/* A hackish minimal BSC (+MSC +HLR) implementation */

/* (C) 2008-2018 by Harald Welte <laforge@gnumonks.org>
 * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.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 <osmocom/bsc/gsm_data.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/bsc/abis_rsl.h>
#include <osmocom/bsc/debug.h>
#include <osmocom/bsc/misdn.h>
#include <osmocom/bsc/system_information.h>
#include <osmocom/bsc/paging.h>
#include <osmocom/bsc/signal.h>
#include <osmocom/bsc/chan_alloc.h>
#include <osmocom/core/talloc.h>
#include <osmocom/bsc/ipaccess.h>
#include <osmocom/gsm/sysinfo.h>
#include <osmocom/bsc/pcu_if.h>
#include <osmocom/bsc/bsc_msc_data.h>
#include <osmocom/bsc/handover_cfg.h>
#include <osmocom/bsc/gsm_04_08_rr.h>
#include <osmocom/bsc/neighbor_ident.h>
#include <osmocom/bsc/bts.h>
#include <osmocom/bsc/lb.h>
#include <osmocom/bsc/bsc_stats.h>

#include <osmocom/bsc/smscb.h>
#include <osmocom/gsm/protocol/gsm_48_049.h>

#include <time.h>
#include <limits.h>
#include <stdbool.h>

struct gsm_network *bsc_gsmnet;

int bsc_shutdown_net(struct gsm_network *net)
{
	struct gsm_bts *bts;

	llist_for_each_entry(bts, &net->bts_list, list) {
		LOGP(DNM, LOGL_NOTICE, "shutting down OML for BTS %u\n", bts->nr);
		osmo_signal_dispatch(SS_L_GLOBAL, S_GLOBAL_BTS_CLOSE_OM, bts);
	}

	return 0;
}

/* XXX hard-coded for now */
#define T3122_CHAN_LOAD_SAMPLE_INTERVAL 1 /* in seconds */

static void update_t3122_chan_load_timer(void *data)
{
	struct gsm_network *net = data;
	struct gsm_bts *bts;

	llist_for_each_entry(bts, &net->bts_list, list)
		bts_update_t3122_chan_load(bts);

	/* Keep this timer ticking. */
	osmo_timer_schedule(&net->t3122_chan_load_timer, T3122_CHAN_LOAD_SAMPLE_INTERVAL, 0);
}

static void bsc_store_bts_uptime(void *data)
{
	struct gsm_network *net = data;
	struct gsm_bts *bts;

	llist_for_each_entry(bts, &net->bts_list, list)
		bts_store_uptime(bts);

	/* Keep this timer ticking. */
	osmo_timer_schedule(&net->bts_store_uptime_timer, BTS_STORE_UPTIME_INTERVAL, 0);
}

static void bsc_store_bts_lchan_durations(void *data)
{
	struct gsm_network *net = data;
	struct gsm_bts *bts;

	llist_for_each_entry(bts, &net->bts_list, list)
		bts_store_lchan_durations(bts);

	/* Keep this timer ticking. */
	osmo_timer_schedule(&net->bts_store_lchan_durations_timer, BTS_STORE_LCHAN_DURATIONS_INTERVAL, 0);
}

static struct gsm_network *bsc_network_init(void *ctx)
{
	struct gsm_network *net = gsm_network_init(ctx);

	net->cbc = talloc_zero(net, struct bsc_cbc_link);
	if (!net->cbc) {
		goto err_out;
	}

	/* Init back pointer */
	net->auto_off_timeout = -1;
	INIT_LLIST_HEAD(&net->mscs);

	net->ho = ho_cfg_init(net, NULL);
	net->hodec2.congestion_check_interval_s = HO_CFG_CONGESTION_CHECK_DEFAULT;

	/* init statistics */
	net->bsc_ctrs = rate_ctr_group_alloc(net, &bsc_ctrg_desc, 0);
	if (!net->bsc_ctrs)
		goto err_out;
	net->bsc_statg = osmo_stat_item_group_alloc(net, &bsc_statg_desc, 0);
	if (!net->bsc_statg)
		goto err_free_bsc_ctr;

	/* init statistics */
	net->bts_unknown_ctrs = rate_ctr_group_alloc(net, &bts_ctrg_desc, BTS_STAT_IDX_UNKNOWN);
	if (!net->bts_unknown_ctrs)
		goto err_free_bsc_ctr_stat;
	net->bts_unknown_statg = osmo_stat_item_group_alloc(net, &bts_statg_desc, BTS_STAT_IDX_UNKNOWN);
	if (!net->bts_unknown_statg)
		goto err_free_all;

	net->all_allocated.sdcch = (struct osmo_time_cc){
		.cfg = {
			.gran_usec = 1*1000000,
			.forget_sum_usec = 60*1000000,
			.rate_ctr = rate_ctr_group_get_ctr(net->bsc_ctrs, BSC_CTR_ALL_ALLOCATED_SDCCH),
			.T_gran = -16,
			.T_round_threshold = -17,
			.T_forget_sum = -18,
			.T_defs = net->T_defs,
		},
	};
	net->all_allocated.static_sdcch = (struct osmo_time_cc){
		.cfg = {
			.gran_usec = 1*1000000,
			.forget_sum_usec = 60*1000000,
			.rate_ctr = rate_ctr_group_get_ctr(net->bsc_ctrs, BSC_CTR_ALL_ALLOCATED_STATIC_SDCCH),
			.T_gran = -16,
			.T_round_threshold = -17,
			.T_forget_sum = -18,
			.T_defs = net->T_defs,
		},
	};
	net->all_allocated.tch = (struct osmo_time_cc){
		.cfg = {
			.gran_usec = 1*1000000,
			.forget_sum_usec = 60*1000000,
			.rate_ctr = rate_ctr_group_get_ctr(net->bsc_ctrs, BSC_CTR_ALL_ALLOCATED_TCH),
			.T_gran = -16,
			.T_round_threshold = -17,
			.T_forget_sum = -18,
			.T_defs = net->T_defs,
		},
	};
	net->all_allocated.static_tch = (struct osmo_time_cc){
		.cfg = {
			.gran_usec = 1*1000000,
			.forget_sum_usec = 60*1000000,
			.rate_ctr = rate_ctr_group_get_ctr(net->bsc_ctrs, BSC_CTR_ALL_ALLOCATED_STATIC_TCH),
			.T_gran = -16,
			.T_round_threshold = -17,
			.T_forget_sum = -18,
			.T_defs = net->T_defs,
		},
	};

	INIT_LLIST_HEAD(&net->bts_rejected);
	gsm_net_update_ctype(net);

	/*
	 * At present all BTS in the network share one channel load timeout.
	 * If this becomes a problem for networks with a lot of BTS, this
	 * code could be refactored to run the timeout individually per BTS.
	 */
	osmo_timer_setup(&net->t3122_chan_load_timer, update_t3122_chan_load_timer, net);
	osmo_timer_schedule(&net->t3122_chan_load_timer, T3122_CHAN_LOAD_SAMPLE_INTERVAL, 0);

	/* Init uptime tracking timer. */
	osmo_timer_setup(&net->bts_store_uptime_timer, bsc_store_bts_uptime, net);
	osmo_timer_schedule(&net->bts_store_uptime_timer, BTS_STORE_UPTIME_INTERVAL, 0);

	/* Init lchan duration tracking timer. */
	osmo_timer_setup(&net->bts_store_lchan_durations_timer, bsc_store_bts_lchan_durations, net);
	osmo_timer_schedule(&net->bts_store_lchan_durations_timer, BTS_STORE_LCHAN_DURATIONS_INTERVAL, 0);

	net->cbc->net = net;
	net->cbc->mode = BSC_CBC_LINK_MODE_DISABLED;
	net->cbc->server.local_addr = bsc_cbc_default_server_local_addr;
	/* For CBSP client mode: default remote CBSP server port is CBSP_TCP_PORT == 48049. Leave the IP address unset.
	 * Also leave the local bind for the CBSP client disabled (unconfigured). */
	net->cbc->client.remote_addr = (struct osmo_sockaddr_str){ .port = CBSP_TCP_PORT, };
	net->cbc->client.local_addr = (struct osmo_sockaddr_str){};

	net->pcu_sock_wqueue_len_max = BSC_PCU_SOCK_WQUEUE_LEN_DEFAULT;
	return net;

err_free_all:
	rate_ctr_group_free(net->bts_unknown_ctrs);
err_free_bsc_ctr_stat:
	osmo_stat_item_group_free(net->bsc_statg);
err_free_bsc_ctr:
	rate_ctr_group_free(net->bsc_ctrs);
err_out:
	talloc_free(net);
	return NULL;
}

int bsc_network_alloc(void)
{
	/* initialize our data structures */
	bsc_gsmnet = bsc_network_init(tall_bsc_ctx);
	if (!bsc_gsmnet)
		return -ENOMEM;

	return 0;
}

struct gsm_bts *bsc_bts_alloc_register(struct gsm_network *net, enum gsm_bts_type type, uint8_t bsic)
{
	struct gsm_bts *bts = gsm_bts_alloc_register(net, type, bsic);
	OSMO_ASSERT(bts != NULL);

	bts->ho = ho_cfg_init(bts, net->ho);

	return bts;
}