re-structure the OpenBSC directory layout

The new structure divides the code into a number of libraries
for the BSC core functionality, MSC core functionality, Abis transport,
TRAU and other bits.

This doesn't introduce any functional code change but simply moves
around files and alters Makefile.am accordingly.

Next step would be to disentangle a lot of the inter-library
dependencies and make the individual bits of code more independent.

1 files changed, 260 insertions, 0 deletions

diff --git a/openbsc/src/trau/trau_frame.c b/openbsc/src/trau/trau_frame.c
new file mode 100644
index 000000000..d4d6447cc
--- /dev/null
+++ b/openbsc/src/trau/trau_frame.c
@@ -0,0 +1,260 @@
+/* TRAU frame handling according to GSM TS 08.60 */
+
+/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <openbsc/trau_frame.h>
+#include <openbsc/subchan_demux.h>
+#include <openbsc/debug.h>
+
+static u_int32_t get_bits(const u_int8_t *bitbuf, int offset, int num)
+{
+	int i;
+	u_int32_t ret = 0;
+
+	for (i = offset; i < offset + num; i++) {
+		ret = ret << 1;
+		if (bitbuf[i])
+			ret |= 1;
+	}
+	return ret;
+}
+
+/* Decode according to 3.1.1 */
+static void decode_fr(struct decoded_trau_frame *fr, const u_int8_t *trau_bits)
+{
+	int i;
+	int d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits+0, trau_bits+17, 15);
+	/* C16 .. C21 */
+	memcpy(fr->c_bits+15, trau_bits+310, 6);
+	/* T1 .. T4 */
+	memcpy(fr->t_bits+0, trau_bits+316, 4);
+	/* D1 .. D255 */
+	for (i = 32; i < 304; i+= 16) {
+		memcpy(fr->d_bits + d_idx, trau_bits+i+1, 15);
+		d_idx += 15;
+	}
+	/* D256 .. D260 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 305, 5);
+}
+
+/* Decode according to 3.1.2 */
+static void decode_amr(struct decoded_trau_frame *fr, const u_int8_t *trau_bits)
+{
+	int i;
+	int d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits+0, trau_bits+17, 15);
+	/* C16 .. C25 */
+	memcpy(fr->c_bits+15, trau_bits+33, 10);
+	/* T1 .. T4 */
+	memcpy(fr->t_bits+0, trau_bits+316, 4);
+	/* D1 .. D5 */
+	memcpy(fr->d_bits, trau_bits+43, 5);
+	/* D6 .. D245 */
+	for (i = 48; i < 304; i += 16) {
+		memcpy(fr->d_bits + d_idx, trau_bits+i+1, 15);
+		d_idx += 15;
+	}
+	/* D246 .. D256 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 305, 11);
+}
+
+int decode_trau_frame(struct decoded_trau_frame *fr, const u_int8_t *trau_bits)
+{
+	u_int8_t cbits5 = get_bits(trau_bits, 17, 5);
+
+	switch (cbits5) {
+	case TRAU_FT_FR_UP:
+	case TRAU_FT_FR_DOWN:
+	case TRAU_FT_IDLE_UP:
+	case TRAU_FT_IDLE_DOWN:
+	case TRAU_FT_EFR:
+		decode_fr(fr, trau_bits);
+		break;
+	case TRAU_FT_AMR:
+		decode_amr(fr, trau_bits);
+		break;
+	case TRAU_FT_OM_UP:
+	case TRAU_FT_OM_DOWN:
+	case TRAU_FT_DATA_UP:
+	case TRAU_FT_DATA_DOWN:
+	case TRAU_FT_D145_SYNC:
+	case TRAU_FT_EDATA:
+		LOGP(DMUX, LOGL_NOTICE, "can't decode unimplemented TRAU "
+			"Frame Type 0x%02x\n", cbits5);
+		return -1;
+		break;
+	default:
+		LOGP(DMUX, LOGL_NOTICE, "can't decode unknown TRAU "
+			"Frame Type 0x%02x\n", cbits5);
+		return -1;
+		break;
+	}
+
+	return 0;
+}
+
+const u_int8_t ft_fr_down_bits[] = { 1, 1, 1, 0, 0 };
+const u_int8_t ft_idle_down_bits[] = { 0, 1, 1, 1, 0 };
+
+/* modify an uplink TRAU frame so we can send it downlink */
+int trau_frame_up2down(struct decoded_trau_frame *fr)
+{
+	u_int8_t cbits5 = get_bits(fr->c_bits, 0, 5);
+
+	switch (cbits5) {
+	case TRAU_FT_FR_UP:
+		memcpy(fr->c_bits, ft_fr_down_bits, 5);
+		/* clear time alignment */
+		memset(fr->c_bits+5, 0, 6);
+		/* FIXME: SP / BFI in case of DTx */
+		/* C12 .. C21 are spare and coded as '1' */
+		memset(fr->c_bits+11, 0x01, 10);
+		break;
+	case TRAU_FT_EFR:
+		/* clear time alignment */
+		memset(fr->c_bits+5, 0, 6);
+		/* FIXME: set UFE appropriately */
+		/* FIXME: SP / BFI in case of DTx */
+		break;
+	case TRAU_FT_IDLE_UP:
+		memcpy(fr->c_bits, ft_idle_down_bits, 5);
+		/* clear time alignment */
+		memset(fr->c_bits+5, 0, 6);
+		/* FIXME: SP / BFI in case of DTx */
+		/* C12 .. C21 are spare and coded as '1' */
+		memset(fr->c_bits+11, 0x01, 10);
+		break;
+	case TRAU_FT_FR_DOWN:
+	case TRAU_FT_IDLE_DOWN:
+	case TRAU_FT_OM_DOWN:
+	case TRAU_FT_DATA_DOWN:
+		/* we cannot convert a downlink to a downlink frame */
+		return -EINVAL;
+		break;
+	case TRAU_FT_AMR:
+	case TRAU_FT_OM_UP:
+	case TRAU_FT_DATA_UP:
+	case TRAU_FT_D145_SYNC:
+	case TRAU_FT_EDATA:
+		LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type "
+			"0x%02x\n", cbits5);
+		return -1;
+		break;
+	default:
+		LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type "
+			"0x%02x\n", cbits5);
+		return -1;
+		break;
+	}
+
+	return 0;
+
+}
+
+static void encode_fr(u_int8_t *trau_bits, const struct decoded_trau_frame *fr)
+{
+	int i;
+	int d_idx = 0;
+
+	trau_bits[16] = 1;
+	/* C1 .. C15 */
+	memcpy(trau_bits+17, fr->c_bits+0, 15);
+	/* D1 .. D255 */
+	for (i = 32; i < 304; i+= 16) {
+		trau_bits[i] = 1;
+		memcpy(trau_bits+i+1, fr->d_bits + d_idx, 15);
+		d_idx += 15;
+	}
+	/* D256 .. D260 */
+	trau_bits[304] = 1;
+	memcpy(trau_bits + 305, fr->d_bits + d_idx, 5);
+	/* C16 .. C21 */
+	memcpy(trau_bits+310, fr->c_bits+15, 6);
+
+	/* FIXME: handle timing adjustment */
+
+	/* T1 .. T4 */
+	memcpy(trau_bits+316, fr->t_bits+0, 4);
+}
+
+
+int encode_trau_frame(u_int8_t *trau_bits, const struct decoded_trau_frame *fr)
+{
+	u_int8_t cbits5 = get_bits(fr->c_bits, 0, 5);
+	
+	/* 16 bits of sync header */
+	memset(trau_bits, 0, 16);
+
+	switch (cbits5) {
+	case TRAU_FT_FR_UP:
+	case TRAU_FT_FR_DOWN:
+	case TRAU_FT_IDLE_UP:
+	case TRAU_FT_IDLE_DOWN:
+	case TRAU_FT_EFR:
+		encode_fr(trau_bits, fr);
+		break;
+	case TRAU_FT_AMR:
+	case TRAU_FT_OM_UP:
+	case TRAU_FT_OM_DOWN:
+	case TRAU_FT_DATA_UP:
+	case TRAU_FT_DATA_DOWN:
+	case TRAU_FT_D145_SYNC:
+	case TRAU_FT_EDATA:
+		LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type "
+			"0x%02x\n", cbits5);
+		return -1;
+		break;
+	default:
+		LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type "
+			"0x%02x\n", cbits5);
+		return -1;
+		break;
+	}
+
+	return 0;
+}
+
+static struct decoded_trau_frame fr_idle_frame = {
+	.c_bits = { 0, 1, 1, 1, 0 },	/* IDLE DOWNLINK 3.5.5 */
+	.t_bits = { 1, 1, 1, 1 },
+};
+static u_int8_t encoded_idle_frame[TRAU_FRAME_BITS];
+static int dbits_initted;
+
+u_int8_t *trau_idle_frame(void)
+{
+	/* only initialize during the first call */
+	if (!dbits_initted) {
+		/* set all D-bits to 1 */
+		memset(&fr_idle_frame.d_bits, 0x01, 260);
+		encode_fr(encoded_idle_frame, &fr_idle_frame);
+	}
+	return encoded_idle_frame;
+}