xref: /linux/tools/lib/bpf/nlattr.h (revision 9a379e77033f02c4a071891afdf0f0a01eff8ccb)
1 /* SPDX-License-Identifier: LGPL-2.1 */
2 
3 /*
4  * NETLINK      Netlink attributes
5  *
6  *	This library is free software; you can redistribute it and/or
7  *	modify it under the terms of the GNU Lesser General Public
8  *	License as published by the Free Software Foundation version 2.1
9  *	of the License.
10  *
11  * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
12  */
13 
14 #ifndef __NLATTR_H
15 #define __NLATTR_H
16 
17 #include <stdint.h>
18 #include <linux/netlink.h>
19 /* avoid multiple definition of netlink features */
20 #define __LINUX_NETLINK_H
21 
22 /**
23  * Standard attribute types to specify validation policy
24  */
25 enum {
26 	NLA_UNSPEC,	/**< Unspecified type, binary data chunk */
27 	NLA_U8,		/**< 8 bit integer */
28 	NLA_U16,	/**< 16 bit integer */
29 	NLA_U32,	/**< 32 bit integer */
30 	NLA_U64,	/**< 64 bit integer */
31 	NLA_STRING,	/**< NUL terminated character string */
32 	NLA_FLAG,	/**< Flag */
33 	NLA_MSECS,	/**< Micro seconds (64bit) */
34 	NLA_NESTED,	/**< Nested attributes */
35 	__NLA_TYPE_MAX,
36 };
37 
38 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
39 
40 /**
41  * @ingroup attr
42  * Attribute validation policy.
43  *
44  * See section @core_doc{core_attr_parse,Attribute Parsing} for more details.
45  */
46 struct nla_policy {
47 	/** Type of attribute or NLA_UNSPEC */
48 	uint16_t	type;
49 
50 	/** Minimal length of payload required */
51 	uint16_t	minlen;
52 
53 	/** Maximal length of payload allowed */
54 	uint16_t	maxlen;
55 };
56 
57 /**
58  * @ingroup attr
59  * Iterate over a stream of attributes
60  * @arg pos	loop counter, set to current attribute
61  * @arg head	head of attribute stream
62  * @arg len	length of attribute stream
63  * @arg rem	initialized to len, holds bytes currently remaining in stream
64  */
65 #define nla_for_each_attr(pos, head, len, rem) \
66 	for (pos = head, rem = len; \
67 	     nla_ok(pos, rem); \
68 	     pos = nla_next(pos, &(rem)))
69 
70 int nla_dump_errormsg(struct nlmsghdr *nlh);
71 
72 #endif /* __NLATTR_H */
73