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osmo-bsc/src/libtrau/trau_mux.c

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/* 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 <openbsc/gsm_data.h>
#include <osmocom/abis/trau_frame.h>
#include <openbsc/trau_mux.h>
#include <osmocom/abis/subchan_demux.h>
#include <osmocom/abis/e1_input.h>
#include <openbsc/debug.h>
#include <osmocom/core/talloc.h>
#include <openbsc/trau_upqueue.h>
#include <osmocom/core/crcgen.h>
#include <openbsc/transaction.h>
/* this corresponds to the bit-lengths of the individual codec
* parameters as indicated in Table 1.1 of TS 06.10 */
static const uint8_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
};
/*
* EFR TRAU parity
*
* g(x) = x^3 + x^1 + 1
*/
static const struct osmo_crc8gen_code gsm0860_efr_crc3 = {
.bits = 3,
.poly = 0x3,
.init = 0x0,
.remainder = 0x7,
};
/* EFR parity bits */
static inline void efr_parity_bits_1(ubit_t *check_bits, const ubit_t *d_bits)
{
memcpy(check_bits + 0 , d_bits + 0, 22);
memcpy(check_bits + 22 , d_bits + 24, 3);
check_bits[25] = d_bits[28];
}
static inline void efr_parity_bits_2(ubit_t *check_bits, const ubit_t *d_bits)
{
memcpy(check_bits + 0 , d_bits + 42, 10);
memcpy(check_bits + 10 , d_bits + 90, 2);
}
static inline void efr_parity_bits_3(ubit_t *check_bits, const ubit_t *d_bits)
{
memcpy(check_bits + 0 , d_bits + 98, 5);
check_bits[5] = d_bits[104];
memcpy(check_bits + 6 , d_bits + 143, 2);
}
static inline void efr_parity_bits_4(ubit_t *check_bits, const ubit_t *d_bits)
{
memcpy(check_bits + 0 , d_bits + 151, 10);
memcpy(check_bits + 10 , d_bits + 199, 2);
}
static inline void efr_parity_bits_5(ubit_t *check_bits, const ubit_t *d_bits)
{
memcpy(check_bits + 0 , d_bits + 207, 5);
check_bits[5] = d_bits[213];
memcpy(check_bits + 6 , d_bits + 252, 2);
}
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;
uint32_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(DLMIB, 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, uint32_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 uint8_t c_bits_check_fr[] = { 0, 0, 0, 1, 0 };
static const uint8_t c_bits_check_efr[] = { 1, 1, 0, 1, 0 };
struct msgb *trau_decode_fr(uint32_t callref,
const struct decoded_trau_frame *tf)
{
struct msgb *msg;
struct gsm_data_frame *frame;
unsigned char *data;
int i, j, k, l, o;
msg = msgb_alloc(sizeof(struct gsm_data_frame) + 33,
"GSM-DATA");
if (!msg)
return NULL;
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)));
/* to avoid out-of-bounds access in gsm_fr_map[++l] */
if (i == 259)
break;
if (--k < 0) {
o += gsm_fr_map[l];
k = gsm_fr_map[++l]-1;
}
i++;
j++;
}
if (tf->c_bits[11]) /* BFI */
frame->msg_type = GSM_BAD_FRAME;
else
frame->msg_type = GSM_TCHF_FRAME;
frame->callref = callref;
msgb_put(msg, sizeof(struct gsm_data_frame) + 33);
return msg;
}
struct msgb *trau_decode_efr(uint32_t callref,
const struct decoded_trau_frame *tf)
{
struct msgb *msg;
struct gsm_data_frame *frame;
unsigned char *data;
int i, j, rc;
ubit_t check_bits[26];
msg = msgb_alloc(sizeof(struct gsm_data_frame) + 31,
"GSM-DATA");
if (!msg)
return NULL;
frame = (struct gsm_data_frame *)msg->data;
memset(frame, 0, sizeof(struct gsm_data_frame));
frame->msg_type = GSM_TCHF_FRAME_EFR;
frame->callref = callref;
msgb_put(msg, sizeof(struct gsm_data_frame) + 31);
if (tf->c_bits[11]) /* BFI */
goto bad_frame;
data = frame->data;
data[0] = 0xc << 4;
/* reassemble d-bits */
for (i = 1, j = 4; i < 39; i++, j++)
data[j/8] |= (tf->d_bits[i] << (7-(j%8)));
efr_parity_bits_1(check_bits, tf->d_bits);
rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 26,
tf->d_bits + 39);
if (rc)
goto bad_frame;
for (i = 42, j = 42; i < 95; i++, j++)
data[j/8] |= (tf->d_bits[i] << (7-(j%8)));
efr_parity_bits_2(check_bits, tf->d_bits);
rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 12,
tf->d_bits + 95);
if (rc)
goto bad_frame;
for (i = 98, j = 95; i < 148; i++, j++)
data[j/8] |= (tf->d_bits[i] << (7-(j%8)));
efr_parity_bits_3(check_bits, tf->d_bits);
rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 8,
tf->d_bits + 148);
if (rc)
goto bad_frame;
for (i = 151, j = 145; i < 204; i++, j++)
data[j/8] |= (tf->d_bits[i] << (7-(j%8)));
efr_parity_bits_4(check_bits, tf->d_bits);
rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 12,
tf->d_bits + 204);
if (rc)
goto bad_frame;
for (i = 207, j = 198; i < 257; i++, j++)
data[j/8] |= (tf->d_bits[i] << (7-(j%8)));
efr_parity_bits_5(check_bits, tf->d_bits);
rc = osmo_crc8gen_check_bits(&gsm0860_efr_crc3, check_bits, 8,
tf->d_bits + 257);
if (rc)
goto bad_frame;
return msg;
bad_frame:
frame->msg_type = GSM_BAD_FRAME;
return msg;
}
/* we get called by subchan_demux */
int trau_mux_input(struct gsm_e1_subslot *src_e1_ss,
const uint8_t *trau_bits, int num_bits)
{
struct decoded_trau_frame tf;
uint8_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 = NULL;
/* 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_fr, 5))
msg = trau_decode_fr(ue->callref, &tf);
else if (!memcmp(tf.c_bits, c_bits_check_efr, 5))
msg = trau_decode_efr(ue->callref, &tf);
else {
DEBUGPC(DLMUX, "illegal trau (C1-C5) %s\n",
osmo_hexdump(tf.c_bits, 5));
DEBUGPC(DLMUX, "test trau (C1-C5) %s\n",
osmo_hexdump(c_bits_check_efr, 5));
return -EINVAL;
}
if (!msg)
return -ENOMEM;
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);
}
/* callback when a TRAU frame was received */
int subch_cb(struct subch_demux *dmx, int ch, uint8_t *data, int len,
void *_priv)
{
struct e1inp_ts *e1i_ts = _priv;
struct gsm_e1_subslot src_ss;
src_ss.e1_nr = e1i_ts->line->num;
src_ss.e1_ts = e1i_ts->num;
src_ss.e1_ts_ss = ch;
return trau_mux_input(&src_ss, data, len);
}
/* add receiver instance for lchan and callref */
int trau_recv_lchan(struct gsm_lchan *lchan, uint32_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;
}
void trau_encode_fr(struct decoded_trau_frame *tf,
const unsigned char *data)
{
int i, j, k, l, o;
/* 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;
/* to avoid out-of-bounds access in gsm_fr_map[++l] */
if (i == 259)
break;
if (--k < 0) {
o += gsm_fr_map[l];
k = gsm_fr_map[++l]-1;
}
i++;
j++;
}
}
void trau_encode_efr(struct decoded_trau_frame *tf,
const unsigned char *data)
{
int i, j;
ubit_t check_bits[26];
/* set c-bits and t-bits */
tf->c_bits[0] = 1;
tf->c_bits[1] = 1;
tf->c_bits[2] = 0;
tf->c_bits[3] = 1;
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 */
tf->d_bits[0] = 1;
for (i = 1, j = 4; i < 39; i++, j++)
tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1;
efr_parity_bits_1(check_bits, tf->d_bits);
osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 26,
tf->d_bits + 39);
for (i = 42, j = 42; i < 95; i++, j++)
tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1;
efr_parity_bits_2(check_bits, tf->d_bits);
osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 12,
tf->d_bits + 95);
for (i = 98, j = 95; i < 148; i++, j++)
tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1;
efr_parity_bits_3(check_bits, tf->d_bits);
osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 8,
tf->d_bits + 148);
for (i = 151, j = 145; i < 204; i++, j++)
tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1;
efr_parity_bits_4(check_bits, tf->d_bits);
osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 12,
tf->d_bits + 204);
for (i = 207, j = 198; i < 257; i++, j++)
tf->d_bits[i] = (data[j/8] >> (7-(j%8))) & 1;
efr_parity_bits_5(check_bits, tf->d_bits);
osmo_crc8gen_set_bits(&gsm0860_efr_crc3, check_bits, 8,
tf->d_bits + 257);
}
int trau_send_frame(struct gsm_lchan *lchan, struct gsm_data_frame *frame)
{
uint8_t trau_bits_out[TRAU_FRAME_BITS];
struct gsm_e1_subslot *dst_e1_ss = &lchan->ts->e1_link;
struct subch_mux *mx;
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:
trau_encode_fr(&tf, frame->data);
break;
case GSM_TCHF_FRAME_EFR:
trau_encode_efr(&tf, frame->data);
break;
default:
DEBUGPC(DLMUX, "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);
}
/* switch trau muxer to new lchan */
int switch_trau_mux(struct gsm_lchan *old_lchan, struct gsm_lchan *new_lchan)
{
struct gsm_network *net = old_lchan->ts->trx->bts->network;
struct gsm_trans *trans;
/* look up transaction with TCH frame receive enabled */
llist_for_each_entry(trans, &net->trans_list, entry) {
if (trans->conn && trans->conn->lchan == old_lchan && trans->tch_recv) {
/* switch */
trau_recv_lchan(new_lchan, trans->callref);
}
}
return 0;
}
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