lib/oid_registry.c

Source file repositories/reference/linux-study-clean/lib/oid_registry.c

File Facts

System
Linux kernel
Corpus path
lib/oid_registry.c
Extension
.c
Size
3979 bytes
Lines
176
Domain
Kernel Services
Bucket
lib
Inferred role
Kernel Services: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

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);

/**
 * parse_OID - Parse an OID from a bytestream
 * @data: Binary representation of the header + OID
 * @datasize: Size of the binary representation
 * @oid: Pointer to oid to return result
 *
 * Parse an OID from a bytestream that holds the OID in the format
 * ASN1_OID | length | oid. The length indicator must equal to datasize - 2.
 * -EBADMSG is returned if the bytestream is too short.
 */
int parse_OID(const void *data, size_t datasize, enum OID *oid)
{
	const unsigned char *v = data;

	/* we need 2 bytes of header and at least 1 byte for oid */
	if (datasize < 3 || v[0] != ASN1_OID || v[1] != datasize - 2)
		return -EBADMSG;

	*oid = look_up_OID(data + 2, datasize - 2);
	return 0;
}
EXPORT_SYMBOL_GPL(parse_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 interpreted
 * 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++;

Annotation

Implementation Notes