2 * Copyright (c) 2009, 2010 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
20 /* This library implements a finite-state machine for connecting and
21 * reconnecting to a network resource with exponential backoff. It also
22 * provides optional support for detecting a connection on which the peer is no
25 * The library does not implement anything networking related, only an FSM for
26 * networking code to use.
28 * Many "reconnect" functions take a "now" argument. This makes testing easier
29 * since there is no hidden state. When not testing, just pass the return
30 * value of time_msec() from timeval.h. (Perhaps this design should be
31 * revisited later.) */
35 struct reconnect *reconnect_create(long long int now);
36 void reconnect_destroy(struct reconnect *);
38 void reconnect_set_quiet(struct reconnect *, bool quiet);
40 const char *reconnect_get_name(const struct reconnect *);
41 void reconnect_set_name(struct reconnect *, const char *name);
43 /* Defaults, all in msecs. */
44 #define RECONNECT_DEFAULT_MIN_BACKOFF 1000
45 #define RECONNECT_DEFAULT_MAX_BACKOFF 8000
46 #define RECONNECT_DEFAULT_PROBE_INTERVAL 5000
48 int reconnect_get_min_backoff(const struct reconnect *);
49 int reconnect_get_max_backoff(const struct reconnect *);
50 int reconnect_get_probe_interval(const struct reconnect *);
52 void reconnect_set_max_tries(struct reconnect *, unsigned int max_tries);
53 unsigned int reconnect_get_max_tries(struct reconnect *);
55 void reconnect_set_backoff(struct reconnect *,
56 int min_backoff, int max_backoff);
57 void reconnect_set_probe_interval(struct reconnect *, int probe_interval);
59 bool reconnect_is_passive(const struct reconnect *);
60 void reconnect_set_passive(struct reconnect *, bool passive,
63 bool reconnect_is_enabled(const struct reconnect *);
64 void reconnect_enable(struct reconnect *, long long int now);
65 void reconnect_disable(struct reconnect *, long long int now);
67 void reconnect_force_reconnect(struct reconnect *, long long int now);
69 bool reconnect_is_connected(const struct reconnect *);
70 unsigned int reconnect_get_last_connect_elapsed(const struct reconnect *,
72 unsigned int reconnect_get_last_disconnect_elapsed(const struct reconnect *,
75 void reconnect_disconnected(struct reconnect *, long long int now, int error);
76 void reconnect_connecting(struct reconnect *, long long int now);
77 void reconnect_listening(struct reconnect *, long long int now);
78 void reconnect_listen_error(struct reconnect *, long long int now, int error);
79 void reconnect_connected(struct reconnect *, long long int now);
80 void reconnect_connect_failed(struct reconnect *, long long int now,
82 void reconnect_received(struct reconnect *, long long int now);
84 enum reconnect_action {
85 RECONNECT_CONNECT = 1,
89 enum reconnect_action reconnect_run(struct reconnect *, long long int now);
90 void reconnect_wait(struct reconnect *, long long int now);
91 int reconnect_timeout(struct reconnect *, long long int now);
93 struct reconnect_stats {
94 /* All times and durations in this structure are in milliseconds. */
95 long long int creation_time; /* Time reconnect_create() called. */
96 long long int last_received; /* Last call to reconnect_received(). */
97 long long int last_connected; /* Last call to reconnect_connected(). */
98 long long int last_disconnected; /* Last call to reconnect_disconnected(). */
99 int backoff; /* Current backoff duration. */
101 unsigned int seqno; /* # of connections + # of disconnections. */
103 bool is_connected; /* Currently connected? */
104 unsigned int msec_since_connect; /* Time since last connect. */
105 unsigned int msec_since_disconnect; /* Time since last disconnect. */
106 unsigned int total_connected_duration; /* Sum of all connections. */
107 unsigned int n_attempted_connections;
108 unsigned int n_successful_connections;
110 /* These should only be provided to a human user for debugging purposes.
111 * The client should not attempt to interpret them. */
112 const char *state; /* FSM state. */
113 unsigned int state_elapsed; /* Time since FSM state entered. */
116 void reconnect_get_stats(const struct reconnect *, long long int now,
117 struct reconnect_stats *);
119 #endif /* reconnect.h */