Move GPRS_RLCMAC_FLAG_DL_ACK from state_fsm to dl_tbf

That flag was still in state_fsm for historical reasons (refactoring
steps), but it's not really the best place for it, since it's really
specific to dl_tbf and to transmit of data and DL ACK/NACK not the
overall state of the TBF.

Change-Id: I12c28c1a52f363f2d17a8bc24bbdf379543fc7a6

5 files changed, 13 insertions, 5 deletions

diff --git a/src/tbf.cpp b/src/tbf.cpp
index 8981615f..279efcdf 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -885,7 +885,7 @@ const char* tbf_rlcmac_diag(const struct gprs_rlcmac_tbf *tbf)
 			OSMO_STRBUF_PRINTF(sb, "Assignment was on CCCH|");
 		if (dl_tbf->state_fsm.state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))
 			OSMO_STRBUF_PRINTF(sb, "Assignment was on PACCH|");
-		if (dl_tbf->state_fsm.state_flags & (1 << GPRS_RLCMAC_FLAG_DL_ACK))
+		if (dl_tbf->m_first_dl_ack_rcvd)
 			OSMO_STRBUF_PRINTF(sb, "Downlink ACK was received|");
 		else
 			OSMO_STRBUF_PRINTF(sb, "No downlink ACK received yet|");
diff --git a/src/tbf.h b/src/tbf.h
index 941e350a..124a2e6d 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -109,7 +109,6 @@ enum tbf_counters { /* TBF counters from 3GPP TS 44.060 §13.4 */
 
 #define GPRS_RLCMAC_FLAG_CCCH		0 /* assignment on CCCH */
 #define GPRS_RLCMAC_FLAG_PACCH		1 /* assignment on PACCH */
-#define GPRS_RLCMAC_FLAG_DL_ACK		2 /* DL TBF: At least one DL ACK/NACK was recieved since it was assigned */
 #define TBF_TFI_UNSET 0xff
 
 #define T_START(tbf, t, T, r, f) tbf->t_start(t, T, r, f, __FILE__, __LINE__)
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 170ed251..17d29348 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -164,6 +164,7 @@ gprs_rlcmac_dl_tbf::gprs_rlcmac_dl_tbf(struct gprs_rlcmac_bts *bts_, GprsMs *ms)
 	m_last_dl_poll_fn(-1),
 	m_last_dl_poll_ack_lost(false),
 	m_last_dl_drained_fn(-1),
+	m_first_dl_ack_rcvd(false),
 	m_dl_gprs_ctrs(NULL),
 	m_dl_egprs_ctrs(NULL)
 {
@@ -1080,7 +1081,7 @@ int gprs_rlcmac_dl_tbf::rcvd_dl_ack(bool final_ack, unsigned first_bsn,
 	int rc;
 	LOGPTBFDL(this, LOGL_DEBUG, "downlink acknowledge\n");
 
-	state_fsm.state_flags |= (1 << GPRS_RLCMAC_FLAG_DL_ACK);
+	m_first_dl_ack_rcvd = true;
 	m_last_dl_poll_ack_lost = false;
 
 	/* reset N3105 */
@@ -1114,6 +1115,11 @@ void dl_tbf_request_dl_ack(struct gprs_rlcmac_dl_tbf *dl_tbf) {
 	dl_tbf->request_dl_ack();
 }
 
+bool dl_tbf_first_dl_ack_rcvd(const struct gprs_rlcmac_dl_tbf *tbf)
+{
+	return tbf->m_first_dl_ack_rcvd;
+}
+
 /* Does this DL TBF require to poll the MS for DL ACK/NACK? */
 bool gprs_rlcmac_dl_tbf::need_poll_for_dl_ack_nack() const
 {
diff --git a/src/tbf_dl.h b/src/tbf_dl.h
index ec75e327..dabe9a90 100644
--- a/src/tbf_dl.h
+++ b/src/tbf_dl.h
@@ -75,6 +75,8 @@ struct gprs_rlcmac_dl_tbf : public gprs_rlcmac_tbf {
 	 * MS polled during DL ACK/NACK with RRBP set in "m_last_dl_poll_fn": */
 	bool m_last_dl_poll_ack_lost;
 	int32_t m_last_dl_drained_fn;
+	/* Whether we receive at least one PKT DL ACK/NACK from MS since this DL TBF was assigned: */
+	bool m_first_dl_ack_rcvd;
 
 	struct BandWidth {
 		struct timespec dl_bw_tv; /* timestamp for dl bw calculation */
@@ -156,6 +158,7 @@ void dl_tbf_apply_allocated_resources(struct gprs_rlcmac_dl_tbf *dl_tbf, const s
 void dl_tbf_trigger_ass_on_pacch(struct gprs_rlcmac_dl_tbf *tbf, struct gprs_rlcmac_tbf *old_tbf);
 void dl_tbf_trigger_ass_on_pch(struct gprs_rlcmac_dl_tbf *tbf);
 void dl_tbf_request_dl_ack(struct gprs_rlcmac_dl_tbf *tbf);
+bool dl_tbf_first_dl_ack_rcvd(const struct gprs_rlcmac_dl_tbf *tbf);
 int dl_tbf_upgrade_to_multislot(struct gprs_rlcmac_dl_tbf *tbf);
 
 static inline struct gprs_rlcmac_tbf *dl_tbf_as_tbf(struct gprs_rlcmac_dl_tbf *dl_tbf)
diff --git a/src/tbf_dl_fsm.c b/src/tbf_dl_fsm.c
index 6c3f4f16..ce9bee3c 100644
--- a/src/tbf_dl_fsm.c
+++ b/src/tbf_dl_fsm.c
@@ -208,8 +208,8 @@ static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 		 * don't even know if the MS successfully received the Imm Ass on
 		 * CCCH and hence is listening on PDCH. Let's better refrain
 		 * from continuing and start assignment on CCCH again */
-		if ((ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH))
-		     && !(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_DL_ACK))) {
+		if ((ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)) &&
+		    !dl_tbf_first_dl_ack_rcvd(ctx->dl_tbf)) {
 			struct GprsMs *ms = tbf_ms(ctx->tbf);
 			LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG,
 				  "Re-send downlink assignment on PCH (IMSI=%s)\n",