/* GPRS SGSN functionality */

/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
 *
 * 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.
 *
 * 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 <sys/types.h>

#include <osmocore/linuxlist.h>
#include <osmocore/talloc.h>
#include <osmocore/timer.h>
#include <openbsc/gsm_subscriber.h>
#include <openbsc/debug.h>
#include <openbsc/gprs_sgsn.h>
#include <openbsc/gprs_ns.h>
#include <openbsc/gprs_bssgp.h>

static LLIST_HEAD(sgsn_mm_ctxts);

static int ra_id_equals(const struct gprs_ra_id *id1,
			const struct gprs_ra_id *id2)
{
	return (id1->mcc == id2->mcc && id1->mnc == id2->mnc &&
		id1->lac == id2->lac && id1->rac == id2->rac);
}

/* look-up a SGSN MM context based on TLLI + RAI */
struct sgsn_mm_ctx *sgsn_mm_ctx_by_tlli(u_int32_t tlli,
					const struct gprs_ra_id *raid)
{
	struct sgsn_mm_ctx *ctx;

	llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
		if (tlli == ctx->tlli &&
		    ra_id_equals(raid, &ctx->ra))
			return ctx;
	}
	return NULL;
}

struct sgsn_mm_ctx *sgsn_mm_ctx_by_ptmsi(u_int32_t p_tmsi)
{
	struct sgsn_mm_ctx *ctx;

	llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
		if (p_tmsi == ctx->p_tmsi)
			return ctx;
	}
	return NULL;
}

struct sgsn_mm_ctx *sgsn_mm_ctx_by_imsi(const char *imsi)
{
	struct sgsn_mm_ctx *ctx;

	llist_for_each_entry(ctx, &sgsn_mm_ctxts, list) {
		if (!strcmp(imsi, ctx->imsi))
			return ctx;
	}
	return NULL;

}

/* Allocate a new SGSN MM context */
struct sgsn_mm_ctx *sgsn_mm_ctx_alloc(u_int32_t tlli,
					const struct gprs_ra_id *raid)
{
	struct sgsn_mm_ctx *ctx = talloc_zero(NULL, struct sgsn_mm_ctx);

	if (!ctx)
		return NULL;

	memcpy(&ctx->ra, raid, sizeof(ctx->ra));
	ctx->tlli = tlli;
	ctx->mm_state = GMM_DEREGISTERED;

	llist_add(&ctx->list, &sgsn_mm_ctxts);

	return ctx;
}