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 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/>.
 *
 */

/*! \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/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,
};

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    " },
};

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,
};

#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));


/*! \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
 */
struct gprs_nsvc *gprs_nsvc_by_nsei(struct gprs_ns_inst *nsi, uint16_t nsei)
{
	struct gprs_nsvc *nsvc;
	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
		if (nsvc->nsei == nsei)
			return nsvc;
	}
	return NULL;
}

static struct gprs_nsvc *gprs_active_nsvc_by_nsei(struct gprs_ns_inst *nsi,
						  uint16_t nsei)
{
	struct gprs_nsvc *nsvc;
	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
		if (nsvc->nsei == nsei) {
			if (!(nsvc->state & NSE_S_BLOCKED) &&
			    nsvc->state & NSE_S_ALIVE)
				return nsvc;
		}
	}
	return NULL;
}

/* Lookup struct gprs_nsvc based on remote peer socket addr */
static struct gprs_nsvc *nsvc_by_rem_addr(struct gprs_ns_inst *nsi,
					  struct sockaddr_in *sin)
{
	struct gprs_nsvc *nsvc;
	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
		if (nsvc->ip.bts_addr.sin_addr.s_addr ==
					sin->sin_addr.s_addr &&
		    nsvc->ip.bts_addr.sin_port == sin->sin_port)
			return nsvc;
	}
	return NULL;
}

static void gprs_ns_timer_cb(void *data);

struct gprs_nsvc *gprs_nsvc_create(struct gprs_ns_inst *nsi, uint16_t nsvci)
{
	struct gprs_nsvc *nsvc;

	LOGP(DNS, LOGL_INFO, "NSVCI=%u Creating NS-VC\n", nsvci);

	nsvc = talloc_zero(nsi, struct gprs_nsvc);
	nsvc->nsvci = nsvci;
	nsvc->nsvci_is_valid = 1;
	/* before RESET procedure: BLOCKED and DEAD */
	nsvc->state = NSE_S_BLOCKED;
	nsvc->nsi = nsi;
	nsvc->timer.cb = gprs_ns_timer_cb;
	nsvc->timer.data = nsvc;
	nsvc->ctrg = rate_ctr_group_alloc(nsvc, &nsvc_ctrg_desc, nsvci);

	llist_add(&nsvc->list, &nsi->gprs_nsvcs);

	return nsvc;
}

/*! \brief Delete given NS-VC
 *  \param[in] nsvc gprs_nsvc to be deleted
 */
void gprs_nsvc_delete(struct gprs_nsvc *nsvc)
{
	if (osmo_timer_pending(&nsvc->timer))
		osmo_timer_del(&nsvc->timer);
	llist_del(&nsvc->list);
	rate_ctr_group_free(nsvc->ctrg);
	talloc_free(nsvc);
}

static void ns_osmo_signal_dispatch(struct gprs_nsvc *nsvc, unsigned int signal,
			       uint8_t cause)
{
	struct ns_signal_data nssd = {0};

	nssd.nsvc = nsvc;
	nssd.cause = cause;

	osmo_signal_dispatch(SS_L_NS, signal, &nssd);
}

static void ns_osmo_signal_dispatch_mismatch(struct gprs_nsvc *nsvc,
					     struct msgb *msg,
					     uint8_t pdu_type, uint8_t ie_type)
{
	struct ns_signal_data nssd = {0};

	nssd.nsvc     = nsvc;
	nssd.pdu_type = pdu_type;
	nssd.ie_type  = ie_type;
	nssd.msg      = msg;

	osmo_signal_dispatch(SS_L_NS, S_NS_MISMATCH, &nssd);
}

static void ns_osmo_signal_dispatch_replaced(struct gprs_nsvc *nsvc, struct gprs_nsvc *old_nsvc)
{
	struct ns_signal_data nssd = {0};

	nssd.nsvc = nsvc;
	nssd.old_nsvc = old_nsvc;

	osmo_signal_dispatch(SS_L_NS, S_NS_REPLACED, &nssd);
}

/* Section 10.3.2, Table 13 */
static const struct value_string ns_cause_str[] = {
	{ NS_CAUSE_TRANSIT_FAIL,	"Transit network failure" },
	{ NS_CAUSE_OM_INTERVENTION, 	"O&M intervention" },
	{ NS_CAUSE_EQUIP_FAIL,		"Equipment failure" },
	{ NS_CAUSE_NSVC_BLOCKED,	"NS-VC blocked" },
	{ NS_CAUSE_NSVC_UNKNOWN,	"NS-VC unknown" },
	{ NS_CAUSE_BVCI_UNKNOWN,	"BVCI unknown" },
	{ NS_CAUSE_SEM_INCORR_PDU,	"Semantically incorrect PDU" },
	{ NS_CAUSE_PDU_INCOMP_PSTATE,	"PDU not compatible with protocol state" },
	{ NS_CAUSE_PROTO_E