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_conf(struct osmocom_ms *ms, struct msgb *msg)
  75 {
  76         struct l1ctl_info_dl *dl;
  77         struct l1ctl_fbsb_conf *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_conf *) 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 static int rx_l1_rach_conf(struct osmocom_ms *ms, struct msgb *msg)
 107 {
 108         struct l1ctl_info_dl *dl;
 109         struct osmobb_rach_conf rc;
 110
 111         if (msgb_l3len(msg) < sizeof(*dl)) {
 112                 LOGP(DL1C, LOGL_ERROR, "RACH CONF: MSG too short %u\n",
 113                         msgb_l3len(msg));
 114                 return -1;
 115         }
 116
 117         dl = (struct l1ctl_info_dl *) msg->l1h;
 118
 119         printf("RACH CONF: arfcn=%u fn=%u\n", dl->snr, ntohl(dl->frame_nr));
 120
 121         rc.fn = htonl(dl->frame_nr);
 122         rc.ms = ms;
 123         dispatch_signal(SS_L1CTL, S_L1CTL_RACH_CONF, &rc);
 124
 125         return 0;
 126 }
 127
 128 char *chan_nr2string(uint8_t chan_nr)
 129 {
 130         static char str[20];
 131         uint8_t cbits = chan_nr >> 3;
 132
 133         str[0] = '\0';
 134
 135         if (cbits == 0x01)
 136                 sprintf(str, "TCH/F");
 137         else if ((cbits & 0x1e) == 0x02)
 138                 sprintf(str, "TCH/H(%u)", cbits & 0x01);
 139         else if ((cbits & 0x1c) == 0x04)
 140                 sprintf(str, "SDCCH/4(%u)", cbits & 0x03);
 141         else if ((cbits & 0x18) == 0x08)
 142                 sprintf(str, "SDCCH/8(%u)", cbits & 0x07);
 143         else if (cbits == 0x10)
 144                 sprintf(str, "BCCH");
 145         else if (cbits == 0x11)
 146                 sprintf(str, "RACH");
 147         else if (cbits == 0x12)
 148                 sprintf(str, "PCH/AGCH");
 149         else
 150                 sprintf(str, "UNKNOWN");
 151
 152         return str;
 153 }
 154
 155 /* Receive L1CTL_DATA_IND (Data Indication from L1) */
 156 static int rx_ph_data_ind(struct osmocom_ms *ms, struct msgb *msg)
 157 {
 158         struct l1ctl_info_dl *dl, dl_cpy;
 159         struct l1ctl_data_ind *ccch;
 160         struct lapdm_entity *le;
 161         uint8_t chan_type, chan_ts, chan_ss;
 162         uint8_t gsmtap_chan_type;
 163         struct gsm_time tm;
 164
 165         if (msgb_l3len(msg) < sizeof(*ccch)) {
 166                 LOGP(DL1C, LOGL_ERROR, "MSG too short Data Ind: %u\n",
 167                         msgb_l3len(msg));
 168                 msgb_free(msg);
 169                 return -1;
 170         }
 171
 172         dl = (struct l1ctl_info_dl *) msg->l1h;
 173         msg->l2h = dl->payload;
 174         ccch = (struct l1ctl_data_ind *) msg->l2h;
 175
 176         gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
 177         rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
 178         DEBUGP(DL1C, "%s (%.4u/%.2u/%.2u) %s\n",
 179                 chan_nr2string(dl->chan_nr), tm.t1, tm.t2, tm.t3,
 180                 hexdump(ccch->data, sizeof(ccch->data)));
 181
 182         if (dl->num_biterr) {
 183                 LOGP(DL1C, LOGL_NOTICE, "Dropping frame with %u bit errors\n",
 184                         dl->num_biterr);
 185                 return 0;
 186         }
 187
 188         /* send CCCH data via GSMTAP */
 189         gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, dl->link_id);
 190         gsmtap_sendmsg(ntohs(dl->band_arfcn), chan_ts, gsmtap_chan_type, chan_ss,
 191                         tm.fn, dl->rx_level-110, dl->snr, ccch->data,
 192                         sizeof(ccch->data));
 193
 194         /* determine LAPDm entity based on SACCH or not */
 195         if (dl->link_id & 0x40)
 196                 le = &ms->l2_entity.lapdm_acch;
 197         else
 198                 le = &ms->l2_entity.lapdm_dcch;
 199         /* make local stack copy of l1ctl_info_dl, as LAPDm will
 200          * overwrite skb hdr */
 201         memcpy(&dl_cpy, dl, sizeof(dl_cpy));
 202
 203         /* pull the L1 header from the msgb */
 204         msgb_pull(msg, msg->l2h - (msg->l1h-sizeof(struct l1ctl_hdr)));
 205         msg->l1h = NULL;
 206
 207         /* send it up into LAPDm */
 208         l2_ph_data_ind(msg, le, &dl_cpy);
 209
 210         return 0;
 211 }
 212
 213 /* Transmit L1CTL_DATA_REQ */
 214 int tx_ph_data_req(struct osmocom_ms *ms, struct msgb *msg,
 215                    uint8_t chan_nr, uint8_t link_id)
 216 {
 217         struct l1ctl_hdr *l1h;
 218         struct l1ctl_info_ul *l1i_ul;
 219         uint8_t chan_type, chan_ts, chan_ss;
 220         uint8_t gsmtap_chan_type;
 221
 222         DEBUGP(DL1C, "(%s)\n", hexdump(msg->l2h, msgb_l2len(msg)));
 223
 224         if (msgb_l2len(msg) > 23) {
 225                 LOGP(DL1C, LOGL_ERROR, "L1 cannot handle message length "
 226                         "> 23 (%u)\n", msgb_l2len(msg));
 227                 msgb_free(msg);
 228                 return -EINVAL;
 229         } else if (msgb_l2len(msg) < 23)
 230                 LOGP(DL1C, LOGL_ERROR, "L1 message length < 23 (%u) "
 231                         "doesn't seem right!\n", msgb_l2len(msg));
 232
 233         /* send copy via GSMTAP */
 234         rsl_dec_chan_nr(chan_nr, &chan_type, &chan_ss, &chan_ts);
 235         gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, link_id);
 236         gsmtap_sendmsg(0|0x4000, chan_ts, gsmtap_chan_type, chan_ss,
 237                         0, 127, 255, msg->l2h, msgb_l2len(msg));
 238
 239         /* prepend uplink info header */
 240         l1i_ul = (struct l1ctl_info_ul *) msgb_push(msg, sizeof(*l1i_ul));
 241
 242         l1i_ul->chan_nr = chan_nr;
 243         l1i_ul->link_id = link_id;
 244
 245         /* FIXME: where to get this from? */
 246         l1i_ul->tx_power = 0;
 247
 248         /* prepend l1 header */
 249         msg->l1h = msgb_push(msg, sizeof(*l1h));
 250         l1h = (struct l1ctl_hdr *) msg->l1h;
 251         l1h->msg_type = L1CTL_DATA_REQ;
 252
 253         return osmo_send_l1(ms, msg);
 254 }
 255
 256 /* Transmit FBSB_REQ */
 257 int l1ctl_tx_fbsb_req(struct osmocom_ms *ms, uint16_t arfcn,
 258                       uint8_t flags, uint16_t timeout, uint8_t sync_info_idx,
 259                       uint8_t ccch_mode)
 260 {
 261         struct msgb *msg;
 262         struct l1ctl_fbsb_req *req;
 263
 264         msg = osmo_l1_alloc(L1CTL_FBSB_REQ);
 265         if (!msg)
 266                 return -1;
 267
 268         req = (struct l1ctl_fbsb_req *) msgb_put(msg, sizeof(*req));
 269         req->band_arfcn = htons(osmo_make_band_arfcn(ms, arfcn));
 270         req->timeout = htons(timeout);
 271         /* Threshold when to consider FB_MODE1: 4kHz - 1kHz */
 272         req->freq_err_thresh1 = htons(4000 - 1000);
 273         /* Threshold when to consider SCH: 1kHz - 200Hz */
 274         req->freq_err_thresh2 = htons(1000 - 200);
 275         /* not used yet! */
 276         req->num_freqerr_avg = 3;
 277         req->flags = flags;
 278         req->sync_info_idx = sync_info_idx;
 279         req->ccch_mode = ccch_mode;
 280
 281         return osmo_send_l1(ms, msg);
 282 }
 283
 284 /* Transmit L1CTL_CCCH_MODE_REQ */
 285 int l1ctl_tx_ccch_mode_req(struct osmocom_ms *ms, uint8_t ccch_mode)
 286 {
 287         struct msgb *msg;
 288         struct l1ctl_ccch_mode_req *req;
 289
 290         msg = osmo_l1_alloc(L1CTL_CCCH_MODE_REQ);
 291         if (!msg)
 292                 return -1;
 293
 294         req = (struct l1ctl_ccch_mode_req *) msgb_put(msg, sizeof(*req));
 295         req->ccch_mode = ccch_mode;
 296
 297         return osmo_send_l1(ms, msg);
 298 }
 299
 300 /* Transmit L1CTL_RACH_REQ */
 301 int tx_ph_rach_req(struct osmocom_ms *ms)
 302 {
 303         struct msgb *msg;
 304         struct l1ctl_info_ul *ul;
 305         struct l1ctl_rach_req *req;
 306         static uint8_t i = 0;
 307
 308         msg = osmo_l1_alloc(L1CTL_RACH_REQ);
 309         if (!msg)
 310                 return -1;
 311
 312         DEBUGP(DL1C, "RACH Req.\n");
 313         ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
 314         req = (struct l1ctl_rach_req *) msgb_put(msg, sizeof(*req));
 315         req->ra = i++;
 316
 317         return osmo_send_l1(ms, msg);
 318 }
 319
 320 /* Transmit L1CTL_DM_EST_REQ */
 321 int tx_ph_dm_est_req(struct osmocom_ms *ms, uint16_t band_arfcn, uint8_t chan_nr,
 322                      uint8_t tsc)
 323 {
 324         struct msgb *msg;
 325         struct l1ctl_info_ul *ul;
 326         struct l1ctl_dm_est_req *req;
 327
 328         msg = osmo_l1_alloc(L1CTL_DM_EST_REQ);
 329         if (!msg)
 330                 return -1;
 331
 332         DEBUGP(DL1C, "Tx Dedic.Mode Est Req (arfcn=%u, chan_nr=0x%02x)\n",
 333                 band_arfcn, chan_nr);
 334
 335         ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
 336         ul->chan_nr = chan_nr;
 337         ul->link_id = 0;
 338         ul->tx_power = 0; /* FIXME: initial TX power */
 339
 340         req = (struct l1ctl_dm_est_req *) msgb_put(msg, sizeof(*req));
 341         req->tsc = tsc;
 342         req->h = 0;
 343         req->h0.band_arfcn = htons(band_arfcn);
 344
 345         return osmo_send_l1(ms, msg);
 346 }
 347
 348 int l1ctl_tx_echo_req(struct osmocom_ms *ms, unsigned int len)
 349 {
 350         struct msgb *msg;
 351         uint8_t *data;
 352         unsigned int i;
 353
 354         msg = osmo_l1_alloc(L1CTL_ECHO_REQ);
 355         if (!msg)
 356                 return -1;
 357
 358         data = msgb_put(msg, len);
 359         for (i = 0; i < len; i++)
 360                 data[i] = i % 8;
 361
 362         return osmo_send_l1(ms, msg);
 363 }
 364
 365 /* Transmit L1CTL_PM_REQ */
 366 int l1ctl_tx_pm_req_range(struct osmocom_ms *ms, uint16_t arfcn_from,
 367                           uint16_t arfcn_to)
 368 {
 369         struct msgb *msg;
 370         struct l1ctl_pm_req *pm;
 371
 372         msg = osmo_l1_alloc(L1CTL_PM_REQ);
 373         if (!msg)
 374                 return -1;
 375
 376         printf("Tx PM Req (%u-%u)\n", arfcn_from, arfcn_to);
 377         pm = (struct l1ctl_pm_req *) msgb_put(msg, sizeof(*pm));
 378         pm->type = 1;
 379         pm->range.band_arfcn_from = htons(arfcn_from);
 380         pm->range.band_arfcn_to = htons(arfcn_to);
 381
 382         return osmo_send_l1(ms, msg);
 383 }
 384
 385 /* Receive L1CTL_RESET_IND */
 386 static int rx_l1_reset(struct osmocom_ms *ms)
 387 {
 388         printf("Layer1 Reset.\n");
 389         dispatch_signal(SS_L1CTL, S_L1CTL_RESET, ms);
 390
 391         return 0;
 392 }
 393
 394 /* Receive L1CTL_PM_CONF */
 395 static int rx_l1_pm_conf(struct osmocom_ms *ms, struct msgb *msg)
 396 {
 397         struct l1ctl_pm_conf *pmr;
 398
 399         for (pmr = (struct l1ctl_pm_conf *) msg->l1h;
 400              (uint8_t *) pmr < msg->tail; pmr++) {
 401                 struct osmobb_meas_res mr;
 402                 DEBUGP(DL1C, "PM MEAS: ARFCN: %4u RxLev: %3d %3d\n",
 403                         ntohs(pmr->band_arfcn), pmr->pm[0], pmr->pm[1]);
 404                 mr.band_arfcn = ntohs(pmr->band_arfcn);
 405                 mr.rx_lev = (pmr->pm[0] + pmr->pm[1]) / 2;
 406                 mr.ms = ms;
 407                 dispatch_signal(SS_L1CTL, S_L1CTL_PM_RES, &mr);
 408         }
 409         return 0;
 410 }
 411
 412 /* Receive incoming data from L1 using L1CTL format */
 413 int l1ctl_recv(struct osmocom_ms *ms, struct msgb *msg)
 414 {
 415         int rc = 0;
 416         struct l1ctl_hdr *l1h;
 417         struct l1ctl_info_dl *dl;
 418
 419         if (msgb_l2len(msg) < sizeof(*dl)) {
 420                 LOGP(DL1C, LOGL_ERROR, "Short Layer2 message: %u\n",
 421                         msgb_l2len(msg));
 422                 msgb_free(msg);
 423                 return -1;
 424         }
 425
 426         l1h = (struct l1ctl_hdr *) msg->l1h;
 427
 428         /* move the l1 header pointer to point _BEHIND_ l1ctl_hdr,
 429            as the l1ctl header is of no interest to subsequent code */
 430         msg->l1h = l1h->data;
 431
 432         switch (l1h->msg_type) {
 433         case L1CTL_FBSB_CONF:
 434                 rc = rx_l1_fbsb_conf(ms, msg);
 435                 msgb_free(msg);
 436                 break;
 437         case L1CTL_DATA_IND:
 438                 rc = rx_ph_data_ind(ms, msg);
 439                 break;
 440         case L1CTL_RESET_IND:
 441                 rc = rx_l1_reset(ms);
 442                 msgb_free(msg);
 443                 break;
 444         case L1CTL_PM_CONF:
 445                 rc = rx_l1_pm_conf(ms, msg);
 446                 msgb_free(msg);
 447                 if (l1h->flags & L1CTL_F_DONE)
 448                         dispatch_signal(SS_L1CTL, S_L1CTL_PM_DONE, ms);
 449                 break;
 450         case L1CTL_RESET_CONF:
 451                 LOGP(DL1C, LOGL_NOTICE, "L1CTL_RESET_CONF\n");
 452                 msgb_free(msg);
 453                 break;
 454         case L1CTL_RACH_CONF:
 455                 LOGP(DL1C, LOGL_NOTICE, "L1CTL_RACH_CONF\n");
 456                 rc = rx_l1_rach_conf(ms, msg);
 457                 msgb_free(msg);
 458                 break;
 459         case L1CTL_DATA_CONF:
 460                 LOGP(DL1C, LOGL_NOTICE, "L1CTL_DATA_CONF\n");
 461                 msgb_free(msg);
 462                 break;
 463         default:
 464                 fprintf(stderr, "Unknown MSG: %u\n", l1h->msg_type);
 465                 msgb_free(msg);
 466                 break;
 467         }
 468
 469         return rc;
 470 }