105 lines
3.2 KiB
C
105 lines
3.2 KiB
C
/* MSC Handover API */
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/*
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* (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* SPDX-License-Identifier: AGPL-3.0+
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*
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* Author: Neels Hofmeyr
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/core/sockaddr_str.h>
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#include <osmocom/mgcp_client/mgcp_client.h>
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#include <osmocom/msc/neighbor_ident.h>
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#include <osmocom/msc/ran_msg.h>
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#include <osmocom/msc/mncc_call.h>
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#include <osmocom/msc/sdp_msg.h>
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struct gsm0808_handover_required;
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struct msc_a;
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struct ran_dec_handover_required;
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#define LOG_HO(msc_a, level, fmt, args...) \
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LOGPFSML((msc_a)? ((msc_a)->ho.fi ? : (msc_a)->c.fi) : NULL, \
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level, "%s" fmt, (msc_a->ho.fi ? "" : "HO: "), ##args)
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enum msc_ho_fsm_state {
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MSC_HO_ST_REQUIRED,
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MSC_HO_ST_WAIT_REQUEST_ACK,
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MSC_HO_ST_WAIT_COMPLETE,
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};
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enum msc_ho_fsm_event {
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MSC_HO_EV_RX_REQUEST_ACK,
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MSC_HO_EV_RX_DETECT,
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MSC_HO_EV_RX_COMPLETE,
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MSC_HO_EV_RX_FAILURE,
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MSC_HO_EV_MNCC_FORWARDING_COMPLETE,
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MSC_HO_EV_MNCC_FORWARDING_FAILED,
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};
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struct msc_ho_state {
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struct osmo_fsm_inst *fi;
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struct ran_handover_required info;
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unsigned int next_cil_idx;
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bool subsequent_ho;
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bool ready_to_switch_rtp;
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bool rtp_switched_to_new_cell;
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struct {
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enum osmo_rat_type ran_type;
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struct gsm0808_cell_id cid;
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struct osmo_cell_global_id cgi;
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enum msc_neighbor_type type;
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union {
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struct ran_peer *ran_peer;
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const char *msc_ipa_name;
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};
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/* The RTP address from Handover Request Acknowledge.
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* Might be from AoIP Transport Layer Address from a BSC RAN peer,
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* or from MNCC forwarding for inter-MSC handover. */
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struct osmo_sockaddr_str ran_remote_rtp;
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/* The codec from Handover Request Acknowledge. */
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bool codec_present;
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enum mgcp_codecs codec;
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/* Inter-MSC voice forwarding via MNCC, to the remote MSC. The Prepare Handover Response sent us the
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* Handover Number the remote MSC assigned. This is a call to that Handover Number, via PBX.
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* (NULL if not an inter-MSC Handover) */
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struct mncc_call *mncc_forwarding_to_remote_ran;
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} new_cell;
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struct {
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/* Saved RTP IP:port and codec in case we need to roll back */
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struct osmo_sockaddr_str ran_remote_rtp;
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struct sdp_audio_codecs codecs;
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} old_cell;
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};
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void msc_ho_start(struct msc_a *msc_a, const struct ran_handover_required *ho_req);
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enum msc_neighbor_type msc_ho_find_target_cell(struct msc_a *msc_a, const struct gsm0808_cell_id *cid,
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const struct neighbor_ident_entry **remote_msc,
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struct ran_peer **ran_peer_from_neighbor_ident,
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struct ran_peer **ran_peer_from_seen_cells);
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