l1ctl_proto.h: use flexible array member for traffic messages

Unlike the DATA messages, traffic frames may have different length.
Instead of having fixed payload (i.e. TCH frame) length, let's
introduce a flexible array member. This would allow one to
calculate the frame length using the MSGB API.

Change-Id: I119fa36c84e95c3003d57c19e25f8146ed45c3c6

4 files changed, 33 insertions, 20 deletions

diff --git a/include/l1ctl_proto.h b/include/l1ctl_proto.h
index f1bff860..c6156f5a 100644
--- a/include/l1ctl_proto.h
+++ b/include/l1ctl_proto.h
@@ -96,8 +96,6 @@ enum l1ctl_coding_scheme {
 	L1CTL_MCS9,
 };
 
-#define TRAFFIC_DATA_LEN	40
-
 /*
  * NOTE: struct size. We do add manual padding out of the believe
  * that it will avoid some unaligned access.
@@ -162,7 +160,7 @@ struct l1ctl_data_ind {
 
 /* traffic from the network */
 struct l1ctl_traffic_ind {
-	uint8_t data[TRAFFIC_DATA_LEN];
+	uint8_t data[0];
 } __attribute__((packed));
 
 /*
@@ -346,7 +344,7 @@ struct l1ctl_neigh_pm_ind {
 
 /* traffic data to network */
 struct l1ctl_traffic_req {
-	uint8_t data[TRAFFIC_DATA_LEN];
+	uint8_t data[0];
 } __attribute__((packed));
 
 struct l1ctl_tbf_cfg_req {
diff --git a/src/host/layer23/src/common/l1ctl.c b/src/host/layer23/src/common/l1ctl.c
index 96db52fb..5d6d9c0c 100644
--- a/src/host/layer23/src/common/l1ctl.c
+++ b/src/host/layer23/src/common/l1ctl.c
@@ -762,6 +762,8 @@ static int rx_l1_traffic_ind(struct osmocom_ms *ms, struct msgb *msg)
 {
 	struct l1ctl_info_dl *dl;
 	struct l1ctl_traffic_ind *ti;
+	size_t frame_len;
+	uint8_t *frame;
 
 	if (msgb_l1len(msg) < sizeof(*dl)) {
 		LOGP(DL1C, LOGL_ERROR, "TRAFFIC IND MSG too short "
@@ -771,10 +773,17 @@ static int rx_l1_traffic_ind(struct osmocom_ms *ms, struct msgb *msg)
 
 	/* Header handling */
 	dl = (struct l1ctl_info_dl *) msg->l1h;
+	ti = (struct l1ctl_traffic_ind *) dl->payload;
+	frame = (uint8_t *) ti->data;
+
 	msg->l2h = dl->payload;
-	ti = (struct l1ctl_traffic_ind *) msg->l2h;
+	msg->l3h = frame;
+
+	/* Calculate the frame length */
+	frame_len = msgb_l3len(msg);
 
-	DEBUGP(DL1C, "TRAFFIC IND (%s)\n", osmo_hexdump(ti->data, 33));
+	DEBUGP(DL1C, "TRAFFIC IND len=%zu (%s)\n", frame_len,
+		osmo_hexdump(frame, frame_len));
 
 	/* distribute or drop */
 	if (ms->l1_entity.l1_traffic_ind)
@@ -791,28 +800,28 @@ int l1ctl_tx_traffic_req(struct osmocom_ms *ms, struct msgb *msg,
 	struct l1ctl_hdr *l1h;
 	struct l1ctl_info_ul *l1i_ul;
 	struct l1ctl_traffic_req *tr;
+	size_t frame_len;
+	uint8_t *frame;
 
 	/* Header handling */
 	tr = (struct l1ctl_traffic_req *) msg->l2h;
+	frame = (uint8_t *) tr->data;
+	msg->l3h = frame;
 
-	DEBUGP(DL1C, "TRAFFIC REQ (%s)\n",
-		osmo_hexdump(msg->l2h, msgb_l2len(msg)));
+	/* Calculate the frame length */
+	frame_len = msgb_l3len(msg);
 
-	if (msgb_l2len(msg) != 33) {
-		LOGP(DL1C, LOGL_ERROR, "Traffic Request has incorrect length "
-			"(%u != 33)\n", msgb_l2len(msg));
-		msgb_free(msg);
-		return -EINVAL;
-	}
+	DEBUGP(DL1C, "TRAFFIC REQ len=%zu (%s)\n", frame_len,
+		osmo_hexdump(frame, frame_len));
 
-	if ((tr->data[0] >> 4) != 0xd) {
+	if ((frame[0] >> 4) != 0xd) {
 		LOGP(DL1C, LOGL_ERROR, "Traffic Request has incorrect magic "
-			"(%u != 0xd)\n", tr->data[0] >> 4);
+			"(%u != 0xd)\n", frame[0] >> 4);
 		msgb_free(msg);
 		return -EINVAL;
 	}
 
-//	printf("TX %s\n", osmo_hexdump(tr->data, 33));
+//	printf("TX %s\n", osmo_hexdump(frame, frame_len));
 
 	/* prepend uplink info header */
 	l1i_ul = (struct l1ctl_info_ul *) msgb_push(msg, sizeof(*l1i_ul));
diff --git a/src/host/virt_phy/src/virt_prim_traffic.c b/src/host/virt_phy/src/virt_prim_traffic.c
index 4e58de60..5f6b273b 100644
--- a/src/host/virt_phy/src/virt_prim_traffic.c
+++ b/src/host/virt_phy/src/virt_prim_traffic.c
@@ -84,6 +84,7 @@ void l1ctl_tx_traffic_ind(struct l1_model_ms *ms, struct msgb *msg, uint16_t arf
 	struct msgb *l1ctl_msg = NULL;
 	struct l1ctl_traffic_ind * l1ti;
 	struct l1ctl_info_dl * l1dl;
+	uint8_t *frame, frame_len;
 	uint8_t rsl_chan_type, subchan, timeslot;
 	l1ctl_msg = l1ctl_msgb_alloc(L1CTL_TRAFFIC_IND);
 	l1dl = (struct l1ctl_info_dl *) msgb_put(l1ctl_msg, sizeof(*l1dl));
@@ -102,7 +103,10 @@ void l1ctl_tx_traffic_ind(struct l1_model_ms *ms, struct msgb *msg, uint16_t arf
 
 	/* TODO: traffic decoding and decryption */
 
-	memcpy(l1ti->data, msgb_data(msg), msgb_length(msg));
+	frame_len = msgb_length(msg);
+	frame = (uint8_t *) msgb_put(l1ctl_msg, frame_len);
+	memcpy(frame, msgb_data(msg), frame_len);
+
 	DEBUGPMS(DL1P, ms, "Tx L1CTL_TRAFFIC_IND (chan_nr=0x%02x, link_id=0x%02x)\n", chan_nr, link_id);
 	l1ctl_sap_tx_to_l23_inst(ms, l1ctl_msg);
 }
diff --git a/src/target/firmware/layer1/prim_tch.c b/src/target/firmware/layer1/prim_tch.c
index 2dadaaf4..a8036d2f 100644
--- a/src/target/firmware/layer1/prim_tch.c
+++ b/src/target/firmware/layer1/prim_tch.c
@@ -338,6 +338,7 @@ static int l1s_tch_resp(__unused uint8_t p1, __unused uint8_t p2, uint16_t p3)
 				struct msgb *msg;
 				struct l1ctl_info_dl *dl;
 				struct l1ctl_traffic_ind *ti;
+				uint8_t *payload;
 
 				/* Allocate msgb */
 				/* FIXME: we actually want all allocation out of L1S! */
@@ -349,15 +350,16 @@ static int l1s_tch_resp(__unused uint8_t p1, __unused uint8_t p2, uint16_t p3)
 
 				dl = (struct l1ctl_info_dl *) msgb_put(msg, sizeof(*dl));
 				ti = (struct l1ctl_traffic_ind *) msgb_put(msg, sizeof(*ti));
+				payload = (uint8_t *) msgb_put(msg, 33);
 
 				/* Copy actual data, skipping the information block [0,1,2] */
-				dsp_memcpy_from_api(ti->data, &traffic_buf[3], 33, 1);
+				dsp_memcpy_from_api(payload, &traffic_buf[3], 33, 1);
 
 				/**
 				 * Perform some bit conversations
 				 * FIXME: what about other (than FR) codecs?
 				 */
-				tch_fr_bit_magic(ti, 1);
+				tch_fr_bit_magic(payload, 1);
 
 				/* Give message to up layer */
 				l1_queue_for_l2(msg);