src/bts.cpp

/*
 * Copyright (C) 2013 by Holger Hans Peter Freyther
 *
 * 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 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 <bts.h>
#include <poll_controller.h>
#include <tbf.h>

#include <gprs_rlcmac.h>
#include <gprs_debug.h>

extern "C" {
	#include <osmocom/core/talloc.h>
	#include <osmocom/core/msgb.h>
}

#include <arpa/inet.h>

#include <string.h>

extern void *tall_pcu_ctx;

static BTS s_bts;

BTS* BTS::main_bts()
{
	return &s_bts;
}

struct gprs_rlcmac_bts *BTS::bts_data()
{
	return &m_bts;
}

struct gprs_rlcmac_bts *bts_main_data()
{
	return BTS::main_bts()->bts_data();
}

BTS::BTS()
	: m_cur_fn(0)
	, m_pollController(*this)
{
	memset(&m_bts, 0, sizeof(m_bts));
	m_bts.bts = this;
}

void BTS::set_current_frame_number(int fn)
{
	m_cur_fn = fn;
	m_pollController.expireTimedout(m_cur_fn);
}

void gprs_rlcmac_pdch::enable()
{
	/* TODO: Check if there are still allocated resources.. */
	INIT_LLIST_HEAD(&paging_list);
	m_is_enabled = 1;
}

void gprs_rlcmac_pdch::disable()
{
	/* TODO.. kick free_resources once we know the TRX/TS we are on */
	m_is_enabled = 0;
}

void gprs_rlcmac_pdch::free_resources(uint8_t trx, uint8_t ts)
{
	struct gprs_rlcmac_paging *pag;
	struct gprs_rlcmac_sba *sba, *sba2;

	/* we are not enabled. there should be no resources */
	if (!is_enabled())
		return;

	/* kick all TBF on slot */
	gprs_rlcmac_tbf::free_all(this);

	/* flush all pending paging messages */
	while ((pag = dequeue_paging()))
		talloc_free(pag);

	llist_for_each_entry_safe(sba, sba2, &gprs_rlcmac_sbas, list) {
		if (sba->trx == trx && sba->ts == ts) {
			llist_del(&sba->list);
			talloc_free(sba);
		}
	}
}

struct gprs_rlcmac_paging *gprs_rlcmac_pdch::dequeue_paging()
{
	struct gprs_rlcmac_paging *pag;

	if (llist_empty(&paging_list))
		return NULL;
	pag = llist_entry(paging_list.next, struct gprs_rlcmac_paging, list);
	llist_del(&pag->list);

	return pag;
}

struct msgb *gprs_rlcmac_pdch::packet_paging_request()
{
	struct gprs_rlcmac_paging *pag;
	struct msgb *msg;
	unsigned wp = 0, len;

	/* no paging, no message */
	pag = dequeue_paging();
	if (!pag)
		return NULL;

	LOGP(DRLCMAC, LOGL_DEBUG, "Scheduling paging\n");

	/* alloc message */
	msg = msgb_alloc(23, "pag ctrl block");
	if (!msg) {
		talloc_free(pag);
		return NULL;
	}
	bitvec *pag_vec = bitvec_alloc(23);
	if (!pag_vec) {
		msgb_free(msg);
		talloc_free(pag);
		return NULL;
	}
	wp = write_packet_paging_request(pag_vec);

	/* loop until message is full */
	while (pag) {
		/* try to add paging */
		if ((pag->identity_lv[1] & 0x07) == 4) {
			/* TMSI */
			LOGP(DRLCMAC, LOGL_DEBUG, "- TMSI=0x%08x\n",
				ntohl(*((uint32_t *)(pag->identity_lv + 1))));
			len = 1 + 1 + 1 + 32 + 2 + 1;
			if (pag->identity_lv[0] != 5) {
				LOGP(DRLCMAC, LOGL_ERROR, "TMSI paging with "
					"MI != 5 octets!\n");
				goto continue_next;
			}
		} else {
			/* MI */
			LOGP(DRLCMAC, LOGL_DEBUG, "- MI=%s\n",
				osmo_hexdump(pag->identity_lv + 1,
					pag->identity_lv[0]));
			len = 1 + 1 + 1 + 4 + (pag->identity_lv[0]<<3) + 2 + 1;
			if (pag->identity_lv[0] > 8) {
				LOGP(DRLCMAC, LOGL_ERROR, "Paging with "
					"MI > 8 octets!\n");
				goto continue_next;
			}
		}
		if (wp + len > 184) {
			LOGP(DRLCMAC, LOGL_DEBUG, "- Does not fit, so schedule "
				"next time\n");
			/* put back paging record, because does not fit */
			llist_add_tail(&pag->list, &paging_list);
			break;
		}
		write_repeated_page_info(pag_vec, wp, pag->identity_lv[0],
			pag->identity_lv + 1, pag->chan_needed);

continue_next:
		talloc_free(pag);
		pag = dequeue_paging();
	}

	bitvec_pack(pag_vec, msgb_put(msg, 23));
	RlcMacDownlink_t * mac_control_block = (RlcMacDownlink_t *)talloc_zero(tall_pcu_ctx, RlcMacDownlink_t);
	LOGP(DRLCMAC, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Paging Request +++++++++++++++++++++++++\n");
	decode_gsm_rlcmac_downlink(pag_vec, mac_control_block);
	LOGPC(DCSN1, LOGL_NOTICE, "\n");
	LOGP(DRLCMAC, LOGL_DEBUG, "------------------------- TX : Packet Paging Request -------------------------\n");
	bitvec_free(pag_vec);
	talloc_free(mac_control_block);

	return msg;
}