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
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9 * restrictions as possible permission is hereby granted, free of
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11 * the Software under the copyrights without restriction, including
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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
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29 * The name and trademarks of copyright holder(s) may NOT be used in
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31 * derivatives without specific, written prior permission.
40 #include "poll-loop.h"
41 #include "ofp-print.h"
46 #define THIS_MODULE VLM_rconn
49 /* A reliable connection to an OpenFlow switch or controller.
51 * See the large comment in rconn.h for more information. */
59 time_t backoff_deadline;
62 time_t last_connected;
63 unsigned int packets_sent;
65 /* Throughout this file, "probe" is shorthand for "inactivity probe".
66 * When nothing has been received from the peer for a while, we send out
67 * an echo request as an inactivity probe packet. We should receive back
69 int probe_interval; /* Secs of inactivity before sending probe. */
70 time_t probe_sent; /* Time at which last probe sent, or 0 if none
71 * has been sent since 'last_connected'. */
74 static struct rconn *create_rconn(const char *name, int txq_limit,
75 int probe_interval, int max_backoff,
77 static int try_send(struct rconn *);
78 static void disconnect(struct rconn *, int error);
79 static time_t probe_deadline(const struct rconn *);
81 /* Creates and returns a new rconn that connects (and re-connects as necessary)
82 * to the vconn named 'name'.
84 * 'txq_limit' is the maximum length of the send queue, in packets.
86 * 'probe_interval' is a number of seconds. If the interval passes once
87 * without an OpenFlow message being received from the peer, the rconn sends
88 * out an "echo request" message. If the interval passes again without a
89 * message being received, the rconn disconnects and re-connects to the peer.
90 * Setting 'probe_interval' to 0 disables this behavior.
92 * 'max_backoff' is the maximum number of seconds between attempts to connect
93 * to the peer. The actual interval starts at 1 second and doubles on each
94 * failure until it reaches 'max_backoff'. If 0 is specified, the default of
95 * 60 seconds is used. */
97 rconn_new(const char *name, int txq_limit, int probe_interval, int max_backoff)
99 return create_rconn(name, txq_limit, probe_interval, max_backoff, NULL);
102 /* Creates and returns a new rconn that is initially connected to 'vconn' and
103 * has the given 'name'. The rconn will not re-connect after the connection
106 * 'txq_limit' is the maximum length of the send queue, in packets. */
108 rconn_new_from_vconn(const char *name, int txq_limit, struct vconn *vconn)
110 assert(vconn != NULL);
111 return create_rconn(name, txq_limit, 0, 0, vconn);
114 /* Disconnects 'rc' and frees the underlying storage. */
116 rconn_destroy(struct rconn *rc)
120 vconn_close(rc->vconn);
121 queue_destroy(&rc->txq);
126 /* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
127 * disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
128 * connected, attempts to send packets in the send queue, if any. */
130 rconn_run(struct rconn *rc)
133 if (rc->reliable && time(0) >= rc->backoff_deadline) {
136 VLOG_WARN("%s: connecting...", rc->name);
137 retval = vconn_open(rc->name, &rc->vconn);
139 rc->backoff_deadline = time(0) + rc->backoff;
140 rc->connected = false;
142 VLOG_WARN("%s: connection failed (%s)",
143 rc->name, strerror(retval));
147 } else if (!rc->connected) {
148 int error = vconn_connect(rc->vconn);
150 VLOG_WARN("%s: connected", rc->name);
151 if (vconn_is_passive(rc->vconn)) {
152 fatal(0, "%s: passive vconn not supported in switch",
155 rc->connected = true;
156 } else if (error != EAGAIN) {
157 VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(error));
159 } else if (time(0) >= rc->backoff_deadline) {
160 VLOG_WARN("%s: connection timed out", rc->name);
161 rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
165 if (rc->probe_interval) {
166 time_t now = time(0);
167 if (now >= probe_deadline(rc)) {
168 if (!rc->probe_sent) {
169 queue_push_tail(&rc->txq, make_echo_request());
170 rc->probe_sent = now;
171 VLOG_DBG("%s: idle %d seconds, sending inactivity probe",
172 rc->name, (int) (now - rc->last_connected));
174 VLOG_ERR("%s: no response to inactivity probe after %d "
175 "seconds, disconnecting",
176 rc->name, (int) (now - rc->probe_sent));
181 while (rc->txq.n > 0) {
182 int error = try_send(rc);
183 if (error == EAGAIN) {
186 disconnect(rc, error);
193 /* Causes the next call to poll_block() to wake up when rconn_run() should be
196 rconn_run_wait(struct rconn *rc)
200 vconn_wait(rc->vconn, WAIT_SEND);
202 if (rc->probe_interval) {
203 poll_timer_wait((probe_deadline(rc) - time(0)) * 1000);
206 poll_timer_wait((rc->backoff_deadline - time(0)) * 1000);
210 /* Returns the time at which, should nothing be received, we should send out an
211 * inactivity probe (if none has yet been sent) or conclude that the connection
212 * is dead (if a probe has already been sent). */
214 probe_deadline(const struct rconn *rc)
216 assert(rc->probe_interval);
217 return (rc->probe_interval
218 + (rc->probe_sent ? rc->probe_sent : rc->last_connected));
221 /* Attempts to receive a packet from 'rc'. If successful, returns the packet;
222 * otherwise, returns a null pointer. The caller is responsible for freeing
223 * the packet (with buffer_delete()). */
225 rconn_recv(struct rconn *rc)
227 if (rc->vconn && rc->connected) {
228 struct buffer *buffer;
229 int error = vconn_recv(rc->vconn, &buffer);
231 rc->last_connected = time(0);
234 } else if (error != EAGAIN) {
235 disconnect(rc, error);
241 /* Causes the next call to poll_block() to wake up when a packet may be ready
242 * to be received by vconn_recv() on 'rc'. */
244 rconn_recv_wait(struct rconn *rc)
247 vconn_wait(rc->vconn, WAIT_RECV);
251 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if at least 'txq_limit'
252 * packets are already queued, otherwise a positive errno value. */
254 do_send(struct rconn *rc, struct buffer *b, int txq_limit)
257 if (rc->txq.n < txq_limit) {
258 queue_push_tail(&rc->txq, b);
259 if (rc->txq.n == 1) {
271 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
272 * full, or ENOTCONN if 'rc' is not currently connected.
274 * There is no rconn_send_wait() function: an rconn has a send queue that it
275 * takes care of sending if you call rconn_run(), which will have the side
276 * effect of waking up poll_block(). */
278 rconn_send(struct rconn *rc, struct buffer *b)
280 return do_send(rc, b, rc->txq_limit);
283 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
284 * full, otherwise a positive errno value.
286 * Compared to rconn_send(), this function relaxes the queue limit, allowing
287 * more packets than usual to be queued. */
289 rconn_force_send(struct rconn *rc, struct buffer *b)
291 return do_send(rc, b, 2 * rc->txq_limit);
294 /* Returns true if 'rc''s send buffer is full,
295 * false if it has room for at least one more packet. */
297 rconn_is_full(const struct rconn *rc)
299 return rc->txq.n >= rc->txq_limit;
302 /* Returns the total number of packets successfully sent on the underlying
303 * vconn. A packet is not counted as sent while it is still queued in the
304 * rconn, only when it has been successfuly passed to the vconn. */
306 rconn_packets_sent(const struct rconn *rc)
308 return rc->packets_sent;
311 /* Returns 'rc''s name (the 'name' argument passed to rconn_new()). */
313 rconn_get_name(const struct rconn *rc)
318 /* Returns true if 'rconn' is connected or in the process of reconnecting,
319 * false if 'rconn' is disconnected and will not be reconnected. */
321 rconn_is_alive(const struct rconn *rconn)
323 return rconn->reliable || rconn->vconn;
326 /* Returns true if 'rconn' is connected, false otherwise. */
328 rconn_is_connected(const struct rconn *rconn)
330 return rconn->vconn && !vconn_connect(rconn->vconn);
333 /* Returns 0 if 'rconn' is connected, otherwise the number of seconds that it
334 * has been disconnected. */
336 rconn_disconnected_duration(const struct rconn *rconn)
338 return rconn_is_connected(rconn) ? 0 : time(0) - rconn->last_connected;
341 /* Returns the IP address of the peer, or 0 if the peer is not connected over
342 * an IP-based protocol or if its IP address is not known. */
344 rconn_get_ip(const struct rconn *rconn)
346 return rconn->vconn ? vconn_get_ip(rconn->vconn) : 0;
349 static struct rconn *
350 create_rconn(const char *name, int txq_limit, int probe_interval,
351 int max_backoff, struct vconn *vconn)
353 struct rconn *rc = xmalloc(sizeof *rc);
354 assert(txq_limit > 0);
355 rc->reliable = vconn == NULL;
356 rc->connected = vconn != NULL;
357 rc->name = xstrdup(name);
359 queue_init(&rc->txq);
360 rc->txq_limit = txq_limit;
361 rc->backoff_deadline = time(0);
363 rc->max_backoff = max_backoff ? max_backoff : 60;
364 rc->last_connected = time(0);
365 rc->probe_interval = (probe_interval
366 ? MAX(5, probe_interval) : 0);
368 rc->packets_sent = 0;
372 /* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
373 * otherwise a positive errno value. */
375 try_send(struct rconn *rc)
378 struct buffer *next = rc->txq.head->next;
379 retval = vconn_send(rc->vconn, rc->txq.head);
384 queue_advance_head(&rc->txq, next);
388 /* Disconnects 'rc'. 'error' is used only for logging purposes. If it is
389 * nonzero, then it should be EOF to indicate the connection was closed by the
390 * peer in a normal fashion or a positive errno value. */
392 disconnect(struct rconn *rc, int error)
394 time_t now = time(0);
398 VLOG_WARN("%s: connection dropped (%s)",
399 rc->name, strerror(error));
400 } else if (error == EOF) {
402 VLOG_WARN("%s: connection closed", rc->name);
405 VLOG_WARN("%s: connection dropped", rc->name);
407 vconn_close(rc->vconn);
409 queue_clear(&rc->txq);
412 if (now >= rc->backoff_deadline) {
415 rc->backoff = MIN(rc->max_backoff, MAX(1, 2 * rc->backoff));
416 VLOG_WARN("%s: waiting %d seconds before reconnect\n",
417 rc->name, rc->backoff);
419 rc->backoff_deadline = now + rc->backoff;