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 print "Compiling ", $#names + 1, " OIDs\n";
  54
  55 for (my $i = 0; $i <= $#names; $i++) {
  56     my $name = $names[$i];
  57     my $oid = $oids[$i];
  58
  59     my @components = split(/[.]/, $oid);
  60
  61     # Determine the encoded length of this OID
  62     my $size = $#components;
  63     for (my $loop = 2; $loop <= $#components; $loop++) {
  64         my $c = $components[$loop];
  65
  66         # We will base128 encode the number
  67         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
  68         $tmp = int($tmp / 7);
  69         $size += $tmp;
  70     }
  71     push @lengths, $size;
  72     push @indices, $total_length;
  73     $total_length += $size;
  74 }
  75
  76 #
  77 # Emit the look-up-by-OID index table
  78 #
  79 print C_FILE "\n";
  80 if ($total_length <= 255) {
  81     print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
  82 } else {
  83     print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
  84 }
  85 for (my $i = 0; $i <= $#names; $i++) {
  86     print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
  87 }
  88 print C_FILE "\t[OID__NR] = ", $total_length, "\n";
  89 print C_FILE "};\n";
  90
  91 #
  92 # Encode the OIDs
  93 #
  94 my @encoded_oids = ();
  95
  96 for (my $i = 0; $i <= $#names; $i++) {
  97     my @octets = ();
  98
  99     my @components = split(/[.]/, $oids[$i]);
 100
 101     push @octets, $components[0] * 40 + $components[1];
 102
 103     for (my $loop = 2; $loop <= $#components; $loop++) {
 104         my $c = $components[$loop];
 105
 106         # Base128 encode the number
 107         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
 108         $tmp = int($tmp / 7);
 109
 110         for (; $tmp > 0; $tmp--) {
 111             push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
 112         }
 113         push @octets, $c & 0x7f;
 114     }
 115
 116     push @encoded_oids, \@octets;
 117 }
 118
 119 #
 120 # Create a hash value for each OID
 121 #
 122 my @hash_values = ();
 123 for (my $i = 0; $i <= $#names; $i++) {
 124     my @octets = @{$encoded_oids[$i]};
 125
 126     my $hash = $#octets;
 127     foreach (@octets) {
 128         $hash += $_ * 33;
 129     }
 130
 131     $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
 132
 133     push @hash_values, $hash & 0xff;
 134 }
 135
 136 #
 137 # Emit the OID data
 138 #
 139 print C_FILE "\n";
 140 print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
 141 for (my $i = 0; $i <= $#names; $i++) {
 142     my @octets = @{$encoded_oids[$i]};
 143     print C_FILE "\t";
 144     print C_FILE $_, ", " foreach (@octets);
 145     print C_FILE "\t// ", $names[$i];
 146     print C_FILE "\n";
 147 }
 148 print C_FILE "};\n";
 149
 150 #
 151 # Build the search index table (ordered by length then hash then content)
 152 #
 153 my @index_table = ( 0 .. $#names );
 154
 155 @index_table = sort {
 156     my @octets_a = @{$encoded_oids[$a]};
 157     my @octets_b = @{$encoded_oids[$b]};
 158
 159     return $hash_values[$a] <=> $hash_values[$b]
 160         if ($hash_values[$a] != $hash_values[$b]);
 161     return $#octets_a <=> $#octets_b
 162         if ($#octets_a != $#octets_b);
 163     for (my $i = $#octets_a; $i >= 0; $i--) {
 164         return $octets_a[$i] <=> $octets_b[$i]
 165             if ($octets_a[$i] != $octets_b[$i]);
 166     }
 167     return 0;
 168
 169 } @index_table;
 170
 171 #
 172 # Emit the search index and hash value table
 173 #
 174 print C_FILE "\n";
 175 print C_FILE "static const struct {\n";
 176 print C_FILE "\tunsigned char hash;\n";
 177 if ($#names <= 255) {
 178     print C_FILE "\tenum OID oid : 8;\n";
 179 } else {
 180     print C_FILE "\tenum OID oid : 16;\n";
 181 }
 182 print C_FILE "} oid_search_table[OID__NR] = {\n";
 183 for (my $i = 0; $i <= $#names; $i++) {
 184     my @octets = @{$encoded_oids[$index_table[$i]]};
 185     printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
 186            $i,
 187            $hash_values[$index_table[$i]],
 188            $names[$index_table[$i]]);
 189     printf C_FILE "%02x", $_ foreach (@octets);
 190     print C_FILE "\n";
 191 }
 192 print C_FILE "};\n";
 193
 194 #
 195 # Emit the OID debugging name table
 196 #
 197 #print C_FILE "\n";
 198 #print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
 199 #
 200 #for (my $i = 0; $i <= $#names; $i++) {
 201 #    print C_FILE "\t\"", $names[$i], "\",\n"
 202 #}
 203 #print C_FILE "\t\"Unknown-OID\"\n";
 204 #print C_FILE "};\n";
 205
 206 #
 207 # Polish off
 208 #
 209 close C_FILE or die;