1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2
  3/*
  4 * NETLINK      Netlink attributes
  5 *
  6 * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
  7 */
  8
  9#ifndef __LIBBPF_NLATTR_H
 10#define __LIBBPF_NLATTR_H
 11
 12#include <stdint.h>
 13#include <linux/netlink.h>
 14/* avoid multiple definition of netlink features */
 15#define __LINUX_NETLINK_H
 16
 17/**
 18 * Standard attribute types to specify validation policy
 19 */
 20enum {
 21	LIBBPF_NLA_UNSPEC,	/**< Unspecified type, binary data chunk */
 22	LIBBPF_NLA_U8,		/**< 8 bit integer */
 23	LIBBPF_NLA_U16,		/**< 16 bit integer */
 24	LIBBPF_NLA_U32,		/**< 32 bit integer */
 25	LIBBPF_NLA_U64,		/**< 64 bit integer */
 26	LIBBPF_NLA_STRING,	/**< NUL terminated character string */
 27	LIBBPF_NLA_FLAG,	/**< Flag */
 28	LIBBPF_NLA_MSECS,	/**< Micro seconds (64bit) */
 29	LIBBPF_NLA_NESTED,	/**< Nested attributes */
 30	__LIBBPF_NLA_TYPE_MAX,
 31};
 32
 33#define LIBBPF_NLA_TYPE_MAX (__LIBBPF_NLA_TYPE_MAX - 1)
 34
 35/**
 36 * @ingroup attr
 37 * Attribute validation policy.
 38 *
 39 * See section @core_doc{core_attr_parse,Attribute Parsing} for more details.
 40 */
 41struct libbpf_nla_policy {
 42	/** Type of attribute or LIBBPF_NLA_UNSPEC */
 43	uint16_t	type;
 44
 45	/** Minimal length of payload required */
 46	uint16_t	minlen;
 47
 48	/** Maximal length of payload allowed */
 49	uint16_t	maxlen;
 50};
 51
 52/**
 53 * @ingroup attr
 54 * Iterate over a stream of attributes
 55 * @arg pos	loop counter, set to current attribute
 56 * @arg head	head of attribute stream
 57 * @arg len	length of attribute stream
 58 * @arg rem	initialized to len, holds bytes currently remaining in stream
 59 */
 60#define libbpf_nla_for_each_attr(pos, head, len, rem) \
 61	for (pos = head, rem = len; \
 62	     nla_ok(pos, rem); \
 63	     pos = nla_next(pos, &(rem)))
 64
 65/**
 66 * libbpf_nla_data - head of payload
 67 * @nla: netlink attribute
 68 */
 69static inline void *libbpf_nla_data(const struct nlattr *nla)
 70{
 71	return (char *) nla + NLA_HDRLEN;
 72}
 73
 74static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)
 75{
 76	return *(uint8_t *)libbpf_nla_data(nla);
 77}
 78
 79static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)
 80{
 81	return *(uint32_t *)libbpf_nla_data(nla);
 82}
 83
 84static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla)
 85{
 86	return (const char *)libbpf_nla_data(nla);
 87}
 88
 89/**
 90 * libbpf_nla_len - length of payload
 91 * @nla: netlink attribute
 92 */
 93static inline int libbpf_nla_len(const struct nlattr *nla)
 94{
 95	return nla->nla_len - NLA_HDRLEN;
 96}
 97
 98int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
 99		     int len, struct libbpf_nla_policy *policy);
100int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,
101			    struct nlattr *nla,
102			    struct libbpf_nla_policy *policy);
103
104int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh);
105
106#endif /* __LIBBPF_NLATTR_H */