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libosmocore/src/gb/gprs_ns2_vc_fsm.c

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/*! \file gprs_ns2_vc_fsm.c
* NS virtual circuit FSM implementation
* 3GPP TS 08.16 version 8.0.1 Release 1999 / ETSI TS 101 299 V8.0.1 (2002-05)
* as well as its successor 3GPP TS 48.016 */
/* (C) 2020 sysmocom - s.f.m.c. GmbH
* Author: Alexander Couzens <lynxis@fe80.eu>
*
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* 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/>.
*
*/
/* The BSS NSE only has one SGSN IP address configured, and it will use the SNS procedures
* to communicated its local IPs/ports as well as all the SGSN side IPs/ports and
* associated weights. In theory, the BSS then uses this to establish a full mesh
* of NSVCs between all BSS-side IPs/ports and SGSN-side IPs/ports */
#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/rate_ctr.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/stat_item.h>
#include <osmocom/gsm/prim.h>
#include <osmocom/gsm/tlv.h>
#include <osmocom/gprs/gprs_msgb.h>
#include <osmocom/gprs/protocol/gsm_08_16.h>
#include "gprs_ns2_internal.h"
#define S(x) (1 << (x))
struct gprs_ns2_vc_priv {
struct gprs_ns2_vc *nsvc;
/* how often the timer was triggered */
int N;
/* The initiator is responsible to UNBLOCK the VC. The BSS is usually the initiator.
* It can change during runtime. The side which blocks an unblocked side.*/
bool initiator;
bool initiate_block;
bool initiate_reset;
/* if blocked by O&M/vty */
bool om_blocked;
/* if unitdata is forwarded to the user */
bool accept_unitdata;
/* the alive counter is present in all states */
struct {
struct osmo_timer_list timer;
enum ns2_timeout mode;
int N;
struct timespec timer_started;
} alive;
};
/* The FSM covers both the VC with RESET/BLOCK and without RESET/BLOCK procedure..
*
* With RESET/BLOCK, the state should follow:
* - UNCONFIGURED -> RESET -> BLOCK -> UNBLOCKED
*
* Without RESET/BLOCK, the state should follow:
* - UNCONFIGURED -> RECOVERY -> UNBLOCKED
*
* The UNBLOCKED and TEST states are used to send ALIVE PDU using the timeout Tns-test and Tns-alive.
* UNBLOCKED -> TEST: on expire of Tns-Test, send Alive PDU.
* TEST -> UNBLOCKED: on receive of Alive_Ack PDU, go into UNBLOCKED.
*
* The RECOVERY state is used as intermediate, because a VC is only valid if it received an Alive ACK when
* not using RESET/BLOCK procedure.
*/
enum gprs_ns2_vc_state {
GPRS_NS2_ST_UNCONFIGURED,
GPRS_NS2_ST_RESET,
GPRS_NS2_ST_BLOCKED,
GPRS_NS2_ST_UNBLOCKED, /* allows sending NS_UNITDATA */
GPRS_NS2_ST_RECOVERING, /* only used when not using RESET/BLOCK procedure */
};
enum gprs_ns2_vc_event {
GPRS_NS2_EV_REQ_START,
/* received messages */
GPRS_NS2_EV_RX_RESET,
GPRS_NS2_EV_RX_RESET_ACK,
GPRS_NS2_EV_RX_UNBLOCK,
GPRS_NS2_EV_RX_UNBLOCK_ACK,
GPRS_NS2_EV_RX_BLOCK,
GPRS_NS2_EV_RX_BLOCK_ACK,
GPRS_NS2_EV_RX_ALIVE,
GPRS_NS2_EV_RX_ALIVE_ACK,
GPRS_NS2_EV_RX_STATUS,
GPRS_NS2_EV_RX_UNITDATA,
GPRS_NS2_EV_REQ_FORCE_UNCONFIGURED, /* called via vty for tests */
GPRS_NS2_EV_REQ_OM_RESET, /* vty cmd: reset */
GPRS_NS2_EV_REQ_OM_BLOCK, /* vty cmd: block */
GPRS_NS2_EV_REQ_OM_UNBLOCK, /* vty cmd: unblock*/
};
static const struct value_string ns2_vc_event_names[] = {
{ GPRS_NS2_EV_REQ_START, "REQ-START" },
{ GPRS_NS2_EV_RX_RESET, "RX-RESET" },
{ GPRS_NS2_EV_RX_RESET_ACK, "RX-RESET_ACK" },
{ GPRS_NS2_EV_RX_UNBLOCK, "RX-UNBLOCK" },
{ GPRS_NS2_EV_RX_UNBLOCK_ACK, "RX-UNBLOCK_ACK" },
{ GPRS_NS2_EV_RX_BLOCK, "RX-BLOCK" },
{ GPRS_NS2_EV_RX_BLOCK_ACK, "RX-BLOCK_ACK" },
{ GPRS_NS2_EV_RX_ALIVE, "RX-ALIVE" },
{ GPRS_NS2_EV_RX_ALIVE_ACK, "RX-ALIVE_ACK" },
{ GPRS_NS2_EV_RX_STATUS, "RX-STATUS" },
{ GPRS_NS2_EV_RX_UNITDATA, "RX-UNITDATA" },
{ GPRS_NS2_EV_REQ_FORCE_UNCONFIGURED, "REQ-FORCE_UNCONFIGURED" },
{ GPRS_NS2_EV_REQ_OM_RESET, "REQ-O&M-RESET"},
{ GPRS_NS2_EV_REQ_OM_BLOCK, "REQ-O&M-BLOCK"},
{ GPRS_NS2_EV_REQ_OM_UNBLOCK, "REQ-O&M-UNBLOCK"},
{ 0, NULL }
};
static inline struct gprs_ns2_inst *ns_inst_from_fi(struct osmo_fsm_inst *fi)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
return priv->nsvc->nse->nsi;
}
/* Start the NS-TEST procedure, either with transmitting a tx_alive,
* (start_tx_alive==true) or with starting tns-test */
static void start_test_procedure(struct osmo_fsm_inst *fi, bool start_tx_alive)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = priv->nsvc->nse->nsi;
unsigned int tout_idx;
if (osmo_timer_pending(&priv->alive.timer)) {
if (start_tx_alive) {
if (priv->alive.mode == NS_TOUT_TNS_ALIVE)
return;
} else {
if (priv->alive.mode == NS_TOUT_TNS_TEST)
return;
}
}
priv->alive.N = 0;
if (start_tx_alive) {
priv->alive.mode = NS_TOUT_TNS_ALIVE;
osmo_clock_gettime(CLOCK_MONOTONIC, &priv->alive.timer_started);
ns2_tx_alive(priv->nsvc);
tout_idx = NS_TOUT_TNS_ALIVE;
} else {
priv->alive.mode = NS_TOUT_TNS_TEST;
tout_idx = NS_TOUT_TNS_TEST;
}
LOGPFSML(fi, LOGL_DEBUG, "Starting Tns-%s of %u seconds\n",
tout_idx == NS_TOUT_TNS_ALIVE ? "alive" : "test", nsi->timeout[tout_idx]);
osmo_timer_schedule(&priv->alive.timer, nsi->timeout[tout_idx], 0);
}
static void stop_test_procedure(struct gprs_ns2_vc_priv *priv)
{
osmo_stat_item_set(osmo_stat_item_group_get_item(priv->nsvc->statg, NS_STAT_ALIVE_DELAY), 0);
osmo_timer_del(&priv->alive.timer);
}
/* how many milliseconds have expired since the last alive timer start? */
static int alive_timer_elapsed_ms(struct gprs_ns2_vc_priv *priv)
{
struct timespec now, elapsed;
if (osmo_clock_gettime(CLOCK_MONOTONIC, &now) != 0)
return 0;
timespecsub(&now, &priv->alive.timer_started, &elapsed);
return elapsed.tv_sec * 1000 + (elapsed.tv_nsec / 1000000);
}
/* we just received a NS-ALIVE-ACK; re-schedule after Tns-test */
static void recv_test_procedure(struct osmo_fsm_inst *fi)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct gprs_ns2_vc *nsvc = priv->nsvc;
/* ignoring ACKs without sending an ALIVE */
if (priv->alive.mode != NS_TOUT_TNS_ALIVE)
return;
priv->alive.mode = NS_TOUT_TNS_TEST;
osmo_timer_schedule(&priv->alive.timer, nsi->timeout[NS_TOUT_TNS_TEST], 0);
osmo_stat_item_set(osmo_stat_item_group_get_item(nsvc->statg, NS_STAT_ALIVE_DELAY),
alive_timer_elapsed_ms(priv));
}
static void alive_timeout_handler(void *data)
{
struct osmo_fsm_inst *fi = data;
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct gprs_ns2_vc_priv *priv = fi->priv;
switch (priv->alive.mode) {
case NS_TOUT_TNS_TEST:
priv->alive.mode = NS_TOUT_TNS_ALIVE;
priv->alive.N = 0;
osmo_clock_gettime(CLOCK_MONOTONIC, &priv->alive.timer_started);
ns2_tx_alive(priv->nsvc);
osmo_timer_schedule(&priv->alive.timer, nsi->timeout[NS_TOUT_TNS_ALIVE], 0);
break;
case NS_TOUT_TNS_ALIVE:
RATE_CTR_INC_NS(priv->nsvc, NS_CTR_LOST_ALIVE);
priv->alive.N++;
if (priv->alive.N <= nsi->timeout[NS_TOUT_TNS_ALIVE_RETRIES]) {
/* retransmission */
ns2_tx_alive(priv->nsvc);
osmo_timer_schedule(&priv->alive.timer, nsi->timeout[NS_TOUT_TNS_ALIVE], 0);
} else {
/* lost connection */
if (priv->nsvc->mode == GPRS_NS2_VC_MODE_BLOCKRESET) {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], 0);
} else {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RECOVERING, nsi->timeout[NS_TOUT_TNS_ALIVE], 0);
}
}
break;
default:
break;
}
}
static void ns2_st_unconfigured_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
stop_test_procedure(fi->priv);
ns2_nse_notify_unblocked(priv->nsvc, false);
}
static void ns2_st_unconfigured(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = priv->nsvc->nse->nsi;
priv->initiate_reset = priv->initiate_block = priv->initiator;
priv->om_blocked = false;
switch (event) {
case GPRS_NS2_EV_REQ_START:
switch (priv->nsvc->mode) {
case GPRS_NS2_VC_MODE_ALIVE:
if (priv->nsvc->nse->dialect == GPRS_NS2_DIALECT_SNS) {
/* In IP-SNS, the NS-VC are assumed initially alive, until the alive
* procedure should fail at some future point */
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_UNBLOCKED, 0, 0);
} else {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RECOVERING, nsi->timeout[NS_TOUT_TNS_ALIVE], NS_TOUT_TNS_ALIVE);
}
break;
case GPRS_NS2_VC_MODE_BLOCKRESET:
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], NS_TOUT_TNS_RESET);
break;
}
break;
default:
OSMO_ASSERT(0);
}
}
static void ns2_st_reset_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
if (old_state != GPRS_NS2_ST_RESET)
priv->N = 0;
priv->accept_unitdata = false;
if (priv->initiate_reset)
ns2_tx_reset(priv->nsvc, NS_CAUSE_OM_INTERVENTION);
stop_test_procedure(priv);
ns2_nse_notify_unblocked(priv->nsvc, false);
}
static void ns2_st_reset(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct gprs_ns2_vc_priv *priv = fi->priv;
if (priv->initiate_reset) {
switch (event) {
case GPRS_NS2_EV_RX_RESET:
ns2_tx_reset_ack(priv->nsvc);
/* fall-through */
case GPRS_NS2_EV_RX_RESET_ACK:
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED,
nsi->timeout[NS_TOUT_TNS_BLOCK], NS_TOUT_TNS_BLOCK);
break;
}
} else {
/* we are on the receiving end */
switch (event) {
case GPRS_NS2_EV_RX_RESET:
ns2_tx_reset_ack(priv->nsvc);
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED,
0, 0);
break;
}
}
}
static void ns2_st_blocked_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
if (old_state != GPRS_NS2_ST_BLOCKED) {
priv->N = 0;
RATE_CTR_INC_NS(priv->nsvc, NS_CTR_BLOCKED);
}
ns2_nse_notify_unblocked(priv->nsvc, false);
if (priv->om_blocked) {
/* we are already blocked after a RESET */
if (old_state == GPRS_NS2_ST_RESET) {
osmo_timer_del(&fi->timer);
} else {
ns2_tx_block(priv->nsvc, NS_CAUSE_OM_INTERVENTION);
}
} else if (priv->initiate_block) {
ns2_tx_unblock(priv->nsvc);
}
start_test_procedure(fi, true);
}
static void ns2_st_blocked(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
if (priv->om_blocked) {
switch (event) {
case GPRS_NS2_EV_RX_BLOCK_ACK:
priv->accept_unitdata = false;
osmo_timer_del(&fi->timer);
break;
case GPRS_NS2_EV_RX_BLOCK:
priv->accept_unitdata = false;
ns2_tx_block_ack(priv->nsvc);
osmo_timer_del(&fi->timer);
break;
case GPRS_NS2_EV_RX_UNBLOCK:
priv->accept_unitdata = false;
ns2_tx_block(priv->nsvc, NS_CAUSE_OM_INTERVENTION);
osmo_timer_add(&fi->timer);
break;
}
} else if (priv->initiate_block) {
switch (event) {
case GPRS_NS2_EV_RX_BLOCK:
/* TODO: BLOCK is a UNBLOCK_NACK */
ns2_tx_block_ack(priv->nsvc);
break;
case GPRS_NS2_EV_RX_UNBLOCK:
ns2_tx_unblock_ack(priv->nsvc);
/* fall through */
case GPRS_NS2_EV_RX_UNBLOCK_ACK:
priv->accept_unitdata = true;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_UNBLOCKED,
0, NS_TOUT_TNS_TEST);
break;
}
} else {
/* we are on the receiving end. The initiator who sent RESET is responsible to UNBLOCK! */
switch (event) {
case GPRS_NS2_EV_RX_BLOCK:
ns2_tx_block_ack(priv->nsvc);
break;
case GPRS_NS2_EV_RX_UNBLOCK:
ns2_tx_unblock_ack(priv->nsvc);
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_UNBLOCKED,
0, 0);
break;
}
}
}
static void ns2_st_unblocked_on_enter(struct osmo_fsm_inst *fi, uint32_t old_state)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_vc *nsvc = priv->nsvc;
struct gprs_ns2_nse *nse = nsvc->nse;
if (old_state != GPRS_NS2_ST_UNBLOCKED) {
RATE_CTR_INC_NS(nsvc, NS_CTR_UNBLOCKED);
osmo_clock_gettime(CLOCK_MONOTONIC, &nsvc->ts_alive_change);
}
priv->accept_unitdata = true;
ns2_nse_notify_unblocked(nsvc, true);
ns2_prim_status_ind(nse, nsvc, 0, GPRS_NS2_AFF_CAUSE_VC_RECOVERY);
/* the closest interpretation of the spec would start Tns-test here first,
* and only send a NS-ALIVE after Tns-test has expired (i.e. setting the
* second argument to 'false'. However, being quick in detecting unavailability
* of a NS-VC seems like a good idea */
start_test_procedure(fi, true);
}
static void ns2_st_unblocked(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
switch (event) {
case GPRS_NS2_EV_RX_UNBLOCK:
ns2_tx_unblock_ack(priv->nsvc);
break;
case GPRS_NS2_EV_RX_BLOCK:
priv->initiate_block = false;
priv->accept_unitdata = false;
ns2_tx_block_ack(priv->nsvc);
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED,
0, 2);
break;
}
}
static void ns2_st_alive(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch (event) {
case GPRS_NS2_EV_RX_ALIVE_ACK:
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_UNBLOCKED, 0, 0);
break;
}
}
static void ns2_st_alive_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
priv->alive.mode = NS_TOUT_TNS_TEST;
osmo_timer_schedule(&priv->alive.timer, nsi->timeout[NS_TOUT_TNS_TEST], 0);
if (old_state != GPRS_NS2_ST_RECOVERING)
priv->N = 0;
start_test_procedure(fi, true);
ns2_nse_notify_unblocked(priv->nsvc, false);
}
static const struct osmo_fsm_state ns2_vc_states[] = {
[GPRS_NS2_ST_UNCONFIGURED] = {
.in_event_mask = S(GPRS_NS2_EV_REQ_START),
.out_state_mask = S(GPRS_NS2_ST_RESET) |
S(GPRS_NS2_ST_RECOVERING) |
S(GPRS_NS2_ST_UNBLOCKED),
.name = "UNCONFIGURED",
.action = ns2_st_unconfigured,
.onenter = ns2_st_unconfigured_onenter,
},
[GPRS_NS2_ST_RESET] = {
.in_event_mask = S(GPRS_NS2_EV_RX_RESET_ACK) | S(GPRS_NS2_EV_RX_RESET),
.out_state_mask = S(GPRS_NS2_ST_RESET) |
S(GPRS_NS2_ST_BLOCKED) |
S(GPRS_NS2_ST_UNCONFIGURED),
.name = "RESET",
.action = ns2_st_reset,
.onenter = ns2_st_reset_onenter,
},
[GPRS_NS2_ST_BLOCKED] = {
.in_event_mask = S(GPRS_NS2_EV_RX_BLOCK) | S(GPRS_NS2_EV_RX_BLOCK_ACK) |
S(GPRS_NS2_EV_RX_UNBLOCK) | S(GPRS_NS2_EV_RX_UNBLOCK_ACK),
.out_state_mask = S(GPRS_NS2_ST_RESET) |
S(GPRS_NS2_ST_UNBLOCKED) |
S(GPRS_NS2_ST_BLOCKED) |
S(GPRS_NS2_ST_UNCONFIGURED),
.name = "BLOCKED",
.action = ns2_st_blocked,
.onenter = ns2_st_blocked_onenter,
},
[GPRS_NS2_ST_UNBLOCKED] = {
.in_event_mask = S(GPRS_NS2_EV_RX_BLOCK) | S(GPRS_NS2_EV_RX_UNBLOCK_ACK) |
S(GPRS_NS2_EV_RX_UNBLOCK),
.out_state_mask = S(GPRS_NS2_ST_RESET) | S(GPRS_NS2_ST_RECOVERING) |
S(GPRS_NS2_ST_BLOCKED) |
S(GPRS_NS2_ST_UNCONFIGURED),
.name = "UNBLOCKED",
.action = ns2_st_unblocked,
.onenter = ns2_st_unblocked_on_enter,
},
/* ST_RECOVERING is only used on VC without RESET/BLOCK */
[GPRS_NS2_ST_RECOVERING] = {
.in_event_mask = S(GPRS_NS2_EV_RX_ALIVE_ACK),
.out_state_mask = S(GPRS_NS2_ST_RECOVERING) |
S(GPRS_NS2_ST_UNBLOCKED) |
S(GPRS_NS2_ST_UNCONFIGURED),
.name = "RECOVERING",
.action = ns2_st_alive,
.onenter = ns2_st_alive_onenter,
},
};
static int ns2_vc_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct gprs_ns2_vc_priv *priv = fi->priv;
switch (fi->state) {
case GPRS_NS2_ST_RESET:
if (priv->initiate_reset) {
RATE_CTR_INC_NS(priv->nsvc, NS_CTR_LOST_RESET);
priv->N++;
if (priv->N <= nsi->timeout[NS_TOUT_TNS_RESET_RETRIES]) {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], 0);
} else {
priv->N = 0;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], 0);
}
}
break;
case GPRS_NS2_ST_BLOCKED:
if (priv->initiate_block) {
priv->N++;
if (priv->om_blocked) {
if (priv->N <= nsi->timeout[NS_TOUT_TNS_BLOCK_RETRIES]) {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED, nsi->timeout[NS_TOUT_TNS_BLOCK], 0);
} else {
/* 7.2 stop accepting data when BLOCK PDU not responded */
priv->accept_unitdata = false;
}
} else {
if (priv->N <= nsi->timeout[NS_TOUT_TNS_BLOCK_RETRIES]) {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED, nsi->timeout[NS_TOUT_TNS_BLOCK], 0);
} else {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], 0);
}
}
}
break;
case GPRS_NS2_ST_RECOVERING:
if (priv->initiate_reset) {
priv->N++;
if (priv->N <= nsi->timeout[NS_TOUT_TNS_ALIVE_RETRIES]) {
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RECOVERING, 0, 0);
} else {
priv->N = 0;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RECOVERING, 0, 0);
}
break;
}
break;
}
return 0;
}
static void ns2_recv_unitdata(struct osmo_fsm_inst *fi,
struct msgb *msg)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
struct osmo_gprs_ns2_prim nsp = {};
uint16_t bvci;
if (msgb_l2len(msg) < sizeof(*nsh) + 3) {
msgb_free(msg);
return;
}
/* TODO: 7.1: For an IP sub-network, an NS-UNITDATA PDU
* for a PTP BVC may indicate a request to change the IP endpoint
* and/or a response to a change in the IP endpoint. */
/* TODO: nsh->data[0] -> C/R only valid in IP SNS */
bvci = nsh->data[1] << 8 | nsh->data[2];
msg->l3h = &nsh->data[3];
nsp.bvci = bvci;
nsp.nsei = priv->nsvc->nse->nsei;
/* 10.3.9 NS SDU Control Bits */
if (nsh->data[0] & 0x1)
nsp.u.unitdata.change = GPRS_NS2_ENDPOINT_REQUEST_CHANGE;
osmo_prim_init(&nsp.oph, SAP_NS, GPRS_NS2_PRIM_UNIT_DATA,
PRIM_OP_INDICATION, msg);
nsi->cb(&nsp.oph, nsi->cb_data);
}
static void ns2_vc_fsm_allstate_action(struct osmo_fsm_inst *fi,
uint32_t event,
void *data)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
struct gprs_ns2_inst *nsi = ns_inst_from_fi(fi);
struct tlv_parsed *tp;
struct msgb *msg = data;
uint8_t cause;
switch (event) {
case GPRS_NS2_EV_REQ_OM_RESET:
if (priv->nsvc->mode != GPRS_NS2_VC_MODE_BLOCKRESET)
break;
/* move the FSM into reset */
if (fi->state != GPRS_NS2_ST_RESET) {
priv->initiate_reset = true;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], NS_TOUT_TNS_RESET);
}
break;
case GPRS_NS2_EV_RX_RESET:
if (priv->nsvc->mode != GPRS_NS2_VC_MODE_BLOCKRESET)
break;
/* move the FSM into reset */
if (fi->state != GPRS_NS2_ST_RESET) {
priv->initiate_reset = false;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], NS_TOUT_TNS_RESET);
}
/* pass the event down into FSM action */
ns2_st_reset(fi, event, data);
break;
case GPRS_NS2_EV_RX_ALIVE:
switch (fi->state) {
case GPRS_NS2_ST_UNCONFIGURED:
case GPRS_NS2_ST_RESET:
/* ignore ALIVE */
break;
default:
ns2_tx_alive_ack(priv->nsvc);
}
break;
case GPRS_NS2_EV_RX_ALIVE_ACK:
/* for VCs without RESET/BLOCK/UNBLOCK, the connections comes after ALIVE_ACK unblocked */
if (fi->state == GPRS_NS2_ST_RECOVERING)
ns2_st_alive(fi, event, data);
else
recv_test_procedure(fi);
break;
case GPRS_NS2_EV_RX_UNITDATA:
/* UNITDATA has to handle the release of msg.
* If send upwards (gprs_ns2_recv_unitdata) it must NOT free
* the msg, the upper layer has to do it.
* Otherwise the msg must be freed.
*/
LOG_NS_DATA(priv->nsvc, "Rx", NS_PDUT_UNITDATA, LOGL_INFO, "\n");
switch (fi->state) {
case GPRS_NS2_ST_BLOCKED:
/* 7.2.1: the BLOCKED_ACK might be lost */
if (priv->accept_unitdata) {
ns2_recv_unitdata(fi, msg);
return;
}
ns2_tx_status(priv->nsvc,
NS_CAUSE_NSVC_BLOCKED,
0, msg);
break;
/* ALIVE can receive UNITDATA if the ALIVE_ACK is lost */
case GPRS_NS2_ST_RECOVERING:
case GPRS_NS2_ST_UNBLOCKED:
ns2_recv_unitdata(fi, msg);
return;
}
msgb_free(msg);
break;
case GPRS_NS2_EV_REQ_FORCE_UNCONFIGURED:
if (fi->state != GPRS_NS2_ST_UNCONFIGURED) {
/* Force the NSVC back to its initial state */
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_UNCONFIGURED, 0, 0);
return;
}
break;
case GPRS_NS2_EV_REQ_OM_BLOCK:
/* vty cmd: block */
priv->initiate_block = true;
priv->om_blocked = true;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED, nsi->timeout[NS_TOUT_TNS_BLOCK], 0);
break;
case GPRS_NS2_EV_REQ_OM_UNBLOCK:
/* vty cmd: unblock*/
if (!priv->om_blocked)
return;
priv->om_blocked = false;
if (fi->state == GPRS_NS2_ST_BLOCKED)
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED, nsi->timeout[NS_TOUT_TNS_BLOCK], 0);
break;
case GPRS_NS2_EV_RX_STATUS:
tp = data;
cause = tlvp_val8(tp, NS_IE_CAUSE, 0);
switch (cause) {
case NS_CAUSE_NSVC_BLOCKED:
if (fi->state != GPRS_NS2_ST_BLOCKED) {
LOG_NS_SIGNAL(priv->nsvc, "Rx", NS_PDUT_STATUS, LOGL_ERROR, ": remote side reported blocked state.\n");
priv->initiate_block = false;
priv->accept_unitdata = false;
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_BLOCKED, nsi->timeout[NS_TOUT_TNS_BLOCK], 0);
}
break;
case NS_CAUSE_NSVC_UNKNOWN:
if (fi->state != GPRS_NS2_ST_RESET && fi->state != GPRS_NS2_ST_UNCONFIGURED) {
LOG_NS_SIGNAL(priv->nsvc, "Rx", NS_PDUT_STATUS, LOGL_ERROR, ": remote side reported unknown nsvc.\n");
osmo_fsm_inst_state_chg(fi, GPRS_NS2_ST_RESET, nsi->timeout[NS_TOUT_TNS_RESET], 0);
}
break;
}
break;
}
}
static void ns2_vc_fsm_clean(struct osmo_fsm_inst *fi,
enum osmo_fsm_term_cause cause)
{
struct gprs_ns2_vc_priv *priv = fi->priv;
osmo_timer_del(&priv->alive.timer);
}
static struct osmo_fsm ns2_vc_fsm = {
.name = "GPRS-NS2-VC",
.states = ns2_vc_states,
.num_states = ARRAY_SIZE(ns2_vc_states),
.allstate_event_mask = S(GPRS_NS2_EV_RX_UNITDATA) |
S(GPRS_NS2_EV_RX_RESET) |
S(GPRS_NS2_EV_RX_ALIVE) |
S(GPRS_NS2_EV_RX_ALIVE_ACK) |
S(GPRS_NS2_EV_RX_STATUS) |
S(GPRS_NS2_EV_REQ_FORCE_UNCONFIGURED) |
S(GPRS_NS2_EV_REQ_OM_RESET) |
S(GPRS_NS2_EV_REQ_OM_BLOCK) |
S(GPRS_NS2_EV_REQ_OM_UNBLOCK),
.allstate_action = ns2_vc_fsm_allstate_action,
.cleanup = ns2_vc_fsm_clean,
.timer_cb = ns2_vc_fsm_timer_cb,
.event_names = ns2_vc_event_names,
.pre_term = NULL,
.log_subsys = DLNS,
};
/*!
* \brief gprs_ns2_vc_fsm_alloc
* \param ctx
* \param vc
* \param id a char representation of the virtual curcuit
* \param initiator initiator is the site which starts the connection. Usually the BSS.
* \return NULL on error, otherwise the fsm
*/
struct osmo_fsm_inst *ns2_vc_fsm_alloc(struct gprs_ns2_vc *nsvc,
const char *id, bool initiator)
{
struct osmo_fsm_inst *fi;
struct gprs_ns2_vc_priv *priv;
fi = osmo_fsm_inst_alloc(&ns2_vc_fsm, nsvc, NULL, LOGL_DEBUG, id);
if (!fi)
return fi;
nsvc->fi = fi;
priv = fi->priv = talloc_zero(fi, struct gprs_ns2_vc_priv);
priv->nsvc = nsvc;
priv->initiator = initiator;
osmo_timer_setup(&priv->alive.timer, alive_timeout_handler, fi);
return fi;
}
/*! Start a NS-VC FSM.
* \param nsvc the virtual circuit
* \return 0 on success; negative on error */
int ns2_vc_fsm_start(struct gprs_ns2_vc *nsvc)
{
/* allows to call this function even for started nsvc by gprs_ns2_start_alive_all_nsvcs */
if (nsvc->fi->state == GPRS_NS2_ST_UNCONFIGURED)
return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_START, NULL);
return 0;
}
/*! Reset a NS-VC FSM.
* \param nsvc the virtual circuit
* \return 0 on success; negative on error */
int ns2_vc_force_unconfigured(struct gprs_ns2_vc *nsvc)
{
return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_FORCE_UNCONFIGURED, NULL);
}
/*! Block a NS-VC.
* \param nsvc the virtual circuit
* \return 0 on success; negative on error */
int ns2_vc_block(struct gprs_ns2_vc *nsvc)
{
struct gprs_ns2_vc_priv *priv = nsvc->fi->priv;
if (priv->om_blocked)
return -EALREADY;
return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_OM_BLOCK, NULL);
}
/*! Unblock a NS-VC.
* \param nsvc the virtual circuit
* \return 0 on success; negative on error */
int ns2_vc_unblock(struct gprs_ns2_vc *nsvc)
{
struct gprs_ns2_vc_priv *priv = nsvc->fi->priv;
if (!priv->om_blocked)
return -EALREADY;
return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_OM_UNBLOCK, NULL);
}
/*! Reset a NS-VC.
* \param nsvc the virtual circuit
* \return 0 on success; negative on error */
int ns2_vc_reset(struct gprs_ns2_vc *nsvc)
{
return osmo_fsm_inst_dispatch(nsvc->fi, GPRS_NS2_EV_REQ_OM_RESET, NULL);
}
/*! entry point for messages from the driver/VL
* \param nsvc virtual circuit on which the message was received
* \param msg message that was received
* \param tp parsed TLVs of the received message
* \return 0 on success; negative on error */
int ns2_vc_rx(struct gprs_ns2_vc *nsvc, struct msgb *msg, struct tlv_parsed *tp)
{
struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
struct osmo_fsm_inst *fi = nsvc->fi;
int rc = 0;
uint8_t cause;
uint16_t nsei, nsvci;
/* TODO: 7.2: on UNBLOCK/BLOCK: check if NS-VCI is correct,
* if not answer STATUS with "NS-VC unknown" */
/* TODO: handle BLOCK/UNBLOCK/ALIVE with different VCI */
if (ns2_validate(nsvc, nsh->pdu_type, msg, tp, &cause)) {
if (nsh->pdu_type != NS_PDUT_STATUS) {
rc = ns2_tx_status(nsvc, cause, 0, msg);
goto out;
}
}
if (TLVP_PRESENT(tp, NS_IE_NSEI)) {
nsei = tlvp_val16be(tp, NS_IE_NSEI);
if (nsei != nsvc->nse->nsei) {
/* 48.016 § 7.3.1 send, RESET_ACK to wrong NSVCI + ignore */
if (nsh->pdu_type == NS_PDUT_RESET)
ns2_tx_reset_ack(nsvc);
LOG_NS_SIGNAL(nsvc, "Rx", nsh->pdu_type, LOGL_ERROR, " with wrong NSEI=%05u. Ignoring PDU.\n", nsei);
goto out;
}
}
if (nsvc->nsvci_is_valid && TLVP_PRESENT(tp, NS_IE_VCI)) {
nsvci = tlvp_val16be(tp, NS_IE_VCI);
if (nsvci != nsvc->nsvci) {
/* 48.016 § 7.3.1 send RESET_ACK to wrong NSVCI + ignore */
if (nsh->pdu_type == NS_PDUT_RESET)
ns2_tx_reset_ack(nsvc);
LOG_NS_SIGNAL(nsvc, "Rx", nsh->pdu_type, LOGL_ERROR, " with wrong NSVCI=%05u. Ignoring PDU.\n", nsvci);
goto out;
}
}
switch (nsh->pdu_type) {
case NS_PDUT_RESET:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_RESET, tp);
break;
case NS_PDUT_RESET_ACK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_RESET_ACK, tp);
break;
case NS_PDUT_BLOCK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_BLOCK, tp);
break;
case NS_PDUT_BLOCK_ACK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_BLOCK_ACK, tp);
break;
case NS_PDUT_UNBLOCK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_UNBLOCK, tp);
break;
case NS_PDUT_UNBLOCK_ACK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_UNBLOCK_ACK, tp);
break;
case NS_PDUT_ALIVE:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_ALIVE, tp);
break;
case NS_PDUT_ALIVE_ACK:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_ALIVE_ACK, tp);
break;
case NS_PDUT_UNITDATA:
/* UNITDATA have to free msg because it might send the msg layer upwards */
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_UNITDATA, msg);
return 0;
case NS_PDUT_STATUS:
osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_STATUS, tp);
break;
default:
LOGPFSML(fi, LOGL_ERROR, "NSEI=%u Rx unknown NS PDU type %s\n", nsvc->nse->nsei,
get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
rc = -EINVAL;
break;
}
out:
msgb_free(msg);
return rc;
}
/*! is the given NS-VC unblocked? */
int ns2_vc_is_unblocked(struct gprs_ns2_vc *nsvc)
{
return (nsvc->fi->state == GPRS_NS2_ST_UNBLOCKED);
}
/* initialize osmo_ctx on main tread */
static __attribute__((constructor)) void on_dso_load_ctx(void)
{
OSMO_ASSERT(osmo_fsm_register(&ns2_vc_fsm) == 0);
}
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