lib: add oid registry utility

Imported from linux kernel v5.3:
 build_OID_registry without changes
 oid_registry.h without changes
 oid_registry.c with changes marked as __UBOOT__

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

lib/oid_registry.c

@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* ASN.1 Object identifier (OID) registry
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifdef __UBOOT__
+#include <linux/compat.h>
+#else
+#include <linux/module.h>
+#include <linux/export.h>
+#endif
+#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;
+		}
+
+		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)
+		goto bad;
+
+	n = *v++;
+	ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
+	if (count >= bufsize)
+		return -ENOBUFS;
+	buffer += count;
+	bufsize -= count;
+
+	while (v < end) {
+		num = 0;
+		n = *v++;
+		if (!(n & 0x80)) {
+			num = n;
+		} else {
+			num = n & 0x7f;
+			do {
+				if (v >= end)
+					goto bad;
+				n = *v++;
+				num <<= 7;
+				num |= n & 0x7f;
+			} while (n & 0x80);
+		}
+		ret += count = snprintf(buffer, bufsize, ".%lu", num);
+		if (count >= bufsize)
+			return -ENOBUFS;
+		buffer += count;
+		bufsize -= count;
+	}
+
+	return ret;
+
+bad:
+	snprintf(buffer, bufsize, "(bad)");
+	return -EBADMSG;
+}
+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);