2 * Copyright (c) 2008, 2009, 2010 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 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);
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);
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);
69 void nl_msg_put_string(struct ofpbuf *, uint16_t type, const char *value);
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);
76 /* Separating buffers into individual messages. */
77 struct nlmsghdr *nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg);
79 /* Netlink attribute types. */
94 /* Netlink attribute iteration. */
95 static inline struct nlattr *
96 nl_attr_next(const struct nlattr *nla)
98 return (struct nlattr *) ((uint8_t *) nla + NLA_ALIGN(nla->nla_len));
102 nl_attr_is_valid(const struct nlattr *nla, size_t maxlen)
104 return (maxlen >= sizeof *nla
105 && nla->nla_len >= sizeof *nla
106 && NLA_ALIGN(nla->nla_len) <= maxlen);
109 /* This macro is careful to check for attributes with bad lengths. */
110 #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \
111 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
112 nl_attr_is_valid(ITER, LEFT); \
113 (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER))
116 /* This macro does not check for attributes with bad lengths. It should only
117 * be used with messages from trusted sources or with messages that have
118 * already been validates (e.g. with NL_ATTR_FOR_EACH). */
119 #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \
120 for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \
122 (LEFT) -= NLA_ALIGN((ITER)->nla_len), (ITER) = nl_attr_next(ITER))
124 /* Netlink attribute parsing. */
125 int nl_attr_type(const struct nlattr *);
126 const void *nl_attr_get(const struct nlattr *);
127 size_t nl_attr_get_size(const struct nlattr *);
128 const void *nl_attr_get_unspec(const struct nlattr *, size_t size);
129 bool nl_attr_get_flag(const struct nlattr *);
130 uint8_t nl_attr_get_u8(const struct nlattr *);
131 uint16_t nl_attr_get_u16(const struct nlattr *);
132 uint32_t nl_attr_get_u32(const struct nlattr *);
133 uint64_t nl_attr_get_u64(const struct nlattr *);
134 ovs_be16 nl_attr_get_be16(const struct nlattr *);
135 ovs_be32 nl_attr_get_be32(const struct nlattr *);
136 ovs_be64 nl_attr_get_be64(const struct nlattr *);
137 const char *nl_attr_get_string(const struct nlattr *);
138 void nl_attr_get_nested(const struct nlattr *, struct ofpbuf *);
140 /* Netlink attribute policy.
142 * Specifies how to parse a single attribute from a Netlink message payload.
146 enum nl_attr_type type;
147 size_t min_len, max_len;
151 bool nl_policy_parse(const struct ofpbuf *, size_t offset,
152 const struct nl_policy[],
153 struct nlattr *[], size_t n_attrs);
154 bool nl_parse_nested(const struct nlattr *, const struct nl_policy[],
155 struct nlattr *[], size_t n_attrs);
157 #endif /* netlink.h */