2 * Copyright (c) 2008, 2009 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.
26 #include "openflow/openflow.h"
27 #include "poll-loop.h"
33 #define THIS_MODULE VLM_rconn
38 STATE(BACKOFF, 1 << 1) \
39 STATE(CONNECTING, 1 << 2) \
40 STATE(ACTIVE, 1 << 3) \
43 #define STATE(NAME, VALUE) S_##NAME = VALUE,
49 state_name(enum state state)
52 #define STATE(NAME, VALUE) case S_##NAME: return #NAME;
59 /* A reliable connection to an OpenFlow switch or controller.
61 * See the large comment in rconn.h for more information. */
74 time_t backoff_deadline;
76 time_t last_connected;
77 unsigned int packets_sent;
80 /* In S_ACTIVE and S_IDLE, probably_admitted reports whether we believe
81 * that the peer has made a (positive) admission control decision on our
82 * connection. If we have not yet been (probably) admitted, then the
83 * connection does not reset the timer used for deciding whether the switch
84 * should go into fail-open mode.
86 * last_admitted reports the last time we believe such a positive admission
87 * control decision was made. */
88 bool probably_admitted;
91 /* These values are simply for statistics reporting, not used directly by
92 * anything internal to the rconn (or the secchan for that matter). */
93 unsigned int packets_received;
94 unsigned int n_attempted_connections, n_successful_connections;
96 unsigned long int total_time_connected;
98 /* If we can't connect to the peer, it could be for any number of reasons.
99 * Usually, one would assume it is because the peer is not running or
100 * because the network is partitioned. But it could also be because the
101 * network topology has changed, in which case the upper layer will need to
102 * reassess it (in particular, obtain a new IP address via DHCP and find
103 * the new location of the controller). We set this flag when we suspect
104 * that this could be the case. */
105 bool questionable_connectivity;
106 time_t last_questioned;
108 /* Throughout this file, "probe" is shorthand for "inactivity probe".
109 * When nothing has been received from the peer for a while, we send out
110 * an echo request as an inactivity probe packet. We should receive back
112 int probe_interval; /* Secs of inactivity before sending probe. */
114 /* Messages sent or received are copied to the monitor connections. */
115 #define MAX_MONITORS 8
116 struct vconn *monitors[8];
120 static unsigned int elapsed_in_this_state(const struct rconn *);
121 static unsigned int timeout(const struct rconn *);
122 static bool timed_out(const struct rconn *);
123 static void state_transition(struct rconn *, enum state);
124 static int try_send(struct rconn *);
125 static int reconnect(struct rconn *);
126 static void disconnect(struct rconn *, int error);
127 static void flush_queue(struct rconn *);
128 static void question_connectivity(struct rconn *);
129 static void copy_to_monitor(struct rconn *, const struct ofpbuf *);
130 static bool is_connected_state(enum state);
131 static bool is_admitted_msg(const struct ofpbuf *);
133 /* Creates a new rconn, connects it (reliably) to 'name', and returns it. */
135 rconn_new(const char *name, int inactivity_probe_interval, int max_backoff)
137 struct rconn *rc = rconn_create(inactivity_probe_interval, max_backoff);
138 rconn_connect(rc, name);
142 /* Creates a new rconn, connects it (unreliably) to 'vconn', and returns it. */
144 rconn_new_from_vconn(const char *name, struct vconn *vconn)
146 struct rconn *rc = rconn_create(60, 0);
147 rconn_connect_unreliably(rc, name, vconn);
151 /* Creates and returns a new rconn.
153 * 'probe_interval' is a number of seconds. If the interval passes once
154 * without an OpenFlow message being received from the peer, the rconn sends
155 * out an "echo request" message. If the interval passes again without a
156 * message being received, the rconn disconnects and re-connects to the peer.
157 * Setting 'probe_interval' to 0 disables this behavior.
159 * 'max_backoff' is the maximum number of seconds between attempts to connect
160 * to the peer. The actual interval starts at 1 second and doubles on each
161 * failure until it reaches 'max_backoff'. If 0 is specified, the default of
162 * 8 seconds is used. */
164 rconn_create(int probe_interval, int max_backoff)
166 struct rconn *rc = xcalloc(1, sizeof *rc);
169 rc->state_entered = time_now();
172 rc->name = xstrdup("void");
173 rc->reliable = false;
175 queue_init(&rc->txq);
178 rc->max_backoff = max_backoff ? max_backoff : 8;
179 rc->backoff_deadline = TIME_MIN;
180 rc->last_received = time_now();
181 rc->last_connected = time_now();
184 rc->packets_sent = 0;
186 rc->probably_admitted = false;
187 rc->last_admitted = time_now();
189 rc->packets_received = 0;
190 rc->n_attempted_connections = 0;
191 rc->n_successful_connections = 0;
192 rc->creation_time = time_now();
193 rc->total_time_connected = 0;
195 rc->questionable_connectivity = false;
196 rc->last_questioned = time_now();
198 rconn_set_probe_interval(rc, probe_interval);
206 rconn_set_max_backoff(struct rconn *rc, int max_backoff)
208 rc->max_backoff = MAX(1, max_backoff);
209 if (rc->state == S_BACKOFF && rc->backoff > max_backoff) {
210 rc->backoff = max_backoff;
211 if (rc->backoff_deadline > time_now() + max_backoff) {
212 rc->backoff_deadline = time_now() + max_backoff;
218 rconn_get_max_backoff(const struct rconn *rc)
220 return rc->max_backoff;
224 rconn_set_probe_interval(struct rconn *rc, int probe_interval)
226 rc->probe_interval = probe_interval ? MAX(5, probe_interval) : 0;
230 rconn_get_probe_interval(const struct rconn *rc)
232 return rc->probe_interval;
236 rconn_connect(struct rconn *rc, const char *name)
238 rconn_disconnect(rc);
240 rc->name = xstrdup(name);
242 return reconnect(rc);
246 rconn_connect_unreliably(struct rconn *rc,
247 const char *name, struct vconn *vconn)
249 assert(vconn != NULL);
250 rconn_disconnect(rc);
252 rc->name = xstrdup(name);
253 rc->reliable = false;
255 rc->last_connected = time_now();
256 state_transition(rc, S_ACTIVE);
259 /* If 'rc' is connected, forces it to drop the connection and reconnect. */
261 rconn_reconnect(struct rconn *rc)
263 if (rc->state & (S_ACTIVE | S_IDLE)) {
269 rconn_disconnect(struct rconn *rc)
271 if (rc->state != S_VOID) {
273 vconn_close(rc->vconn);
277 rc->name = xstrdup("void");
278 rc->reliable = false;
281 rc->backoff_deadline = TIME_MIN;
283 state_transition(rc, S_VOID);
287 /* Disconnects 'rc' and frees the underlying storage. */
289 rconn_destroy(struct rconn *rc)
295 vconn_close(rc->vconn);
297 queue_destroy(&rc->txq);
298 for (i = 0; i < rc->n_monitors; i++) {
299 vconn_close(rc->monitors[i]);
306 timeout_VOID(const struct rconn *rc UNUSED)
312 run_VOID(struct rconn *rc UNUSED)
318 reconnect(struct rconn *rc)
322 VLOG_INFO("%s: connecting...", rc->name);
323 rc->n_attempted_connections++;
324 retval = vconn_open(rc->name, OFP_VERSION, &rc->vconn);
326 rc->backoff_deadline = time_now() + rc->backoff;
327 state_transition(rc, S_CONNECTING);
329 VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(retval));
330 rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
337 timeout_BACKOFF(const struct rconn *rc)
343 run_BACKOFF(struct rconn *rc)
351 timeout_CONNECTING(const struct rconn *rc)
353 return MAX(1, rc->backoff);
357 run_CONNECTING(struct rconn *rc)
359 int retval = vconn_connect(rc->vconn);
361 VLOG_INFO("%s: connected", rc->name);
362 rc->n_successful_connections++;
363 state_transition(rc, S_ACTIVE);
364 rc->last_connected = rc->state_entered;
365 } else if (retval != EAGAIN) {
366 VLOG_INFO("%s: connection failed (%s)", rc->name, strerror(retval));
367 disconnect(rc, retval);
368 } else if (timed_out(rc)) {
369 VLOG_INFO("%s: connection timed out", rc->name);
370 rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
376 do_tx_work(struct rconn *rc)
381 while (rc->txq.n > 0) {
382 int error = try_send(rc);
388 poll_immediate_wake();
393 timeout_ACTIVE(const struct rconn *rc)
395 if (rc->probe_interval) {
396 unsigned int base = MAX(rc->last_received, rc->state_entered);
397 unsigned int arg = base + rc->probe_interval - rc->state_entered;
404 run_ACTIVE(struct rconn *rc)
407 unsigned int base = MAX(rc->last_received, rc->state_entered);
408 VLOG_DBG("%s: idle %u seconds, sending inactivity probe",
409 rc->name, (unsigned int) (time_now() - base));
411 /* Ordering is important here: rconn_send() can transition to BACKOFF,
412 * and we don't want to transition back to IDLE if so, because then we
413 * can end up queuing a packet with vconn == NULL and then *boom*. */
414 state_transition(rc, S_IDLE);
415 rconn_send(rc, make_echo_request(), NULL);
423 timeout_IDLE(const struct rconn *rc)
425 return rc->probe_interval;
429 run_IDLE(struct rconn *rc)
432 question_connectivity(rc);
433 VLOG_ERR("%s: no response to inactivity probe after %u "
434 "seconds, disconnecting",
435 rc->name, elapsed_in_this_state(rc));
442 /* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
443 * disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
444 * connected, attempts to send packets in the send queue, if any. */
446 rconn_run(struct rconn *rc)
450 old_state = rc->state;
452 #define STATE(NAME, VALUE) case S_##NAME: run_##NAME(rc); break;
458 } while (rc->state != old_state);
461 /* Causes the next call to poll_block() to wake up when rconn_run() should be
464 rconn_run_wait(struct rconn *rc)
466 unsigned int timeo = timeout(rc);
467 if (timeo != UINT_MAX) {
468 unsigned int expires = sat_add(rc->state_entered, timeo);
469 unsigned int remaining = sat_sub(expires, time_now());
470 poll_timer_wait(sat_mul(remaining, 1000));
473 if ((rc->state & (S_ACTIVE | S_IDLE)) && rc->txq.n) {
474 vconn_wait(rc->vconn, WAIT_SEND);
478 /* Attempts to receive a packet from 'rc'. If successful, returns the packet;
479 * otherwise, returns a null pointer. The caller is responsible for freeing
480 * the packet (with ofpbuf_delete()). */
482 rconn_recv(struct rconn *rc)
484 if (rc->state & (S_ACTIVE | S_IDLE)) {
485 struct ofpbuf *buffer;
486 int error = vconn_recv(rc->vconn, &buffer);
488 copy_to_monitor(rc, buffer);
489 if (is_admitted_msg(buffer)
490 || time_now() - rc->last_connected >= 30) {
491 rc->probably_admitted = true;
492 rc->last_admitted = time_now();
494 rc->last_received = time_now();
495 rc->packets_received++;
496 if (rc->state == S_IDLE) {
497 state_transition(rc, S_ACTIVE);
500 } else if (error != EAGAIN) {
501 disconnect(rc, error);
507 /* Causes the next call to poll_block() to wake up when a packet may be ready
508 * to be received by vconn_recv() on 'rc'. */
510 rconn_recv_wait(struct rconn *rc)
513 vconn_wait(rc->vconn, WAIT_RECV);
517 /* Sends 'b' on 'rc'. Returns 0 if successful (in which case 'b' is
518 * destroyed), or ENOTCONN if 'rc' is not currently connected (in which case
519 * the caller retains ownership of 'b').
521 * If 'counter' is non-null, then 'counter' will be incremented while the
522 * packet is in flight, then decremented when it has been sent (or discarded
523 * due to disconnection). Because 'b' may be sent (or discarded) before this
524 * function returns, the caller may not be able to observe any change in
527 * There is no rconn_send_wait() function: an rconn has a send queue that it
528 * takes care of sending if you call rconn_run(), which will have the side
529 * effect of waking up poll_block(). */
531 rconn_send(struct rconn *rc, struct ofpbuf *b,
532 struct rconn_packet_counter *counter)
534 if (rconn_is_connected(rc)) {
535 COVERAGE_INC(rconn_queued);
536 copy_to_monitor(rc, b);
537 b->private = counter;
539 rconn_packet_counter_inc(counter);
541 queue_push_tail(&rc->txq, b);
543 /* If the queue was empty before we added 'b', try to send some
544 * packets. (But if the queue had packets in it, it's because the
545 * vconn is backlogged and there's no point in stuffing more into it
546 * now. We'll get back to that in rconn_run().) */
547 if (rc->txq.n == 1) {
556 /* Sends 'b' on 'rc'. Increments 'counter' while the packet is in flight; it
557 * will be decremented when it has been sent (or discarded due to
558 * disconnection). Returns 0 if successful, EAGAIN if 'counter->n' is already
559 * at least as large as 'queue_limit', or ENOTCONN if 'rc' is not currently
560 * connected. Regardless of return value, 'b' is destroyed.
562 * Because 'b' may be sent (or discarded) before this function returns, the
563 * caller may not be able to observe any change in 'counter'.
565 * There is no rconn_send_wait() function: an rconn has a send queue that it
566 * takes care of sending if you call rconn_run(), which will have the side
567 * effect of waking up poll_block(). */
569 rconn_send_with_limit(struct rconn *rc, struct ofpbuf *b,
570 struct rconn_packet_counter *counter, int queue_limit)
573 retval = counter->n >= queue_limit ? EAGAIN : rconn_send(rc, b, counter);
575 COVERAGE_INC(rconn_overflow);
581 /* Returns the total number of packets successfully sent on the underlying
582 * vconn. A packet is not counted as sent while it is still queued in the
583 * rconn, only when it has been successfuly passed to the vconn. */
585 rconn_packets_sent(const struct rconn *rc)
587 return rc->packets_sent;
590 /* Adds 'vconn' to 'rc' as a monitoring connection, to which all messages sent
591 * and received on 'rconn' will be copied. 'rc' takes ownership of 'vconn'. */
593 rconn_add_monitor(struct rconn *rc, struct vconn *vconn)
595 if (rc->n_monitors < ARRAY_SIZE(rc->monitors)) {
596 VLOG_INFO("new monitor connection from %s", vconn_get_name(vconn));
597 rc->monitors[rc->n_monitors++] = vconn;
599 VLOG_DBG("too many monitor connections, discarding %s",
600 vconn_get_name(vconn));
605 /* Returns 'rc''s name (the 'name' argument passed to rconn_new()). */
607 rconn_get_name(const struct rconn *rc)
612 /* Returns true if 'rconn' is connected or in the process of reconnecting,
613 * false if 'rconn' is disconnected and will not reconnect on its own. */
615 rconn_is_alive(const struct rconn *rconn)
617 return rconn->state != S_VOID;
620 /* Returns true if 'rconn' is connected, false otherwise. */
622 rconn_is_connected(const struct rconn *rconn)
624 return is_connected_state(rconn->state);
627 /* Returns 0 if 'rconn' is connected. Otherwise, if 'rconn' is in a "failure
628 * mode" (that is, it is not connected), returns the number of seconds that it
629 * has been in failure mode, ignoring any times that it connected but the
630 * controller's admission control policy caused it to be quickly
633 rconn_failure_duration(const struct rconn *rconn)
635 return rconn_is_connected(rconn) ? 0 : time_now() - rconn->last_admitted;
638 /* Returns the IP address of the peer, or 0 if the peer is not connected over
639 * an IP-based protocol or if its IP address is not known. */
641 rconn_get_remote_ip(const struct rconn *rconn)
643 return rconn->vconn ? vconn_get_remote_ip(rconn->vconn) : 0;
646 /* Returns the transport port of the peer, or 0 if the peer does not
647 * contain a port or if the port is not known. */
649 rconn_get_remote_port(const struct rconn *rconn)
651 return rconn->vconn ? vconn_get_remote_port(rconn->vconn) : 0;
654 /* Returns the IP address used to connect to the peer, or 0 if the
655 * connection is not an IP-based protocol or if its IP address is not
658 rconn_get_local_ip(const struct rconn *rconn)
660 return rconn->vconn ? vconn_get_local_ip(rconn->vconn) : 0;
663 /* Returns the transport port used to connect to the peer, or 0 if the
664 * connection does not contain a port or if the port is not known. */
666 rconn_get_local_port(const struct rconn *rconn)
668 return rconn->vconn ? vconn_get_local_port(rconn->vconn) : 0;
671 /* If 'rconn' can't connect to the peer, it could be for any number of reasons.
672 * Usually, one would assume it is because the peer is not running or because
673 * the network is partitioned. But it could also be because the network
674 * topology has changed, in which case the upper layer will need to reassess it
675 * (in particular, obtain a new IP address via DHCP and find the new location
676 * of the controller). When this appears that this might be the case, this
677 * function returns true. It also clears the questionability flag and prevents
678 * it from being set again for some time. */
680 rconn_is_connectivity_questionable(struct rconn *rconn)
682 bool questionable = rconn->questionable_connectivity;
683 rconn->questionable_connectivity = false;
687 /* Returns the total number of packets successfully received by the underlying
690 rconn_packets_received(const struct rconn *rc)
692 return rc->packets_received;
695 /* Returns a string representing the internal state of 'rc'. The caller must
696 * not modify or free the string. */
698 rconn_get_state(const struct rconn *rc)
700 return state_name(rc->state);
703 /* Returns the number of connection attempts made by 'rc', including any
704 * ongoing attempt that has not yet succeeded or failed. */
706 rconn_get_attempted_connections(const struct rconn *rc)
708 return rc->n_attempted_connections;
711 /* Returns the number of successful connection attempts made by 'rc'. */
713 rconn_get_successful_connections(const struct rconn *rc)
715 return rc->n_successful_connections;
718 /* Returns the time at which the last successful connection was made by
721 rconn_get_last_connection(const struct rconn *rc)
723 return rc->last_connected;
726 /* Returns the time at which the last OpenFlow message was received by 'rc'.
727 * If no packets have been received on 'rc', returns the time at which 'rc'
730 rconn_get_last_received(const struct rconn *rc)
732 return rc->last_received;
735 /* Returns the time at which 'rc' was created. */
737 rconn_get_creation_time(const struct rconn *rc)
739 return rc->creation_time;
742 /* Returns the approximate number of seconds that 'rc' has been connected. */
744 rconn_get_total_time_connected(const struct rconn *rc)
746 return (rc->total_time_connected
747 + (rconn_is_connected(rc) ? elapsed_in_this_state(rc) : 0));
750 /* Returns the current amount of backoff, in seconds. This is the amount of
751 * time after which the rconn will transition from BACKOFF to CONNECTING. */
753 rconn_get_backoff(const struct rconn *rc)
758 /* Returns the number of seconds spent in this state so far. */
760 rconn_get_state_elapsed(const struct rconn *rc)
762 return elapsed_in_this_state(rc);
765 /* Returns 'rc''s current connection sequence number, a number that changes
766 * every time that 'rconn' connects or disconnects. */
768 rconn_get_connection_seqno(const struct rconn *rc)
773 struct rconn_packet_counter *
774 rconn_packet_counter_create(void)
776 struct rconn_packet_counter *c = xmalloc(sizeof *c);
783 rconn_packet_counter_destroy(struct rconn_packet_counter *c)
786 assert(c->ref_cnt > 0);
787 if (!--c->ref_cnt && !c->n) {
794 rconn_packet_counter_inc(struct rconn_packet_counter *c)
800 rconn_packet_counter_dec(struct rconn_packet_counter *c)
803 if (!--c->n && !c->ref_cnt) {
808 /* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
809 * otherwise a positive errno value. */
811 try_send(struct rconn *rc)
814 struct ofpbuf *next = rc->txq.head->next;
815 struct rconn_packet_counter *counter = rc->txq.head->private;
816 retval = vconn_send(rc->vconn, rc->txq.head);
818 if (retval != EAGAIN) {
819 disconnect(rc, retval);
823 COVERAGE_INC(rconn_sent);
826 rconn_packet_counter_dec(counter);
828 queue_advance_head(&rc->txq, next);
832 /* Disconnects 'rc'. 'error' is used only for logging purposes. If it is
833 * nonzero, then it should be EOF to indicate the connection was closed by the
834 * peer in a normal fashion or a positive errno value. */
836 disconnect(struct rconn *rc, int error)
839 time_t now = time_now();
841 if (rc->state & (S_CONNECTING | S_ACTIVE | S_IDLE)) {
843 VLOG_WARN("%s: connection dropped (%s)",
844 rc->name, strerror(error));
845 } else if (error == EOF) {
847 VLOG_INFO("%s: connection closed by peer", rc->name);
850 VLOG_INFO("%s: connection dropped", rc->name);
852 vconn_close(rc->vconn);
857 if (now >= rc->backoff_deadline) {
860 rc->backoff = MIN(rc->max_backoff, MAX(1, 2 * rc->backoff));
861 VLOG_INFO("%s: waiting %d seconds before reconnect\n",
862 rc->name, rc->backoff);
864 rc->backoff_deadline = now + rc->backoff;
865 state_transition(rc, S_BACKOFF);
866 if (now - rc->last_connected > 60) {
867 question_connectivity(rc);
870 rconn_disconnect(rc);
874 /* Drops all the packets from 'rc''s send queue and decrements their queue
877 flush_queue(struct rconn *rc)
882 while (rc->txq.n > 0) {
883 struct ofpbuf *b = queue_pop_head(&rc->txq);
884 struct rconn_packet_counter *counter = b->private;
886 rconn_packet_counter_dec(counter);
888 COVERAGE_INC(rconn_discarded);
891 poll_immediate_wake();
895 elapsed_in_this_state(const struct rconn *rc)
897 return time_now() - rc->state_entered;
901 timeout(const struct rconn *rc)
904 #define STATE(NAME, VALUE) case S_##NAME: return timeout_##NAME(rc);
913 timed_out(const struct rconn *rc)
915 return time_now() >= sat_add(rc->state_entered, timeout(rc));
919 state_transition(struct rconn *rc, enum state state)
921 rc->seqno += (rc->state == S_ACTIVE) != (state == S_ACTIVE);
922 if (is_connected_state(state) && !is_connected_state(rc->state)) {
923 rc->probably_admitted = false;
925 if (rconn_is_connected(rc)) {
926 rc->total_time_connected += elapsed_in_this_state(rc);
928 VLOG_DBG("%s: entering %s", rc->name, state_name(state));
930 rc->state_entered = time_now();
934 question_connectivity(struct rconn *rc)
936 time_t now = time_now();
937 if (now - rc->last_questioned > 60) {
938 rc->questionable_connectivity = true;
939 rc->last_questioned = now;
944 copy_to_monitor(struct rconn *rc, const struct ofpbuf *b)
946 struct ofpbuf *clone = NULL;
950 for (i = 0; i < rc->n_monitors; ) {
951 struct vconn *vconn = rc->monitors[i];
954 clone = ofpbuf_clone(b);
956 retval = vconn_send(vconn, clone);
959 } else if (retval != EAGAIN) {
960 VLOG_DBG("%s: closing monitor connection to %s: %s",
961 rconn_get_name(rc), vconn_get_name(vconn),
963 rc->monitors[i] = rc->monitors[--rc->n_monitors];
968 ofpbuf_delete(clone);
972 is_connected_state(enum state state)
974 return (state & (S_ACTIVE | S_IDLE)) != 0;
978 is_admitted_msg(const struct ofpbuf *b)
980 struct ofp_header *oh = b->data;
981 uint8_t type = oh->type;
983 && (1u << type) & ((1u << OFPT_HELLO) |
985 (1u << OFPT_ECHO_REQUEST) |
986 (1u << OFPT_ECHO_REPLY) |
987 (1u << OFPT_VENDOR) |
988 (1u << OFPT_FEATURES_REQUEST) |
989 (1u << OFPT_FEATURES_REPLY) |
990 (1u << OFPT_GET_CONFIG_REQUEST) |
991 (1u << OFPT_GET_CONFIG_REPLY) |
992 (1u << OFPT_SET_CONFIG)));