2 * Copyright (c) 2009, 2010, 2011, 2012 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"
28 #include "netlink-socket.h"
32 VLOG_DEFINE_THIS_MODULE(netlink_notifier);
34 COVERAGE_DEFINE(nln_changed);
36 static void nln_report(struct nln *nln, void *change);
39 struct nl_sock *notify_sock; /* Netlink socket. */
40 struct list all_notifiers; /* All nln notifiers. */
41 bool has_run; /* Guard for run and wait functions. */
43 /* Passed in by nln_create(). */
44 int multicast_group; /* Multicast group we listen on. */
45 int protocol; /* Protocal passed to nl_sock_create(). */
46 nln_parse_func *parse; /* Message parsing function. */
47 void *change; /* Change passed to parse. */
51 struct nln *nln; /* Parent nln. */
58 /* Creates an nln handle which may be used to manage change notifications. The
59 * created handle will listen for netlink messages on 'multicast_group' using
60 * netlink protocol 'protocol' (e.g. NETLINK_ROUTE, NETLINK_GENERIC, ...).
61 * Incoming messages will be parsed with 'parse' which will be passed 'change'
64 nln_create(int protocol, int multicast_group, nln_parse_func *parse,
69 nln = xzalloc(sizeof *nln);
70 nln->notify_sock = NULL;
71 nln->protocol = protocol;
72 nln->multicast_group = multicast_group;
77 list_init(&nln->all_notifiers);
81 /* Destroys 'nln' by freeing any memory it has reserved and closing any sockets
84 * The caller is responsible for destroying any notifiers created by this
85 * 'nln' before destroying 'nln'. */
87 nln_destroy(struct nln *nln)
90 assert(list_is_empty(&nln->all_notifiers));
91 nl_sock_destroy(nln->notify_sock);
96 /* Registers 'cb' to be called with auxiliary data 'aux' with change
97 * notifications. The notifier is stored in 'notifier', which the caller must
100 * This is probably not the function you want. You should probably be using
101 * message specific notifiers like rtnetlink_link_notifier_register().
103 * Returns an initialized nln_notifier if successful, otherwise NULL. */
104 struct nln_notifier *
105 nln_notifier_create(struct nln *nln, nln_notify_func *cb, void *aux)
107 struct nln_notifier *notifier;
109 if (!nln->notify_sock) {
110 struct nl_sock *sock;
113 error = nl_sock_create(nln->protocol, &sock);
115 error = nl_sock_join_mcgroup(sock, nln->multicast_group);
118 nl_sock_destroy(sock);
119 VLOG_WARN("could not create netlink socket: %s", 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 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 list_remove(¬ifier->node);
146 if (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 VLOG_WARN_RL(&rl, "netlink receive buffer overflowed");
187 VLOG_WARN_RL(&rl, "error reading netlink socket: %s",
190 nln_report(nln, NULL);
195 /* Causes poll_block() to wake up when change notifications are ready. */
197 nln_wait(struct nln *nln)
199 nln->has_run = false;
200 if (nln->notify_sock) {
201 nl_sock_wait(nln->notify_sock, POLLIN);
206 nln_report(struct nln *nln, void *change)
208 struct nln_notifier *notifier;
211 COVERAGE_INC(nln_changed);
214 LIST_FOR_EACH (notifier, node, &nln->all_notifiers) {
215 notifier->cb(change, notifier->aux);