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-rw-r--r--src/host/layer23/src/mobile/gsm414.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/src/host/layer23/src/mobile/gsm414.c b/src/host/layer23/src/mobile/gsm414.c
new file mode 100644
index 00000000..2f630df3
--- /dev/null
+++ b/src/host/layer23/src/mobile/gsm414.c
@@ -0,0 +1,220 @@
+/*
+ * (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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 <stdint.h>
+#include <errno.h>
+
+#include <osmocom/core/logging.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/msgb.h>
+
+#include <osmocom/gsm/gsm48.h>
+#include <osmocom/gsm/rsl.h>
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/protocol/gsm_04_14.h>
+#include <osmocom/gsm/protocol/gsm_08_58.h>
+
+#include <osmocom/bb/common/osmocom_data.h>
+#include <osmocom/bb/common/logging.h>
+
+#include <l1ctl_proto.h>
+
+int gsm48_rr_tx_rr_status(struct osmocom_ms *ms, uint8_t cause);
+int gsm48_send_rsl(struct osmocom_ms *ms, uint8_t msg_type,
+ struct msgb *msg, uint8_t link_id);
+struct msgb *gsm48_l3_msgb_alloc(void);
+
+#define loop_mode_name(mode) \
+ get_value_string(loop_mode_names, mode)
+
+static const struct value_string loop_mode_names[] = {
+ { L1CTL_TCH_LOOP_OPEN, "(OPEN)" },
+ { L1CTL_TCH_LOOP_A, "A" },
+ { L1CTL_TCH_LOOP_B, "B" },
+ { L1CTL_TCH_LOOP_C, "C" },
+ { L1CTL_TCH_LOOP_D, "D" },
+ { L1CTL_TCH_LOOP_E, "E" },
+ { L1CTL_TCH_LOOP_F, "F" },
+ { L1CTL_TCH_LOOP_I, "I" },
+ { 0, NULL }
+};
+
+static struct msgb *alloc_gsm414_msg(uint8_t msg_type)
+{
+ struct gsm48_hdr *ngh;
+ struct msgb *nmsg;
+
+ nmsg = gsm48_l3_msgb_alloc();
+ if (nmsg == NULL)
+ return NULL;
+
+ ngh = (struct gsm48_hdr *) msgb_put(nmsg, sizeof(*ngh));
+ ngh->proto_discr = GSM48_PDISC_TEST;
+ ngh->msg_type = msg_type;
+
+ return nmsg;
+}
+
+static int handle_close_tch_loop(struct osmocom_ms *ms, const struct msgb *msg)
+{
+ struct gsm48_rrlayer *rr = &ms->rrlayer;
+ const struct gsm48_hdr *gh = msgb_l3(msg);
+ unsigned int msg_len = msgb_l3len(msg);
+ struct msgb *nmsg;
+
+ /* Make sure that we have an active connection */
+ if (rr->state != GSM48_RR_ST_DEDICATED) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop requires an active connection\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ /* Make sure that the established channel is either TCH/F or TCH/H */
+ if ((rr->cd_now.chan_nr & 0xf8) != RSL_CHAN_Bm_ACCHs
+ && (rr->cd_now.chan_nr & 0xf0) != RSL_CHAN_Lm_ACCHs) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop requires a TCH/F or TCH/H connection\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ /* Check if a loop is already closed */
+ if (rr->tch_loop_mode != L1CTL_TCH_LOOP_OPEN) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop has already been closed\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ if ((msg_len - sizeof(*gh)) < 1)
+ return -EINVAL;
+
+ /* Parse type of the TCH test loop, convert to L1CTL format */
+ uint8_t gsm414_loop_mode = (gh->data[0] >> 1) & 0x1f;
+
+ /* NOTE: some bits are not specified, so they can be 0 or 1 */
+ if (gsm414_loop_mode == GSM414_LOOP_A)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_A;
+ else if (gsm414_loop_mode == GSM414_LOOP_B)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_B;
+ else if ((gsm414_loop_mode & 0x1e) == GSM414_LOOP_C)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_C;
+ else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_D)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_D;
+ else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_E)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_E;
+ else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_F)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_F;
+ else if ((gsm414_loop_mode & 0x1c) == GSM414_LOOP_I)
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_I;
+ else {
+ LOGP(DMM, LOGL_NOTICE, "Unhandled 3GPP TS 44.014 TCH loop "
+ "mode=0x%02x => rejecting\n", gsm414_loop_mode);
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N);
+ return -ENOTSUP;
+ }
+
+ LOGP(DMM, LOGL_NOTICE, "(%s) Closing 3GPP TS 44.014 TCH loop mode '%s'\n",
+ rsl_chan_nr_str(rr->cd_now.chan_nr), loop_mode_name(rr->tch_loop_mode));
+
+ /* Instruct the L1 to enable received TCH loopback mode
+ * FIXME: delay applying this mode, so we can send the ACK first */
+ l1ctl_tx_tch_mode_req(ms, rr->cd_now.mode, rr->audio_mode, rr->tch_loop_mode);
+
+ /* Craft and send the ACKnowledgement */
+ nmsg = alloc_gsm414_msg(GSM414_MT_CLOSE_TCH_LOOP_ACK);
+ if (nmsg == NULL)
+ return -ENOMEM;
+
+ return gsm48_send_rsl(ms, RSL_MT_DATA_REQ, nmsg, 0);
+}
+
+static int handle_open_tch_loop(struct osmocom_ms *ms, const struct msgb *msg)
+{
+ struct gsm48_rrlayer *rr = &ms->rrlayer;
+ struct msgb *nmsg;
+
+ /* Make sure that we have an active connection */
+ if (rr->state != GSM48_RR_ST_DEDICATED) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop requires an active connection\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ /* Make sure that the established channel is either TCH/F or TCH/H */
+ if ((rr->cd_now.chan_nr & 0xf8) != RSL_CHAN_Bm_ACCHs
+ && (rr->cd_now.chan_nr & 0xf0) != RSL_CHAN_Lm_ACCHs) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop requires a TCH/F or TCH/H connection\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ /* Check if a loop actually needs to be closed */
+ if (rr->tch_loop_mode == L1CTL_TCH_LOOP_OPEN) {
+ LOGP(DMM, LOGL_NOTICE, "TCH loop has not been closed (already open)\n");
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N_COMPAT);
+ return -EINVAL;
+ }
+
+ LOGP(DMM, LOGL_NOTICE, "(%s) Opening 3GPP TS 44.014 TCH loop mode '%s'\n",
+ rsl_chan_nr_str(rr->cd_now.chan_nr), loop_mode_name(rr->tch_loop_mode));
+
+ /* Instruct the L1 to disable the TCH loopback mode */
+ l1ctl_tx_tch_mode_req(ms, rr->cd_now.mode, rr->audio_mode, L1CTL_TCH_LOOP_OPEN);
+
+ /* Only the loop mode C needs to be ACKnowledged */
+ bool needs_ack = rr->tch_loop_mode == L1CTL_TCH_LOOP_C;
+ rr->tch_loop_mode = L1CTL_TCH_LOOP_OPEN;
+ if (!needs_ack)
+ return 0;
+
+ /* Craft and send the ACKnowledgement */
+ nmsg = alloc_gsm414_msg(GSM414_MT_OPEN_LOOP_CMD);
+ if (nmsg == NULL)
+ return -ENOMEM;
+
+ msgb_put_u8(nmsg, GSM414_OPEN_LOOP_ACK_IE);
+
+ return gsm48_send_rsl(ms, RSL_MT_DATA_REQ, nmsg, 0);
+}
+
+int gsm414_rcv_test(struct osmocom_ms *ms, const struct msgb *msg)
+{
+ const struct gsm48_hdr *gh = msgb_l3(msg);
+
+ LOGP(DMM, LOGL_INFO, "Received 3GPP TS 44.014 message '%s' (0x%02x)\n",
+ get_value_string(gsm414_msgt_names, gh->msg_type), gh->msg_type);
+
+ /* TODO: check if the test SIM (special EF.ADM) is inserted */
+ switch (gh->msg_type) {
+ case GSM414_MT_CLOSE_TCH_LOOP_CMD:
+ return handle_close_tch_loop(ms, msg);
+ case GSM414_MT_OPEN_LOOP_CMD:
+ return handle_open_tch_loop(ms, msg);
+ default:
+ LOGP(DMM, LOGL_NOTICE, "Unhandled 3GPP TS 44.014 message '%s' (0x%02x)\n",
+ get_value_string(gsm414_msgt_names, gh->msg_type), gh->msg_type);
+ gsm48_rr_tx_rr_status(ms, GSM48_RR_CAUSE_MSG_TYPE_N);
+ return -ENOTSUP;
+ }
+}