ftmod_libpri: Add experimental (untested) support for overlap receiving in TE mode.

Adds a new "overlapdial" configuration parameter that enables
incoming overlap dialing when set to "incoming", "yes" or "both" (possible values:
"no", "yes"/"both", "incoming"/"receive", "outgoing"/"send").

(Overlap dialing is disabled by default)

NOTE: only the non-overlap receive case has been tested (= doesn't break existing setups)

Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.h

@@ -51,6 +51,12 @@ typedef enum {
 	FTMOD_LIBPRI_RUNNING = (1 << 0)
 } ftdm_isdn_flag_t;
 
+typedef enum {
+	FTMOD_LIBPRI_OVERLAP_NONE    = 0,
+	FTMOD_LIBPRI_OVERLAP_RECEIVE = (1 << 0),
+	FTMOD_LIBPRI_OVERLAP_SEND    = (1 << 1)
+#define FTMOD_LIBPRI_OVERLAP_BOTH	(FTMOD_LIBPRI_OVERLAP_RECEIVE | FTMOD_LIBPRI_OVERLAP_SEND)
+} ftdm_isdn_overlap_t;
 
 struct ftdm_libpri_data {
 	ftdm_channel_t *dchan;
@@ -60,6 +66,7 @@ struct ftdm_libpri_data {
 
 	int mode;
 	int dialect;
+	int overlap;		/*!< Overlap dial flags */
 	unsigned int layer1;
 	unsigned int ton;