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 */
20 enum {
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 */
41 struct 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 */
libbpf_nla_data(const struct nlattr * nla)69 static inline void *libbpf_nla_data(const struct nlattr *nla)
70 {
71 return (char *) nla + NLA_HDRLEN;
72 }
73
libbpf_nla_getattr_u8(const struct nlattr * nla)74 static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)
75 {
76 return *(uint8_t *)libbpf_nla_data(nla);
77 }
78
libbpf_nla_getattr_u32(const struct nlattr * nla)79 static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)
80 {
81 return *(uint32_t *)libbpf_nla_data(nla);
82 }
83
libbpf_nla_getattr_str(const struct nlattr * nla)84 static 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 */
libbpf_nla_len(const struct nlattr * nla)93 static inline int libbpf_nla_len(const struct nlattr *nla)
94 {
95 return nla->nla_len - NLA_HDRLEN;
96 }
97
98 int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
99 int len, struct libbpf_nla_policy *policy);
100 int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,
101 struct nlattr *nla,
102 struct libbpf_nla_policy *policy);
103
104 int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh);
105
106 #endif /* __LIBBPF_NLATTR_H */
107