Osmocom Home NodeB Gateway, for attaching femtocells to the 3G CN (OsmoMSC, OsmoSGSN) https://osmocom.org/projects/osmohnbgw
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osmo-hnbgw/src/osmo-hnbgw/mgw_fsm.c

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/* (C) 2021 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.
*/
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/prim.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/byteswap.h>
#include <arpa/inet.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/sockaddr_str.h>
#include <osmocom/ranap/ranap_common.h>
#include <osmocom/ranap/ranap_common_cn.h>
#include <osmocom/ranap/ranap_common_ran.h>
#include <osmocom/ranap/ranap_msg_factory.h>
#include <osmocom/ranap/ranap_ies_defs.h>
#include <osmocom/ranap/iu_helpers.h>
#include <asn1c/asn1helpers.h>
#include <osmocom/hnbgw/hnbgw.h>
#include <osmocom/hnbgw/context_map.h>
#include <osmocom/hnbgw/ranap_rab_ass.h>
#include <osmocom/hnbgw/hnbgw_rua.h>
#include <osmocom/core/tdef.h>
#include <osmocom/hnbgw/tdefs.h>
#include <osmocom/mgcp_client/mgcp_client_endpoint_fsm.h>
/* NOTE: This implementation can only handle one RAB per hnbgw context. This simplification was made because usually
* a voice call will require only one RAB at a time. An exception may be corner cases like video calls, which we
* do not support at the moment. */
/* Send Iu Release Request, this is done in erroneous cases from which we cannot recover */
static void tx_release_req(struct hnbgw_context_map *map)
{
struct hnb_context *hnb = map->hnb_ctx;
struct hnbgw_cnlink *cn = hnb->gw->sccp.cnlink;
struct msgb *msg;
struct osmo_scu_prim *prim;
static const struct RANAP_Cause cause = {
.present = RANAP_Cause_PR_transmissionNetwork,
.choice.transmissionNetwork =
RANAP_CauseTransmissionNetwork_iu_transport_connection_failed_to_establish,
};
msg = ranap_new_msg_iu_rel_req(&cause);
msg->l2h = msg->data;
prim = (struct osmo_scu_prim *)msgb_push(msg, sizeof(*prim));
prim->u.data.conn_id = map->scu_conn_id;
osmo_prim_init(&prim->oph, SCCP_SAP_USER, OSMO_SCU_PRIM_N_DATA, PRIM_OP_REQUEST, msg);
osmo_sccp_user_sap_down(cn->sccp_user, &prim->oph);
}
#define S(x) (1 << (x))
extern int asn1_xer_print;
enum mgw_fsm_event {
MGW_EV_MGCP_OK,
MGW_EV_MGCP_FAIL,
MGW_EV_MGCP_TERM,
MGW_EV_RAB_ASS_RESP,
MGW_EV_RELEASE,
};
static const struct value_string mgw_fsm_event_names[] = {
OSMO_VALUE_STRING(MGW_EV_MGCP_OK),
OSMO_VALUE_STRING(MGW_EV_MGCP_FAIL),
OSMO_VALUE_STRING(MGW_EV_MGCP_TERM),
OSMO_VALUE_STRING(MGW_EV_RAB_ASS_RESP),
OSMO_VALUE_STRING(MGW_EV_RELEASE),
{}
};
enum mgw_fsm_state {
MGW_ST_CRCX_HNB,
MGW_ST_ASSIGN,
MGW_ST_MDCX_HNB,
MGW_ST_CRCX_MSC,
MGW_ST_ESTABLISHED,
MGW_ST_RELEASE,
MGW_ST_FAILURE,
};
struct mgw_fsm_priv {
/* Backpointer to HNBGW context */
struct hnbgw_context_map *map;
/* RAB-ID from RANAP RAB AssignmentRequest message */
uint8_t rab_id;
/* Pointers to messages and prim header we take ownership of */
ranap_message *ranap_rab_ass_req_message;
ranap_message *ranap_rab_ass_resp_message;
struct osmo_prim_hdr *ranap_rab_ass_resp_oph;
/* MGW context */
struct osmo_mgcpc_ep *mgcpc_ep;
struct osmo_mgcpc_ep_ci *mgcpc_ep_ci_hnb;
struct osmo_mgcpc_ep_ci *mgcpc_ep_ci_msc;
char msc_rtp_addr[INET6_ADDRSTRLEN];
uint16_t msc_rtp_port;
};
struct osmo_tdef_state_timeout mgw_fsm_timeouts[32] = {
[MGW_ST_CRCX_HNB] = {.T = -1001 },
[MGW_ST_ASSIGN] = {.T = -1002 },
[MGW_ST_MDCX_HNB] = {.T = -1003 },
[MGW_ST_CRCX_MSC] = {.T = -1004 },
};
#define mgw_fsm_state_chg(fi, state) \
osmo_tdef_fsm_inst_state_chg(fi, state, mgw_fsm_timeouts, mgw_fsm_T_defs, -1)
static void mgw_fsm_crcx_hnb_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
struct osmo_sockaddr addr;
struct osmo_sockaddr_str addr_str;
RANAP_RAB_AssignmentRequestIEs_t *ies;
const char *epname;
struct mgcp_conn_peer mgw_info;
int rc;
LOGPFSML(fi, LOGL_DEBUG, "RAB-AssignmentRequest received, creating HNB side call-leg on MGW...\n");
/* Parse the RAB Assignment Request now */
ies = &mgw_fsm_priv->ranap_rab_ass_req_message->msg.raB_AssignmentRequestIEs;
rc = ranap_rab_ass_req_ies_extract_inet_addr(&addr, &mgw_fsm_priv->rab_id, ies, 0);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR, "Invalid RAB-AssignmentRequest -- abort\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
rc = osmo_sockaddr_str_from_sockaddr(&addr_str, &addr.u.sas);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Invalid RTP IP-address or port in RAB-AssignmentRequest -- abort\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
osmo_strlcpy(mgw_fsm_priv->msc_rtp_addr, addr_str.ip, sizeof(mgw_fsm_priv->msc_rtp_addr));
mgw_fsm_priv->msc_rtp_port = addr_str.port;
mgw_info = (struct mgcp_conn_peer) {
.call_id = (map->rua_ctx_id << 8) | mgw_fsm_priv->rab_id,
.ptime = 20,
.conn_mode = MGCP_CONN_LOOPBACK,
};
mgw_info.codecs[0] = CODEC_IUFP;
mgw_info.codecs_len = 1;
epname = mgcp_client_rtpbridge_wildcard(map->hnb_ctx->gw->mgcp_client);
mgw_fsm_priv->mgcpc_ep =
osmo_mgcpc_ep_alloc(fi, MGW_EV_MGCP_TERM, map->hnb_ctx->gw->mgcp_client, mgw_fsm_T_defs, fi->id, "%s", epname);
mgw_fsm_priv->mgcpc_ep_ci_hnb = osmo_mgcpc_ep_ci_add(mgw_fsm_priv->mgcpc_ep, "to-HNB");
osmo_mgcpc_ep_ci_request(mgw_fsm_priv->mgcpc_ep_ci_hnb, MGCP_VERB_CRCX, &mgw_info, fi, MGW_EV_MGCP_OK,
MGW_EV_MGCP_FAIL, NULL);
}
static void mgw_fsm_crcx_hnb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
const struct mgcp_conn_peer *mgw_info;
struct osmo_sockaddr addr;
struct osmo_sockaddr_str addr_str;
RANAP_RAB_AssignmentRequestIEs_t *ies;
int rc;
switch (event) {
case MGW_EV_MGCP_OK:
mgw_info = osmo_mgcpc_ep_ci_get_rtp_info(mgw_fsm_priv->mgcpc_ep_ci_hnb);
if (!mgw_info) {
LOGPFSML(fi, LOGL_ERROR, "Got no RTP info response from MGW\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
if (strchr(mgw_info->addr, '.'))
addr_str.af = AF_INET;
else
addr_str.af = AF_INET6;
addr_str.port = mgw_info->port;
osmo_strlcpy(addr_str.ip, mgw_info->addr, sizeof(addr_str.ip));
rc = osmo_sockaddr_str_to_sockaddr(&addr_str, &addr.u.sas);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to convert RTP IP-address (%s) and Port (%u) to its binary representation\n",
mgw_info->addr, mgw_info->port);
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
ies = &mgw_fsm_priv->ranap_rab_ass_req_message->msg.raB_AssignmentRequestIEs;
rc = ranap_rab_ass_req_ies_replace_inet_addr(ies, &addr, mgw_fsm_priv->rab_id);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to replace RTP IP-address (%s) and Port (%u) in RAB-AssignmentRequest\n",
mgw_info->addr, mgw_info->port);
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
mgw_fsm_state_chg(fi, MGW_ST_ASSIGN);
return;
default:
OSMO_ASSERT(false);
}
}
static void mgw_fsm_assign_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
RANAP_RAB_AssignmentRequestIEs_t *ies;
struct msgb *msg;
ies = &mgw_fsm_priv->ranap_rab_ass_req_message->msg.raB_AssignmentRequestIEs;
msg = ranap_rab_ass_req_encode(ies);
if (!msg) {
LOGPFSML(fi, LOGL_ERROR, "failed to re-encode RAB-AssignmentRequest message\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
LOGPFSML(fi, LOGL_DEBUG, "forwarding modified RAB-AssignmentRequest to HNB\n");
rua_tx_dt(map->hnb_ctx, map->is_ps, map->rua_ctx_id, msg->data, msg->len);
}
static void mgw_fsm_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch (event) {
case MGW_EV_RAB_ASS_RESP:
mgw_fsm_state_chg(fi, MGW_ST_MDCX_HNB);
return;
default:
OSMO_ASSERT(false);
}
}
static void mgw_fsm_mdcx_hnb_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
struct hnb_context *hnb = map->hnb_ctx;
struct hnbgw_cnlink *cn = hnb->gw->sccp.cnlink;
struct mgcp_conn_peer mgw_info;
struct osmo_sockaddr addr;
struct osmo_sockaddr_str addr_str;
RANAP_RAB_AssignmentResponseIEs_t *ies;
int rc;
bool rab_failed_at_hnb;
LOGPFSML(fi, LOGL_DEBUG, "RAB-AssignmentResponse received, completing HNB side call-leg on MGW...\n");
mgw_info = (struct mgcp_conn_peer) {
.call_id = map->rua_ctx_id,
.ptime = 20,
.conn_mode = MGCP_CONN_RECV_SEND,
};
mgw_info.codecs[0] = CODEC_IUFP;
mgw_info.codecs_len = 1;
ies = &mgw_fsm_priv->ranap_rab_ass_resp_message->msg.raB_AssignmentResponseIEs;
rc = ranap_rab_ass_resp_ies_extract_inet_addr(&addr, ies, mgw_fsm_priv->rab_id);
if (rc < 0) {
rab_failed_at_hnb = ranap_rab_ass_resp_ies_check_failure(ies, mgw_fsm_priv->rab_id);
if (rab_failed_at_hnb) {
LOGPFSML(fi, LOGL_ERROR,
"The RAB-AssignmentResponse contains a RAB-FailedList, RAB-Assignment (%u) failed.\n",
mgw_fsm_priv->rab_id);
/* Forward the RAB-AssignmentResponse transparently. This will ensure that the MSC is informed
* about the problem. */
LOGPFSML(fi, LOGL_DEBUG, "forwarding unmodified RAB-AssignmentResponse to MSC\n");
rc = osmo_sccp_user_sap_down(cn->sccp_user, mgw_fsm_priv->ranap_rab_ass_resp_oph);
mgw_fsm_priv->ranap_rab_ass_resp_oph = NULL;
if (rc < 0) {
LOGPFSML(fi, LOGL_DEBUG, "failed to forward RAB-AssignmentResponse message\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
}
/* Even though this is a failure situation, we still release normally as the error is located
* at the HNB. */
osmo_fsm_inst_state_chg(fi, MGW_ST_RELEASE, 0, 0);
return;
}
/* The RAB-ID we are dealing with is not on an FailedList and we were unable to parse the response
* normally. This is a situation we cannot recover from. */
LOGPFSML(fi, LOGL_ERROR, "Failed to extract RTP IP-address and Port from RAB-AssignmentResponse\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
rc = osmo_sockaddr_str_from_sockaddr(&addr_str, &addr.u.sas);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR, "Invalid RTP IP-address or Port in RAB-AssignmentResponse\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
osmo_strlcpy(mgw_info.addr, addr_str.ip, sizeof(mgw_info.addr));
mgw_info.port = addr_str.port;
osmo_mgcpc_ep_ci_request(mgw_fsm_priv->mgcpc_ep_ci_hnb, MGCP_VERB_MDCX, &mgw_info, fi, MGW_EV_MGCP_OK,
MGW_EV_MGCP_FAIL, NULL);
}
static void mgw_fsm_mdcx_hnb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
const struct mgcp_conn_peer *mgw_info;
switch (event) {
case MGW_EV_MGCP_OK:
mgw_info = osmo_mgcpc_ep_ci_get_rtp_info(mgw_fsm_priv->mgcpc_ep_ci_hnb);
if (!mgw_info) {
LOGPFSML(fi, LOGL_ERROR, "Got no RTP info response from MGW\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
mgw_fsm_state_chg(fi, MGW_ST_CRCX_MSC);
return;
default:
OSMO_ASSERT(false);
}
}
static void mgw_fsm_crcx_msc_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
struct mgcp_conn_peer mgw_info;
LOGPFSML(fi, LOGL_DEBUG, "creating MSC side call-leg on MGW...\n");
mgw_info = (struct mgcp_conn_peer) {
.call_id = (map->rua_ctx_id << 8) | mgw_fsm_priv->rab_id,
.ptime = 20,
.port = mgw_fsm_priv->msc_rtp_port,
};
osmo_strlcpy(mgw_info.addr, mgw_fsm_priv->msc_rtp_addr, sizeof(mgw_info.addr));
mgw_info.codecs[0] = CODEC_IUFP;
mgw_info.codecs_len = 1;
mgw_fsm_priv->mgcpc_ep_ci_msc = osmo_mgcpc_ep_ci_add(mgw_fsm_priv->mgcpc_ep, "to-MSC");
osmo_mgcpc_ep_ci_request(mgw_fsm_priv->mgcpc_ep_ci_msc, MGCP_VERB_CRCX, &mgw_info, fi, MGW_EV_MGCP_OK,
MGW_EV_MGCP_FAIL, NULL);
}
static void mgw_fsm_crcx_msc(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
const struct mgcp_conn_peer *mgw_info;
struct osmo_sockaddr addr;
struct osmo_sockaddr_str addr_str;
int rc;
int msg_max_len;
RANAP_RAB_AssignmentResponseIEs_t *ies;
switch (event) {
case MGW_EV_MGCP_OK:
ies = &mgw_fsm_priv->ranap_rab_ass_resp_message->msg.raB_AssignmentResponseIEs;
mgw_info = osmo_mgcpc_ep_ci_get_rtp_info(mgw_fsm_priv->mgcpc_ep_ci_msc);
if (!mgw_info) {
LOGPFSML(fi, LOGL_ERROR, "Got no response from MGW\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
/* Replace RTP IP-Address/Port in ranap message container */
if (strchr(mgw_info->addr, '.'))
addr_str.af = AF_INET;
else
addr_str.af = AF_INET6;
addr_str.port = mgw_info->port;
osmo_strlcpy(addr_str.ip, mgw_info->addr, sizeof(addr_str.ip));
rc = osmo_sockaddr_str_to_sockaddr(&addr_str, &addr.u.sas);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to convert RTP IP-address (%s) and Port (%u) to its binary representation\n",
mgw_info->addr, mgw_info->port);
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
rc = ranap_rab_ass_resp_ies_replace_inet_addr(ies, &addr, mgw_fsm_priv->rab_id);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to replace RTP IP-address (%s) and Port (%u) in RAB-AssignmentResponse\n",
mgw_info->addr, mgw_info->port);
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
/* When the modified ranap message container is re-encoded, the resulting message might be larger then
* the original message. Ensure that there is enough room in l2h to grow. (The current implementation
* should yield a message with the same size, but there is no guarantee for that) */
msg_max_len =
msgb_l2len(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg) +
msgb_tailroom(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg);
rc = msgb_resize_area(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg,
mgw_fsm_priv->ranap_rab_ass_resp_oph->msg->l2h,
msgb_l2len(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg), msg_max_len);
OSMO_ASSERT(rc == 0);
rc = ranap_rab_ass_resp_encode(msgb_l2(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg),
msgb_l2len(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg), ies);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR, "failed to re-encode RAB-AssignmentResponse message\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
}
/* Resize l2h back to the actual message length */
rc = msgb_resize_area(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg,
mgw_fsm_priv->ranap_rab_ass_resp_oph->msg->l2h,
msgb_l2len(mgw_fsm_priv->ranap_rab_ass_resp_oph->msg), rc);
OSMO_ASSERT(rc == 0);
/* When the established state is entered, the modified RAB AssignmentResponse is forwarded to the MSC.
* The call is then established any way may stay for an indefinate amount of time in this state until
* there is an IU Release happening. */
osmo_fsm_inst_state_chg(fi, MGW_ST_ESTABLISHED, 0, 0);
return;
default:
OSMO_ASSERT(false);
}
}
static void mgw_fsm_established_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
struct osmo_prim_hdr *oph = mgw_fsm_priv->ranap_rab_ass_resp_oph;
struct hnb_context *hnb = map->hnb_ctx;
struct hnbgw_cnlink *cn = hnb->gw->sccp.cnlink;
int rc;
LOGPFSML(fi, LOGL_DEBUG, "forwarding modified RAB-AssignmentResponse to MSC\n");
rc = osmo_sccp_user_sap_down(cn->sccp_user, oph);
mgw_fsm_priv->ranap_rab_ass_resp_oph = NULL;
if (rc < 0) {
LOGPFSML(fi, LOGL_DEBUG, "failed to forward RAB-AssignmentResponse message\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
}
LOGPFSML(fi, LOGL_DEBUG, "HNB and MSC side call-legs completed!\n");
}
static void mgw_fsm_release_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
}
static void mgw_fsm_failure_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
tx_release_req(mgw_fsm_priv->map);
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
}
static void mgw_fsm_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
switch (event) {
case MGW_EV_MGCP_TERM:
mgw_fsm_priv->mgcpc_ep = NULL;
LOGPFSML(fi, LOGL_ERROR, "Media gateway failed\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
case MGW_EV_MGCP_FAIL:
LOGPFSML(fi, LOGL_ERROR, "Media gateway failed to switch RTP streams\n");
osmo_fsm_inst_state_chg(fi, MGW_ST_FAILURE, 0, 0);
return;
case MGW_EV_RELEASE:
osmo_fsm_inst_state_chg(fi, MGW_ST_RELEASE, 0, 0);
return;
default:
OSMO_ASSERT(false);
}
}
static int mgw_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
return 0;
}
static void mgw_fsm_cleanup(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct osmo_scu_prim *scu_prim;
struct msgb *scu_msg;
if (mgw_fsm_priv->ranap_rab_ass_req_message) {
ranap_ran_rx_co_free(mgw_fsm_priv->ranap_rab_ass_req_message);
talloc_free(mgw_fsm_priv->ranap_rab_ass_req_message);
mgw_fsm_priv->ranap_rab_ass_req_message = NULL;
}
if (mgw_fsm_priv->ranap_rab_ass_resp_message) {
ranap_cn_rx_co_free(mgw_fsm_priv->ranap_rab_ass_resp_message);
talloc_free(mgw_fsm_priv->ranap_rab_ass_resp_message);
mgw_fsm_priv->ranap_rab_ass_resp_message = NULL;
}
if (mgw_fsm_priv->ranap_rab_ass_resp_oph) {
scu_prim = (struct osmo_scu_prim *)mgw_fsm_priv->ranap_rab_ass_resp_oph;
scu_msg = scu_prim->oph.msg;
msgb_free(scu_msg);
mgw_fsm_priv->ranap_rab_ass_resp_oph = NULL;
}
talloc_free(mgw_fsm_priv);
}
static void mgw_fsm_pre_term(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
{
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
struct hnbgw_context_map *map = mgw_fsm_priv->map;
if (mgw_fsm_priv->mgcpc_ep) {
osmo_mgcpc_ep_clear(mgw_fsm_priv->mgcpc_ep);
mgw_fsm_priv->mgcpc_ep = NULL;
}
/* Remove FSM from the context map. This will make this FSM unreachable for events coming from outside */
map->mgw_fi = NULL;
}
static const struct osmo_fsm_state mgw_fsm_states[] = {
[MGW_ST_CRCX_HNB] = {
.name = "MGW_ST_CRCX_HNB",
.onenter = mgw_fsm_crcx_hnb_onenter,
.action = mgw_fsm_crcx_hnb,
.in_event_mask =
S(MGW_EV_MGCP_OK),
.out_state_mask =
S(MGW_ST_ASSIGN) |
S(MGW_ST_FAILURE) |
S(MGW_ST_RELEASE) |
S(MGW_ST_CRCX_HNB),
},
[MGW_ST_ASSIGN] = {
.name = "MGW_ST_ASSIGN",
.onenter = mgw_fsm_assign_onenter,
.action = mgw_fsm_assign,
.in_event_mask = S(MGW_EV_RAB_ASS_RESP),
.out_state_mask =
S(MGW_ST_MDCX_HNB) |
S(MGW_ST_FAILURE) |
S(MGW_ST_RELEASE),
},
[MGW_ST_MDCX_HNB] = {
.name = "MGW_ST_MDCX_HNB",
.onenter = mgw_fsm_mdcx_hnb_onenter,
.action = mgw_fsm_mdcx_hnb,
.in_event_mask =
S(MGW_EV_MGCP_OK),
.out_state_mask =
S(MGW_ST_CRCX_MSC) |
S(MGW_ST_FAILURE) |
S(MGW_ST_RELEASE),
},
[MGW_ST_CRCX_MSC] = {
.name = "MGW_ST_CRCX_MSC",
.onenter = mgw_fsm_crcx_msc_onenter,
.action = mgw_fsm_crcx_msc,
.in_event_mask =
S(MGW_EV_MGCP_OK),
.out_state_mask =
S(MGW_ST_ESTABLISHED) |
S(MGW_ST_FAILURE) |
S(MGW_ST_RELEASE),
},
[MGW_ST_ESTABLISHED] = {
.name = "MGW_ST_ESTABLISHED",
.onenter = mgw_fsm_established_onenter,
.in_event_mask = 0,
.out_state_mask =
S(MGW_ST_FAILURE) |
S(MGW_ST_RELEASE),
},
[MGW_ST_RELEASE] = {
.name = "MGW_ST_RELEASE",
.onenter = mgw_fsm_release_onenter,
.in_event_mask = 0,
.out_state_mask = 0,
},
[MGW_ST_FAILURE] = {
.name = "MGW_ST_FAILURE",
.onenter = mgw_fsm_failure_onenter,
.in_event_mask = 0,
.out_state_mask = 0,
},
};
static struct osmo_fsm mgw_fsm = {
.name = "mgw",
.states = mgw_fsm_states,
.num_states = ARRAY_SIZE(mgw_fsm_states),
.log_subsys = DMGW,
.event_names = mgw_fsm_event_names,
.allstate_action = mgw_fsm_allstate_action,
.allstate_event_mask = S(MGW_EV_MGCP_TERM) | S(MGW_EV_RELEASE) | S(MGW_EV_MGCP_FAIL),
.timer_cb = mgw_fsm_timer_cb,
.cleanup = mgw_fsm_cleanup,
.pre_term = mgw_fsm_pre_term,
};
/* The MSC may ask to release a specific RAB within a RAB-AssignmentRequest */
static int handle_rab_release(struct hnbgw_context_map *map, struct osmo_prim_hdr *oph, ranap_message *message)
{
bool rab_release_req;
struct osmo_fsm_inst *fi = map->mgw_fi;
struct mgw_fsm_priv *mgw_fsm_priv = fi->priv;
int rc;
/* Check if the RAB that is handled by this FSM is addressed by the release request */
rab_release_req = ranap_rab_ass_req_ies_check_release(&message->msg.raB_AssignmentRequestIEs,
mgw_fsm_priv->rab_id);
if (!rab_release_req)
return -EINVAL;
LOGPFSML(map->mgw_fi, LOGL_NOTICE, "MSC asked to release RAB-ID %u\n", mgw_fsm_priv->rab_id);
/* Forward the unmodifed RAB-AssignmentRequest to HNB, so that the HNB is informed about the RAB release as
* well */
LOGPFSML(fi, LOGL_DEBUG, "forwarding unmodified RAB-AssignmentRequest to HNB\n");
rc = rua_tx_dt(map->hnb_ctx, map->is_ps, map->rua_ctx_id, msgb_l2(oph->msg), msgb_l2len(oph->msg));
/* Release the FSM normally */
osmo_fsm_inst_state_chg(fi, MGW_ST_RELEASE, 0, 0);
return rc;
}
/*! Allocate MGW FSM and handle RANAP RAB AssignmentRequest).
* \ptmap[in] map hanbgw context map that is responsible for this call.
* \ptmap[in] oph osmo prim header with RANAP RAB AssignmentResponse (function takes no ownership).
* \ptmap[in] message ranap message container (function takes ownership).
* \returns 0 on success; negative on error. */
int handle_rab_ass_req(struct hnbgw_context_map *map, struct osmo_prim_hdr *oph, ranap_message *message)
{
static bool initialized = false;
struct mgw_fsm_priv *mgw_fsm_priv;
char fsm_name[255];
int rc;
/* Initialize FSM if not done yet */
if (!initialized) {
OSMO_ASSERT(osmo_fsm_register(&mgw_fsm) == 0);
initialized = true;
}
/* The RTP stream negotiation usually begins with a RAB-AssignmentRequest and ends with an IU-Release, however
* it may also be thet the MSC decides to release the RAB with a dedicated RAB-AssignmentRequest that contains
* a ReleaseList. In this case an FSM will already be present. */
if (map->mgw_fi) {
/* A RAB Release might be in progress, handle it */
rc = handle_rab_release(map, oph, message);
if (rc >= 0)
return rc;
LOGPFSML(map->mgw_fi, LOGL_ERROR,
"mgw_fsm_alloc_and_handle_rab_ass_req() unable to handle RAB-AssignmentRequest!\n");
osmo_fsm_inst_state_chg(map->mgw_fi, MGW_ST_FAILURE, 0, 0);
OSMO_ASSERT(map->mgw_fi == NULL);
}
/* This FSM only supports RAB assignments with a single RAB assignment only. This limitation has been taken
* into account under the assumption that voice calls typically require a single RAB only. Nevertheless, we
* will block all incoming RAB assignments that try to assign more (or less) than one RAB. */
if (ranap_rab_ass_req_ies_get_count(&message->msg.raB_AssignmentRequestIEs) != 1) {
LOGP(DMGW, LOGL_ERROR,
"mgw_fsm_alloc_and_handle_rab_ass_req() rua_ctx_id=%d, RAB-AssignmentRequest with more than one RAB assignment -- abort!\n",
map->rua_ctx_id);
tx_release_req(map);
return -1;
}
mgw_fsm_priv = talloc_zero(map, struct mgw_fsm_priv);
mgw_fsm_priv->map = map;
mgw_fsm_priv->ranap_rab_ass_req_message = message;
/* Allocate FSM */
snprintf(fsm_name, sizeof(fsm_name), "mgw-fsm-%u-%u", map->rua_ctx_id, mgw_fsm_priv->rab_id);
map->mgw_fi = osmo_fsm_inst_alloc(&mgw_fsm, map, mgw_fsm_priv, LOGL_DEBUG, fsm_name);
/* Start the FSM */
mgw_fsm_state_chg(map->mgw_fi, MGW_ST_CRCX_HNB);
return 0;
}
/*! Handlie RANAP RAB AssignmentResponse (deliver message, complete RTP stream switching).
* \ptmap[in] map hanbgw context map that is responsible for this call.
* \ptmap[in] oph osmo prim header with RANAP RAB AssignmentResponse (function takes ownership).
* \ptmap[in] message ranap message container with decoded ranap message (function takes ownership).
* \returns 0 on success; negative on error. */
int mgw_fsm_handle_rab_ass_resp(struct hnbgw_context_map *map, struct osmo_prim_hdr *oph, ranap_message *message)
{
struct mgw_fsm_priv *mgw_fsm_priv;
struct osmo_scu_prim *prim;
struct msgb *msg;
OSMO_ASSERT(oph);
if (!map->mgw_fi) {
/* NOTE: This situation is a corner-case. We may end up here when the co-located MGW caused a problem
* on the way between RANAP RAB Assignment Request and RANAP RAB Assignment Response. */
LOGP(DMGW, LOGL_ERROR,
"mgw_fsm_handle_rab_ass_resp() rua_ctx_id=%d, no MGW fsm -- sending Iu-Release-Request!\n",
map->rua_ctx_id);
/* Cleanup ranap message */
ranap_cn_rx_co_free(message);
talloc_free(message);
/* Toss RAB-AssignmentResponse */
prim = (struct osmo_scu_prim *)oph;
msg = prim->oph.msg;
msgb_free(msg);
/* Send a release request, to make sure that the MSC is aware of the problem. */
tx_release_req(map);
return -1;
}
mgw_fsm_priv = map->mgw_fi->priv;
mgw_fsm_priv->ranap_rab_ass_resp_oph = oph;
mgw_fsm_priv->ranap_rab_ass_resp_message = message;
osmo_fsm_inst_dispatch(map->mgw_fi, MGW_EV_RAB_ASS_RESP, NULL);
return 0;
}
/*! Release the FSM and clear its associated RTP streams.
* \ptmap[in] map hanbgw context map that is responsible for this call.
* \returns 0 on success; negative on error. */
int mgw_fsm_release(struct hnbgw_context_map *map)
{
if (!map->mgw_fi) {
LOGP(DMGW, LOGL_ERROR, "mgw_fsm_release() rua_ctx_id=%d, no MGW fsm -- ignored!\n", map->rua_ctx_id);
return -EINVAL;
}
osmo_fsm_inst_dispatch(map->mgw_fi, MGW_EV_RELEASE, NULL);
return 0;
}