projects/linux·blob master · refs

218 lines · 5.0 KiB

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 ([email protected])
8#
9
10use strict;
11use Cwd qw(abs_path);
12
13my @names = ();
14my @oids = ();
15
16if ($#ARGV != 1) {
17 print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
18 exit(2);
19}
20
21my $abs_srctree = abs_path($ENV{'srctree'});
22
23#
24# Open the file to read from
25#
26open IN_FILE, "<$ARGV[0]" || die;
27while (<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, $2;
32 }
33}
34close IN_FILE || die;
35
36#
37# Open the files to write into
38#
39open C_FILE, ">$ARGV[1]" or die;
40print C_FILE "/*\n";
41my $scriptname = $0;
42$scriptname =~ s#^\Q$abs_srctree/\E##;
43print C_FILE " * Automatically generated by ", $scriptname, ". Do not edit\n";
44print 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#
50my @indices = ();
51my @lengths = ();
52my $total_length = 0;
53
54for (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 $ENV{'BC_LINE_LENGTH'} = "0";
64 my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`;
65 chomp($c);
66
67 # We will base128 encode the number
68 my $tmp = length($c) - 1;
69 $tmp = int($tmp / 7);
70 $size += $tmp;
71 }
72 push @lengths, $size;
73 push @indices, $total_length;
74 $total_length += $size;
75}
76
77#
78# Emit the look-up-by-OID index table
79#
80print C_FILE "\n";
81if ($total_length <= 255) {
82 print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
83} else {
84 print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
85}
86for (my $i = 0; $i <= $#names; $i++) {
87 print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
88}
89print C_FILE "\t[OID__NR] = ", $total_length, "\n";
90print C_FILE "};\n";
91
92#
93# Encode the OIDs
94#
95my @encoded_oids = ();
96
97for (my $i = 0; $i <= $#names; $i++) {
98 my @octets = ();
99
100 my @components = split(/[.]/, $oids[$i]);
101
102 push @octets, $components[0] * 40 + $components[1];
103
104 for (my $loop = 2; $loop <= $#components; $loop++) {
105 # get the base 2 representation of the component
106 $ENV{'BC_LINE_LENGTH'} = "0";
107 my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`;
108 chomp($c);
109
110 my $tmp = length($c) - 1;
111 $tmp = int($tmp / 7);
112
113 # zero pad upto length multiple of 7
114 $c = substr("0000000", 0, ($tmp + 1) * 7 - length($c)).$c;
115
116 # Base128 encode the number
117 for (my $j = 0; $j < $tmp; $j++) {
118 my $b = oct("0b".substr($c, $j * 7, 7));
119
120 push @octets, $b | 0x80;
121 }
122 push @octets, oct("0b".substr($c, $tmp * 7, 7));
123 }
124
125 push @encoded_oids, \@octets;
126}
127
128#
129# Create a hash value for each OID
130#
131my @hash_values = ();
132for (my $i = 0; $i <= $#names; $i++) {
133 my @octets = @{$encoded_oids[$i]};
134
135 my $hash = $#octets;
136 foreach (@octets) {
137 $hash += $_ * 33;
138 }
139
140 $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
141
142 push @hash_values, $hash & 0xff;
143}
144
145#
146# Emit the OID data
147#
148print C_FILE "\n";
149print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
150for (my $i = 0; $i <= $#names; $i++) {
151 my @octets = @{$encoded_oids[$i]};
152 print C_FILE "\t";
153 print C_FILE $_, ", " foreach (@octets);
154 print C_FILE "\t// ", $names[$i];
155 print C_FILE "\n";
156}
157print C_FILE "};\n";
158
159#
160# Build the search index table (ordered by length then hash then content)
161#
162my @index_table = ( 0 .. $#names );
163
164@index_table = sort {
165 my @octets_a = @{$encoded_oids[$a]};
166 my @octets_b = @{$encoded_oids[$b]};
167
168 return $hash_values[$a] <=> $hash_values[$b]
169 if ($hash_values[$a] != $hash_values[$b]);
170 return $#octets_a <=> $#octets_b
171 if ($#octets_a != $#octets_b);
172 for (my $i = $#octets_a; $i >= 0; $i--) {
173 return $octets_a[$i] <=> $octets_b[$i]
174 if ($octets_a[$i] != $octets_b[$i]);
175 }
176 return 0;
177
178} @index_table;
179
180#
181# Emit the search index and hash value table
182#
183print C_FILE "\n";
184print C_FILE "static const struct {\n";
185print C_FILE "\tunsigned char hash;\n";
186if ($#names <= 255) {
187 print C_FILE "\tenum OID oid : 8;\n";
188} else {
189 print C_FILE "\tenum OID oid : 16;\n";
190}
191print C_FILE "} oid_search_table[OID__NR] = {\n";
192for (my $i = 0; $i <= $#names; $i++) {
193 my @octets = @{$encoded_oids[$index_table[$i]]};
194 printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
195 $i,
196 $hash_values[$index_table[$i]],
197 $names[$index_table[$i]]);
198 printf C_FILE "%02x", $_ foreach (@octets);
199 print C_FILE "\n";
200}
201print C_FILE "};\n";
202
203#
204# Emit the OID debugging name table
205#
206#print C_FILE "\n";
207#print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
208#
209#for (my $i = 0; $i <= $#names; $i++) {
210# print C_FILE "\t\"", $names[$i], "\",\n"
211#}
212#print C_FILE "\t\"Unknown-OID\"\n";
213#print C_FILE "};\n";
214
215#
216# Polish off
217#
218close C_FILE or die;