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