2 * Copyright (c) 2008, 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.
18 #include "fail-open.h"
21 #include "classifier.h"
24 #include "mac-learning.h"
29 #include "ofproto-provider.h"
31 #include "poll-loop.h"
37 VLOG_DEFINE_THIS_MODULE(fail_open);
42 * In fail-open mode, the switch detects when the controller cannot be
43 * contacted or when the controller is dropping switch connections because the
44 * switch does not pass its admission control policy. In those situations the
45 * switch sets up flows itself using the "normal" action.
47 * There is a little subtlety to implementation, to properly handle the case
48 * where the controller allows switch connections but drops them a few seconds
49 * later for admission control reasons. Because of this case, we don't want to
50 * just stop setting up flows when we connect to the controller: if we did,
51 * then new flow setup and existing flows would stop during the duration of
52 * connection to the controller, and thus the whole network would go down for
53 * that period of time.
55 * So, instead, we add some special cases when we are connected to a
56 * controller, but not yet sure that it has admitted us:
58 * - We set up flows immediately ourselves, but simultaneously send out an
59 * OFPT_PACKET_IN to the controller. We put a special bogus buffer-id in
60 * these OFPT_PACKET_IN messages so that duplicate packets don't get sent
61 * out to the network when the controller replies.
63 * - We also send out OFPT_PACKET_IN messages for totally bogus packets
64 * every so often, in case no real new flows are arriving in the network.
66 * - We don't flush the flow table at the time we connect, because this
67 * could cause network stuttering in a switch with lots of flows or very
68 * high-bandwidth flows by suddenly throwing lots of packets down to
73 struct ofproto *ofproto;
74 struct connmgr *connmgr;
75 int last_disconn_secs;
76 long long int next_bogus_packet_in;
77 struct rconn_packet_counter *bogus_packet_counter;
80 static void fail_open_recover(struct fail_open *);
82 /* Returns the number of seconds of disconnection after which fail-open mode
85 trigger_duration(const struct fail_open *fo)
87 if (!connmgr_has_controllers(fo->connmgr)) {
88 /* Shouldn't ever arrive here, but if we do, never fail open. */
91 /* Otherwise, every controller must have a chance to send an
92 * inactivity probe and reconnect before we fail open, so take the
93 * maximum probe interval and multiply by 3:
95 * - The first interval is the idle time before sending an inactivity
98 * - The second interval is the time allowed for a response to the
101 * - The third interval is the time allowed to reconnect after no
102 * response is received.
104 return connmgr_get_max_probe_interval(fo->connmgr) * 3;
108 /* Returns true if 'fo' is currently in fail-open mode, otherwise false. */
110 fail_open_is_active(const struct fail_open *fo)
112 return fo->last_disconn_secs != 0;
116 send_bogus_packet_ins(struct fail_open *fo)
118 struct ofputil_packet_in pin;
119 uint8_t mac[ETH_ADDR_LEN];
122 ofpbuf_init(&b, 128);
123 eth_addr_nicira_random(mac);
124 compose_benign_packet(&b, "Open vSwitch Controller Probe", 0xa033, mac);
126 memset(&pin, 0, sizeof pin);
128 pin.packet_len = b.size;
129 pin.reason = OFPR_NO_MATCH;
130 pin.send_len = b.size;
131 pin.fmd.in_port = OFPP_LOCAL;
132 connmgr_send_packet_in(fo->connmgr, &pin);
137 /* Enter fail-open mode if we should be in it. */
139 fail_open_run(struct fail_open *fo)
141 int disconn_secs = connmgr_failure_duration(fo->connmgr);
143 /* Enter fail-open mode if 'fo' is not in it but should be. */
144 if (disconn_secs >= trigger_duration(fo)) {
145 if (!fail_open_is_active(fo)) {
146 VLOG_WARN("Could not connect to controller (or switch failed "
147 "controller's post-connection admission control "
148 "policy) for %d seconds, failing open", disconn_secs);
149 fo->last_disconn_secs = disconn_secs;
151 /* Flush all OpenFlow and datapath flows. We will set up our
152 * fail-open rule from fail_open_flushed() when
153 * ofproto_flush_flows() calls back to us. */
154 ofproto_flush_flows(fo->ofproto);
155 } else if (disconn_secs > fo->last_disconn_secs + 60) {
156 VLOG_INFO("Still in fail-open mode after %d seconds disconnected "
157 "from controller", disconn_secs);
158 fo->last_disconn_secs = disconn_secs;
162 /* Schedule a bogus packet-in if we're connected and in fail-open. */
163 if (fail_open_is_active(fo)) {
164 if (connmgr_is_any_controller_connected(fo->connmgr)) {
165 bool expired = time_msec() >= fo->next_bogus_packet_in;
167 send_bogus_packet_ins(fo);
169 if (expired || fo->next_bogus_packet_in == LLONG_MAX) {
170 fo->next_bogus_packet_in = time_msec() + 2000;
173 fo->next_bogus_packet_in = LLONG_MAX;
179 /* If 'fo' is currently in fail-open mode and its rconn has connected to the
180 * controller, exits fail open mode. */
182 fail_open_maybe_recover(struct fail_open *fo)
184 if (fail_open_is_active(fo)
185 && connmgr_is_any_controller_admitted(fo->connmgr)) {
186 fail_open_recover(fo);
191 fail_open_recover(struct fail_open *fo)
193 struct cls_rule rule;
195 VLOG_WARN("No longer in fail-open mode");
196 fo->last_disconn_secs = 0;
197 fo->next_bogus_packet_in = LLONG_MAX;
199 cls_rule_init_catchall(&rule, FAIL_OPEN_PRIORITY);
200 ofproto_delete_flow(fo->ofproto, &rule);
204 fail_open_wait(struct fail_open *fo)
206 if (fo->next_bogus_packet_in != LLONG_MAX) {
207 poll_timer_wait_until(fo->next_bogus_packet_in);
212 fail_open_flushed(struct fail_open *fo)
214 int disconn_secs = connmgr_failure_duration(fo->connmgr);
215 bool open = disconn_secs >= trigger_duration(fo);
217 union ofp_action action;
218 struct cls_rule rule;
220 /* Set up a flow that matches every packet and directs them to
222 memset(&action, 0, sizeof action);
223 action.type = htons(OFPAT10_OUTPUT);
224 action.output.len = htons(sizeof action);
225 action.output.port = htons(OFPP_NORMAL);
227 cls_rule_init_catchall(&rule, FAIL_OPEN_PRIORITY);
228 ofproto_add_flow(fo->ofproto, &rule, &action, 1);
232 /* Creates and returns a new struct fail_open for 'ofproto' and 'mgr'. */
234 fail_open_create(struct ofproto *ofproto, struct connmgr *mgr)
236 struct fail_open *fo = xmalloc(sizeof *fo);
237 fo->ofproto = ofproto;
239 fo->last_disconn_secs = 0;
240 fo->next_bogus_packet_in = LLONG_MAX;
241 fo->bogus_packet_counter = rconn_packet_counter_create();
247 fail_open_destroy(struct fail_open *fo)
250 if (fail_open_is_active(fo)) {
251 fail_open_recover(fo);
253 /* We don't own fo->connmgr. */
254 rconn_packet_counter_destroy(fo->bogus_packet_counter);