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client: add an optional FSM interface 

the client API is not very intuitive and requires a lot of extra
care when it is used from an osmo-fsm.

- Add an FSM that permits comfortable handling of an MGCP
  connection.

Change-Id: I887ce0c15a831dffeb6251a975337b83942af566
This commit is contained in:
Philipp Maier 2018-01-17 14:32:23 +01:00
parent df5d219f39
commit 8bda7a7766
4 changed files with 693 additions and 0 deletions
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1
include/Makefile.am
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@ -7,6 +7,7 @@ nobase_include_HEADERS = \
osmocom/legacy_mgcp/mgcp_internal.h \
osmocom/legacy_mgcp/osmux.h \
osmocom/mgcp_client/mgcp_client.h \
osmocom/mgcp_client/mgcp_client_fsm.h \
osmocom/mgcp_client/mgcp_common.h \
osmocom/mgcp/mgcp.h \
osmocom/mgcp/mgcp_common.h \

33
include/osmocom/mgcp_client/mgcp_client_fsm.h Normal file
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@ -0,0 +1,33 @@
#pragma once
#include <osmocom/mgcp_client/mgcp_common.h>
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
/*! This struct organizes the connection infromation one connection side
* (either remote or local). It is used to pass parameters (local) to the FSM
* and get responses (remote) from the FSM as pointer attached to the FSM
* event.
*
* When modifiying a connection, the endpoint and call_id members may be left
* unpopulated. The call_id field is ignored in this case. If an endpoint
* identifier is supplied it is checked against the internal state to make
* sure it is correct. */
struct mgcp_conn_peer {
/*!< RTP connection IP-Address (optional, string e.g. "127.0.0.1") */
char addr[INET_ADDRSTRLEN];
/*!< RTP connection IP-Port (optional) */
uint16_t port;
/*!< RTP endpoint */
char endpoint[MGCP_ENDPOINT_MAXLEN];
/*!< CALL ID (unique per connection) */
unsigned int call_id;
};
struct osmo_fsm_inst *mgcp_conn_create(struct mgcp_client *mgcp, struct osmo_fsm_inst *parent_fi, uint32_t parent_term_evt,
uint32_t parent_evt, struct mgcp_conn_peer *conn_peer);
int mgcp_conn_modify(struct osmo_fsm_inst *fi, uint32_t parent_evt, struct mgcp_conn_peer *conn_peer);
void mgcp_conn_delete(struct osmo_fsm_inst *fi);

1
src/libosmo-mgcp-client/Makefile.am
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@ -29,6 +29,7 @@ lib_LTLIBRARIES = \
libosmo_mgcp_client_la_SOURCES = \
mgcp_client.c \
mgcp_client_vty.c \
mgcp_client_fsm.c \
$(NULL)
libosmo_mgcp_client_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(MGCP_CLIENT_LIBVERSION)

658
src/libosmo-mgcp-client/mgcp_client_fsm.c Normal file
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@ -0,0 +1,658 @@
/* (C) 2018 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Philipp Maier
*
* 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/>.
*
*/
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/mgcp_client/mgcp_client_fsm.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/byteswap.h>
#include <arpa/inet.h>
#include <osmocom/core/logging.h>
/* Context information, this is attached to the priv pointer of the FSM and
* is also handed back when dispatcheing events to the parent FSM. This is
* purly intened and not meant to be accessible for the API user */
struct mgcp_ctx {
/* MGCP client instance that is used to interact with the MGW */
struct mgcp_client *mgcp;
/* The ID of the last pending transaction. This is used internally
* to cancel the transaction in case of an error */
mgcp_trans_id_t mgw_pending_trans;
/* Flag to mark that there is a pending transaction */
bool mgw_trans_pending;
/* Connection ID which has been assigned by he MGW */
char conn_id[MGCP_CONN_ID_LENGTH];
/* Local RTP connection info, the MGW will send outgoing traffic to the
* ip/port specified here. The Address does not have to be choosen right
* on the creation of a connection. It can always be modified later by
* the user. */
struct mgcp_conn_peer conn_peer_local;
/* Remote RTP connection info, the ip/port specified here is the address
* where the MGW expects the RTP data to be sent. This address is
* defined by soly by the MGW and can not be influenced by the user. */
struct mgcp_conn_peer conn_peer_remote;
/* The terminate flag is a way to handle cornercase sitations that
* might occur when the user runs into an error situation and sends
* a DLCX command while the FSM is waiting for a response. In this
* case the DLCX command is not executed immediately. Instead the
* terminate flag is set. When the response to from the previous
* operation is received, we know that there is a DLCX event is
* pending. The FSM then generates the EV_DLCX by itsself before
* it enters ST_READY to cause the immediate execution of the
* DLCX procedure. (If normal operations are executed too fast,
* the API functions will return an error. In general, the user
* should synchronize using the callback events) */
bool terminate;
/* Event that is sent when the current operation is completed (except
* for DLCX, there the specified parent_term_evt is sent instead) */
uint32_t parent_evt;
};
#define S(x) (1 << (x))
#define MGCP_MGW_TIMEOUT 4 /* in seconds */
#define MGCP_MGW_TIMEOUT_TIMER_NR 1
enum fsm_bsc_mgcp_states {
ST_CRCX,
ST_CRCX_RESP,
ST_READY,
ST_MDCX_RESP,
ST_DLCX_RESP,
};
enum bsc_mgcp_fsm_evt {
EV_CRCX,
EV_CRCX_RESP,
EV_MDCX,
EV_MDCX_RESP,
EV_DLCX,
EV_DLCX_RESP,
};
static struct msgb *make_crcx_msg_bind(struct mgcp_ctx *mgcp_ctx)
{
struct mgcp_msg mgcp_msg;
mgcp_msg = (struct mgcp_msg) {
.verb = MGCP_VERB_CRCX,
.presence = (MGCP_MSG_PRESENCE_ENDPOINT | MGCP_MSG_PRESENCE_CALL_ID | MGCP_MSG_PRESENCE_CONN_MODE),
.call_id = mgcp_ctx->conn_peer_local.call_id,
.conn_mode = MGCP_CONN_LOOPBACK,
};
osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_peer_local.endpoint, MGCP_ENDPOINT_MAXLEN);
return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
}
static struct msgb *make_crcx_msg_bind_connect(struct mgcp_ctx *mgcp_ctx)
{
struct mgcp_msg mgcp_msg;
mgcp_msg = (struct mgcp_msg) {
.verb = MGCP_VERB_CRCX,.presence = (MGCP_MSG_PRESENCE_ENDPOINT | MGCP_MSG_PRESENCE_CALL_ID |
MGCP_MSG_PRESENCE_CONN_MODE | MGCP_MSG_PRESENCE_AUDIO_IP |
MGCP_MSG_PRESENCE_AUDIO_PORT),
.call_id = mgcp_ctx->conn_peer_local.call_id,
.conn_mode = MGCP_CONN_RECV_SEND,
.audio_ip = mgcp_ctx->conn_peer_local.addr,
.audio_port = mgcp_ctx->conn_peer_local.port,
};
osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_peer_local.endpoint, MGCP_ENDPOINT_MAXLEN);
return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
}
static struct msgb *make_mdcx_msg(struct mgcp_ctx *mgcp_ctx)
{
struct mgcp_msg mgcp_msg;
mgcp_msg = (struct mgcp_msg) {
.verb = MGCP_VERB_MDCX,
.presence = (MGCP_MSG_PRESENCE_ENDPOINT | MGCP_MSG_PRESENCE_CALL_ID | MGCP_MSG_PRESENCE_CONN_ID |
MGCP_MSG_PRESENCE_CONN_MODE | MGCP_MSG_PRESENCE_AUDIO_IP | MGCP_MSG_PRESENCE_AUDIO_PORT),
.call_id = mgcp_ctx->conn_peer_remote.call_id,
.conn_id = mgcp_ctx->conn_id,
.conn_mode = MGCP_CONN_RECV_SEND,
.audio_ip = mgcp_ctx->conn_peer_local.addr,
.audio_port = mgcp_ctx->conn_peer_local.port,
};
osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_peer_remote.endpoint, MGCP_ENDPOINT_MAXLEN);
/* Note: We take the endpoint and the call_id from the remote
* connection info, because we can be confident that the
* information there is valid. For the local info, we explicitly
* allow endpoint and call_id to be optional */
return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
}
struct msgb *make_dlcx_msg(struct mgcp_ctx *mgcp_ctx)
{
struct mgcp_msg mgcp_msg;
mgcp_msg = (struct mgcp_msg) {
.verb = MGCP_VERB_DLCX,
.presence = (MGCP_MSG_PRESENCE_ENDPOINT | MGCP_MSG_PRESENCE_CALL_ID | MGCP_MSG_PRESENCE_CONN_ID),
.call_id = mgcp_ctx->conn_peer_remote.call_id,
.conn_id = mgcp_ctx->conn_id,
};
osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_peer_remote.endpoint, MGCP_ENDPOINT_MAXLEN);
return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
}
static void mgw_crcx_resp_cb(struct mgcp_response *r, void *priv);
static void fsm_crcx_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgcp_ctx *mgcp_ctx = data;
struct mgcp_client *mgcp;
struct msgb *msg;
int rc;
OSMO_ASSERT(mgcp_ctx);
mgcp = mgcp_ctx->mgcp;
OSMO_ASSERT(mgcp);
switch (event) {
case EV_CRCX:
LOGPFSML(fi, LOGL_DEBUG, "MGW/CRCX: creating connection on MGW endpoint:%s...\n",
mgcp_ctx->conn_peer_local.endpoint);
if (mgcp_ctx->conn_peer_local.port)
msg = make_crcx_msg_bind_connect(mgcp_ctx);
else
msg = make_crcx_msg_bind(mgcp_ctx);
OSMO_ASSERT(msg);
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
mgcp_ctx->mgw_trans_pending = true;
rc = mgcp_client_tx(mgcp, msg, mgw_crcx_resp_cb, fi);
if (rc < 0) {
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
osmo_fsm_inst_state_chg(fi, ST_CRCX_RESP, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR);
break;
default:
OSMO_ASSERT(false);
break;
}
}
static void mgw_crcx_resp_cb(struct mgcp_response *r, void *priv)
{
struct osmo_fsm_inst *fi = priv;
struct mgcp_ctx *mgcp_ctx;
int rc;
OSMO_ASSERT(fi);
mgcp_ctx = fi->priv;
OSMO_ASSERT(mgcp_ctx);
mgcp_ctx->mgw_trans_pending = false;
if (r->head.response_code != 200) {
LOGPFSML(fi, LOGL_ERROR,
"MGW/CRCX: response yields error: %d %s\n", r->head.response_code, r->head.comment);
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
osmo_strlcpy(mgcp_ctx->conn_id, r->head.conn_id, sizeof(mgcp_ctx->conn_id));
LOGPFSML(fi, LOGL_DEBUG, "MGW/CRCX: MGW responded with CI: %s\n", mgcp_ctx->conn_id);
rc = mgcp_response_parse_params(r);
if (rc) {
LOGPFSML(fi, LOGL_ERROR, "MGW/CRCX: Cannot parse CRCX response\n");
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
LOGPFSML(fi, LOGL_DEBUG, "MGW/CRCX: MGW responded with address %s:%u\n", r->audio_ip, r->audio_port);
osmo_strlcpy(mgcp_ctx->conn_peer_remote.addr, r->audio_ip, sizeof(mgcp_ctx->conn_peer_remote.addr));
mgcp_ctx->conn_peer_remote.port = r->audio_port;
if (strlen(r->head.endpoint) > 0) {
/* If we get an endpoint identifier back from the MGW, take it */
osmo_strlcpy(mgcp_ctx->conn_peer_remote.endpoint, r->head.endpoint,
sizeof(mgcp_ctx->conn_peer_remote.endpoint));
} else if (strstr(mgcp_ctx->conn_peer_local.endpoint, "*") == NULL) {
/* If we do not get an endpoint identifier back and the
* identifier we used to create the connection is not a
* wildcarded one, we take the local endpoint identifier
* instead */
osmo_strlcpy(mgcp_ctx->conn_peer_remote.endpoint, mgcp_ctx->conn_peer_local.endpoint,
sizeof(mgcp_ctx->conn_peer_local.endpoint));
} else {
LOGPFSML(fi, LOGL_ERROR, "MGW/CRCX: CRCX yielded not suitable endpoint identifier\n");
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
mgcp_ctx->conn_peer_remote.call_id = mgcp_ctx->conn_peer_local.call_id;
osmo_fsm_inst_dispatch(fi, EV_CRCX_RESP, mgcp_ctx);
}
static void fsm_crcx_resp_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgcp_ctx *mgcp_ctx = data;
OSMO_ASSERT(mgcp_ctx);
switch (event) {
case EV_CRCX_RESP:
osmo_fsm_inst_state_chg(fi, ST_READY, 0, 0);
if (mgcp_ctx->terminate) {
/* Trigger immediate DLCX if DLCX was requested while the FSM was
* busy with the previous operation */
LOGPFSML(fi, LOGL_ERROR, "MGW/CRCX: FSM was busy while DLCX was requested, executing now...\n");
osmo_fsm_inst_dispatch(fi, EV_DLCX, mgcp_ctx);
} else
osmo_fsm_inst_dispatch(fi->proc.parent, mgcp_ctx->parent_evt, &mgcp_ctx->conn_peer_remote);
break;
default:
OSMO_ASSERT(false);
break;
}
}
static void mgw_mdcx_resp_cb(struct mgcp_response *r, void *priv);
static void mgw_dlcx_resp_cb(struct mgcp_response *r, void *priv);
static void fsm_ready_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgcp_ctx *mgcp_ctx = data;
struct msgb *msg;
struct mgcp_client *mgcp;
uint32_t new_state;
int rc;
OSMO_ASSERT(mgcp_ctx);
mgcp = mgcp_ctx->mgcp;
OSMO_ASSERT(mgcp);
switch (event) {
case EV_MDCX:
msg = make_mdcx_msg(mgcp_ctx);
OSMO_ASSERT(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_mdcx_resp_cb, fi);
new_state = ST_MDCX_RESP;
break;
case EV_DLCX:
msg = make_dlcx_msg(mgcp_ctx);
OSMO_ASSERT(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_dlcx_resp_cb, fi);
new_state = ST_DLCX_RESP;
break;
default:
OSMO_ASSERT(false);
break;
}
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
mgcp_ctx->mgw_trans_pending = true;
if (rc < 0) {
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
osmo_fsm_inst_state_chg(fi, new_state, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR);
}
static void mgw_mdcx_resp_cb(struct mgcp_response *r, void *priv)
{
struct osmo_fsm_inst *fi = priv;
struct mgcp_ctx *mgcp_ctx;
int rc;
OSMO_ASSERT(fi);
mgcp_ctx = fi->priv;
OSMO_ASSERT(mgcp_ctx);
mgcp_ctx->mgw_trans_pending = false;
if (r->head.response_code != 200) {
LOGPFSML(fi, LOGL_ERROR, "MGW/MDCX: response yields error: %d %s\n", r->head.response_code,
r->head.comment);
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
rc = mgcp_response_parse_params(r);
if (rc) {
LOGPFSML(fi, LOGL_ERROR, "MGW/MDCX: Cannot parse MDCX response\n");
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
LOGPFSML(fi, LOGL_DEBUG, "MGW/MDCX: MGW responded with address %s:%u\n", r->audio_ip, r->audio_port);
osmo_strlcpy(mgcp_ctx->conn_peer_remote.addr, r->audio_ip, sizeof(mgcp_ctx->conn_peer_remote.addr));
mgcp_ctx->conn_peer_remote.port = r->audio_port;
osmo_fsm_inst_dispatch(fi, EV_MDCX_RESP, mgcp_ctx);
}
static void fsm_mdcx_resp_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgcp_ctx *mgcp_ctx = data;
OSMO_ASSERT(mgcp_ctx);
switch (event) {
case EV_MDCX_RESP:
osmo_fsm_inst_state_chg(fi, ST_READY, 0, 0);
if (mgcp_ctx->terminate) {
/* Trigger immediate DLCX if DLCX was requested while the FSM was
* busy with the previous operation */
LOGPFSML(fi, LOGL_ERROR, "MGW/MDCX: FSM was busy while DLCX was requested, executing now...\n");
osmo_fsm_inst_dispatch(fi, EV_DLCX, mgcp_ctx);
} else
osmo_fsm_inst_dispatch(fi->proc.parent, mgcp_ctx->parent_evt, &mgcp_ctx->conn_peer_remote);
break;
default:
OSMO_ASSERT(false);
break;
}
}
static void mgw_dlcx_resp_cb(struct mgcp_response *r, void *priv)
{
struct osmo_fsm_inst *fi = priv;
struct mgcp_ctx *mgcp_ctx;
OSMO_ASSERT(fi);
mgcp_ctx = fi->priv;
OSMO_ASSERT(mgcp_ctx);
mgcp_ctx->mgw_trans_pending = false;
if (r->head.response_code != 250) {
LOGPFSML(fi, LOGL_ERROR,
"MGW/DLCX: response yields error: %d %s\n", r->head.response_code, r->head.comment);
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return;
}
osmo_fsm_inst_dispatch(fi, EV_DLCX_RESP, mgcp_ctx);
}
static void fsm_dlcx_resp_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgcp_ctx *mgcp_ctx = data;
OSMO_ASSERT(mgcp_ctx);
switch (event) {
case EV_DLCX_RESP:
/* Rub out the connection identifier, since the connection
* is no longer present and we will use the connection id
* to know in error cases if the connection is still present
* or not */
memset(mgcp_ctx->conn_id, 0, sizeof(mgcp_ctx->conn_id));
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
break;
default:
OSMO_ASSERT(false);
break;
}
}
static int fsm_timeout_cb(struct osmo_fsm_inst *fi)
{
struct mgcp_ctx *mgcp_ctx = fi->priv;
struct mgcp_client *mgcp;
OSMO_ASSERT(mgcp_ctx);
mgcp = mgcp_ctx->mgcp;
OSMO_ASSERT(mgcp);
if (fi->T == MGCP_MGW_TIMEOUT_TIMER_NR) {
/* Note: We were unable to communicate with the MGW,
* unfortunately there is no meaningful action we can take
* now other than giving up. */
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
} else {
/* Note: Ther must not be any unsolicited timers
* in this FSM. If so, we have serious problem. */
OSMO_ASSERT(false);
}
return 0;
}
static void fsm_cleanup_cb(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
{
struct mgcp_ctx *mgcp_ctx = fi->priv;
struct mgcp_client *mgcp;
struct msgb *msg;
OSMO_ASSERT(mgcp_ctx);
mgcp = mgcp_ctx->mgcp;
OSMO_ASSERT(mgcp);
/* If there is still a transaction pending, cancel it now. */
if (mgcp_ctx->mgw_trans_pending)
mgcp_client_cancel(mgcp, mgcp_ctx->mgw_pending_trans);
/* Should the FSM be terminated while there are still open connections
* on the MGW, we send an unconditional DLCX to terminate the
* connection. This is not the normal case. The user should always use
* mgcp_conn_delete() to instruct the FSM to perform a graceful exit */
if (strlen(mgcp_ctx->conn_id)) {
LOGPFSML(fi, LOGL_ERROR,
"MGW/DLCX: aprupt FSM termination with connections still present, sending unconditional DLCX...\n");
msg = make_dlcx_msg(mgcp_ctx);
OSMO_ASSERT(msg);
mgcp_client_tx(mgcp, msg, NULL, NULL);
}
talloc_free(mgcp_ctx);
}
static struct osmo_fsm_state fsm_mgcp_client_states[] = {
/* Initial CRCX state. This state is immediately entered and executed
* when the FSM is started. The rationale is that we first have to
* create a connectin before we can execute other operations on that
* connection. */
[ST_CRCX] = {
.in_event_mask = S(EV_CRCX),
.out_state_mask = S(ST_CRCX_RESP),
.name = OSMO_STRINGIFY(ST_CRCX),
.action = fsm_crcx_cb,
},
/* Wait for the response to a CRCX operation, check and process the
* results, change to ST_READY afterwards. */
[ST_CRCX_RESP] = {
.in_event_mask = S(EV_CRCX_RESP),
.out_state_mask = S(ST_READY),
.name = OSMO_STRINGIFY(ST_CRCX_RESP),
.action = fsm_crcx_resp_cb,
},
/* In this idle state we wait for further operations (e.g. MDCX) that
* can be executed by the user using the API. There is no timeout in
* this state. The connection lives on until the user decides to
* terminate it (DLCX). */
[ST_READY] = {
.in_event_mask = S(EV_MDCX) | S(EV_DLCX),
.out_state_mask = S(ST_MDCX_RESP) | S(ST_DLCX_RESP),
.name = OSMO_STRINGIFY(ST_READY),
.action = fsm_ready_cb,
},
/* Wait for the response of a MDCX operation, check and process the
* results, change to ST_READY afterwards. */
[ST_MDCX_RESP] = {
.in_event_mask = S(EV_MDCX_RESP),
.out_state_mask = S(ST_READY),
.name = OSMO_STRINGIFY(ST_MDCX_RESP),
.action = fsm_mdcx_resp_cb,
},
/* Wait for the response of a DLCX operation and terminate the FSM
* normally. */
[ST_DLCX_RESP] = {
.in_event_mask = S(EV_DLCX_RESP),
.out_state_mask = 0,
.name = OSMO_STRINGIFY(ST_DLCX_RESP),
.action = fsm_dlcx_resp_cb,
},
};
static struct osmo_fsm fsm_mgcp_client = {
.name = "MGCP_CONN",
.states = fsm_mgcp_client_states,
.num_states = ARRAY_SIZE(fsm_mgcp_client_states),
.timer_cb = fsm_timeout_cb,
.cleanup = fsm_cleanup_cb,
};
/*! allocate FSM, and create a new connection on the MGW.
* \param[in] mgcp MGCP client descriptor.
* \param[in] mgcpparent_fi Parent FSM instance.
* \param[in] parent_term_evt Event to be sent to parent when terminating.
* \param[in] parent_evt Event to be sent to parent when operation is done.
* \param[in] conn_peer Connection parameters (ip, port...).
* \returns newly-allocated, initialized and registered FSM instance, NULL on error. */
struct osmo_fsm_inst *mgcp_conn_create(struct mgcp_client *mgcp, struct osmo_fsm_inst *parent_fi,
uint32_t parent_term_evt, uint32_t parent_evt, struct mgcp_conn_peer *conn_peer)
{
struct mgcp_ctx *mgcp_ctx;
static bool fsm_registered = false;
struct osmo_fsm_inst *fi;
struct in_addr ip_test;
OSMO_ASSERT(parent_fi);
OSMO_ASSERT(mgcp);
OSMO_ASSERT(conn_peer);
/* Check if IP/Port informstaion in conn info makes sense */
if (conn_peer->port && inet_aton(conn_peer->addr, &ip_test) == 0)
return NULL;
/* Register the fsm description (if not already done) */
if (fsm_registered == false) {
osmo_fsm_register(&fsm_mgcp_client);
fsm_registered = true;
}
/* Allocate and configure a new fsm instance */
fi = osmo_fsm_inst_alloc_child(&fsm_mgcp_client, parent_fi, parent_term_evt);
OSMO_ASSERT(fi);
mgcp_ctx = talloc_zero(fi, struct mgcp_ctx);
OSMO_ASSERT(mgcp_ctx);
mgcp_ctx->mgcp = mgcp;
mgcp_ctx->parent_evt = parent_evt;
memcpy(&mgcp_ctx->conn_peer_local, conn_peer, sizeof(mgcp_ctx->conn_peer_local));
fi->priv = mgcp_ctx;
/* start state machine */
OSMO_ASSERT(fi->state == ST_CRCX);
osmo_fsm_inst_dispatch(fi, EV_CRCX, mgcp_ctx);
return fi;
}
/*! modify an existing connection on the MGW.
* \param[in] fi FSM instance.
* \param[in] parent_evt Event to be sent to parent when operation is done.
* \param[in] conn_peer New connection information (ip, port...).
* \returns 0 on success, -EINVAL on error. */
int mgcp_conn_modify(struct osmo_fsm_inst *fi, uint32_t parent_evt, struct mgcp_conn_peer *conn_peer)
{
OSMO_ASSERT(fi);
struct mgcp_ctx *mgcp_ctx = fi->priv;
struct in_addr ip_test;
OSMO_ASSERT(mgcp_ctx);
OSMO_ASSERT(conn_peer);
/* The user must not issue an MDCX before the CRCX has completed,
* if this happens, it means that the parent FSM has overhead the
* parent_evt (mandatory!) and executed the MDCX without even
* waiting for the results. Another reason could be that the
* parent FSM got messed up */
OSMO_ASSERT(fi->state != ST_CRCX_RESP);
/* If the user tries to issue an MDCX while an DLCX operation is
* pending, there must be a serious problem with the paren FSM.
* Eeither the parent_term_evt (mandatory!) has been overheard,
* or the parant FSM got messed so badly that it still assumes
* a live connection although it as killed it. */
OSMO_ASSERT(fi->state != ST_DLCX_RESP);
/* Check if IP/Port parameters make sense */
if (conn_peer->port == 0)
return -EINVAL;
if (inet_aton(conn_peer->addr, &ip_test) == 0)
return -EINVAL;
/*! The user may supply an endpoint identifier in conn_peer. The
* identifier is then checked. This check is optional. Later steps do
* not depend on the endpoint identifier supplied here because it is
* already implicitly known from the CRCX phase. */
if (strlen(conn_peer->endpoint) && strcmp(conn_peer->endpoint, mgcp_ctx->conn_peer_remote.endpoint))
return -EINVAL;
/*! Note: The call-id is implicitly known from the previous CRCX and
* will not be checked even when it is set in conn_peer. */
mgcp_ctx->parent_evt = parent_evt;
memcpy(&mgcp_ctx->conn_peer_local, conn_peer, sizeof(mgcp_ctx->conn_peer_local));
osmo_fsm_inst_dispatch(fi, EV_MDCX, mgcp_ctx);
return 0;
}
/*! delete existing connection on the MGW, destroy FSM afterwards.
* \param[in] fi FSM instance. */
void mgcp_conn_delete(struct osmo_fsm_inst *fi)
{
OSMO_ASSERT(fi);
struct mgcp_ctx *mgcp_ctx = fi->priv;
OSMO_ASSERT(mgcp_ctx);
/* Unlink FSM from parent */
osmo_fsm_inst_unlink_parent(fi, NULL);
/* An error situation where the parent FSM must be killed immediately
* may lead into a situation where the DLCX can not be executed right
* at that moment because the FSM is still busy with another operation.
* In those cases we postpone the DLCX so that the FSM and the
* connections on the MGW get cleaned up gracefully. */
if (fi->state != ST_READY) {
LOGPFSML(fi, LOGL_ERROR, "MGW: operation still pending, DLCX will be postponed.\n");
mgcp_ctx->terminate = true;
return;
}
osmo_fsm_inst_dispatch(fi, EV_DLCX, mgcp_ctx);
}