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064af421 | 1 | /* |
b18fcf8e | 2 | * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks. |
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 | ||
49 | /* Appending 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); | |
57 | ||
58 | /* Appending attributes. */ | |
59 | void *nl_msg_put_unspec_uninit(struct ofpbuf *, uint16_t type, size_t); | |
60 | void nl_msg_put_unspec(struct ofpbuf *, uint16_t type, const void *, size_t); | |
61 | void nl_msg_put_flag(struct ofpbuf *, uint16_t type); | |
62 | void nl_msg_put_u8(struct ofpbuf *, uint16_t type, uint8_t value); | |
63 | void nl_msg_put_u16(struct ofpbuf *, uint16_t type, uint16_t value); | |
64 | void nl_msg_put_u32(struct ofpbuf *, uint16_t type, uint32_t value); | |
65 | void nl_msg_put_u64(struct ofpbuf *, uint16_t type, uint64_t value); | |
ee913f98 BP |
66 | void nl_msg_put_be16(struct ofpbuf *, uint16_t type, ovs_be16 value); |
67 | void nl_msg_put_be32(struct ofpbuf *, uint16_t type, ovs_be32 value); | |
68 | void nl_msg_put_be64(struct ofpbuf *, uint16_t type, ovs_be64 value); | |
064af421 | 69 | void nl_msg_put_string(struct ofpbuf *, uint16_t type, const char *value); |
38a99756 BP |
70 | |
71 | size_t nl_msg_start_nested(struct ofpbuf *, uint16_t type); | |
72 | void nl_msg_end_nested(struct ofpbuf *, size_t offset); | |
73 | void nl_msg_put_nested(struct ofpbuf *, uint16_t type, | |
74 | const void *data, size_t size); | |
974d6a6d BP |
75 | |
76 | /* Separating buffers into individual messages. */ | |
77 | struct nlmsghdr *nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg); | |
064af421 BP |
78 | \f |
79 | /* Netlink attribute types. */ | |
80 | enum nl_attr_type | |
81 | { | |
82 | NL_A_NO_ATTR = 0, | |
83 | NL_A_UNSPEC, | |
84 | NL_A_U8, | |
85 | NL_A_U16, | |
18c58479 | 86 | NL_A_BE16 = NL_A_U16, |
064af421 | 87 | NL_A_U32, |
18c58479 | 88 | NL_A_BE32 = NL_A_U32, |
064af421 | 89 | NL_A_U64, |
18c58479 | 90 | NL_A_BE64 = NL_A_U64, |
064af421 BP |
91 | NL_A_STRING, |
92 | NL_A_FLAG, | |
93 | NL_A_NESTED, | |
94 | N_NL_ATTR_TYPES | |
95 | }; | |
96 | ||
7f8ca645 BP |
97 | /* Netlink attribute iteration. */ |
98 | static inline struct nlattr * | |
99 | nl_attr_next(const struct nlattr *nla) | |
100 | { | |
101 | return (struct nlattr *) ((uint8_t *) nla + NLA_ALIGN(nla->nla_len)); | |
102 | } | |
103 | ||
104 | static inline bool | |
105 | nl_attr_is_valid(const struct nlattr *nla, size_t maxlen) | |
106 | { | |
107 | return (maxlen >= sizeof *nla | |
108 | && nla->nla_len >= sizeof *nla | |
109 | && NLA_ALIGN(nla->nla_len) <= maxlen); | |
110 | } | |
111 | ||
112 | /* This macro is careful to check for attributes with bad lengths. */ | |
113 | #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \ | |
114 | for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ | |
115 | nl_attr_is_valid(ITER, LEFT); \ | |
116 | (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER)) | |
117 | ||
118 | ||
119 | /* This macro does not check for attributes with bad lengths. It should only | |
120 | * be used with messages from trusted sources or with messages that have | |
b18fcf8e | 121 | * already been validated (e.g. with NL_ATTR_FOR_EACH). */ |
7f8ca645 BP |
122 | #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \ |
123 | for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ | |
124 | (LEFT) > 0; \ | |
125 | (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER)) | |
126 | ||
064af421 | 127 | /* Netlink attribute parsing. */ |
7c624478 | 128 | int nl_attr_type(const struct nlattr *); |
064af421 BP |
129 | const void *nl_attr_get(const struct nlattr *); |
130 | size_t nl_attr_get_size(const struct nlattr *); | |
131 | const void *nl_attr_get_unspec(const struct nlattr *, size_t size); | |
132 | bool nl_attr_get_flag(const struct nlattr *); | |
133 | uint8_t nl_attr_get_u8(const struct nlattr *); | |
134 | uint16_t nl_attr_get_u16(const struct nlattr *); | |
135 | uint32_t nl_attr_get_u32(const struct nlattr *); | |
136 | uint64_t nl_attr_get_u64(const struct nlattr *); | |
ee913f98 BP |
137 | ovs_be16 nl_attr_get_be16(const struct nlattr *); |
138 | ovs_be32 nl_attr_get_be32(const struct nlattr *); | |
139 | ovs_be64 nl_attr_get_be64(const struct nlattr *); | |
064af421 | 140 | const char *nl_attr_get_string(const struct nlattr *); |
25eeae6a | 141 | void nl_attr_get_nested(const struct nlattr *, struct ofpbuf *); |
064af421 BP |
142 | |
143 | /* Netlink attribute policy. | |
144 | * | |
145 | * Specifies how to parse a single attribute from a Netlink message payload. | |
146 | */ | |
147 | struct nl_policy | |
148 | { | |
149 | enum nl_attr_type type; | |
150 | size_t min_len, max_len; | |
151 | bool optional; | |
152 | }; | |
153 | ||
154 | bool nl_policy_parse(const struct ofpbuf *, size_t offset, | |
155 | const struct nl_policy[], | |
156 | struct nlattr *[], size_t n_attrs); | |
25eeae6a BP |
157 | bool nl_parse_nested(const struct nlattr *, const struct nl_policy[], |
158 | struct nlattr *[], size_t n_attrs); | |
064af421 | 159 | |
b18fcf8e BP |
160 | const struct nlattr *nl_attr_find(const struct ofpbuf *, size_t hdr_len, |
161 | uint16_t type); | |
162 | const struct nlattr *nl_attr_find_nested(const struct nlattr *, uint16_t type); | |
163 | ||
064af421 | 164 | #endif /* netlink.h */ |