Avoid using N3105 in UL TBFs

This counter is only used in DL TBFs as per TS 44.060.
section 13.4 "N3105":
"When the network after sending a RRBP field in the _downlink RLC data block_ ..."
(DL data blocks are only sent in DL TBFs).

section 8.1.2.1:
"If N3105 = N3105max, the network shall release the downlink TBF internally
and start timer T3195 for that TBF. When T3195 expires, the network may reuse
the TFI"

Change-Id: I4d4f4d4d3e6e0539ea8ec2395bed00d059b84e04

3 files changed, 15 insertions, 35 deletions

diff --git a/src/pdch.cpp b/src/pdch.cpp
index 2cee011d..f871d1de 100644
--- a/src/pdch.cpp
+++ b/src/pdch.cpp
@@ -391,8 +391,8 @@ void gprs_rlcmac_pdch::rcv_control_ack(Packet_Control_Acknowledgement_t *packet,
 		}
 		LOGPTBF(tbf, LOGL_DEBUG, "[DOWNLINK] UPLINK ASSIGNED\n");
 		pdch_ulc_release_fn(ulc, fn);
-		/* reset N3105 */
-		tbf->n_reset(N3105);
+		if (tbf_direction(tbf) == GPRS_RLCMAC_DL_TBF)
+			tbf->n_reset(N3105);
 		osmo_fsm_inst_dispatch(tbf->ul_ass_fsm.fi, TBF_UL_ASS_EV_RX_ASS_CTRL_ACK, NULL);
 
 		new_tbf = ms_ul_tbf(ms);
@@ -422,8 +422,8 @@ void gprs_rlcmac_pdch::rcv_control_ack(Packet_Control_Acknowledgement_t *packet,
 		}
 		LOGPTBF(tbf, LOGL_DEBUG, "[UPLINK] DOWNLINK ASSIGNED\n");
 		pdch_ulc_release_fn(ulc, fn);
-		/* reset N3105 */
-		tbf->n_reset(N3105);
+		if (tbf_direction(tbf) == GPRS_RLCMAC_DL_TBF)
+			tbf->n_reset(N3105);
 		osmo_fsm_inst_dispatch(tbf->dl_ass_fsm.fi, TBF_DL_ASS_EV_RX_ASS_CTRL_ACK, NULL);
 
 		new_tbf = ms_dl_tbf(ms);
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 47256f87..885c6029 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -316,6 +316,9 @@ void gprs_rlcmac_tbf::n_reset(enum tbf_counters n)
 	case N3103:
 		OSMO_ASSERT(direction == GPRS_RLCMAC_UL_TBF);
 		break;
+	case N3105:
+		OSMO_ASSERT(direction == GPRS_RLCMAC_DL_TBF);
+		break;
 	default:
 		break;
 	}
@@ -342,6 +345,7 @@ bool gprs_rlcmac_tbf::n_inc(enum tbf_counters n)
 		chk = bts->n3103;
 		break;
 	case N3105:
+		OSMO_ASSERT(direction == GPRS_RLCMAC_DL_TBF);
 		chk = bts->n3105;
 		break;
 	default:
@@ -513,7 +517,7 @@ void gprs_rlcmac_tbf::poll_timeout(struct gprs_rlcmac_pdch *pdch, uint32_t poll_
 		}
 		bts_do_rate_ctr_inc(bts, CTR_RLC_ASS_TIMEDOUT);
 		bts_do_rate_ctr_inc(bts, CTR_PUA_POLL_TIMEDOUT);
-		if (n_inc(N3105)) {
+		if (this->direction == GPRS_RLCMAC_DL_TBF && n_inc(N3105)) {
 			osmo_fsm_inst_dispatch(this->state_fi, TBF_EV_MAX_N3105, NULL);
 			bts_do_rate_ctr_inc(bts, CTR_RLC_ASS_FAILED);
 			bts_do_rate_ctr_inc(bts, CTR_PUA_POLL_FAILED);
@@ -532,7 +536,7 @@ void gprs_rlcmac_tbf::poll_timeout(struct gprs_rlcmac_pdch *pdch, uint32_t poll_
 		}
 		bts_do_rate_ctr_inc(bts, CTR_RLC_ASS_TIMEDOUT);
 		bts_do_rate_ctr_inc(bts, CTR_PDA_POLL_TIMEDOUT);
-		if (n_inc(N3105)) {
+		if (this->direction == GPRS_RLCMAC_DL_TBF && n_inc(N3105)) {
 			osmo_fsm_inst_dispatch(this->state_fi, TBF_EV_MAX_N3105, NULL);
 			bts_do_rate_ctr_inc(bts, CTR_RLC_ASS_FAILED);
 			bts_do_rate_ctr_inc(bts, CTR_PDA_POLL_FAILED);
diff --git a/src/tbf_ul_fsm.c b/src/tbf_ul_fsm.c
index 13dc9fba..231ccd23 100644
--- a/src/tbf_ul_fsm.c
+++ b/src/tbf_ul_fsm.c
@@ -152,12 +152,6 @@ static void st_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 		}
 		tbf_ul_fsm_state_chg(fi, TBF_ST_FLOW);
 		break;
-	case TBF_EV_MAX_N3105:
-		/* We are going to release, so abort any Pkt Ul Ass pending to be scheduled: */
-		osmo_fsm_inst_dispatch(tbf_ul_ass_fi(ctx->tbf), TBF_UL_ASS_EV_ABORT, NULL);
-		ctx->T_release = 3195;
-		tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING);
-		break;
 	default:
 		OSMO_ASSERT(0);
 	}
@@ -199,10 +193,6 @@ static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 		ctx->T_release = 3169;
 		tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING);
 		break;
-	case TBF_EV_MAX_N3105:
-		ctx->T_release = 3195;
-		tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING);
-		break;
 	default:
 		OSMO_ASSERT(0);
 	}
@@ -246,10 +236,6 @@ static void st_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 		ctx->T_release = 3169;
 		tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING);
 		break;
-	case TBF_EV_MAX_N3105:
-		ctx->T_release = 3195;
-		tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING);
-		break;
 	default:
 		OSMO_ASSERT(0);
 	}
@@ -278,11 +264,6 @@ static void st_releasing_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
 static void st_releasing(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case TBF_EV_MAX_N3105:
-		/* This may be received here if the TBF had several polls
-		 * allocated concurrently and several failed each increasing N3105
-		 * over MAX_N3015. We are already releasing, ignore.*/
-		break;
 	default:
 		OSMO_ASSERT(0);
 	}
@@ -320,8 +301,7 @@ static struct osmo_fsm_state tbf_ul_fsm_states[] = {
 		.in_event_mask =
 			X(TBF_EV_ASSIGN_ADD_CCCH) |
 			X(TBF_EV_ASSIGN_ADD_PACCH) |
-			X(TBF_EV_ASSIGN_ACK_PACCH) |
-			X(TBF_EV_MAX_N3105),
+			X(TBF_EV_ASSIGN_ACK_PACCH),
 		.out_state_mask =
 			X(TBF_ST_FLOW) |
 			X(TBF_ST_FINISHED),
@@ -334,8 +314,7 @@ static struct osmo_fsm_state tbf_ul_fsm_states[] = {
 			X(TBF_EV_FIRST_UL_DATA_RECVD) |
 			X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) |
 			X(TBF_EV_LAST_UL_DATA_RECVD) |
-			X(TBF_EV_MAX_N3101) |
-			X(TBF_EV_MAX_N3105),
+			X(TBF_EV_MAX_N3101),
 		.out_state_mask =
 			X(TBF_ST_ASSIGN) |
 			X(TBF_ST_FINISHED) |
@@ -347,18 +326,15 @@ static struct osmo_fsm_state tbf_ul_fsm_states[] = {
 		.in_event_mask =
 			X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) |
 			X(TBF_EV_FINAL_UL_ACK_CONFIRMED) |
-			X(TBF_EV_MAX_N3103) |
-			X(TBF_EV_MAX_N3105),
+			X(TBF_EV_MAX_N3103),
 		.out_state_mask =
 			X(TBF_ST_RELEASING),
 		.name = "FINISHED",
 		.action = st_finished,
 	},
 	[TBF_ST_RELEASING] = {
-		.in_event_mask =
-			X(TBF_EV_MAX_N3105),
-		.out_state_mask =
-			0,
+		.in_event_mask = 0,
+		.out_state_mask = 0,
 		.name = "RELEASING",
 		.action = st_releasing,
 		.onenter = st_releasing_on_enter,