that if a name appears on a CNAME, it does not appear on any other
#     record.
#
#   . MX records must point to fully qualified names.
#     
#
# Makezones is run by a command of the following form:
#
#   makezones [options] <source> <forward-zone> <forward-zone-file> \
#     [<reverse-zone-file>]*
#
# For example:
# 
#   makezones  DBsource  cam.ac.uk  db.cam  db.131.111  db.192.153.213
#   
# The source file is specified as the first argument. The second and third
# arguments specify the name of the zone and the file into which the records
# for that zone are to be written. The name is required so that fully
# qualified names can be generated in the reverse zone files. The remaining
# arguments specify the networks for which reverse zone files are to be 
# written, and the corresponding files. There need not be any if there are 
# no PTR or non-forwards-only A records in the source file. Each of these 
# final arguments is the name of a zone file. The first part of the name can 
# be anything you like - the only requirement is that the name must end with 
# a valid Class B or Class C network number.
#
# [This combining of network number and zone file name is done for convenience.
# To change makezones so that the numbers and file names are given as separate
# arguments would not be difficult; the changes would affect only the sub-
# routine that unpicks the arguments.]
#
# It is intended that makezones will normally be run as part of a "make" 
# sequence which will also install the files and reload the nameserver(s)
# after makezones has run successfully. Thus, the command to run it will
# normally be stored in a file and not typed each time.
# 
# The output files are actually written to temporary files whose names are the 
# same as the final ones with ".new" appended. If the processing succeeds,
# these files are renamed; if it fails, they are deleted.
#
# Normally no options are required. There is currently only one option:
#
#   -short   Used when a new zone file is more than 5% shorter than the 
#            previous version. If not given, the processing will fail if
#            a new file is that much shorter. This guards against the case
#            of accidental loss of large portions of the source file. Setting
#            -short disables the length checking for all zones. You need to
#            set this option if the previous versions of the files do not
#            exist. The script can be configured to default to -short; see
#            "configuration options" above.
# 
# The input file must be writable. The first thing the script does is to update 
# the serial number in the original file. This forms a permanent record and 
# ensures that all the created zones have the same number. The form of the
# serial number must be <year><month><day><sequence>, as in the example SOA
# record shown above. The code will continue to work after December 31, 1999.
# If more than 99 updates are done in one day, the failure is soft in that a 
# valid serial number is still generated, though it no longer contains that
# day's date.
#
# 
# Written by Philip Hazel <[e-mail]>
#   University Computing Service
#   Computer Laboratory
#   New Museums Site
#   Cambridge CB2 3QG 
#   United Kingdom
#   [phone]
#
# Started: August 1993
# Running: September 1993
#
# Update history:
#   0.03   07-Sep-93  I'd forgotten to allow TTLs on SOA records.
#   0.04   08-Sep-93  Allow comments before the SOA record.
#                     In several places, " " appeared in calls to split(),
#                       where "\s" should have appeared.
#                     Allow non-standard names in quotes. This lets in
#                       names like "3cpu" and "*.something".
#                     Treat tabs after >F etc as multiple spaces.
#                     Allow the name "@"; replace by zone name + dot.
#                     Allow omission of class field except on the SOA record.
#                     Check WKS address is in known network unless >E given.
#                     Fail broadcast addresses.
#   0.05   09-Sep-93  Use $name_pattern to check names.
#                     Permit "*" as first name component on MX records.
#   0.06   10-Sep-93  Failed if trailing spaces followed 127.0.0.1
#   0.06a  22-Sep-93  Updated the specification comments.




##################################################
#            Print error message and die         #
##################################################

# Ensure any temporary files are removed first. If reading the main file,
# $nline will be set non-zero and the current line will be in $_.

sub give_up {
do remove_temps();
print "\n** Makezones: $_[0]\n";
if ($nline > 0)
  {
  print "   At line $nline of $source_file:\n";
  print "   $_";  
  } 
die "** Processing abandoned.\n\n";
}



##################################################
#       Print error message and continue         #
##################################################

# After too many errors, give up. Setting $nline to 0
# stops it reflecting the input line again.

sub error {
print "\n** Makezones: $_[0]\n";
if ($nline > 0)
  {
  print "   At line $nline of $source_file:\n";
  print "   $_";  
  } 
if (++$errors > 10)
  { 
  do remove_temps();
  die "\n** Makezones: too many errors - processing abandoned.\n\n";  
  } 
}



##################################################
#       Print line to all reverse zone files     #
##################################################

sub print_reverse {
local($i);
for ($i = 0; $i < $rzone_count; $i++)
  {
  local($handle) = "REVERSE$i"; 
  print $handle $_[0];
  }
}   



##################################################
#            Unpick the argument list            #
##################################################

# Exit from the whole program on failure. 

sub unpick_args {
$rzone_count = 0;

# Handle options

while ($#ARGV >= 0 && substr($ARGV[0], 0, 1) eq '-')
  {
  if ($ARGV[0] eq "-short")  { $opt_short = 1; }
  else { do give_up("unknown option \"$ARGV[0]\""); } 
  shift ARGV;
  }
  
# Now we should be left with at least four arguments   

do give_up("at least three arguments are needed") if $#ARGV < 2;

# The first argument is the source file

$source_file = $ARGV[0]; shift ARGV;

# The second argument is the zone name; remove the trailing dot
# if present.

$zone_name = $ARGV[0]; shift ARGV;
chop($zone_name) if (substr($zone_name, -1, 1) eq ".");

# The third argument is the forwards zone file

$forward_file = $ARGV[0]; shift ARGV;

# We now have zero or more reverse zone files

while ($#ARGV >= 0)
  {
  local($rzone) = $ARGV[0]; shift ARGV;
  $rzone_file[$rzone_count] = $rzone;

  # Check explicitly for a class B or a class C number. I couldn't
  # find a cunning way of writing a single regular expression that
  # handled this. Anyway, we need to differentiate in order to check
  # the values.   
  
  local($a,$b,$c) = $rzone =~ /^.*\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
  
  if ("$a" eq "")
    {
    ($a,$b) = $rzone =~ /^.*\.(\d{1,3})\.(\d{1,3})$/;  
    do give_up("\"$rzone\" does not end with a class B or C ".
      "network number") if $a eq ""; 
    do give_up("bad class B network $a.$b") if ($a < 128 || $a > 191);
    $rzone_number[$rzone_count++] = ($a << 24) + ($b << 16); 
    } 
  else
    {
    do give_up("bad class C network $a.$b.$c") 
      if ($a < 192 || $a > 223);
    $rzone_number[$rzone_count++] = ($a << 24) + ($b << 16) + ($c << 8);    
    }  
  }  
}



##################################################  
#         Verify what we are going to do         #
##################################################

sub verify {
print "\nMakezones $version_number\n";
print "Generating DNS zone files for $zone_name from $source_file.\n";
print "  Forward zone file:  $forward_file\n";
printf "  Reverse zone file%s ", ($rzone_count == 1)? ": " : "s:";

if ($rzone_count > 0)
  {
  for ($i = 0; $i < $rzone_count; $i++)
    {
    print " "x22 if $i != 0;
    print "$rzone_file[$i]\n";