TBF: implement independent T31xx timers

Previously TBF got single timer so the pending timer was automatically
cancelled when new one was scheduled. Let's make it more robust by
implementing independent T31 xx timers from 3GPP TS 44.060 §13.2 with
corresponding start/stop functions and counters.

The semantics of the timers is preserved as before: pending timers are
restarted unconditionally. It might be neecessary to change this later on
after spec review.

N. B. T0: used for assign/reject timeouts, have to be properly
attributed and documented first.

Change-Id: I0305873ca47534f53441247217881da59625e1f7
Related: OS#2407

1 files changed, 145 insertions, 66 deletions

diff --git a/src/tbf.cpp b/src/tbf.cpp
index 18059ace..a5eedd93 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -32,6 +32,7 @@
 
 extern "C" {
 #include <osmocom/core/msgb.h>
+#include <osmocom/core/utils.h>
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/stats.h>
 }
@@ -58,6 +59,14 @@ const struct value_string gprs_rlcmac_tbf_ul_ass_state_names[] = {
  	{ 0, NULL }
 };
 
+static const struct value_string tbf_timers_names[] = {
+	OSMO_VALUE_STRING(T3169),
+	OSMO_VALUE_STRING(T3191),
+	OSMO_VALUE_STRING(T3193),
+	OSMO_VALUE_STRING(T3195),
+	{ 0, NULL }
+};
+
 static const struct rate_ctr_desc tbf_ctr_description[] = {
         { "rlc.nacked",                     "RLC Nacked " },
 };
@@ -182,6 +191,7 @@ gprs_rlcmac_tbf::gprs_rlcmac_tbf(BTS *bts_, gprs_rlcmac_tbf_direction dir) :
 	 * Just set them to 0 like talloc_zero did */
 	memset(&pdch, 0, sizeof(pdch));
 	memset(&timer, 0, sizeof(timer));
+	memset(&T31, 0, sizeof(T31));
 	memset(&m_rlc, 0, sizeof(m_rlc));
 	memset(&gsm_timer, 0, sizeof(gsm_timer));
 
@@ -323,7 +333,7 @@ void gprs_rlcmac_tbf::merge_and_clear_ms(GprsMs *old_ms)
 
 	/* Clean up the old MS object */
 	/* TODO: Use timer? */
-	if (old_ms->ul_tbf() && old_ms->ul_tbf()->T == 0) {
+	if (old_ms->ul_tbf() && !old_ms->ul_tbf()->timers_pending(T_MAX)) {
 		if (old_ms->ul_tbf() == this) {
 			LOGP(DRLCMAC, LOGL_ERROR,
 				"%s is referred by the old MS "
@@ -334,7 +344,7 @@ void gprs_rlcmac_tbf::merge_and_clear_ms(GprsMs *old_ms)
 			tbf_free(old_ms->ul_tbf());
 		}
 	}
-	if (old_ms->dl_tbf() && old_ms->dl_tbf()->T == 0) {
+	if (old_ms->dl_tbf() && !old_ms->dl_tbf()->timers_pending(T_MAX)) {
 		if (old_ms->dl_tbf() == this) {
 			LOGP(DRLCMAC, LOGL_ERROR,
 				"%s is referred by the old MS "
@@ -393,7 +403,7 @@ gprs_rlcmac_ul_tbf *tbf_alloc_ul(struct gprs_rlcmac_bts *bts,
 	tbf->m_contention_resolution_done = 1;
 	tbf->set_state(GPRS_RLCMAC_ASSIGN);
 	tbf->state_flags |= (1 << GPRS_RLCMAC_FLAG_PACCH);
-	tbf_timer_start(tbf, 3169, bts->t3169, 0, "allocation (UL-TBF)");
+	tbf->t_start(T3169, bts->t3169, 0, "allocation (UL-TBF)", true);
 	tbf->update_ms(tlli, GPRS_RLCMAC_UL_TBF);
 	OSMO_ASSERT(tbf->ms());
 
@@ -462,6 +472,7 @@ void tbf_free(struct gprs_rlcmac_tbf *tbf)
 		     get_value_string(gprs_rlcmac_tbf_dl_ass_state_names,
 				      tbf->dl_ass_state));
 	tbf->stop_timer("freeing TBF");
+	tbf->stop_timers("freeing TBF");
 	/* TODO: Could/Should generate  bssgp_tx_llc_discarded */
 	tbf_unlink_pdch(tbf);
 	llist_del(&tbf->list());
@@ -547,9 +558,40 @@ void tbf_timer_start(struct gprs_rlcmac_tbf *tbf, unsigned int T,
 	osmo_timer_schedule(&tbf->timer, seconds, microseconds);
 }
 
-void gprs_rlcmac_tbf::stop_t3191()
+void gprs_rlcmac_tbf::t_stop(enum tbf_timers t, const char *reason)
 {
-	return stop_timer("T3191");
+	if (t >= T_MAX) {
+		LOGPTBF(this, LOGL_ERROR, "attempting to stop unknown timer %s [%s]\n",
+			get_value_string(tbf_timers_names, t), reason);
+	}
+
+	if (osmo_timer_pending(&T31[t])) {
+		LOGPTBF(this, LOGL_DEBUG, "stopping timer %s [%s]\n",
+			get_value_string(tbf_timers_names, t), reason);
+		osmo_timer_del(&T31[t]);
+	}
+}
+
+/* check if any of T31xx timer(s) are pending */
+bool gprs_rlcmac_tbf::timers_pending(enum tbf_timers t)
+{
+	uint8_t i;
+
+	if (t != T_MAX)
+		return osmo_timer_pending(&T31[t]);
+
+	for (i = T3169; i < T_MAX; i++)
+		if (osmo_timer_pending(&T31[i]))
+			return true;
+
+	return false;
+}
+
+void gprs_rlcmac_tbf::stop_timers(const char *reason)
+{
+	uint8_t i;
+	for (i = 0; i < T_MAX; i++)
+		t_stop((enum tbf_timers)i, reason);
 }
 
 void gprs_rlcmac_tbf::stop_timer(const char *reason)
@@ -561,6 +603,60 @@ void gprs_rlcmac_tbf::stop_timer(const char *reason)
 	}
 }
 
+static inline void tbf_timeout_free(struct gprs_rlcmac_tbf *tbf, enum tbf_timers t, bool run_diag)
+{
+	LOGPTBF(tbf, LOGL_NOTICE, "%s timeout expired, freeing TBF\n",
+		get_value_string(tbf_timers_names, t));
+
+	if (run_diag)
+		tbf->rlcmac_diag();
+
+	tbf_free(tbf);
+}
+
+#define T_CBACK(t, diag) static void cb_##t(void *_tbf) { tbf_timeout_free((struct gprs_rlcmac_tbf *)_tbf, t, diag); }
+
+T_CBACK(T3169, true)
+T_CBACK(T3191, true)
+T_CBACK(T3193, false)
+T_CBACK(T3195, true)
+
+void gprs_rlcmac_tbf::t_start(enum tbf_timers t, uint32_t sec, uint32_t microsec, const char *reason, bool force)
+{
+	if (t >= T_MAX) {
+		LOGPTBF(this, LOGL_ERROR, "attempting to start unknown timer %s [%s]\n",
+			get_value_string(tbf_timers_names, t), reason);
+	}
+
+	if (!force && osmo_timer_pending(&T31[t]))
+		return;
+
+	LOGPTBF(this, LOGL_DEBUG, "%sstarting timer %s [%s] with %u sec. %u microsec.\n",
+		osmo_timer_pending(&T31[t]) ? "re" : "", get_value_string(tbf_timers_names, t), reason, sec, microsec);
+
+	T31[t].data = this;
+
+	switch(t) {
+	case T3169:
+		T31[t].cb = cb_T3169;
+		break;
+	case T3191:
+		T31[t].cb = cb_T3191;
+		break;
+	case T3193:
+		T31[t].cb = cb_T3193;
+		break;
+	case T3195:
+		T31[t].cb = cb_T3195;
+		break;
+	default:
+		LOGPTBF(this, LOGL_ERROR, "attempting to set callback for unknown timer %s [%s]\n",
+			get_value_string(tbf_timers_names, t), reason);
+	}
+
+	osmo_timer_schedule(&T31[t], sec, microsec);
+}
+
 int gprs_rlcmac_tbf::check_polling(uint32_t fn, uint8_t ts,
 	uint32_t *poll_fn_, unsigned int *rrbp_)
 {
@@ -658,7 +754,7 @@ void gprs_rlcmac_tbf::poll_timeout()
 				     "- N3103 exceeded\n");
 				bts->pkt_ul_ack_nack_poll_failed();
 				ul_tbf->set_state(GPRS_RLCMAC_RELEASING);
-				tbf_timer_start(ul_tbf, 3169, ul_tbf->bts->bts_data()->t3169, 0, "MAX N3103 reached");
+				ul_tbf->t_start(T3169, ul_tbf->bts->bts_data()->t3169, 0, "MAX N3103 reached", false);
 				return;
 			}
 			/* reschedule UL ack */
@@ -680,7 +776,7 @@ void gprs_rlcmac_tbf::poll_timeout()
 		if (n3105 == bts_data()->n3105) {
 			LOGP(DRLCMAC, LOGL_NOTICE, "- N3105 exceeded\n");
 			set_state(GPRS_RLCMAC_RELEASING);
-			tbf_timer_start(this, 3195, bts_data()->t3195, 0, "MAX N3105 reached");
+			t_start(T3195, bts_data()->t3195, 0, "MAX N3105 reached", true);
 			bts->rlc_ass_failed();
 			bts->pua_poll_failed();
 			return;
@@ -702,7 +798,7 @@ void gprs_rlcmac_tbf::poll_timeout()
 		if (n3105 == bts->bts_data()->n3105) {
 			LOGP(DRLCMAC, LOGL_NOTICE, "- N3105 exceeded\n");
 			set_state(GPRS_RLCMAC_RELEASING);
-			tbf_timer_start(this, 3195, bts_data()->t3195, 0, "MAX N3105 reached");
+			t_start(T3195, bts_data()->t3195, 0, "MAX N3105 reached", true);
 			bts->rlc_ass_failed();
 			bts->pda_poll_failed();
 			return;
@@ -728,7 +824,7 @@ void gprs_rlcmac_tbf::poll_timeout()
 		if (dl_tbf->n3105 == dl_tbf->bts->bts_data()->n3105) {
 			LOGP(DRLCMAC, LOGL_NOTICE, "- N3105 exceeded\n");
 			dl_tbf->set_state(GPRS_RLCMAC_RELEASING);
-			tbf_timer_start(dl_tbf, 3195, dl_tbf->bts_data()->t3195, 0, "MAX N3105 reached");
+			dl_tbf->t_start(T3195, dl_tbf->bts_data()->t3195, 0, "MAX N3105 reached", true);
 			bts->pkt_dl_ack_nack_poll_failed();
 			bts->rlc_ack_failed();
 			return;
@@ -999,64 +1095,47 @@ void gprs_rlcmac_tbf::handle_timeout()
 {
 	LOGPTBF(this, LOGL_DEBUG, "timer %u expired.\n", T);
 
-	switch (T) {
-	case 0: /* assignment */
-		if ((state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))) {
-			if (state_is(GPRS_RLCMAC_ASSIGN)) {
-				LOGPTBF(this, LOGL_NOTICE,
-					"releasing due to PACCH assignment timeout.\n");
-				tbf_free(this);
-				return;
-			} else
-				LOGPTBF(this, LOGL_ERROR,
-					"Error: TBF is not in assign state\n");
-		}
-		if ((state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH))) {
-			gprs_rlcmac_dl_tbf *dl_tbf = as_dl_tbf(this);
-			dl_tbf->m_wait_confirm = 0;
-			if (dl_tbf->state_is(GPRS_RLCMAC_ASSIGN)) {
-				tbf_assign_control_ts(dl_tbf);
-
-				if (!dl_tbf->upgrade_to_multislot) {
-					/* change state to FLOW, so scheduler
-					 * will start transmission */
-					dl_tbf->set_state(GPRS_RLCMAC_FLOW);
-					break;
-				}
-
-				/* This tbf can be upgraded to use multiple DL
-				 * timeslots and now that there is already one
-				 * slot assigned send another DL assignment via
-				 * PDCH. */
-
-				/* keep to flags */
-				dl_tbf->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK;
-
-				dl_tbf->update();
-
-				dl_tbf->trigger_ass(dl_tbf);
-			} else
-				LOGPTBF(dl_tbf, LOGL_NOTICE,
-					"Continue flow after IMM.ASS confirm\n");
-		}
-		break;
-	case 3169:
-	case 3191:
-	case 3195:
-		LOGPTBF(this, LOGL_NOTICE, "T%d timeout during "
-			"transsmission\n", T);
-		rlcmac_diag();
-		/* fall through */
-	case 3193:
-		LOGP(DRLCMAC, LOGL_DEBUG,
-			"%s will be freed due to timeout\n", tbf_name(this));
-		/* free TBF */
-		tbf_free(this);
+	if (T) {
+		LOGPTBF(this, LOGL_ERROR, "%s timer expired in unknown mode: %u\n", T);
 		return;
-		break;
-	default:
-		LOGP(DRLCMAC, LOGL_ERROR,
-			"%s timer expired in unknown mode: %u\n", tbf_name(this), T);
+	}
+
+	/* assignment */
+	if ((state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))) {
+		if (state_is(GPRS_RLCMAC_ASSIGN)) {
+			LOGPTBF(this, LOGL_NOTICE, "releasing due to PACCH assignment timeout.\n");
+			tbf_free(this);
+			return;
+		} else
+			LOGPTBF(this, LOGL_ERROR, "Error: TBF is not in assign state\n");
+	}
+
+	if ((state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH))) {
+		gprs_rlcmac_dl_tbf *dl_tbf = as_dl_tbf(this);
+		dl_tbf->m_wait_confirm = 0;
+		if (dl_tbf->state_is(GPRS_RLCMAC_ASSIGN)) {
+			tbf_assign_control_ts(dl_tbf);
+
+			if (!dl_tbf->upgrade_to_multislot) {
+				/* change state to FLOW, so scheduler
+				 * will start transmission */
+				dl_tbf->set_state(GPRS_RLCMAC_FLOW);
+				return;
+			}
+
+			/* This tbf can be upgraded to use multiple DL
+			 * timeslots and now that there is already one
+			 * slot assigned send another DL assignment via
+			 * PDCH. */
+
+			/* keep to flags */
+			dl_tbf->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK;
+
+			dl_tbf->update();
+
+			dl_tbf->trigger_ass(dl_tbf);
+		} else
+			LOGPTBF(dl_tbf, LOGL_NOTICE, "Continue flow after IMM.ASS confirm\n");
 	}
 }