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/* Maintain and generate ASCI notifications */
/*
* (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* SPDX-License-Identifier: AGPL-3.0+
*
* Author: Harald Welte
*
* 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 <osmocom/core/bitvec.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/notification.h>
static struct asci_notification *bts_asci_notification_find(struct gsm_bts *bts, const uint8_t *group_call_ref)
{
struct asci_notification *n;
llist_for_each_entry(n, &bts->asci.notifications, list) {
if (!memcmp(n->group_call_ref, group_call_ref, sizeof(n->group_call_ref)))
return n;
}
return NULL;
}
int bts_asci_notification_add(struct gsm_bts *bts, const uint8_t *group_call_ref, const uint8_t *chan_desc,
uint8_t chan_desc_len, const struct rsl_ie_nch_drx_info *nch_drx_info)
{
struct asci_notification *n;
if (bts_asci_notification_find(bts, group_call_ref))
return -EEXIST;
n = talloc_zero(bts, struct asci_notification);
if (!n)
return -ENOMEM;
memcpy(n->group_call_ref, group_call_ref, sizeof(n->group_call_ref));
if (chan_desc && chan_desc_len) {
n->chan_desc.present = true;
n->chan_desc.len = chan_desc_len;
memcpy(&n->chan_desc.value, chan_desc, chan_desc_len);
}
if (nch_drx_info) {
n->nch_drx_info.present = true;
n->nch_drx_info.value = *nch_drx_info;
}
LOGP(DASCI, LOGL_INFO, "Added ASCI Notification for group call reference %s\n",
osmo_hexdump_nospc(n->group_call_ref, ARRAY_SIZE(n->group_call_ref)));
/* add at beginning of "queue" to make sure a new call is notified first */
llist_add(&n->list, &bts->asci.notifications);
bts->asci.notification_entries++;
bts->asci.notification_count = 0;
bts->asci.nln = (bts->asci.nln + 1) % 4;
return 0;
}
int bts_asci_notification_del(struct gsm_bts *bts, const uint8_t *group_call_ref)
{
struct asci_notification *n = bts_asci_notification_find(bts, group_call_ref);
if (!n)
return -ENODEV;
LOGP(DASCI, LOGL_INFO, "Deleting ASCI Notification for group call reference %s\n",
osmo_hexdump_nospc(n->group_call_ref, ARRAY_SIZE(n->group_call_ref)));
llist_del(&n->list);
talloc_free(n);
bts->asci.notification_entries--;
bts->asci.notification_count = 0;
bts->asci.nln_status = (bts->asci.nln_status + 1) % 2;
return 0;
}
int bts_asci_notification_reset(struct gsm_bts *bts)
{
struct asci_notification *n, *n2;
LOGP(DASCI, LOGL_INFO, "Deleting all %u ASCI Notifications of BTS\n",
llist_count(&bts->asci.notifications));
llist_for_each_entry_safe(n, n2, &bts->asci.notifications, list) {
llist_del(&n->list);
talloc_free(n);
}
bts->asci.notification_entries = 0;
bts->asci.notification_count = 0;
bts->asci.nln_status = (bts->asci.nln_status + 1) % 2;
return 0;
}
const struct asci_notification *bts_asci_notification_get_next(struct gsm_bts *bts)
{
struct asci_notification *n;
n = llist_first_entry_or_null(&bts->asci.notifications, struct asci_notification, list);
if (!n)
return NULL;
/* move to end of list to iterate over them */
llist_del(&n->list);
llist_add_tail(&n->list, &bts->asci.notifications);
return n;
}
/*! append a "Group Call Information" CSN.1 structure to the caller-provided bit-vector.
* \param[out] bv caller-provided output bit-vector
* \param[in] gcr 5-byte group call reference
* \param[in] ch_desc optional group channel description (may be NULL)
* \param[in] ch_desc_len length of group channel description (in bytes) */
void append_group_call_information(struct bitvec *bv, const uint8_t *gcr, const uint8_t *ch_desc, uint8_t ch_desc_len)
{
/* spec reference: TS 44.018 Section 9.1.21a */
/* <Group Call Reference : bit(36)> */
struct bitvec *gcr_bv = bitvec_alloc(5*8, NULL);
OSMO_ASSERT(gcr_bv);
bitvec_unpack(gcr_bv, gcr);
for (unsigned int i = 0; i < 36; i++)
bitvec_set_bit(bv, bitvec_get_bit_pos(gcr_bv, i));
/* Group Channel Description */
if (ch_desc && ch_desc_len) {
struct bitvec *chd_bv = bitvec_alloc(ch_desc_len*8, NULL);
OSMO_ASSERT(chd_bv);
bitvec_unpack(chd_bv, ch_desc);
bitvec_set_bit(bv, 1);
/* <Channel Description : bit(24)> */
for (unsigned int i = 0; i < ch_desc_len * 8; i++)
bitvec_set_bit(bv, bitvec_get_bit_pos(chd_bv, i));
bitvec_free(chd_bv);
/* FIXME: hopping */
bitvec_set_bit(bv, 0);
} else {
bitvec_set_bit(bv, 0);
}
bitvec_free(gcr_bv);
}
#define L2_PLEN(len) (((len - 1) << 2) | 0x01)
int bts_asci_notify_nch_gen_msg(struct gsm_bts *bts, uint8_t *out_buf)
{
struct gsm48_notification_nch *nn = (struct gsm48_notification_nch *) out_buf;
const struct asci_notification *notif;
unsigned int ro_len;
notif = bts_asci_notification_get_next(bts);
*nn = (struct gsm48_notification_nch) {
.proto_discr = GSM48_PDISC_RR,
.msg_type = GSM48_MT_RR_NOTIF_NCH,
};
nn->l2_plen = L2_PLEN(nn->data - out_buf);
/* Pad remaining octets with constant '2B'O */
ro_len = GSM_MACBLOCK_LEN - (nn->data - out_buf);
memset(nn->data, GSM_MACBLOCK_PADDING, ro_len);
struct bitvec bv = {
.data_len = ro_len,
.data = nn->data,
};
/* {0 | 1 < NLN(NCH) : bit (2) >}
* Only send NLN, at the last notifications.
* When the phone receives two NLN with the same value, it knows that all notifications has been received.
* Also send NLN if no notification is available. */
if (bts->asci.notification_count >= bts->asci.notification_entries - 1) {
bitvec_set_bit(&bv, 1);
bitvec_set_uint(&bv, bts->asci.nln, 2);
} else {
bitvec_set_bit(&bv, 0);
}
/* Count NLN. */
if (++bts->asci.notification_count >= bts->asci.notification_entries)
bts->asci.notification_count = 0;
/* < List of Group Call NCH information > ::=
* { 0 | 1 < Group Call information > < List of Group Call NCH information > } ; */
if (notif) {
bitvec_set_bit(&bv, 1);
append_group_call_information(&bv, notif->group_call_ref,
notif->chan_desc.present ? notif->chan_desc.value : NULL,
notif->chan_desc.len);
}
bitvec_set_bit(&bv, 0); /* End of list */
/* TODO: Additions in Release 6 */
/* TODO: Additions in Release 7 */
return GSM_MACBLOCK_LEN;
}
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