2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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.
17 #ifndef NETLINK_SOCKET_H
18 #define NETLINK_SOCKET_H 1
20 /* Netlink socket definitions.
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 functions for working with Netlink sockets, which
30 * are Linux-specific. For Netlink protocol definitions, see
31 * netlink-protocol.h. For helper functions for working with Netlink messages,
38 * Most of the netlink functions are not fully thread-safe: Only a single
39 * thread may use a given nl_sock or nl_dump at one time. The exceptions are:
41 * - nl_sock_recv() is conditionally thread-safe: it may be called from
42 * different threads with the same nl_sock, but each caller must provide
43 * an independent receive buffer.
45 * - nl_dump_next() is conditionally thread-safe: it may be called from
46 * different threads with the same nl_dump, but each caller must provide
47 * independent buffers.
54 #include "ovs-atomic.h"
59 #error "netlink-socket.h is only for hosts that support Netlink sockets"
62 /* Netlink sockets. */
63 int nl_sock_create(int protocol, struct nl_sock **);
64 int nl_sock_clone(const struct nl_sock *, struct nl_sock **);
65 void nl_sock_destroy(struct nl_sock *);
67 int nl_sock_join_mcgroup(struct nl_sock *, unsigned int multicast_group);
68 int nl_sock_leave_mcgroup(struct nl_sock *, unsigned int multicast_group);
70 int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
71 int nl_sock_send_seq(struct nl_sock *, const struct ofpbuf *,
72 uint32_t nlmsg_seq, bool wait);
73 int nl_sock_recv(struct nl_sock *, struct ofpbuf *, bool wait);
74 int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
75 struct ofpbuf **replyp);
77 int nl_sock_drain(struct nl_sock *);
79 void nl_sock_wait(const struct nl_sock *, short int events);
80 int nl_sock_fd(const struct nl_sock *);
82 uint32_t nl_sock_pid(const struct nl_sock *);
84 /* Batching transactions. */
85 struct nl_transaction {
86 /* Filled in by client. */
87 struct ofpbuf *request; /* Request to send. */
89 /* The client must initialize 'reply' to one of:
91 * - NULL, if it does not care to examine the reply.
93 * - Otherwise, to an ofpbuf with a memory allocation of at least
96 struct ofpbuf *reply; /* Reply (empty if reply was an error code). */
97 int error; /* Positive errno value, 0 if no error. */
100 void nl_sock_transact_multiple(struct nl_sock *,
101 struct nl_transaction **, size_t n);
103 /* Transactions without an allocated socket. */
104 int nl_transact(int protocol, const struct ofpbuf *request,
105 struct ofpbuf **replyp);
106 void nl_transact_multiple(int protocol, struct nl_transaction **, size_t n);
109 #define NL_DUMP_BUFSIZE 4096
112 struct nl_sock *sock; /* Socket being dumped. */
113 uint32_t nl_seq; /* Expected nlmsg_seq for replies. */
114 atomic_uint status; /* Low bit set if we read final message.
115 * Other bits hold an errno (0 for success). */
116 struct seq *status_seq; /* Tracks changes to the above 'status'. */
119 void nl_dump_start(struct nl_dump *, int protocol,
120 const struct ofpbuf *request);
121 bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply, struct ofpbuf *buf);
122 int nl_dump_done(struct nl_dump *);
125 int nl_lookup_genl_family(const char *name, int *number);
126 int nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
127 unsigned int *multicast_group);
129 #endif /* netlink-socket.h */