/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
* Junior University
- *
+ *
* We are making the OpenFlow specification and associated documentation
* (Software) available for public use and benefit with the expectation
* that others will use, modify and enhance the Software and contribute
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
- *
+ *
* The name and trademarks of copyright holder(s) may NOT be used in
* advertising or publicity pertaining to the Software or any
* derivatives without specific, written prior permission.
#include "rconn.h"
#include <assert.h>
#include <errno.h>
+#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "buffer.h"
#define THIS_MODULE VLM_rconn
#include "vlog.h"
+#define STATES \
+ STATE(VOID, 1 << 0) \
+ STATE(BACKOFF, 1 << 1) \
+ STATE(CONNECTING, 1 << 2) \
+ STATE(ACTIVE, 1 << 3) \
+ STATE(IDLE, 1 << 4)
+enum state {
+#define STATE(NAME, VALUE) S_##NAME = VALUE,
+ STATES
+#undef STATE
+};
+
+static const char *
+state_name(enum state state)
+{
+ switch (state) {
+#define STATE(NAME, VALUE) case S_##NAME: return #NAME;
+ STATES
+#undef STATE
+ }
+ return "***ERROR***";
+}
+
/* A reliable connection to an OpenFlow switch or controller.
*
* See the large comment in rconn.h for more information. */
struct rconn {
- bool reliable;
- char *name;
+ enum state state;
+ time_t state_entered;
+ unsigned int min_timeout;
+
struct vconn *vconn;
- bool connected;
+ char *name;
+ bool reliable;
+
struct queue txq;
int txq_limit;
- time_t backoff_deadline;
+
int backoff;
int max_backoff;
+ time_t backoff_deadline;
+ time_t last_received;
time_t last_connected;
+
unsigned int packets_sent;
/* Throughout this file, "probe" is shorthand for "inactivity probe".
* an echo request as an inactivity probe packet. We should receive back
* a response. */
int probe_interval; /* Secs of inactivity before sending probe. */
- time_t probe_sent; /* Time at which last probe sent, or 0 if none
- * has been sent since 'last_connected'. */
};
-static struct rconn *create_rconn(const char *name, int txq_limit,
- int probe_interval, int max_backoff,
- struct vconn *);
+static unsigned int sat_add(unsigned int x, unsigned int y);
+static unsigned int sat_mul(unsigned int x, unsigned int y);
+static unsigned int elapsed_in_this_state(const struct rconn *);
+static bool timeout(struct rconn *, unsigned int secs);
+static void state_transition(struct rconn *, enum state);
static int try_send(struct rconn *);
+static void reconnect(struct rconn *);
static void disconnect(struct rconn *, int error);
-static time_t probe_deadline(const struct rconn *);
-/* Creates and returns a new rconn that connects (and re-connects as necessary)
- * to the vconn named 'name'.
+/* Creates a new rconn, connects it (reliably) to 'name', and returns it. */
+struct rconn *
+rconn_new(const char *name, int txq_limit, int inactivity_probe_interval,
+ int max_backoff)
+{
+ struct rconn *rc = rconn_create(txq_limit, inactivity_probe_interval,
+ max_backoff);
+ rconn_connect(rc, name);
+ return rc;
+}
+
+/* Creates a new rconn, connects it (unreliably) to 'vconn', and returns it. */
+struct rconn *
+rconn_new_from_vconn(const char *name, int txq_limit, struct vconn *vconn)
+{
+ struct rconn *rc = rconn_create(txq_limit, 60, 0);
+ rconn_connect_unreliably(rc, name, vconn);
+ return rc;
+}
+
+/* Creates and returns a new rconn.
*
* 'txq_limit' is the maximum length of the send queue, in packets.
*
* failure until it reaches 'max_backoff'. If 0 is specified, the default of
* 60 seconds is used. */
struct rconn *
-rconn_new(const char *name, int txq_limit, int probe_interval, int max_backoff)
+rconn_create(int txq_limit, int probe_interval, int max_backoff)
{
- return create_rconn(name, txq_limit, probe_interval, max_backoff, NULL);
+ struct rconn *rc = xcalloc(1, sizeof *rc);
+
+ rc->state = S_VOID;
+ rc->state_entered = time(0);
+ rc->min_timeout = 0;
+
+ rc->vconn = NULL;
+ rc->name = xstrdup("void");
+ rc->reliable = false;
+
+ queue_init(&rc->txq);
+ assert(txq_limit > 0);
+ rc->txq_limit = txq_limit;
+
+ rc->backoff = 0;
+ rc->max_backoff = max_backoff ? max_backoff : 60;
+ rc->backoff_deadline = TIME_MIN;
+ rc->last_received = time(0);
+ rc->last_connected = time(0);
+
+ rc->packets_sent = 0;
+
+ rc->probe_interval = probe_interval ? MAX(5, probe_interval) : 0;
+
+ return rc;
}
-/* Creates and returns a new rconn that is initially connected to 'vconn' and
- * has the given 'name'. The rconn will not re-connect after the connection
- * drops.
- *
- * 'txq_limit' is the maximum length of the send queue, in packets. */
-struct rconn *
-rconn_new_from_vconn(const char *name, int txq_limit, struct vconn *vconn)
+void
+rconn_connect(struct rconn *rc, const char *name)
+{
+ rconn_disconnect(rc);
+ free(rc->name);
+ rc->name = xstrdup(name);
+ rc->reliable = true;
+ reconnect(rc);
+}
+
+void
+rconn_connect_unreliably(struct rconn *rc,
+ const char *name, struct vconn *vconn)
{
assert(vconn != NULL);
- return create_rconn(name, txq_limit, 0, 0, vconn);
+ rconn_disconnect(rc);
+ free(rc->name);
+ rc->name = xstrdup(name);
+ rc->reliable = false;
+ rc->vconn = vconn;
+ rc->last_connected = time(0);
+ state_transition(rc, S_ACTIVE);
+}
+
+void
+rconn_disconnect(struct rconn *rc)
+{
+ if (rc->vconn) {
+ vconn_close(rc->vconn);
+ rc->vconn = NULL;
+ }
+ free(rc->name);
+ rc->name = xstrdup("void");
+ rc->reliable = false;
+
+ rc->backoff = 0;
+ rc->backoff_deadline = TIME_MIN;
+
+ state_transition(rc, S_VOID);
}
/* Disconnects 'rc' and frees the underlying storage. */
}
}
+static void
+run_VOID(struct rconn *rc)
+{
+ /* Nothing to do. */
+}
+
+static void
+reconnect(struct rconn *rc)
+{
+ int retval;
+
+ VLOG_WARN("%s: connecting...", rc->name);
+ retval = vconn_open(rc->name, &rc->vconn);
+ if (!retval) {
+ rc->backoff_deadline = time(0) + rc->backoff;
+ state_transition(rc, S_CONNECTING);
+ } else {
+ VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(retval));
+ disconnect(rc, 0);
+ }
+}
+
+static void
+run_BACKOFF(struct rconn *rc)
+{
+ if (timeout(rc, rc->backoff)) {
+ reconnect(rc);
+ }
+}
+
+static void
+run_CONNECTING(struct rconn *rc)
+{
+ int error = vconn_connect(rc->vconn);
+ if (!error) {
+ VLOG_WARN("%s: connected", rc->name);
+ if (vconn_is_passive(rc->vconn)) {
+ fatal(0, "%s: passive vconn not supported in switch",
+ rc->name);
+ }
+ state_transition(rc, S_ACTIVE);
+ rc->last_connected = rc->state_entered;
+ } else if (error != EAGAIN) {
+ VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(error));
+ disconnect(rc, error);
+ } else if (timeout(rc, MAX(1, rc->backoff))) {
+ VLOG_WARN("%s: connection timed out", rc->name);
+ rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
+ disconnect(rc, 0);
+ }
+}
+
+static void
+do_tx_work(struct rconn *rc)
+{
+ while (rc->txq.n > 0) {
+ int error = try_send(rc);
+ if (error) {
+ break;
+ }
+ }
+}
+
+static void
+run_ACTIVE(struct rconn *rc)
+{
+ if (rc->probe_interval) {
+ unsigned int base = MAX(rc->last_received, rc->state_entered);
+ unsigned int arg = base + rc->probe_interval - rc->state_entered;
+ if (timeout(rc, arg)) {
+ queue_push_tail(&rc->txq, make_echo_request());
+ VLOG_DBG("%s: idle %u seconds, sending inactivity probe",
+ rc->name, (unsigned int) (time(0) - base));
+ state_transition(rc, S_IDLE);
+ return;
+ }
+ }
+
+ do_tx_work(rc);
+}
+
+static void
+run_IDLE(struct rconn *rc)
+{
+ if (timeout(rc, rc->probe_interval)) {
+ VLOG_ERR("%s: no response to inactivity probe after %u "
+ "seconds, disconnecting",
+ rc->name, elapsed_in_this_state(rc));
+ disconnect(rc, 0);
+ } else {
+ do_tx_work(rc);
+ }
+}
+
/* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
* disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
* connected, attempts to send packets in the send queue, if any. */
void
rconn_run(struct rconn *rc)
{
- if (!rc->vconn) {
- if (rc->reliable && time(0) >= rc->backoff_deadline) {
- int retval;
-
- VLOG_WARN("%s: connecting...", rc->name);
- retval = vconn_open(rc->name, &rc->vconn);
- if (!retval) {
- rc->backoff_deadline = time(0) + rc->backoff;
- rc->connected = false;
- } else {
- VLOG_WARN("%s: connection failed (%s)",
- rc->name, strerror(retval));
- disconnect(rc, 0);
- }
+ int old_state;
+ do {
+ old_state = rc->state;
+ rc->min_timeout = UINT_MAX;
+ switch (rc->state) {
+#define STATE(NAME, VALUE) case S_##NAME: run_##NAME(rc); break;
+ STATES
+#undef STATE
+ default:
+ NOT_REACHED();
}
- } else if (!rc->connected) {
- int error = vconn_connect(rc->vconn);
- if (!error) {
- VLOG_WARN("%s: connected", rc->name);
- if (vconn_is_passive(rc->vconn)) {
- fatal(0, "%s: passive vconn not supported in switch",
- rc->name);
- }
- rc->connected = true;
- } else if (error != EAGAIN) {
- VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(error));
- disconnect(rc, 0);
- } else if (time(0) >= rc->backoff_deadline) {
- VLOG_WARN("%s: connection timed out", rc->name);
- rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
- disconnect(rc, 0);
- }
- } else {
- if (rc->probe_interval) {
- time_t now = time(0);
- if (now >= probe_deadline(rc)) {
- if (!rc->probe_sent) {
- queue_push_tail(&rc->txq, make_echo_request());
- rc->probe_sent = now;
- VLOG_DBG("%s: idle %d seconds, sending inactivity probe",
- rc->name, (int) (now - rc->last_connected));
- } else {
- VLOG_ERR("%s: no response to inactivity probe after %d "
- "seconds, disconnecting",
- rc->name, (int) (now - rc->probe_sent));
- disconnect(rc, 0);
- }
- }
- }
- while (rc->txq.n > 0) {
- int error = try_send(rc);
- if (error) {
- break;
- }
- }
- }
+ } while (rc->state != old_state);
}
/* Causes the next call to poll_block() to wake up when rconn_run() should be
void
rconn_run_wait(struct rconn *rc)
{
- if (rc->vconn) {
- if (rc->txq.n) {
- vconn_wait(rc->vconn, WAIT_SEND);
- }
- if (rc->probe_interval) {
- poll_timer_wait((probe_deadline(rc) - time(0)) * 1000);
- }
- } else {
- poll_timer_wait((rc->backoff_deadline - time(0)) * 1000);
+ if (rc->min_timeout != UINT_MAX) {
+ poll_timer_wait(sat_mul(rc->min_timeout, 1000));
}
-}
+ /* Reset timeout to 1 second. This will have no effect ordinarily, because
+ * rconn_run() will typically set it back to a higher value. If, however,
+ * the caller fails to call rconn_run() before its next call to
+ * rconn_wait() we won't potentially block forever. */
+ rc->min_timeout = 1;
-/* Returns the time at which, should nothing be received, we should send out an
- * inactivity probe (if none has yet been sent) or conclude that the connection
- * is dead (if a probe has already been sent). */
-static time_t
-probe_deadline(const struct rconn *rc)
-{
- assert(rc->probe_interval);
- return (rc->probe_interval
- + (rc->probe_sent ? rc->probe_sent : rc->last_connected));
+ if ((rc->state & (S_ACTIVE | S_IDLE)) && rc->txq.n) {
+ vconn_wait(rc->vconn, WAIT_SEND);
+ }
}
/* Attempts to receive a packet from 'rc'. If successful, returns the packet;
struct buffer *
rconn_recv(struct rconn *rc)
{
- if (rc->vconn && rc->connected) {
+ if (rc->state & (S_ACTIVE | S_IDLE)) {
struct buffer *buffer;
int error = vconn_recv(rc->vconn, &buffer);
if (!error) {
- rc->last_connected = time(0);
- rc->probe_sent = 0;
+ rc->last_received = time(0);
+ if (rc->state == S_IDLE) {
+ state_transition(rc, S_ACTIVE);
+ }
return buffer;
} else if (error != EAGAIN) {
- disconnect(rc, error);
+ disconnect(rc, error);
}
}
return NULL;
/* Causes the next call to poll_block() to wake up when a packet may be ready
* to be received by vconn_recv() on 'rc'. */
void
-rconn_recv_wait(struct rconn *rc)
+rconn_recv_wait(struct rconn *rc)
{
if (rc->vconn) {
vconn_wait(rc->vconn, WAIT_RECV);
/* Returns true if 'rc''s send buffer is full,
* false if it has room for at least one more packet. */
bool
-rconn_is_full(const struct rconn *rc)
+rconn_is_full(const struct rconn *rc)
{
return rc->txq.n >= rc->txq_limit;
}
* vconn. A packet is not counted as sent while it is still queued in the
* rconn, only when it has been successfuly passed to the vconn. */
unsigned int
-rconn_packets_sent(const struct rconn *rc)
+rconn_packets_sent(const struct rconn *rc)
{
return rc->packets_sent;
}
/* Returns 'rc''s name (the 'name' argument passed to rconn_new()). */
const char *
-rconn_get_name(const struct rconn *rc)
+rconn_get_name(const struct rconn *rc)
{
return rc->name;
}
/* Returns true if 'rconn' is connected or in the process of reconnecting,
- * false if 'rconn' is disconnected and will not be reconnected. */
+ * false if 'rconn' is disconnected and will not reconnect on its own. */
bool
-rconn_is_alive(const struct rconn *rconn)
+rconn_is_alive(const struct rconn *rconn)
{
return rconn->reliable || rconn->vconn;
}
bool
rconn_is_connected(const struct rconn *rconn)
{
- return rconn->vconn && !vconn_connect(rconn->vconn);
+ return rconn->state & (S_ACTIVE | S_IDLE);
}
/* Returns 0 if 'rconn' is connected, otherwise the number of seconds that it
* has been disconnected. */
int
-rconn_disconnected_duration(const struct rconn *rconn)
+rconn_disconnected_duration(const struct rconn *rconn)
{
return rconn_is_connected(rconn) ? 0 : time(0) - rconn->last_connected;
}
return rconn->vconn ? vconn_get_ip(rconn->vconn) : 0;
}
\f
-static struct rconn *
-create_rconn(const char *name, int txq_limit, int probe_interval,
- int max_backoff, struct vconn *vconn)
-{
- struct rconn *rc = xmalloc(sizeof *rc);
- assert(txq_limit > 0);
- rc->reliable = vconn == NULL;
- rc->connected = vconn != NULL;
- rc->name = xstrdup(name);
- rc->vconn = vconn;
- queue_init(&rc->txq);
- rc->txq_limit = txq_limit;
- rc->backoff_deadline = time(0);
- rc->backoff = 0;
- rc->max_backoff = max_backoff ? max_backoff : 60;
- rc->last_connected = time(0);
- rc->probe_interval = (probe_interval
- ? MAX(5, probe_interval) : 0);
- rc->probe_sent = 0;
- rc->packets_sent = 0;
- return rc;
-}
-
/* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
* otherwise a positive errno value. */
static int
* nonzero, then it should be EOF to indicate the connection was closed by the
* peer in a normal fashion or a positive errno value. */
static void
-disconnect(struct rconn *rc, int error)
+disconnect(struct rconn *rc, int error)
{
- time_t now = time(0);
-
- if (rc->vconn) {
- if (error > 0) {
- VLOG_WARN("%s: connection dropped (%s)",
- rc->name, strerror(error));
- } else if (error == EOF) {
- if (rc->reliable) {
- VLOG_WARN("%s: connection closed", rc->name);
+ if (rc->reliable) {
+ time_t now = time(0);
+
+ if (rc->state & (S_CONNECTING | S_ACTIVE | S_IDLE)) {
+ if (error > 0) {
+ VLOG_WARN("%s: connection dropped (%s)",
+ rc->name, strerror(error));
+ } else if (error == EOF) {
+ if (rc->reliable) {
+ VLOG_WARN("%s: connection closed", rc->name);
+ }
+ } else {
+ VLOG_WARN("%s: connection dropped", rc->name);
}
- } else {
- VLOG_WARN("%s: connection dropped", rc->name);
+ vconn_close(rc->vconn);
+ rc->vconn = NULL;
+ queue_clear(&rc->txq);
}
- vconn_close(rc->vconn);
- rc->vconn = NULL;
- queue_clear(&rc->txq);
- }
- if (now >= rc->backoff_deadline) {
- rc->backoff = 1;
+ if (now >= rc->backoff_deadline) {
+ rc->backoff = 1;
+ } else {
+ rc->backoff = MIN(rc->max_backoff, MAX(1, 2 * rc->backoff));
+ VLOG_WARN("%s: waiting %d seconds before reconnect\n",
+ rc->name, rc->backoff);
+ }
+ rc->backoff_deadline = now + rc->backoff;
+ state_transition(rc, S_BACKOFF);
} else {
- rc->backoff = MIN(rc->max_backoff, MAX(1, 2 * rc->backoff));
- VLOG_WARN("%s: waiting %d seconds before reconnect\n",
- rc->name, rc->backoff);
+ rconn_disconnect(rc);
}
- rc->backoff_deadline = now + rc->backoff;
- rc->probe_sent = 0;
+}
+
+static unsigned int
+elapsed_in_this_state(const struct rconn *rc)
+{
+ return time(0) - rc->state_entered;
+}
+
+static bool
+timeout(struct rconn *rc, unsigned int secs)
+{
+ rc->min_timeout = MIN(rc->min_timeout, secs);
+ return time(0) >= sat_add(rc->state_entered, secs);
+}
+
+static void
+state_transition(struct rconn *rc, enum state state)
+{
+ VLOG_DBG("%s: entering %s", rc->name, state_name(state));
+ rc->state = state;
+ rc->state_entered = time(0);
+}
+
+static unsigned int
+sat_add(unsigned int x, unsigned int y)
+{
+ return x + y >= x ? x + y : UINT_MAX;
+}
+
+static unsigned int
+sat_mul(unsigned int x, unsigned int y)
+{
+ assert(y);
+ return x <= UINT_MAX / y ? x * y : UINT_MAX;
}
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