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-rw-r--r--src/libtrau/trau_mux.c312
1 files changed, 312 insertions, 0 deletions
diff --git a/src/libtrau/trau_mux.c b/src/libtrau/trau_mux.c
new file mode 100644
index 00000000..712e22d8
--- /dev/null
+++ b/src/libtrau/trau_mux.c
@@ -0,0 +1,312 @@
+/* Simple TRAU frame reflector to route voice calls */
+
+/* (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 <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/trau_frame.h>
+#include <openbsc/trau_mux.h>
+#include <openbsc/subchan_demux.h>
+#include <openbsc/e1_input.h>
+#include <openbsc/debug.h>
+#include <osmocore/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;
+};
+
+struct upqueue_entry {
+ struct llist_head list;
+ struct gsm_network *net;
+ struct gsm_e1_subslot src;
+ u_int32_t callref;
+};
+
+static LLIST_HEAD(ss_map);
+static LLIST_HEAD(ss_upqueue);
+
+void *tall_map_ctx, *tall_upq_ctx;
+
+/* map one particular subslot to another subslot */
+int trau_mux_map(const struct gsm_e1_subslot *src,
+ const struct gsm_e1_subslot *dst)
+{
+ struct map_entry *me;
+
+ me = talloc(tall_map_ctx, struct map_entry);
+ if (!me) {
+ LOGP(DMIB, LOGL_FATAL, "Out of memory\n");
+ return -ENOMEM;
+ }
+
+ DEBUGP(DCC, "Setting up TRAU mux map between (e1=%u,ts=%u,ss=%u) "
+ "and (e1=%u,ts=%u,ss=%u)\n",
+ src->e1_nr, src->e1_ts, src->e1_ts_ss,
+ dst->e1_nr, dst->e1_ts, dst->e1_ts_ss);
+
+ /* make sure to get rid of any stale old mappings */
+ trau_mux_unmap(src, 0);
+ trau_mux_unmap(dst, 0);
+
+ memcpy(&me->src, src, sizeof(me->src));
+ memcpy(&me->dst, dst, sizeof(me->dst));
+ llist_add(&me->list, &ss_map);
+
+ return 0;
+}
+
+int trau_mux_map_lchan(const struct gsm_lchan *src,
+ const struct gsm_lchan *dst)
+{
+ struct gsm_e1_subslot *src_ss, *dst_ss;
+
+ src_ss = &src->ts->e1_link;
+ dst_ss = &dst->ts->e1_link;
+
+ return trau_mux_map(src_ss, dst_ss);
+}
+
+
+/* unmap one particular subslot from another subslot */
+int trau_mux_unmap(const struct gsm_e1_subslot *ss, u_int32_t callref)
+{
+ struct map_entry *me, *me2;
+ struct upqueue_entry *ue, *ue2;
+
+ if (ss)
+ llist_for_each_entry_safe(me, me2, &ss_map, list) {
+ if (!memcmp(&me->src, ss, sizeof(*ss)) ||
+ !memcmp(&me->dst, ss, sizeof(*ss))) {
+ llist_del(&me->list);
+ return 0;
+ }
+ }
+ llist_for_each_entry_safe(ue, ue2, &ss_upqueue, list) {
+ if (ue->callref == callref) {
+ llist_del(&ue->list);
+ return 0;
+ }
+ if (ss && !memcmp(&ue->src, ss, sizeof(*ss))) {
+ llist_del(&ue->list);
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+
+/* look-up an enty in the TRAU mux map */
+static struct gsm_e1_subslot *
+lookup_trau_mux_map(const struct gsm_e1_subslot *src)
+{
+ struct map_entry *me;
+
+ llist_for_each_entry(me, &ss_map, list) {
+ if (!memcmp(&me->src, src, sizeof(*src)))
+ return &me->dst;
+ if (!memcmp(&me->dst, src, sizeof(*src)))
+ return &me->src;
+ }
+ return NULL;
+}
+
+/* look-up an enty in the TRAU upqueue */
+struct upqueue_entry *
+lookup_trau_upqueue(const struct gsm_e1_subslot *src)
+{
+ struct upqueue_entry *ue;
+
+ llist_for_each_entry(ue, &ss_upqueue, list) {
+ if (!memcmp(&ue->src, src, sizeof(*src)))
+ return ue;
+ }
+ 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)
+{
+ struct decoded_trau_frame tf;
+ u_int8_t trau_bits_out[TRAU_FRAME_BITS];
+ struct gsm_e1_subslot *dst_e1_ss = lookup_trau_mux_map(src_e1_ss);
+ struct subch_mux *mx;
+ struct upqueue_entry *ue;
+ int rc;
+
+ /* decode TRAU, change it to downlink, re-encode */
+ rc = decode_trau_frame(&tf, trau_bits);
+ if (rc)
+ 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;
+ if (memcmp(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_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;
+ trau_tx_to_mncc(ue->net, msg);
+
+ return 0;
+ }
+
+ mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts);
+ if (!mx)
+ return -EINVAL;
+
+ trau_frame_up2down(&tf);
+ 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,
+ TRAU_FRAME_BITS);
+}
+
+/* add receiver instance for lchan and callref */
+int trau_recv_lchan(struct gsm_lchan *lchan, u_int32_t callref)
+{
+ struct gsm_e1_subslot *src_ss;
+ struct upqueue_entry *ue;
+
+ ue = talloc(tall_upq_ctx, struct upqueue_entry);
+ if (!ue)
+ return -ENOMEM;
+
+ src_ss = &lchan->ts->e1_link;
+
+ DEBUGP(DCC, "Setting up TRAU receiver (e1=%u,ts=%u,ss=%u) "
+ "and (callref 0x%x)\n",
+ src_ss->e1_nr, src_ss->e1_ts, src_ss->e1_ts_ss,
+ callref);
+
+ /* make sure to get rid of any stale old mappings */
+ trau_mux_unmap(src_ss, callref);
+
+ memcpy(&ue->src, src_ss, sizeof(ue->src));
+ ue->net = lchan->ts->trx->bts->network;
+ ue->callref = callref;
+ llist_add(&ue->list, &ss_upqueue);
+
+ return 0;
+}
+
+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;
+
+ 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,
+ TRAU_FRAME_BITS);
+}