RTP-enable MNCC API for LCR + ip.access

Instead of passing TRAU frames down the MNCC API to the call control
application like MNCC, we now decode the TRAU frame into the actual codec
frame.  We do the same with the RTP packets in case of ip.access and
thus have a unified format of passing codec data from the BTS to
an application, independent of the BTS type.

This is only implemented for V1 full-rate at the moment, and needs
to be fixed.

1 files changed, 83 insertions, 9 deletions

diff --git a/openbsc/src/trau_mux.c b/openbsc/src/trau_mux.c
index 7ea65ce35..477ea21e5 100644
--- a/openbsc/src/trau_mux.c
+++ b/openbsc/src/trau_mux.c
@@ -32,6 +32,19 @@
 #include <openbsc/debug.h>
 #include <openbsc/talloc.h>
 
+u_int8_t gsm_fr_map[] = {
+	6, 6, 5, 5, 4, 4, 3, 3,
+	7, 2, 2, 6, 3, 3, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3,
+	3, 7, 2, 2, 6, 3, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 7, 2, 2, 6, 3, 3,
+	3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 3, 7, 2, 2, 6, 3,
+	3, 3, 3, 3, 3, 3, 3, 3,
+	3, 3, 3, 3
+};
+
 struct map_entry {
 	struct llist_head list;
 	struct gsm_e1_subslot src, dst;
@@ -144,6 +157,8 @@ lookup_trau_upqueue(const struct gsm_e1_subslot *src)
 	return NULL;
 }
 
+static const u_int8_t c_bits_check[] = { 0, 0, 0, 1, 0 };
+
 /* we get called by subchan_demux */
 int trau_mux_input(struct gsm_e1_subslot *src_e1_ss,
 		   const u_int8_t *trau_bits, int num_bits)
@@ -153,8 +168,6 @@ int trau_mux_input(struct gsm_e1_subslot *src_e1_ss,
 	struct gsm_e1_subslot *dst_e1_ss = lookup_trau_mux_map(src_e1_ss);
 	struct subch_mux *mx;
 	struct upqueue_entry *ue;
-	struct msgb *msg;
-	struct gsm_trau_frame *frame;
 	int rc;
 
 	/* decode TRAU, change it to downlink, re-encode */
@@ -163,19 +176,44 @@ int trau_mux_input(struct gsm_e1_subslot *src_e1_ss,
 		return rc;
 
 	if (!dst_e1_ss) {
+		struct msgb *msg;
+		struct gsm_data_frame *frame;
+		unsigned char *data;
+		int i, j, k, l, o;
 		/* frame shall be sent to upqueue */
 		if (!(ue = lookup_trau_upqueue(src_e1_ss)))
 			return -EINVAL;
 		if (!ue->callref)
 			return -EINVAL;
-		msg = msgb_alloc(sizeof(struct gsm_trau_frame) + sizeof(tf),
-				 "TRAU");
+		if (memcpy(tf.c_bits, c_bits_check, sizeof(c_bits_check)))
+			DEBUGPC(DMUX, "illegal trau (C1-C5) %s\n",
+				hexdump(tf.c_bits, sizeof(c_bits_check)));
+		msg = msgb_alloc(sizeof(struct gsm_data_frame) + 33,
+				 "GSM-DATA");
 		if (!msg)
 			return -ENOMEM;
-		frame = (struct gsm_trau_frame *)msg->data;
-		frame->msg_type = GSM_TRAU_FRAME;
+
+		frame = (struct gsm_data_frame *)msg->data;
+		memset(frame, 0, sizeof(struct gsm_data_frame));
+		data = frame->data;
+		data[0] = 0xd << 4;
+		/* reassemble d-bits */
+		i = 0; /* counts bits */
+		j = 4; /* counts output bits */
+		k = gsm_fr_map[0]-1; /* current number bit in element */
+		l = 0; /* counts element bits */
+		o = 0; /* offset input bits */
+		while (i < 260) {
+			data[j/8] |= (tf.d_bits[k+o] << (7-(j%8)));
+			if (--k < 0) {
+				o += gsm_fr_map[l];
+				k = gsm_fr_map[++l]-1;
+			}
+			i++;
+			j++;
+		}
+		frame->msg_type = GSM_TCHF_FRAME;
 		frame->callref = ue->callref;
-		memcpy(frame->data, &tf, sizeof(tf));
 		msgb_enqueue(&ue->net->upqueue, msg);
 
 		return 0;
@@ -221,17 +259,53 @@ int trau_recv_lchan(struct gsm_lchan *lchan, u_int32_t callref)
 	return 0;
 }
 
-int trau_send_lchan(struct gsm_lchan *lchan, struct decoded_trau_frame *tf)
+int trau_send_frame(struct gsm_lchan *lchan, struct gsm_data_frame *frame)
 {
 	u_int8_t trau_bits_out[TRAU_FRAME_BITS];
 	struct gsm_e1_subslot *dst_e1_ss = &lchan->ts->e1_link;
 	struct subch_mux *mx;
+	int i, j, k, l, o;
+	unsigned char *data = frame->data;
+	struct decoded_trau_frame tf;
 
 	mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts);
 	if (!mx)
 		return -EINVAL;
 
-	encode_trau_frame(trau_bits_out, tf);
+	switch (frame->msg_type) {
+	case GSM_TCHF_FRAME:
+		/* set c-bits and t-bits */
+		tf.c_bits[0] = 1;
+		tf.c_bits[1] = 1;
+		tf.c_bits[2] = 1;
+		tf.c_bits[3] = 0;
+		tf.c_bits[4] = 0;
+		memset(&tf.c_bits[5], 0, 6);
+		memset(&tf.c_bits[11], 1, 10);
+		memset(&tf.t_bits[0], 1, 4);
+		/* reassemble d-bits */
+		i = 0; /* counts bits */
+		j = 4; /* counts input bits */
+		k = gsm_fr_map[0]-1; /* current number bit in element */
+		l = 0; /* counts element bits */
+		o = 0; /* offset output bits */
+		while (i < 260) {
+			tf.d_bits[k+o] = (data[j/8] >> (7-(j%8))) & 1;
+			if (--k < 0) {
+				o += gsm_fr_map[l];
+				k = gsm_fr_map[++l]-1;
+			}
+			i++;
+			j++;
+		}
+		break;
+	default:
+		DEBUGPC(DMUX, "unsupported message type %d\n",
+			frame->msg_type);
+		return -EINVAL;
+	}
+
+	encode_trau_frame(trau_bits_out, &tf);
 
 	/* and send it to the muxer */
 	return subchan_mux_enqueue(mx, dst_e1_ss->e1_ts_ss, trau_bits_out,