lib/netlink-socket.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
   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_SOCKET_H
  18 #define NETLINK_SOCKET_H 1
  19
  20 /* Netlink socket definitions.
  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 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,
  32  * see netlink.h.
  33  */
  34
  35 #include <stdbool.h>
  36 #include <stddef.h>
  37 #include <stdint.h>
  38
  39 struct ofpbuf;
  40 struct nl_sock;
  41
  42 #ifndef HAVE_NETLINK
  43 #error "netlink-socket.h is only for hosts that support Netlink sockets"
  44 #endif
  45
  46 /* Netlink sockets. */
  47 int nl_sock_create(int protocol, struct nl_sock **);
  48 int nl_sock_clone(const struct nl_sock *, struct nl_sock **);
  49 void nl_sock_destroy(struct nl_sock *);
  50
  51 int nl_sock_join_mcgroup(struct nl_sock *, unsigned int multicast_group);
  52 int nl_sock_leave_mcgroup(struct nl_sock *, unsigned int multicast_group);
  53
  54 int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
  55 int nl_sock_recv(struct nl_sock *, struct ofpbuf **, bool wait);
  56 int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
  57                      struct ofpbuf **reply);
  58
  59 int nl_sock_drain(struct nl_sock *);
  60
  61 void nl_sock_wait(const struct nl_sock *, short int events);
  62 int nl_sock_fd(const struct nl_sock *);
  63
  64 uint32_t nl_sock_pid(const struct nl_sock *);
  65
  66 /* Batching transactions. */
  67 struct nl_transaction {
  68     /* Filled in by client. */
  69     struct ofpbuf *request;     /* Request to send. */
  70
  71     /* Filled in by nl_sock_transact_batch(). */
  72     struct ofpbuf *reply;       /* Reply (NULL if reply was an error code). */
  73     int error;                  /* Positive errno value, 0 if no error. */
  74 };
  75
  76 void nl_sock_transact_multiple(struct nl_sock *,
  77                                struct nl_transaction **, size_t n);
  78
  79 /* Table dumping. */
  80 struct nl_dump {
  81     struct nl_sock *sock;       /* Socket being dumped. */
  82     uint32_t seq;               /* Expected nlmsg_seq for replies. */
  83     struct ofpbuf *buffer;      /* Receive buffer currently being iterated. */
  84     int status;                 /* 0=OK, EOF=done, or positive errno value. */
  85 };
  86
  87 void nl_dump_start(struct nl_dump *, struct nl_sock *,
  88                    const struct ofpbuf *request);
  89 bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply);
  90 int nl_dump_done(struct nl_dump *);
  91
  92 /* Miscellaneous */
  93 int nl_lookup_genl_family(const char *name, int *number);
  94 int nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
  95                            unsigned int *multicast_group,
  96                            unsigned int fallback);
  97
  98 #endif /* netlink-socket.h */