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/*
* (C) 2010 by Andreas Eversberg <jolly@eversberg.eu>
* (C) 2017-2018 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2022-2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
*/
#include <string.h>
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/signal.h>
#include <osmocom/codec/codec.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/bb/common/logging.h>
#include <osmocom/bb/common/osmocom_data.h>
#include <osmocom/bb/common/ms.h>
#include <osmocom/bb/mobile/mncc.h>
#include <osmocom/bb/mobile/mncc_sock.h>
#include <osmocom/bb/mobile/transaction.h>
#include <osmocom/bb/mobile/tch.h>
int tch_voice_state_init(struct gsm_trans *trans,
struct tch_voice_state *state);
int tch_data_state_init(struct gsm_trans *trans,
struct tch_data_state *state);
void tch_voice_state_free(struct tch_voice_state *state);
void tch_data_state_free(struct tch_data_state *state);
int tch_voice_recv(struct osmocom_ms *ms, struct msgb *msg);
int tch_data_recv(struct osmocom_ms *ms, struct msgb *msg);
int tch_voice_serve_ms(struct osmocom_ms *ms);
/* Receive a Downlink traffic (voice/data) frame from the lower layers */
static int tch_recv_cb(struct osmocom_ms *ms, struct msgb *msg)
{
struct tch_state *state = ms->tch_state;
if (state == NULL) {
msgb_free(msg);
return 0;
}
if (state->is_voice) {
return tch_voice_recv(ms, msg);
} else {
/* Rx only mode makes no sense for data calls, so we discard
* received DL frames and thus do not trigger sending UL frames. */
if (!state->rx_only)
return tch_data_recv(ms, msg);
msgb_free(msg);
return 0;
}
}
/* Send an Uplink voice frame to the lower layers */
int tch_send_msg(struct osmocom_ms *ms, struct msgb *msg)
{
struct tch_state *state = ms->tch_state;
if (state == NULL || state->rx_only) {
/* TODO: fix callers and print a warning here */
msgb_free(msg);
return -EIO;
}
return gsm48_rr_tx_traffic(ms, msg);
}
/* tch_send_msg() wrapper accepting an MNCC structure */
int tch_send_mncc_frame(struct osmocom_ms *ms, const struct gsm_data_frame *frame)
{
struct msgb *nmsg;
int len;
switch (frame->msg_type) {
case GSM_TCHF_FRAME:
len = GSM_FR_BYTES;
break;
case GSM_TCHF_FRAME_EFR:
len = GSM_EFR_BYTES;
break;
case GSM_TCHH_FRAME:
len = GSM_HR_BYTES;
break;
/* TODO: case GSM_TCH_FRAME_AMR (variable length) */
/* TODO: case GSM_BAD_FRAME (empty?) */
default:
LOGP(DL1C, LOGL_ERROR, "%s(): msg_type=0x%02x: not implemented\n",
__func__, frame->msg_type);
return -EINVAL;
}
nmsg = msgb_alloc_headroom(len + 64, 64, "TCH/F");
if (!nmsg)
return -ENOMEM;
nmsg->l2h = msgb_put(nmsg, len);
memcpy(nmsg->l2h, frame->data, len);
return tch_send_msg(ms, nmsg);
}
int tch_serve_ms(struct osmocom_ms *ms)
{
struct tch_state *state = ms->tch_state;
int rc = 0;
if (state == NULL)
return 0;
if (state->is_voice)
rc = tch_voice_serve_ms(ms);
/* TODO: else tch_data_serve_ms() */
return rc;
}
static void tch_trans_cstate_active_cb(struct gsm_trans *trans, bool rx_only)
{
struct osmocom_ms *ms = trans->ms;
struct tch_state *state;
enum gsm48_chan_mode ch_mode;
if (ms->tch_state != NULL) {
ms->tch_state->rx_only = rx_only;
return; /* TODO: handle modify? */
}
state = talloc_zero(ms, struct tch_state);
OSMO_ASSERT(state != NULL);
ms->tch_state = state;
ms->tch_state->rx_only = rx_only;
ch_mode = ms->rrlayer.cd_now.mode;
switch (ch_mode) {
case GSM48_CMODE_SPEECH_V1:
case GSM48_CMODE_SPEECH_EFR:
case GSM48_CMODE_SPEECH_AMR:
state->is_voice = true;
state->voice.handler = ms->settings.tch_voice.io_handler;
if (tch_voice_state_init(trans, &state->voice) != 0)
goto exit_free;
break;
case GSM48_CMODE_DATA_14k5:
case GSM48_CMODE_DATA_12k0:
case GSM48_CMODE_DATA_6k0:
case GSM48_CMODE_DATA_3k6:
state->is_voice = false;
state->data.handler = ms->settings.tch_data.io_handler;
if (tch_data_state_init(trans, &state->data) != 0)
goto exit_free;
break;
case GSM48_CMODE_SIGN:
default:
LOGP(DL1C, LOGL_ERROR, "Unhandled channel mode %s\n",
get_value_string(gsm48_chan_mode_names, ch_mode));
exit_free:
talloc_free(state);
ms->tch_state = NULL;
return;
}
}
static void tch_trans_free_cb(struct gsm_trans *trans)
{
struct osmocom_ms *ms = trans->ms;
struct tch_state *state = ms->tch_state;
if (state == NULL)
return;
if (state->is_voice)
tch_voice_state_free(&state->voice);
else
tch_data_state_free(&state->data);
talloc_free(state);
ms->tch_state = NULL;
}
static void tch_trans_state_chg_cb(struct gsm_trans *trans)
{
switch (trans->cc.state) {
case GSM_CSTATE_CALL_DELIVERED: /* MO call: Rx CC ALERTING */
tch_trans_cstate_active_cb(trans, true);
break;
case GSM_CSTATE_ACTIVE: /* MO/MT call: Rx CC CONNECT */
tch_trans_cstate_active_cb(trans, false);
break;
case GSM_CSTATE_NULL:
tch_trans_free_cb(trans);
break;
}
}
/* a call-back for CC (Call Control) transaction related events */
static int tch_trans_signal_cb(unsigned int subsys, unsigned int signal,
void *handler_data, void *signal_data)
{
struct gsm_trans *trans = signal_data;
OSMO_ASSERT(subsys == SS_L23_TRANS);
OSMO_ASSERT(trans != NULL);
/* we only care about CC transactions here */
if (trans->protocol != GSM48_PDISC_CC)
return 0;
switch ((enum osmobb_l23_trans_sig)signal) {
case S_L23_CC_TRANS_ALLOC:
break;
case S_L23_CC_TRANS_FREE:
tch_trans_free_cb(trans);
break;
case S_L23_CC_TRANS_STATE_CHG:
tch_trans_state_chg_cb(trans);
break;
}
return 0;
}
/* Initialize the TCH router */
int tch_init(struct osmocom_ms *ms)
{
ms->l1_entity.l1_traffic_ind = &tch_recv_cb;
osmo_signal_register_handler(SS_L23_TRANS, &tch_trans_signal_cb, ms);
return 0;
}
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