lib/build_OID_registry

   1 #!/usr/bin/perl -w
   2 #
   3 # Build a static ASN.1 Object Identified (OID) registry
   4 #
   5 # Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
   6 # Written by David Howells (dhowells@redhat.com)
   7 #
   8 # This program is free software; you can redistribute it and/or
   9 # modify it under the terms of the GNU General Public Licence
  10 # as published by the Free Software Foundation; either version
  11 # 2 of the Licence, or (at your option) any later version.
  12 #
  13
  14 use strict;
  15
  16 my @names = ();
  17 my @oids = ();
  18
  19 if ($#ARGV != 1) {
  20     print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
  21     exit(2);
  22 }
  23
  24 #
  25 # Open the file to read from
  26 #
  27 open IN_FILE, "<$ARGV[0]" || die;
  28 while (<IN_FILE>) {
  29     chomp;
  30     if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) {
  31         push @names, $1;
  32         push @oids, $2;
  33     }
  34 }
  35 close IN_FILE || die;
  36
  37 #
  38 # Open the files to write into
  39 #
  40 open C_FILE, ">$ARGV[1]" or die;
  41 print C_FILE "/*\n";
  42 print C_FILE " * Automatically generated by ", $0, ".  Do not edit\n";
  43 print C_FILE " */\n";
  44
  45 #
  46 # Split the data up into separate lists and also determine the lengths of the
  47 # encoded data arrays.
  48 #
  49 my @indices = ();
  50 my @lengths = ();
  51 my $total_length = 0;
  52
  53 for (my $i = 0; $i <= $#names; $i++) {
  54     my $name = $names[$i];
  55     my $oid = $oids[$i];
  56
  57     my @components = split(/[.]/, $oid);
  58
  59     # Determine the encoded length of this OID
  60     my $size = $#components;
  61     for (my $loop = 2; $loop <= $#components; $loop++) {
  62         my $c = $components[$loop];
  63
  64         # We will base128 encode the number
  65         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
  66         $tmp = int($tmp / 7);
  67         $size += $tmp;
  68     }
  69     push @lengths, $size;
  70     push @indices, $total_length;
  71     $total_length += $size;
  72 }
  73
  74 #
  75 # Emit the look-up-by-OID index table
  76 #
  77 print C_FILE "\n";
  78 if ($total_length <= 255) {
  79     print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
  80 } else {
  81     print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
  82 }
  83 for (my $i = 0; $i <= $#names; $i++) {
  84     print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
  85 }
  86 print C_FILE "\t[OID__NR] = ", $total_length, "\n";
  87 print C_FILE "};\n";
  88
  89 #
  90 # Encode the OIDs
  91 #
  92 my @encoded_oids = ();
  93
  94 for (my $i = 0; $i <= $#names; $i++) {
  95     my @octets = ();
  96
  97     my @components = split(/[.]/, $oids[$i]);
  98
  99     push @octets, $components[0] * 40 + $components[1];
 100
 101     for (my $loop = 2; $loop <= $#components; $loop++) {
 102         my $c = $components[$loop];
 103
 104         # Base128 encode the number
 105         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
 106         $tmp = int($tmp / 7);
 107
 108         for (; $tmp > 0; $tmp--) {
 109             push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
 110         }
 111         push @octets, $c & 0x7f;
 112     }
 113
 114     push @encoded_oids, \@octets;
 115 }
 116
 117 #
 118 # Create a hash value for each OID
 119 #
 120 my @hash_values = ();
 121 for (my $i = 0; $i <= $#names; $i++) {
 122     my @octets = @{$encoded_oids[$i]};
 123
 124     my $hash = $#octets;
 125     foreach (@octets) {
 126         $hash += $_ * 33;
 127     }
 128
 129     $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
 130
 131     push @hash_values, $hash & 0xff;
 132 }
 133
 134 #
 135 # Emit the OID data
 136 #
 137 print C_FILE "\n";
 138 print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
 139 for (my $i = 0; $i <= $#names; $i++) {
 140     my @octets = @{$encoded_oids[$i]};
 141     print C_FILE "\t";
 142     print C_FILE $_, ", " foreach (@octets);
 143     print C_FILE "\t// ", $names[$i];
 144     print C_FILE "\n";
 145 }
 146 print C_FILE "};\n";
 147
 148 #
 149 # Build the search index table (ordered by length then hash then content)
 150 #
 151 my @index_table = ( 0 .. $#names );
 152
 153 @index_table = sort {
 154     my @octets_a = @{$encoded_oids[$a]};
 155     my @octets_b = @{$encoded_oids[$b]};
 156
 157     return $hash_values[$a] <=> $hash_values[$b]
 158         if ($hash_values[$a] != $hash_values[$b]);
 159     return $#octets_a <=> $#octets_b
 160         if ($#octets_a != $#octets_b);
 161     for (my $i = $#octets_a; $i >= 0; $i--) {
 162         return $octets_a[$i] <=> $octets_b[$i]
 163             if ($octets_a[$i] != $octets_b[$i]);
 164     }
 165     return 0;
 166
 167 } @index_table;
 168
 169 #
 170 # Emit the search index and hash value table
 171 #
 172 print C_FILE "\n";
 173 print C_FILE "static const struct {\n";
 174 print C_FILE "\tunsigned char hash;\n";
 175 if ($#names <= 255) {
 176     print C_FILE "\tenum OID oid : 8;\n";
 177 } else {
 178     print C_FILE "\tenum OID oid : 16;\n";
 179 }
 180 print C_FILE "} oid_search_table[OID__NR] = {\n";
 181 for (my $i = 0; $i <= $#names; $i++) {
 182     my @octets = @{$encoded_oids[$index_table[$i]]};
 183     printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
 184            $i,
 185            $hash_values[$index_table[$i]],
 186            $names[$index_table[$i]]);
 187     printf C_FILE "%02x", $_ foreach (@octets);
 188     print C_FILE "\n";
 189 }
 190 print C_FILE "};\n";
 191
 192 #
 193 # Emit the OID debugging name table
 194 #
 195 #print C_FILE "\n";
 196 #print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
 197 #
 198 #for (my $i = 0; $i <= $#names; $i++) {
 199 #    print C_FILE "\t\"", $names[$i], "\",\n"
 200 #}
 201 #print C_FILE "\t\"Unknown-OID\"\n";
 202 #print C_FILE "};\n";
 203
 204 #
 205 # Polish off
 206 #
 207 close C_FILE or die;