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064af421 | 1 | /* |
91496302 | 2 | * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc. |
064af421 | 3 | * |
a14bc59f BP |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
064af421 | 7 | * |
a14bc59f BP |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
064af421 BP |
15 | */ |
16 | ||
17 | #ifndef NETLINK_H | |
18 | #define NETLINK_H 1 | |
19 | ||
2fe27d5a | 20 | /* Netlink message helpers. |
064af421 BP |
21 | * |
22 | * Netlink is a datagram-based network protocol primarily for communication | |
23 | * between user processes and the kernel, and mainly on Linux. Netlink is | |
24 | * specified in RFC 3549, "Linux Netlink as an IP Services Protocol". | |
25 | * | |
26 | * Netlink is not suitable for use in physical networks of heterogeneous | |
2fe27d5a BP |
27 | * machines because host byte order is used throughout. |
28 | * | |
29 | * This header file defines helper functions for working with Netlink messages. | |
30 | * For Netlink protocol definitions, see netlink-protocol.h. For | |
31 | * Linux-specific definitions for Netlink sockets, see netlink-socket.h. | |
32 | */ | |
064af421 BP |
33 | |
34 | #include <stdbool.h> | |
2fe27d5a | 35 | #include <stddef.h> |
064af421 | 36 | #include <stdint.h> |
7f8ca645 BP |
37 | #include "netlink-protocol.h" |
38 | #include "openvswitch/types.h" | |
064af421 BP |
39 | |
40 | struct ofpbuf; | |
064af421 BP |
41 | struct nlattr; |
42 | ||
064af421 BP |
43 | /* Accessing headers and data. */ |
44 | struct nlmsghdr *nl_msg_nlmsghdr(const struct ofpbuf *); | |
45 | struct genlmsghdr *nl_msg_genlmsghdr(const struct ofpbuf *); | |
46 | bool nl_msg_nlmsgerr(const struct ofpbuf *, int *error); | |
47 | void nl_msg_reserve(struct ofpbuf *, size_t); | |
48 | ||
46d34fef | 49 | /* Appending and prepending headers and raw data. */ |
69123704 | 50 | void nl_msg_put_nlmsghdr(struct ofpbuf *, size_t expected_payload, |
064af421 | 51 | uint32_t type, uint32_t flags); |
69123704 BP |
52 | void nl_msg_put_genlmsghdr(struct ofpbuf *, size_t expected_payload, |
53 | int family, uint32_t flags, | |
064af421 BP |
54 | uint8_t cmd, uint8_t version); |
55 | void nl_msg_put(struct ofpbuf *, const void *, size_t); | |
56 | void *nl_msg_put_uninit(struct ofpbuf *, size_t); | |
46d34fef BP |
57 | void nl_msg_push(struct ofpbuf *, const void *, size_t); |
58 | void *nl_msg_push_uninit(struct ofpbuf *, size_t); | |
064af421 BP |
59 | |
60 | /* Appending attributes. */ | |
61 | void *nl_msg_put_unspec_uninit(struct ofpbuf *, uint16_t type, size_t); | |
9ddf12cc | 62 | void *nl_msg_put_unspec_zero(struct ofpbuf *, uint16_t type, size_t); |
064af421 BP |
63 | void nl_msg_put_unspec(struct ofpbuf *, uint16_t type, const void *, size_t); |
64 | void nl_msg_put_flag(struct ofpbuf *, uint16_t type); | |
65 | void nl_msg_put_u8(struct ofpbuf *, uint16_t type, uint8_t value); | |
66 | void nl_msg_put_u16(struct ofpbuf *, uint16_t type, uint16_t value); | |
67 | void nl_msg_put_u32(struct ofpbuf *, uint16_t type, uint32_t value); | |
68 | void nl_msg_put_u64(struct ofpbuf *, uint16_t type, uint64_t value); | |
ee913f98 BP |
69 | void nl_msg_put_be16(struct ofpbuf *, uint16_t type, ovs_be16 value); |
70 | void nl_msg_put_be32(struct ofpbuf *, uint16_t type, ovs_be32 value); | |
71 | void nl_msg_put_be64(struct ofpbuf *, uint16_t type, ovs_be64 value); | |
4e022ec0 | 72 | void nl_msg_put_odp_port(struct ofpbuf *, uint16_t type, odp_port_t value); |
064af421 | 73 | void nl_msg_put_string(struct ofpbuf *, uint16_t type, const char *value); |
38a99756 BP |
74 | |
75 | size_t nl_msg_start_nested(struct ofpbuf *, uint16_t type); | |
76 | void nl_msg_end_nested(struct ofpbuf *, size_t offset); | |
77 | void nl_msg_put_nested(struct ofpbuf *, uint16_t type, | |
78 | const void *data, size_t size); | |
974d6a6d | 79 | |
46d34fef BP |
80 | /* Prepending attributes. */ |
81 | void *nl_msg_push_unspec_uninit(struct ofpbuf *, uint16_t type, size_t); | |
82 | void nl_msg_push_unspec(struct ofpbuf *, uint16_t type, const void *, size_t); | |
83 | void nl_msg_push_flag(struct ofpbuf *, uint16_t type); | |
84 | void nl_msg_push_u8(struct ofpbuf *, uint16_t type, uint8_t value); | |
85 | void nl_msg_push_u16(struct ofpbuf *, uint16_t type, uint16_t value); | |
86 | void nl_msg_push_u32(struct ofpbuf *, uint16_t type, uint32_t value); | |
87 | void nl_msg_push_u64(struct ofpbuf *, uint16_t type, uint64_t value); | |
88 | void nl_msg_push_be16(struct ofpbuf *, uint16_t type, ovs_be16 value); | |
89 | void nl_msg_push_be32(struct ofpbuf *, uint16_t type, ovs_be32 value); | |
90 | void nl_msg_push_be64(struct ofpbuf *, uint16_t type, ovs_be64 value); | |
91 | void nl_msg_push_string(struct ofpbuf *, uint16_t type, const char *value); | |
92 | ||
974d6a6d BP |
93 | /* Separating buffers into individual messages. */ |
94 | struct nlmsghdr *nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg); | |
3a706b33 BP |
95 | |
96 | /* Sizes of various attribute types, in bytes, including the attribute header | |
91496302 BP |
97 | * and padding. |
98 | * | |
99 | * A minimum-size attribute is 4 bytes long: 4 bytes of header, no bytes of | |
100 | * payload, no padding. | |
101 | * | |
102 | * A maximum-size attribute is 65536 bytes long: 4 bytes of header, 65531 bytes | |
103 | * of payload, 1 byte of padding. (Thus, NL_ATTR_SIZE() of a maximum length | |
104 | * attribute payload does not fit in 16 bits.) */ | |
3a706b33 BP |
105 | #define NL_ATTR_SIZE(PAYLOAD_SIZE) (NLA_HDRLEN + NLA_ALIGN(PAYLOAD_SIZE)) |
106 | #define NL_A_U8_SIZE NL_ATTR_SIZE(sizeof(uint8_t)) | |
107 | #define NL_A_U16_SIZE NL_ATTR_SIZE(sizeof(uint16_t)) | |
108 | #define NL_A_U32_SIZE NL_ATTR_SIZE(sizeof(uint32_t)) | |
109 | #define NL_A_U64_SIZE NL_ATTR_SIZE(sizeof(uint64_t)) | |
110 | #define NL_A_BE16_SIZE NL_ATTR_SIZE(sizeof(ovs_be16)) | |
111 | #define NL_A_BE32_SIZE NL_ATTR_SIZE(sizeof(ovs_be32)) | |
112 | #define NL_A_BE64_SIZE NL_ATTR_SIZE(sizeof(ovs_be64)) | |
113 | #define NL_A_FLAG_SIZE NL_ATTR_SIZE(0) | |
542024c4 BP |
114 | |
115 | bool nl_attr_oversized(size_t payload_size); | |
064af421 BP |
116 | \f |
117 | /* Netlink attribute types. */ | |
118 | enum nl_attr_type | |
119 | { | |
120 | NL_A_NO_ATTR = 0, | |
121 | NL_A_UNSPEC, | |
122 | NL_A_U8, | |
123 | NL_A_U16, | |
18c58479 | 124 | NL_A_BE16 = NL_A_U16, |
064af421 | 125 | NL_A_U32, |
18c58479 | 126 | NL_A_BE32 = NL_A_U32, |
064af421 | 127 | NL_A_U64, |
18c58479 | 128 | NL_A_BE64 = NL_A_U64, |
064af421 BP |
129 | NL_A_STRING, |
130 | NL_A_FLAG, | |
131 | NL_A_NESTED, | |
132 | N_NL_ATTR_TYPES | |
133 | }; | |
134 | ||
7f8ca645 BP |
135 | /* Netlink attribute iteration. */ |
136 | static inline struct nlattr * | |
137 | nl_attr_next(const struct nlattr *nla) | |
138 | { | |
08c4a39e | 139 | return (void *) ((uint8_t *) nla + NLA_ALIGN(nla->nla_len)); |
7f8ca645 BP |
140 | } |
141 | ||
142 | static inline bool | |
143 | nl_attr_is_valid(const struct nlattr *nla, size_t maxlen) | |
144 | { | |
145 | return (maxlen >= sizeof *nla | |
146 | && nla->nla_len >= sizeof *nla | |
b66b7b18 TG |
147 | && nla->nla_len <= maxlen); |
148 | } | |
149 | ||
150 | static inline size_t | |
151 | nl_attr_len_pad(const struct nlattr *nla, size_t maxlen) | |
152 | { | |
153 | size_t len = NLA_ALIGN(nla->nla_len); | |
154 | ||
155 | return len <= maxlen ? len : nla->nla_len; | |
7f8ca645 BP |
156 | } |
157 | ||
158 | /* This macro is careful to check for attributes with bad lengths. */ | |
159 | #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \ | |
160 | for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ | |
161 | nl_attr_is_valid(ITER, LEFT); \ | |
b66b7b18 | 162 | (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER)) |
7f8ca645 BP |
163 | |
164 | ||
165 | /* This macro does not check for attributes with bad lengths. It should only | |
166 | * be used with messages from trusted sources or with messages that have | |
b18fcf8e | 167 | * already been validated (e.g. with NL_ATTR_FOR_EACH). */ |
7f8ca645 BP |
168 | #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \ |
169 | for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ | |
170 | (LEFT) > 0; \ | |
b66b7b18 | 171 | (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER)) |
7f8ca645 | 172 | |
6d23c6f4 BP |
173 | /* These variants are convenient for iterating nested attributes. */ |
174 | #define NL_NESTED_FOR_EACH(ITER, LEFT, A) \ | |
175 | NL_ATTR_FOR_EACH(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A)) | |
176 | #define NL_NESTED_FOR_EACH_UNSAFE(ITER, LEFT, A) \ | |
177 | NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A)) | |
178 | ||
064af421 | 179 | /* Netlink attribute parsing. */ |
7c624478 | 180 | int nl_attr_type(const struct nlattr *); |
064af421 BP |
181 | const void *nl_attr_get(const struct nlattr *); |
182 | size_t nl_attr_get_size(const struct nlattr *); | |
183 | const void *nl_attr_get_unspec(const struct nlattr *, size_t size); | |
184 | bool nl_attr_get_flag(const struct nlattr *); | |
185 | uint8_t nl_attr_get_u8(const struct nlattr *); | |
186 | uint16_t nl_attr_get_u16(const struct nlattr *); | |
187 | uint32_t nl_attr_get_u32(const struct nlattr *); | |
188 | uint64_t nl_attr_get_u64(const struct nlattr *); | |
ee913f98 BP |
189 | ovs_be16 nl_attr_get_be16(const struct nlattr *); |
190 | ovs_be32 nl_attr_get_be32(const struct nlattr *); | |
191 | ovs_be64 nl_attr_get_be64(const struct nlattr *); | |
4e022ec0 | 192 | odp_port_t nl_attr_get_odp_port(const struct nlattr *); |
064af421 | 193 | const char *nl_attr_get_string(const struct nlattr *); |
25eeae6a | 194 | void nl_attr_get_nested(const struct nlattr *, struct ofpbuf *); |
064af421 BP |
195 | |
196 | /* Netlink attribute policy. | |
197 | * | |
198 | * Specifies how to parse a single attribute from a Netlink message payload. | |
199 | */ | |
200 | struct nl_policy | |
201 | { | |
202 | enum nl_attr_type type; | |
203 | size_t min_len, max_len; | |
204 | bool optional; | |
205 | }; | |
206 | ||
f7df9823 BP |
207 | #define NL_POLICY_FOR(TYPE) \ |
208 | .type = NL_A_UNSPEC, .min_len = sizeof(TYPE), .max_len = sizeof(TYPE) | |
209 | ||
be3330a6 BP |
210 | bool nl_attr_validate(const struct nlattr *, const struct nl_policy *); |
211 | ||
064af421 BP |
212 | bool nl_policy_parse(const struct ofpbuf *, size_t offset, |
213 | const struct nl_policy[], | |
214 | struct nlattr *[], size_t n_attrs); | |
25eeae6a BP |
215 | bool nl_parse_nested(const struct nlattr *, const struct nl_policy[], |
216 | struct nlattr *[], size_t n_attrs); | |
064af421 | 217 | |
b18fcf8e BP |
218 | const struct nlattr *nl_attr_find(const struct ofpbuf *, size_t hdr_len, |
219 | uint16_t type); | |
220 | const struct nlattr *nl_attr_find_nested(const struct nlattr *, uint16_t type); | |
0b6c119b JG |
221 | const struct nlattr *nl_attr_find__(const struct nlattr *attrs, size_t size, |
222 | uint16_t type); | |
b18fcf8e | 223 | |
064af421 | 224 | #endif /* netlink.h */ |