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ovs/lib/netlink-socket.h
Ben Pfaff a88b4e0412 netlink-socket: Simplify use of transactions and dumps.
This disentangles "struct nl_dump" from "struct nl_sock", clearing the way
to make the use of either one thread-safe in an obviously correct manner.

Signed-off-by: Ben Pfaff <blp@nicira.com>
2013-07-18 13:18:46 -07:00

112 lines
4.0 KiB
C

/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef NETLINK_SOCKET_H
#define NETLINK_SOCKET_H 1
/* Netlink socket definitions.
*
* Netlink is a datagram-based network protocol primarily for communication
* between user processes and the kernel, and mainly on Linux. Netlink is
* specified in RFC 3549, "Linux Netlink as an IP Services Protocol".
*
* Netlink is not suitable for use in physical networks of heterogeneous
* machines because host byte order is used throughout.
*
* This header file defines functions for working with Netlink sockets, which
* are Linux-specific. For Netlink protocol definitions, see
* netlink-protocol.h. For helper functions for working with Netlink messages,
* see netlink.h.
*/
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "ofpbuf.h"
struct nl_sock;
#ifndef HAVE_NETLINK
#error "netlink-socket.h is only for hosts that support Netlink sockets"
#endif
/* Netlink sockets. */
int nl_sock_create(int protocol, struct nl_sock **);
int nl_sock_clone(const struct nl_sock *, struct nl_sock **);
void nl_sock_destroy(struct nl_sock *);
int nl_sock_join_mcgroup(struct nl_sock *, unsigned int multicast_group);
int nl_sock_leave_mcgroup(struct nl_sock *, unsigned int multicast_group);
int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
int nl_sock_send_seq(struct nl_sock *, const struct ofpbuf *,
uint32_t nlmsg_seq, bool wait);
int nl_sock_recv(struct nl_sock *, struct ofpbuf *, bool wait);
int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
struct ofpbuf **replyp);
int nl_sock_drain(struct nl_sock *);
void nl_sock_wait(const struct nl_sock *, short int events);
int nl_sock_fd(const struct nl_sock *);
uint32_t nl_sock_pid(const struct nl_sock *);
/* Batching transactions. */
struct nl_transaction {
/* Filled in by client. */
struct ofpbuf *request; /* Request to send. */
/* The client must initialize 'reply' to one of:
*
* - NULL, if it does not care to examine the reply.
*
* - Otherwise, to an ofpbuf with a memory allocation of at least
* NLMSG_HDRLEN bytes.
*/
struct ofpbuf *reply; /* Reply (empty if reply was an error code). */
int error; /* Positive errno value, 0 if no error. */
};
void nl_sock_transact_multiple(struct nl_sock *,
struct nl_transaction **, size_t n);
/* Transactions without an allocated socket. */
int nl_transact(int protocol, const struct ofpbuf *request,
struct ofpbuf **replyp);
void nl_transact_multiple(int protocol, struct nl_transaction **, size_t n);
/* Table dumping. */
struct nl_dump {
struct nl_sock *sock; /* Socket being dumped. */
uint32_t seq; /* Expected nlmsg_seq for replies. */
struct ofpbuf buffer; /* Receive buffer currently being iterated. */
int status; /* 0=OK, EOF=done, or positive errno value. */
};
void nl_dump_start(struct nl_dump *, int protocol,
const struct ofpbuf *request);
bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply);
int nl_dump_done(struct nl_dump *);
/* Miscellaneous */
int nl_lookup_genl_family(const char *name, int *number);
int nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
unsigned int *multicast_group,
unsigned int fallback);
#endif /* netlink-socket.h */