lib/netlink-socket.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   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  * Thread-safety
  36  * =============
  37  *
  38  * Only a single thread may use a given nl_sock or nl_dump at one time.
  39  */
  40
  41 #include <stdbool.h>
  42 #include <stddef.h>
  43 #include <stdint.h>
  44 #include "ofpbuf.h"
  45
  46 struct nl_sock;
  47
  48 #ifndef HAVE_NETLINK
  49 #error "netlink-socket.h is only for hosts that support Netlink sockets"
  50 #endif
  51
  52 /* Netlink sockets. */
  53 int nl_sock_create(int protocol, struct nl_sock **);
  54 int nl_sock_clone(const struct nl_sock *, struct nl_sock **);
  55 void nl_sock_destroy(struct nl_sock *);
  56
  57 int nl_sock_join_mcgroup(struct nl_sock *, unsigned int multicast_group);
  58 int nl_sock_leave_mcgroup(struct nl_sock *, unsigned int multicast_group);
  59
  60 int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
  61 int nl_sock_send_seq(struct nl_sock *, const struct ofpbuf *,
  62                      uint32_t nlmsg_seq, bool wait);
  63 int nl_sock_recv(struct nl_sock *, struct ofpbuf *, bool wait);
  64 int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
  65                      struct ofpbuf **replyp);
  66
  67 int nl_sock_drain(struct nl_sock *);
  68
  69 void nl_sock_wait(const struct nl_sock *, short int events);
  70 int nl_sock_fd(const struct nl_sock *);
  71
  72 uint32_t nl_sock_pid(const struct nl_sock *);
  73
  74 /* Batching transactions. */
  75 struct nl_transaction {
  76     /* Filled in by client. */
  77     struct ofpbuf *request;     /* Request to send. */
  78
  79     /* The client must initialize 'reply' to one of:
  80      *
  81      *   - NULL, if it does not care to examine the reply.
  82      *
  83      *   - Otherwise, to an ofpbuf with a memory allocation of at least
  84      *     NLMSG_HDRLEN bytes.
  85      */
  86     struct ofpbuf *reply;       /* Reply (empty if reply was an error code). */
  87     int error;                  /* Positive errno value, 0 if no error. */
  88 };
  89
  90 void nl_sock_transact_multiple(struct nl_sock *,
  91                                struct nl_transaction **, size_t n);
  92
  93 /* Transactions without an allocated socket. */
  94 int nl_transact(int protocol, const struct ofpbuf *request,
  95                 struct ofpbuf **replyp);
  96 void nl_transact_multiple(int protocol, struct nl_transaction **, size_t n);
  97
  98 /* Table dumping. */
  99 struct nl_dump {
 100     struct nl_sock *sock;       /* Socket being dumped. */
 101     uint32_t seq;               /* Expected nlmsg_seq for replies. */
 102     struct ofpbuf buffer;       /* Receive buffer currently being iterated. */
 103     int status;                 /* 0=OK, EOF=done, or positive errno value. */
 104 };
 105
 106 void nl_dump_start(struct nl_dump *, int protocol,
 107                    const struct ofpbuf *request);
 108 bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply);
 109 int nl_dump_done(struct nl_dump *);
 110
 111 /* Miscellaneous */
 112 int nl_lookup_genl_family(const char *name, int *number);
 113 int nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
 114                            unsigned int *multicast_group);
 115
 116 #endif /* netlink-socket.h */