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1 : : /*
2 : : * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc.
3 : : *
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:
7 : : *
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.
15 : : */
16 : :
17 : : #ifndef NETLINK_H
18 : : #define NETLINK_H 1
19 : :
20 : : /* Netlink message helpers.
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
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 : : */
33 : :
34 : : #include <netinet/in.h>
35 : : #include <stdbool.h>
36 : : #include <stddef.h>
37 : : #include <stdint.h>
38 : : #include "netlink-protocol.h"
39 : : #include "openvswitch/types.h"
40 : :
41 : : struct ofpbuf;
42 : : struct nlattr;
43 : :
44 : : /* Accessing headers and data. */
45 : : struct nlmsghdr *nl_msg_nlmsghdr(const struct ofpbuf *);
46 : : struct genlmsghdr *nl_msg_genlmsghdr(const struct ofpbuf *);
47 : : bool nl_msg_nlmsgerr(const struct ofpbuf *, int *error);
48 : : void nl_msg_reserve(struct ofpbuf *, size_t);
49 : :
50 : : /* Appending and prepending headers and raw data. */
51 : : void nl_msg_put_nlmsghdr(struct ofpbuf *, size_t expected_payload,
52 : : uint32_t type, uint32_t flags);
53 : : void nl_msg_put_genlmsghdr(struct ofpbuf *, size_t expected_payload,
54 : : int family, uint32_t flags,
55 : : uint8_t cmd, uint8_t version);
56 : : void nl_msg_put(struct ofpbuf *, const void *, size_t);
57 : : void *nl_msg_put_uninit(struct ofpbuf *, size_t);
58 : : void nl_msg_push(struct ofpbuf *, const void *, size_t);
59 : : void *nl_msg_push_uninit(struct ofpbuf *, size_t);
60 : :
61 : : /* Appending attributes. */
62 : : void *nl_msg_put_unspec_uninit(struct ofpbuf *, uint16_t type, size_t);
63 : : void *nl_msg_put_unspec_zero(struct ofpbuf *, uint16_t type, size_t);
64 : : void nl_msg_put_unspec(struct ofpbuf *, uint16_t type, const void *, size_t);
65 : : void nl_msg_put_flag(struct ofpbuf *, uint16_t type);
66 : : void nl_msg_put_u8(struct ofpbuf *, uint16_t type, uint8_t value);
67 : : void nl_msg_put_u16(struct ofpbuf *, uint16_t type, uint16_t value);
68 : : void nl_msg_put_u32(struct ofpbuf *, uint16_t type, uint32_t value);
69 : : void nl_msg_put_u64(struct ofpbuf *, uint16_t type, uint64_t value);
70 : : void nl_msg_put_be16(struct ofpbuf *, uint16_t type, ovs_be16 value);
71 : : void nl_msg_put_be32(struct ofpbuf *, uint16_t type, ovs_be32 value);
72 : : void nl_msg_put_be64(struct ofpbuf *, uint16_t type, ovs_be64 value);
73 : : void nl_msg_put_in6_addr(struct ofpbuf *msg, uint16_t type,
74 : : const struct in6_addr *value);
75 : : void nl_msg_put_odp_port(struct ofpbuf *, uint16_t type, odp_port_t value);
76 : : void nl_msg_put_string__(struct ofpbuf *, uint16_t type, const char *value,
77 : : size_t len);
78 : : void nl_msg_put_string(struct ofpbuf *, uint16_t type, const char *value);
79 : :
80 : : size_t nl_msg_start_nested(struct ofpbuf *, uint16_t type);
81 : : void nl_msg_end_nested(struct ofpbuf *, size_t offset);
82 : : void nl_msg_put_nested(struct ofpbuf *, uint16_t type,
83 : : const void *data, size_t size);
84 : :
85 : : /* Prepending attributes. */
86 : : void *nl_msg_push_unspec_uninit(struct ofpbuf *, uint16_t type, size_t);
87 : : void nl_msg_push_unspec(struct ofpbuf *, uint16_t type, const void *, size_t);
88 : : void nl_msg_push_flag(struct ofpbuf *, uint16_t type);
89 : : void nl_msg_push_u8(struct ofpbuf *, uint16_t type, uint8_t value);
90 : : void nl_msg_push_u16(struct ofpbuf *, uint16_t type, uint16_t value);
91 : : void nl_msg_push_u32(struct ofpbuf *, uint16_t type, uint32_t value);
92 : : void nl_msg_push_u64(struct ofpbuf *, uint16_t type, uint64_t value);
93 : : void nl_msg_push_be16(struct ofpbuf *, uint16_t type, ovs_be16 value);
94 : : void nl_msg_push_be32(struct ofpbuf *, uint16_t type, ovs_be32 value);
95 : : void nl_msg_push_be64(struct ofpbuf *, uint16_t type, ovs_be64 value);
96 : : void nl_msg_push_string(struct ofpbuf *, uint16_t type, const char *value);
97 : :
98 : : /* Separating buffers into individual messages. */
99 : : struct nlmsghdr *nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg);
100 : :
101 : : /* Sizes of various attribute types, in bytes, including the attribute header
102 : : * and padding.
103 : : *
104 : : * A minimum-size attribute is 4 bytes long: 4 bytes of header, no bytes of
105 : : * payload, no padding.
106 : : *
107 : : * A maximum-size attribute is 65536 bytes long: 4 bytes of header, 65531 bytes
108 : : * of payload, 1 byte of padding. (Thus, NL_ATTR_SIZE() of a maximum length
109 : : * attribute payload does not fit in 16 bits.) */
110 : : #define NL_ATTR_SIZE(PAYLOAD_SIZE) (NLA_HDRLEN + NLA_ALIGN(PAYLOAD_SIZE))
111 : : #define NL_A_U8_SIZE NL_ATTR_SIZE(sizeof(uint8_t))
112 : : #define NL_A_U16_SIZE NL_ATTR_SIZE(sizeof(uint16_t))
113 : : #define NL_A_U32_SIZE NL_ATTR_SIZE(sizeof(uint32_t))
114 : : #define NL_A_U64_SIZE NL_ATTR_SIZE(sizeof(uint64_t))
115 : : #define NL_A_BE16_SIZE NL_ATTR_SIZE(sizeof(ovs_be16))
116 : : #define NL_A_BE32_SIZE NL_ATTR_SIZE(sizeof(ovs_be32))
117 : : #define NL_A_BE64_SIZE NL_ATTR_SIZE(sizeof(ovs_be64))
118 : : #define NL_A_FLAG_SIZE NL_ATTR_SIZE(0)
119 : : #define NL_A_IPV6_SIZE NL_ATTR_SIZE(sizeof(struct in6_addr))
120 : :
121 : : bool nl_attr_oversized(size_t payload_size);
122 : :
123 : : /* Netlink attribute types. */
124 : : enum nl_attr_type
125 : : {
126 : : NL_A_NO_ATTR = 0,
127 : : NL_A_UNSPEC,
128 : : NL_A_U8,
129 : : NL_A_U16,
130 : : NL_A_BE16 = NL_A_U16,
131 : : NL_A_U32,
132 : : NL_A_BE32 = NL_A_U32,
133 : : NL_A_U64,
134 : : NL_A_BE64 = NL_A_U64,
135 : : NL_A_STRING,
136 : : NL_A_FLAG,
137 : : NL_A_IPV6,
138 : : NL_A_NESTED,
139 : : N_NL_ATTR_TYPES
140 : : };
141 : :
142 : : /* Netlink attribute iteration. */
143 : : static inline struct nlattr *
144 : 18647290 : nl_attr_next(const struct nlattr *nla)
145 : : {
146 : 18647290 : return (void *) ((uint8_t *) nla + NLA_ALIGN(nla->nla_len));
147 : : }
148 : :
149 : : static inline bool
150 : 19030212 : nl_attr_is_valid(const struct nlattr *nla, size_t maxlen)
151 : : {
152 : 19030212 : return (maxlen >= sizeof *nla
153 [ + - ]: 18676526 : && nla->nla_len >= sizeof *nla
154 [ + + ][ + + ]: 37706738 : && nla->nla_len <= maxlen);
155 : : }
156 : :
157 : : static inline size_t
158 : 18647291 : nl_attr_len_pad(const struct nlattr *nla, size_t maxlen)
159 : : {
160 : 18647291 : size_t len = NLA_ALIGN(nla->nla_len);
161 : :
162 [ + + ]: 18647291 : return len <= maxlen ? len : nla->nla_len;
163 : : }
164 : :
165 : : /* This macro is careful to check for attributes with bad lengths. */
166 : : #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \
167 : : for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
168 : : nl_attr_is_valid(ITER, LEFT); \
169 : : (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER))
170 : :
171 : :
172 : : /* This macro does not check for attributes with bad lengths. It should only
173 : : * be used with messages from trusted sources or with messages that have
174 : : * already been validated (e.g. with NL_ATTR_FOR_EACH). */
175 : : #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \
176 : : for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
177 : : (LEFT) > 0; \
178 : : (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER))
179 : :
180 : : /* These variants are convenient for iterating nested attributes. */
181 : : #define NL_NESTED_FOR_EACH(ITER, LEFT, A) \
182 : : NL_ATTR_FOR_EACH(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
183 : : #define NL_NESTED_FOR_EACH_UNSAFE(ITER, LEFT, A) \
184 : : NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
185 : :
186 : : /* Netlink attribute parsing. */
187 : : int nl_attr_type(const struct nlattr *);
188 : : const void *nl_attr_get(const struct nlattr *);
189 : : size_t nl_attr_get_size(const struct nlattr *);
190 : : const void *nl_attr_get_unspec(const struct nlattr *, size_t size);
191 : : bool nl_attr_get_flag(const struct nlattr *);
192 : : uint8_t nl_attr_get_u8(const struct nlattr *);
193 : : uint16_t nl_attr_get_u16(const struct nlattr *);
194 : : uint32_t nl_attr_get_u32(const struct nlattr *);
195 : : uint64_t nl_attr_get_u64(const struct nlattr *);
196 : : ovs_be16 nl_attr_get_be16(const struct nlattr *);
197 : : ovs_be32 nl_attr_get_be32(const struct nlattr *);
198 : : ovs_be64 nl_attr_get_be64(const struct nlattr *);
199 : : struct in6_addr nl_attr_get_in6_addr(const struct nlattr *nla);
200 : : odp_port_t nl_attr_get_odp_port(const struct nlattr *);
201 : : const char *nl_attr_get_string(const struct nlattr *);
202 : : void nl_attr_get_nested(const struct nlattr *, struct ofpbuf *);
203 : :
204 : : /* Netlink attribute policy.
205 : : *
206 : : * Specifies how to parse a single attribute from a Netlink message payload.
207 : : */
208 : : struct nl_policy
209 : : {
210 : : enum nl_attr_type type;
211 : : size_t min_len, max_len;
212 : : bool optional;
213 : : };
214 : :
215 : : #define NL_POLICY_FOR(TYPE) \
216 : : .type = NL_A_UNSPEC, .min_len = sizeof(TYPE), .max_len = sizeof(TYPE)
217 : :
218 : : bool nl_attr_validate(const struct nlattr *, const struct nl_policy *);
219 : :
220 : : bool nl_policy_parse(const struct ofpbuf *, size_t offset,
221 : : const struct nl_policy[],
222 : : struct nlattr *[], size_t n_attrs);
223 : : bool nl_parse_nested(const struct nlattr *, const struct nl_policy[],
224 : : struct nlattr *[], size_t n_attrs);
225 : :
226 : : const struct nlattr *nl_attr_find(const struct ofpbuf *, size_t hdr_len,
227 : : uint16_t type);
228 : : const struct nlattr *nl_attr_find_nested(const struct nlattr *, uint16_t type);
229 : : const struct nlattr *nl_attr_find__(const struct nlattr *attrs, size_t size,
230 : : uint16_t type);
231 : :
232 : : #endif /* netlink.h */
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