1 files changed, 170 insertions, 0 deletions

diff --git a/lib/oid_registry.c b/lib/oid_registry.c
new file mode 100644
index 000000000000..d8de11f45908
--- /dev/null
+++ b/lib/oid_registry.c
@@ -0,0 +1,170 @@
+/* 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);