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git.proxmox.com Git - mirror_ovs.git/blob - lib/netlink-notifier.c
2 * Copyright (c) 2009, 2010, 2011, 2012, 2013 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.
19 #include "netlink-notifier.h"
27 #include "netlink-socket.h"
28 #include "openvswitch/ofpbuf.h"
29 #include "openvswitch/vlog.h"
31 VLOG_DEFINE_THIS_MODULE(netlink_notifier
);
33 COVERAGE_DEFINE(nln_changed
);
35 static void nln_report(struct nln
*nln
, void *change
);
38 struct nl_sock
*notify_sock
; /* Netlink socket. */
39 struct ovs_list all_notifiers
; /* All nln notifiers. */
40 bool has_run
; /* Guard for run and wait functions. */
42 /* Passed in by nln_create(). */
43 int multicast_group
; /* Multicast group we listen on. */
44 int protocol
; /* Protocol passed to nl_sock_create(). */
45 nln_parse_func
*parse
; /* Message parsing function. */
46 void *change
; /* Change passed to parse. */
50 struct nln
*nln
; /* Parent nln. */
57 /* Creates an nln handle which may be used to manage change notifications. The
58 * created handle will listen for netlink messages on 'multicast_group' using
59 * netlink protocol 'protocol' (e.g. NETLINK_ROUTE, NETLINK_GENERIC, ...).
60 * Incoming messages will be parsed with 'parse' which will be passed 'change'
63 nln_create(int protocol
, int multicast_group
, nln_parse_func
*parse
,
68 nln
= xzalloc(sizeof *nln
);
69 nln
->notify_sock
= NULL
;
70 nln
->protocol
= protocol
;
71 nln
->multicast_group
= multicast_group
;
76 ovs_list_init(&nln
->all_notifiers
);
80 /* Destroys 'nln' by freeing any memory it has reserved and closing any sockets
83 * The caller is responsible for destroying any notifiers created by this
84 * 'nln' before destroying 'nln'. */
86 nln_destroy(struct nln
*nln
)
89 ovs_assert(ovs_list_is_empty(&nln
->all_notifiers
));
90 nl_sock_destroy(nln
->notify_sock
);
95 /* Registers 'cb' to be called with auxiliary data 'aux' with change
96 * notifications. The notifier is stored in 'notifier', which the caller must
99 * This is probably not the function you want. You should probably be using
100 * message specific notifiers like rtnetlink_link_notifier_register().
102 * Returns an initialized nln_notifier if successful, otherwise NULL. */
103 struct nln_notifier
*
104 nln_notifier_create(struct nln
*nln
, nln_notify_func
*cb
, void *aux
)
106 struct nln_notifier
*notifier
;
108 if (!nln
->notify_sock
) {
109 struct nl_sock
*sock
;
112 error
= nl_sock_create(nln
->protocol
, &sock
);
114 error
= nl_sock_join_mcgroup(sock
, nln
->multicast_group
);
117 nl_sock_destroy(sock
);
118 VLOG_WARN("could not create netlink socket: %s",
119 ovs_strerror(error
));
122 nln
->notify_sock
= sock
;
124 /* Catch up on notification work so that the new notifier won't
125 * receive any stale notifications. */
129 notifier
= xmalloc(sizeof *notifier
);
130 ovs_list_push_back(&nln
->all_notifiers
, ¬ifier
->node
);
137 /* Destroys 'notifier', which must have previously been created with
138 * nln_notifier_register(). */
140 nln_notifier_destroy(struct nln_notifier
*notifier
)
143 struct nln
*nln
= notifier
->nln
;
145 ovs_list_remove(¬ifier
->node
);
146 if (ovs_list_is_empty(&nln
->all_notifiers
)) {
147 nl_sock_destroy(nln
->notify_sock
);
148 nln
->notify_sock
= NULL
;
154 /* Calls all of the registered notifiers, passing along any as-yet-unreported
157 nln_run(struct nln
*nln
)
159 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(1, 5);
161 if (!nln
->notify_sock
|| nln
->has_run
) {
167 uint64_t buf_stub
[4096 / 8];
171 ofpbuf_use_stub(&buf
, buf_stub
, sizeof buf_stub
);
172 error
= nl_sock_recv(nln
->notify_sock
, &buf
, false);
174 if (nln
->parse(&buf
, nln
->change
)) {
175 nln_report(nln
, nln
->change
);
177 VLOG_WARN_RL(&rl
, "received bad netlink message");
178 nln_report(nln
, NULL
);
181 } else if (error
== EAGAIN
) {
184 if (error
== ENOBUFS
) {
185 /* The socket buffer might be full, there could be too many
186 * notifications, so it makes sense to call nln_report() */
187 nln_report(nln
, NULL
);
188 VLOG_WARN_RL(&rl
, "netlink receive buffer overflowed");
190 VLOG_WARN_RL(&rl
, "error reading netlink socket: %s",
191 ovs_strerror(error
));
198 /* Causes poll_block() to wake up when change notifications are ready. */
200 nln_wait(struct nln
*nln
)
202 nln
->has_run
= false;
203 if (nln
->notify_sock
) {
204 nl_sock_wait(nln
->notify_sock
, POLLIN
);
209 nln_report(struct nln
*nln
, void *change
)
211 struct nln_notifier
*notifier
;
214 COVERAGE_INC(nln_changed
);
217 LIST_FOR_EACH (notifier
, node
, &nln
->all_notifiers
) {
218 notifier
->cb(change
, notifier
->aux
);