/usr/src/openvswitch-1.4.0/lib/rconn.c is in openvswitch-datapath-dkms 1.4.0-1ubuntu1.
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* Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "rconn.h"
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "coverage.h"
#include "ofp-util.h"
#include "ofpbuf.h"
#include "openflow/openflow.h"
#include "poll-loop.h"
#include "sat-math.h"
#include "timeval.h"
#include "util.h"
#include "vconn.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(rconn);
COVERAGE_DEFINE(rconn_discarded);
COVERAGE_DEFINE(rconn_overflow);
COVERAGE_DEFINE(rconn_queued);
COVERAGE_DEFINE(rconn_sent);
#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 {
enum state state;
time_t state_entered;
struct vconn *vconn;
char *name; /* Human-readable descriptive name. */
char *target; /* vconn name, passed to vconn_open(). */
bool reliable;
struct list txq; /* Contains "struct ofpbuf"s. */
int backoff;
int max_backoff;
time_t backoff_deadline;
time_t last_received;
time_t last_connected;
time_t last_disconnected;
unsigned int packets_sent;
unsigned int seqno;
int last_error;
/* In S_ACTIVE and S_IDLE, probably_admitted reports whether we believe
* that the peer has made a (positive) admission control decision on our
* connection. If we have not yet been (probably) admitted, then the
* connection does not reset the timer used for deciding whether the switch
* should go into fail-open mode.
*
* last_admitted reports the last time we believe such a positive admission
* control decision was made. */
bool probably_admitted;
time_t last_admitted;
/* These values are simply for statistics reporting, not used directly by
* anything internal to the rconn (or ofproto for that matter). */
unsigned int packets_received;
unsigned int n_attempted_connections, n_successful_connections;
time_t creation_time;
unsigned long int total_time_connected;
/* Throughout this file, "probe" is shorthand for "inactivity probe".
* When nothing has been received from the peer for a while, we send out
* an echo request as an inactivity probe packet. We should receive back
* a response. */
int probe_interval; /* Secs of inactivity before sending probe. */
/* When we create a vconn we obtain these values, to save them past the end
* of the vconn's lifetime. Otherwise, in-band control will only allow
* traffic when a vconn is actually open, but it is nice to allow ARP to
* complete even between connection attempts, and it is also polite to
* allow traffic from other switches to go through to the controller
* whether or not we are connected.
*
* We don't cache the local port, because that changes from one connection
* attempt to the next. */
ovs_be32 local_ip, remote_ip;
ovs_be16 remote_port;
/* Messages sent or received are copied to the monitor connections. */
#define MAX_MONITORS 8
struct vconn *monitors[8];
size_t n_monitors;
};
static unsigned int elapsed_in_this_state(const struct rconn *);
static unsigned int timeout(const struct rconn *);
static bool timed_out(const struct rconn *);
static void state_transition(struct rconn *, enum state);
static void rconn_set_target__(struct rconn *,
const char *target, const char *name);
static int try_send(struct rconn *);
static void reconnect(struct rconn *);
static void report_error(struct rconn *, int error);
static void disconnect(struct rconn *, int error);
static void flush_queue(struct rconn *);
static void copy_to_monitor(struct rconn *, const struct ofpbuf *);
static bool is_connected_state(enum state);
static bool is_admitted_msg(const struct ofpbuf *);
static bool rconn_logging_connection_attempts__(const struct rconn *);
/* Creates and returns a new rconn.
*
* 'probe_interval' is a number of seconds. If the interval passes once
* without an OpenFlow message being received from the peer, the rconn sends
* out an "echo request" message. If the interval passes again without a
* message being received, the rconn disconnects and re-connects to the peer.
* Setting 'probe_interval' to 0 disables this behavior.
*
* 'max_backoff' is the maximum number of seconds between attempts to connect
* to the peer. The actual interval starts at 1 second and doubles on each
* failure until it reaches 'max_backoff'. If 0 is specified, the default of
* 8 seconds is used.
*
* The new rconn is initially unconnected. Use rconn_connect() or
* rconn_connect_unreliably() to connect it. */
struct rconn *
rconn_create(int probe_interval, int max_backoff)
{
struct rconn *rc = xzalloc(sizeof *rc);
rc->state = S_VOID;
rc->state_entered = time_now();
rc->vconn = NULL;
rc->name = xstrdup("void");
rc->target = xstrdup("void");
rc->reliable = false;
list_init(&rc->txq);
rc->backoff = 0;
rc->max_backoff = max_backoff ? max_backoff : 8;
rc->backoff_deadline = TIME_MIN;
rc->last_received = time_now();
rc->last_connected = TIME_MIN;
rc->last_disconnected = TIME_MIN;
rc->seqno = 0;
rc->packets_sent = 0;
rc->probably_admitted = false;
rc->last_admitted = time_now();
rc->packets_received = 0;
rc->n_attempted_connections = 0;
rc->n_successful_connections = 0;
rc->creation_time = time_now();
rc->total_time_connected = 0;
rconn_set_probe_interval(rc, probe_interval);
rc->n_monitors = 0;
return rc;
}
void
rconn_set_max_backoff(struct rconn *rc, int max_backoff)
{
rc->max_backoff = MAX(1, max_backoff);
if (rc->state == S_BACKOFF && rc->backoff > max_backoff) {
rc->backoff = max_backoff;
if (rc->backoff_deadline > time_now() + max_backoff) {
rc->backoff_deadline = time_now() + max_backoff;
}
}
}
int
rconn_get_max_backoff(const struct rconn *rc)
{
return rc->max_backoff;
}
void
rconn_set_probe_interval(struct rconn *rc, int probe_interval)
{
rc->probe_interval = probe_interval ? MAX(5, probe_interval) : 0;
}
int
rconn_get_probe_interval(const struct rconn *rc)
{
return rc->probe_interval;
}
/* Drops any existing connection on 'rc', then sets up 'rc' to connect to
* 'target' and reconnect as needed. 'target' should be a remote OpenFlow
* target in a form acceptable to vconn_open().
*
* If 'name' is nonnull, then it is used in log messages in place of 'target'.
* It should presumably give more information to a human reader than 'target',
* but it need not be acceptable to vconn_open(). */
void
rconn_connect(struct rconn *rc, const char *target, const char *name)
{
rconn_disconnect(rc);
rconn_set_target__(rc, target, name);
rc->reliable = true;
reconnect(rc);
}
/* Drops any existing connection on 'rc', then configures 'rc' to use
* 'vconn'. If the connection on 'vconn' drops, 'rc' will not reconnect on it
* own.
*
* By default, the target obtained from vconn_get_name(vconn) is used in log
* messages. If 'name' is nonnull, then it is used instead. It should
* presumably give more information to a human reader than the target, but it
* need not be acceptable to vconn_open(). */
void
rconn_connect_unreliably(struct rconn *rc,
struct vconn *vconn, const char *name)
{
assert(vconn != NULL);
rconn_disconnect(rc);
rconn_set_target__(rc, vconn_get_name(vconn), name);
rc->reliable = false;
rc->vconn = vconn;
rc->last_connected = time_now();
state_transition(rc, S_ACTIVE);
}
/* If 'rc' is connected, forces it to drop the connection and reconnect. */
void
rconn_reconnect(struct rconn *rc)
{
if (rc->state & (S_ACTIVE | S_IDLE)) {
VLOG_INFO("%s: disconnecting", rc->name);
disconnect(rc, 0);
}
}
void
rconn_disconnect(struct rconn *rc)
{
if (rc->state != S_VOID) {
if (rc->vconn) {
vconn_close(rc->vconn);
rc->vconn = NULL;
}
rconn_set_target__(rc, "void", NULL);
rc->reliable = false;
rc->backoff = 0;
rc->backoff_deadline = TIME_MIN;
state_transition(rc, S_VOID);
}
}
/* Disconnects 'rc' and frees the underlying storage. */
void
rconn_destroy(struct rconn *rc)
{
if (rc) {
size_t i;
free(rc->name);
free(rc->target);
vconn_close(rc->vconn);
flush_queue(rc);
ofpbuf_list_delete(&rc->txq);
for (i = 0; i < rc->n_monitors; i++) {
vconn_close(rc->monitors[i]);
}
free(rc);
}
}
static unsigned int
timeout_VOID(const struct rconn *rc OVS_UNUSED)
{
return UINT_MAX;
}
static void
run_VOID(struct rconn *rc OVS_UNUSED)
{
/* Nothing to do. */
}
static void
reconnect(struct rconn *rc)
{
int retval;
if (rconn_logging_connection_attempts__(rc)) {
VLOG_INFO("%s: connecting...", rc->name);
}
rc->n_attempted_connections++;
retval = vconn_open(rc->target, OFP_VERSION, &rc->vconn);
if (!retval) {
rc->remote_ip = vconn_get_remote_ip(rc->vconn);
rc->local_ip = vconn_get_local_ip(rc->vconn);
rc->remote_port = vconn_get_remote_port(rc->vconn);
rc->backoff_deadline = time_now() + rc->backoff;
state_transition(rc, S_CONNECTING);
} else {
VLOG_WARN("%s: connection failed (%s)", rc->name, strerror(retval));
rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
disconnect(rc, retval);
}
}
static unsigned int
timeout_BACKOFF(const struct rconn *rc)
{
return rc->backoff;
}
static void
run_BACKOFF(struct rconn *rc)
{
if (timed_out(rc)) {
reconnect(rc);
}
}
static unsigned int
timeout_CONNECTING(const struct rconn *rc)
{
return MAX(1, rc->backoff);
}
static void
run_CONNECTING(struct rconn *rc)
{
int retval = vconn_connect(rc->vconn);
if (!retval) {
VLOG_INFO("%s: connected", rc->name);
rc->n_successful_connections++;
state_transition(rc, S_ACTIVE);
rc->last_connected = rc->state_entered;
} else if (retval != EAGAIN) {
if (rconn_logging_connection_attempts__(rc)) {
VLOG_INFO("%s: connection failed (%s)",
rc->name, strerror(retval));
}
disconnect(rc, retval);
} else if (timed_out(rc)) {
if (rconn_logging_connection_attempts__(rc)) {
VLOG_INFO("%s: connection timed out", rc->name);
}
rc->backoff_deadline = TIME_MAX; /* Prevent resetting backoff. */
disconnect(rc, ETIMEDOUT);
}
}
static void
do_tx_work(struct rconn *rc)
{
if (list_is_empty(&rc->txq)) {
return;
}
while (!list_is_empty(&rc->txq)) {
int error = try_send(rc);
if (error) {
break;
}
}
if (list_is_empty(&rc->txq)) {
poll_immediate_wake();
}
}
static unsigned int
timeout_ACTIVE(const 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;
return arg;
}
return UINT_MAX;
}
static void
run_ACTIVE(struct rconn *rc)
{
if (timed_out(rc)) {
unsigned int base = MAX(rc->last_received, rc->state_entered);
VLOG_DBG("%s: idle %u seconds, sending inactivity probe",
rc->name, (unsigned int) (time_now() - base));
/* Ordering is important here: rconn_send() can transition to BACKOFF,
* and we don't want to transition back to IDLE if so, because then we
* can end up queuing a packet with vconn == NULL and then *boom*. */
state_transition(rc, S_IDLE);
rconn_send(rc, make_echo_request(), NULL);
return;
}
do_tx_work(rc);
}
static unsigned int
timeout_IDLE(const struct rconn *rc)
{
return rc->probe_interval;
}
static void
run_IDLE(struct rconn *rc)
{
if (timed_out(rc)) {
VLOG_ERR("%s: no response to inactivity probe after %u "
"seconds, disconnecting",
rc->name, elapsed_in_this_state(rc));
disconnect(rc, ETIMEDOUT);
} 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)
{
int old_state;
size_t i;
if (rc->vconn) {
vconn_run(rc->vconn);
}
for (i = 0; i < rc->n_monitors; i++) {
vconn_run(rc->monitors[i]);
}
do {
old_state = rc->state;
switch (rc->state) {
#define STATE(NAME, VALUE) case S_##NAME: run_##NAME(rc); break;
STATES
#undef STATE
default:
NOT_REACHED();
}
} while (rc->state != old_state);
}
/* Causes the next call to poll_block() to wake up when rconn_run() should be
* called on 'rc'. */
void
rconn_run_wait(struct rconn *rc)
{
unsigned int timeo;
size_t i;
if (rc->vconn) {
vconn_run_wait(rc->vconn);
if ((rc->state & (S_ACTIVE | S_IDLE)) && !list_is_empty(&rc->txq)) {
vconn_wait(rc->vconn, WAIT_SEND);
}
}
for (i = 0; i < rc->n_monitors; i++) {
vconn_run_wait(rc->monitors[i]);
}
timeo = timeout(rc);
if (timeo != UINT_MAX) {
long long int expires = sat_add(rc->state_entered, timeo);
poll_timer_wait_until(expires * 1000);
}
}
/* Attempts to receive a packet from 'rc'. If successful, returns the packet;
* otherwise, returns a null pointer. The caller is responsible for freeing
* the packet (with ofpbuf_delete()). */
struct ofpbuf *
rconn_recv(struct rconn *rc)
{
if (rc->state & (S_ACTIVE | S_IDLE)) {
struct ofpbuf *buffer;
int error = vconn_recv(rc->vconn, &buffer);
if (!error) {
copy_to_monitor(rc, buffer);
if (rc->probably_admitted || is_admitted_msg(buffer)
|| time_now() - rc->last_connected >= 30) {
rc->probably_admitted = true;
rc->last_admitted = time_now();
}
rc->last_received = time_now();
rc->packets_received++;
if (rc->state == S_IDLE) {
state_transition(rc, S_ACTIVE);
}
return buffer;
} else if (error != EAGAIN) {
report_error(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)
{
if (rc->vconn) {
vconn_wait(rc->vconn, WAIT_RECV);
}
}
/* Sends 'b' on 'rc'. Returns 0 if successful (in which case 'b' is
* destroyed), or ENOTCONN if 'rc' is not currently connected (in which case
* the caller retains ownership of 'b').
*
* If 'counter' is non-null, then 'counter' will be incremented while the
* packet is in flight, then decremented when it has been sent (or discarded
* due to disconnection). Because 'b' may be sent (or discarded) before this
* function returns, the caller may not be able to observe any change in
* 'counter'.
*
* There is no rconn_send_wait() function: an rconn has a send queue that it
* takes care of sending if you call rconn_run(), which will have the side
* effect of waking up poll_block(). */
int
rconn_send(struct rconn *rc, struct ofpbuf *b,
struct rconn_packet_counter *counter)
{
if (rconn_is_connected(rc)) {
COVERAGE_INC(rconn_queued);
copy_to_monitor(rc, b);
b->private_p = counter;
if (counter) {
rconn_packet_counter_inc(counter);
}
list_push_back(&rc->txq, &b->list_node);
/* If the queue was empty before we added 'b', try to send some
* packets. (But if the queue had packets in it, it's because the
* vconn is backlogged and there's no point in stuffing more into it
* now. We'll get back to that in rconn_run().) */
if (rc->txq.next == &b->list_node) {
try_send(rc);
}
return 0;
} else {
return ENOTCONN;
}
}
/* Sends 'b' on 'rc'. Increments 'counter' while the packet is in flight; it
* will be decremented when it has been sent (or discarded due to
* disconnection). Returns 0 if successful, EAGAIN if 'counter->n' is already
* at least as large as 'queue_limit', or ENOTCONN if 'rc' is not currently
* connected. Regardless of return value, 'b' is destroyed.
*
* Because 'b' may be sent (or discarded) before this function returns, the
* caller may not be able to observe any change in 'counter'.
*
* There is no rconn_send_wait() function: an rconn has a send queue that it
* takes care of sending if you call rconn_run(), which will have the side
* effect of waking up poll_block(). */
int
rconn_send_with_limit(struct rconn *rc, struct ofpbuf *b,
struct rconn_packet_counter *counter, int queue_limit)
{
int retval;
retval = counter->n >= queue_limit ? EAGAIN : rconn_send(rc, b, counter);
if (retval) {
COVERAGE_INC(rconn_overflow);
ofpbuf_delete(b);
}
return retval;
}
/* Returns the total number of packets successfully sent on the underlying
* 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)
{
return rc->packets_sent;
}
/* Adds 'vconn' to 'rc' as a monitoring connection, to which all messages sent
* and received on 'rconn' will be copied. 'rc' takes ownership of 'vconn'. */
void
rconn_add_monitor(struct rconn *rc, struct vconn *vconn)
{
if (rc->n_monitors < ARRAY_SIZE(rc->monitors)) {
VLOG_INFO("new monitor connection from %s", vconn_get_name(vconn));
rc->monitors[rc->n_monitors++] = vconn;
} else {
VLOG_DBG("too many monitor connections, discarding %s",
vconn_get_name(vconn));
vconn_close(vconn);
}
}
/* Returns 'rc''s name. This is a name for human consumption, appropriate for
* use in log messages. It is not necessarily a name that may be passed
* directly to, e.g., vconn_open(). */
const char *
rconn_get_name(const struct rconn *rc)
{
return rc->name;
}
/* Sets 'rc''s name to 'new_name'. */
void
rconn_set_name(struct rconn *rc, const char *new_name)
{
free(rc->name);
rc->name = xstrdup(new_name);
}
/* Returns 'rc''s target. This is intended to be a string that may be passed
* directly to, e.g., vconn_open(). */
const char *
rconn_get_target(const struct rconn *rc)
{
return rc->target;
}
/* Returns true if 'rconn' is connected or in the process of reconnecting,
* false if 'rconn' is disconnected and will not reconnect on its own. */
bool
rconn_is_alive(const struct rconn *rconn)
{
return rconn->state != S_VOID;
}
/* Returns true if 'rconn' is connected, false otherwise. */
bool
rconn_is_connected(const struct rconn *rconn)
{
return is_connected_state(rconn->state);
}
/* Returns true if 'rconn' is connected and thought to have been accepted by
* the peer's admission-control policy. */
bool
rconn_is_admitted(const struct rconn *rconn)
{
return (rconn_is_connected(rconn)
&& rconn->last_admitted >= rconn->last_connected);
}
/* Returns 0 if 'rconn' is currently connected and considered to have been
* accepted by the peer's admission-control policy, otherwise the number of
* seconds since 'rconn' was last in such a state. */
int
rconn_failure_duration(const struct rconn *rconn)
{
return rconn_is_admitted(rconn) ? 0 : time_now() - rconn->last_admitted;
}
/* Returns the IP address of the peer, or 0 if the peer's IP address is not
* known. */
ovs_be32
rconn_get_remote_ip(const struct rconn *rconn)
{
return rconn->remote_ip;
}
/* Returns the transport port of the peer, or 0 if the peer's port is not
* known. */
ovs_be16
rconn_get_remote_port(const struct rconn *rconn)
{
return rconn->remote_port;
}
/* Returns the IP address used to connect to the peer, or 0 if the
* connection is not an IP-based protocol or if its IP address is not
* known. */
ovs_be32
rconn_get_local_ip(const struct rconn *rconn)
{
return rconn->local_ip;
}
/* Returns the transport port used to connect to the peer, or 0 if the
* connection does not contain a port or if the port is not known. */
ovs_be16
rconn_get_local_port(const struct rconn *rconn)
{
return rconn->vconn ? vconn_get_local_port(rconn->vconn) : 0;
}
/* Returns the total number of packets successfully received by the underlying
* vconn. */
unsigned int
rconn_packets_received(const struct rconn *rc)
{
return rc->packets_received;
}
/* Returns a string representing the internal state of 'rc'. The caller must
* not modify or free the string. */
const char *
rconn_get_state(const struct rconn *rc)
{
return state_name(rc->state);
}
/* Returns the number of connection attempts made by 'rc', including any
* ongoing attempt that has not yet succeeded or failed. */
unsigned int
rconn_get_attempted_connections(const struct rconn *rc)
{
return rc->n_attempted_connections;
}
/* Returns the number of successful connection attempts made by 'rc'. */
unsigned int
rconn_get_successful_connections(const struct rconn *rc)
{
return rc->n_successful_connections;
}
/* Returns the time at which the last successful connection was made by
* 'rc'. Returns TIME_MIN if never connected. */
time_t
rconn_get_last_connection(const struct rconn *rc)
{
return rc->last_connected;
}
/* Returns the time at which 'rc' was last disconnected. Returns TIME_MIN
* if never disconnected. */
time_t
rconn_get_last_disconnect(const struct rconn *rc)
{
return rc->last_disconnected;
}
/* Returns the time at which the last OpenFlow message was received by 'rc'.
* If no packets have been received on 'rc', returns the time at which 'rc'
* was created. */
time_t
rconn_get_last_received(const struct rconn *rc)
{
return rc->last_received;
}
/* Returns the time at which 'rc' was created. */
time_t
rconn_get_creation_time(const struct rconn *rc)
{
return rc->creation_time;
}
/* Returns the approximate number of seconds that 'rc' has been connected. */
unsigned long int
rconn_get_total_time_connected(const struct rconn *rc)
{
return (rc->total_time_connected
+ (rconn_is_connected(rc) ? elapsed_in_this_state(rc) : 0));
}
/* Returns the current amount of backoff, in seconds. This is the amount of
* time after which the rconn will transition from BACKOFF to CONNECTING. */
int
rconn_get_backoff(const struct rconn *rc)
{
return rc->backoff;
}
/* Returns the number of seconds spent in this state so far. */
unsigned int
rconn_get_state_elapsed(const struct rconn *rc)
{
return elapsed_in_this_state(rc);
}
/* Returns 'rc''s current connection sequence number, a number that changes
* every time that 'rconn' connects or disconnects. */
unsigned int
rconn_get_connection_seqno(const struct rconn *rc)
{
return rc->seqno;
}
/* Returns a value that explains why 'rc' last disconnected:
*
* - 0 means that the last disconnection was caused by a call to
* rconn_disconnect(), or that 'rc' is new and has not yet completed its
* initial connection or connection attempt.
*
* - EOF means that the connection was closed in the normal way by the peer.
*
* - A positive integer is an errno value that represents the error.
*/
int
rconn_get_last_error(const struct rconn *rc)
{
return rc->last_error;
}
struct rconn_packet_counter *
rconn_packet_counter_create(void)
{
struct rconn_packet_counter *c = xmalloc(sizeof *c);
c->n = 0;
c->ref_cnt = 1;
return c;
}
void
rconn_packet_counter_destroy(struct rconn_packet_counter *c)
{
if (c) {
assert(c->ref_cnt > 0);
if (!--c->ref_cnt && !c->n) {
free(c);
}
}
}
void
rconn_packet_counter_inc(struct rconn_packet_counter *c)
{
c->n++;
}
void
rconn_packet_counter_dec(struct rconn_packet_counter *c)
{
assert(c->n > 0);
if (!--c->n && !c->ref_cnt) {
free(c);
}
}
/* Set rc->target and rc->name to 'target' and 'name', respectively. If 'name'
* is null, 'target' is used.
*
* Also, clear out the cached IP address and port information, since changing
* the target also likely changes these values. */
static void
rconn_set_target__(struct rconn *rc, const char *target, const char *name)
{
free(rc->name);
rc->name = xstrdup(name ? name : target);
free(rc->target);
rc->target = xstrdup(target);
rc->local_ip = 0;
rc->remote_ip = 0;
rc->remote_port = 0;
}
/* Tries to send a packet from 'rc''s send buffer. Returns 0 if successful,
* otherwise a positive errno value. */
static int
try_send(struct rconn *rc)
{
struct ofpbuf *msg = ofpbuf_from_list(rc->txq.next);
struct rconn_packet_counter *counter = msg->private_p;
int retval;
/* Eagerly remove 'msg' from the txq. We can't remove it from the list
* after sending, if sending is successful, because it is then owned by the
* vconn, which might have freed it already. */
list_remove(&msg->list_node);
retval = vconn_send(rc->vconn, msg);
if (retval) {
list_push_front(&rc->txq, &msg->list_node);
if (retval != EAGAIN) {
report_error(rc, retval);
disconnect(rc, retval);
}
return retval;
}
COVERAGE_INC(rconn_sent);
rc->packets_sent++;
if (counter) {
rconn_packet_counter_dec(counter);
}
return 0;
}
/* Reports that 'error' caused 'rc' to disconnect. 'error' may be a positive
* errno value, or it may be EOF to indicate that the connection was closed
* normally. */
static void
report_error(struct rconn *rc, int error)
{
if (error == EOF) {
/* If 'rc' isn't reliable, then we don't really expect this connection
* to last forever anyway (probably it's a connection that we received
* via accept()), so use DBG level to avoid cluttering the logs. */
enum vlog_level level = rc->reliable ? VLL_INFO : VLL_DBG;
VLOG(level, "%s: connection closed by peer", rc->name);
} else {
VLOG_WARN("%s: connection dropped (%s)", rc->name, strerror(error));
}
}
/* Disconnects 'rc' and records 'error' as the error that caused 'rc''s last
* disconnection:
*
* - 0 means that this disconnection is due to a request by 'rc''s client,
* not due to any kind of network error.
*
* - EOF means that the connection was closed in the normal way by the peer.
*
* - A positive integer is an errno value that represents the error.
*/
static void
disconnect(struct rconn *rc, int error)
{
rc->last_error = error;
if (rc->reliable) {
time_t now = time_now();
if (rc->state & (S_CONNECTING | S_ACTIVE | S_IDLE)) {
rc->last_disconnected = now;
vconn_close(rc->vconn);
rc->vconn = NULL;
flush_queue(rc);
}
if (now >= rc->backoff_deadline) {
rc->backoff = 1;
} else if (rc->backoff < rc->max_backoff / 2) {
rc->backoff = MAX(1, 2 * rc->backoff);
VLOG_INFO("%s: waiting %d seconds before reconnect",
rc->name, rc->backoff);
} else {
if (rconn_logging_connection_attempts__(rc)) {
VLOG_INFO("%s: continuing to retry connections in the "
"background but suppressing further logging",
rc->name);
}
rc->backoff = rc->max_backoff;
}
rc->backoff_deadline = now + rc->backoff;
state_transition(rc, S_BACKOFF);
} else {
rc->last_disconnected = time_now();
rconn_disconnect(rc);
}
}
/* Drops all the packets from 'rc''s send queue and decrements their queue
* counts. */
static void
flush_queue(struct rconn *rc)
{
if (list_is_empty(&rc->txq)) {
return;
}
while (!list_is_empty(&rc->txq)) {
struct ofpbuf *b = ofpbuf_from_list(list_pop_front(&rc->txq));
struct rconn_packet_counter *counter = b->private_p;
if (counter) {
rconn_packet_counter_dec(counter);
}
COVERAGE_INC(rconn_discarded);
ofpbuf_delete(b);
}
poll_immediate_wake();
}
static unsigned int
elapsed_in_this_state(const struct rconn *rc)
{
return time_now() - rc->state_entered;
}
static unsigned int
timeout(const struct rconn *rc)
{
switch (rc->state) {
#define STATE(NAME, VALUE) case S_##NAME: return timeout_##NAME(rc);
STATES
#undef STATE
default:
NOT_REACHED();
}
}
static bool
timed_out(const struct rconn *rc)
{
return time_now() >= sat_add(rc->state_entered, timeout(rc));
}
static void
state_transition(struct rconn *rc, enum state state)
{
rc->seqno += (rc->state == S_ACTIVE) != (state == S_ACTIVE);
if (is_connected_state(state) && !is_connected_state(rc->state)) {
rc->probably_admitted = false;
}
if (rconn_is_connected(rc)) {
rc->total_time_connected += elapsed_in_this_state(rc);
}
VLOG_DBG("%s: entering %s", rc->name, state_name(state));
rc->state = state;
rc->state_entered = time_now();
}
static void
copy_to_monitor(struct rconn *rc, const struct ofpbuf *b)
{
struct ofpbuf *clone = NULL;
int retval;
size_t i;
for (i = 0; i < rc->n_monitors; ) {
struct vconn *vconn = rc->monitors[i];
if (!clone) {
clone = ofpbuf_clone(b);
}
retval = vconn_send(vconn, clone);
if (!retval) {
clone = NULL;
} else if (retval != EAGAIN) {
VLOG_DBG("%s: closing monitor connection to %s: %s",
rconn_get_name(rc), vconn_get_name(vconn),
strerror(retval));
rc->monitors[i] = rc->monitors[--rc->n_monitors];
continue;
}
i++;
}
ofpbuf_delete(clone);
}
static bool
is_connected_state(enum state state)
{
return (state & (S_ACTIVE | S_IDLE)) != 0;
}
static bool
is_admitted_msg(const struct ofpbuf *b)
{
struct ofp_header *oh = b->data;
uint8_t type = oh->type;
return !(type < 32
&& (1u << type) & ((1u << OFPT_HELLO) |
(1u << OFPT_ERROR) |
(1u << OFPT_ECHO_REQUEST) |
(1u << OFPT_ECHO_REPLY) |
(1u << OFPT_VENDOR) |
(1u << OFPT_FEATURES_REQUEST) |
(1u << OFPT_FEATURES_REPLY) |
(1u << OFPT_GET_CONFIG_REQUEST) |
(1u << OFPT_GET_CONFIG_REPLY) |
(1u << OFPT_SET_CONFIG)));
}
/* Returns true if 'rc' is currently logging information about connection
* attempts, false if logging should be suppressed because 'rc' hasn't
* successuflly connected in too long. */
static bool
rconn_logging_connection_attempts__(const struct rconn *rc)
{
return rc->backoff < rc->max_backoff;
}
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