170 lines
6.1 KiB
C
170 lines
6.1 KiB
C
/* gprs_bssgp_pcu.cpp
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*
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* Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <osmocom/gprs/gprs_bssgp.h>
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#include <osmocom/gprs/gprs_bssgp_rim.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/gsm/tlv.h>
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#include <osmocom/gprs/gprs_ns.h>
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#include <osmocom/core/prim.h>
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#include "gprs_debug.h"
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#include "gprs_pcu.h"
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#define LOGPRIM(nsei, level, fmt, args...) \
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LOGP(DRIM, level, "(NSEI=%u) " fmt, nsei, ## args)
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static inline void gprs_ra_id_ci_to_cgi_ps(struct osmo_cell_global_id_ps *cgi_ps,
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const struct gprs_ra_id *raid, uint16_t cid)
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{
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*cgi_ps = (struct osmo_cell_global_id_ps) {
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.rai.lac.plmn.mcc = raid->mcc,
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.rai.lac.plmn.mnc = raid->mnc,
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.rai.lac.plmn.mnc_3_digits = raid->mnc_3_digits,
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.rai.lac.lac = raid->lac,
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.rai.rac = raid->rac,
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.cell_identity = cid,
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};
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}
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/* Mirror RIM routing information of a given PDU, see also 3GPP TS 48.018, section 8c.1.4.3 */
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static void mirror_rim_routing_info(struct bssgp_ran_information_pdu *to_pdu,
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const struct bssgp_ran_information_pdu *from_pdu)
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{
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memcpy(&to_pdu->routing_info_dest, &from_pdu->routing_info_src, sizeof(to_pdu->routing_info_dest));
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memcpy(&to_pdu->routing_info_src, &from_pdu->routing_info_dest, sizeof(to_pdu->routing_info_src));
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}
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/* Format a RAN INFORMATION ERROR PDU */
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static void format_response_pdu_err(struct bssgp_ran_information_pdu *resp_pdu,
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const struct bssgp_ran_information_pdu *req_pdu)
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{
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memset(resp_pdu, 0, sizeof(*resp_pdu));
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mirror_rim_routing_info(resp_pdu, req_pdu);
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resp_pdu->decoded.err_rim_cont = (struct bssgp_ran_inf_err_rim_cont) {
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.app_id = BSSGP_RAN_INF_APP_ID_NACC,
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.prot_ver = 1,
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.err_pdu = req_pdu->rim_cont,
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.err_pdu_len = req_pdu->rim_cont_len,
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};
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resp_pdu->decoded_present = true;
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resp_pdu->rim_cont_iei = BSSGP_IE_RI_ERROR_RIM_COINTAINER;
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}
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/* Check if the application ID in the request PDU is actually BSSGP_RAN_INF_APP_ID_NACC */
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static const enum bssgp_ran_inf_app_id *get_app_id(const struct bssgp_ran_information_pdu *pdu)
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{
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switch (pdu->rim_cont_iei) {
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case BSSGP_IE_RI_REQ_RIM_CONTAINER:
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return &pdu->decoded.req_rim_cont.app_id;
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case BSSGP_IE_RI_RIM_CONTAINER:
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return &pdu->decoded.rim_cont.app_id;
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case BSSGP_IE_RI_APP_ERROR_RIM_CONT:
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return &pdu->decoded.app_err_rim_cont.app_id;
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case BSSGP_IE_RI_ACK_RIM_CONTAINER:
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return &pdu->decoded.ack_rim_cont.app_id;
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case BSSGP_IE_RI_ERROR_RIM_COINTAINER:
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return &pdu->decoded.err_rim_cont.app_id;
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default:
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return NULL;
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}
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}
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/* Check if the application ID in the request PDU is of a certain type */
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static bool match_app_id(const struct bssgp_ran_information_pdu *pdu, enum bssgp_ran_inf_app_id exp_app_id)
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{
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const enum bssgp_ran_inf_app_id *app_id = get_app_id(pdu);
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if (app_id && *app_id == exp_app_id)
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return true;
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return false;
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}
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int handle_rim(struct osmo_bssgp_prim *bp)
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{
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struct msgb *msg = bp->oph.msg;
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uint16_t nsei = msgb_nsei(msg);
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struct bssgp_ran_information_pdu *pdu = &bp->u.rim_pdu;
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struct bssgp_ran_information_pdu resp_pdu;
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struct osmo_cell_global_id_ps dst_addr;
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struct gprs_rlcmac_bts *bts;
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OSMO_ASSERT (bp->oph.sap == SAP_BSSGP_RIM);
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/* At the moment we only support GERAN, so we block all other network
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* types here. */
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if (pdu->routing_info_dest.discr != BSSGP_RIM_ROUTING_INFO_GERAN) {
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LOGPRIM(nsei, LOGL_ERROR,
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"Only GERAN supported, destination cell is not a GERAN cell -- rejected.\n");
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return bssgp_tx_status(BSSGP_CAUSE_UNKN_RIM_AI, NULL, msg);
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}
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/* Check if the RIM pdu is really addressed to this PCU. In case we
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* receive a RIM PDU for a cell that is not parented by this PCU we
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* are supposed to reject it with a BSSGP STATUS.
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* see also: 3GPP TS 48.018, section 8c.3.1.2 */
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gprs_ra_id_ci_to_cgi_ps(&dst_addr, &pdu->routing_info_dest.geran.raid,
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pdu->routing_info_dest.geran.cid);
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bts = gprs_pcu_get_bts_by_cgi_ps(the_pcu, &dst_addr);
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if (!bts) {
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LOGPRIM(nsei, LOGL_ERROR, "Cell %s unknown to this pcu\n",
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osmo_cgi_ps_name(&dst_addr));
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return bssgp_tx_status(BSSGP_CAUSE_UNKN_DST, NULL, msg);
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}
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/* Check if the incoming RIM PDU is parseable, if not we must report
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* an error to the controlling BSS 3GPP TS 48.018, 8c.3.4 and 8c.3.4.2 */
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if (!pdu->decoded_present) {
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LOGPRIM(nsei, LOGL_ERROR, "Errornous RIM PDU received -- rejected.\n");
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format_response_pdu_err(&resp_pdu, pdu);
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return 0;
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}
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/* Check if the RIM container inside the incoming RIM PDU has the correct
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* application ID */
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if (!match_app_id(pdu, BSSGP_RAN_INF_APP_ID_NACC)) {
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LOGPRIM(nsei, LOGL_ERROR, "RIM PDU with unknown/wrong application ID received -- rejected.\n");
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format_response_pdu_err(&resp_pdu, pdu);
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return 0;
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}
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/* Handle incoming RIM container */
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switch (pdu->rim_cont_iei) {
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case BSSGP_IE_RI_REQ_RIM_CONTAINER:
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LOGPRIM(nsei, LOGL_NOTICE, "Responding to RAN INFORMATION REQUEST not yet implemented!\n");
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break;
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case BSSGP_IE_RI_RIM_CONTAINER:
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LOGPRIM(nsei, LOGL_NOTICE, "Responding to RAN INFORMATION not yet implemented!\n");
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break;
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case BSSGP_IE_RI_APP_ERROR_RIM_CONT:
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case BSSGP_IE_RI_ACK_RIM_CONTAINER:
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case BSSGP_IE_RI_ERROR_RIM_COINTAINER:
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LOGPRIM(nsei, LOGL_ERROR, "RIM PDU not handled by this application\n");
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return -EINVAL;
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default:
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/* This should never happen. If the RIM PDU is parsed correctly, then the rim_cont_iei will
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* be set to one of the cases above and if parsing fails this switch statement is guarded
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* by the check on decoded_present above */
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OSMO_ASSERT(false);
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}
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return 0;
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}
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