src/host/layer23/src/l1ctl.c

   1 /* Layer1 control code, talking L1CTL protocol with L1 on the phone */
   2
   3 /* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
   4  * (C) 2010 by Harald Welte <laforge@gnumonks.org>
   5  *
   6  * All Rights Reserved
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdint.h>
  26 #include <string.h>
  27 #include <errno.h>
  28
  29 #include <arpa/inet.h>
  30
  31 #include <l1a_l23_interface.h>
  32
  33 #include <osmocore/signal.h>
  34 #include <osmocore/logging.h>
  35 #include <osmocore/timer.h>
  36 #include <osmocore/msgb.h>
  37 #include <osmocore/tlv.h>
  38 #include <osmocore/gsm_utils.h>
  39 #include <osmocore/protocol/gsm_04_08.h>
  40 #include <osmocore/protocol/gsm_08_58.h>
  41 #include <osmocore/rsl.h>
  42
  43 #include <osmocom/l1ctl.h>
  44 #include <osmocom/osmocom_data.h>
  45 #include <osmocom/l1l2_interface.h>
  46 #include <osmocom/lapdm.h>
  47 #include <osmocom/logging.h>
  48 #include <osmocom/gsmtap_util.h>
  49
  50 static struct msgb *osmo_l1_alloc(uint8_t msg_type)
  51 {
  52         struct l1ctl_hdr *l1h;
  53         struct msgb *msg = msgb_alloc_headroom(256, 4, "osmo_l1");
  54
  55         if (!msg) {
  56                 LOGP(DL1C, LOGL_ERROR, "Failed to allocate memory.\n");
  57                 return NULL;
  58         }
  59
  60         msg->l1h = msgb_put(msg, sizeof(*l1h));
  61         l1h = (struct l1ctl_hdr *) msg->l1h;
  62         l1h->msg_type = msg_type;
  63
  64         return msg;
  65 }
  66
  67
  68 static int osmo_make_band_arfcn(struct osmocom_ms *ms, uint16_t arfcn)
  69 {
  70         /* TODO: Include the band */
  71         return arfcn;
  72 }
  73
  74 static int rx_l1_fbsb_resp(struct osmocom_ms *ms, struct msgb *msg)
  75 {
  76         struct l1ctl_info_dl *dl;
  77         struct l1ctl_fbsb_resp *sb;
  78         struct gsm_time tm;
  79
  80         if (msgb_l3len(msg) < sizeof(*dl) + sizeof(*sb)) {
  81                 LOGP(DL1C, LOGL_ERROR, "FBSB RESP: MSG too short %u\n",
  82                         msgb_l3len(msg));
  83                 return -1;
  84         }
  85
  86         dl = (struct l1ctl_info_dl *) msg->l1h;
  87         sb = (struct l1ctl_fbsb_resp *) dl->payload;
  88
  89         printf("snr=%04x, arfcn=%u result=%u\n", dl->snr, ntohs(dl->band_arfcn),
  90                 sb->result);
  91
  92         if (sb->result != 0) {
  93                 LOGP(DL1C, LOGL_ERROR, "FBSB RESP: result=%u\n", sb->result);
  94                 dispatch_signal(SS_L1CTL, S_L1CTL_FBSB_ERR, ms);
  95                 return 0;
  96         }
  97
  98         gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
  99         DEBUGP(DL1C, "SCH: SNR: %u TDMA: (%.4u/%.2u/%.2u) bsic: %d\n",
 100                 dl->snr, tm.t1, tm.t2, tm.t3, sb->bsic);
 101         dispatch_signal(SS_L1CTL, S_L1CTL_FBSB_RESP, ms);
 102
 103         return 0;
 104 }
 105
 106 char *chan_nr2string(uint8_t chan_nr)
 107 {
 108         static char str[20];
 109         uint8_t cbits = chan_nr >> 3;
 110
 111         str[0] = '\0';
 112
 113         if (cbits == 0x01)
 114                 sprintf(str, "TCH/F");
 115         else if ((cbits & 0x1e) == 0x02)
 116                 sprintf(str, "TCH/H(%u)", cbits & 0x01);
 117         else if ((cbits & 0x1c) == 0x04)
 118                 sprintf(str, "SDCCH/4(%u)", cbits & 0x03);
 119         else if ((cbits & 0x18) == 0x08)
 120                 sprintf(str, "SDCCH/8(%u)", cbits & 0x07);
 121         else if (cbits == 0x10)
 122                 sprintf(str, "BCCH");
 123         else if (cbits == 0x11)
 124                 sprintf(str, "RACH");
 125         else if (cbits == 0x12)
 126                 sprintf(str, "PCH/AGCH");
 127         else
 128                 sprintf(str, "UNKNOWN");
 129
 130         return str;
 131 }
 132
 133 /* Receive L1CTL_DATA_IND (Data Indication from L1) */
 134 static int rx_ph_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 135 {
 136         struct l1ctl_info_dl *dl, dl_cpy;
 137         struct l1ctl_data_ind *ccch;
 138         struct lapdm_entity *le;
 139         uint8_t chan_type, chan_ts, chan_ss;
 140         uint8_t gsmtap_chan_type;
 141         struct gsm_time tm;
 142
 143         if (msgb_l3len(msg) < sizeof(*ccch)) {
 144                 LOGP(DL1C, LOGL_ERROR, "MSG too short Data Ind: %u\n",
 145                         msgb_l3len(msg));
 146                 msgb_free(msg);
 147                 return -1;
 148         }
 149
 150         dl = (struct l1ctl_info_dl *) msg->l1h;
 151         msg->l2h = dl->payload;
 152         ccch = (struct l1ctl_data_ind *) msg->l2h;
 153
 154         gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
 155         rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
 156         DEBUGP(DL1C, "%s (%.4u/%.2u/%.2u) %s\n",
 157                 chan_nr2string(dl->chan_nr), tm.t1, tm.t2, tm.t3,
 158                 hexdump(ccch->data, sizeof(ccch->data)));
 159
 160         if (dl->num_biterr) {
 161                 LOGP(DL1C, LOGL_NOTICE, "Dropping frame with %u bit errors\n",
 162                         dl->num_biterr);
 163                 return 0;
 164         }
 165
 166         /* send CCCH data via GSMTAP */
 167         gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, dl->link_id);
 168         gsmtap_sendmsg(ntohs(dl->band_arfcn), chan_ts, gsmtap_chan_type, chan_ss,
 169                         tm.fn, dl->rx_level-110, dl->snr, ccch->data,
 170                         sizeof(ccch->data));
 171
 172         /* determine LAPDm entity based on SACCH or not */
 173         if (dl->link_id & 0x40)
 174                 le = &ms->l2_entity.lapdm_acch;
 175         else
 176                 le = &ms->l2_entity.lapdm_dcch;
 177         /* make local stack copy of l1ctl_info_dl, as LAPDm will
 178          * overwrite skb hdr */
 179         memcpy(&dl_cpy, dl, sizeof(dl_cpy));
 180
 181         /* pull the L1 header from the msgb */
 182         msgb_pull(msg, msg->l2h - (msg->l1h-sizeof(struct l1ctl_hdr)));
 183         msg->l1h = NULL;
 184
 185         /* send it up into LAPDm */
 186         l2_ph_data_ind(msg, le, &dl_cpy);
 187
 188         return 0;
 189 }
 190
 191 /* Transmit L1CTL_DATA_REQ */
 192 int tx_ph_data_req(struct osmocom_ms *ms, struct msgb *msg,
 193                    uint8_t chan_nr, uint8_t link_id)
 194 {
 195         struct l1ctl_hdr *l1h;
 196         struct l1ctl_info_ul *l1i_ul;
 197         uint8_t chan_type, chan_ts, chan_ss;
 198         uint8_t gsmtap_chan_type;
 199
 200         DEBUGP(DL1C, "(%s)\n", hexdump(msg->l2h, msgb_l2len(msg)));
 201
 202         if (msgb_l2len(msg) > 23) {
 203                 LOGP(DL1C, LOGL_ERROR, "L1 cannot handle message length "
 204                         "> 23 (%u)\n", msgb_l2len(msg));
 205                 msgb_free(msg);
 206                 return -EINVAL;
 207         } else if (msgb_l2len(msg) < 23)
 208                 LOGP(DL1C, LOGL_ERROR, "L1 message length < 23 (%u) "
 209                         "doesn't seem right!\n", msgb_l2len(msg));
 210
 211         /* send copy via GSMTAP */
 212         rsl_dec_chan_nr(chan_nr, &chan_type, &chan_ss, &chan_ts);
 213         gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, link_id);
 214         gsmtap_sendmsg(0|0x4000, chan_ts, gsmtap_chan_type, chan_ss,
 215                         0, 127, 255, msg->l2h, msgb_l2len(msg));
 216
 217         /* prepend uplink info header */
 218         l1i_ul = (struct l1ctl_info_ul *) msgb_push(msg, sizeof(*l1i_ul));
 219
 220         l1i_ul->chan_nr = chan_nr;
 221         l1i_ul->link_id = link_id;
 222
 223         /* FIXME: where to get this from? */
 224         l1i_ul->tx_power = 0;
 225
 226         /* prepend l1 header */
 227         msg->l1h = msgb_push(msg, sizeof(*l1h));
 228         l1h = (struct l1ctl_hdr *) msg->l1h;
 229         l1h->msg_type = L1CTL_DATA_REQ;
 230
 231         return osmo_send_l1(ms, msg);
 232 }
 233
 234 /* Transmit FBSB_REQ */
 235 int l1ctl_tx_fbsb_req(struct osmocom_ms *ms, uint16_t arfcn,
 236                       uint8_t flags, uint16_t timeout, uint8_t sync_info_idx)
 237 {
 238         struct msgb *msg;
 239         struct l1ctl_fbsb_req *req;
 240
 241         msg = osmo_l1_alloc(L1CTL_FBSB_REQ);
 242         if (!msg)
 243                 return -1;
 244
 245         req = (struct l1ctl_fbsb_req *) msgb_put(msg, sizeof(*req));
 246         req->band_arfcn = htons(osmo_make_band_arfcn(ms, arfcn));
 247         req->timeout = htons(timeout);
 248         /* Threshold when to consider FB_MODE1: 4kHz - 1kHz */
 249         req->freq_err_thresh1 = htons(4000 - 1000);
 250         /* Threshold when to consider SCH: 1kHz - 200Hz */
 251         req->freq_err_thresh2 = htons(1000 - 200);
 252         /* not used yet! */
 253         req->num_freqerr_avg = 3;
 254         req->flags = flags;
 255         req->sync_info_idx = sync_info_idx;
 256
 257         return osmo_send_l1(ms, msg);
 258 }
 259
 260 /* Transmit L1CTL_RACH_REQ */
 261 int tx_ph_rach_req(struct osmocom_ms *ms)
 262 {
 263         struct msgb *msg;
 264         struct l1ctl_info_ul *ul;
 265         struct l1ctl_rach_req *req;
 266         static uint8_t i = 0;
 267
 268         msg = osmo_l1_alloc(L1CTL_RACH_REQ);
 269         if (!msg)
 270                 return -1;
 271
 272         DEBUGP(DL1C, "RACH Req.\n");
 273         ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
 274         req = (struct l1ctl_rach_req *) msgb_put(msg, sizeof(*req));
 275         req->ra = i++;
 276
 277         return osmo_send_l1(ms, msg);
 278 }
 279
 280 /* Transmit L1CTL_DM_EST_REQ */
 281 int tx_ph_dm_est_req(struct osmocom_ms *ms, uint16_t band_arfcn, uint8_t chan_nr)
 282 {
 283         struct msgb *msg;
 284         struct l1ctl_info_ul *ul;
 285         struct l1ctl_dm_est_req *req;
 286
 287         msg = osmo_l1_alloc(L1CTL_DM_EST_REQ);
 288         if (!msg)
 289                 return -1;
 290
 291         DEBUGP(DL1C, "Tx Dedic.Mode Est Req (arfcn=%u, chan_nr=0x%02x)\n",
 292                 band_arfcn, chan_nr);
 293         ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
 294         ul->chan_nr = chan_nr;
 295         ul->link_id = 0;
 296         ul->tx_power = 0; /* FIXME: initial TX power */
 297         req = (struct l1ctl_dm_est_req *) msgb_put(msg, sizeof(*req));
 298         req->band_arfcn = htons(band_arfcn);
 299
 300         return osmo_send_l1(ms, msg);
 301 }
 302
 303 int l1ctl_tx_echo_req(struct osmocom_ms *ms, unsigned int len)
 304 {
 305         struct msgb *msg;
 306         uint8_t *data;
 307         unsigned int i;
 308
 309         msg = osmo_l1_alloc(L1CTL_ECHO_REQ);
 310         if (!msg)
 311                 return -1;
 312
 313         data = msgb_put(msg, len);
 314         for (i = 0; i < len; i++)
 315                 data[i] = i % 8;
 316
 317         return osmo_send_l1(ms, msg);
 318 }
 319
 320 /* Transmit L1CTL_PM_REQ */
 321 int l1ctl_tx_pm_req_range(struct osmocom_ms *ms, uint16_t arfcn_from,
 322                           uint16_t arfcn_to)
 323 {
 324         struct msgb *msg;
 325         struct l1ctl_pm_req *pm;
 326
 327         msg = osmo_l1_alloc(L1CTL_PM_REQ);
 328         if (!msg)
 329                 return -1;
 330
 331         printf("Tx PM Req (%u-%u)\n", arfcn_from, arfcn_to);
 332         pm = (struct l1ctl_pm_req *) msgb_put(msg, sizeof(*pm));
 333         pm->type = 1;
 334         pm->range.band_arfcn_from = htons(arfcn_from);
 335         pm->range.band_arfcn_to = htons(arfcn_to);
 336
 337         return osmo_send_l1(ms, msg);
 338 }
 339
 340 /* Receive L1CTL_RESET_IND */
 341 static int rx_l1_reset(struct osmocom_ms *ms)
 342 {
 343         printf("Layer1 Reset.\n");
 344         dispatch_signal(SS_L1CTL, S_L1CTL_RESET, ms);
 345
 346         return 0;
 347 }
 348
 349 /* Receive L1CTL_PM_RESP */
 350 static int rx_l1_pm_resp(struct osmocom_ms *ms, struct msgb *msg)
 351 {
 352         struct l1ctl_pm_resp *pmr;
 353
 354         for (pmr = (struct l1ctl_pm_resp *) msg->l1h;
 355              (uint8_t *) pmr < msg->tail; pmr++) {
 356                 struct osmobb_meas_res mr;
 357                 DEBUGP(DL1C, "PM MEAS: ARFCN: %4u RxLev: %3d %3d\n",
 358                         ntohs(pmr->band_arfcn), pmr->pm[0], pmr->pm[1]);
 359                 mr.band_arfcn = ntohs(pmr->band_arfcn);
 360                 mr.rx_lev = (pmr->pm[0] + pmr->pm[1]) / 2;
 361                 mr.ms = ms;
 362                 dispatch_signal(SS_L1CTL, S_L1CTL_PM_RES, &mr);
 363         }
 364         return 0;
 365 }
 366
 367 /* Receive incoming data from L1 using L1CTL format */
 368 int l1ctl_recv(struct osmocom_ms *ms, struct msgb *msg)
 369 {
 370         int rc = 0;
 371         struct l1ctl_hdr *l1h;
 372         struct l1ctl_info_dl *dl;
 373
 374         if (msgb_l2len(msg) < sizeof(*dl)) {
 375                 LOGP(DL1C, LOGL_ERROR, "Short Layer2 message: %u\n",
 376                         msgb_l2len(msg));
 377                 msgb_free(msg);
 378                 return -1;
 379         }
 380
 381         l1h = (struct l1ctl_hdr *) msg->l1h;
 382
 383         /* move the l1 header pointer to point _BEHIND_ l1ctl_hdr,
 384            as the l1ctl header is of no interest to subsequent code */
 385         msg->l1h = l1h->data;
 386
 387         switch (l1h->msg_type) {
 388         case L1CTL_FBSB_RESP:
 389                 rc = rx_l1_fbsb_resp(ms, msg);
 390                 msgb_free(msg);
 391                 break;
 392         case L1CTL_DATA_IND:
 393                 rc = rx_ph_data_ind(ms, msg);
 394                 break;
 395         case L1CTL_RESET_IND:
 396                 rc = rx_l1_reset(ms);
 397                 msgb_free(msg);
 398                 break;
 399         case L1CTL_PM_RESP:
 400                 rc = rx_l1_pm_resp(ms, msg);
 401                 msgb_free(msg);
 402                 if (l1h->flags & L1CTL_F_DONE)
 403                         dispatch_signal(SS_L1CTL, S_L1CTL_PM_DONE, ms);
 404                 break;
 405         default:
 406                 fprintf(stderr, "Unknown MSG: %u\n", l1h->msg_type);
 407                 msgb_free(msg);
 408                 break;
 409         }
 410
 411         return rc;
 412 }