431 lines
14 KiB
C
431 lines
14 KiB
C
/* (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
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* (C) 2009-2011 by On-Waves
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* All Rights Reserved
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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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*/
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#include <osmocom/bsc/bsc_subscr_conn_fsm.h>
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#include <osmocom/bsc/osmo_bsc.h>
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#include <osmocom/bsc/bsc_msc_data.h>
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#include <osmocom/bsc/bsc_subscriber.h>
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#include <osmocom/bsc/debug.h>
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#include <osmocom/bsc/paging.h>
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#include <osmocom/bsc/gsm_08_08.h>
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#include <osmocom/bsc/codec_pref.h>
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#include <osmocom/bsc/gsm_04_08_rr.h>
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#include <osmocom/bsc/a_reset.h>
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#include <osmocom/gsm/protocol/gsm_08_08.h>
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#include <osmocom/gsm/gsm0808.h>
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#include <osmocom/gsm/mncc.h>
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#include <osmocom/gsm/gsm48.h>
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#include <osmocom/bsc/osmo_bsc_sigtran.h>
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#define LOG_COMPL_L3(pdisc, mtype, loglevel, format, args...) \
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LOGP(DRSL, loglevel, "%s %s: " format, gsm48_pdisc_name(pdisc), gsm48_pdisc_msgtype_name(pdisc, mtype), ##args)
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/* Check if we have a proper connection to the MSC */
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static bool msc_connected(struct gsm_subscriber_connection *conn)
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{
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/* No subscriber conn at all */
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if (!conn)
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return false;
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/* Connection to MSC not established */
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if (!conn->sccp.msc)
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return false;
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/* Reset procedure not (yet) executed */
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if (a_reset_conn_ready(conn->sccp.msc) == false)
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return false;
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return true;
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}
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/*! BTS->MSC: tell MSC a SAPI was not established. */
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void bsc_sapi_n_reject(struct gsm_subscriber_connection *conn, int dlci)
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{
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int rc;
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struct msgb *resp;
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if (!msc_connected(conn))
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return;
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LOGP(DMSC, LOGL_NOTICE, "Tx MSC SAPI N REJECT DLCI=0x%02x\n", dlci);
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resp = gsm0808_create_sapi_reject(dlci);
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rate_ctr_inc(&conn->sccp.msc->msc_ctrs->ctr[MSC_CTR_BSSMAP_TX_DT1_SAPI_N_REJECT]);
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rc = osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_TX_SCCP, resp);
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if (rc != 0)
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msgb_free(resp);
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}
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/*! MS->MSC: Tell MSC that ciphering has been enabled. */
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void bsc_cipher_mode_compl(struct gsm_subscriber_connection *conn, struct msgb *msg, uint8_t chosen_encr)
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{
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int rc;
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struct msgb *resp;
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if (!msc_connected(conn))
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return;
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LOGP(DMSC, LOGL_DEBUG, "CIPHER MODE COMPLETE from MS, forwarding to MSC\n");
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resp = gsm0808_create_cipher_complete(msg, chosen_encr);
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rate_ctr_inc(&conn->sccp.msc->msc_ctrs->ctr[MSC_CTR_BSSMAP_TX_DT1_CIPHER_COMPLETE]);
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rc = osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_TX_SCCP, resp);
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if (rc != 0)
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msgb_free(resp);
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}
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/* 9.2.5 CM service accept */
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int gsm48_tx_mm_serv_ack(struct gsm_subscriber_connection *conn)
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{
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struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 SERV ACK");
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struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
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msg->lchan = conn->lchan;
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gh->proto_discr = GSM48_PDISC_MM;
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gh->msg_type = GSM48_MT_MM_CM_SERV_ACC;
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DEBUGP(DMM, "-> CM SERVICE ACK\n");
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gscon_submit_rsl_dtap(conn, msg, 0, 0);
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return 0;
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}
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static bool is_cm_service_for_emerg(struct msgb *msg)
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{
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struct gsm48_service_request *cm;
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struct gsm48_hdr *gh = msgb_l3(msg);
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if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*cm)) {
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LOGP(DMSC, LOGL_ERROR, "CM ServiceRequest does not fit.\n");
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return false;
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}
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cm = (struct gsm48_service_request *) &gh->data[0];
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return cm->cm_service_type == GSM48_CMSERV_EMERGENCY;
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}
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static bool is_msc_usable(struct bsc_msc_data *msc, bool is_emerg)
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{
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if (is_emerg && !msc->allow_emerg)
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return false;
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if (!a_reset_conn_ready(msc))
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return false;
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return true;
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}
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/* Decide which MSC to forward this Complete Layer 3 request to.
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* a) If the subscriber was previously paged from a particular MSC, that MSC shall receive the Paging Response.
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* b) If the message contains an NRI indicating a particular MSC and the MSC is connected, that MSC shall handle this
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* conn.
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* c) All other cases distribute the messages across connected MSCs in a round-robin fashion.
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*/
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static struct bsc_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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struct gsm_network *net = conn->network;
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struct gsm48_hdr *gh;
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int8_t pdisc;
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uint8_t mtype;
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struct osmo_mobile_identity mi;
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struct bsc_msc_data *msc;
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struct bsc_msc_data *msc_target = NULL;
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struct bsc_msc_data *msc_round_robin_next = NULL;
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struct bsc_msc_data *msc_round_robin_first = NULL;
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uint8_t round_robin_next_nr;
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struct bsc_subscr *subscr;
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bool is_emerg = false;
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if (msgb_l3len(msg) < sizeof(*gh)) {
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LOGP(DMSC, LOGL_ERROR, "There is no GSM48 header here.\n");
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return NULL;
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}
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gh = msgb_l3(msg);
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pdisc = gsm48_hdr_pdisc(gh);
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mtype = gsm48_hdr_msg_type(gh);
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is_emerg = (pdisc == GSM48_PDISC_MM && mtype == GSM48_MT_MM_CM_SERV_REQ) && is_cm_service_for_emerg(msg);
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if (osmo_mobile_identity_decode_from_l3(&mi, msg, false)) {
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LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "Cannot extract Mobile Identity: %s\n",
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msgb_hexdump_c(OTC_SELECT, msg));
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/* There is no Mobile Identity to pick a matching MSC from. Likely this is an invalid Complete Layer 3
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* message that deserves to be rejected. However, the current state of our ttcn3 tests does send invalid
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* Layer 3 Info in some tests and expects osmo-bsc to not care about that. So, changing the behavior to
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* rejecting on missing MI causes test failure and, if at all, should happen in a separate patch.
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* See e.g. BSC_Tests.TC_chan_rel_rll_rel_ind: "dt := f_est_dchan('23'O, 23, '00010203040506'O);" */
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}
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/* Has the subscriber been paged from a connected MSC? */
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if (pdisc == GSM48_PDISC_RR && mtype == GSM48_MT_RR_PAG_RESP) {
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subscr = bsc_subscr_find_by_mi(conn->network->bsc_subscribers, &mi);
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if (subscr) {
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msc_target = paging_get_msc(conn_get_bts(conn), subscr);
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bsc_subscr_put(subscr);
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if (is_msc_usable(msc_target, is_emerg))
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return msc_target;
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msc_target = NULL;
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}
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}
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/* TODO: extract NRI from MI */
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/* Iterate MSCs to find one that matches the extracted NRI, and the next round-robin target for the case no NRI
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* match is found. */
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round_robin_next_nr = (is_emerg ? net->mscs_round_robin_next_emerg_nr : net->mscs_round_robin_next_nr);
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llist_for_each_entry(msc, &net->mscs, entry) {
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if (!is_msc_usable(msc, is_emerg))
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continue;
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/* TODO: return msc when extracted NRI matches this MSC */
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/* Figure out the next round-robin MSC. The MSCs may appear unsorted in net->mscs. Make sure to linearly
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* round robin the MSCs by number: pick the lowest msc->nr >= round_robin_next_nr, and also remember the
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* lowest available msc->nr to wrap back to that in case no next MSC is left. */
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if (!msc_round_robin_first || msc->nr < msc_round_robin_first->nr)
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msc_round_robin_first = msc;
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if (msc->nr >= round_robin_next_nr
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&& (!msc_round_robin_next || msc->nr < msc_round_robin_next->nr))
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msc_round_robin_next = msc;
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}
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/* No dedicated MSC found. Choose by round-robin.
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* If msc_round_robin_next is NULL, there are either no more MSCs at/after mscs_round_robin_next_nr, or none of
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* them are usable -- wrap to the start. */
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msc_target = msc_round_robin_next ? : msc_round_robin_first;
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if (!msc_target) {
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LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "%s%s: No suitable MSC for this Complete Layer 3 request found\n",
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osmo_mobile_identity_to_str_c(OTC_SELECT, &mi), is_emerg ? " FOR EMERGENCY CALL" : "");
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return NULL;
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}
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/* An MSC was picked by round-robin, so update the next round-robin nr to pick */
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if (is_emerg)
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net->mscs_round_robin_next_emerg_nr = msc_target->nr + 1;
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else
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net->mscs_round_robin_next_nr = msc_target->nr + 1;
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return msc_target;
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}
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static int handle_page_resp(struct gsm_subscriber_connection *conn, struct msgb *msg)
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{
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struct osmo_mobile_identity mi;
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struct bsc_subscr *subscr = NULL;
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if (osmo_mobile_identity_decode_from_l3(&mi, msg, false)) {
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LOGP(DRSL, LOGL_ERROR, "Unable to extract Mobile Identity from Paging Response\n");
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return -1;
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}
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subscr = bsc_subscr_find_by_mi(conn->network->bsc_subscribers, &mi);
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if (!subscr) {
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LOGP(DMSC, LOGL_ERROR, "Non active subscriber got paged.\n");
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rate_ctr_inc(&conn->lchan->ts->trx->bts->bts_ctrs->ctr[BTS_CTR_PAGING_NO_ACTIVE_PAGING]);
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rate_ctr_inc(&conn->network->bsc_ctrs->ctr[BSC_CTR_PAGING_NO_ACTIVE_PAGING]);
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return -1;
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}
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paging_request_stop(&conn->network->bts_list, conn_get_bts(conn), subscr, conn,
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msg);
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bsc_subscr_put(subscr);
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return 0;
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}
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/* TS 04.08 sec 9.2.15 "Location updating request" */
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static void handle_lu_request(struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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struct gsm48_hdr *gh;
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struct gsm48_loc_upd_req *lu;
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int8_t rc8;
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struct gsm_bts *bts = conn_get_bts(conn);
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if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*lu)) {
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LOGP(DMSC, LOGL_ERROR, "LU too small to look at: %u\n", msgb_l3len(msg));
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return;
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}
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gh = msgb_l3(msg);
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lu = (struct gsm48_loc_upd_req *) gh->data;
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rc8 = osmo_gsm48_rfpowercap2powerclass(bts->band, lu->classmark1.pwr_lev);
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if (rc8 < 0) {
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LOGP(DMSC, LOGL_NOTICE,
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"Unable to decode RF power capability %x from classmark1 during LU.\n",
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lu->classmark1.pwr_lev);
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rc8 = 0;
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}
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conn_update_ms_power_class(conn, rc8);
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}
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/* TS 04.08 sec 9.2.15 "Location updating request" */
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static void handle_cm_serv_req(struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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struct gsm48_hdr *gh;
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struct gsm48_service_request *serv_req;
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struct gsm48_classmark2* cm2;
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int8_t rc8;
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struct gsm_bts *bts = conn_get_bts(conn);
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if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*serv_req)) {
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LOGP(DMSC, LOGL_ERROR, "CM Serv Req too small to look at: %u\n", msgb_l3len(msg));
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return;
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}
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gh = msgb_l3(msg);
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serv_req = (struct gsm48_service_request *) gh->data;
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cm2 = (struct gsm48_classmark2*)(((uint8_t*)&serv_req->classmark)+1);
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/* FIXME: one classmark2 is available in libosmocore:
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cm2 = &serv_req->classmark2; */
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rc8 = osmo_gsm48_rfpowercap2powerclass(bts->band, cm2->pwr_lev);
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if (rc8 < 0) {
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LOGP(DMSC, LOGL_NOTICE,
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"Unable to decode RF power capability %x from classmark2 during CM Service Req.\n",
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cm2->pwr_lev);
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rc8 = 0;
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}
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conn_update_ms_power_class(conn, rc8);
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}
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int bsc_scan_bts_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
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{
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struct gsm48_hdr *gh = msgb_l3(msg);
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uint8_t pdisc = gsm48_hdr_pdisc(gh);
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uint8_t mtype = gsm48_hdr_msg_type(gh);
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if (pdisc == GSM48_PDISC_MM) {
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if (mtype == GSM48_MT_MM_LOC_UPD_REQUEST)
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handle_lu_request(conn, msg);
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else if(mtype == GSM48_MT_MM_CM_SERV_REQ)
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handle_cm_serv_req(conn, msg);
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} else if (pdisc == GSM48_PDISC_RR) {
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if (mtype == GSM48_MT_RR_PAG_RESP)
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handle_page_resp(conn, msg);
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}
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return 0;
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}
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/*! MS->MSC: New MM context with L3 payload. */
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int bsc_compl_l3(struct gsm_subscriber_connection *conn, struct msgb *msg, uint16_t chosen_channel)
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{
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struct bsc_msc_data *msc;
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struct msgb *resp;
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struct gsm0808_speech_codec_list scl;
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int rc = -2;
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log_set_context(LOG_CTX_BSC_SUBSCR, conn->bsub);
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LOGP(DMSC, LOGL_INFO, "Tx MSC COMPL L3\n");
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/* find the MSC link we want to use */
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msc = bsc_find_msc(conn, msg);
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if (!msc) {
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LOGP(DMSC, LOGL_ERROR, "Failed to find a MSC for a connection.\n");
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rc = -1;
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goto early_fail;
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}
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/* allocate resource for a new connection */
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if (osmo_bsc_sigtran_new_conn(conn, msc) != BSC_CON_SUCCESS)
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goto early_fail;
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bsc_scan_bts_msg(conn, msg);
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if (gscon_is_aoip(conn)) {
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gen_bss_supported_codec_list(&scl, msc, conn_get_bts(conn));
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if (scl.len > 0)
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resp = gsm0808_create_layer3_2(msg, cgi_for_msc(conn->sccp.msc, conn_get_bts(conn)), &scl);
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else {
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/* Note: 3GPP TS 48.008 3.2.1.32, COMPLETE LAYER 3 INFORMATION clearly states that
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* Codec List (BSS Supported) shall be included, if the radio access network
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* supports an IP based user plane interface. It may be intentional that the
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* current configuration does not support any voice codecs, in those cases the
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* network does not support an IP based user plane interface, and therefore the
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* Codec List (BSS Supported) IE can be left out in those situations. */
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resp = gsm0808_create_layer3_2(msg, cgi_for_msc(conn->sccp.msc, conn_get_bts(conn)), NULL);
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}
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} else
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resp = gsm0808_create_layer3_2(msg, cgi_for_msc(conn->sccp.msc, conn_get_bts(conn)), NULL);
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if (resp)
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rc = osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_A_CONN_REQ, resp);
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else
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LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
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early_fail:
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log_set_context(LOG_CTX_BSC_SUBSCR, NULL);
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return rc;
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}
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/*! MS->BSC/MSC: Um L3 message. */
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void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct msgb *msg)
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{
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log_set_context(LOG_CTX_BSC_SUBSCR, conn->bsub);
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if (!msc_connected(conn))
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goto done;
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LOGP(DMSC, LOGL_INFO, "Tx MSC DTAP LINK_ID=0x%02x\n", link_id);
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bsc_scan_bts_msg(conn, msg);
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/* Store link_id in msg->cb */
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OBSC_LINKID_CB(msg) = link_id;
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osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_MO_DTAP, msg);
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done:
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log_set_context(LOG_CTX_BSC_SUBSCR, NULL);
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return;
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}
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/*! BSC->MSC: Classmark Update. */
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void bsc_cm_update(struct gsm_subscriber_connection *conn,
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const uint8_t *cm2, uint8_t cm2_len,
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const uint8_t *cm3, uint8_t cm3_len)
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{
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struct gsm48_classmark2 *cm2_parsed = (struct gsm48_classmark2 *)cm2;
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int8_t rc8;
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int rc;
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struct msgb *resp;
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struct gsm_bts *bts = conn_get_bts(conn);
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rc8 = osmo_gsm48_rfpowercap2powerclass(bts->band, cm2_parsed->pwr_lev);
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if (rc8 < 0) {
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LOGP(DMSC, LOGL_NOTICE,
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"Unable to decode RF power capability %x from classmark1 during CM Update.\n",
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cm2_parsed->pwr_lev);
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rc8 = 0;
|
|
}
|
|
conn_update_ms_power_class(conn, rc8);
|
|
|
|
if (!msc_connected(conn))
|
|
return;
|
|
|
|
rate_ctr_inc(&conn->sccp.msc->msc_ctrs->ctr[MSC_CTR_BSSMAP_TX_DT1_CLASSMARK_UPDATE]);
|
|
resp = gsm0808_create_classmark_update(cm2, cm2_len, cm3, cm3_len);
|
|
rc = osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_TX_SCCP, resp);
|
|
if (rc != 0)
|
|
msgb_free(resp);
|
|
}
|