ASCI: Add simple implementation of Group Call Register
This is a built-in data structure to store and handle voice group calls.
The GCR will be used by VGCS/VBS call control.
(Chg-Id: I9947403fde8212b66758104443c60aaacc8b1e7b)
The GCR will be used by VTY code.
(Chg-Id: I5bd034a62fc8b483f550d29103c2f7587198f590)
Change-Id: Ia74a4a865f943c5fb388cd28f9406005c92e663e
Related: OS#4854
diff --git a/src/libmsc/asci_gcr.c b/src/libmsc/asci_gcr.c
new file mode 100644
index 0000000..2208151
--- /dev/null
+++ b/src/libmsc/asci_gcr.c
@@ -0,0 +1,175 @@
+/* Group Call Register (GCR) */
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * Author: Andreas Eversberg
+ *
+ * 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 <osmocom/msc/gsm_data.h>
+#include <osmocom/msc/transaction.h>
+
+#include <osmocom/msc/asci_gcr.h>
+
+#define GCR_DEFAULT_TIMEOUT 60
+
+static uint32_t pow10[9] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 };
+
+/* Add cell to BSS list. */
+struct gcr_cell *gcr_add_cell(struct gcr_bss *bss, uint16_t cell_id)
+{
+ struct gcr_cell *c;
+
+ c = talloc_zero(bss, struct gcr_cell);
+ if (!c)
+ return NULL;
+ c->cell_id = cell_id;
+ llist_add_tail(&c->list, &bss->cell_list);
+
+ return c;
+}
+
+/* Find cell entry in BSS list. */
+struct gcr_cell *gcr_find_cell(struct gcr_bss *bss, uint16_t cell_id)
+{
+ struct gcr_cell *c;
+
+ llist_for_each_entry(c, &bss->cell_list, list) {
+ if (c->cell_id == cell_id)
+ return c;
+ }
+
+ return NULL;
+}
+
+/* Remove cell entry from BSS list. */
+void gcr_rm_cell(struct gcr_bss *bss, uint16_t cell_id)
+{
+ struct gcr_cell *c = gcr_find_cell(bss, cell_id);
+
+ if (c) {
+ llist_del(&c->list);
+ talloc_free(c);
+ }
+}
+
+/* Add BSS to GCR list. */
+struct gcr_bss *gcr_add_bss(struct gcr *gcr, int pc)
+{
+ struct gcr_bss *b;
+
+ b = talloc_zero(gcr, struct gcr_bss);
+ if (!b)
+ return NULL;
+ INIT_LLIST_HEAD(&b->cell_list);
+ b->pc = pc;
+ llist_add_tail(&b->list, &gcr->bss_list);
+
+ return b;
+}
+
+/* Find BSS entry in GCR list. */
+struct gcr_bss *gcr_find_bss(struct gcr *gcr, int pc)
+{
+ struct gcr_bss *b;
+
+ llist_for_each_entry(b, &gcr->bss_list, list) {
+ if (b->pc == pc)
+ return b;
+ }
+
+ return NULL;
+}
+
+/* Remove BSS entry from GCR list. */
+void gcr_rm_bss(struct gcr *gcr, int pc)
+{
+ struct gcr_bss *b = gcr_find_bss(gcr, pc);
+
+ if (b) {
+ /* All cell definitons will be removed, as they are attached to BSS. */
+ llist_del(&b->list);
+ talloc_free(b);
+ }
+}
+
+/* Create a new (empty) GCR list. */
+struct gcr *gcr_create(struct gsm_network *gsmnet, enum trans_type trans_type, const char *group_id)
+{
+ struct gcr *gcr;
+
+ gcr = talloc_zero(gsmnet, struct gcr);
+ if (!gcr)
+ return NULL;
+
+ INIT_LLIST_HEAD(&gcr->bss_list);
+ gcr->trans_type = trans_type;
+ gcr->timeout = GCR_DEFAULT_TIMEOUT;
+ gcr->mute_talker = true;
+ osmo_strlcpy(gcr->group_id, group_id, sizeof(gcr->group_id));
+ llist_add_tail(&gcr->list, &gsmnet->asci.gcr_lists);
+
+ return gcr;
+}
+
+/* Destroy a GCR list. */
+void gcr_destroy(struct gcr *gcr)
+{
+ /* All BSS definitons will be removed, as they are attached to GCR. */
+ llist_del(&gcr->list);
+ talloc_free(gcr);
+}
+
+/* Find GCR list by group ID. */
+struct gcr *gcr_by_group_id(struct gsm_network *gsmnet, enum trans_type trans_type, const char *group_id)
+{
+ struct gcr *gcr;
+
+ llist_for_each_entry(gcr, &gsmnet->asci.gcr_lists, list) {
+ if (gcr->trans_type == trans_type && !strcmp(gcr->group_id, group_id))
+ return gcr;
+ }
+
+ return NULL;
+}
+
+/* Find GCR list by callref. */
+struct gcr *gcr_by_callref(struct gsm_network *gsmnet, enum trans_type trans_type, uint32_t callref)
+{
+ struct gcr *most_specific_gcr = NULL, *gcr;
+ int a, b;
+ size_t most_specific_len = 0, l;
+
+ llist_for_each_entry(gcr, &gsmnet->asci.gcr_lists, list) {
+ /* Compare only the digits in Group ID with the digits in callref.
+ * callref is an integer. Only the remainder, based on Group ID length, is checked. */
+ l = strlen(gcr->group_id);
+ a = atoi(gcr->group_id);
+ OSMO_ASSERT(l < ARRAY_SIZE(pow10));
+ b = callref % pow10[l];
+ if (gcr->trans_type == trans_type && a == b) {
+ /* Get most specific GROUP ID, no matter what order they are stored. */
+ if (l > most_specific_len) {
+ most_specific_gcr = gcr;
+ most_specific_len = l;
+ }
+ }
+ }
+
+ return most_specific_gcr;
+}