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/*
* (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
*
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <stdint.h>
#include <errno.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/gsm48.h>
#include <osmocom/gsm/rsl.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/protocol/gsm_04_14.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/bb/common/osmocom_data.h>
#include <osmocom/bb/common/logging.h>
#include <l1ctl_proto.h>
int gsm48_rr_tx_rr_status(struct osmocom_ms *ms, uint8_t cause);
int gsm48_send_rsl(struct osmocom_ms *ms, uint8_t msg_type,
struct msgb *msg, uint8_t link_id);
struct msgb *gsm48_l3_msgb_alloc(void);
#define loop_mode_name(mode) \
get_value_string(loop_mode_names, mode)
static const struct value_string loop_mode_names[] = {
{ L1CTL_TCH_LOOP_OPEN, "(OPEN)" },
{ L1CTL_TCH_LOOP_A, "A" },
{ L1CTL_TCH_LOOP_B, "B" },
{ L1CTL_TCH_LOOP_C, "C" },
{ L1CTL_TCH_LOOP_D, "D" },
{ L1CTL_TCH_LOOP_E, "E" },
{ L1CTL_TCH_LOOP_F, "F" },
{ L1CTL_TCH_LOOP_I, "I" },
{ 0, NULL }
};
static struct msgb *alloc_gsm414_msg(uint8_t msg_type)
{
struct gsm48_hdr *ngh;
struct msgb *nmsg;
nmsg = gsm48_l3_msgb_alloc();
if (nmsg == NULL)
return NULL;
ngh = (struct gsm48_hdr *) msgb_put(nmsg, sizeof(*ngh));
ngh->proto_discr = GSM48_PDISC_TEST;
ngh->msg_type = msg_type;
return nmsg;
}
static int handle_close_tch_loop(struct osmocom_ms *ms, const struct msgb *msg)
{
struct gsm48_rrlayer *rr = &ms->rrlayer;
const struct gsm48_hdr *gh = msgb_l3(msg);
unsigned int msg_len = msgb_l3len(msg);
struct msgb *nmsg;
/* Make sure that we have an active connection */
if (rr->state != GSM48_RR_ST_DEDICATED) {
LOGP(DMM, LOGL_NOTICE, "TCH loop requires an active connection\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
/* Make sure that the established channel is either TCH/F or TCH/H */
if ((rr->cd_now.chan_nr & 0xf8) != RSL_CHAN_Bm_ACCHs
&& (rr->cd_now.chan_nr & 0xf0) != RSL_CHAN_Lm_ACCHs) {
LOGP(DMM, LOGL_NOTICE, "TCH loop requires a TCH/F or TCH/H connection\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
/* Check if a loop is already closed */
if (rr->tch_loop_mode != L1CTL_TCH_LOOP_OPEN) {
LOGP(DMM, LOGL_NOTICE, "TCH loop has already been closed\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
if ((msg_len - sizeof(*gh)) < 1)
return -EINVAL;
/* Parse type of the TCH test loop, convert to L1CTL format */
uint8_t gsm414_loop_mode = (gh->data[0] >> 1) & 0x1f;
/* NOTE: some bits are not specified, so they can be 0 or 1 */
if (gsm414_loop_mode == GSM414_LOOP_A)
rr->tch_loop_mode = L1CTL_TCH_LOOP_A;
else if (gsm414_loop_mode == GSM414_LOOP_B)
rr->tch_loop_mode = L1CTL_TCH_LOOP_B;
else if ((gsm414_loop_mode & 0x1e) == GSM414_LOOP_C)
rr->tch_loop_mode = L1CTL_TCH_LOOP_C;
else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_D)
rr->tch_loop_mode = L1CTL_TCH_LOOP_D;
else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_E)
rr->tch_loop_mode = L1CTL_TCH_LOOP_E;
else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_F)
rr->tch_loop_mode = L1CTL_TCH_LOOP_F;
else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_I)
rr->tch_loop_mode = L1CTL_TCH_LOOP_I;
else {
LOGP(DMM, LOGL_NOTICE, "Unhandled 3GPP TS 44.014 TCH loop "
"mode=0x%02x => rejecting\n", gsm414_loop_mode);
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N);
return -ENOTSUP;
}
LOGP(DMM, LOGL_NOTICE, "(%s) Closing 3GPP TS 44.014 TCH loop mode '%s'\n",
rsl_chan_nr_str(rr->cd_now.chan_nr), loop_mode_name(rr->tch_loop_mode));
/* Instruct the L1 to enable received TCH loopback mode
* FIXME: delay applying this mode, so we can send the ACK first */
l1ctl_tx_tch_mode_req(ms, rr->cd_now.mode, rr->audio_mode, rr->tch_loop_mode);
/* Craft and send the ACKnowledgement */
nmsg = alloc_gsm414_msg(GSM414_MT_CLOSE_TCH_LOOP_ACK);
if (nmsg == NULL)
return -ENOMEM;
return gsm48_send_rsl(ms, RSL_MT_DATA_REQ, nmsg, 0);
}
static int handle_open_tch_loop(struct osmocom_ms *ms, const struct msgb *msg)
{
struct gsm48_rrlayer *rr = &ms->rrlayer;
struct msgb *nmsg;
/* Make sure that we have an active connection */
if (rr->state != GSM48_RR_ST_DEDICATED) {
LOGP(DMM, LOGL_NOTICE, "TCH loop requires an active connection\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
/* Make sure that the established channel is either TCH/F or TCH/H */
if ((rr->cd_now.chan_nr & 0xf8) != RSL_CHAN_Bm_ACCHs
&& (rr->cd_now.chan_nr & 0xf0) != RSL_CHAN_Lm_ACCHs) {
LOGP(DMM, LOGL_NOTICE, "TCH loop requires a TCH/F or TCH/H connection\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
/* Check if a loop actually needs to be closed */
if (rr->tch_loop_mode == L1CTL_TCH_LOOP_OPEN) {
LOGP(DMM, LOGL_NOTICE, "TCH loop has not been closed (already open)\n");
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
return -EINVAL;
}
LOGP(DMM, LOGL_NOTICE, "(%s) Opening 3GPP TS 44.014 TCH loop mode '%s'\n",
rsl_chan_nr_str(rr->cd_now.chan_nr), loop_mode_name(rr->tch_loop_mode));
/* Instruct the L1 to disable the TCH loopback mode */
l1ctl_tx_tch_mode_req(ms, rr->cd_now.mode, rr->audio_mode, L1CTL_TCH_LOOP_OPEN);
/* Only the loop mode C needs to be ACKnowledged */
bool needs_ack = rr->tch_loop_mode == L1CTL_TCH_LOOP_C;
rr->tch_loop_mode = L1CTL_TCH_LOOP_OPEN;
if (!needs_ack)
return 0;
/* Craft and send the ACKnowledgement */
nmsg = alloc_gsm414_msg(GSM414_MT_OPEN_LOOP_CMD);
if (nmsg == NULL)
return -ENOMEM;
msgb_put_u8(nmsg, GSM414_OPEN_LOOP_ACK_IE);
return gsm48_send_rsl(ms, RSL_MT_DATA_REQ, nmsg, 0);
}
int gsm414_rcv_test(struct osmocom_ms *ms, const struct msgb *msg)
{
const struct gsm48_hdr *gh = msgb_l3(msg);
LOGP(DMM, LOGL_INFO, "Received 3GPP TS 44.014 message '%s' (0x%02x)\n",
get_value_string(gsm414_msgt_names, gh->msg_type), gh->msg_type);
/* TODO: check if the test SIM (special EF.ADM) is inserted */
switch (gh->msg_type) {
case GSM414_MT_CLOSE_TCH_LOOP_CMD:
return handle_close_tch_loop(ms, msg);
case GSM414_MT_OPEN_LOOP_CMD:
return handle_open_tch_loop(ms, msg);
default:
LOGP(DMM, LOGL_NOTICE, "Unhandled 3GPP TS 44.014 message '%s' (0x%02x)\n",
get_value_string(gsm414_msgt_names, gh->msg_type), gh->msg_type);
gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N);
return -ENOTSUP;
}
}
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