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 <string.h> |
14 | #include <errno.h> |
15 | #include <linux/netlink.h> |
16 | #include <linux/rtnetlink.h> |
17 | #include <linux/genetlink.h> |
18 | |
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 | LIBBPF_NLA_UNSPEC, /**< Unspecified type, binary data chunk */ |
27 | LIBBPF_NLA_U8, /**< 8 bit integer */ |
28 | LIBBPF_NLA_U16, /**< 16 bit integer */ |
29 | LIBBPF_NLA_U32, /**< 32 bit integer */ |
30 | LIBBPF_NLA_U64, /**< 64 bit integer */ |
31 | LIBBPF_NLA_STRING, /**< NUL terminated character string */ |
32 | LIBBPF_NLA_FLAG, /**< Flag */ |
33 | LIBBPF_NLA_MSECS, /**< Micro seconds (64bit) */ |
34 | LIBBPF_NLA_NESTED, /**< Nested attributes */ |
35 | __LIBBPF_NLA_TYPE_MAX, |
36 | }; |
37 | |
38 | #define LIBBPF_NLA_TYPE_MAX (__LIBBPF_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 libbpf_nla_policy { |
47 | /** Type of attribute or LIBBPF_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 | struct libbpf_nla_req { |
58 | struct nlmsghdr nh; |
59 | union { |
60 | struct ifinfomsg ifinfo; |
61 | struct tcmsg tc; |
62 | struct genlmsghdr gnl; |
63 | }; |
64 | char buf[128]; |
65 | }; |
66 | |
67 | /** |
68 | * @ingroup attr |
69 | * Iterate over a stream of attributes |
70 | * @arg pos loop counter, set to current attribute |
71 | * @arg head head of attribute stream |
72 | * @arg len length of attribute stream |
73 | * @arg rem initialized to len, holds bytes currently remaining in stream |
74 | */ |
75 | #define libbpf_nla_for_each_attr(pos, head, len, rem) \ |
76 | for (pos = head, rem = len; \ |
77 | nla_ok(pos, rem); \ |
78 | pos = nla_next(pos, &(rem))) |
79 | |
80 | /** |
81 | * libbpf_nla_data - head of payload |
82 | * @nla: netlink attribute |
83 | */ |
84 | static inline void *libbpf_nla_data(const struct nlattr *nla) |
85 | { |
86 | return (void *)nla + NLA_HDRLEN; |
87 | } |
88 | |
89 | static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla) |
90 | { |
91 | return *(uint8_t *)libbpf_nla_data(nla); |
92 | } |
93 | |
94 | static inline uint16_t libbpf_nla_getattr_u16(const struct nlattr *nla) |
95 | { |
96 | return *(uint16_t *)libbpf_nla_data(nla); |
97 | } |
98 | |
99 | static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla) |
100 | { |
101 | return *(uint32_t *)libbpf_nla_data(nla); |
102 | } |
103 | |
104 | static inline uint64_t libbpf_nla_getattr_u64(const struct nlattr *nla) |
105 | { |
106 | return *(uint64_t *)libbpf_nla_data(nla); |
107 | } |
108 | |
109 | static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla) |
110 | { |
111 | return (const char *)libbpf_nla_data(nla); |
112 | } |
113 | |
114 | /** |
115 | * libbpf_nla_len - length of payload |
116 | * @nla: netlink attribute |
117 | */ |
118 | static inline int libbpf_nla_len(const struct nlattr *nla) |
119 | { |
120 | return nla->nla_len - NLA_HDRLEN; |
121 | } |
122 | |
123 | int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, |
124 | int len, struct libbpf_nla_policy *policy); |
125 | int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype, |
126 | struct nlattr *nla, |
127 | struct libbpf_nla_policy *policy); |
128 | |
129 | int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh); |
130 | |
131 | static inline struct nlattr *nla_data(struct nlattr *nla) |
132 | { |
133 | return (struct nlattr *)((void *)nla + NLA_HDRLEN); |
134 | } |
135 | |
136 | static inline struct nlattr *req_tail(struct libbpf_nla_req *req) |
137 | { |
138 | return (struct nlattr *)((void *)req + NLMSG_ALIGN(req->nh.nlmsg_len)); |
139 | } |
140 | |
141 | static inline int nlattr_add(struct libbpf_nla_req *req, int type, |
142 | const void *data, int len) |
143 | { |
144 | struct nlattr *nla; |
145 | |
146 | if (NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(NLA_HDRLEN + len) > sizeof(*req)) |
147 | return -EMSGSIZE; |
148 | if (!!data != !!len) |
149 | return -EINVAL; |
150 | |
151 | nla = req_tail(req); |
152 | nla->nla_type = type; |
153 | nla->nla_len = NLA_HDRLEN + len; |
154 | if (data) |
155 | memcpy(nla_data(nla), data, len); |
156 | req->nh.nlmsg_len = NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(nla->nla_len); |
157 | return 0; |
158 | } |
159 | |
160 | static inline struct nlattr *nlattr_begin_nested(struct libbpf_nla_req *req, int type) |
161 | { |
162 | struct nlattr *tail; |
163 | |
164 | tail = req_tail(req); |
165 | if (nlattr_add(req, type: type | NLA_F_NESTED, NULL, len: 0)) |
166 | return NULL; |
167 | return tail; |
168 | } |
169 | |
170 | static inline void nlattr_end_nested(struct libbpf_nla_req *req, |
171 | struct nlattr *tail) |
172 | { |
173 | tail->nla_len = (void *)req_tail(req) - (void *)tail; |
174 | } |
175 | |
176 | #endif /* __LIBBPF_NLATTR_H */ |
177 | |