linux-imx

/* 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/module.h>

#include <linux/export.h>

#include <linux/oid_registry.h>

#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/bug.h>

#include "oid_registry_data.c"

​

MODULE_DESCRIPTION("OID Registry");

MODULE_AUTHOR("Red Hat, Inc.");

MODULE_LICENSE("GPL");

​

/**

 * 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;

        }

​