lwIP - A Lightweight TCP/IP stack - Bugs: bug #59561, [mqtt] Stop sending a keep-alive...
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bug #59561: [mqtt] Stop sending a keep-alive if the connection is closed for a previously unacked keep-alive
Submitter: | Giuseppe Modugno <giusloq> | ||
Submitted: | Fri 27 Nov 2020 05:38:25 PM UTC | ||
Category: | apps | Severity: | 3 - Normal |
Item Group: | Faulty Behaviour | Status: | None |
Privacy: | Public | Assigned to: | None |
Open/Closed: | Open | Planned Release: | None |
lwIP version: | git head |
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Depends on the following items: None found
Items that depend on this one: None found
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Corresponding source code
In mqtt_cyclic_timer() I read:
if (client->keep_alive > 0) {
client->server_watchdog++;
/* If reception from server has been idle for 1.5*keep_alive time, server is considered unresponsive */
if ((client->server_watchdog * MQTT_CYCLIC_TIMER_INTERVAL) > (client->keep_alive + client->keep_alive / 2)) {
LWIP_DEBUGF(MQTT_DEBUG_WARN, ("mqtt_cyclic_timer: Server incoming keep-alive timeout\n"));
mqtt_close(client, MQTT_CONNECT_TIMEOUT);
restart_timer = 0;
}
/* If time for a keep alive message to be sent, transmission has been idle for keep_alive time */
client->cyclic_tick++;
if ((client->cyclic_tick * MQTT_CYCLIC_TIMER_INTERVAL) >= client->keep_alive) {
LWIP_DEBUGF(MQTT_DEBUG_TRACE, ("mqtt_cyclic_timer: Sending keep-alive message to server\n"));
if (mqtt_output_check_space(&client->output, 0) != 0) {
mqtt_output_append_fixed_header(&client->output, MQTT_MSG_TYPE_PINGREQ, 0, 0, 0, 0);
client->cyclic_tick = 0;
}
}
}
If the condition of the first if was true, mqtt_close() has been called. We can't enqueue a new keep-alive. So I propose to include the second block in an else statement:
if (client->keep_alive > 0) {
client->server_watchdog++;
/* If reception from server has been idle for 1.5*keep_alive time, server is considered unresponsive */
if ((client->server_watchdog * MQTT_CYCLIC_TIMER_INTERVAL) > (client->keep_alive + client->keep_alive / 2)) {
LWIP_DEBUGF(MQTT_DEBUG_WARN, ("mqtt_cyclic_timer: Server incoming keep-alive timeout\n"));
mqtt_close(client, MQTT_CONNECT_TIMEOUT);
restart_timer = 0;
} else {
/* If time for a keep alive message to be sent, transmission has been idle for keep_alive time */
client->cyclic_tick++;
if ((client->cyclic_tick * MQTT_CYCLIC_TIMER_INTERVAL) >= client->keep_alive) {
LWIP_DEBUGF(MQTT_DEBUG_TRACE, ("mqtt_cyclic_timer: Sending keep-alive message to server\n"));
if (mqtt_output_check_space(&client->output, 0) != 0) {
mqtt_output_append_fixed_header(&client->output, MQTT_MSG_TYPE_PINGREQ, 0, 0, 0, 0);
client->cyclic_tick = 0;
}
}
}
}