Register recall signal is now handled correctly

Active call will be put on hold.
During dialing, active call will be retrieved.

This also applies to on-hook pulse, if it is used by AN. (No AN I have
seen uses this pulse.)

src/pstn/pstn.c

@@ -1546,9 +1546,20 @@ static void v5_sig_ind(pstn_t *pstn, uint8_t *data, int len)
 		break;
 	case PSTN_V5_IE_PULSED_SIGNAL:
 		switch ((data[2] & 0x7f)) {
+		case PSTN_V5_PULSED_SIGNAL_REG_RECAL:
+			PDEBUG(DTEL, DEBUG_INFO, "Received register recall signal.\n");
+			if (pstn->recall && (pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_ACTIVE
+					  || pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_ENBLOCK
+					  || pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_OVERLAP_NET)) {
+				PDEBUG(DTEL, DEBUG_INFO, "Performing hookflash, register recall signal was received.\n");
+				hookflash(pstn);
+			}
+			break;
 		case PSTN_V5_PULSED_SIGNAL_ON_HOOK:
 			PDEBUG(DTEL, DEBUG_INFO, "Received pulsed on-kook signal.\n");
-			if (pstn->recall && pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_ACTIVE) {
+			if (pstn->recall && (pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_ACTIVE
+					  || pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_ENBLOCK
+					  || pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_OVERLAP_NET)) {
 				PDEBUG(DTEL, DEBUG_INFO, "Performing hookflash, on-hook pulse was received.\n");
 				hookflash(pstn);
 			}

src/pstn/pstn.h

@@ -46,6 +46,7 @@ enum pstn_v5_signal {
 	PSTN_V5_STEADY_SIGNAL_ON_HOOK	= 0x05,
 	PSTN_V5_STEADY_SIGNAL_STOP_RING	= 0x0e,
 	PSTN_V5_PULSED_SIGNAL_INIT_RING	= 0x79,
+	PSTN_V5_PULSED_SIGNAL_REG_RECAL	= 0x76,
 	PSTN_V5_PULSED_SIGNAL_ON_HOOK	= 0x7c,
 };