read channel ID to reply on the same channel

examples/simple/datagram/thr_example2.c

@@ -40,8 +40,8 @@ static int encode(int argc, char *argv[]) {
   else
   {
     p_thr_chn = thr_open_chn(dest_mac, chn_id, frag_size, freq,NULL);
-    p_thr_chn2 = thr_open_chn(dest_mac, 17, frag_size, 100,(thr_msg_handler_t)labcomm_decoder_decode_one);
-    encoder = labcomm_encoder_new(labcomm_thr_writer, p_thr_chn);
+    p_thr_chn2 = thr_open_chn(dest_mac, chn_id, frag_size, freq,(thr_msg_handler_t)labcomm_decoder_decode_one);
+    encoder = labcomm_encoder_new(labcomm_thr_writer, p_thr_chn2);
     labcomm_encoder_register_simple_TwoInts(encoder);
     labcomm_encoder_register_simple_IntString(encoder);
     decoder = labcomm_decoder_new(labcomm_thr_reader, p_thr_chn2);
@@ -79,9 +79,10 @@ static int encode(int argc, char *argv[]) {
 
 static void handle_simple_TwoInts(simple_TwoInts *v,void *context) {
   unsigned char *src = get_sender_addr((struct thr_chn_t *)context); 
+  unsigned char ch_id = get_channel((struct thr_chn_t *)context); 
   printf("Got TwoInts. a=%d, b=%d\n", v->a, v->b);
   printf("... src addr: %x:%x:%x:%x:%x:%x\n", src[0],  src[1], src[2], src[3], src[4], src[5]);
-  struct thr_chan_t *ch = thr_open_chn(src, 17, (unsigned short)50, (unsigned short)100, NULL);
+  struct thr_chan_t *ch = thr_open_chn(src, ch_id, (unsigned short)50, (unsigned short)100, NULL);
   struct labcomm_encoder *enc = labcomm_encoder_new(labcomm_thr_writer, ch);
   labcomm_encoder_register_simple_TwoInts(enc);
   v->a *= 2;

lib/c/experimental/ThrottleDrv/throttle_drv.c

@@ -404,3 +404,7 @@ int thr_read(struct thr_chn_t* thr_chn, unsigned char* data, int length)
 unsigned char* get_sender_addr(struct thr_chn_t* ch) {
 	return ch->last_sender_adr;
 }
+
+unsigned char get_channel(struct thr_chn_t* ch) {
+	return ch->id;
+}

lib/c/experimental/ThrottleDrv/throttle_drv.h

@@ -16,4 +16,5 @@ int thr_send(const struct thr_chn_t* thr_chn, const char* data, unsigned int len
 int thr_read(struct thr_chn_t* thr_chn, unsigned char* data, int length);
 
 unsigned char* get_sender_addr(struct thr_chn_t* ch);
+unsigned char get_channel(struct thr_chn_t* ch);
 #endif