Add counters: pcu.bts.N.pch.requests.timeout

Implement T3113 for paging over PCH with default value of 7s (same as
T3113 in OsmoBSC). Increase the new counter on timeout.

Related: SYS#4878
Change-Id: I97475c3dbe2cf00b9cbfec39e93a3c65cb7f749f

8 files changed, 142 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 8070fda3..f05daaf5 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -62,6 +62,7 @@ libgprs_la_SOURCES = \
 	tbf_ul.cpp \
 	tbf_dl.cpp \
 	bts.cpp \
+	bts_pch_timer.c \
 	pdch.cpp \
 	pdch_ul_controller.c \
 	encoding.cpp \
@@ -101,6 +102,7 @@ noinst_HEADERS = \
 	tbf_ul.h \
 	tbf_dl.h \
 	bts.h \
+	bts_pch_timer.h \
 	pdch.h \
 	pdch_ul_controller.h \
 	encoding.h \
diff --git a/src/bts.cpp b/src/bts.cpp
index 4e3b770b..a96fe24e 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -133,6 +133,7 @@ static const struct rate_ctr_desc bts_ctr_description[] = {
 	{ "llc:dl_bytes",               "RLC encapsulated PDUs"},
 	{ "llc:ul_bytes",               "full PDUs received   "},
 	{ "pch:requests",		"PCH requests sent    "},
+	{ "pch:requests:timeout",	"PCH requests timeout "},
 	{ "rach:requests",		"RACH requests received"},
 	{ "11bit_rach:requests",	"11BIT_RACH requests received"},
 	{ "spb:uplink_first_segment",   "First seg of UL SPB  "},
@@ -283,6 +284,8 @@ struct gprs_rlcmac_bts* bts_alloc(struct gprs_pcu *pcu, uint8_t bts_nr)
 
 	llist_add_tail(&bts->list, &pcu->bts_list);
 
+	INIT_LLIST_HEAD(&bts->pch_timer);
+
 	return bts;
 }
 
diff --git a/src/bts.h b/src/bts.h
index c28bd973..5e45527c 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -126,6 +126,7 @@ enum {
 	CTR_LLC_DL_BYTES,
 	CTR_LLC_UL_BYTES,
 	CTR_PCH_REQUESTS,
+	CTR_PCH_REQUESTS_TIMEDOUT,
 	CTR_RACH_REQUESTS,
 	CTR_11BIT_RACH_REQUESTS,
 	CTR_SPB_UL_FIRST_SEGMENT,
@@ -263,6 +264,9 @@ struct gprs_rlcmac_bts {
 	struct osmo_stat_item_group *statg;
 
 	struct GprsMsStorage *ms_store;
+
+	/* List of struct bts_pch_timer for active PCH pagings */
+	struct llist_head pch_timer;
 };
 
 #ifdef __cplusplus
diff --git a/src/bts_pch_timer.c b/src/bts_pch_timer.c
new file mode 100644
index 00000000..386a583c
--- /dev/null
+++ b/src/bts_pch_timer.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Oliver Smith
+ *
+ * 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 <string.h>
+
+#include <osmocom/core/logging.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/tdef.h>
+#include <osmocom/core/utils.h>
+
+#include <gprs_debug.h>
+#include <gprs_pcu.h>
+#include <bts_pch_timer.h>
+
+static struct bts_pch_timer *bts_pch_timer_get(struct gprs_rlcmac_bts *bts, const char *imsi)
+{
+	struct bts_pch_timer *p;
+
+	llist_for_each_entry(p, &bts->pch_timer, entry) {
+		if (strcmp(p->imsi, imsi) == 0)
+			return p;
+	}
+
+	return NULL;
+}
+
+static void bts_pch_timer_remove(struct bts_pch_timer *p)
+{
+	osmo_timer_del(&p->T3113);
+	llist_del(&p->entry);
+
+	LOGP(DPCU, LOGL_DEBUG, "PCH paging timer stopped for IMSI=%s\n", p->imsi);
+	talloc_free(p);
+}
+
+static void T3113_callback(void *data)
+{
+	struct bts_pch_timer *p = data;
+
+	LOGP(DPCU, LOGL_INFO, "PCH paging timeout for IMSI=%s\n", p->imsi);
+	bts_do_rate_ctr_inc(p->bts, CTR_PCH_REQUESTS_TIMEDOUT);
+	bts_pch_timer_remove(p);
+}
+
+void bts_pch_timer_start(struct gprs_rlcmac_bts *bts, const char *imsi)
+{
+	if (bts_pch_timer_get(bts, imsi))
+		return;
+
+	struct bts_pch_timer *p;
+	p = talloc_zero(bts, struct bts_pch_timer);
+	llist_add_tail(&p->entry, &bts->pch_timer);
+	osmo_strlcpy(p->imsi, imsi, sizeof(p->imsi));
+	p->bts = bts;
+
+	struct osmo_tdef *tdef = osmo_tdef_get_entry(the_pcu->T_defs, 3113);
+	OSMO_ASSERT(tdef);
+	osmo_timer_setup(&p->T3113, T3113_callback, p);
+	osmo_timer_schedule(&p->T3113, tdef->val, 0);
+
+	LOGP(DPCU, LOGL_DEBUG, "PCH paging timer started for IMSI=%s\n", p->imsi);
+}
+
+void bts_pch_timer_stop(struct gprs_rlcmac_bts *bts, const char *imsi)
+{
+	struct bts_pch_timer *p = bts_pch_timer_get(bts, imsi);
+
+	if (p)
+		bts_pch_timer_remove(p);
+}
diff --git a/src/bts_pch_timer.h b/src/bts_pch_timer.h
new file mode 100644
index 00000000..91bebedb
--- /dev/null
+++ b/src/bts_pch_timer.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * Author: Oliver Smith
+ *
+ * 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/gsm/protocol/gsm_23_003.h>
+
+#include <bts.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct bts_pch_timer {
+	struct llist_head entry;
+	struct gprs_rlcmac_bts *bts;
+	struct osmo_timer_list T3113;
+	char imsi[OSMO_IMSI_BUF_SIZE];
+};
+
+void bts_pch_timer_start(struct gprs_rlcmac_bts *bts, const char *imsi);
+void bts_pch_timer_stop(struct gprs_rlcmac_bts *bts, const char *imsi);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/gprs_pcu.c b/src/gprs_pcu.c
index 37563ecf..a7bab8d4 100644
--- a/src/gprs_pcu.c
+++ b/src/gprs_pcu.c
@@ -30,6 +30,7 @@
 struct gprs_pcu *the_pcu;
 
 static struct osmo_tdef T_defs_pcu[] = {
+	{ .T=3113,  .default_val=7, .unit=OSMO_TDEF_S, .desc="Timeout for paging", .val=0 },
 	{ .T=3190,  .default_val=5,   .unit=OSMO_TDEF_S,  .desc="Return to packet idle mode after Packet DL Assignment on CCCH (s)", .val=0},
 	{ .T=3141,  .default_val=10, .unit=OSMO_TDEF_S, .desc="Timeout for contention resolution procedure (s)", .val=0 },
 	{ .T=PCU_TDEF_NEIGH_RESOLVE_TO,    .default_val=1000,  .unit=OSMO_TDEF_MS,   .desc="[ARFCN+BSIC]->[RAC+CI] resolution timeout (ms)", .val=0 },
diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp
index ffa656c3..22b12dfc 100644
--- a/src/gprs_rlcmac.cpp
+++ b/src/gprs_rlcmac.cpp
@@ -26,6 +26,7 @@ extern "C" {
 #include <pcu_l1_if.h>
 #include <gprs_rlcmac.h>
 #include <bts.h>
+#include <bts_pch_timer.h>
 #include <encoding.h>
 #include <tbf.h>
 #include <gprs_debug.h>
@@ -48,6 +49,7 @@ int gprs_rlcmac_paging_request(struct gprs_rlcmac_bts *bts, const struct osmo_mo
 		return -1;
 	}
 	bts_do_rate_ctr_inc(bts, CTR_PCH_REQUESTS);
+	bts_pch_timer_start(bts, mi->imsi);
 	pcu_l1if_tx_pch(bts, paging_request, plen, pgroup);
 	bitvec_free(paging_request);
 
diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
index b5f9f01d..5ca02d95 100644
--- a/src/tbf_ul.cpp
+++ b/src/tbf_ul.cpp
@@ -20,6 +20,7 @@
  */
 
 #include <bts.h>
+#include <bts_pch_timer.h>
 #include <tbf.h>
 #include <tbf_ul.h>
 #include <rlc.h>
@@ -494,6 +495,7 @@ int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged(
 					  "Decoded premier TLLI=0x%08x of UL DATA TFI=%d.\n",
 					  new_tlli, rlc->tfi);
 				update_ms(new_tlli, GPRS_RLCMAC_UL_TBF);
+				bts_pch_timer_stop(bts, ms_imsi(ms()));
 			} else if (new_tlli != GSM_RESERVED_TMSI && new_tlli != tlli()) {
 				LOGPTBFUL(this, LOGL_NOTICE,
 					  "Decoded TLLI=%08x mismatch on UL DATA TFI=%d. (Ignoring due to contention resolution)\n",