2 * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2016 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(const struct nln *nln, void *change, int group);
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 protocol; /* Protocol passed to nl_sock_create(). */
44 nln_parse_func *parse; /* Message parsing function. */
45 void *change; /* Change passed to parse. */
49 struct ovs_list node; /* In struct nln's 'all_notifiers' list. */
50 struct nln *nln; /* Parent nln. */
52 int multicast_group; /* Multicast group we listen on. */
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, nln_parse_func *parse, void *change)
67 nln = xzalloc(sizeof *nln);
68 nln->notify_sock = NULL;
69 nln->protocol = protocol;
74 ovs_list_init(&nln->all_notifiers);
78 /* Destroys 'nln' by freeing any memory it has reserved and closing any sockets
81 * The caller is responsible for destroying any notifiers created by this
82 * 'nln' before destroying 'nln'. */
84 nln_destroy(struct nln *nln)
87 ovs_assert(ovs_list_is_empty(&nln->all_notifiers));
88 nl_sock_destroy(nln->notify_sock);
93 /* Registers 'cb' to be called with auxiliary data 'aux' with change
94 * notifications. The notifier is stored in 'notifier', which the caller must
97 * This is probably not the function you want. You should probably be using
98 * message specific notifiers like rtnetlink_link_notifier_register().
100 * Returns an initialized nln_notifier if successful, otherwise NULL. */
101 struct nln_notifier *
102 nln_notifier_create(struct nln *nln, int multicast_group, nln_notify_func *cb,
105 struct nln_notifier *notifier;
108 if (!nln->notify_sock) {
109 struct nl_sock *sock;
111 error = nl_sock_create(nln->protocol, &sock);
113 VLOG_WARN("could not create netlink socket: %s",
114 ovs_strerror(error));
117 nln->notify_sock = sock;
119 /* Catch up on notification work so that the new notifier won't
120 * receive any stale notifications. */
124 error = nl_sock_join_mcgroup(nln->notify_sock, multicast_group);
126 VLOG_WARN("could not join netlink multicast group: %s",
127 ovs_strerror(error));
131 notifier = xmalloc(sizeof *notifier);
132 notifier->multicast_group = multicast_group;
137 ovs_list_push_back(&nln->all_notifiers, ¬ifier->node);
142 /* Destroys 'notifier', which must have previously been created with
143 * nln_notifier_register(). */
145 nln_notifier_destroy(struct nln_notifier *notifier)
148 struct nln *nln = notifier->nln;
149 struct nln_notifier *iter;
152 ovs_list_remove(¬ifier->node);
154 /* Leave the group if no other notifier is interested in it. */
155 LIST_FOR_EACH (iter, node, &nln->all_notifiers) {
156 if (iter->multicast_group == notifier->multicast_group) {
161 nl_sock_leave_mcgroup(nln->notify_sock, notifier->multicast_group);
164 if (ovs_list_is_empty(&nln->all_notifiers)) {
165 nl_sock_destroy(nln->notify_sock);
166 nln->notify_sock = NULL;
172 /* Calls all of the registered notifiers, passing along any as-yet-unreported
175 nln_run(struct nln *nln)
177 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
179 if (!nln->notify_sock || nln->has_run) {
185 uint64_t buf_stub[4096 / 8];
189 ofpbuf_use_stub(&buf, buf_stub, sizeof buf_stub);
190 error = nl_sock_recv(nln->notify_sock, &buf, false);
192 int group = nln->parse(&buf, nln->change);
195 nln_report(nln, nln->change, group);
197 VLOG_WARN_RL(&rl, "unexpected netlink message contents");
198 nln_report(nln, NULL, 0);
201 } else if (error == EAGAIN) {
204 if (error == ENOBUFS) {
205 /* The socket buffer might be full, there could be too many
206 * notifications, so it makes sense to call nln_report() */
207 nln_report(nln, NULL, 0);
208 VLOG_WARN_RL(&rl, "netlink receive buffer overflowed");
210 VLOG_WARN_RL(&rl, "error reading netlink socket: %s",
211 ovs_strerror(error));
218 /* Causes poll_block() to wake up when change notifications are ready. */
220 nln_wait(struct nln *nln)
222 nln->has_run = false;
223 if (nln->notify_sock) {
224 nl_sock_wait(nln->notify_sock, POLLIN);
229 nln_report(const struct nln *nln, void *change, int group)
231 struct nln_notifier *notifier;
234 COVERAGE_INC(nln_changed);
237 LIST_FOR_EACH (notifier, node, &nln->all_notifiers) {
238 if (!change || group == notifier->multicast_group) {
239 notifier->cb(change, notifier->aux);