freetdm: Added release guard time configuration

Currently only enabled in the analog e&m module but any
signaling module can easily take advantage of it with a small
modification to the signaling module to set span->sig_release_guard_time_ms

libs/freetdm/mod_freetdm/mod_freetdm.c

@@ -566,7 +566,7 @@ static switch_status_t channel_on_hangup(switch_core_session_t *session)
 	}
 
 	if (!uuid_found) {
-		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Device [%d:%d] is no longer attached to %s. Nothing to do.\n", span_id, chan_id, name);
+		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Device [%d:%d] is no longer attached to %s\n", span_id, chan_id, name);
 		goto end;
 	}
 
@@ -3827,6 +3827,7 @@ static switch_status_t load_config(void)
 			const char *tonegroup = NULL;
 			char *digit_timeout = NULL;
 			char *dial_timeout = NULL;
+			char *release_guard_time_ms = NULL;
 			char *max_digits = NULL;
 			char *dial_regex = NULL;
 			char *hold_music = NULL;
@@ -3836,7 +3837,7 @@ static switch_status_t load_config(void)
 			char *answer_supervision = str_false;
 			char *immediate_ringback = str_false;
 			char *ringback_file = str_empty;
-			uint32_t span_id = 0, to = 0, max = 0, dial_timeout_int = 0;
+			uint32_t span_id = 0, to = 0, max = 0, dial_timeout_int = 0, release_guard_time_ms_int = 0;
 			ftdm_span_t *span = NULL;
 			analog_option_t analog_options = ANALOG_OPTION_NONE;
 
@@ -3850,6 +3851,8 @@ static switch_status_t load_config(void)
 					digit_timeout = val;
 				} else if (!strcasecmp(var, "dial-timeout")) {
 					dial_timeout = val;
+				} else if (!strcasecmp(var, "release-guard-time-ms")) {
+					release_guard_time_ms = val;
 				} else if (!strcasecmp(var, "context")) {
 					context = val;
 				} else if (!strcasecmp(var, "dialplan")) {
@@ -3890,6 +3893,10 @@ static switch_status_t load_config(void)
 				dial_timeout_int = atoi(dial_timeout);
 			}
 
+			if (release_guard_time_ms) {
+				release_guard_time_ms_int = atoi(release_guard_time_ms);
+			}
+
 			if (max_digits) {
 				max = atoi(max_digits);
 			}
@@ -3925,6 +3932,7 @@ static switch_status_t load_config(void)
 								   "ringback_file", ringback_file,
 								   "digit_timeout", &to,
 								   "dial_timeout", &dial_timeout_int,
+								   "release_guard_time_ms", &release_guard_time_ms_int,
 								   "max_dialstr", &max,
 								   FTDM_TAG_END) != FTDM_SUCCESS) {
 				LOAD_ERROR("Error starting FreeTDM span %d\n", span_id);

libs/freetdm/src/ftdm_io.c

@@ -1490,6 +1490,15 @@ static __inline__ int chan_is_avail(ftdm_channel_t *check)
 			return 0;
 		}
 	}
+	/* release guard time check */
+	if (check->span->sig_release_guard_time_ms && check->last_release_time) {
+		ftdm_time_t time_diff = (check->last_release_time - ftdm_current_time_in_ms());
+		if (time_diff < check->span->sig_release_guard_time_ms) {
+			return 0;
+		}
+		/* circuit now available for outbound dialing */
+		check->last_release_time = 0;
+	}
 	return 1;
 }
 
@@ -2982,6 +2991,11 @@ static ftdm_status_t ftdm_channel_done(ftdm_channel_t *ftdmchan)
 		ftdmchan->packet_len = ftdmchan->native_interval * (ftdmchan->effective_codec == FTDM_CODEC_SLIN ? 16 : 8);
 		ftdm_clear_flag(ftdmchan, FTDM_CHANNEL_TRANSCODE);
 	}
+
+	if (ftdmchan->span->sig_release_guard_time_ms) {
+		ftdmchan->last_release_time = ftdm_current_time_in_ms();
+	}
+
 	ftdm_log_chan_msg(ftdmchan, FTDM_LOG_DEBUG, "channel done\n");
 	return FTDM_SUCCESS;
 }

libs/freetdm/src/ftmod/ftmod_analog_em/ftmod_analog_em.c

@@ -378,6 +378,7 @@ static FIO_SIG_CONFIGURE_FUNCTION(ftdm_analog_em_configure_span)
 	uint32_t digit_timeout = 2000;
 	uint32_t max_dialstr = 11;
 	uint32_t dial_timeout = 0;
+	uint32_t release_guard_time_ms = 500;
 	ftdm_bool_t answer_supervision = FTDM_FALSE;
 	const char *var, *val;
 	int *intval;
@@ -429,6 +430,11 @@ static FIO_SIG_CONFIGURE_FUNCTION(ftdm_analog_em_configure_span)
 				break;
 			}
 			max_dialstr = *intval;
+		} else if (!strcasecmp(var, "release_guard_time_ms")) {
+			if (!(intval = va_arg(ap, int *))) {
+				break;
+			}
+			release_guard_time_ms = *intval;
 		} else {
 			ftdm_log(FTDM_LOG_ERROR, "Invalid parameter for analog em span: '%s'\n", var);
 			return FTDM_FAIL;
@@ -460,6 +466,7 @@ static FIO_SIG_CONFIGURE_FUNCTION(ftdm_analog_em_configure_span)
 	span->get_span_sig_status = analog_em_get_span_sig_status;
 	span->set_channel_sig_status = analog_em_set_channel_sig_status;
 	span->set_span_sig_status = analog_em_set_span_sig_status;
+	span->sig_release_guard_time_ms = release_guard_time_ms;
 	ftdm_span_load_tones(span, tonemap);
 	if (immediate_ringback || !ftdm_strlen_zero(ringback_file)) {
 		analog_data->immediate_ringback = FTDM_TRUE;

libs/freetdm/src/include/private/ftdm_core.h

@@ -477,6 +477,7 @@ struct ftdm_channel {
 	int32_t rxdrops;
 	ftdm_usrmsg_t *usrmsg;
 	ftdm_time_t last_state_change_time;
+	ftdm_time_t last_release_time;
 };
 
 struct ftdm_span {
@@ -514,6 +515,7 @@ struct ftdm_span {
 	ftdm_channel_sig_read_t sig_read;
 	ftdm_channel_sig_write_t sig_write;
 	ftdm_channel_sig_dtmf_t sig_dtmf;
+	uint32_t sig_release_guard_time_ms;
 	ftdm_channel_state_processor_t state_processor; /*!< This guy is called whenever state processing is required */
 	void *io_data; /*!< Private I/O data per span. Do not touch unless you are an I/O module */
 	char *type;