From 218e4b4aa0fc6de842ff820dec8e97d1f083268a Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Tue, 4 Jul 2017 23:08:44 +0200 Subject: move openbsc/* to repos root This is the first step in creating this repository from the legacy openbsc.git. Like all other Osmocom repositories, keep the autoconf and automake files in the repository root. openbsc.git has been the sole exception, which ends now. Change-Id: I9c6f2a448d9cb1cc088cf1cf6918b69d7e69b4e7 --- src/osmo-bsc/osmo_bsc_filter.c | 381 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 381 insertions(+) create mode 100644 src/osmo-bsc/osmo_bsc_filter.c (limited to 'src/osmo-bsc/osmo_bsc_filter.c') diff --git a/src/osmo-bsc/osmo_bsc_filter.c b/src/osmo-bsc/osmo_bsc_filter.c new file mode 100644 index 000000000..2c84b169f --- /dev/null +++ b/src/osmo-bsc/osmo_bsc_filter.c @@ -0,0 +1,381 @@ +/* (C) 2009-2011 by Holger Hans Peter Freyther + * (C) 2009-2011 by On-Waves + * All Rights Reserved + * + * 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 + +static void handle_lu_request(struct gsm_subscriber_connection *conn, + struct msgb *msg) +{ + struct gsm48_hdr *gh; + struct gsm48_loc_upd_req *lu; + struct gsm48_loc_area_id lai; + struct gsm_network *net; + + if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*lu)) { + LOGP(DMSC, LOGL_ERROR, "LU too small to look at: %u\n", msgb_l3len(msg)); + return; + } + + net = conn->bts->network; + + gh = msgb_l3(msg); + lu = (struct gsm48_loc_upd_req *) gh->data; + + gsm48_generate_lai(&lai, net->country_code, net->network_code, + conn->bts->location_area_code); + + if (memcmp(&lai, &lu->lai, sizeof(lai)) != 0) { + LOGP(DMSC, LOGL_DEBUG, "Marking con for welcome USSD.\n"); + conn->sccp_con->new_subscriber = 1; + } +} + +/* extract a subscriber from the paging response */ +static struct bsc_subscr *extract_sub(struct gsm_subscriber_connection *conn, + struct msgb *msg) +{ + uint8_t mi_type; + char mi_string[GSM48_MI_SIZE]; + struct gsm48_hdr *gh; + struct gsm48_pag_resp *resp; + struct bsc_subscr *subscr; + + if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*resp)) { + LOGP(DMSC, LOGL_ERROR, "PagingResponse too small: %u\n", msgb_l3len(msg)); + return NULL; + } + + gh = msgb_l3(msg); + resp = (struct gsm48_pag_resp *) &gh->data[0]; + + gsm48_paging_extract_mi(resp, msgb_l3len(msg) - sizeof(*gh), + mi_string, &mi_type); + DEBUGP(DRR, "PAGING RESPONSE: MI(%s)=%s\n", + gsm48_mi_type_name(mi_type), mi_string); + + switch (mi_type) { + case GSM_MI_TYPE_TMSI: + subscr = bsc_subscr_find_by_tmsi(conn->network->bsc_subscribers, + tmsi_from_string(mi_string)); + break; + case GSM_MI_TYPE_IMSI: + subscr = bsc_subscr_find_by_imsi(conn->network->bsc_subscribers, + mi_string); + break; + default: + subscr = NULL; + break; + } + + return subscr; +} + +/* we will need to stop the paging request */ +static int handle_page_resp(struct gsm_subscriber_connection *conn, struct msgb *msg) +{ + struct bsc_subscr *subscr = extract_sub(conn, msg); + + if (!subscr) { + LOGP(DMSC, LOGL_ERROR, "Non active subscriber got paged.\n"); + return -1; + } + + paging_request_stop(&conn->network->bts_list, conn->bts, subscr, conn, + msg); + bsc_subscr_put(subscr); + return 0; +} + +static int is_cm_service_for_emerg(struct msgb *msg) +{ + struct gsm48_service_request *cm; + struct gsm48_hdr *gh = msgb_l3(msg); + + if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*cm)) { + LOGP(DMSC, LOGL_ERROR, "CM ServiceRequest does not fit.\n"); + return 0; + } + + cm = (struct gsm48_service_request *) &gh->data[0]; + return cm->cm_service_type == GSM48_CMSERV_EMERGENCY; +} + +struct bsc_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn, + struct msgb *msg) +{ + struct gsm48_hdr *gh; + int8_t pdisc; + uint8_t mtype; + struct osmo_bsc_data *bsc; + struct bsc_msc_data *msc, *pag_msc; + struct bsc_subscr *subscr; + int is_emerg = 0; + + bsc = conn->bts->network->bsc_data; + + if (msgb_l3len(msg) < sizeof(*gh)) { + LOGP(DMSC, LOGL_ERROR, "There is no GSM48 header here.\n"); + return NULL; + } + + gh = msgb_l3(msg); + pdisc = gsm48_hdr_pdisc(gh); + mtype = gsm48_hdr_msg_type(gh); + + /* + * We are asked to select a MSC here but they are not equal. We + * want to respond to a paging request on the MSC where we got the + * request from. This is where we need to decide where this connection + * will go. + */ + if (pdisc == GSM48_PDISC_RR && mtype == GSM48_MT_RR_PAG_RESP) + goto paging; + else if (pdisc == GSM48_PDISC_MM && mtype == GSM48_MT_MM_CM_SERV_REQ) { + is_emerg = is_cm_service_for_emerg(msg); + goto round_robin; + } else + goto round_robin; + +round_robin: + llist_for_each_entry(msc, &bsc->mscs, entry) { + if (!msc->msc_con->is_authenticated) + continue; + if (!is_emerg && msc->type != MSC_CON_TYPE_NORMAL) + continue; + if (is_emerg && !msc->allow_emerg) + continue; + + /* force round robin by moving it to the end */ + llist_move_tail(&msc->entry, &bsc->mscs); + return msc; + } + + return NULL; + +paging: + subscr = extract_sub(conn, msg); + + if (!subscr) { + LOGP(DMSC, LOGL_ERROR, "Got paged but no subscriber found.\n"); + return NULL; + } + + pag_msc = paging_get_data(conn->bts, subscr); + bsc_subscr_put(subscr); + + llist_for_each_entry(msc, &bsc->mscs, entry) { + if (msc != pag_msc) + continue; + + /* + * We don't check if the MSC is connected. In case it + * is not the connection will be dropped. + */ + + /* force round robin by moving it to the end */ + llist_move_tail(&msc->entry, &bsc->mscs); + return msc; + } + + LOGP(DMSC, LOGL_ERROR, "Got paged but no request found.\n"); + return NULL; +} + + +/** + * This is used to scan a message for extra functionality of the BSC. This + * includes scanning for location updating requests/acceptd and then send + * a welcome USSD message to the subscriber. + */ +int bsc_scan_bts_msg(struct gsm_subscriber_connection *conn, struct msgb *msg) +{ + struct gsm48_hdr *gh = msgb_l3(msg); + uint8_t pdisc = gsm48_hdr_pdisc(gh); + uint8_t mtype = gsm48_hdr_msg_type(gh); + + if (pdisc == GSM48_PDISC_MM) { + if (mtype == GSM48_MT_MM_LOC_UPD_REQUEST) + handle_lu_request(conn, msg); + } else if (pdisc == GSM48_PDISC_RR) { + if (mtype == GSM48_MT_RR_PAG_RESP) + handle_page_resp(conn, msg); + } + + return 0; +} + +static int send_welcome_ussd(struct gsm_subscriber_connection *conn) +{ + struct osmo_bsc_sccp_con *bsc_con; + + bsc_con = conn->sccp_con; + if (!bsc_con) { + LOGP(DMSC, LOGL_DEBUG, "No SCCP connection associated.\n"); + return 0; + } + + if (!bsc_con->msc->ussd_welcome_txt) { + LOGP(DMSC, LOGL_DEBUG, "No USSD Welcome text defined.\n"); + return 0; + } + + return BSS_SEND_USSD; +} + +int bsc_send_welcome_ussd(struct gsm_subscriber_connection *conn) +{ + bsc_send_ussd_notify(conn, 1, conn->sccp_con->msc->ussd_welcome_txt); + bsc_send_ussd_release_complete(conn); + + return 0; +} + +static int bsc_patch_mm_info(struct gsm_subscriber_connection *conn, + uint8_t *data, unsigned int length) +{ + struct tlv_parsed tp; + int parse_res; + struct gsm_bts *bts = conn->bts; + int tzunits; + uint8_t tzbsd = 0; + uint8_t dst = 0; + + parse_res = tlv_parse(&tp, &gsm48_mm_att_tlvdef, data, length, 0, 0); + if (parse_res <= 0 && parse_res != -3) + /* FIXME: -3 means unknown IE error, so this accepts messages + * with unknown IEs. But parsing has aborted with the unknown + * IE and the message is broken or parsed incompletely. */ + return 0; + + /* Is TZ patching enabled? */ + struct gsm_tz *tz = &bts->network->tz; + if (!tz->override) + return 0; + + /* Convert tz.hr and tz.mn to units */ + if (tz->hr < 0) { + tzunits = -tz->hr*4; + tzbsd |= 0x08; + } else + tzunits = tz->hr*4; + + tzunits = tzunits + (tz->mn/15); + + tzbsd |= (tzunits % 10)*0x10 + (tzunits / 10); + + /* Convert DST value */ + if (tz->dst >= 0 && tz->dst <= 2) + dst = tz->dst; + + if (TLVP_PRESENT(&tp, GSM48_IE_UTC)) { + LOGP(DMSC, LOGL_DEBUG, + "Changing 'Local time zone' from 0x%02x to 0x%02x.\n", + TLVP_VAL(&tp, GSM48_IE_UTC)[6], tzbsd); + ((uint8_t *)(TLVP_VAL(&tp, GSM48_IE_UTC)))[0] = tzbsd; + } + if (TLVP_PRESENT(&tp, GSM48_IE_NET_TIME_TZ)) { + LOGP(DMSC, LOGL_DEBUG, + "Changing 'Universal time and local time zone' TZ from " + "0x%02x to 0x%02x.\n", + TLVP_VAL(&tp, GSM48_IE_NET_TIME_TZ)[6], tzbsd); + ((uint8_t *)(TLVP_VAL(&tp, GSM48_IE_NET_TIME_TZ)))[6] = tzbsd; + } +#ifdef GSM48_IE_NET_DST + if (TLVP_PRESENT(&tp, GSM48_IE_NET_DST)) { + LOGP(DMSC, LOGL_DEBUG, + "Changing 'Network daylight saving time' from " + "0x%02x to 0x%02x.\n", + TLVP_VAL(&tp, GSM48_IE_NET_DST)[0], dst); + ((uint8_t *)(TLVP_VAL(&tp, GSM48_IE_NET_DST)))[0] = dst; + } +#endif + + return 0; +} + +static int has_core_identity(struct bsc_msc_data *msc) +{ + if (msc->core_mnc != -1) + return 1; + if (msc->core_mcc != -1) + return 1; + if (msc->core_lac != -1) + return 1; + if (msc->core_ci != -1) + return 1; + return 0; +} + +/** + * Messages coming back from the MSC. + */ +int bsc_scan_msc_msg(struct gsm_subscriber_connection *conn, struct msgb *msg) +{ + struct bsc_msc_data *msc; + struct gsm_network *net; + struct gsm48_loc_area_id *lai; + struct gsm48_hdr *gh; + uint8_t pdisc; + uint8_t mtype; + int length = msgb_l3len(msg); + + if (length < sizeof(*gh)) { + LOGP(DMSC, LOGL_ERROR, "GSM48 header does not fit.\n"); + return -1; + } + + gh = (struct gsm48_hdr *) msgb_l3(msg); + length -= (const char *)&gh->data[0] - (const char *)gh; + + pdisc = gsm48_hdr_pdisc(gh); + if (pdisc != GSM48_PDISC_MM) + return 0; + + mtype = gsm48_hdr_msg_type(gh); + net = conn->bts->network; + msc = conn->sccp_con->msc; + + if (mtype == GSM48_MT_MM_LOC_UPD_ACCEPT) { + if (has_core_identity(msc)) { + if (msgb_l3len(msg) >= sizeof(*gh) + sizeof(*lai)) { + /* overwrite LAI in the message */ + lai = (struct gsm48_loc_area_id *) &gh->data[0]; + gsm48_generate_lai(lai, net->country_code, + net->network_code, + conn->bts->location_area_code); + } + } + + if (conn->sccp_con->new_subscriber) + return send_welcome_ussd(conn); + return 0; + } else if (mtype == GSM48_MT_MM_INFO) { + bsc_patch_mm_info(conn, &gh->data[0], length); + } + + return 0; +} -- cgit v1.2.3