1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
5 * (Software) available for public use and benefit with the expectation
6 * that others will use, modify and enhance the Software and contribute
7 * those enhancements back to the community. However, since we would
8 * like to make the Software available for broadest use, with as few
9 * restrictions as possible permission is hereby granted, free of
10 * charge, to any person obtaining a copy of this Software to deal in
11 * the Software under the copyrights without restriction, including
12 * without limitation the rights to use, copy, modify, merge, publish,
13 * distribute, sublicense, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
17 * The above copyright notice and this permission notice shall be
18 * included in all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
25 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
26 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 * The name and trademarks of copyright holder(s) may NOT be used in
30 * advertising or publicity pertaining to the Software or any
31 * derivatives without specific, written prior permission.
40 #include "poll-loop.h"
41 #include "ofp-print.h"
45 #define THIS_MODULE VLM_rconn
48 /* A reliable connection to an OpenFlow switch or controller.
50 * See the large comment in rconn.h for more information. */
58 time_t backoff_deadline;
60 time_t last_connected;
61 unsigned int packets_sent;
63 /* Throughout this file, "probe" is shorthand for "inactivity probe".
64 * When nothing has been received from the peer for a while, we send out
65 * an echo request as an inactivity probe packet. We should receive back
67 int probe_interval; /* Secs of inactivity before sending probe. */
68 time_t probe_sent; /* Time at which last probe sent, or 0 if none
69 * has been sent since 'last_connected'. */
72 static struct rconn *create_rconn(const char *name, int txq_limit,
73 int probe_interval, struct vconn *);
74 static int try_send(struct rconn *);
75 static void disconnect(struct rconn *, int error);
76 static time_t probe_deadline(const struct rconn *);
78 /* Creates and returns a new rconn that connects (and re-connects as necessary)
79 * to the vconn named 'name'.
81 * 'txq_limit' is the maximum length of the send queue, in packets.
83 * 'probe_interval' is a number of seconds. If the interval passes once
84 * without an OpenFlow message being received from the peer, the rconn sends
85 * out an "echo request" message. If the interval passes again without a
86 * message being received, the rconn disconnects and re-connects to the peer.
87 * Setting 'probe_interval' to 0 disables this behavior. */
89 rconn_new(const char *name, int txq_limit, int probe_interval)
91 return create_rconn(name, txq_limit, probe_interval, NULL);
94 /* Creates and returns a new rconn that is initially connected to 'vconn' and
95 * has the given 'name'. The rconn will not re-connect after the connection
98 * 'txq_limit' is the maximum length of the send queue, in packets. */
100 rconn_new_from_vconn(const char *name, int txq_limit, struct vconn *vconn)
102 assert(vconn != NULL);
103 return create_rconn(name, txq_limit, 0, vconn);
106 /* Disconnects 'rc' and frees the underlying storage. */
108 rconn_destroy(struct rconn *rc)
112 vconn_close(rc->vconn);
113 queue_destroy(&rc->txq);
118 /* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
119 * disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
120 * connected, attempts to send packets in the send queue, if any. */
122 rconn_run(struct rconn *rc)
125 if (rc->reliable && time(0) >= rc->backoff_deadline) {
128 retval = vconn_open(rc->name, &rc->vconn);
130 rc->backoff_deadline = time(0) + rc->backoff;
131 rc->connected = false;
133 VLOG_WARN("%s: connection failed (%s)",
134 rc->name, strerror(retval));
138 } else if (!rc->connected) {
139 int error = vconn_connect(rc->vconn);
141 VLOG_WARN("%s: connected", rc->name);
142 if (vconn_is_passive(rc->vconn)) {
143 fatal(0, "%s: passive vconn not supported in switch",
146 rc->connected = true;
147 } else if (error != EAGAIN) {
148 VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(error));
152 if (rc->probe_interval) {
153 time_t now = time(0);
154 if (now >= probe_deadline(rc)) {
155 if (!rc->probe_sent) {
156 queue_push_tail(&rc->txq, make_echo_request());
157 rc->probe_sent = now;
158 VLOG_DBG("%s: idle %d seconds, sending inactivity probe",
159 rc->name, (int) (now - rc->last_connected));
161 VLOG_ERR("%s: no response to inactivity probe after %d "
162 "seconds, disconnecting",
163 rc->name, (int) (now - rc->probe_sent));
168 while (rc->txq.n > 0) {
169 int error = try_send(rc);
170 if (error == EAGAIN) {
173 disconnect(rc, error);
180 /* Causes the next call to poll_block() to wake up when rconn_run() should be
183 rconn_run_wait(struct rconn *rc)
187 vconn_wait(rc->vconn, WAIT_SEND);
189 if (rc->probe_interval) {
190 poll_timer_wait((probe_deadline(rc) - time(0)) * 1000);
193 poll_timer_wait((rc->backoff_deadline - time(0)) * 1000);
197 /* Returns the time at which, should nothing be received, we should send out an
198 * inactivity probe (if none has yet been sent) or conclude that the connection
199 * is dead (if a probe has already been sent). */
201 probe_deadline(const struct rconn *rc)
203 assert(rc->probe_interval);
204 return (rc->probe_interval
205 + (rc->probe_sent ? rc->probe_sent : rc->last_connected));
208 /* Attempts to receive a packet from 'rc'. If successful, returns the packet;
209 * otherwise, returns a null pointer. The caller is responsible for freeing
210 * the packet (with buffer_delete()). */
212 rconn_recv(struct rconn *rc)
214 if (rc->vconn && rc->connected) {
215 struct buffer *buffer;
216 int error = vconn_recv(rc->vconn, &buffer);
218 rc->last_connected = time(0);
221 } else if (error != EAGAIN) {
222 disconnect(rc, error);
228 /* Causes the next call to poll_block() to wake up when a packet may be ready
229 * to be received by vconn_recv() on 'rc'. */
231 rconn_recv_wait(struct rconn *rc)
234 vconn_wait(rc->vconn, WAIT_RECV);
238 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if at least 'txq_limit'
239 * packets are already queued, otherwise a positive errno value. */
241 do_send(struct rconn *rc, struct buffer *b, int txq_limit)
244 if (rc->txq.n < txq_limit) {
245 queue_push_tail(&rc->txq, b);
246 if (rc->txq.n == 1) {
258 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
259 * full, or ENOTCONN if 'rc' is not currently connected.
261 * There is no rconn_send_wait() function: an rconn has a send queue that it
262 * takes care of sending if you call rconn_wait(), which will have the side
263 * effect of waking up poll_block(). */
265 rconn_send(struct rconn *rc, struct buffer *b)
267 return do_send(rc, b, rc->txq_limit);
270 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
271 * full, otherwise a positive errno value.
273 * Compared to rconn_send(), this function relaxes the queue limit, allowing
274 * more packets than usual to be queued. */
276 rconn_force_send(struct rconn *rc, struct buffer *b)
278 return do_send(rc, b, 2 * rc->txq_limit);
281 /* Returns true if 'rc''s send buffer is full,
282 * false if it has room for at least one more packet. */
284 rconn_is_full(const struct rconn *rc)
286 return rc->txq.n >= rc->txq_limit;
289 /* Returns the total number of packets successfully sent on the underlying
290 * vconn. A packet is not counted as sent while it is still queued in the
291 * rconn, only when it has been successfuly passed to the vconn. */
293 rconn_packets_sent(const struct rconn *rc)
295 return rc->packets_sent;
298 /* Returns 'rc''s name (the 'name' argument passed to rconn_new()). */
300 rconn_get_name(const struct rconn *rc)
305 /* Returns true if 'rconn' is connected or in the process of reconnecting,
306 * false if 'rconn' is disconnected and will not be reconnected. */
308 rconn_is_alive(const struct rconn *rconn)
310 return rconn->reliable || rconn->vconn;
313 /* Returns true if 'rconn' is connected, false otherwise. */
315 rconn_is_connected(const struct rconn *rconn)
317 return rconn->vconn && !vconn_connect(rconn->vconn);
320 /* Returns 0 if 'rconn' is connected, otherwise the number of seconds that it
321 * has been disconnected. */
323 rconn_disconnected_duration(const struct rconn *rconn)
325 return rconn_is_connected(rconn) ? 0 : time(0) - rconn->last_connected;
328 static struct rconn *
329 create_rconn(const char *name, int txq_limit, int probe_interval,
332 struct rconn *rc = xmalloc(sizeof *rc);
333 assert(txq_limit > 0);
334 rc->reliable = vconn == NULL;
335 rc->connected = vconn != NULL;
336 rc->name = xstrdup(name);
338 queue_init(&rc->txq);
339 rc->txq_limit = txq_limit;
340 rc->backoff_deadline = 0;
342 rc->last_connected = time(0);
343 rc->probe_interval = (probe_interval
344 ? MAX(5, probe_interval) : 0);
346 rc->packets_sent = 0;
350 /* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
351 * otherwise a positive errno value. */
353 try_send(struct rconn *rc)
356 struct buffer *next = rc->txq.head->next;
357 retval = vconn_send(rc->vconn, rc->txq.head);
362 queue_advance_head(&rc->txq, next);
366 /* Disconnects 'rc'. 'error' is used only for logging purposes. If it is
367 * nonzero, then it should be EOF to indicate the connection was closed by the
368 * peer in a normal fashion or a positive errno value. */
370 disconnect(struct rconn *rc, int error)
372 time_t now = time(0);
376 VLOG_WARN("%s: connection dropped (%s)",
377 rc->name, strerror(error));
378 } else if (error == EOF) {
380 VLOG_WARN("%s: connection closed", rc->name);
383 VLOG_WARN("%s: connection dropped", rc->name);
385 vconn_close(rc->vconn);
387 queue_clear(&rc->txq);
390 if (now >= rc->backoff_deadline) {
393 rc->backoff = MIN(60, MAX(1, 2 * rc->backoff));
394 VLOG_WARN("%s: waiting %d seconds before reconnect\n",
395 rc->name, rc->backoff);
397 rc->backoff_deadline = now + rc->backoff;