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git.proxmox.com Git - ovs.git/blob - lib/netlink.h
2 * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc.
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.
34 #include <netinet/in.h>
38 #include "netlink-protocol.h"
39 #include "openvswitch/types.h"
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);
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);
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
,
78 void nl_msg_put_string(struct ofpbuf
*, uint16_t type
, const char *value
);
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_cancel_nested(struct ofpbuf
*, size_t offset
);
83 bool nl_msg_end_non_empty_nested(struct ofpbuf
*, size_t offset
);
84 void nl_msg_put_nested(struct ofpbuf
*, uint16_t type
,
85 const void *data
, size_t size
);
87 /* Prepending attributes. */
88 void *nl_msg_push_unspec_uninit(struct ofpbuf
*, uint16_t type
, size_t);
89 void nl_msg_push_unspec(struct ofpbuf
*, uint16_t type
, const void *, size_t);
90 void nl_msg_push_flag(struct ofpbuf
*, uint16_t type
);
91 void nl_msg_push_u8(struct ofpbuf
*, uint16_t type
, uint8_t value
);
92 void nl_msg_push_u16(struct ofpbuf
*, uint16_t type
, uint16_t value
);
93 void nl_msg_push_u32(struct ofpbuf
*, uint16_t type
, uint32_t value
);
94 void nl_msg_push_u64(struct ofpbuf
*, uint16_t type
, uint64_t value
);
95 void nl_msg_push_be16(struct ofpbuf
*, uint16_t type
, ovs_be16 value
);
96 void nl_msg_push_be32(struct ofpbuf
*, uint16_t type
, ovs_be32 value
);
97 void nl_msg_push_be64(struct ofpbuf
*, uint16_t type
, ovs_be64 value
);
98 void nl_msg_push_string(struct ofpbuf
*, uint16_t type
, const char *value
);
100 /* Separating buffers into individual messages. */
101 struct nlmsghdr
*nl_msg_next(struct ofpbuf
*buffer
, struct ofpbuf
*msg
);
103 /* Sizes of various attribute types, in bytes, including the attribute header
106 * A minimum-size attribute is 4 bytes long: 4 bytes of header, no bytes of
107 * payload, no padding.
109 * A maximum-size attribute is 65536 bytes long: 4 bytes of header, 65531 bytes
110 * of payload, 1 byte of padding. (Thus, NL_ATTR_SIZE() of a maximum length
111 * attribute payload does not fit in 16 bits.) */
112 #define NL_ATTR_SIZE(PAYLOAD_SIZE) (NLA_HDRLEN + NLA_ALIGN(PAYLOAD_SIZE))
113 #define NL_A_U8_SIZE NL_ATTR_SIZE(sizeof(uint8_t))
114 #define NL_A_U16_SIZE NL_ATTR_SIZE(sizeof(uint16_t))
115 #define NL_A_U32_SIZE NL_ATTR_SIZE(sizeof(uint32_t))
116 #define NL_A_U64_SIZE NL_ATTR_SIZE(sizeof(uint64_t))
117 #define NL_A_BE16_SIZE NL_ATTR_SIZE(sizeof(ovs_be16))
118 #define NL_A_BE32_SIZE NL_ATTR_SIZE(sizeof(ovs_be32))
119 #define NL_A_BE64_SIZE NL_ATTR_SIZE(sizeof(ovs_be64))
120 #define NL_A_FLAG_SIZE NL_ATTR_SIZE(0)
121 #define NL_A_IPV6_SIZE NL_ATTR_SIZE(sizeof(struct in6_addr))
123 bool nl_attr_oversized(size_t payload_size
);
125 /* Netlink attribute types. */
132 NL_A_BE16
= NL_A_U16
,
134 NL_A_BE32
= NL_A_U32
,
136 NL_A_BE64
= NL_A_U64
,
144 /* Netlink attribute iteration. */
145 static inline struct nlattr
*
146 nl_attr_next(const struct nlattr
*nla
)
148 return (void *) ((uint8_t *) nla
+ NLA_ALIGN(nla
->nla_len
));
152 nl_attr_is_valid(const struct nlattr
*nla
, size_t maxlen
)
154 return (maxlen
>= sizeof *nla
155 && nla
->nla_len
>= sizeof *nla
156 && nla
->nla_len
<= maxlen
);
160 nl_attr_len_pad(const struct nlattr
*nla
, size_t maxlen
)
162 size_t len
= NLA_ALIGN(nla
->nla_len
);
164 return len
<= maxlen
? len
: nla
->nla_len
;
167 /* This macro is careful to check for attributes with bad lengths. */
168 #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \
169 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
170 nl_attr_is_valid(ITER, LEFT); \
171 (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER))
174 /* This macro does not check for attributes with bad lengths. It should only
175 * be used with messages from trusted sources or with messages that have
176 * already been validated (e.g. with NL_ATTR_FOR_EACH). */
177 #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \
178 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
180 (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER))
182 /* These variants are convenient for iterating nested attributes. */
183 #define NL_NESTED_FOR_EACH(ITER, LEFT, A) \
184 NL_ATTR_FOR_EACH(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
185 #define NL_NESTED_FOR_EACH_UNSAFE(ITER, LEFT, A) \
186 NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A))
188 /* Netlink attribute parsing. */
189 int nl_attr_type(const struct nlattr
*);
190 const void *nl_attr_get(const struct nlattr
*);
191 size_t nl_attr_get_size(const struct nlattr
*);
192 const void *nl_attr_get_unspec(const struct nlattr
*, size_t size
);
193 bool nl_attr_get_flag(const struct nlattr
*);
194 uint8_t nl_attr_get_u8(const struct nlattr
*);
195 uint16_t nl_attr_get_u16(const struct nlattr
*);
196 uint32_t nl_attr_get_u32(const struct nlattr
*);
197 uint64_t nl_attr_get_u64(const struct nlattr
*);
198 ovs_be16
nl_attr_get_be16(const struct nlattr
*);
199 ovs_be32
nl_attr_get_be32(const struct nlattr
*);
200 ovs_be64
nl_attr_get_be64(const struct nlattr
*);
201 struct in6_addr
nl_attr_get_in6_addr(const struct nlattr
*nla
);
202 odp_port_t
nl_attr_get_odp_port(const struct nlattr
*);
203 const char *nl_attr_get_string(const struct nlattr
*);
204 void nl_attr_get_nested(const struct nlattr
*, struct ofpbuf
*);
206 /* Netlink attribute policy.
208 * Specifies how to parse a single attribute from a Netlink message payload.
212 enum nl_attr_type type
;
213 size_t min_len
, max_len
;
217 #define NL_POLICY_FOR(TYPE) \
218 .type = NL_A_UNSPEC, .min_len = sizeof(TYPE), .max_len = sizeof(TYPE)
220 bool nl_attr_validate(const struct nlattr
*, const struct nl_policy
*);
222 bool nl_policy_parse(const struct ofpbuf
*, size_t offset
,
223 const struct nl_policy
[],
224 struct nlattr
*[], size_t n_attrs
);
225 bool nl_parse_nested(const struct nlattr
*, const struct nl_policy
[],
226 struct nlattr
*[], size_t n_attrs
);
228 const struct nlattr
*nl_attr_find(const struct ofpbuf
*, size_t hdr_len
,
230 const struct nlattr
*nl_attr_find_nested(const struct nlattr
*, uint16_t type
);
231 const struct nlattr
*nl_attr_find__(const struct nlattr
*attrs
, size_t size
,
234 #endif /* netlink.h */