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;
61 time_t last_connected;
62 unsigned int packets_sent;
64 /* Throughout this file, "probe" is shorthand for "inactivity probe".
65 * When nothing has been received from the peer for a while, we send out
66 * an echo request as an inactivity probe packet. We should receive back
68 int probe_interval; /* Secs of inactivity before sending probe. */
69 time_t probe_sent; /* Time at which last probe sent, or 0 if none
70 * has been sent since 'last_connected'. */
73 static struct rconn *create_rconn(const char *name, int txq_limit,
74 int probe_interval, int max_backoff,
76 static int try_send(struct rconn *);
77 static void disconnect(struct rconn *, int error);
78 static time_t probe_deadline(const struct rconn *);
80 /* Creates and returns a new rconn that connects (and re-connects as necessary)
81 * to the vconn named 'name'.
83 * 'txq_limit' is the maximum length of the send queue, in packets.
85 * 'probe_interval' is a number of seconds. If the interval passes once
86 * without an OpenFlow message being received from the peer, the rconn sends
87 * out an "echo request" message. If the interval passes again without a
88 * message being received, the rconn disconnects and re-connects to the peer.
89 * Setting 'probe_interval' to 0 disables this behavior.
91 * 'max_backoff' is the maximum number of seconds between attempts to connect
92 * to the peer. The actual interval starts at 1 second and doubles on each
93 * failure until it reaches 'max_backoff'. If 0 is specified, the default of
94 * 60 seconds is used. */
96 rconn_new(const char *name, int txq_limit, int probe_interval, int max_backoff)
98 return create_rconn(name, txq_limit, probe_interval, max_backoff, NULL);
101 /* Creates and returns a new rconn that is initially connected to 'vconn' and
102 * has the given 'name'. The rconn will not re-connect after the connection
105 * 'txq_limit' is the maximum length of the send queue, in packets. */
107 rconn_new_from_vconn(const char *name, int txq_limit, struct vconn *vconn)
109 assert(vconn != NULL);
110 return create_rconn(name, txq_limit, 0, 0, vconn);
113 /* Disconnects 'rc' and frees the underlying storage. */
115 rconn_destroy(struct rconn *rc)
119 vconn_close(rc->vconn);
120 queue_destroy(&rc->txq);
125 /* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
126 * disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
127 * connected, attempts to send packets in the send queue, if any. */
129 rconn_run(struct rconn *rc)
132 if (rc->reliable && time(0) >= rc->backoff_deadline) {
135 retval = vconn_open(rc->name, &rc->vconn);
137 rc->backoff_deadline = time(0) + rc->backoff;
138 rc->connected = false;
140 VLOG_WARN("%s: connection failed (%s)",
141 rc->name, strerror(retval));
145 } else if (!rc->connected) {
146 int error = vconn_connect(rc->vconn);
148 VLOG_WARN("%s: connected", rc->name);
149 if (vconn_is_passive(rc->vconn)) {
150 fatal(0, "%s: passive vconn not supported in switch",
153 rc->connected = true;
154 } else if (error != EAGAIN) {
155 VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(error));
159 if (rc->probe_interval) {
160 time_t now = time(0);
161 if (now >= probe_deadline(rc)) {
162 if (!rc->probe_sent) {
163 queue_push_tail(&rc->txq, make_echo_request());
164 rc->probe_sent = now;
165 VLOG_DBG("%s: idle %d seconds, sending inactivity probe",
166 rc->name, (int) (now - rc->last_connected));
168 VLOG_ERR("%s: no response to inactivity probe after %d "
169 "seconds, disconnecting",
170 rc->name, (int) (now - rc->probe_sent));
175 while (rc->txq.n > 0) {
176 int error = try_send(rc);
177 if (error == EAGAIN) {
180 disconnect(rc, error);
187 /* Causes the next call to poll_block() to wake up when rconn_run() should be
190 rconn_run_wait(struct rconn *rc)
194 vconn_wait(rc->vconn, WAIT_SEND);
196 if (rc->probe_interval) {
197 poll_timer_wait((probe_deadline(rc) - time(0)) * 1000);
200 poll_timer_wait((rc->backoff_deadline - time(0)) * 1000);
204 /* Returns the time at which, should nothing be received, we should send out an
205 * inactivity probe (if none has yet been sent) or conclude that the connection
206 * is dead (if a probe has already been sent). */
208 probe_deadline(const struct rconn *rc)
210 assert(rc->probe_interval);
211 return (rc->probe_interval
212 + (rc->probe_sent ? rc->probe_sent : rc->last_connected));
215 /* Attempts to receive a packet from 'rc'. If successful, returns the packet;
216 * otherwise, returns a null pointer. The caller is responsible for freeing
217 * the packet (with buffer_delete()). */
219 rconn_recv(struct rconn *rc)
221 if (rc->vconn && rc->connected) {
222 struct buffer *buffer;
223 int error = vconn_recv(rc->vconn, &buffer);
225 rc->last_connected = time(0);
228 } else if (error != EAGAIN) {
229 disconnect(rc, error);
235 /* Causes the next call to poll_block() to wake up when a packet may be ready
236 * to be received by vconn_recv() on 'rc'. */
238 rconn_recv_wait(struct rconn *rc)
241 vconn_wait(rc->vconn, WAIT_RECV);
245 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if at least 'txq_limit'
246 * packets are already queued, otherwise a positive errno value. */
248 do_send(struct rconn *rc, struct buffer *b, int txq_limit)
251 if (rc->txq.n < txq_limit) {
252 queue_push_tail(&rc->txq, b);
253 if (rc->txq.n == 1) {
265 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
266 * full, or ENOTCONN if 'rc' is not currently connected.
268 * There is no rconn_send_wait() function: an rconn has a send queue that it
269 * takes care of sending if you call rconn_run(), which will have the side
270 * effect of waking up poll_block(). */
272 rconn_send(struct rconn *rc, struct buffer *b)
274 return do_send(rc, b, rc->txq_limit);
277 /* Sends 'b' on 'rc'. Returns 0 if successful, EAGAIN if the send queue is
278 * full, otherwise a positive errno value.
280 * Compared to rconn_send(), this function relaxes the queue limit, allowing
281 * more packets than usual to be queued. */
283 rconn_force_send(struct rconn *rc, struct buffer *b)
285 return do_send(rc, b, 2 * rc->txq_limit);
288 /* Returns true if 'rc''s send buffer is full,
289 * false if it has room for at least one more packet. */
291 rconn_is_full(const struct rconn *rc)
293 return rc->txq.n >= rc->txq_limit;
296 /* Returns the total number of packets successfully sent on the underlying
297 * vconn. A packet is not counted as sent while it is still queued in the
298 * rconn, only when it has been successfuly passed to the vconn. */
300 rconn_packets_sent(const struct rconn *rc)
302 return rc->packets_sent;
305 /* Returns 'rc''s name (the 'name' argument passed to rconn_new()). */
307 rconn_get_name(const struct rconn *rc)
312 /* Returns true if 'rconn' is connected or in the process of reconnecting,
313 * false if 'rconn' is disconnected and will not be reconnected. */
315 rconn_is_alive(const struct rconn *rconn)
317 return rconn->reliable || rconn->vconn;
320 /* Returns true if 'rconn' is connected, false otherwise. */
322 rconn_is_connected(const struct rconn *rconn)
324 return rconn->vconn && !vconn_connect(rconn->vconn);
327 /* Returns 0 if 'rconn' is connected, otherwise the number of seconds that it
328 * has been disconnected. */
330 rconn_disconnected_duration(const struct rconn *rconn)
332 return rconn_is_connected(rconn) ? 0 : time(0) - rconn->last_connected;
335 /* Returns the IP address of the peer, or 0 if the peer is not connected over
336 * an IP-based protocol or if its IP address is not known. */
338 rconn_get_ip(const struct rconn *rconn)
340 return rconn->vconn ? vconn_get_ip(rconn->vconn) : 0;
343 static struct rconn *
344 create_rconn(const char *name, int txq_limit, int probe_interval,
345 int max_backoff, struct vconn *vconn)
347 struct rconn *rc = xmalloc(sizeof *rc);
348 assert(txq_limit > 0);
349 rc->reliable = vconn == NULL;
350 rc->connected = vconn != NULL;
351 rc->name = xstrdup(name);
353 queue_init(&rc->txq);
354 rc->txq_limit = txq_limit;
355 rc->backoff_deadline = time(0);
357 rc->max_backoff = max_backoff ? max_backoff : 60;
358 rc->last_connected = time(0);
359 rc->probe_interval = (probe_interval
360 ? MAX(5, probe_interval) : 0);
362 rc->packets_sent = 0;
366 /* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
367 * otherwise a positive errno value. */
369 try_send(struct rconn *rc)
372 struct buffer *next = rc->txq.head->next;
373 retval = vconn_send(rc->vconn, rc->txq.head);
378 queue_advance_head(&rc->txq, next);
382 /* Disconnects 'rc'. 'error' is used only for logging purposes. If it is
383 * nonzero, then it should be EOF to indicate the connection was closed by the
384 * peer in a normal fashion or a positive errno value. */
386 disconnect(struct rconn *rc, int error)
388 time_t now = time(0);
392 VLOG_WARN("%s: connection dropped (%s)",
393 rc->name, strerror(error));
394 } else if (error == EOF) {
396 VLOG_WARN("%s: connection closed", rc->name);
399 VLOG_WARN("%s: connection dropped", rc->name);
401 vconn_close(rc->vconn);
403 queue_clear(&rc->txq);
406 if (now >= rc->backoff_deadline) {
409 rc->backoff = MIN(rc->max_backoff, MAX(1, 2 * rc->backoff));
410 VLOG_WARN("%s: waiting %d seconds before reconnect\n",
411 rc->name, rc->backoff);
413 rc->backoff_deadline = now + rc->backoff;