Hello Jenkins Builder,

I'd like you to reexamine a change.  Please visit

    https://gerrit.osmocom.org/5881

to look at the new patch set (#8).

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
---
M include/Makefile.am
A include/osmocom/mgcp_client/mgcp_client_fsm.h
M include/osmocom/mgcp_client/mgcp_client_internal.h
M src/libosmo-mgcp-client/Makefile.am
A src/libosmo-mgcp-client/mgcp_client_fsm.c
5 files changed, 670 insertions(+), 5 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-mgw refs/changes/81/5881/8

diff --git a/include/Makefile.am b/include/Makefile.am
index b52e5ea..e8fc211 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -7,6 +7,7 @@
        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 \
diff --git a/include/osmocom/mgcp_client/mgcp_client_fsm.h 
b/include/osmocom/mgcp_client/mgcp_client_fsm.h
new file mode 100644
index 0000000..a9ee876
--- /dev/null
+++ b/include/osmocom/mgcp_client/mgcp_client_fsm.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <osmocom/mgcp_client/mgcp_common.h>
+#include <osmocom/mgcp_client/mgcp_client.h>
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+
+/*! Connection information. 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 */
+struct mgcp_conn_info {
+       /*!< 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 call) */
+       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_info *conn_info);
+int mgcp_conn_modify(struct osmo_fsm_inst *fi, uint32_t parent_evt, struct 
mgcp_conn_info *conn_info);
+void mgcp_conn_delete(struct osmo_fsm_inst *fi);
diff --git a/include/osmocom/mgcp_client/mgcp_client_internal.h 
b/include/osmocom/mgcp_client/mgcp_client_internal.h
index 690a4af..a2b330e 100644
--- a/include/osmocom/mgcp_client/mgcp_client_internal.h
+++ b/include/osmocom/mgcp_client/mgcp_client_internal.h
@@ -28,8 +28,6 @@
 
 int mgcp_client_rx(struct mgcp_client *mgcp, struct msgb *msg);
 
-struct mgcp_response_pending * mgcp_client_pending_add(
-                                       struct mgcp_client *mgcp,
-                                       mgcp_trans_id_t trans_id,
-                                       mgcp_response_cb_t response_cb,
-                                       void *priv);
+struct mgcp_response_pending *mgcp_client_pending_add(struct mgcp_client *mgcp,
+                                                     mgcp_trans_id_t trans_id,
+                                                     mgcp_response_cb_t 
response_cb, void *priv);
diff --git a/src/libosmo-mgcp-client/Makefile.am 
b/src/libosmo-mgcp-client/Makefile.am
index 1e4e764..a3a920b 100644
--- a/src/libosmo-mgcp-client/Makefile.am
+++ b/src/libosmo-mgcp-client/Makefile.am
@@ -29,6 +29,7 @@
 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)
diff --git a/src/libosmo-mgcp-client/mgcp_client_fsm.c 
b/src/libosmo-mgcp-client/mgcp_client_fsm.c
new file mode 100644
index 0000000..c38a0ad
--- /dev/null
+++ b/src/libosmo-mgcp-client/mgcp_client_fsm.c
@@ -0,0 +1,637 @@
+/* (C) 2017 by sysmocom - s.f.m.c. GmbH <i...@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 Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#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_info conn_info_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_info conn_info_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,
+};
+
+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_info_local.call_id,
+               .conn_mode = MGCP_CONN_LOOPBACK,
+       };
+       osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_info_local.endpoint, 
MGCP_ENDPOINT_MAXLEN);
+
+       return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
+}
+
+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_info_local.call_id,
+               .conn_mode = MGCP_CONN_RECV_SEND,
+               .audio_ip = mgcp_ctx->conn_info_local.addr,
+               .audio_port = mgcp_ctx->conn_info_local.port,
+       };
+       osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_info_local.endpoint, 
MGCP_ENDPOINT_MAXLEN);
+
+       return mgcp_msg_gen(mgcp_ctx->mgcp, &mgcp_msg);
+}
+
+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_info_remote.call_id,
+               .conn_id = mgcp_ctx->conn_id,
+               .conn_mode = MGCP_CONN_RECV_SEND,
+               .audio_ip = mgcp_ctx->conn_info_local.addr,
+               .audio_port = mgcp_ctx->conn_info_local.port,
+       };
+       osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_info_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_info_remote.call_id,
+               .conn_id = mgcp_ctx->conn_id,
+       };
+       osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->conn_info_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_info_local.endpoint);
+
+               if (mgcp_ctx->conn_info_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_info_remote.addr, r->audio_ip, 
sizeof(mgcp_ctx->conn_info_remote.addr));
+       mgcp_ctx->conn_info_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_info_remote.endpoint, 
r->head.endpoint,
+                            sizeof(mgcp_ctx->conn_info_remote.endpoint));
+       } else if (strstr(mgcp_ctx->conn_info_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_info_remote.endpoint, 
mgcp_ctx->conn_info_local.endpoint,
+                            sizeof(mgcp_ctx->conn_info_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_info_remote.call_id = mgcp_ctx->conn_info_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_info_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_info_remote.addr, r->audio_ip, 
sizeof(mgcp_ctx->conn_info_remote.addr));
+       mgcp_ctx->conn_info_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_info_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:
+               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;
+
+       OSMO_ASSERT(mgcp_ctx);
+       mgcp = mgcp_ctx->mgcp;
+       OSMO_ASSERT(mgcp);
+
+       if (mgcp_ctx->mgw_trans_pending)
+               mgcp_client_cancel(mgcp, mgcp_ctx->mgw_pending_trans);
+
+       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_CLIENT",
+       .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_info 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_info *conn_info)
+{
+       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_info);
+
+       /* Check if IP/Port informstaion in conn info makes sense */
+       if (conn_info->port && inet_aton(conn_info->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_info_local, conn_info, 
sizeof(mgcp_ctx->conn_info_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_info 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_info *conn_info)
+{
+       OSMO_ASSERT(fi);
+       struct mgcp_ctx *mgcp_ctx = fi->priv;
+       struct in_addr ip_test;
+
+       OSMO_ASSERT(mgcp_ctx);
+       OSMO_ASSERT(conn_info);
+
+       /* 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_info->port == 0)
+               return -EINVAL;
+       if (inet_aton(conn_info->addr, &ip_test) == 0)
+               return -EINVAL;
+
+       /* The user may supply an endpoint identifier that is then checked
+        * here. This check is optional. Later steps do not depend on the
+        * endpoint identifier supplied here */
+       if (strlen(conn_info->endpoint) && strcmp(conn_info->endpoint, 
mgcp_ctx->conn_info_remote.endpoint))
+               return -EINVAL;
+
+       /* Note: The call-id is implicitly known from the previoes CRCX and
+        * will not be checked even when it is set here. */
+
+       mgcp_ctx->parent_evt = parent_evt;
+       memcpy(&mgcp_ctx->conn_info_local, conn_info, 
sizeof(mgcp_ctx->conn_info_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);
+}

-- 
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I887ce0c15a831dffeb6251a975337b83942af566
Gerrit-PatchSet: 8
Gerrit-Project: osmo-mgw
Gerrit-Branch: master
Gerrit-Owner: dexter <pma...@sysmocom.de>
Gerrit-Reviewer: Harald Welte <lafo...@gnumonks.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: dexter <pma...@sysmocom.de>

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