| /*! \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 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*/ |
| GPRS_NS2_EV_RX_BLOCK_FOREIGN, /* received a BLOCK over another NSVC */ |
| }; |
| |
| 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_FOREIGN, "RX-BLOCK_FOREIGN" }, |
| { 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->nsvc->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->nsvc->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, NULL); |
| } |
| } 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->nsvc->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: |
| ns2_tx_block_ack(priv->nsvc, NULL); |
| /* fall through */ |
| case GPRS_NS2_EV_RX_BLOCK_FOREIGN: |
| /* the BLOCK ACK for foreign BLOCK PDUs (rx over another nsvc) will be sent |
| * from the receiving nsvc */ |
| priv->accept_unitdata = false; |
| 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, NULL); |
| osmo_timer_add(&fi->timer); |
| break; |
| } |
| } else if (priv->initiate_block) { |
| switch (event) { |
| case GPRS_NS2_EV_RX_BLOCK_FOREIGN: |
| /* the block ack will be sent by the rx NSVC */ |
| break; |
| case GPRS_NS2_EV_RX_BLOCK: |
| /* TODO: BLOCK is a UNBLOCK_NACK */ |
| ns2_tx_block_ack(priv->nsvc, NULL); |
| 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_FOREIGN: |
| /* the block ack will be sent by the rx NSVC */ |
| break; |
| case GPRS_NS2_EV_RX_BLOCK: |
| ns2_tx_block_ack(priv->nsvc, NULL); |
| 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: |
| ns2_tx_block_ack(priv->nsvc, NULL); |
| /* fall through */ |
| case GPRS_NS2_EV_RX_BLOCK_FOREIGN: |
| /* the BLOCK ACK for foreign BLOCK PDUs (rx over another nsvc) will be sent |
| * from the receiving nsvc */ |
| priv->initiate_block = false; |
| priv->accept_unitdata = false; |
| 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) | |
| S(GPRS_NS2_EV_RX_BLOCK_FOREIGN), |
| .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) | S(GPRS_NS2_EV_RX_BLOCK_FOREIGN), |
| .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->nsvc->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, NULL); |
| 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->nsvc->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->nsvc->om_blocked) |
| return; |
| priv->nsvc->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->nsvc->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->nsvc->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 gprs_ns2_vc *target_nsvc = nsvc; |
| 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)) { |
| /* don't answer on a STATUS with a STATUS */ |
| if (nsh->pdu_type != NS_PDUT_STATUS) { |
| rc = ns2_tx_status(nsvc, cause, 0, msg, NULL); |
| 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 (exp: %05u, got %05u). Ignoring PDU.\n", nsvc->nse->nsei, 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 (exp: %05u, got %05u). Ignoring PDU.\n", nsvc->nsvci, nsvci); |
| goto out; |
| } else if (nsh->pdu_type == NS_PDUT_BLOCK || nsh->pdu_type == NS_PDUT_STATUS) { |
| /* this is a PDU received over a NSVC and reports a status/block for another NSVC */ |
| target_nsvc = gprs_ns2_nsvc_by_nsvci(nsvc->nse->nsi, nsvci); |
| if (!target_nsvc) { |
| LOGPFSML(fi, LOGL_ERROR, "Received a %s PDU for unknown NSVC (NSVCI %d)\n", |
| get_value_string(gprs_ns_pdu_strings, nsh->pdu_type), nsvci); |
| if (nsh->pdu_type == NS_PDUT_BLOCK) |
| ns2_tx_status(nsvc, NS_CAUSE_NSVC_UNKNOWN, 0, msg, &nsvci); |
| goto out; |
| } |
| |
| if (target_nsvc->nse != nsvc->nse) { |
| LOGPFSML(fi, LOGL_ERROR, "Received a %s PDU for a NSVC (NSVCI %d) but it belongs to a different NSE!\n", |
| get_value_string(gprs_ns_pdu_strings, nsh->pdu_type), nsvci); |
| goto out; |
| } |
| |
| /* the status/block will be passed to the nsvc/target nsvc in the switch */ |
| } else { |
| 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: |
| if (target_nsvc != nsvc) { |
| osmo_fsm_inst_dispatch(target_nsvc->fi, GPRS_NS2_EV_RX_BLOCK_FOREIGN, tp); |
| ns2_tx_block_ack(nsvc, &nsvci); |
| } else { |
| 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(target_nsvc->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); |
| } |