/* (C) 2017 by sysmocom - s.f.m.c. GmbH * 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 . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "../../bscconfig.h" #define S(x) (1 << (x)) #define CONN_ID_RAN 1 #define CONN_ID_CN 2 #define MGCP_MGW_TIMEOUT 4 /* in seconds */ #define MGCP_MGW_TIMEOUT_TIMER_NR 1 #define MGCP_RAN_TIMEOUT 120 /* in seconds */ #define MGCP_RAN_TIMEOUT_TIMER_NR 2 #define MGCP_REL_TIMEOUT 60 /* in seconds */ #define MGCP_REL_TIMEOUT_TIMER_NR 3 #define MGCP_ASS_TIMEOUT 10 /* in seconds */ #define MGCP_ASS_TIMEOUT_TIMER_NR 4 /* Some internal cause codes to indicate fault condition inside the FSM */ enum msc_mgcp_cause_code { MGCP_ERR_MGW_FAIL, MGCP_ERR_MGW_INVAL_RESP, MGCP_ERR_MGW_TX_FAIL, MGCP_ERR_MGW_TIMEOUT, MGCP_ERR_UNEXP_TEARDOWN, MGCP_ERR_UNSUPP_ADDR_FMT, MGCP_ERR_RAN_TIMEOUT, MGCP_ERR_ASS_TIMEOUT, MGCP_ERR_TOOLONG, MGCP_ERR_ASSGMNT_FAIL }; /* Human readable respresentation of the faul codes, will be displayed by * handle_error() */ static const struct value_string msc_mgcp_cause_codes_names[] = { {MGCP_ERR_MGW_FAIL, "operation failed on MGW"}, {MGCP_ERR_MGW_INVAL_RESP, "invalid / unparseable response from MGW"}, {MGCP_ERR_MGW_TX_FAIL, "failed to transmit MGCP message to MGW"}, {MGCP_ERR_MGW_TIMEOUT, "request to MGW timed out"}, {MGCP_ERR_UNEXP_TEARDOWN, "unexpected connection teardown"}, {MGCP_ERR_UNSUPP_ADDR_FMT, "unsupported network address format used (RAN)"}, {MGCP_ERR_RAN_TIMEOUT, "call could not be completed in time (RAN)"}, {MGCP_ERR_ASS_TIMEOUT, "assignment could not be completed in time (RAN)"}, {MGCP_ERR_TOOLONG, "string value too long"}, {MGCP_ERR_ASSGMNT_FAIL, "assignment failure (RAN)"}, {0, NULL} }; enum fsm_msc_mgcp_states { ST_CRCX_RAN, ST_CRCX_CN, ST_CRCX_COMPL, ST_MDCX_CN, ST_MDCX_CN_COMPL, ST_MDCX_RAN, ST_MDCX_RAN_COMPL, ST_CALL, ST_HALT, }; enum msc_mgcp_fsm_evt { /* Initial event: start off the state machine */ EV_INIT, /* External event: Notify that the Assignment is complete and we * may now forward IP/Port of the remote call leg to the MGW */ EV_ASSIGN, /* External event: Notify that the Call is complete and that the * two half open connections on the MGW should now be connected */ EV_CONNECT, /* External event: Notify that the call is over and the connections * on the mgw shall be removed */ EV_TEARDOWN, /* Internal event: An error occurred that requires a controlled * teardown of the RTP connections */ EV_TEARDOWN_ERROR, /* Internal event: The mgcp_gw has sent its CRCX response for * the RAN side */ EV_CRCX_RAN_RESP, /* Internal event: The mgcp_gw has sent its CRCX response for * the CN side */ EV_CRCX_CN_RESP, /* Internal event: The mgcp_gw has sent its MDCX response for * the RAN side */ EV_MDCX_RAN_RESP, /* Internal event: The mgcp_gw has sent its MDCX response for * the CN side */ EV_MDCX_CN_RESP, /* Internal event: The mgcp_gw has sent its DLCX response for * the RAN and CN side */ EV_DLCX_ALL_RESP, }; static const struct value_string msc_mgcp_fsm_evt_names[] = { OSMO_VALUE_STRING(EV_INIT), OSMO_VALUE_STRING(EV_ASSIGN), OSMO_VALUE_STRING(EV_CONNECT), OSMO_VALUE_STRING(EV_TEARDOWN), OSMO_VALUE_STRING(EV_TEARDOWN_ERROR), OSMO_VALUE_STRING(EV_CRCX_RAN_RESP), OSMO_VALUE_STRING(EV_CRCX_CN_RESP), OSMO_VALUE_STRING(EV_MDCX_RAN_RESP), OSMO_VALUE_STRING(EV_MDCX_CN_RESP), OSMO_VALUE_STRING(EV_DLCX_ALL_RESP), {0, NULL} }; /* A general error handler function. On error we still have an interest to * remove a half open connection (if possible). This function will execute * a controlled jump to the DLCX phase. From there, the FSM will then just * continue like the call were ended normally */ #define handle_error(mgcp_ctx, cause, dlcx) _handle_error(mgcp_ctx, cause, dlcx, __FILE__, __LINE__) static void _handle_error(struct mgcp_ctx *mgcp_ctx, enum msc_mgcp_cause_code cause, bool dlcx, const char *file, int line) { bool dlcx_possible = true; struct osmo_fsm_inst *fi; struct gsm_mncc mncc; OSMO_ASSERT(mgcp_ctx); fi = mgcp_ctx->fsm; OSMO_ASSERT(fi); /* Check if the endpoint identifier is a specific endpoint identifier, * since in order to perform a DLCX we must know the specific * identifier of the endpoint we want to release. If we do not have * this information because of errornous communication we can not * perform a DLCX. */ if (strstr(mgcp_ctx->rtp_endpoint, "*")) dlcx_possible = false; LOGPFSMLSRC(mgcp_ctx->fsm, LOGL_ERROR, file, line, "%s -- graceful shutdown...\n", get_value_string(msc_mgcp_cause_codes_names, cause)); /* Request the higher layers (gsm_04_08.c) to release the call. If the * problem occured after msc_mgcp_call_release() was calls, remain * silent because we already got informed and the higher layers might * already freed their context information (trans). */ if (!mgcp_ctx->free_ctx) { mncc = (struct gsm_mncc) { .msg_type = MNCC_REL_REQ, .callref = mgcp_ctx->trans->callref, .cause = { .location = GSM48_CAUSE_LOC_PRN_S_LU, .coding = 0, /* FIXME */ .value = GSM48_CC_CAUSE_RESOURCE_UNAVAIL } }; mncc_set_cause(&mncc, GSM48_CAUSE_LOC_TRANS_NET, GSM48_CC_CAUSE_RESOURCE_UNAVAIL); mncc_tx_to_cc(mgcp_ctx->trans->net, MNCC_REL_REQ, &mncc); } /* For the shutdown we have two options. Whenever it makes sense to * send a DLCX to the MGW in order to be sure that the connection is * properly cleaned up, the dlcx flag should be set. In other cases * where a DLCX does not make sense (e.g. the MGW times out), halting * directly is the better options. In those cases, the dlcx flag * should not be set */ if (dlcx && dlcx_possible) { /* Fast-forward the FSM into call state. In this state the FSM * expects either an EV_TEARDOWN or an EV_TEARDOWN_ERROR. When * one of the two events is received a DLCX will be send to * the MGW. After that. The FSM automatically halts but will * still expect a call msc_mgcp_call_release() to be freed * completely */ osmo_fsm_inst_state_chg(fi, ST_CALL, 0, 0); osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_TEARDOWN_ERROR, mgcp_ctx); } else { /* Halt the state machine immediately. The FSM will not be * freed yet, we stil require the higher layers to call * msc_mgcp_call_release() */ osmo_fsm_inst_state_chg(fi, ST_HALT, 0, 0); osmo_fsm_inst_dispatch(fi, EV_TEARDOWN_ERROR, mgcp_ctx); } } /* Timer callback to shut down in case of connectivity problems */ 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) { /* We were unable to communicate with the MGW, unfortunately * there is no meaningful action we can take now other than * giving up. */ /* Cancel the transaction that timed out */ mgcp_client_cancel(mgcp, mgcp_ctx->mgw_pending_trans); /* halt of the FSM */ handle_error(mgcp_ctx, MGCP_ERR_MGW_TIMEOUT, false); } else if (fi->T == MGCP_RAN_TIMEOUT_TIMER_NR) { /* If the logic that controls the RAN is unable to negotiate a * connection, we presumably still have a working connection to * the MGW, we will try to shut down gracefully. */ handle_error(mgcp_ctx, MGCP_ERR_RAN_TIMEOUT, true); } else if (fi->T == MGCP_REL_TIMEOUT_TIMER_NR) { /* Under normal conditions, the MSC logic should always command * to release the call at some point. However, the release may * be missing due to errors in the MSC logic and we may have * reached ST_HALT because of cascading errors and timeouts. In * this and only in this case we will allow ST_HALT to free all * context information on its own authority. */ mgcp_ctx->free_ctx = true; /* Initiate self destruction of the FSM */ osmo_fsm_inst_state_chg(fi, ST_HALT, 0, 0); osmo_fsm_inst_dispatch(fi, EV_TEARDOWN, mgcp_ctx); } else if (fi->T == MGCP_ASS_TIMEOUT_TIMER_NR) { /* There may be rare cases in which the MSC is unable to * complete the call assignment */ handle_error(mgcp_ctx, MGCP_ERR_ASS_TIMEOUT, true); } else { /* Ther must not be any unsolicited timers in this FSM. If so, * we have serious problem. */ OSMO_ASSERT(false); } return 0; } static void mgw_crcx_ran_resp_cb(struct mgcp_response *r, void *priv); /* Callback for ST_CRCX_RAN: Send CRCX for RAN side to MGW */ static void fsm_crcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct mgcp_client *mgcp; struct mgcp_msg mgcp_msg; struct msgb *msg; int rc; struct gsm_trans *trans; struct ran_conn *conn; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); /* NOTE: In case of error, we will not be able to perform any DLCX * operation because until this point we do not have requested any * endpoint yet. */ LOGPFSML(fi, LOGL_DEBUG, "CRCX/RAN: creating connection for the RAN side on MGW endpoint:%s...\n", mgcp_ctx->rtp_endpoint); /* Generate MGCP message string */ 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->call_id, .conn_mode = MGCP_CONN_RECV_ONLY }; if (osmo_strlcpy(mgcp_msg.endpoint, mgcp_client_rtpbridge_wildcard(mgcp), sizeof(mgcp_msg.endpoint)) >= MGCP_ENDPOINT_MAXLEN) { handle_error(mgcp_ctx, MGCP_ERR_TOOLONG, false); return; } /* HACK: We put the connection in loopback mode at the beginnig to * trick the hNodeB into doing the IuUP negotiation with itself. * This is a hack we need because osmo-mgw does not support IuUP yet, see OS#2459. */ #ifdef BUILD_IU if (conn->via_ran == OSMO_RAT_UTRAN_IU) mgcp_msg.conn_mode = MGCP_CONN_LOOPBACK; #endif msg = mgcp_msg_gen(mgcp, &mgcp_msg); OSMO_ASSERT(msg); /* Transmit MGCP message to MGW */ mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg); rc = mgcp_client_tx(mgcp, msg, mgw_crcx_ran_resp_cb, mgcp_ctx); if (rc < 0) { handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, false); return; } osmo_fsm_inst_state_chg(fi, ST_CRCX_CN, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR); } /* Callback for MGCP-Client: handle response for RAN associated CRCX */ static void mgw_crcx_ran_resp_cb(struct mgcp_response *r, void *priv) { struct mgcp_ctx *mgcp_ctx = priv; int rc; struct gsm_trans *trans; struct ran_conn *conn; /* NOTE: In case of error, we will not be able to perform any DLCX * operation because until we either get a parseable message that * contains an error code (no endpoint is seized in those cases) * or we get an unparseable message. In this case we can not be * sure, but we also can not draw any assumptions from unparseable * messages. */ OSMO_ASSERT(mgcp_ctx); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); if (r->head.response_code != 200) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/RAN: response yields error: %d %s\n", r->head.response_code, r->head.comment); handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, false); return; } /* memorize connection identifier and specific endpoint id */ osmo_strlcpy(mgcp_ctx->conn_id_ran, r->head.conn_id, sizeof(mgcp_ctx->conn_id_ran)); LOGPFSML(mgcp_ctx->fsm, LOGL_DEBUG, "CRCX/RAN: MGW responded with CI: %s\n", mgcp_ctx->conn_id_ran); osmo_strlcpy(mgcp_ctx->rtp_endpoint, r->head.endpoint, sizeof(mgcp_ctx->rtp_endpoint)); LOGPFSML(mgcp_ctx->fsm, LOGL_DEBUG, "CRCX/RAN: MGW assigned endpoint: %s\n", mgcp_ctx->rtp_endpoint); rc = mgcp_response_parse_params(r); if (rc) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/RAN: Cannot parse response\n"); handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP, false); return; } LOGPFSML(mgcp_ctx->fsm, LOGL_DEBUG, "CRCX/RAN: MGW responded with address %s:%u\n", r->audio_ip, r->audio_port); conn->rtp.local_port_ran = r->audio_port; osmo_strlcpy(conn->rtp.local_addr_ran, r->audio_ip, sizeof(conn->rtp.local_addr_ran)); /* Notify the FSM that we got the response. */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_CRCX_RAN_RESP, mgcp_ctx); } static void mgw_crcx_cn_resp_cb(struct mgcp_response *r, void *priv); /* Callback for ST_CRCX_CN: check MGW response and send CRCX for CN side to MGW */ static void fsm_crcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct mgcp_client *mgcp; struct mgcp_msg mgcp_msg; struct msgb *msg; int rc; struct gsm_trans *trans; struct ran_conn *conn; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); switch (event) { case EV_CRCX_RAN_RESP: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } LOGPFSML(fi, LOGL_DEBUG, "CRCX/CN creating connection for the CN side on MGW endpoint:%s...\n", mgcp_ctx->rtp_endpoint); /* Generate MGCP message string */ 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->call_id, .conn_mode = MGCP_CONN_RECV_ONLY }; if (osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->rtp_endpoint, sizeof(mgcp_msg.endpoint)) >= MGCP_ENDPOINT_MAXLEN) { handle_error(mgcp_ctx, MGCP_ERR_TOOLONG, true); return; } msg = mgcp_msg_gen(mgcp, &mgcp_msg); OSMO_ASSERT(msg); /* Transmit MGCP message to MGW */ mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg); rc = mgcp_client_tx(mgcp, msg, mgw_crcx_cn_resp_cb, mgcp_ctx); if (rc < 0) { handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true); return; } osmo_fsm_inst_state_chg(fi, ST_CRCX_COMPL, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR); } /* Callback for MGCP-Client: handle response for CN associated CRCX */ static void mgw_crcx_cn_resp_cb(struct mgcp_response *r, void *priv) { struct mgcp_ctx *mgcp_ctx = priv; int rc; struct gsm_trans *trans; struct ran_conn *conn; OSMO_ASSERT(mgcp_ctx); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); if (r->head.response_code != 200) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/CN: response yields error: %d %s\n", r->head.response_code, r->head.comment); handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true); return; } /* memorize connection identifier */ osmo_strlcpy(mgcp_ctx->conn_id_cn, r->head.conn_id, sizeof(mgcp_ctx->conn_id_cn)); LOGPFSML(mgcp_ctx->fsm, LOGL_DEBUG, "CRCX/CN: MGW responded with CI: %s\n", mgcp_ctx->conn_id_cn); rc = mgcp_response_parse_params(r); if (rc) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/CN: Cannot parse response\n"); handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP, true); return; } LOGPFSML(mgcp_ctx->fsm, LOGL_DEBUG, "CRCX/CN: MGW responded with address %s:%u\n", r->audio_ip, r->audio_port); conn->rtp.local_port_cn = r->audio_port; osmo_strlcpy(conn->rtp.local_addr_cn, r->audio_ip, sizeof(conn->rtp.local_addr_cn)); /* Notify the FSM that we got the response. */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_CRCX_CN_RESP, mgcp_ctx); } /* Callback for ST_CRCX_COMPL: check MGW response, start assignment */ static void fsm_crcx_compl(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct gsm_trans *trans; struct ran_conn *conn; OSMO_ASSERT(mgcp_ctx); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); switch (event) { case EV_CRCX_CN_RESP: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } /* Forward assignment request to A/RANAP */ if (conn->via_ran == OSMO_RAT_UTRAN_IU) { #ifdef BUILD_IU /* Assign a voice channel via RANAP on 3G */ if (iu_rab_act_cs(trans)) goto error; #else LOGPFSML(fi, LOGL_ERROR, "Cannot send Iu RAB Assignment: built without Iu support\n"); goto error; #endif } else if (conn->via_ran == OSMO_RAT_GERAN_A) { /* Assign a voice channel via A on 2G */ if (a_iface_tx_assignment(trans)) goto error; } else { /* Unset or unimplemented new RAN type */ LOGPFSML(fi, LOGL_ERROR, "Unknown RAN type: %d\n", conn->via_ran); return; } /* Respond back to MNCC (if requested) */ if (trans->tch_rtp_create) { if (gsm48_tch_rtp_create(trans)) goto error; } /* Note: When we reach this point then the situation is basically that * we have two sides connected, both are in loopback. The local ports * of the side pointing towards the BSS should be already communicated * and we are waiting now the other end to pick up. */ osmo_fsm_inst_state_chg(fi, ST_MDCX_CN, MGCP_RAN_TIMEOUT, MGCP_RAN_TIMEOUT_TIMER_NR); return; error: handle_error(mgcp_ctx, MGCP_ERR_ASSGMNT_FAIL, true); } static void mgw_mdcx_cn_resp_cb(struct mgcp_response *r, void *priv); /* Callback for ST_MDCX_CN: send MDCX for RAN side to MGW */ static void fsm_mdcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct mgcp_client *mgcp; struct gsm_trans *trans; struct ran_conn *conn; struct mgcp_msg mgcp_msg; struct msgb *msg; int rc; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); switch (event) { case EV_CONNECT: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } LOGPFSML(fi, LOGL_DEBUG, "MDCX/CN: completing connection for the CN side on MGW endpoint:%p, remote leg expects RTP input on address %s:%u\n", mgcp_ctx->rtp_endpoint, conn->rtp.remote_addr_cn, conn->rtp.remote_port_cn); /* Generate MGCP message string */ 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->call_id, .conn_id = mgcp_ctx->conn_id_cn, .conn_mode = MGCP_CONN_RECV_SEND, .audio_ip = conn->rtp.remote_addr_cn, .audio_port = conn->rtp.remote_port_cn, .codecs[0] = conn->rtp.codec_cn, .codecs_len = 1 }; if (osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->rtp_endpoint, sizeof(mgcp_msg.endpoint)) >= MGCP_ENDPOINT_MAXLEN) { handle_error(mgcp_ctx, MGCP_ERR_TOOLONG, true); return; } msg = mgcp_msg_gen(mgcp, &mgcp_msg); OSMO_ASSERT(msg); /* Transmit MGCP message to MGW */ mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg); rc = mgcp_client_tx(mgcp, msg, mgw_mdcx_cn_resp_cb, mgcp_ctx); if (rc < 0) { handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true); return; } osmo_fsm_inst_state_chg(fi, ST_MDCX_CN_COMPL, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR); } /* Callback for MGCP-Client: handle response for CN associated CRCX */ static void mgw_mdcx_cn_resp_cb(struct mgcp_response *r, void *priv) { struct mgcp_ctx *mgcp_ctx = priv; OSMO_ASSERT(mgcp_ctx); if (r->head.response_code != 200) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "MDCX/CN: response yields error: %d %s\n", r->head.response_code, r->head.comment); handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true); return; } /* Notify the FSM that we got the response. */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_MDCX_CN_RESP, mgcp_ctx); } /* Callback for ST_MDCX_CN_COMPL: wait for mgw response, move on with the MDCX * for the RAN side if we already have valid IP/Port data for the RAN sided * RTP stream. */ static void fsm_mdcx_cn_compl_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct ran_conn *conn; struct gsm_trans *trans; OSMO_ASSERT(mgcp_ctx); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); switch (event) { case EV_MDCX_CN_RESP: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } /* Enter MDCX phase, but we must be sure that the Assigmnet on the A or * IuCS interface is complete (IP-Address and Port are valid) */ osmo_fsm_inst_state_chg(fi, ST_MDCX_RAN, MGCP_ASS_TIMEOUT, MGCP_ASS_TIMEOUT_TIMER_NR); /* If we already have a valid remote port and IP-Address from the RAN side * call leg, the assignment has been completed before we got here, so we * may move on immediately */ if (conn->rtp.remote_port_ran != 0 || strlen(conn->rtp.remote_addr_ran) > 0) osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_ASSIGN, mgcp_ctx); } static void mgw_mdcx_ran_resp_cb(struct mgcp_response *r, void *priv); /* Callback for ST_MDCX_RAN: wait for assignment completion, send MDCX for CN side to MGW */ static void fsm_mdcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct mgcp_client *mgcp; struct gsm_trans *trans; struct ran_conn *conn; struct mgcp_msg mgcp_msg; struct msgb *msg; int rc; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); trans = mgcp_ctx->trans; OSMO_ASSERT(trans); conn = trans->conn; OSMO_ASSERT(conn); switch (event) { case EV_ASSIGN: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } LOGPFSML(fi, LOGL_DEBUG, "MDCX/RAN: completing connection for the CN side on MGW endpoint:%p, RAN expects RTP input on address %s:%u\n", mgcp_ctx->rtp_endpoint, conn->rtp.remote_addr_ran, conn->rtp.remote_port_ran); /* Generate MGCP message string */ 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->call_id, .conn_id = mgcp_ctx->conn_id_ran, .conn_mode = MGCP_CONN_RECV_SEND, .audio_ip = conn->rtp.remote_addr_ran, .audio_port = conn->rtp.remote_port_ran, .codecs[0] = conn->rtp.codec_ran, .codecs_len = 1 }; if (osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->rtp_endpoint, sizeof(mgcp_msg.endpoint)) >= MGCP_ENDPOINT_MAXLEN) { handle_error(mgcp_ctx, MGCP_ERR_TOOLONG, true); return; } msg = mgcp_msg_gen(mgcp, &mgcp_msg); OSMO_ASSERT(msg); /* Transmit MGCP message to MGW */ mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg); rc = mgcp_client_tx(mgcp, msg, mgw_mdcx_ran_resp_cb, mgcp_ctx); if (rc < 0) { handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true); return; } osmo_fsm_inst_state_chg(fi, ST_MDCX_RAN_COMPL, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR); } /* Callback for MGCP-Client: handle response for CN associated CRCX */ static void mgw_mdcx_ran_resp_cb(struct mgcp_response *r, void *priv) { struct mgcp_ctx *mgcp_ctx = priv; OSMO_ASSERT(mgcp_ctx); if (r->head.response_code != 200) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "MDCX/RAN: response yields error: %d %s\n", r->head.response_code, r->head.comment); handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true); return; } /* Notify the FSM that we got the response. */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_MDCX_RAN_RESP, mgcp_ctx); } /* Callback for ST_MDCX_RAN_COMPL: check MGW response */ static void fsm_mdcx_ran_compl_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_RAN_RESP: break; default: handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true); return; } LOGPFSML(fi, LOGL_DEBUG, "call active, waiting for teardown...\n"); osmo_fsm_inst_state_chg(fi, ST_CALL, 0, 0); } static void mgw_dlcx_all_resp_cb(struct mgcp_response *r, void *priv); /* Callback for ST_CALL: call is active, send DLCX for both sides on teardown */ static void fsm_call_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = (struct mgcp_ctx *)data; struct mgcp_client *mgcp; struct mgcp_msg mgcp_msg; struct msgb *msg; int rc; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); LOGPFSML(fi, LOGL_DEBUG, "DLCX: removing connection for the RAN and CN side on MGW endpoint:%s...\n", mgcp_ctx->rtp_endpoint); /* Generate MGCP message string */ mgcp_msg = (struct mgcp_msg) { .verb = MGCP_VERB_DLCX, .presence = (MGCP_MSG_PRESENCE_ENDPOINT | MGCP_MSG_PRESENCE_CALL_ID), .call_id = mgcp_ctx->call_id }; if (osmo_strlcpy(mgcp_msg.endpoint, mgcp_ctx->rtp_endpoint, sizeof(mgcp_msg.endpoint)) >= MGCP_ENDPOINT_MAXLEN) { handle_error(mgcp_ctx, MGCP_ERR_TOOLONG, true); return; } msg = mgcp_msg_gen(mgcp, &mgcp_msg); OSMO_ASSERT(msg); /* Transmit MGCP message to MGW */ mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg); rc = mgcp_client_tx(mgcp, msg, mgw_dlcx_all_resp_cb, mgcp_ctx); if (rc < 0) { handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true); return; } osmo_fsm_inst_state_chg(fi, ST_HALT, MGCP_MGW_TIMEOUT, MGCP_MGW_TIMEOUT_TIMER_NR); } /* Callback for MGCP-Client: handle response for CN associated CRCX */ static void mgw_dlcx_all_resp_cb(struct mgcp_response *r, void *priv) { struct mgcp_ctx *mgcp_ctx = priv; OSMO_ASSERT(mgcp_ctx); /* DLCX is the only command where 250 is permitted as positive result */ if (r->head.response_code != 200 && r->head.response_code != 250) { LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "DLCX: response yields error: %d %s\n", r->head.response_code, r->head.comment); handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true); return; } /* Notify the FSM that we got the response. */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_DLCX_ALL_RESP, mgcp_ctx); } /* Callback for ST_HALT: Terminate the state machine */ static void fsm_halt_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct mgcp_ctx *mgcp_ctx = data; struct mgcp_client *mgcp; OSMO_ASSERT(mgcp_ctx); mgcp = mgcp_ctx->mgcp; OSMO_ASSERT(mgcp); /* NOTE: We must not free the context information now, we have to * wait until msc_mgcp_call_release() is called. Then we are sure * that the logic controlling us is fully aware that the context * information is freed. If we would free early now the controlling * logic might mistakenly think that the context info is still alive, * so lets keep the context info until we are explicitly asked for * throwing it away. */ if (mgcp_ctx->free_ctx) { /* Be sure that there is no pending MGW transaction */ mgcp_client_cancel(mgcp, mgcp_ctx->mgw_pending_trans); /* Free FSM and its context information */ osmo_fsm_inst_free(mgcp_ctx->fsm); talloc_free(mgcp_ctx); return; } osmo_fsm_inst_state_chg(fi, ST_HALT, MGCP_REL_TIMEOUT, MGCP_REL_TIMEOUT_TIMER_NR); } static struct osmo_fsm_state fsm_msc_mgcp_states[] = { /* Startup state machine, send CRCX for RAN side. */ [ST_CRCX_RAN] = { .in_event_mask = S(EV_INIT), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_CRCX_CN), .name = OSMO_STRINGIFY(ST_CRCX_RAN), .action = fsm_crcx_ran_cb, }, /* When the response to the RAN CRCX is received, then proceed with sending the CRCX for CN side */ [ST_CRCX_CN] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_CRCX_RAN_RESP), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_CRCX_COMPL), .name = OSMO_STRINGIFY(ST_CRCX_CN), .action = fsm_crcx_cn_cb, }, /* Complete the CRCX phase by starting the assignment. Depending on the * RAT (Radio Access Technology), this will either trigger an * Assignment Request on the A-Interface or an RAB-Assignment on the * IU-interface */ [ST_CRCX_COMPL] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_CRCX_CN_RESP), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_MDCX_CN), .name = OSMO_STRINGIFY(ST_CRCX_COMPL), .action = fsm_crcx_compl, }, /* Wait for MSC to complete the assignment request, when complete, we * will enter the MDCX phase by sending an MDCX for the CN side to the * MGW */ [ST_MDCX_CN] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_CONNECT), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_MDCX_CN_COMPL), .name = OSMO_STRINGIFY(ST_MDCX_CN), .action = fsm_mdcx_cn_cb, }, /* We arrive in this state when the MDCX phase for the CN side has * completed we will check the IP/Port of the RAN connection. If this * data is valid we may continue with the MDCX phase for the RAN side. * If not we wait until the assinment completes on the A or on the IuCS * interface. The completion of the assignment will fill in the port and * IP-Address of the RAN side and way may continue then. */ [ST_MDCX_CN_COMPL] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_MDCX_CN_RESP), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_MDCX_RAN), .name = OSMO_STRINGIFY(ST_MDCX_CN_COMPL), .action = fsm_mdcx_cn_compl_cb, }, /* When the response for the CN MDCX is received, send the MDCX for the * RAN side to the MGW */ [ST_MDCX_RAN] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_ASSIGN), .out_state_mask = S(ST_HALT) | S(ST_CALL) | S(ST_MDCX_RAN_COMPL), .name = OSMO_STRINGIFY(ST_MDCX_RAN), .action = fsm_mdcx_ran_cb, }, /* The RAN side MDCX phase is complete when the response is received * from the MGW. The call is then active, we change to ST_CALL and wait * there until the call ends. */ [ST_MDCX_RAN_COMPL] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_MDCX_RAN_RESP), .out_state_mask = S(ST_HALT) | S(ST_CALL), .name = OSMO_STRINGIFY(ST_MDCX_RAN_COMPL), .action = fsm_mdcx_ran_compl_cb, }, /* We are now in the active call phase, wait until the call is done * and send a DLCX then to remove all connections from the MGW */ [ST_CALL] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR), .out_state_mask = S(ST_HALT), .name = OSMO_STRINGIFY(ST_CALL), .action = fsm_call_cb, }, /* When the MGW confirms that the connections are terminated, then halt * the state machine. */ [ST_HALT] = { .in_event_mask = S(EV_TEARDOWN) | S(EV_TEARDOWN_ERROR) | S(EV_DLCX_ALL_RESP), .out_state_mask = S(ST_HALT), .name = OSMO_STRINGIFY(ST_HALT), .action = fsm_halt_cb, }, }; /* State machine definition */ static struct osmo_fsm fsm_msc_mgcp = { .name = "msc-mgcp", .states = fsm_msc_mgcp_states, .num_states = ARRAY_SIZE(fsm_msc_mgcp_states), .log_subsys = DMGCP, .timer_cb = fsm_timeout_cb, .event_names = msc_mgcp_fsm_evt_names, }; /* Try to invoke call assignment and set trans->cc.assignment_started flag if invoked. * This is relevant for already ongoing calls -- scenario: * - subscriber is in an active voice call, * - another call is coming in. * For the second call coming in, we must wait to establish RTP and assignment until the first call is CC-Disconnected. */ int msc_mgcp_try_call_assignment(struct gsm_trans *trans) { struct ran_conn *conn = trans->conn; if (trans->cc.assignment_started) return 0; if (conn->rtp.mgcp_ctx) { LOGPFSMSL(conn->fi, DMGCP, LOGL_INFO, "Another call is already ongoing, not assigning yet\n"); return 0; } LOGPFSMSL(conn->fi, DMGCP, LOGL_INFO, "Starting call assignment\n"); trans->cc.assignment_started = true; return msc_mgcp_call_assignment(trans); } /* Notify that a new call begins. This will create a connection for the * RAN and the CN on the MGW. * Parameter: * trans: transaction context. * Returns -EINVAL on error, 0 on success. */ int msc_mgcp_call_assignment(struct gsm_trans *trans) { struct mgcp_ctx *mgcp_ctx; static bool fsm_registered = false; struct ran_conn *conn; struct mgcp_client *mgcp; OSMO_ASSERT(trans); if (!trans->conn) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid conn, call assignment failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } conn = trans->conn; mgcp = conn->network->mgw.client; OSMO_ASSERT(mgcp); if (conn->rtp.mgcp_ctx) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) double assignment detected, dropping...\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } #ifdef BUILD_IU /* FIXME: HACK. where to scope the RAB Id? At the conn / subscriber / ranap_ue_conn_ctx? */ static uint8_t next_iu_rab_id = 1; if (conn->via_ran == OSMO_RAT_UTRAN_IU) conn->iu.rab_id = next_iu_rab_id++; #endif /* Register the fsm description (if not already done) */ if (fsm_registered == false) { osmo_fsm_register(&fsm_msc_mgcp); fsm_registered = true; } /* Allocate and configure a new fsm instance */ mgcp_ctx = talloc_zero(NULL, struct mgcp_ctx); OSMO_ASSERT(mgcp_ctx); if (osmo_strlcpy(mgcp_ctx->rtp_endpoint, mgcp_client_rtpbridge_wildcard(mgcp), sizeof(mgcp_ctx->rtp_endpoint)) >= sizeof(mgcp_ctx->rtp_endpoint)) { talloc_free(mgcp_ctx); LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) endpoint identifier exceeds maximum length: %s\n", vlr_subscr_name(trans->vsub), osmo_quote_str(mgcp_client_rtpbridge_wildcard(mgcp), -1)); return -EINVAL; } mgcp_ctx->fsm = osmo_fsm_inst_alloc(&fsm_msc_mgcp, NULL, NULL, LOGL_DEBUG, NULL); OSMO_ASSERT(mgcp_ctx->fsm); osmo_fsm_inst_update_id_f(mgcp_ctx->fsm, "%s_%s_trans%d", vlr_subscr_name(trans->vsub), ran_conn_get_conn_id(conn), trans->transaction_id); mgcp_ctx->fsm->priv = mgcp_ctx; mgcp_ctx->mgcp = mgcp; mgcp_ctx->trans = trans; mgcp_ctx->call_id = trans->callref; /* start state machine */ OSMO_ASSERT(mgcp_ctx->fsm->state == ST_CRCX_RAN); osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_INIT, mgcp_ctx); conn->rtp.mgcp_ctx = mgcp_ctx; LOGP(DMGCP, LOGL_DEBUG, "(subscriber:%s) call assignment initiated\n", vlr_subscr_name(conn->vsub)); return 0; } /* Inform the FSM that the assignment (RAN connection) is now complete. * Parameter: * conn: RAN connection context. * port: port number of the remote leg. * addr: IP-address of the remote leg. * Returns -EINVAL on error, 0 on success. */ int msc_mgcp_ass_complete(struct ran_conn *conn, uint16_t port, char *addr) { struct mgcp_ctx *mgcp_ctx; OSMO_ASSERT(conn); if (port == 0) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid remote call leg port, assignment completion failed\n", vlr_subscr_name(conn->vsub)); return -EINVAL; } if (!addr || strlen(addr) <= 0) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) missing remote call leg address, assignment completion failed\n", vlr_subscr_name(conn->vsub)); return -EINVAL; } mgcp_ctx = conn->rtp.mgcp_ctx; if (!mgcp_ctx) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid mgcp context, assignment completion failed.\n", vlr_subscr_name(conn->vsub)); return -EINVAL; } /* Memorize port and IP-Address of the remote RAN call leg. We need this * information at latest when we enter the MDCX phase for the RAN side. */ conn->rtp.remote_port_ran = port; osmo_strlcpy(conn->rtp.remote_addr_ran, addr, sizeof(conn->rtp.remote_addr_ran)); LOGP(DMGCP, LOGL_DEBUG, "(subscriber:%s) assignment completed, rtp %s:%d.\n", vlr_subscr_name(conn->vsub), conn->rtp.remote_addr_ran, port); /* Note: We only dispatch the event if we are really waiting for the * assignment, if we are not yet waiting, there is no need to loudly * broadcast an event that the all other states do not understand anyway */ if (mgcp_ctx->fsm->state == ST_MDCX_RAN) osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_ASSIGN, mgcp_ctx); return 0; } /* Notify the MGCP context that Assignment failed. * This will end the "ringing" on the other call leg, and will usually result in L3 and conn release (i.e. when no other * transactions are still pending, which is usually the case). */ int msc_mgcp_ass_fail(struct ran_conn *conn) { struct mgcp_ctx *mgcp_ctx; OSMO_ASSERT(conn); mgcp_ctx = conn->rtp.mgcp_ctx; if (!mgcp_ctx) return -EINVAL; LOGPFSMSL(conn->fi, DMGCP, LOGL_ERROR, "Assignment failed\n"); osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_TEARDOWN_ERROR, mgcp_ctx); return 0; } /* Make the connection of a previously assigned call complete * Parameter: * trans: transaction context. * port: port number of the remote leg. * addr: IP-address of the remote leg. * Returns -EINVAL on error, 0 on success. */ int msc_mgcp_call_complete(struct gsm_trans *trans, uint16_t port, char *addr) { struct mgcp_ctx *mgcp_ctx; struct ran_conn *conn; OSMO_ASSERT(trans); OSMO_ASSERT(addr); if (port == 0) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid remote call leg port, call completion failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (!addr || strlen(addr) <= 0) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) missing remote call leg address, call completion failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (!trans->conn) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid conn, call completion failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (!trans->conn->rtp.mgcp_ctx) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid mgcp context, call completion failed.\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (!trans->conn->rtp.mgcp_ctx->fsm) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) no FSM, call completion failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } mgcp_ctx = trans->conn->rtp.mgcp_ctx; /* The FSM should already have passed all CRCX phases and be ready to move * on with the MDCX phases. */ if (mgcp_ctx->fsm->state != ST_MDCX_CN) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid call state, call completion failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } conn = trans->conn; osmo_strlcpy(conn->rtp.remote_addr_cn, addr, sizeof(conn->rtp.remote_addr_cn)); conn->rtp.remote_port_cn = port; osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_CONNECT, mgcp_ctx); LOGP(DMGCP, LOGL_DEBUG, "(subscriber:%s) call completion initiated\n", vlr_subscr_name(conn->vsub)); return 0; } static struct gsm_trans *find_waiting_call(struct ran_conn *conn) { struct gsm_trans *trans; struct gsm_network *net = conn->network; llist_for_each_entry(trans, &net->trans_list, entry) { if (trans->conn != conn) continue; if (trans->protocol != GSM48_PDISC_CC) continue; if (trans->cc.assignment_started) continue; return trans; } return NULL; } /* Release ongoing call. * Parameter: * trans: connection context. * Returns -EINVAL on error, 0 on success. */ int msc_mgcp_call_release(struct gsm_trans *trans) { struct mgcp_ctx *mgcp_ctx; struct ran_conn *conn = trans->conn; struct gsm_trans *waiting_trans; OSMO_ASSERT(trans); if (!conn) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid conn, call release failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } mgcp_ctx = conn->rtp.mgcp_ctx; if (!mgcp_ctx) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) invalid mgcp context, call release failed.\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (!mgcp_ctx->fsm) { LOGP(DMGCP, LOGL_ERROR, "(subscriber:%s) no FSM, call release failed\n", vlr_subscr_name(trans->vsub)); return -EINVAL; } if (mgcp_ctx->trans != trans) { LOGP(DMGCP, LOGL_DEBUG, "(ti %02x %s) call release for background CC transaction\n", trans->transaction_id, vlr_subscr_name(trans->vsub)); return 0; } LOGP(DMGCP, LOGL_DEBUG, "(ti %02x %s) Call release: tearing down MGW endpoint\n", trans->transaction_id, vlr_subscr_name(trans->vsub)); /* Inform the FSM that as soon as it reaches ST_HALT it may free * all context information immediately */ mgcp_ctx->free_ctx = true; /* Initaite teardown, regardless of which state we are currently * in */ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_TEARDOWN, mgcp_ctx); /* Prevent any further operation that is triggered from outside by * overwriting the context pointer with NULL. The FSM will now * take care for a graceful shutdown and when done it will free * all related context information */ conn->rtp.mgcp_ctx = NULL; /* If there is another call still waiting to be activated, this is the time when the mgcp_ctx is available again * and the other call can start assigning. */ waiting_trans = find_waiting_call(conn); if (waiting_trans) { LOGP(DMGCP, LOGL_DEBUG, "(ti %02x %s) Call waiting: starting Assignment\n", waiting_trans->transaction_id, vlr_subscr_name(trans->vsub)); msc_mgcp_try_call_assignment(waiting_trans); } return 0; }