Osmocom Remote SIM Software Suite https://osmocom.org/projects/osmo-remsim
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/* (C) 2018-2019 by Harald Welte <laforge@gnumonks.org>
*
* 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.
*
*/
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <talloc.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/fsm.h>
#include <osmocom/abis/ipa.h>
#include <osmocom/gsm/protocol/ipaccess.h>
#include "debug.h"
#include "asn1c_helpers.h"
#include "rspro_client_fsm.h"
#define S(x) (1 << (x))
#define T1_WAIT_CLIENT_CONN_RES 10
#define T2_RECONNECT 10
/***********************************************************************
* client-side FSM for a RSPRO connection to remsim-server
*
* This implements the TCP/IPA client side of an RSPRO connection between
* a logical (TCP-level) client implementation and a remote RSPRO server.
*
* 'client' and 'server' here strictly refer to RSPRO protocol roles, not
* to be confused with the remsim-client or remsim-server!
*
* Specifically, this RSPRO client FSM is used by both remsim-client and
* remsim-bankd for their RSPRO control connection to remsim-server.
***********************************************************************/
static void push_and_send(struct ipa_client_conn *ipa, struct msgb *msg_tx)
{
ipa_prepend_header_ext(msg_tx, IPAC_PROTO_EXT_RSPRO);
ipa_msg_push_header(msg_tx, IPAC_PROTO_OSMO);
ipa_client_conn_send(ipa, msg_tx);
/* msg_tx is now queued and will be freed. */
}
static int ipa_client_conn_send_rspro(struct ipa_client_conn *ipa, RsproPDU_t *rspro)
{
struct msgb *msg = rspro_enc_msg(rspro);
if (!msg) {
LOGP(DRSPRO, LOGL_ERROR, "Error encoding RSPRO: %s\n", rspro_msgt_name(rspro));
osmo_log_backtrace(DRSPRO, LOGL_ERROR);
ASN_STRUCT_FREE(asn_DEF_RsproPDU, rspro);
return -1;
}
push_and_send(ipa, msg);
return 0;
}
static int _server_conn_send_rspro(struct rspro_server_conn *srvc, RsproPDU_t *rspro)
{
LOGPFSML(srvc->fi, LOGL_DEBUG, "Tx RSPRO %s\n", rspro_msgt_name(rspro));
return ipa_client_conn_send_rspro(srvc->conn, rspro);
}
int server_conn_send_rspro(struct rspro_server_conn *srvc, RsproPDU_t *rspro)
{
if (!rspro) {
LOGPFSML(srvc->fi, LOGL_ERROR, "Attempt to transmit NULL\n");
osmo_log_backtrace(DRSPRO, LOGL_ERROR);
return -EINVAL;
}
if (osmo_fsm_inst_dispatch(srvc->fi, SRVC_E_RSPRO_TX, rspro) < 0) {
ASN_STRUCT_FREE(asn_DEF_RsproPDU, rspro);
return -EPERM;
}
return 0;
}
enum server_conn_fsm_state {
/* waiting for initial connection to remsim-server */
SRVC_ST_INIT,
/* server connection established, waiting for ClientConnectRes */
SRVC_ST_ESTABLISHED,
/* server connection established, ClientConnect succeeded */
SRVC_ST_CONNECTED,
/* connection lost, we're waiting for a re-establish */
SRVC_ST_REESTABLISH,
};
static const struct value_string server_conn_fsm_event_names[] = {
OSMO_VALUE_STRING(SRVC_E_ESTABLISH),
OSMO_VALUE_STRING(SRVC_E_DISCONNECT),
OSMO_VALUE_STRING(SRVC_E_TCP_UP),
OSMO_VALUE_STRING(SRVC_E_TCP_DOWN),
OSMO_VALUE_STRING(SRVC_E_KA_TIMEOUT),
OSMO_VALUE_STRING(SRVC_E_KA_TERMINATED),
OSMO_VALUE_STRING(SRVC_E_CLIENT_CONN_RES),
OSMO_VALUE_STRING(SRVC_E_RSPRO_TX),
{ 0, NULL }
};
static void srvc_updown_cb(struct ipa_client_conn *conn, int up)
{
struct rspro_server_conn *srvc = conn->data;
LOGPFSML(srvc->fi, LOGL_NOTICE, "RSPRO link to %s:%d %s\n",
conn->addr, conn->port, up ? "UP" : "DOWN");
osmo_fsm_inst_dispatch(srvc->fi, up ? SRVC_E_TCP_UP: SRVC_E_TCP_DOWN, 0);
}
static int srvc_read_cb(struct ipa_client_conn *conn, struct msgb *msg)
{
struct ipaccess_head *hh = (struct ipaccess_head *) msg->data;
struct ipaccess_head_ext *he = (struct ipaccess_head_ext *) msgb_l2(msg);
struct rspro_server_conn *srvc = conn->data;
RsproPDU_t *pdu;
int rc;
if (msgb_length(msg) < sizeof(*hh))
goto invalid;
msg->l2h = &hh->data[0];
switch (hh->proto) {
case IPAC_PROTO_IPACCESS:
rc = ipaccess_bts_handle_ccm(srvc->conn, &srvc->ipa_dev, msg);
if (rc < 0) {
msgb_free(msg);
break;
}
switch (hh->data[0]) {
case IPAC_MSGT_PONG:
ipa_keepalive_fsm_pong_received(srvc->keepalive_fi);
rc = 0;
break;
default:
break;
}
break;
case IPAC_PROTO_OSMO:
if (!he || msgb_l2len(msg) < sizeof(*he))
goto invalid;
msg->l2h = &he->data[0];
switch (he->proto) {
case IPAC_PROTO_EXT_RSPRO:
LOGPFSML(srvc->fi, LOGL_DEBUG, "Received RSPRO %s\n", msgb_hexdump(msg));
pdu = rspro_dec_msg(msg);
if (!pdu) {
rc = -EIO;
break;
}
rc = srvc->handle_rx(srvc, pdu);
ASN_STRUCT_FREE(asn_DEF_RsproPDU, pdu);
break;
default:
goto invalid;
}
break;
default:
goto invalid;
}
msgb_free(msg);
return rc;
invalid:
LOGPFSML(srvc->fi, LOGL_ERROR, "Error decoding PDU\n");
msgb_free(msg);
return -1;
}
static const struct ipa_keepalive_params ka_params = {
.interval = 30,
.wait_for_resp = 10,
};
static void srvc_st_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch (event) {
case SRVC_E_ESTABLISH:
default:
OSMO_ASSERT(0);
}
}
static void srvc_st_established_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
RsproPDU_t *pdu;
ipa_keepalive_fsm_start(srvc->keepalive_fi);
if (srvc->own_comp_id.type == ComponentType_remsimClient)
pdu = rspro_gen_ConnectClientReq(&srvc->own_comp_id, srvc->clslot);
else
pdu = rspro_gen_ConnectBankReq(&srvc->own_comp_id, srvc->bankd.bank_id,
srvc->bankd.num_slots);
_server_conn_send_rspro(srvc, pdu);
}
static void srvc_st_established(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
RsproPDU_t *pdu = NULL;
e_ResultCode res;
switch (event) {
case SRVC_E_TCP_DOWN:
case SRVC_E_KA_TIMEOUT:
osmo_fsm_inst_state_chg(fi, SRVC_ST_REESTABLISH, T2_RECONNECT, 2);
break;
case SRVC_E_CLIENT_CONN_RES:
pdu = data;
res = rspro_get_result(pdu);
if (res != ResultCode_ok) {
LOGPFSML(fi, LOGL_ERROR, "Rx RSPRO connectClientRes(result=%s), closing\n",
asn_enum_name(&asn_DEF_ResultCode, res));
ipa_client_conn_close(srvc->conn);
osmo_fsm_inst_dispatch(fi, SRVC_E_TCP_DOWN, NULL);
} else {
/* somehow notify the main code? */
osmo_fsm_inst_state_chg(fi, SRVC_ST_CONNECTED, 0, 0);
}
break;
default:
OSMO_ASSERT(0);
}
}
static void srvc_st_connected_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
if (fi->proc.parent)
osmo_fsm_inst_dispatch(fi->proc.parent, srvc->parent_conn_evt, NULL);
}
static void srvc_st_connected(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
RsproPDU_t *pdu = NULL;
switch (event) {
case SRVC_E_TCP_DOWN:
case SRVC_E_KA_TIMEOUT:
osmo_fsm_inst_state_chg(fi, SRVC_ST_REESTABLISH, T2_RECONNECT, 2);
break;
case SRVC_E_RSPRO_TX:
pdu = data;
_server_conn_send_rspro(srvc, pdu);
break;
default:
OSMO_ASSERT(0);
}
}
static void srvc_st_connected_onleave(struct osmo_fsm_inst *fi, uint32_t next_state)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
if (fi->proc.parent)
osmo_fsm_inst_dispatch(fi->proc.parent, srvc->parent_disc_evt, NULL);
}
static int ipa_kaepalive_timeout_cb(struct osmo_fsm_inst *ka_fi, void *conn)
{
struct osmo_fsm_inst *fi = ka_fi->proc.parent;
osmo_fsm_inst_dispatch(fi, SRVC_E_KA_TIMEOUT, NULL);
return 0; /* we will explicitly terminate it */
}
static void srvc_st_reestablish_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
int rc;
if (srvc->keepalive_fi) {
ipa_keepalive_fsm_stop(srvc->keepalive_fi);
osmo_fsm_inst_term(srvc->keepalive_fi, OSMO_FSM_TERM_REGULAR, NULL);
srvc->keepalive_fi = NULL;
}
if (srvc->conn) {
LOGPFSML(fi, LOGL_INFO, "Destroying existing connection to server\n");
ipa_client_conn_close(srvc->conn);
ipa_client_conn_destroy(srvc->conn);
srvc->conn = NULL;
}
LOGPFSML(fi, LOGL_INFO, "Creating TCP connection to server at %s:%u\n",
srvc->server_host, srvc->server_port);
srvc->conn = ipa_client_conn_create2(fi, NULL, 0, NULL, 0, srvc->server_host, srvc->server_port,
srvc_updown_cb, srvc_read_cb, NULL, srvc);
if (!srvc->conn) {
LOGPFSML(fi, LOGL_FATAL, "Unable to create socket: %s\n", strerror(errno));
exit(1);
}
srvc->keepalive_fi = ipa_client_conn_alloc_keepalive_fsm(srvc->conn, &ka_params, fi->id);
if (!srvc->keepalive_fi) {
LOGPFSM(fi, "Unable to create keepalive FSM\n");
exit(1);
}
ipa_keepalive_fsm_set_timeout_cb(srvc->keepalive_fi, ipa_kaepalive_timeout_cb);
/* ensure parent is notified once keepalive FSM instance is dying */
osmo_fsm_inst_change_parent(srvc->keepalive_fi, srvc->fi, SRVC_E_KA_TERMINATED);
/* Attempt to connect TCP socket */
rc = ipa_client_conn_open(srvc->conn);
if (rc < 0) {
LOGPFSML(fi, LOGL_FATAL, "Unable to connect RSPRO to %s:%u - %s\n",
srvc->server_host, srvc->server_port, strerror(errno));
/* FIXME: retry? Timer? Abort? */
OSMO_ASSERT(0);
}
}
static void srvc_st_reestablish(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch (event) {
case SRVC_E_TCP_UP:
osmo_fsm_inst_state_chg(fi, SRVC_ST_ESTABLISHED, T1_WAIT_CLIENT_CONN_RES, 1);
break;
case SRVC_E_TCP_DOWN:
/* wait for normal T2 call-back */
break;
default:
OSMO_ASSERT(0);
}
}
static void srvc_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
switch (event) {
case SRVC_E_ESTABLISH:
osmo_fsm_inst_state_chg(fi, SRVC_ST_REESTABLISH, T2_RECONNECT, 2);
break;
case SRVC_E_DISCONNECT:
if (srvc->keepalive_fi) {
ipa_keepalive_fsm_stop(srvc->keepalive_fi);
osmo_fsm_inst_term(srvc->keepalive_fi, OSMO_FSM_TERM_REGULAR, NULL);
srvc->keepalive_fi = NULL;
}
if (srvc->conn) {
LOGPFSML(fi, LOGL_INFO, "Destroying existing connection to server\n");
ipa_client_conn_close(srvc->conn);
ipa_client_conn_destroy(srvc->conn);
srvc->conn = NULL;
}
osmo_fsm_inst_state_chg(fi, SRVC_ST_INIT, 0, 0);
break;
default:
OSMO_ASSERT(0);
}
}
static int server_conn_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
struct rspro_server_conn *srvc = (struct rspro_server_conn *) fi->priv;
switch (fi->T) {
case 2:
/* TCP reconnect failed: retry */
osmo_fsm_inst_state_chg(fi, SRVC_ST_REESTABLISH, T2_RECONNECT, 2);
break;
case 1:
/* no ClientConnectRes received: disconnect + reconnect */
ipa_client_conn_close(srvc->conn);
osmo_fsm_inst_dispatch(fi, SRVC_E_TCP_DOWN, NULL);
break;
default:
OSMO_ASSERT(0);
}
return 0;
}
static const struct osmo_fsm_state server_conn_fsm_states[] = {
[SRVC_ST_INIT] = {
.name = "INIT",
.in_event_mask = 0, /* S(SRVC_E_ESTABLISH) via allstate */
.out_state_mask = S(SRVC_ST_INIT) | S(SRVC_ST_REESTABLISH),
.action = srvc_st_init,
},
[SRVC_ST_ESTABLISHED] = {
.name = "ESTABLISHED",
.in_event_mask = S(SRVC_E_TCP_DOWN) | S(SRVC_E_KA_TIMEOUT) | S(SRVC_E_CLIENT_CONN_RES),
.out_state_mask = S(SRVC_ST_CONNECTED) | S(SRVC_ST_REESTABLISH) | S(SRVC_ST_INIT),
.action = srvc_st_established,
.onenter = srvc_st_established_onenter,
},
[SRVC_ST_CONNECTED] = {
.name = "CONNECTED",
.in_event_mask = S(SRVC_E_TCP_DOWN) | S(SRVC_E_KA_TIMEOUT) | S(SRVC_E_RSPRO_TX),
.out_state_mask = S(SRVC_ST_REESTABLISH) | S(SRVC_ST_INIT),
.action = srvc_st_connected,
.onenter = srvc_st_connected_onenter,
.onleave = srvc_st_connected_onleave,
},
[SRVC_ST_REESTABLISH] = {
.name = "REESTABLISH",
.in_event_mask = S(SRVC_E_TCP_UP) | S(SRVC_E_TCP_DOWN),
.out_state_mask = S(SRVC_ST_ESTABLISHED) | S(SRVC_ST_REESTABLISH) | S(SRVC_ST_INIT),
.action = srvc_st_reestablish,
.onenter = srvc_st_reestablish_onenter,
},
};
struct osmo_fsm rspro_client_server_fsm = {
.name = "RSPRO_CLIENT",
.states = server_conn_fsm_states,
.num_states = ARRAY_SIZE(server_conn_fsm_states),
.allstate_event_mask = S(SRVC_E_ESTABLISH) | S(SRVC_E_DISCONNECT),
.allstate_action = srvc_allstate_action,
.timer_cb = server_conn_fsm_timer_cb,
.log_subsys = DRSPRO,
.event_names = server_conn_fsm_event_names,
};
int server_conn_fsm_alloc(void *ctx, struct rspro_server_conn *srvc)
{
struct osmo_fsm_inst *fi;
fi = osmo_fsm_inst_alloc(&rspro_client_server_fsm, ctx, srvc, LOGL_DEBUG, "server");
if (!fi)
return -1;
srvc->fi = fi;
return 0;
}
static __attribute__((constructor)) void on_dso_load(void)
{
OSMO_ASSERT(osmo_fsm_register(&rspro_client_server_fsm) == 0);
}