2 * Copyright (c) 2009, 2010 Nicira Networks.
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 "rtnetlink.h"
26 #include "netlink-socket.h"
30 VLOG_DEFINE_THIS_MODULE(rtnetlink);
32 COVERAGE_DEFINE(rtnetlink_changed);
34 static void rtnetlink_report(struct rtnetlink *rtn, void *change);
37 struct nl_sock *notify_sock; /* Rtnetlink socket. */
38 struct list all_notifiers; /* All rtnetlink notifiers. */
40 /* Passed in by rtnetlink_create(). */
41 int multicast_group; /* Multicast group we listen on. */
42 rtnetlink_parse_func *parse; /* Message parsing function. */
43 void *change; /* Change passed to parse. */
46 /* Creates an rtnetlink handle which may be used to manage change
47 * notifications. The created handle will listen for rtnetlink messages on
48 * 'multicast_group'. Incoming messages will be parsed with 'parse' which will
49 * be passed 'change' as an argument. */
51 rtnetlink_create(int multicast_group, rtnetlink_parse_func *parse,
54 struct rtnetlink *rtn;
56 rtn = xzalloc(sizeof *rtn);
58 rtn->multicast_group = multicast_group;
62 list_init(&rtn->all_notifiers);
66 /* Registers 'cb' to be called with auxiliary data 'aux' with change
67 * notifications. The notifier is stored in 'notifier', which the caller must
70 * This is probably not the function you want. You should probably be using
71 * message specific notifiers like rtnetlink_link_notifier_register().
73 * Returns 0 if successful, otherwise a positive errno value. */
75 rtnetlink_notifier_register(struct rtnetlink *rtn,
76 struct rtnetlink_notifier *notifier,
77 rtnetlink_notify_func *cb, void *aux)
79 if (!rtn->notify_sock) {
80 int error = nl_sock_create(NETLINK_ROUTE, rtn->multicast_group, 0, 0,
83 VLOG_WARN("could not create rtnetlink socket: %s",
88 /* Catch up on notification work so that the new notifier won't
89 * receive any stale notifications. */
90 rtnetlink_notifier_run(rtn);
93 list_push_back(&rtn->all_notifiers, ¬ifier->node);
99 /* Cancels notification on 'notifier', which must have previously been
100 * registered with rtnetlink_notifier_register(). */
102 rtnetlink_notifier_unregister(struct rtnetlink *rtn,
103 struct rtnetlink_notifier *notifier)
105 list_remove(¬ifier->node);
106 if (list_is_empty(&rtn->all_notifiers)) {
107 nl_sock_destroy(rtn->notify_sock);
108 rtn->notify_sock = NULL;
112 /* Calls all of the registered notifiers, passing along any as-yet-unreported
115 rtnetlink_notifier_run(struct rtnetlink *rtn)
117 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
119 if (!rtn->notify_sock) {
127 error = nl_sock_recv(rtn->notify_sock, &buf, false);
129 if (rtn->parse(buf, rtn->change)) {
130 rtnetlink_report(rtn, rtn->change);
132 VLOG_WARN_RL(&rl, "received bad rtnl message");
133 rtnetlink_report(rtn, NULL);
136 } else if (error == EAGAIN) {
139 if (error == ENOBUFS) {
140 VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
142 VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
145 rtnetlink_report(rtn, NULL);
150 /* Causes poll_block() to wake up when change notifications are ready. */
152 rtnetlink_notifier_wait(struct rtnetlink *rtn)
154 if (rtn->notify_sock) {
155 nl_sock_wait(rtn->notify_sock, POLLIN);
160 rtnetlink_report(struct rtnetlink *rtn, void *change)
162 struct rtnetlink_notifier *notifier;
165 COVERAGE_INC(rtnetlink_changed);
168 LIST_FOR_EACH (notifier, node, &rtn->all_notifiers) {
169 notifier->cb(change, notifier->aux);