314 lines
7.7 KiB
C
314 lines
7.7 KiB
C
/* Simple TRAU frame reflector to route voice calls */
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/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <openbsc/gsm_data.h>
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#include <openbsc/trau_frame.h>
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#include <openbsc/trau_mux.h>
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#include <openbsc/subchan_demux.h>
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#include <openbsc/e1_input.h>
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#include <openbsc/debug.h>
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#include <osmocore/talloc.h>
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u_int8_t gsm_fr_map[] = {
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6, 6, 5, 5, 4, 4, 3, 3,
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7, 2, 2, 6, 3, 3, 3, 3,
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3, 3, 3, 3, 3, 3, 3, 3,
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3, 7, 2, 2, 6, 3, 3, 3,
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3, 3, 3, 3, 3, 3, 3, 3,
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3, 3, 7, 2, 2, 6, 3, 3,
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3, 3, 3, 3, 3, 3, 3, 3,
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3, 3, 3, 7, 2, 2, 6, 3,
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3, 3, 3, 3, 3, 3, 3, 3,
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3, 3, 3, 3
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};
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struct map_entry {
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struct llist_head list;
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struct gsm_e1_subslot src, dst;
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};
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struct upqueue_entry {
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struct llist_head list;
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struct gsm_network *net;
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struct gsm_e1_subslot src;
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u_int32_t callref;
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};
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static LLIST_HEAD(ss_map);
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static LLIST_HEAD(ss_upqueue);
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void *tall_map_ctx, *tall_upq_ctx;
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/* map one particular subslot to another subslot */
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int trau_mux_map(const struct gsm_e1_subslot *src,
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const struct gsm_e1_subslot *dst)
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{
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struct map_entry *me;
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me = talloc(tall_map_ctx, struct map_entry);
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if (!me) {
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LOGP(DMIB, LOGL_FATAL, "Out of memory\n");
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return -ENOMEM;
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}
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DEBUGP(DCC, "Setting up TRAU mux map between (e1=%u,ts=%u,ss=%u) "
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"and (e1=%u,ts=%u,ss=%u)\n",
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src->e1_nr, src->e1_ts, src->e1_ts_ss,
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dst->e1_nr, dst->e1_ts, dst->e1_ts_ss);
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/* make sure to get rid of any stale old mappings */
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trau_mux_unmap(src, 0);
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trau_mux_unmap(dst, 0);
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memcpy(&me->src, src, sizeof(me->src));
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memcpy(&me->dst, dst, sizeof(me->dst));
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llist_add(&me->list, &ss_map);
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return 0;
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}
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int trau_mux_map_lchan(const struct gsm_lchan *src,
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const struct gsm_lchan *dst)
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{
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struct gsm_e1_subslot *src_ss, *dst_ss;
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src_ss = &src->ts->e1_link;
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dst_ss = &dst->ts->e1_link;
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return trau_mux_map(src_ss, dst_ss);
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}
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/* unmap one particular subslot from another subslot */
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int trau_mux_unmap(const struct gsm_e1_subslot *ss, u_int32_t callref)
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{
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struct map_entry *me, *me2;
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struct upqueue_entry *ue, *ue2;
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if (ss)
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llist_for_each_entry_safe(me, me2, &ss_map, list) {
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if (!memcmp(&me->src, ss, sizeof(*ss)) ||
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!memcmp(&me->dst, ss, sizeof(*ss))) {
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llist_del(&me->list);
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return 0;
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}
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}
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llist_for_each_entry_safe(ue, ue2, &ss_upqueue, list) {
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if (ue->callref == callref) {
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llist_del(&ue->list);
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return 0;
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}
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if (ss && !memcmp(&ue->src, ss, sizeof(*ss))) {
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llist_del(&ue->list);
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return 0;
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}
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}
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return -ENOENT;
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}
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/* look-up an enty in the TRAU mux map */
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static struct gsm_e1_subslot *
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lookup_trau_mux_map(const struct gsm_e1_subslot *src)
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{
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struct map_entry *me;
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llist_for_each_entry(me, &ss_map, list) {
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if (!memcmp(&me->src, src, sizeof(*src)))
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return &me->dst;
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if (!memcmp(&me->dst, src, sizeof(*src)))
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return &me->src;
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}
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return NULL;
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}
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/* look-up an enty in the TRAU upqueue */
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struct upqueue_entry *
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lookup_trau_upqueue(const struct gsm_e1_subslot *src)
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{
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struct upqueue_entry *ue;
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llist_for_each_entry(ue, &ss_upqueue, list) {
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if (!memcmp(&ue->src, src, sizeof(*src)))
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return ue;
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}
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return NULL;
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}
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static const u_int8_t c_bits_check[] = { 0, 0, 0, 1, 0 };
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/* we get called by subchan_demux */
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int trau_mux_input(struct gsm_e1_subslot *src_e1_ss,
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const u_int8_t *trau_bits, int num_bits)
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{
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struct decoded_trau_frame tf;
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u_int8_t trau_bits_out[TRAU_FRAME_BITS];
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struct gsm_e1_subslot *dst_e1_ss = lookup_trau_mux_map(src_e1_ss);
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struct subch_mux *mx;
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struct upqueue_entry *ue;
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int rc;
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/* decode TRAU, change it to downlink, re-encode */
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rc = decode_trau_frame(&tf, trau_bits);
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if (rc)
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return rc;
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if (!dst_e1_ss) {
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struct msgb *msg;
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struct gsm_data_frame *frame;
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unsigned char *data;
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int i, j, k, l, o;
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/* frame shall be sent to upqueue */
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if (!(ue = lookup_trau_upqueue(src_e1_ss)))
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return -EINVAL;
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if (!ue->callref)
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return -EINVAL;
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if (memcmp(tf.c_bits, c_bits_check, sizeof(c_bits_check)))
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DEBUGPC(DMUX, "illegal trau (C1-C5) %s\n",
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hexdump(tf.c_bits, sizeof(c_bits_check)));
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msg = msgb_alloc(sizeof(struct gsm_data_frame) + 33,
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"GSM-DATA");
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if (!msg)
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return -ENOMEM;
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frame = (struct gsm_data_frame *)msg->data;
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memset(frame, 0, sizeof(struct gsm_data_frame));
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data = frame->data;
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data[0] = 0xd << 4;
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/* reassemble d-bits */
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i = 0; /* counts bits */
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j = 4; /* counts output bits */
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k = gsm_fr_map[0]-1; /* current number bit in element */
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l = 0; /* counts element bits */
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o = 0; /* offset input bits */
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while (i < 260) {
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data[j/8] |= (tf.d_bits[k+o] << (7-(j%8)));
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if (--k < 0) {
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o += gsm_fr_map[l];
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k = gsm_fr_map[++l]-1;
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}
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i++;
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j++;
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}
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frame->msg_type = GSM_TCHF_FRAME;
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frame->callref = ue->callref;
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msgb_enqueue(&ue->net->upqueue, msg);
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return 0;
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}
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mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts);
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if (!mx)
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return -EINVAL;
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trau_frame_up2down(&tf);
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encode_trau_frame(trau_bits_out, &tf);
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/* and send it to the muxer */
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return subchan_mux_enqueue(mx, dst_e1_ss->e1_ts_ss, trau_bits_out,
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TRAU_FRAME_BITS);
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}
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/* add receiver instance for lchan and callref */
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int trau_recv_lchan(struct gsm_lchan *lchan, u_int32_t callref)
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{
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struct gsm_e1_subslot *src_ss;
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struct upqueue_entry *ue;
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ue = talloc(tall_upq_ctx, struct upqueue_entry);
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if (!ue)
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return -ENOMEM;
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src_ss = &lchan->ts->e1_link;
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DEBUGP(DCC, "Setting up TRAU receiver (e1=%u,ts=%u,ss=%u) "
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"and (callref 0x%x)\n",
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src_ss->e1_nr, src_ss->e1_ts, src_ss->e1_ts_ss,
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callref);
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/* make sure to get rid of any stale old mappings */
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trau_mux_unmap(src_ss, callref);
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memcpy(&ue->src, src_ss, sizeof(ue->src));
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ue->net = lchan->ts->trx->bts->network;
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ue->callref = callref;
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llist_add(&ue->list, &ss_upqueue);
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return 0;
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}
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int trau_send_frame(struct gsm_lchan *lchan, struct gsm_data_frame *frame)
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{
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u_int8_t trau_bits_out[TRAU_FRAME_BITS];
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struct gsm_e1_subslot *dst_e1_ss = &lchan->ts->e1_link;
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struct subch_mux *mx;
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int i, j, k, l, o;
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unsigned char *data = frame->data;
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struct decoded_trau_frame tf;
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mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts);
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if (!mx)
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return -EINVAL;
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switch (frame->msg_type) {
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case GSM_TCHF_FRAME:
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/* set c-bits and t-bits */
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tf.c_bits[0] = 1;
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tf.c_bits[1] = 1;
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tf.c_bits[2] = 1;
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tf.c_bits[3] = 0;
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tf.c_bits[4] = 0;
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memset(&tf.c_bits[5], 0, 6);
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memset(&tf.c_bits[11], 1, 10);
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memset(&tf.t_bits[0], 1, 4);
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/* reassemble d-bits */
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i = 0; /* counts bits */
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j = 4; /* counts input bits */
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k = gsm_fr_map[0]-1; /* current number bit in element */
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l = 0; /* counts element bits */
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o = 0; /* offset output bits */
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while (i < 260) {
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tf.d_bits[k+o] = (data[j/8] >> (7-(j%8))) & 1;
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if (--k < 0) {
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o += gsm_fr_map[l];
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k = gsm_fr_map[++l]-1;
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}
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i++;
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j++;
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}
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break;
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default:
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DEBUGPC(DMUX, "unsupported message type %d\n",
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frame->msg_type);
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return -EINVAL;
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}
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encode_trau_frame(trau_bits_out, &tf);
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/* and send it to the muxer */
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return subchan_mux_enqueue(mx, dst_e1_ss->e1_ts_ss, trau_bits_out,
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TRAU_FRAME_BITS);
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}
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