xref: /linux/lib/build_OID_registry (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5) 
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
14use strict;
15
16my @names = ();
17my @oids = ();
18
19if ($#ARGV != 1) {
20    print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
21    exit(2);
22}
23
24#
25# Open the file to read from
26#
27open IN_FILE, "<$ARGV[0]" || die;
28while (<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, $2;
33    }
34}
35close IN_FILE || die;
36
37#
38# Open the files to write into
39#
40open C_FILE, ">$ARGV[1]" or die;
41print C_FILE "/*\n";
42print C_FILE " * Automatically generated by ", $0, ".  Do not edit\n";
43print 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#
49my @indices = ();
50my @lengths = ();
51my $total_length = 0;
52
53print "Compiling ", $#names + 1, " OIDs\n";
54
55for (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 += $size;
74}
75
76#
77# Emit the look-up-by-OID index table
78#
79print C_FILE "\n";
80if ($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}
85for (my $i = 0; $i <= $#names; $i++) {
86    print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
87}
88print C_FILE "\t[OID__NR] = ", $total_length, "\n";
89print C_FILE "};\n";
90
91#
92# Encode the OIDs
93#
94my @encoded_oids = ();
95
96for (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#
122my @hash_values = ();
123for (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#
139print C_FILE "\n";
140print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
141for (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}
148print C_FILE "};\n";
149
150#
151# Build the search index table (ordered by length then hash then content)
152#
153my @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#
174print C_FILE "\n";
175print C_FILE "static const struct {\n";
176print C_FILE "\tunsigned char hash;\n";
177if ($#names <= 255) {
178    print C_FILE "\tenum OID oid : 8;\n";
179} else {
180    print C_FILE "\tenum OID oid : 16;\n";
181}
182print C_FILE "} oid_search_table[OID__NR] = {\n";
183for (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}
192print 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#
209close C_FILE or die;
210