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-rw-r--r--lib/oid_registry.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/lib/oid_registry.c b/lib/oid_registry.c
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--- /dev/null
+++ b/lib/oid_registry.c
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+/* 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 <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/bug.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);
+
+/*
+ * sprint_OID - Print an Object Identifier into a buffer
+ * @data: The encoded OID to print
+ * @datasize: The size of the encoded OID
+ * @buffer: The buffer to render into
+ * @bufsize: The size of the buffer
+ *
+ * The OID is rendered into the buffer in "a.b.c.d" format and the number of
+ * bytes is returned. -EBADMSG is returned if the data could not be intepreted
+ * and -ENOBUFS if the buffer was too small.
+ */
+int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize)
+{
+ const unsigned char *v = data, *end = v + datasize;
+ unsigned long num;
+ unsigned char n;
+ size_t ret;
+ int count;
+
+ if (v >= end)
+ return -EBADMSG;
+
+ n = *v++;
+ ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
+ buffer += count;
+ bufsize -= count;
+ if (bufsize == 0)
+ return -ENOBUFS;
+
+ while (v < end) {
+ num = 0;
+ n = *v++;
+ if (!(n & 0x80)) {
+ num = n;
+ } else {
+ num = n & 0x7f;
+ do {
+ if (v >= end)
+ return -EBADMSG;
+ n = *v++;
+ num <<= 7;
+ num |= n & 0x7f;
+ } while (n & 0x80);
+ }
+ ret += count = snprintf(buffer, bufsize, ".%lu", num);
+ buffer += count;
+ bufsize -= count;
+ if (bufsize == 0)
+ return -ENOBUFS;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sprint_oid);
+
+/**
+ * sprint_OID - Print an Object Identifier into a buffer
+ * @oid: The OID to print
+ * @buffer: The buffer to render into
+ * @bufsize: The size of the buffer
+ *
+ * The OID is rendered into the buffer in "a.b.c.d" format and the number of
+ * bytes is returned.
+ */
+int sprint_OID(enum OID oid, char *buffer, size_t bufsize)
+{
+ int ret;
+
+ BUG_ON(oid >= OID__NR);
+
+ ret = sprint_oid(oid_data + oid_index[oid],
+ oid_index[oid + 1] - oid_index[oid],
+ buffer, bufsize);
+ BUG_ON(ret == -EBADMSG);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sprint_OID);