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git.proxmox.com Git - ovs.git/blob - lib/netlink.h
2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
20 /* Netlink message helpers.
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".
26 * Netlink is not suitable for use in physical networks of heterogeneous
27 * machines because host byte order is used throughout.
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.
37 #include "netlink-protocol.h"
38 #include "openvswitch/types.h"
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);
49 /* Appending and prepending headers and raw data. */
50 void nl_msg_put_nlmsghdr(struct ofpbuf
*, size_t expected_payload
,
51 uint32_t type
, uint32_t flags
);
52 void nl_msg_put_genlmsghdr(struct ofpbuf
*, size_t expected_payload
,
53 int family
, uint32_t flags
,
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 void nl_msg_push(struct ofpbuf
*, const void *, size_t);
58 void *nl_msg_push_uninit(struct ofpbuf
*, size_t);
60 /* Appending attributes. */
61 void *nl_msg_put_unspec_uninit(struct ofpbuf
*, uint16_t type
, size_t);
62 void nl_msg_put_unspec(struct ofpbuf
*, uint16_t type
, const void *, size_t);
63 void nl_msg_put_flag(struct ofpbuf
*, uint16_t type
);
64 void nl_msg_put_u8(struct ofpbuf
*, uint16_t type
, uint8_t value
);
65 void nl_msg_put_u16(struct ofpbuf
*, uint16_t type
, uint16_t value
);
66 void nl_msg_put_u32(struct ofpbuf
*, uint16_t type
, uint32_t value
);
67 void nl_msg_put_u64(struct ofpbuf
*, uint16_t type
, uint64_t value
);
68 void nl_msg_put_be16(struct ofpbuf
*, uint16_t type
, ovs_be16 value
);
69 void nl_msg_put_be32(struct ofpbuf
*, uint16_t type
, ovs_be32 value
);
70 void nl_msg_put_be64(struct ofpbuf
*, uint16_t type
, ovs_be64 value
);
71 void nl_msg_put_string(struct ofpbuf
*, uint16_t type
, const char *value
);
73 size_t nl_msg_start_nested(struct ofpbuf
*, uint16_t type
);
74 void nl_msg_end_nested(struct ofpbuf
*, size_t offset
);
75 void nl_msg_put_nested(struct ofpbuf
*, uint16_t type
,
76 const void *data
, size_t size
);
78 /* Prepending attributes. */
79 void *nl_msg_push_unspec_uninit(struct ofpbuf
*, uint16_t type
, size_t);
80 void nl_msg_push_unspec(struct ofpbuf
*, uint16_t type
, const void *, size_t);
81 void nl_msg_push_flag(struct ofpbuf
*, uint16_t type
);
82 void nl_msg_push_u8(struct ofpbuf
*, uint16_t type
, uint8_t value
);
83 void nl_msg_push_u16(struct ofpbuf
*, uint16_t type
, uint16_t value
);
84 void nl_msg_push_u32(struct ofpbuf
*, uint16_t type
, uint32_t value
);
85 void nl_msg_push_u64(struct ofpbuf
*, uint16_t type
, uint64_t value
);
86 void nl_msg_push_be16(struct ofpbuf
*, uint16_t type
, ovs_be16 value
);
87 void nl_msg_push_be32(struct ofpbuf
*, uint16_t type
, ovs_be32 value
);
88 void nl_msg_push_be64(struct ofpbuf
*, uint16_t type
, ovs_be64 value
);
89 void nl_msg_push_string(struct ofpbuf
*, uint16_t type
, const char *value
);
91 /* Separating buffers into individual messages. */
92 struct nlmsghdr
*nl_msg_next(struct ofpbuf
*buffer
, struct ofpbuf
*msg
);
94 /* Sizes of various attribute types, in bytes, including the attribute header
96 #define NL_ATTR_SIZE(PAYLOAD_SIZE) (NLA_HDRLEN + NLA_ALIGN(PAYLOAD_SIZE))
97 #define NL_A_U8_SIZE NL_ATTR_SIZE(sizeof(uint8_t))
98 #define NL_A_U16_SIZE NL_ATTR_SIZE(sizeof(uint16_t))
99 #define NL_A_U32_SIZE NL_ATTR_SIZE(sizeof(uint32_t))
100 #define NL_A_U64_SIZE NL_ATTR_SIZE(sizeof(uint64_t))
101 #define NL_A_BE16_SIZE NL_ATTR_SIZE(sizeof(ovs_be16))
102 #define NL_A_BE32_SIZE NL_ATTR_SIZE(sizeof(ovs_be32))
103 #define NL_A_BE64_SIZE NL_ATTR_SIZE(sizeof(ovs_be64))
104 #define NL_A_FLAG_SIZE NL_ATTR_SIZE(0)
106 /* Netlink attribute types. */
113 NL_A_BE16
= NL_A_U16
,
115 NL_A_BE32
= NL_A_U32
,
117 NL_A_BE64
= NL_A_U64
,
124 /* Netlink attribute iteration. */
125 static inline struct nlattr
*
126 nl_attr_next(const struct nlattr
*nla
)
128 return (void *) ((uint8_t *) nla
+ NLA_ALIGN(nla
->nla_len
));
132 nl_attr_is_valid(const struct nlattr
*nla
, size_t maxlen
)
134 return (maxlen
>= sizeof *nla
135 && nla
->nla_len
>= sizeof *nla
136 && NLA_ALIGN(nla
->nla_len
) <= maxlen
);
139 /* This macro is careful to check for attributes with bad lengths. */
140 #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \
141 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
142 nl_attr_is_valid(ITER, LEFT); \
143 (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER))
146 /* This macro does not check for attributes with bad lengths. It should only
147 * be used with messages from trusted sources or with messages that have
148 * already been validated (e.g. with NL_ATTR_FOR_EACH). */
149 #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \
150 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
152 (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER))
154 /* These variants are convenient for iterating nested attributes. */
155 #define NL_NESTED_FOR_EACH(ITER, LEFT, A) \
156 NL_ATTR_FOR_EACH(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
157 #define NL_NESTED_FOR_EACH_UNSAFE(ITER, LEFT, A) \
158 NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
160 /* Netlink attribute parsing. */
161 int nl_attr_type(const struct nlattr
*);
162 const void *nl_attr_get(const struct nlattr
*);
163 size_t nl_attr_get_size(const struct nlattr
*);
164 const void *nl_attr_get_unspec(const struct nlattr
*, size_t size
);
165 bool nl_attr_get_flag(const struct nlattr
*);
166 uint8_t nl_attr_get_u8(const struct nlattr
*);
167 uint16_t nl_attr_get_u16(const struct nlattr
*);
168 uint32_t nl_attr_get_u32(const struct nlattr
*);
169 uint64_t nl_attr_get_u64(const struct nlattr
*);
170 ovs_be16
nl_attr_get_be16(const struct nlattr
*);
171 ovs_be32
nl_attr_get_be32(const struct nlattr
*);
172 ovs_be64
nl_attr_get_be64(const struct nlattr
*);
173 const char *nl_attr_get_string(const struct nlattr
*);
174 void nl_attr_get_nested(const struct nlattr
*, struct ofpbuf
*);
176 /* Netlink attribute policy.
178 * Specifies how to parse a single attribute from a Netlink message payload.
182 enum nl_attr_type type
;
183 size_t min_len
, max_len
;
187 #define NL_POLICY_FOR(TYPE) \
188 .type = NL_A_UNSPEC, .min_len = sizeof(TYPE), .max_len = sizeof(TYPE)
190 bool nl_policy_parse(const struct ofpbuf
*, size_t offset
,
191 const struct nl_policy
[],
192 struct nlattr
*[], size_t n_attrs
);
193 bool nl_parse_nested(const struct nlattr
*, const struct nl_policy
[],
194 struct nlattr
*[], size_t n_attrs
);
196 const struct nlattr
*nl_attr_find(const struct ofpbuf
*, size_t hdr_len
,
198 const struct nlattr
*nl_attr_find_nested(const struct nlattr
*, uint16_t type
);
199 const struct nlattr
*nl_attr_find__(const struct nlattr
*attrs
, size_t size
,
202 #endif /* netlink.h */