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osmo-bts/src/osmo-bts-virtual/l1_if.c

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/* Virtual BTS layer 1 primitive handling and interface
*
* Copyright (C) 2015-2017 Harald Welte <laforge@gnumonks.org>
* Copyright (C) 2017 Sebastian Stumpf <sebastian.stumpf87@googlemail.com>
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/bits.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/gsmtap.h>
#include <osmocom/core/gsmtap_util.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/gsm/rsl.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/oml.h>
#include <osmo-bts/rsl.h>
#include <osmo-bts/l1sap.h>
#include <osmo-bts/bts_model.h>
#include <osmo-bts/phy_link.h>
#include <osmo-bts/amr.h>
#include <osmo-bts/abis.h>
#include <osmo-bts/scheduler.h>
#include "virtual_um.h"
extern int vbts_sched_start(struct gsm_bts *bts);
static struct phy_instance *phy_instance_by_arfcn(struct phy_link *plink, uint16_t arfcn)
{
struct phy_instance *pinst;
llist_for_each_entry(pinst, &plink->instances, list) {
if (pinst->trx && pinst->trx->arfcn == arfcn)
return pinst;
}
return NULL;
}
static int l1if_process_meas_res(struct gsm_bts_trx *trx, uint8_t tn, uint32_t fn, uint8_t chan_nr,
int n_errors, int n_bits_total, float rssi, float toa);
/**
* Callback to handle incoming messages from the MS.
* The incoming message should be GSM_TAP encapsulated.
* TODO: implement all channels
*/
static void virt_um_rcv_cb(struct virt_um_inst *vui, struct msgb *msg)
{
struct phy_link *plink = (struct phy_link *)vui->priv;
struct phy_instance *pinst;
if (!msg) {
pinst = phy_instance_by_num(plink, 0);
bts_shutdown(pinst->trx->bts, "VirtPHY read socket died\n");
return;
}
struct gsmtap_hdr *gh = msgb_l1(msg);
uint32_t fn = ntohl(gh->frame_number); /* frame number of the rcv msg */
uint16_t arfcn = ntohs(gh->arfcn); /* arfcn of the cell we currently camp on */
uint8_t gsmtap_chantype = gh->sub_type; /* gsmtap channel type */
uint8_t signal_dbm = gh->signal_dbm; /* signal strength in dBm */
//uint8_t snr = gh->snr_db; /* signal noise ratio in dB */
uint8_t subslot = gh->sub_slot; /* multiframe subslot to send msg in (tch -> 0-26, bcch/ccch -> 0-51) */
uint8_t timeslot = gh->timeslot; /* tdma timeslot to send in (0-7) */
uint8_t rsl_chantype; /* rsl chan type (8.58, 9.3.1) */
uint8_t link_id; /* rsl link id tells if this is an ssociated or dedicated link */
uint8_t chan_nr; /* encoded rsl channel type, timeslot and mf subslot */
struct osmo_phsap_prim l1sap;
memset(&l1sap, 0, sizeof(l1sap));
/* get rid of l1 gsmtap hdr */
msg->l2h = msgb_pull(msg, sizeof(*gh));
/* convert gsmtap chan to RSL chan and link id */
chantype_gsmtap2rsl(gsmtap_chantype, &rsl_chantype, &link_id);
chan_nr = rsl_enc_chan_nr(rsl_chantype, subslot, timeslot);
/* ... or not uplink */
if (!(arfcn & GSMTAP_ARFCN_F_UPLINK)) {
LOGPFN(DL1P, LOGL_NOTICE, fn, "Ignoring incoming msg - no uplink flag\n");
goto nomessage;
}
/* Generally ignore all msgs that are either not received with the right ARFCN... */
pinst = phy_instance_by_arfcn(plink, arfcn & GSMTAP_ARFCN_MASK);
if (!pinst)
goto nomessage;
/* switch case with removed ACCH flag */
switch ((gsmtap_chantype & ~GSMTAP_CHANNEL_ACCH) & 0xff) {
case GSMTAP_CHANNEL_RACH:
/* generate primitive for upper layer
* see 04.08 - 3.3.1.3.1: the IMMEDIATE_ASSIGNMENT coming back from the network has to be
* sent with the same ra reference as in the CHANNEL_REQUEST that was received */
osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_PH_RACH, PRIM_OP_INDICATION, msg);
l1sap.u.rach_ind.chan_nr = chan_nr;
/* TODO: 11bit RACH */
l1sap.u.rach_ind.ra = msgb_pull_u8(msg); /* directly after gh hdr comes ra */
l1sap.u.rach_ind.acc_delay = 0; /* probably not used in virt um */
l1sap.u.rach_ind.is_11bit = 0;
l1sap.u.rach_ind.fn = fn;
/* we don't really know which RACH burst type the virtual MS is using, as this field is not
* part of information present in the GSMTAP header. So we simply report all of them as 0 */
l1sap.u.rach_ind.burst_type = GSM_L1_BURST_TYPE_ACCESS_0;
l1sap.u.rach_ind.lqual_cb = 10 * signal_dbm; /* Link quality in centiBel = 10 * dB. */
break;
case GSMTAP_CHANNEL_TCH_F:
case GSMTAP_CHANNEL_TCH_H:
/* This is TCH signalling, for voice frames see GSMTAP_CHANNEL_VOICE */
case GSMTAP_CHANNEL_SDCCH4:
case GSMTAP_CHANNEL_SDCCH8:
case GSMTAP_CHANNEL_PACCH:
case GSMTAP_CHANNEL_PDCH:
case GSMTAP_CHANNEL_PTCCH:
osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_PH_DATA,
PRIM_OP_INDICATION, msg);
l1sap.u.data.chan_nr = chan_nr;
l1sap.u.data.link_id = link_id;
l1sap.u.data.fn = fn;
l1sap.u.data.rssi = 0; /* Radio Signal Strength Indicator. Best -> 0 */
l1sap.u.data.ber10k = 0; /* Bit Error Rate in 0.01%. Best -> 0 */
l1sap.u.data.ta_offs_256bits = 0; /* Burst time of arrival in quarter bits. Probably used for Timing Advance calc. Best -> 0 */
l1sap.u.data.lqual_cb = 10 * signal_dbm; /* Link quality in centiBel = 10 * dB. */
l1sap.u.data.pdch_presence_info = PRES_INFO_BOTH;
l1if_process_meas_res(pinst->trx, timeslot, fn, chan_nr, 0, 0, 0, 0);
break;
case GSMTAP_CHANNEL_VOICE_F:
case GSMTAP_CHANNEL_VOICE_H:
/* the first byte indicates the type of voice codec (gsmtap_um_voice_type) */
msg->l2h = msgb_pull(msg, 1);
osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_TCH, PRIM_OP_INDICATION, msg);
l1sap.u.tch.chan_nr = chan_nr;
l1sap.u.tch.fn = fn;
l1sap.u.tch.rssi = 0; /* Radio Signal Strength Indicator. Best -> 0 */
l1sap.u.tch.ber10k = 0; /* Bit Error Rate in 0.01%. Best -> 0 */
l1sap.u.tch.ta_offs_256bits = 0; /* Burst time of arrival in quarter bits. Probably used for Timing Advance calc. Best -> 0 */
l1sap.u.tch.lqual_cb = 10 * signal_dbm; /* Link quality in centiBel = 10 * dB. */
l1if_process_meas_res(pinst->trx, timeslot, fn, chan_nr, 0, 0, 0, 0);
break;
case GSMTAP_CHANNEL_AGCH:
case GSMTAP_CHANNEL_PCH:
case GSMTAP_CHANNEL_BCCH:
LOGPFN(DL1P, LOGL_NOTICE, fn, "Ignore incoming msg - channel type downlink only!\n");
goto nomessage;
case GSMTAP_CHANNEL_SDCCH:
case GSMTAP_CHANNEL_CCCH:
case GSMTAP_CHANNEL_CBCH51:
case GSMTAP_CHANNEL_CBCH52:
LOGPFN(DL1P, LOGL_NOTICE, fn, "Ignore incoming msg - channel type not supported!\n");
goto nomessage;
default:
LOGPFN(DL1P, LOGL_NOTICE, fn, "Ignore incoming msg - channel type unknown\n");
goto nomessage;
}
/* forward primitive, lsap takes ownership of the msgb. */
l1sap_up(pinst->trx, &l1sap);
DEBUGPFN(DL1P, fn, "Message forwarded to layer 2.\n");
return;
nomessage:
talloc_free(msg);
}
/* called by common part once OML link is established */
int bts_model_oml_estab(struct gsm_bts *bts)
{
struct phy_instance *pinst = trx_phy_instance(bts->c0);
if (vbts_sched_start(pinst->trx->bts) < 0)
return -ENOLINK;
/* Only start the scheduler for the transceiver on C0.
* If we have multiple transceivers, CCCH is always on C0
* and has to be auto active */
pinst->trx->ts[0].lchan[CCCH_LCHAN].rel_act_kind = LCHAN_REL_ACT_OML;
/* Other TRX are activated via OML by a PRIM_INFO_MODIFY / PRIM_INFO_ACTIVATE */
lchan_set_state(&pinst->trx->ts[0].lchan[CCCH_LCHAN], LCHAN_S_ACTIVE);
return 0;
}
/* called by bts_main to initialize physical link */
int bts_model_phy_link_open(struct phy_link *plink)
{
struct phy_instance *pinst;
//OSMO_ASSERT(plink->type == PHY_LINK_T_VIRTUAL);
if (plink->u.virt.virt_um)
virt_um_destroy(plink->u.virt.virt_um);
phy_link_state_set(plink, PHY_LINK_CONNECTING);
plink->u.virt.virt_um = virt_um_init(plink, plink->u.virt.ms_mcast_group, plink->u.virt.ms_mcast_port,
plink->u.virt.bts_mcast_group, plink->u.virt.bts_mcast_port,
plink->u.virt.ttl, plink->u.virt.mcast_dev, virt_um_rcv_cb);
if (!plink->u.virt.virt_um) {
phy_link_state_set(plink, PHY_LINK_SHUTDOWN);
return -1;
}
/* set back reference to plink */
plink->u.virt.virt_um->priv = plink;
/* iterate over list of PHY instances and initialize the scheduler */
llist_for_each_entry(pinst, &plink->instances, list) {
if (pinst->trx == NULL)
continue;
trx_sched_init(pinst->trx);
}
/* this will automatically update the MO state of all associated TRX objects */
phy_link_state_set(plink, PHY_LINK_CONNECTED);
return 0;
}
/*
* primitive handling
*/
/* enable ciphering */
static int l1if_set_ciphering(struct gsm_lchan *lchan, uint8_t chan_nr, int downlink)
{
/* ciphering already enabled in both directions */
if (lchan->ciph_state == LCHAN_CIPH_RXTX_CONF)
return -EINVAL;
if (!downlink) {
/* set uplink */
trx_sched_set_cipher(lchan, chan_nr, false);
lchan->ciph_state = LCHAN_CIPH_RX_CONF;
} else {
/* set downlink and also set uplink, if not already */
if (lchan->ciph_state != LCHAN_CIPH_RX_CONF)
trx_sched_set_cipher(lchan, chan_nr, false);
trx_sched_set_cipher(lchan, chan_nr, true);
lchan->ciph_state = LCHAN_CIPH_RXTX_CONF;
}
return 0;
}
static int mph_info_chan_confirm(struct gsm_bts_trx *trx, uint8_t chan_nr,
enum osmo_mph_info_type type, uint8_t cause)
{
struct osmo_phsap_prim l1sap;
memset(&l1sap, 0, sizeof(l1sap));
osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_MPH_INFO, PRIM_OP_CONFIRM,
NULL);
l1sap.u.info.type = type;
l1sap.u.info.u.act_cnf.chan_nr = chan_nr;
l1sap.u.info.u.act_cnf.cause = cause;
return l1sap_up(trx, &l1sap);
}
int l1if_mph_time_ind(struct gsm_bts *bts, uint32_t fn)
{
struct osmo_phsap_prim l1sap;
memset(&l1sap, 0, sizeof(l1sap));
osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_MPH_INFO,
PRIM_OP_INDICATION, NULL);
l1sap.u.info.type = PRIM_INFO_TIME;
l1sap.u.info.u.time_ind.fn = fn;
if (!bts->c0)
return -EINVAL;
return l1sap_up(bts->c0, &l1sap);
}
static void l1if_fill_meas_res(struct osmo_phsap_prim *l1sap, uint8_t chan_nr, float ta,
float ber, float rssi, uint32_t fn)
{
memset(l1sap, 0, sizeof(*l1sap));
osmo_prim_init(&l1sap->oph, SAP_GSM_PH, PRIM_MPH_INFO,
PRIM_OP_INDICATION, NULL);
l1sap->u.info.type = PRIM_INFO_MEAS;
l1sap->u.info.u.meas_ind.chan_nr = chan_nr;
l1sap->u.info.u.meas_ind.ta_offs_256bits = (int16_t)(ta*4);
l1sap->u.info.u.meas_ind.ber10k = (unsigned int) (ber * 10000);
l1sap->u.info.u.meas_ind.inv_rssi = (uint8_t) (rssi * -1);
l1sap->u.info.u.meas_ind.fn = fn;
}
static int l1if_process_meas_res(struct gsm_bts_trx *trx, uint8_t tn, uint32_t fn, uint8_t chan_nr,
int n_errors, int n_bits_total, float rssi, float toa)
{
struct gsm_lchan *lchan = &trx->ts[tn].lchan[l1sap_chan2ss(chan_nr)];
struct osmo_phsap_prim l1sap;
/* 100% BER is n_bits_total is 0 */
float ber = n_bits_total==0 ? 1.0 : (float)n_errors / (float)n_bits_total;
DEBUGPFN(DMEAS, fn, "RX L1 frame %s chan_nr=0x%02x MS pwr=%ddBm rssi=%.1f dBFS "
"ber=%.2f%% (%d/%d bits) L1_ta=%d ta_ctrl.current=%d toa=%.2f\n",
gsm_lchan_name(lchan), chan_nr, ms_pwr_dbm(lchan->ts->trx->bts->band, lchan->ms_power_ctrl.max),
rssi, ber*100, n_errors, n_bits_total, lchan->meas.l1_info.ta, lchan->ta_ctrl.current, toa);
l1if_fill_meas_res(&l1sap, chan_nr, lchan->ta_ctrl.current + toa, ber, rssi, fn);
return l1sap_up(trx, &l1sap);
}
/* primitive from common part */
int bts_model_l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
{
struct msgb *msg = l1sap->oph.msg;
uint8_t chan_nr;
int rc = 0;
struct gsm_lchan *lchan;
switch (OSMO_PRIM_HDR(&l1sap->oph)) {
case OSMO_PRIM(PRIM_PH_DATA, PRIM_OP_REQUEST):
if (!msg)
break;
/* put data into scheduler's queue */
return trx_sched_ph_data_req(trx, l1sap);
case OSMO_PRIM(PRIM_TCH, PRIM_OP_REQUEST):
if (!msg)
break;
/* put data into scheduler's queue */
return trx_sched_tch_req(trx, l1sap);
case OSMO_PRIM(PRIM_MPH_INFO, PRIM_OP_REQUEST):
if (l1sap->u.info.type == PRIM_INFO_ACT_CIPH)
chan_nr = l1sap->u.info.u.ciph_req.chan_nr;
else /* u.act_req used by PRIM_INFO_{ACTIVATE,DEACTIVATE,MODIFY} */
chan_nr = l1sap->u.info.u.act_req.chan_nr;
lchan = get_lchan_by_chan_nr(trx, chan_nr);
if (OSMO_UNLIKELY(lchan == NULL)) {
LOGP(DL1C, LOGL_ERROR,
"Rx MPH-INFO.req (type=0x%02x) for non-existent lchan (%s)\n",
l1sap->u.info.type, rsl_chan_nr_str(chan_nr));
rc = -ENODEV;
break;
}
switch (l1sap->u.info.type) {
case PRIM_INFO_ACT_CIPH:
if (l1sap->u.info.u.ciph_req.uplink)
l1if_set_ciphering(lchan, chan_nr, 0);
if (l1sap->u.info.u.ciph_req.downlink)
l1if_set_ciphering(lchan, chan_nr, 1);
break;
case PRIM_INFO_ACTIVATE:
if ((chan_nr & 0xE0) == 0x80) {
LOGPLCHAN(lchan, DL1C, LOGL_ERROR, "Cannot activate"
" channel %s\n", rsl_chan_nr_str(chan_nr));
break;
}
/* activate dedicated channel */
trx_sched_set_lchan(lchan, chan_nr, LID_DEDIC, true);
/* activate associated channel */
trx_sched_set_lchan(lchan, chan_nr, LID_SACCH, true);
/* set mode */
trx_sched_set_mode(lchan->ts, chan_nr,
lchan->rsl_cmode, lchan->tch_mode,
lchan->tch.amr_mr.num_modes,
lchan->tch.amr_mr.mode[0].mode,
lchan->tch.amr_mr.mode[1].mode,
lchan->tch.amr_mr.mode[2].mode,
lchan->tch.amr_mr.mode[3].mode,
amr_get_initial_mode(lchan),
(lchan->ho.active == 1));
/* set lchan active */
lchan_set_state(lchan, LCHAN_S_ACTIVE);
/* set initial ciphering */
l1if_set_ciphering(lchan, chan_nr, 0);
l1if_set_ciphering(lchan, chan_nr, 1);
if (lchan->encr.alg_id)
lchan->ciph_state = LCHAN_CIPH_RXTX_CONF;
else
lchan->ciph_state = LCHAN_CIPH_NONE;
/* confirm */
mph_info_chan_confirm(trx, chan_nr, PRIM_INFO_ACTIVATE, 0);
break;
case PRIM_INFO_MODIFY:
/* change mode */
trx_sched_set_mode(lchan->ts, chan_nr,
lchan->rsl_cmode, lchan->tch_mode,
lchan->tch.amr_mr.num_modes,
lchan->tch.amr_mr.mode[0].mode,
lchan->tch.amr_mr.mode[1].mode,
lchan->tch.amr_mr.mode[2].mode,
lchan->tch.amr_mr.mode[3].mode,
amr_get_initial_mode(lchan),
0);
break;
case PRIM_INFO_DEACTIVATE:
if ((chan_nr & 0xE0) == 0x80) {
LOGPLCHAN(lchan, DL1C, LOGL_ERROR, "Cannot deactivate"
" channel %s\n", rsl_chan_nr_str(chan_nr));
break;
}
/* deactivate associated channel */
trx_sched_set_lchan(lchan, chan_nr, LID_SACCH, false);
if (!l1sap->u.info.u.act_req.sacch_only) {
/* set lchan inactive */
lchan_set_state(lchan, LCHAN_S_NONE);
/* deactivate dedicated channel */
trx_sched_set_lchan(lchan, chan_nr, LID_DEDIC, false);
/* confirm only on dedicated channel */
mph_info_chan_confirm(trx, chan_nr,
PRIM_INFO_DEACTIVATE, 0);
lchan->ciph_state = 0; /* FIXME: do this in common/\*.c */
}
break;
default:
LOGP(DL1C, LOGL_NOTICE, "unknown MPH-INFO.req %d\n",
l1sap->u.info.type);
rc = -EINVAL;
goto done;
}
break;
default:
LOGP(DL1C, LOGL_NOTICE, "unknown prim %d op %d\n",
l1sap->oph.primitive, l1sap->oph.operation);
rc = -EINVAL;
goto done;
}
done:
if (msg)
msgb_free(msg);
return rc;
}
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