/* gprs_bssgp_pcu.cpp * * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH * * 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 #include #include #include #include #include #include #include #include #include "gprs_debug.h" #include "gprs_pcu.h" #include "bts.h" #include "gprs_ms.h" #include "nacc_fsm.h" #define LOGPRIM(nsei, level, fmt, args...) \ LOGP(DRIM, level, "(NSEI=%u) " fmt, nsei, ## args) static inline void gprs_ra_id_ci_to_cgi_ps(struct osmo_cell_global_id_ps *cgi_ps, const struct gprs_ra_id *raid, uint16_t cid) { *cgi_ps = (struct osmo_cell_global_id_ps) { .rai.lac.plmn.mcc = raid->mcc, .rai.lac.plmn.mnc = raid->mnc, .rai.lac.plmn.mnc_3_digits = raid->mnc_3_digits, .rai.lac.lac = raid->lac, .rai.rac = raid->rac, .cell_identity = cid, }; } /* Mirror RIM routing information of a given PDU, see also 3GPP TS 48.018, section 8c.1.4.3 */ static void mirror_rim_routing_info(struct bssgp_ran_information_pdu *to_pdu, const struct bssgp_ran_information_pdu *from_pdu) { memcpy(&to_pdu->routing_info_dest, &from_pdu->routing_info_src, sizeof(to_pdu->routing_info_dest)); memcpy(&to_pdu->routing_info_src, &from_pdu->routing_info_dest, sizeof(to_pdu->routing_info_src)); } /* Fill NACC application container with data (cell identifier, sysinfo) */ #define SI_HDR_LEN 2 static void fill_app_cont_nacc(struct bssgp_ran_inf_app_cont_nacc *app_cont, const struct gprs_rlcmac_bts *bts) { struct bssgp_bvc_ctx *bctx = the_pcu->bssgp.bctx; gprs_ra_id_ci_to_cgi_ps(&app_cont->reprt_cell, &bctx->ra_id, bctx->cell_id); app_cont->num_si = 0; /* Note: The BTS struct stores the system information including its pseudo header. The RIM application * container defines the system information without pseudo header, so we need to chop it off. */ if (bts->si1_is_set) { app_cont->si[app_cont->num_si] = bts->si1 + SI_HDR_LEN; app_cont->num_si++; } if (bts->si3_is_set) { app_cont->si[app_cont->num_si] = bts->si3 + SI_HDR_LEN; app_cont->num_si++; } if (bts->si13_is_set) { app_cont->si[app_cont->num_si] = bts->si13 + SI_HDR_LEN; app_cont->num_si++; } /* Note: It is possible that the resulting PDU will not contain any system information, even if this is * an unlikely case since the BTS immediately updates the system information after startup. The * specification permits to send zero system information, see also: 3GPP TS 48.018 section 11.3.63.2.1 */ if (!bts->si1_is_set || !bts->si3_is_set || !bts->si13_is_set) LOGP(DNACC, LOGL_INFO, "TX RAN INFO RESPONSE (NACC) %s: Some SI are missing:%s%s%s\n", osmo_cgi_ps_name(&app_cont->reprt_cell), bts->si1_is_set ? "" : " SI1", bts->si3_is_set ? "" : " SI3", bts->si13_is_set ? "" : " SI13"); } /* Format a RAN INFORMATION PDU that contains the requested system information */ static void format_response_pdu(struct bssgp_ran_information_pdu *resp_pdu, const struct bssgp_ran_information_pdu *req_pdu, const struct gprs_rlcmac_bts *bts) { memset(resp_pdu, 0, sizeof(*resp_pdu)); mirror_rim_routing_info(resp_pdu, req_pdu); resp_pdu->decoded.rim_cont = (struct bssgp_ran_inf_rim_cont) { .app_id = BSSGP_RAN_INF_APP_ID_NACC, .seq_num = 1, /* single report has only one message in response */ .pdu_ind = { .pdu_type_ext = RIM_PDU_TYPE_SING_REP, }, .prot_ver = 1, }; fill_app_cont_nacc(&resp_pdu->decoded.rim_cont.u.app_cont_nacc, bts); resp_pdu->decoded_present = true; resp_pdu->rim_cont_iei = BSSGP_IE_RI_RIM_CONTAINER; } /* Format a RAN INFORMATION ERROR PDU */ static void format_response_pdu_err(struct bssgp_ran_information_pdu *resp_pdu, const struct bssgp_ran_information_pdu *req_pdu) { memset(resp_pdu, 0, sizeof(*resp_pdu)); mirror_rim_routing_info(resp_pdu, req_pdu); resp_pdu->decoded.err_rim_cont = (struct bssgp_ran_inf_err_rim_cont) { .app_id = BSSGP_RAN_INF_APP_ID_NACC, .prot_ver = 1, .err_pdu = req_pdu->rim_cont, .err_pdu_len = req_pdu->rim_cont_len, }; resp_pdu->decoded_present = true; resp_pdu->rim_cont_iei = BSSGP_IE_RI_ERROR_RIM_COINTAINER; } static int handle_ran_info_response_nacc(const struct bssgp_ran_inf_app_cont_nacc *nacc, struct gprs_rlcmac_bts *bts) { struct si_cache_value val; struct si_cache_entry *entry; struct llist_head *tmp; int i; LOGP(DRIM, LOGL_INFO, "Rx RAN-INFO cell=%s type=%sBCCH num_si=%d\n", osmo_cgi_ps_name(&nacc->reprt_cell), nacc->type_psi ? "P" : "", nacc->num_si); val.type_psi = nacc->type_psi; val.si_len = 0; for (i = 0; i < nacc->num_si; i++) { size_t len = val.type_psi ? BSSGP_RIM_PSI_LEN : BSSGP_RIM_SI_LEN; memcpy(&val.si_buf[val.si_len], nacc->si[i], len); val.si_len += len; } entry = si_cache_add(bts->pcu->si_cache, &nacc->reprt_cell, &val); llist_for_each(tmp, &bts->ms_list) { struct GprsMs *ms = llist_entry(tmp, typeof(*ms), list); if (ms->nacc && nacc_fsm_is_waiting_si_resolution(ms->nacc, &nacc->reprt_cell)) osmo_fsm_inst_dispatch(ms->nacc->fi, NACC_EV_RX_SI, entry); } return 0; } static int handle_ran_info_request(const struct bssgp_ran_information_pdu *pdu, struct gprs_rlcmac_bts *bts, uint16_t nsei) { const struct bssgp_ran_inf_req_rim_cont *ri_req = &pdu->decoded.req_rim_cont; const struct bssgp_ran_inf_req_app_cont_nacc *nacc_req; struct bssgp_ran_information_pdu resp_pdu; int rc; /* Check if we support the application ID */ if (ri_req->app_id != BSSGP_RAN_INF_APP_ID_NACC) { LOGPRIM(nsei, LOGL_ERROR, "Rx RAN-INFO-REQ for cell %s with unknown/wrong application ID %s -- reject.\n", osmo_cgi_ps_name(&bts->cgi_ps), bssgp_ran_inf_app_id_str(ri_req->app_id)); format_response_pdu_err(&resp_pdu, pdu); rc = -ENOTSUP; goto tx_ret; } nacc_req = &ri_req->u.app_cont_nacc; rc = osmo_cgi_ps_cmp(&bts->cgi_ps, &nacc_req->reprt_cell); if (rc != 0) { LOGPRIM(nsei, LOGL_ERROR, "reporting cell in RIM application container %s " "does not match destination cell in RIM routing info %s -- rejected.\n", osmo_cgi_ps_name(&nacc_req->reprt_cell), osmo_cgi_ps_name2(&bts->cgi_ps)); format_response_pdu_err(&resp_pdu, pdu); } else { LOGPRIM(nsei, LOGL_INFO, "Responding to RAN INFORMATION REQUEST %s ...\n", osmo_cgi_ps_name(&nacc_req->reprt_cell)); format_response_pdu(&resp_pdu, pdu, bts); } tx_ret: bssgp_tx_rim(&resp_pdu, nsei); return rc; } static int handle_ran_info_response(const struct bssgp_ran_information_pdu *pdu, struct gprs_rlcmac_bts *bts) { const struct bssgp_ran_inf_rim_cont *ran_info = &pdu->decoded.rim_cont; char ri_src_str[64]; /* Check if we support the application ID */ if (ran_info->app_id != BSSGP_RAN_INF_APP_ID_NACC) { LOGP(DRIM, LOGL_ERROR, "Rx RAN-INFO for cell %s with unknown/wrong application ID %s received -- reject.\n", osmo_cgi_ps_name(&bts->cgi_ps), bssgp_ran_inf_app_id_str(ran_info->app_id)); return -1; } if (ran_info->app_err) { LOGP(DRIM, LOGL_ERROR, "%s Rx RAN-INFO with an app error! cause: %s\n", bssgp_rim_ri_name_buf(ri_src_str, sizeof(ri_src_str), &pdu->routing_info_src), bssgp_nacc_cause_str(ran_info->u.app_err_cont_nacc.nacc_cause)); return -1; } handle_ran_info_response_nacc(&ran_info->u.app_cont_nacc, bts); return 0; } int handle_rim(struct osmo_bssgp_prim *bp) { struct msgb *msg = bp->oph.msg; uint16_t nsei = msgb_nsei(msg); struct bssgp_ran_information_pdu *pdu = &bp->u.rim_pdu; struct bssgp_ran_information_pdu resp_pdu; struct osmo_cell_global_id_ps dst_addr; struct gprs_rlcmac_bts *bts; OSMO_ASSERT (bp->oph.sap == SAP_BSSGP_RIM); /* At the moment we only support GERAN, so we block all other network * types here. */ if (pdu->routing_info_dest.discr != BSSGP_RIM_ROUTING_INFO_GERAN) { LOGPRIM(nsei, LOGL_ERROR, "Only GERAN supported, destination cell is not a GERAN cell -- rejected.\n"); return bssgp_tx_status(BSSGP_CAUSE_UNKN_RIM_AI, NULL, msg); } /* Check if the RIM pdu is really addressed to this PCU. In case we * receive a RIM PDU for a cell that is not parented by this PCU we * are supposed to reject it with a BSSGP STATUS. * see also: 3GPP TS 48.018, section 8c.3.1.2 */ gprs_ra_id_ci_to_cgi_ps(&dst_addr, &pdu->routing_info_dest.geran.raid, pdu->routing_info_dest.geran.cid); bts = gprs_pcu_get_bts_by_cgi_ps(the_pcu, &dst_addr); if (!bts) { LOGPRIM(nsei, LOGL_ERROR, "Destination cell %s unknown to this pcu\n", osmo_cgi_ps_name(&dst_addr)); return bssgp_tx_status(BSSGP_CAUSE_UNKN_DST, NULL, msg); } /* Check if the incoming RIM PDU is parseable, if not we must report * an error to the controlling BSS 3GPP TS 48.018, 8c.3.4 and 8c.3.4.2 */ if (!pdu->decoded_present) { LOGPRIM(nsei, LOGL_ERROR, "Erroneous RIM PDU received for cell %s -- reject.\n", osmo_cgi_ps_name(&dst_addr)); format_response_pdu_err(&resp_pdu, pdu); return 0; } /* Handle incoming RIM container */ switch (pdu->rim_cont_iei) { case BSSGP_IE_RI_REQ_RIM_CONTAINER: return handle_ran_info_request(pdu, bts, nsei); case BSSGP_IE_RI_RIM_CONTAINER: return handle_ran_info_response(pdu, bts); case BSSGP_IE_RI_APP_ERROR_RIM_CONT: case BSSGP_IE_RI_ACK_RIM_CONTAINER: case BSSGP_IE_RI_ERROR_RIM_COINTAINER: LOGPRIM(nsei, LOGL_ERROR, "RIM PDU not handled by this application\n"); return -EINVAL; default: /* This should never happen. If the RIM PDU is parsed correctly, then the rim_cont_iei will * be set to one of the cases above and if parsing fails this switch statement is guarded * by the check on decoded_present above */ OSMO_ASSERT(false); } return 0; }