path: root/src/gb/gprs_ns.c

/* GPRS Networks Service (NS) messages on the Gb interface
 * 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05) */

/* (C) 2009-2012 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, see <http://www.gnu.org/licenses/>.
 *
 */

/*! \addtogroup libgb
 *  @{
 */

/*! \file gprs_ns.c */

/*!
 * GPRS Networks Service (NS) messages on the Gb interface
 * 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05) 
 *
 * Some introduction into NS:  NS is used typically on top of frame relay,
 * but in the ip.access world it is encapsulated in UDP packets.  It serves
 * as an intermediate shim betwen BSSGP and the underlying medium.  It doesn't
 * do much, apart from providing congestion notification and status indication.
 *
 * Terms:
 * 	NS		Network Service
 *	NSVC		NS Virtual Connection
 *	NSEI		NS Entity Identifier
 *	NSVL		NS Virtual Link
 *	NSVLI		NS Virtual Link Identifier
 *	BVC		BSSGP Virtual Connection
 *	BVCI		BSSGP Virtual Connection Identifier
 *	NSVCG		NS Virtual Connection Goup
 *	Blocked		NS-VC cannot be used for user traffic
 *	Alive		Ability of a NS-VC to provide communication
 *
 *  There can be multiple BSSGP virtual connections over one (group of) NSVC's.  BSSGP will
 * therefore identify the BSSGP virtual connection by a BVCI passed down to NS.
 * NS then has to firgure out which NSVC's are responsible for this BVCI.
 * Those mappings are administratively configured.
 */

/* This implementation has the following limitations:
 *  o Only one NS-VC for each NSE: No load-sharing function
 *  o NSVCI 65535 and 65534 are reserved for internal use
 *  o Only UDP is supported as of now, no frame relay support
 *  o The IP Sub-Network-Service (SNS) as specified in 48.016 is not implemented
 *  o There are no BLOCK and UNBLOCK timers (yet?)
 */

#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <stdint.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include <osmocom/core/msgb.h>
#include <osmocom/gsm/tlv.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/select.h>
#include <osmocom/core/rate_ctr.h>
#include <osmocom/core/stat_item.h>
#include <osmocom/core/stats.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/signal.h>
#include <osmocom/gprs/gprs_ns.h>
#include <osmocom/gprs/gprs_bssgp.h>
#include <osmocom/gprs/gprs_ns_frgre.h>

#include "common_vty.h"

static const struct tlv_definition ns_att_tlvdef = {
	.def = {
		[NS_IE_CAUSE]	= { TLV_TYPE_TvLV, 0 },
		[NS_IE_VCI]	= { TLV_TYPE_TvLV, 0 },
		[NS_IE_PDU]	= { TLV_TYPE_TvLV, 0 },
		[NS_IE_BVCI]	= { TLV_TYPE_TvLV, 0 },
		[NS_IE_NSEI]	= { TLV_TYPE_TvLV, 0 },
	},
};

enum ns_ctr {
	NS_CTR_PKTS_IN,
	NS_CTR_PKTS_OUT,
	NS_CTR_BYTES_IN,
	NS_CTR_BYTES_OUT,
	NS_CTR_BLOCKED,
	NS_CTR_DEAD,
	NS_CTR_REPLACED,
	NS_CTR_NSEI_CHG,
	NS_CTR_INV_VCI,
	NS_CTR_INV_NSEI,
	NS_CTR_LOST_ALIVE,
	NS_CTR_LOST_RESET,
};

static const struct rate_ctr_desc nsvc_ctr_description[] = {
	{ "packets.in", "Packets at NS Level  ( In)" },
	{ "packets.out","Packets at NS Level  (Out)" },
	{ "bytes.in",	"Bytes at NS Level    ( In)" },
	{ "bytes.out",	"Bytes at NS Level    (Out)" },
	{ "blocked",	"NS-VC Block count         " },
	{ "dead",	"NS-VC gone dead count     " },
	{ "replaced",	"NS-VC replaced other count" },
	{ "nsei-chg",	"NS-VC changed NSEI count  " },
	{ "inv-nsvci",	"NS-VCI was invalid count  " },
	{ "inv-nsei",	"NSEI was invalid count    " },
	{ "lost.alive",	"ALIVE ACK missing count   " },
	{ "lost.reset",	"RESET ACK missing count   " },
};

static const struct rate_ctr_group_desc nsvc_ctrg_desc = {
	.group_name_prefix = "ns.nsvc",
	.group_description = "NSVC Peer Statistics",
	.num_ctr = ARRAY_SIZE(nsvc_ctr_description),
	.ctr_desc = nsvc_ctr_description,
	.class_id = OSMO_STATS_CLASS_PEER,
};

enum ns_stat {
	NS_STAT_ALIVE_DELAY,
};

static const struct osmo_stat_item_desc nsvc_stat_description[] = {
	{ "alive.delay", "ALIVE reponse time        ", "ms", 16, 0 },
};

static const struct osmo_stat_item_group_desc nsvc_statg_desc = {
	.group_name_prefix = "ns.nsvc",
	.group_description = "NSVC Peer Statistics",
	.num_items = ARRAY_SIZE(nsvc_stat_description),
	.item_desc = nsvc_stat_description,
	.class_id = OSMO_STATS_CLASS_PEER,
};

#define CHECK_TX_RC(rc, nsvc) \
		if (rc < 0)							\
			LOGP(DNS, LOGL_ERROR, "TX failed (%d) to peer %s\n",	\
				rc, gprs_ns_ll_str(nsvc));

struct msgb *gprs_ns_msgb_alloc(void)
{
	struct msgb *msg = msgb_alloc_headroom(NS_ALLOC_SIZE, NS_ALLOC_HEADROOM,
		"GPRS/NS");
	if (!msg) {
		LOGP(DNS, LOGL_ERROR, "Failed to allocate NS message of size %d\n",
			NS_ALLOC_SIZE);
	}
	return msg;
}


/*! \brief Lookup struct gprs_nsvc based on NSVCI
 *  \param[in] nsi NS instance in which to search
 *  \param[in] nsvci NSVCI to be searched
 *  \returns gprs_nsvc of respective NSVCI
 */
struct gprs_nsvc *gprs_nsvc_by_nsvci(struct gprs_ns_inst *nsi, uint16_t nsvci)
{
	struct gprs_nsvc *nsvc;
	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
		if (nsvc->nsvci == nsvci)
			return nsvc;
	}
	return NULL;
}

/*! \brief Lookup struct gprs_nsvc based on NSEI
 *  \param[in] nsi NS instance in which to search
 *  \param[in] nsei NSEI to be searched
 *  \returns first gprs_nsvc of respective NSEI
 */