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-rw-r--r--openbsc/src/chan_alloc.c256
1 files changed, 256 insertions, 0 deletions
diff --git a/openbsc/src/chan_alloc.c b/openbsc/src/chan_alloc.c
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index 000000000..77a4f57bc
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+++ b/openbsc/src/chan_alloc.c
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+/* GSM Channel allocation routines
+ *
+ * (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2008, 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ *
+ * 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 <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/chan_alloc.h>
+#include <openbsc/abis_nm.h>
+#include <openbsc/abis_rsl.h>
+#include <openbsc/debug.h>
+#include <openbsc/signal.h>
+
+static void auto_release_channel(void *_lchan);
+
+struct gsm_bts_trx_ts *ts_c0_alloc(struct gsm_bts *bts,
+ enum gsm_phys_chan_config pchan)
+{
+ struct gsm_bts_trx *trx = &bts->trx[0];
+ struct gsm_bts_trx_ts *ts = &trx->ts[0];
+
+ if (pchan != GSM_PCHAN_CCCH &&
+ pchan != GSM_PCHAN_CCCH_SDCCH4)
+ return NULL;
+
+ if (ts->pchan != GSM_PCHAN_NONE)
+ return NULL;
+
+ ts->pchan = pchan;
+
+ return ts;
+}
+
+static const enum abis_nm_chan_comb chcomb4pchan[] = {
+ [GSM_PCHAN_CCCH] = NM_CHANC_mainBCCH,
+ [GSM_PCHAN_CCCH_SDCCH4] = NM_CHANC_BCCCHComb,
+ [GSM_PCHAN_TCH_F] = NM_CHANC_TCHFull,
+ [GSM_PCHAN_TCH_H] = NM_CHANC_TCHHalf,
+ [GSM_PCHAN_SDCCH8_SACCH8C] = NM_CHANC_SDCCH,
+ /* FIXME: bounds check */
+};
+
+/* Allocate a logical channel (TS) */
+struct gsm_bts_trx_ts *ts_alloc(struct gsm_bts *bts,
+ enum gsm_phys_chan_config pchan)
+{
+ int i, j;
+ for (i = 0; i < bts->num_trx; i++) {
+ struct gsm_bts_trx *trx = &bts->trx[i];
+ int from, to;
+
+ /* the following constraints are pure policy,
+ * no requirement to put this restriction in place */
+ switch (pchan) {
+ case GSM_PCHAN_CCCH:
+ case GSM_PCHAN_CCCH_SDCCH4:
+ from = 0; to = 0;
+ break;
+ case GSM_PCHAN_SDCCH8_SACCH8C:
+ from = 1; to = 1;
+ break;
+ case GSM_PCHAN_TCH_F:
+ case GSM_PCHAN_TCH_H:
+ from = 2; to = 7;
+ break;
+ default:
+ return NULL;
+ }
+
+ for (j = from; j <= to; j++) {
+ struct gsm_bts_trx_ts *ts = &trx->ts[j];
+ if (ts->pchan == GSM_PCHAN_NONE) {
+ ts->pchan = pchan;
+ /* set channel attribute on OML */
+ abis_nm_set_channel_attr(ts, chcomb4pchan[pchan]);
+ return ts;
+ }
+ }
+ }
+ return NULL;
+}
+
+/* Free a physical channel (TS) */
+void ts_free(struct gsm_bts_trx_ts *ts)
+{
+ ts->pchan = GSM_PCHAN_NONE;
+}
+
+static const u_int8_t subslots_per_pchan[] = {
+ [GSM_PCHAN_NONE] = 0,
+ [GSM_PCHAN_CCCH] = 0,
+ [GSM_PCHAN_CCCH_SDCCH4] = 4,
+ [GSM_PCHAN_TCH_F] = 1,
+ [GSM_PCHAN_TCH_H] = 2,
+ [GSM_PCHAN_SDCCH8_SACCH8C] = 8.
+};
+
+static struct gsm_lchan *
+_lc_find(struct gsm_bts *bts, enum gsm_phys_chan_config pchan)
+{
+ struct gsm_bts_trx *trx;
+ struct gsm_bts_trx_ts *ts;
+ int i, j, ss;
+ for (i = 0; i < bts->num_trx; i++) {
+ trx = &bts->trx[i];
+ for (j = 0; j < 8; j++) {
+ ts = &trx->ts[j];
+ if (ts->pchan != pchan)
+ continue;
+ /* check if all sub-slots are allocated yet */
+ for (ss = 0; ss < subslots_per_pchan[pchan]; ss++) {
+ struct gsm_lchan *lc = &ts->lchan[ss];
+ if (lc->type == GSM_LCHAN_NONE)
+ return lc;
+ }
+ }
+ }
+ /* we cannot allocate more of these */
+ if (pchan == GSM_PCHAN_CCCH_SDCCH4)
+ return NULL;
+
+ /* if we've reached here, we need to allocate a new physical
+ * channel for the logical channel type requested */
+ ts = ts_alloc(bts, pchan);
+ if (!ts) {
+ /* no more radio resources */
+ return NULL;
+ }
+ return &ts->lchan[0];
+}
+
+/* Allocate a logical channel */
+struct gsm_lchan *lchan_alloc(struct gsm_bts *bts, enum gsm_chan_t type)
+{
+ struct gsm_lchan *lchan = NULL;
+
+ switch (type) {
+ case GSM_LCHAN_SDCCH:
+ lchan = _lc_find(bts, GSM_PCHAN_CCCH_SDCCH4);
+ if (lchan == NULL)
+ lchan = _lc_find(bts, GSM_PCHAN_SDCCH8_SACCH8C);
+ break;
+ case GSM_LCHAN_TCH_F:
+ lchan = _lc_find(bts, GSM_PCHAN_TCH_F);
+ break;
+ case GSM_LCHAN_TCH_H:
+ lchan =_lc_find(bts, GSM_PCHAN_TCH_H);
+ break;
+ default:
+ fprintf(stderr, "Unknown gsm_chan_t %u\n", type);
+ }
+
+ if (lchan) {
+ lchan->type = type;
+ lchan->use_count = 0;
+
+ /* Configure the time and start it so it will be closed */
+ lchan->release_timer.cb = auto_release_channel;
+ lchan->release_timer.data = lchan;
+ bsc_schedule_timer(&lchan->release_timer, LCHAN_RELEASE_TIMEOUT);
+ }
+
+ return lchan;
+}
+
+/* Free a logical channel */
+void lchan_free(struct gsm_lchan *lchan)
+{
+ lchan->type = GSM_LCHAN_NONE;
+ if (lchan->subscr) {
+ subscr_put(lchan->subscr);
+ lchan->subscr = 0;
+ }
+
+ /* We might kill an active channel... */
+ if (lchan->use_count != 0) {
+ dispatch_signal(SS_LCHAN, S_LCHAN_UNEXPECTED_RELEASE, lchan);
+ lchan->use_count = 0;
+ }
+
+ /* stop the timer */
+ bsc_del_timer(&lchan->release_timer);
+
+ /* FIXME: ts_free() the timeslot, if we're the last logical
+ * channel using it */
+}
+
+/* Consider releasing the channel now */
+int lchan_auto_release(struct gsm_lchan *lchan)
+{
+ if (lchan->use_count > 0) {
+ return 0;
+ }
+
+ /* Assume we have GSM04.08 running and send a release */
+ if (lchan->subscr) {
+ gsm48_send_rr_release(lchan);
+ }
+
+ /* spoofed? message */
+ if (lchan->use_count < 0) {
+ DEBUGP(DRLL, "Channel count is negative: %d\n", lchan->use_count);
+ }
+
+ DEBUGP(DRLL, "Recycling the channel with: %d (%x)\n", lchan->nr, lchan->nr);
+ rsl_chan_release(lchan);
+ return 1;
+}
+
+/* Auto release the channel when the use count is zero */
+static void auto_release_channel(void *_lchan)
+{
+ struct gsm_lchan *lchan = _lchan;
+
+ if (!lchan_auto_release(lchan))
+ bsc_schedule_timer(&lchan->release_timer, LCHAN_RELEASE_TIMEOUT);
+}
+
+struct gsm_lchan* lchan_find(struct gsm_bts *bts, struct gsm_subscriber *subscr) {
+ int trx, ts_no, lchan_no;
+
+ for (trx = 0; trx < bts->num_trx; ++trx) {
+ for (ts_no = 0; ts_no < 8; ++ts_no) {
+ for (lchan_no = 0; lchan_no < TS_MAX_LCHAN; ++lchan_no) {
+ struct gsm_lchan *lchan =
+ &bts->trx[trx].ts[ts_no].lchan[lchan_no];
+ if (subscr == lchan->subscr)
+ return lchan;
+ }
+ }
+ }
+
+ return NULL;
+}