lib/build_OID_registry

   1 #!/usr/bin/perl -w
   2 # SPDX-License-Identifier: GPL-2.0-or-later
   3 #
   4 # Build a static ASN.1 Object Identified (OID) registry
   5 #
   6 # Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
   7 # Written by David Howells (dhowells@redhat.com)
   8 #
   9
  10 use strict;
  11
  12 my @names = ();
  13 my @oids = ();
  14
  15 if ($#ARGV != 1) {
  16     print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
  17     exit(2);
  18 }
  19
  20 #
  21 # Open the file to read from
  22 #
  23 open IN_FILE, "<$ARGV[0]" || die;
  24 while (<IN_FILE>) {
  25     chomp;
  26     if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) {
  27         push @names, $1;
  28         push @oids, $2;
  29     }
  30 }
  31 close IN_FILE || die;
  32
  33 #
  34 # Open the files to write into
  35 #
  36 open C_FILE, ">$ARGV[1]" or die;
  37 print C_FILE "/*\n";
  38 print C_FILE " * Automatically generated by ", $0, ".  Do not edit\n";
  39 print C_FILE " */\n";
  40
  41 #
  42 # Split the data up into separate lists and also determine the lengths of the
  43 # encoded data arrays.
  44 #
  45 my @indices = ();
  46 my @lengths = ();
  47 my $total_length = 0;
  48
  49 for (my $i = 0; $i <= $#names; $i++) {
  50     my $name = $names[$i];
  51     my $oid = $oids[$i];
  52
  53     my @components = split(/[.]/, $oid);
  54
  55     # Determine the encoded length of this OID
  56     my $size = $#components;
  57     for (my $loop = 2; $loop <= $#components; $loop++) {
  58         my $c = $components[$loop];
  59
  60         # We will base128 encode the number
  61         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
  62         $tmp = int($tmp / 7);
  63         $size += $tmp;
  64     }
  65     push @lengths, $size;
  66     push @indices, $total_length;
  67     $total_length += $size;
  68 }
  69
  70 #
  71 # Emit the look-up-by-OID index table
  72 #
  73 print C_FILE "\n";
  74 if ($total_length <= 255) {
  75     print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
  76 } else {
  77     print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
  78 }
  79 for (my $i = 0; $i <= $#names; $i++) {
  80     print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
  81 }
  82 print C_FILE "\t[OID__NR] = ", $total_length, "\n";
  83 print C_FILE "};\n";
  84
  85 #
  86 # Encode the OIDs
  87 #
  88 my @encoded_oids = ();
  89
  90 for (my $i = 0; $i <= $#names; $i++) {
  91     my @octets = ();
  92
  93     my @components = split(/[.]/, $oids[$i]);
  94
  95     push @octets, $components[0] * 40 + $components[1];
  96
  97     for (my $loop = 2; $loop <= $#components; $loop++) {
  98         my $c = $components[$loop];
  99
 100         # Base128 encode the number
 101         my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
 102         $tmp = int($tmp / 7);
 103
 104         for (; $tmp > 0; $tmp--) {
 105             push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
 106         }
 107         push @octets, $c & 0x7f;
 108     }
 109
 110     push @encoded_oids, \@octets;
 111 }
 112
 113 #
 114 # Create a hash value for each OID
 115 #
 116 my @hash_values = ();
 117 for (my $i = 0; $i <= $#names; $i++) {
 118     my @octets = @{$encoded_oids[$i]};
 119
 120     my $hash = $#octets;
 121     foreach (@octets) {
 122         $hash += $_ * 33;
 123     }
 124
 125     $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
 126
 127     push @hash_values, $hash & 0xff;
 128 }
 129
 130 #
 131 # Emit the OID data
 132 #
 133 print C_FILE "\n";
 134 print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
 135 for (my $i = 0; $i <= $#names; $i++) {
 136     my @octets = @{$encoded_oids[$i]};
 137     print C_FILE "\t";
 138     print C_FILE $_, ", " foreach (@octets);
 139     print C_FILE "\t// ", $names[$i];
 140     print C_FILE "\n";
 141 }
 142 print C_FILE "};\n";
 143
 144 #
 145 # Build the search index table (ordered by length then hash then content)
 146 #
 147 my @index_table = ( 0 .. $#names );
 148
 149 @index_table = sort {
 150     my @octets_a = @{$encoded_oids[$a]};
 151     my @octets_b = @{$encoded_oids[$b]};
 152
 153     return $hash_values[$a] <=> $hash_values[$b]
 154         if ($hash_values[$a] != $hash_values[$b]);
 155     return $#octets_a <=> $#octets_b
 156         if ($#octets_a != $#octets_b);
 157     for (my $i = $#octets_a; $i >= 0; $i--) {
 158         return $octets_a[$i] <=> $octets_b[$i]
 159             if ($octets_a[$i] != $octets_b[$i]);
 160     }
 161     return 0;
 162
 163 } @index_table;
 164
 165 #
 166 # Emit the search index and hash value table
 167 #
 168 print C_FILE "\n";
 169 print C_FILE "static const struct {\n";
 170 print C_FILE "\tunsigned char hash;\n";
 171 if ($#names <= 255) {
 172     print C_FILE "\tenum OID oid : 8;\n";
 173 } else {
 174     print C_FILE "\tenum OID oid : 16;\n";
 175 }
 176 print C_FILE "} oid_search_table[OID__NR] = {\n";
 177 for (my $i = 0; $i <= $#names; $i++) {
 178     my @octets = @{$encoded_oids[$index_table[$i]]};
 179     printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
 180            $i,
 181            $hash_values[$index_table[$i]],
 182            $names[$index_table[$i]]);
 183     printf C_FILE "%02x", $_ foreach (@octets);
 184     print C_FILE "\n";
 185 }
 186 print C_FILE "};\n";
 187
 188 #
 189 # Emit the OID debugging name table
 190 #
 191 #print C_FILE "\n";
 192 #print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
 193 #
 194 #for (my $i = 0; $i <= $#names; $i++) {
 195 #    print C_FILE "\t\"", $names[$i], "\",\n"
 196 #}
 197 #print C_FILE "\t\"Unknown-OID\"\n";
 198 #print C_FILE "};\n";
 199
 200 #
 201 # Polish off
 202 #
 203 close C_FILE or die;