5 files changed, 320 insertions, 1 deletions

diff --git a/lib/.gitignore b/lib/.gitignore
index 3bef1ea94c99..09aae85418ab 100644
--- a/lib/.gitignore
+++ b/lib/.gitignore
@@ -3,4 +3,4 @@
 #
 gen_crc32table
 crc32table.h
-
+oid_registry_data.c
diff --git a/lib/Kconfig b/lib/Kconfig
index bb94c1ba616a..4b31a46fb307 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -396,4 +396,9 @@ config SIGNATURE
 config LIBFDT
         bool
 
+config OID_REGISTRY
+        tristate
+        help
+          Enable fast lookup object identifier registry.
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 42d283edc4d3..b0428960939f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -150,3 +150,19 @@ quiet_cmd_crc32 = GEN     $@
 
 $(obj)/crc32table.h: $(obj)/gen_crc32table
         $(call cmd,crc32)
+
+#
+# Build a fast OID lookip registry from include/linux/oid_registry.h
+#
+obj-$(CONFIG_OID_REGISTRY) += oid_registry.o
+
+$(obj)/oid_registry.c: $(obj)/oid_registry_data.c
+
+$(obj)/oid_registry_data.c: $(srctree)/include/linux/oid_registry.h \
+                            $(src)/build_OID_registry
+        $(call cmd,build_OID_registry)
+
+quiet_cmd_build_OID_registry = GEN     $@
+      cmd_build_OID_registry = perl $(srctree)/$(src)/build_OID_registry $< $@
+
+clean-files     += oid_registry_data.c
diff --git a/lib/build_OID_registry b/lib/build_OID_registry
new file mode 100755
index 000000000000..dfbdaab81bc8
--- /dev/null
+++ b/lib/build_OID_registry
@@ -0,0 +1,209 @@
+#!/usr/bin/perl -w
+#
+# Build a static ASN.1 Object Identified (OID) registry
+#
+# Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+# Written by David Howells (dhowells@redhat.com)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public Licence
+# as published by the Free Software Foundation; either version
+# 2 of the Licence, or (at your option) any later version.
+#
+
+use strict;
+
+my @names = ();
+my @oids = ();
+
+if ($#ARGV != 1) {
+    print STDERR "Format: ", $0, " <in-h-file> <out-c-file>\n";
+    exit(2);
+}
+
+#
+# Open the file to read from
+#
+open IN_FILE, "<$ARGV[0]" || die;
+while (<IN_FILE>) {
+    chomp;
+    if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) {
+        push @names, $1;
+        push @oids, $2;
+    }
+}
+close IN_FILE || die;
+
+#
+# Open the files to write into
+#
+open C_FILE, ">$ARGV[1]" or die;
+print C_FILE "/*\n";
+print C_FILE " * Automatically generated by ", $0, ".  Do not edit\n";
+print C_FILE " */\n";
+
+#
+# Split the data up into separate lists and also determine the lengths of the
+# encoded data arrays.
+#
+my @indices = ();
+my @lengths = ();
+my $total_length = 0;
+
+print "Compiling ", $#names + 1, " OIDs\n";
+
+for (my $i = 0; $i <= $#names; $i++) {
+    my $name = $names[$i];
+    my $oid = $oids[$i];
+
+    my @components = split(/[.]/, $oid);
+
+    # Determine the encoded length of this OID
+    my $size = $#components;
+    for (my $loop = 2; $loop <= $#components; $loop++) {
+        my $c = $components[$loop];
+
+        # We will base128 encode the number
+        my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
+        $tmp = int($tmp / 7);
+        $size += $tmp;
+    }
+    push @lengths, $size;
+    push @indices, $total_length;
+    $total_length += $size;
+}
+
+#
+# Emit the look-up-by-OID index table
+#
+print C_FILE "\n";
+if ($total_length <= 255) {
+    print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n";
+} else {
+    print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n";
+}
+for (my $i = 0; $i <= $#names; $i++) {
+    print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n"
+}
+print C_FILE "\t[OID__NR] = ", $total_length, "\n";
+print C_FILE "};\n";
+
+#
+# Encode the OIDs
+#
+my @encoded_oids = ();
+
+for (my $i = 0; $i <= $#names; $i++) {
+    my @octets = ();
+
+    my @components = split(/[.]/, $oids[$i]);
+
+    push @octets, $components[0] * 40 + $components[1];
+
+    for (my $loop = 2; $loop <= $#components; $loop++) {
+        my $c = $components[$loop];
+
+        # Base128 encode the number
+        my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
+        $tmp = int($tmp / 7);
+
+        for (; $tmp > 0; $tmp--) {
+            push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
+        }
+        push @octets, $c & 0x7f;
+    }
+
+    push @encoded_oids, \@octets;
+}
+
+#
+# Create a hash value for each OID
+#
+my @hash_values = ();
+for (my $i = 0; $i <= $#names; $i++) {
+    my @octets = @{$encoded_oids[$i]};
+
+    my $hash = $#octets;
+    foreach (@octets) {
+        $hash += $_ * 33;
+    }
+
+    $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash);
+
+    push @hash_values, $hash & 0xff;
+}
+
+#
+# Emit the OID data
+#
+print C_FILE "\n";
+print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n";
+for (my $i = 0; $i <= $#names; $i++) {
+    my @octets = @{$encoded_oids[$i]};
+    print C_FILE "\t";
+    print C_FILE $_, ", " foreach (@octets);
+    print C_FILE "\t// ", $names[$i];
+    print C_FILE "\n";
+}
+print C_FILE "};\n";
+
+#
+# Build the search index table (ordered by length then hash then content)
+#
+my @index_table = ( 0 .. $#names );
+
+@index_table = sort {
+    my @octets_a = @{$encoded_oids[$a]};
+    my @octets_b = @{$encoded_oids[$b]};
+
+    return $hash_values[$a] <=> $hash_values[$b]
+        if ($hash_values[$a] != $hash_values[$b]);
+    return $#octets_a <=> $#octets_b
+        if ($#octets_a != $#octets_b);
+    for (my $i = $#octets_a; $i >= 0; $i--) {
+        return $octets_a[$i] <=> $octets_b[$i]
+            if ($octets_a[$i] != $octets_b[$i]);
+    }
+    return 0;
+
+} @index_table;
+
+#
+# Emit the search index and hash value table
+#
+print C_FILE "\n";
+print C_FILE "static const struct {\n";
+print C_FILE "\tunsigned char hash;\n";
+if ($#names <= 255) {
+    print C_FILE "\tenum OID oid : 8;\n";
+} else {
+    print C_FILE "\tenum OID oid : 16;\n";
+}
+print C_FILE "} oid_search_table[OID__NR] = {\n";
+for (my $i = 0; $i <= $#names; $i++) {
+    my @octets = @{$encoded_oids[$index_table[$i]]};
+    printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ",
+           $i,
+           $hash_values[$index_table[$i]],
+           $names[$index_table[$i]]);
+    printf C_FILE "%02x", $_ foreach (@octets);
+    print C_FILE "\n";
+}
+print C_FILE "};\n";
+
+#
+# Emit the OID debugging name table
+#
+#print C_FILE "\n";
+#print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n";
+#
+#for (my $i = 0; $i <= $#names; $i++) {
+#    print C_FILE "\t\"", $names[$i], "\",\n"
+#}
+#print C_FILE "\t\"Unknown-OID\"\n";
+#print C_FILE "};\n";
+
+#
+# Polish off
+#
+close C_FILE or die;
diff --git a/lib/oid_registry.c b/lib/oid_registry.c
new file mode 100644
index 000000000000..33cfd171f627
--- /dev/null
+++ b/lib/oid_registry.c
@@ -0,0 +1,89 @@
+/* ASN.1 Object identifier (OID) registry
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/export.h>
+#include <linux/oid_registry.h>
+#include "oid_registry_data.c"
+
+/**
+ * look_up_OID - Find an OID registration for the specified data
+ * @data: Binary representation of the OID
+ * @datasize: Size of the binary representation
+ */
+enum OID look_up_OID(const void *data, size_t datasize)
+{
+        const unsigned char *octets = data;
+        enum OID oid;
+        unsigned char xhash;
+        unsigned i, j, k, hash;
+        size_t len;
+
+        /* Hash the OID data */
+        hash = datasize - 1;
+
+        for (i = 0; i < datasize; i++)
+                hash += octets[i] * 33;
+        hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash;
+        hash &= 0xff;
+
+        /* Binary search the OID registry.  OIDs are stored in ascending order
+         * of hash value then ascending order of size and then in ascending
+         * order of reverse value.
+         */
+        i = 0;
+        k = OID__NR;
+        while (i < k) {
+                j = (i + k) / 2;
+
+                xhash = oid_search_table[j].hash;
+                if (xhash > hash) {
+                        k = j;
+                        continue;
+                }
+                if (xhash < hash) {
+                        i = j + 1;
+                        continue;
+                }
+
+                oid = oid_search_table[j].oid;
+                len = oid_index[oid + 1] - oid_index[oid];
+                if (len > datasize) {
+                        k = j;
+                        continue;
+                }
+                if (len < datasize) {
+                        i = j + 1;
+                        continue;
+                }
+
+                /* Variation is most likely to be at the tail end of the
+                 * OID, so do the comparison in reverse.
+                 */
+                while (len > 0) {
+                        unsigned char a = oid_data[oid_index[oid] + --len];
+                        unsigned char b = octets[len];
+                        if (a > b) {
+                                k = j;
+                                goto next;
+                        }
+                        if (a < b) {
+                                i = j + 1;
+                                goto next;
+                        }
+                }
+                return oid;
+        next:
+                ;
+        }
+
+        return OID__NR;
+}
+EXPORT_SYMBOL_GPL(look_up_OID);