[bsc] Move the GSM 04.08 helper functions to gsm_04_08_utils.c

The existing gsm_04_08.c implementation is mixing BSC and MSC
behavior. Move some simple parsing and generation functions over
to gsm_04_08_utils.c to allow a different MSC to define the policy.

1 files changed, 310 insertions, 0 deletions

diff --git a/openbsc/src/gsm_04_08_utils.c b/openbsc/src/gsm_04_08_utils.c
new file mode 100644
index 000000000..50deb2bcb
--- /dev/null
+++ b/openbsc/src/gsm_04_08_utils.c
@@ -0,0 +1,310 @@
+/* GSM Mobile Radio Interface Layer 3 messages on the A-bis interface
+ * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0
+ * utility functions
+ */
+
+/* (C) 2008-2009 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 <netinet/in.h>
+
+#include <openbsc/msgb.h>
+#include <openbsc/debug.h>
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/transaction.h>
+
+#define GSM48_ALLOC_SIZE	1024
+#define GSM48_ALLOC_HEADROOM	128
+
+/* should ip.access BTS use direct RTP streams between each other (1),
+ * or should OpenBSC always act as RTP relay/proxy in between (0) ? */
+int ipacc_rtp_direct = 1;
+
+
+const char *gsm0408_cc_msg_names[] = {
+	"unknown 0x00",
+	"ALERTING",
+	"CALL_PROC",
+	"PROGRESS",
+	"ESTAB",
+	"SETUP",
+	"ESTAB_CONF",
+	"CONNECT",
+	"CALL_CONF",
+	"START_CC",
+	"unknown 0x0a",
+	"RECALL",
+	"unknown 0x0c",
+	"unknown 0x0d",
+	"EMERG_SETUP",
+	"CONNECT_ACK",
+	"USER_INFO",
+	"unknown 0x11",
+	"unknown 0x12",
+	"MODIFY_REJECT",
+	"unknown 0x14",
+	"unknown 0x15",
+	"unknown 0x16",
+	"MODIFY",
+	"HOLD",
+	"HOLD_ACK",
+	"HOLD_REJ",
+	"unknown 0x1b",
+	"RETR",
+	"RETR_ACK",
+	"RETR_REJ",
+	"MODIFY_COMPL",
+	"unknown 0x20",
+	"unknown 0x21",
+	"unknown 0x22",
+	"unknown 0x23",
+	"unknown 0x24",
+	"DISCONNECT",
+	"unknown 0x26",
+	"unknown 0x27",
+	"unknown 0x28",
+	"unknown 0x29",
+	"RELEASE_COMPL",
+	"unknown 0x2b",
+	"unknown 0x2c",
+	"RELEASE",
+	"unknown 0x2e",
+	"unknown 0x2f",
+	"unknown 0x30",
+	"STOP_DTMF",
+	"STOP_DTMF_ACK",
+	"unknown 0x33",
+	"STATUS_ENQ",
+	"START_DTMF",
+	"START_DTMF_ACK",
+	"START_DTMF_REJ",
+	"unknown 0x38",
+	"CONG_CTRL",
+	"FACILITY",
+	"unknown 0x3b",
+	"STATUS",
+	"unknown 0x3c",
+	"NOTIFY",
+	"unknown 0x3f",
+};
+
+
+struct msgb *gsm48_msgb_alloc(void)
+{
+	return msgb_alloc_headroom(GSM48_ALLOC_SIZE, GSM48_ALLOC_HEADROOM,
+				   "GSM 04.08");
+}
+
+int gsm48_sendmsg(struct msgb *msg, struct gsm_trans *trans)
+{
+	struct gsm48_hdr *gh = (struct gsm48_hdr *) msg->data;
+
+	/* if we get passed a transaction reference, do some common
+	 * work that the caller no longer has to do */
+	if (trans) {
+		gh->proto_discr = trans->protocol | (trans->transaction_id << 4);
+		msg->lchan = trans->lchan;
+	}
+
+	if (msg->lchan) {
+		msg->trx = msg->lchan->ts->trx;
+
+		if ((gh->proto_discr & GSM48_PDISC_MASK) == GSM48_PDISC_CC)
+			DEBUGP(DCC, "(bts %d trx %d ts %d ti %02x) "
+				"Sending '%s' to MS.\n", msg->trx->bts->nr,
+				msg->trx->nr, msg->lchan->ts->nr,
+				gh->proto_discr & 0xf0,
+				gsm0408_cc_msg_names[gh->msg_type & 0x3f]);
+		else
+			DEBUGP(DCC, "(bts %d trx %d ts %d pd %02x) "
+				"Sending 0x%02x to MS.\n", msg->trx->bts->nr,
+				msg->trx->nr, msg->lchan->ts->nr,
+				gh->proto_discr, gh->msg_type);
+	}
+
+	msg->l3h = msg->data;
+
+	return rsl_data_request(msg, 0);
+}
+
+static void to_bcd(u_int8_t *bcd, u_int16_t val)
+{
+	bcd[2] = val % 10;
+	val = val / 10;
+	bcd[1] = val % 10;
+	val = val / 10;
+	bcd[0] = val % 10;
+	val = val / 10;
+}
+
+void gsm0408_generate_lai(struct gsm48_loc_area_id *lai48, u_int16_t mcc,
+			 u_int16_t mnc, u_int16_t lac)
+{
+	u_int8_t bcd[3];
+
+	to_bcd(bcd, mcc);
+	lai48->digits[0] = bcd[0] | (bcd[1] << 4);
+	lai48->digits[1] = bcd[2];
+
+	to_bcd(bcd, mnc);
+	/* FIXME: do we need three-digit MNC? See Table 10.5.3 */
+#if 0
+	lai48->digits[1] |= bcd[2] << 4;
+	lai48->digits[2] = bcd[0] | (bcd[1] << 4);
+#else
+	lai48->digits[1] |= 0xf << 4;
+	lai48->digits[2] = bcd[1] | (bcd[2] << 4);
+#endif
+
+	lai48->lac = htons(lac);
+}
+
+int generate_mid_from_tmsi(u_int8_t *buf, u_int32_t tmsi)
+{
+	u_int32_t *tptr = (u_int32_t *) &buf[3];
+
+	buf[0] = GSM48_IE_MOBILE_ID;
+	buf[1] = GSM48_TMSI_LEN;
+	buf[2] = 0xf0 | GSM_MI_TYPE_TMSI;
+	*tptr = htonl(tmsi);
+
+	return 7;
+}
+
+/* Section 9.1.8 / Table 9.9 */
+struct chreq {
+	u_int8_t val;
+	u_int8_t mask;
+	enum chreq_type type;
+};
+
+/* If SYSTEM INFORMATION TYPE 4 NECI bit == 1 */
+static const struct chreq chreq_type_neci1[] = {
+	{ 0xa0, 0xe0, CHREQ_T_EMERG_CALL },
+	{ 0xc0, 0xe0, CHREQ_T_CALL_REEST_TCH_F },
+	{ 0x68, 0xfc, CHREQ_T_CALL_REEST_TCH_H },
+	{ 0x6c, 0xfc, CHREQ_T_CALL_REEST_TCH_H_DBL },
+	{ 0xe0, 0xe0, CHREQ_T_SDCCH },
+	{ 0x40, 0xf0, CHREQ_T_VOICE_CALL_TCH_H },
+	{ 0x50, 0xf0, CHREQ_T_DATA_CALL_TCH_H },
+	{ 0x00, 0xf0, CHREQ_T_LOCATION_UPD },
+	{ 0x10, 0xf0, CHREQ_T_SDCCH },
+	{ 0x80, 0xe0, CHREQ_T_PAG_R_ANY },
+	{ 0x20, 0xf0, CHREQ_T_PAG_R_TCH_F },
+	{ 0x30, 0xf0, CHREQ_T_PAG_R_TCH_FH },
+};
+
+/* If SYSTEM INFORMATION TYPE 4 NECI bit == 0 */
+static const struct chreq chreq_type_neci0[] = {
+	{ 0xa0, 0xe0, CHREQ_T_EMERG_CALL },
+	{ 0xc0, 0xe0, CHREQ_T_CALL_REEST_TCH_H },
+	{ 0xe0, 0xe0, CHREQ_T_TCH_F },
+	{ 0x50, 0xf0, CHREQ_T_DATA_CALL_TCH_H },
+	{ 0x00, 0xe0, CHREQ_T_LOCATION_UPD },
+	{ 0x80, 0xe0, CHREQ_T_PAG_R_ANY },
+	{ 0x20, 0xf0, CHREQ_T_PAG_R_TCH_F },
+	{ 0x30, 0xf0, CHREQ_T_PAG_R_TCH_FH },
+};
+
+static const enum gsm_chan_t ctype_by_chreq[] = {
+	[CHREQ_T_EMERG_CALL]		= GSM_LCHAN_TCH_F,
+	[CHREQ_T_CALL_REEST_TCH_F]	= GSM_LCHAN_TCH_F,
+	[CHREQ_T_CALL_REEST_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_CALL_REEST_TCH_H_DBL]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_SDCCH]			= GSM_LCHAN_SDCCH,
+	[CHREQ_T_TCH_F]			= GSM_LCHAN_TCH_F,
+	[CHREQ_T_VOICE_CALL_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_DATA_CALL_TCH_H]	= GSM_LCHAN_TCH_H,
+	[CHREQ_T_LOCATION_UPD]		= GSM_LCHAN_SDCCH,
+	[CHREQ_T_PAG_R_ANY]		= GSM_LCHAN_SDCCH,
+	[CHREQ_T_PAG_R_TCH_F]		= GSM_LCHAN_TCH_F,
+	[CHREQ_T_PAG_R_TCH_FH]		= GSM_LCHAN_TCH_F,
+};
+
+static const enum gsm_chreq_reason_t reason_by_chreq[] = {
+	[CHREQ_T_EMERG_CALL]		= GSM_CHREQ_REASON_EMERG,
+	[CHREQ_T_CALL_REEST_TCH_F]	= GSM_CHREQ_REASON_CALL,
+	[CHREQ_T_CALL_REEST_TCH_H]	= GSM_CHREQ_REASON_CALL,
+	[CHREQ_T_CALL_REEST_TCH_H_DBL]	= GSM_CHREQ_REASON_CALL,
+	[CHREQ_T_SDCCH]			= GSM_CHREQ_REASON_OTHER,
+	[CHREQ_T_TCH_F]			= GSM_CHREQ_REASON_OTHER,
+	[CHREQ_T_VOICE_CALL_TCH_H]	= GSM_CHREQ_REASON_OTHER,
+	[CHREQ_T_DATA_CALL_TCH_H]	= GSM_CHREQ_REASON_OTHER,
+	[CHREQ_T_LOCATION_UPD]		= GSM_CHREQ_REASON_LOCATION_UPD,
+	[CHREQ_T_PAG_R_ANY]		= GSM_CHREQ_REASON_PAG,
+	[CHREQ_T_PAG_R_TCH_F]		= GSM_CHREQ_REASON_PAG,
+	[CHREQ_T_PAG_R_TCH_FH]		= GSM_CHREQ_REASON_PAG,
+};
+
+enum gsm_chan_t get_ctype_by_chreq(struct gsm_bts *bts, u_int8_t ra)
+{
+	int i;
+	/* FIXME: determine if we set NECI = 0 in the BTS SI4 */
+
+	for (i = 0; i < ARRAY_SIZE(chreq_type_neci0); i++) {
+		const struct chreq *chr = &chreq_type_neci0[i];
+		if ((ra & chr->mask) == chr->val)
+			return ctype_by_chreq[chr->type];
+	}
+	fprintf(stderr, "Unknown CHANNEL REQUEST RQD 0x%02x\n", ra);
+	return GSM_LCHAN_SDCCH;
+}
+
+enum gsm_chreq_reason_t get_reason_by_chreq(struct gsm_bts *bts, u_int8_t ra)
+{
+	int i;
+	/* FIXME: determine if we set NECI = 0 in the BTS SI4 */
+
+	for (i = 0; i < ARRAY_SIZE(chreq_type_neci0); i++) {
+		const struct chreq *chr = &chreq_type_neci0[i];
+		if ((ra & chr->mask) == chr->val)
+			return reason_by_chreq[chr->type];
+	}
+	fprintf(stderr, "Unknown CHANNEL REQUEST REASON 0x%02x\n", ra);
+	return GSM_CHREQ_REASON_OTHER;
+}
+
+/* 7.1.7 and 9.1.7: RR CHANnel RELease */
+int gsm48_send_rr_release(struct gsm_lchan *lchan)
+{
+	struct msgb *msg = gsm48_msgb_alloc();
+	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
+	u_int8_t *cause;
+
+	msg->lchan = lchan;
+	gh->proto_discr = GSM48_PDISC_RR;
+	gh->msg_type = GSM48_MT_RR_CHAN_REL;
+
+	cause = msgb_put(msg, 1);
+	cause[0] = GSM48_RR_CAUSE_NORMAL;
+
+	DEBUGP(DRR, "Sending Channel Release: Chan: Number: %d Type: %d\n",
+		lchan->nr, lchan->type);
+
+	/* Send actual release request to MS */
+	gsm48_sendmsg(msg, NULL);
+	/* FIXME: Start Timer T3109 */
+
+	/* Deactivate the SACCH on the BTS side */
+	return rsl_deact_sacch(lchan);
+}
+