Handover support to common part of BTS code

10 files changed, 222 insertions, 2 deletions

diff --git a/include/osmo-bts/handover.h b/include/osmo-bts/handover.h
new file mode 100644
index 00000000..6d857744
--- /dev/null
+++ b/include/osmo-bts/handover.h
@@ -0,0 +1,8 @@
+#ifndef HANDOVER_H
+#define HANDOVER_H
+
+void handover_rach(struct gsm_bts_trx *trx, uint8_t chan_nr, 
+	struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay);
+void handover_frame(struct gsm_lchan *lchan);
+
+#endif /* HANDOVER_H */
diff --git a/include/osmo-bts/logging.h b/include/osmo-bts/logging.h
index bcb1fcb0..fda00fd6 100644
--- a/include/osmo-bts/logging.h
+++ b/include/osmo-bts/logging.h
@@ -17,6 +17,7 @@ enum {
 	DPCU,
 	DTRX,
 	DLOOP,
+	DHO,
 	DABIS,
 	DRTP,
 	DSUM,
diff --git a/include/osmo-bts/rsl.h b/include/osmo-bts/rsl.h
index cc39f813..6cb40dd2 100644
--- a/include/osmo-bts/rsl.h
+++ b/include/osmo-bts/rsl.h
@@ -23,6 +23,7 @@ int rsl_tx_chan_act_ack(struct gsm_lchan *lchan);
 int rsl_tx_chan_act_nack(struct gsm_lchan *lchan, uint8_t cause);
 int rsl_tx_conn_fail(struct gsm_lchan *lchan, uint8_t cause);
 int rsl_tx_rf_rel_ack(struct gsm_lchan *lchan);
+int rsl_tx_hando_det(struct gsm_lchan *lchan, uint8_t *ho_delay);
 
 /* call-back for LAPDm code, called when it wants to send msgs UP */
 int lapdm_rll_tx_cb(struct msgb *msg, struct lapdm_entity *le, void *ctx);
diff --git a/src/common/Makefile.am b/src/common/Makefile.am
index 1c6ff9e2..acde056b 100644
--- a/src/common/Makefile.am
+++ b/src/common/Makefile.am
@@ -5,4 +5,4 @@ LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOTRAU_LIBS)
 noinst_LIBRARIES = libbts.a
 libbts_a_SOURCES = gsm_data_shared.c sysinfo.c logging.c abis.c oml.c bts.c \
 		   rsl.c vty.c paging.c measurement.c amr.c lchan.c \
-		   load_indication.c pcu_sock.c l1sap.c
+		   load_indication.c pcu_sock.c l1sap.c handover.c
diff --git a/src/common/bts.c b/src/common/bts.c
index 9e1d9549..47339230 100644
--- a/src/common/bts.c
+++ b/src/common/bts.c
@@ -74,6 +74,8 @@ int bts_init(struct gsm_bts *bts)
 	load_timer_start(bts);
 	btsb->rtp_jitter_buf_ms = 100;
 	btsb->max_ta = 63;
+	btsb->ny1 = 4;
+	btsb->t3105_ms = 300;
 
 	/* default RADIO_LINK_TIMEOUT */
 	btsb->radio_link_timeout = 32;
diff --git a/src/common/handover.c b/src/common/handover.c
new file mode 100644
index 00000000..3d0a5e98
--- /dev/null
+++ b/src/common/handover.c
@@ -0,0 +1,138 @@
+/* Paging message encoding + queue management */
+
+/* (C) 2012-2013 by Harald Welte <laforge@gnumonks.org>
+ *                  Andreas Eversberg <jolly@eversberg.eu>
+ *
+ * All Rights Reserved
+ *
+ * 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 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 <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/rsl.h>
+
+#include <osmo-bts/bts.h>
+#include <osmo-bts/rsl.h>
+#include <osmo-bts/l1sap.h>
+#include <osmo-bts/logging.h>
+#include <osmo-bts/handover.h>
+
+/* Transmit a handover related PHYS INFO on given lchan */
+static int ho_tx_phys_info(struct gsm_lchan *lchan, uint8_t ta)
+{
+	struct msgb *msg = msgb_alloc_headroom(1024, 128, "PHYS INFO");
+	struct gsm48_hdr *gh;
+
+	if (!msg)
+		return -ENOMEM;
+
+	LOGP(DHO, LOGL_INFO, "Sending PHYSICAL INFORMATION to MS.\n");
+
+	/* Build RSL UNITDATA REQUEST message with 04.08 PHYS INFO */
+	msg->l3h = msg->data;
+	gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh));
+	gh->proto_discr = GSM48_PDISC_RR;
+	gh->msg_type = GSM48_MT_RR_HANDO_INFO;
+	msgb_put_u8(msg, ta);
+
+	rsl_rll_push_l3(msg, RSL_MT_UNIT_DATA_REQ, gsm_lchan2chan_nr(lchan),
+		0x00, 0);
+
+	lapdm_rslms_recvmsg(msg, &lchan->lapdm_ch);
+}
+
+/* timer call-back for T3105 (handover PHYS INFO re-transmit) */
+static void ho_t3105_cb(void *data)
+{
+	struct gsm_lchan *lchan = data;
+	struct gsm_bts *bts = lchan->ts->trx->bts;
+	struct gsm_bts_role_bts *btsb = bts->role;
+	
+	LOGP(DHO, LOGL_INFO, "T3105 timeout (%d resends left)\n",
+		btsb->ny1 - lchan->ho.phys_info_count);
+
+	if (lchan->state != LCHAN_S_ACTIVE) {
+		LOGP(DHO, LOGL_NOTICE, "NY1 reached, sending CONNection "
+			"FAILure to BSC.\n");
+		return;
+	}
+
+	if (lchan->ho.phys_info_count >= btsb->ny1) {
+		/* HO Abort */
+		rsl_tx_conn_fail(lchan, RSL_ERR_HANDOVER_ACC_FAIL);
+		return;
+	}
+
+	ho_tx_phys_info(lchan, lchan->rqd_ta);
+	lchan->ho.phys_info_count++;
+	osmo_timer_schedule(&lchan->ho.t3105, 0, btsb->t3105_ms * 1000);
+}
+
+/* received random access on dedicated channel */
+void handover_rach(struct gsm_bts_trx *trx, uint8_t chan_nr,
+	struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay)
+{
+	struct gsm_bts *bts = trx->bts;
+	struct gsm_bts_role_bts *btsb = bts->role;
+
+	/* Ignore invalid handover ref */
+	if (lchan->ho.ref != ra) {
+		LOGP(DHO, LOGL_INFO, "RACH on decicated channel received, but "
+			"ra=0x%02x != expected ref=0x%02x. (This is no bug)\n",
+			ra, lchan->ho.ref);
+		return;
+	}
+
+	LOGP(DHO, LOGL_NOTICE, "RACH on decicated channel received with "
+		"TA=%u\n", acc_delay);
+
+	/* Set timing advance */
+	lchan->rqd_ta = acc_delay;
+
+	/* Stop handover detection, wait for valid frame */
+	lchan->ho.active = 2;
+	l1sap_chan_modify(trx, chan_nr);
+
+	/* Send HANDover DETect to BSC */
+	rsl_tx_hando_det(lchan, &acc_delay);
+
+	/* Send PHYS INFO */
+	lchan->ho.phys_info_count = 1;
+	ho_tx_phys_info(lchan, acc_delay);
+
+	/* Start T3105 */
+	LOGP(DHO, LOGL_DEBUG, "Starting T3105 with %u ms\n", btsb->t3105_ms);
+	lchan->ho.t3105.cb = ho_t3105_cb;
+	lchan->ho.t3105.data = lchan;
+	osmo_timer_schedule(&lchan->ho.t3105, 0, btsb->t3105_ms * 1000);
+}
+
+/* received frist valid data frame on dedicated channel */
+void handover_frame(struct gsm_lchan *lchan)
+{
+	LOGP(DHO, LOGL_INFO, "First valid frame detected\n");
+
+	/* Stop T3105 */
+	if (osmo_timer_pending(&lchan->ho.t3105))
+		osmo_timer_del(&lchan->ho.t3105);
+
+	/* Handover process is done */
+	lchan->ho.active = 0;
+}
+
diff --git a/src/common/l1sap.c b/src/common/l1sap.c
index daeba9c9..ea47cbc2 100644
--- a/src/common/l1sap.c
+++ b/src/common/l1sap.c
@@ -44,6 +44,7 @@
 #include <osmo-bts/bts.h>
 #include <osmo-bts/rsl.h>
 #include <osmo-bts/bts_model.h>
+#include <osmo-bts/handover.h>
 
 static int l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap);
 
@@ -701,6 +702,10 @@ static int l1sap_ph_data_ind(struct gsm_bts_trx *trx,
 		return -EINVAL;
 	}
 
+	/* report first valid received frame to handover process */
+	if (lchan->ho.active == 2)
+		handover_frame(lchan);
+
 	if (L1SAP_IS_LINK_SACCH(link_id)) {
 		radio_link_timeout(lchan, 0);
 		le = &lchan->lapdm_ch.lapdm_acch;
@@ -792,6 +797,25 @@ static int l1sap_tch_ind(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap,
 	return 0;
 }
 
+/* special case where handover RACH is detected */
+static int l1sap_handover_rach(struct gsm_bts_trx *trx,
+	 struct osmo_phsap_prim *l1sap, struct ph_rach_ind_param *rach_ind)
+{
+	struct gsm_lchan *lchan;
+	uint8_t chan_nr;
+	uint8_t tn, ss;
+
+	chan_nr = rach_ind->chan_nr;
+	tn = L1SAP_CHAN2TS(chan_nr);
+	ss = l1sap_chan2ss(chan_nr);
+	lchan = &trx->ts[tn].lchan[ss];
+
+	handover_rach(trx, chan_nr, lchan, rach_ind->ra, rach_ind->acc_delay);
+
+	/* must return 0, so in case of msg at l1sap, it will be freed */
+	return 0;
+}
+
 /* RACH received from bts model */
 static int l1sap_ph_rach_ind(struct gsm_bts_trx *trx,
 	 struct osmo_phsap_prim *l1sap, struct ph_rach_ind_param *rach_ind)
@@ -811,6 +835,10 @@ static int l1sap_ph_rach_ind(struct gsm_bts_trx *trx,
 		return 0;
 	}
 
+	/* check for handover rach */
+	if (trx != bts->c0 && rach_ind->chan_nr != 0x88)
+		return l1sap_handover_rach(trx, l1sap, rach_ind);
+
 	/* check for packet access */
 	if (trx == bts->c0
 	 && L1SAP_IS_PACKET_RACH(rach_ind->ra)) {
diff --git a/src/common/logging.c b/src/common/logging.c
index 411a2dbe..d07c9ab2 100644
--- a/src/common/logging.c
+++ b/src/common/logging.c
@@ -58,6 +58,7 @@ static struct log_info_cat bts_log_info_cat[] = {
 	[DMEAS] = {
 		.name = "DMEAS",
 		.description = "Radio Measurement Processing",
+		.color = "\033[1;38m",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
 	[DPAG]	= {
@@ -113,6 +114,12 @@ static struct log_info_cat bts_log_info_cat[] = {
 		.color = "\033[0;34m",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
+	[DHO] = {
+		.name = "DHO",
+		.description = "Handover",
+		.color = "\033[0;37m",
+		.enabled = 1, .loglevel = LOGL_NOTICE,
+	},
 #if 0
 	[DNS] = {
 		.name = "DNS",
diff --git a/src/common/oml.c b/src/common/oml.c
index a381d1ae..573f898d 100644
--- a/src/common/oml.c
+++ b/src/common/oml.c
@@ -510,7 +510,8 @@ static int oml_rx_set_bts_attr(struct gsm_bts *bts, struct msgb *msg)
 	}
 
 	/* 9.4.10 BTS Air Timer */
-	if (TLVP_PRESENT(&tp, NM_ATT_BTS_AIR_TIMER))
+	if (TLVP_PRESENT(&tp, NM_ATT_BTS_AIR_TIMER)
+	 && *TLVP_VAL(&tp, NM_ATT_BTS_AIR_TIMER) > 0)
 		btsb->t3105_ms = *TLVP_VAL(&tp, NM_ATT_BTS_AIR_TIMER) * 10;
 
 	/* 9.4.37 NY1 */
diff --git a/src/common/rsl.c b/src/common/rsl.c
index be335e03..3d9c8f36 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -547,6 +547,28 @@ int rsl_tx_chan_act_ack(struct gsm_lchan *lchan)
 	return abis_bts_rsl_sendmsg(msg);
 }
 
+/* 8.4.7 sending HANDOver DETection */
+int rsl_tx_hando_det(struct gsm_lchan *lchan, uint8_t *ho_delay)
+{
+	struct msgb *msg;
+	uint8_t chan_nr = gsm_lchan2chan_nr(lchan);
+
+	LOGP(DRSL, LOGL_INFO, "Sending HANDOver DETect\n");
+
+	msg = rsl_msgb_alloc(sizeof(struct abis_rsl_dchan_hdr));
+	if (!msg)
+		return -ENOMEM;
+
+	/* 9.3.17 Access Delay */
+	if (ho_delay)
+		msgb_tv_put(msg, RSL_IE_ACCESS_DELAY, *ho_delay);
+
+	rsl_dch_push_hdr(msg, RSL_MT_HANDO_DET, chan_nr);
+	msg->trx = lchan->ts->trx;
+
+	return abis_bts_rsl_sendmsg(msg);
+}
+
 /* 8.4.3 sending CHANnel ACTIVation Negative ACK */
 int rsl_tx_chan_act_nack(struct gsm_lchan *lchan, uint8_t cause)
 {
@@ -715,6 +737,12 @@ static int rsl_rx_chan_activ(struct msgb *msg)
 		memset(&lchan->encr, 0, sizeof(lchan->encr));
 
 	/* 9.3.9 Handover Reference */
+	if ((type == RSL_ACT_INTER_ASYNC ||
+	     type == RSL_ACT_INTER_SYNC) &&
+	    TLVP_PRESENT(&tp, RSL_IE_HANDO_REF)) {
+		lchan->ho.active = 1;
+		lchan->ho.ref = *TLVP_VAL(&tp, RSL_IE_HANDO_REF);
+	}
 
 	/* 9.3.4 BS Power */
 	if (TLVP_PRESENT(&tp, RSL_IE_BS_POWER))
@@ -807,6 +835,12 @@ static int rsl_rx_rf_chan_rel(struct gsm_lchan *lchan, uint8_t chan_nr)
 	}
 
 	lchan->rel_act_kind = LCHAN_REL_ACT_RSL;
+
+	/* deactivate handover RACH detection and timer */
+	lchan->ho.active = 0;
+	if (osmo_timer_pending(&lchan->ho.t3105))
+		osmo_timer_del(&lchan->ho.t3105);
+
 	l1sap_chan_rel(lchan->ts->trx, chan_nr);
 
 	lapdm_channel_exit(&lchan->lapdm_ch);