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osmo-bts/src/osmo-bts-bb/l1ctl.c

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/* Layer1 control code, talking L1CTL protocol with L1 on the phone */
/* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2011 by Andreas Eversberg <jolly@eversberg.eu>
*
* All Rights Reserved
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <l1ctl_proto.h>
#include <osmocore/signal.h>
#include <osmocore/logging.h>
#include <osmocore/timer.h>
#include <osmocore/msgb.h>
#include <osmocore/tlv.h>
#include <osmocore/gsm_utils.h>
#include <osmocore/gsmtap_util.h>
#include <osmocore/protocol/gsm_04_08.h>
#include <osmocore/protocol/gsm_08_58.h>
#include <osmocore/rsl.h>
#include <osmocom/bb/common/l1ctl.h>
#include <osmocom/bb/common/osmocom_data.h>
#include <osmocom/bb/common/l1l2_interface.h>
#include <osmocom/bb/common/lapdm.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/abis.h>
#include <osmo-bts/rtp.h>
#include <osmo-bts/bts.h>
static struct msgb *osmo_l1_alloc(uint8_t msg_type)
{
struct l1ctl_hdr *l1h;
struct msgb *msg = msgb_alloc_headroom(256, 4, "osmo_l1");
if (!msg) {
LOGP(DL1C, LOGL_ERROR, "Failed to allocate memory.\n");
return NULL;
}
msg->l1h = msgb_put(msg, sizeof(*l1h));
l1h = (struct l1ctl_hdr *) msg->l1h;
l1h->msg_type = msg_type;
return msg;
}
static int osmo_make_band_arfcn(struct osmocom_ms *ms, uint16_t arfcn)
{
/* TODO: Include the band */
return arfcn;
}
/* Receive L1CTL_DATA_IND (Data Indication from L1) */
int rx_ph_data_ind(struct osmocom_ms *ms, struct msgb *msg)
{
struct l1ctl_info_dl *dl, dl_cpy;
struct l1ctl_data_ind *ccch;
struct lapdm_entity *le;
struct rx_meas_stat *meas = &ms->meas;
uint8_t chan_type, chan_ts, chan_ss;
uint8_t gsmtap_chan_type;
struct gsm_time tm;
struct osmobts_ms *bts_ms = container_of(ms, struct osmobts_ms, ms);
struct osmobts_lchan *lchan;
if (msgb_l3len(msg) < sizeof(*ccch)) {
LOGP(DL1C, LOGL_ERROR, "MSG too short Data Ind: %u\n",
msgb_l3len(msg));
msgb_free(msg);
return -1;
}
dl = (struct l1ctl_info_dl *) msg->l1h;
msg->l2h = dl->payload;
ccch = (struct l1ctl_data_ind *) msg->l2h;
gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
lchan = bts_ms->trx->slot[chan_ts].lchan[chan_ss];
if (!lchan) {
LOGP(DL1C, LOGL_ERROR, "Data IND for non existing lchan\n");
msgb_free(msg);
return -1;
}
LOGP(DL1C, LOGL_NOTICE, "RX: %s | %s(%.4u/%.2u/%.2u) %d dBm\n",
rsl_chan_nr_str(dl->chan_nr),
hexdump(ccch->data, sizeof(ccch->data)),
tm.t1, tm.t2, tm.t3, (int)dl->rx_level-110);
meas->last_fn = ntohl(dl->frame_nr);
meas->frames++;
meas->snr += dl->snr;
meas->berr += dl->num_biterr;
meas->rxlev += dl->rx_level;
if (dl->fire_crc >= 2) {
LOGP(DL1C, LOGL_NOTICE, "Dropping frame with %u bit errors\n",
dl->num_biterr);
msgb_free(msg);
return 0;
}
/* send CCCH data via GSMTAP */
gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, dl->link_id);
gsmtap_sendmsg(ntohs(dl->band_arfcn), chan_ts, gsmtap_chan_type, chan_ss,
tm.fn, dl->rx_level-110, dl->snr, ccch->data,
sizeof(ccch->data));
/* determine LAPDm entity based on SACCH or not */
if (dl->link_id & 0x40)
le = &lchan->l2_entity.lapdm_acch;
else
le = &lchan->l2_entity.lapdm_dcch;
/* make local stack copy of l1ctl_info_dl, as LAPDm will
* overwrite skb hdr */
memcpy(&dl_cpy, dl, sizeof(dl_cpy));
/* pull the L1 header from the msgb */
msgb_pull(msg, msg->l2h - (msg->l1h-sizeof(struct l1ctl_hdr)));
msg->l1h = NULL;
/* send it up into LAPDm */
l2_ph_data_ind(msg, le, &dl_cpy);
return 0;
}
/* Receive L1CTL_DATA_CONF (Data Confirm from L1) */
static int rx_ph_data_conf(struct osmocom_ms *ms, struct msgb *msg)
{
struct l1ctl_info_dl *dl;
struct lapdm_entity *le;
uint8_t chan_type, chan_ts, chan_ss;
struct osmobts_ms *bts_ms = container_of(ms, struct osmobts_ms, ms);
struct osmobts_lchan *lchan;
dl = (struct l1ctl_info_dl *) msg->l1h;
rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
lchan = bts_ms->trx->slot[chan_ts].lchan[chan_ss];
if (!lchan) {
LOGP(DL1C, LOGL_ERROR, "Data IND for non existing lchan\n");
msgb_free(msg);
return -1;
}
/* determine LAPDm entity based on SACCH or not */
if (dl->link_id & 0x40)
le = &lchan->l2_entity.lapdm_acch;
else
le = &lchan->l2_entity.lapdm_dcch;
/* send it up into LAPDm */
l2_ph_data_conf(msg, le);
return 0;
}
/* Transmit L1CTL_DATA_REQ */
int l1ctl_tx_data_req(struct osmocom_ms *ms, struct msgb *msg,
uint8_t chan_nr, uint8_t link_id)
{
struct l1ctl_hdr *l1h;
struct l1ctl_info_ul *l1i_ul;
uint8_t chan_type, chan_ts, chan_ss;
uint8_t gsmtap_chan_type;
if (msgb_l2len(msg) > 23) {
LOGP(DL1C, LOGL_ERROR, "L1 cannot handle message length "
"> 23 (%u)\n", msgb_l2len(msg));
msgb_free(msg);
return -EINVAL;
} else if (msgb_l2len(msg) < 23)
LOGP(DL1C, LOGL_ERROR, "L1 message length < 23 (%u) "
"doesn't seem right!\n", msgb_l2len(msg));
/* send copy via GSMTAP */
rsl_dec_chan_nr(chan_nr, &chan_type, &chan_ss, &chan_ts);
gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, link_id);
gsmtap_sendmsg(0|0x4000, chan_ts, gsmtap_chan_type, chan_ss,
0, 127, 255, msg->l2h, msgb_l2len(msg));
LOGP(DL1C, LOGL_NOTICE, "TX: %s | %s\n", rsl_chan_nr_str(chan_nr),
hexdump(msg->l2h, msgb_l2len(msg)));
/* prepend uplink info header */
l1i_ul = (struct l1ctl_info_ul *) msgb_push(msg, sizeof(*l1i_ul));
l1i_ul->chan_nr = chan_nr;
l1i_ul->link_id = link_id;
/* prepend l1 header */
msg->l1h = msgb_push(msg, sizeof(*l1h));
l1h = (struct l1ctl_hdr *) msg->l1h;
l1h->msg_type = L1CTL_DATA_REQ;
printf("todo: transcode message\n");
return osmo_send_l1(ms, msg);
}
/* Transmit L1CTL_RESET_REQ */
int l1ctl_tx_reset_req(struct osmocom_ms *ms, uint8_t type)
{
struct msgb *msg;
struct l1ctl_reset *res;
msg = osmo_l1_alloc(L1CTL_RESET_REQ);
if (!msg)
return -1;
LOGP(DL1C, LOGL_INFO, "Tx Reset Req (%u)\n", type);
res = (struct l1ctl_reset *) msgb_put(msg, sizeof(*res));
res->type = type;
return osmo_send_l1(ms, msg);
}
/* Receive L1CTL_RESET_IND */
static int rx_l1_reset(struct osmocom_ms *ms)
{
LOGP(DL1C, LOGL_INFO, "Layer1 Reset indication\n");
dispatch_signal(SS_L1CTL, S_L1CTL_RESET, ms);
return 0;
}
/* Receive incoming data from L1 using L1CTL format */
int l1ctl_recv(struct osmocom_ms *ms, struct msgb *msg)
{
int rc = 0;
struct l1ctl_hdr *l1h;
struct l1ctl_info_dl *dl;
if (msgb_l2len(msg) < sizeof(*dl)) {
LOGP(DL1C, LOGL_ERROR, "Short Layer2 message: %u\n",
msgb_l2len(msg));
msgb_free(msg);
return -1;
}
l1h = (struct l1ctl_hdr *) msg->l1h;
/* move the l1 header pointer to point _BEHIND_ l1ctl_hdr,
as the l1ctl header is of no interest to subsequent code */
msg->l1h = l1h->data;
switch (l1h->msg_type) {
case L1CTL_DATA_IND:
rc = rx_ph_data_ind(ms, msg);
break;
case L1CTL_DATA_CONF:
rc = rx_ph_data_conf(ms, msg);
break;
case L1CTL_RESET_IND:
case L1CTL_RESET_CONF:
rc = rx_l1_reset(ms);
msgb_free(msg);
break;
default:
LOGP(DL1C, LOGL_ERROR, "Unknown MSG: %u\n", l1h->msg_type);
msgb_free(msg);
break;
}
return rc;
}
int l1ctl_tx_param_req(struct osmocom_ms *ms, uint8_t ta, uint8_t tx_power)
{
return -ENOTSUP;
}
int l1ctl_tx_rach_req(struct osmocom_ms *ms, uint8_t ra, uint16_t offset,
uint8_t combined)
{
return -ENOTSUP;
}
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