tbf: Add state WAIT_ASSIGN

Currently the state on the TBF is set to ASSIGN when it is created
and in general changed to FLOW when it is acknowledged by the MS. The
moment when the assignment is really transmitted to the MS (which can
take some time) is not reflected by the state. A TBF can considered
to be valid, when the assignment is received by the MS.

Add the state WAIT_ASSIGN that is entered when the assigment has been
send to the MS (more precisely: when the corresponding RTS has been
processed or the message has been sent to the BTS).

The TBF, its PDCH(s), and its TFI can be assumed to be valid, when the
TBF has a state of WAIT_ASSIGN or higher (assuming that the TBF
starting time has not been set, which is currently only done for SBA,
which are not associated with a TBF).

Note that due to queuing in the BTS there can still be a invalid
time period for immediate assignments, when the request is lingering
in the AGCH or PCH queues.

Sponsored-by: On-Waves ehf

3 files changed, 23 insertions, 9 deletions

diff --git a/src/bts.cpp b/src/bts.cpp
index 5cadda1b..715fb515 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -544,8 +544,11 @@ int BTS::rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta)
 		m_bts.trx[trx_no].arfcn, ts_no, tsc, usf, 0, sb_fn,
 		m_bts.alpha, m_bts.gamma, -1);
 
-	if (plen >= 0)
+	if (plen >= 0) {
 		pcu_l1if_tx_agch(immediate_assignment, plen);
+		if (tbf)
+			tbf->set_state(GPRS_RLCMAC_WAIT_ASSIGN);
+	}
 
 	bitvec_free(immediate_assignment);
 
@@ -603,8 +606,10 @@ void BTS::snd_dl_ass(gprs_rlcmac_tbf *tbf, uint8_t poll, const char *imsi)
 		(tbf->pdch[ts]->last_rts_fn + 21216) % 2715648, tbf->ta(),
 		tbf->trx->arfcn, ts, tbf->tsc(), 7, poll,
 		tbf->poll_fn, m_bts.alpha, m_bts.gamma, -1);
-	if (plen >= 0)
+	if (plen >= 0) {
 		pcu_l1if_tx_pch(immediate_assignment, plen, imsi);
+		tbf->set_state(GPRS_RLCMAC_WAIT_ASSIGN);
+	}
 	bitvec_free(immediate_assignment);
 }
 
diff --git a/src/tbf.cpp b/src/tbf.cpp
index c07f379e..69b9e3a0 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -394,6 +394,7 @@ int tbf_assign_control_ts(struct gprs_rlcmac_tbf *tbf)
 const char *gprs_rlcmac_tbf::tbf_state_name[] = {
 	"NULL",
 	"ASSIGN",
+	"WAIT ASSIGN",
 	"FLOW",
 	"FINISHED",
 	"WAIT RELEASE",
@@ -824,6 +825,12 @@ void gprs_rlcmac_tbf::handle_timeout()
 		if ((state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))) {
 			if (state_is(GPRS_RLCMAC_ASSIGN)) {
 				LOGP(DRLCMAC, LOGL_NOTICE, "%s releasing due to "
+					"PACCH assignment timeout (not yet sent).\n",
+					tbf_name(this));
+				tbf_free(this);
+				return;
+			} else if (state_is(GPRS_RLCMAC_WAIT_ASSIGN)) {
+				LOGP(DRLCMAC, LOGL_NOTICE, "%s releasing due to "
 					"PACCH assignment timeout.\n", tbf_name(this));
 				tbf_free(this);
 				return;
@@ -834,7 +841,7 @@ void gprs_rlcmac_tbf::handle_timeout()
 		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)) {
+			if (dl_tbf->state_is(GPRS_RLCMAC_WAIT_ASSIGN)) {
 				tbf_assign_control_ts(dl_tbf);
 
 				if (!dl_tbf->upgrade_to_multislot) {
@@ -995,6 +1002,8 @@ struct msgb *gprs_rlcmac_tbf::create_dl_ass(uint32_t fn, uint8_t ts)
 
 	if (poll_ass_dl) {
 		set_polling(new_poll_fn, ts);
+		if (new_dl_tbf->state_is(GPRS_RLCMAC_ASSIGN))
+			new_dl_tbf->set_state(GPRS_RLCMAC_WAIT_ASSIGN);
 		dl_ass_state = GPRS_RLCMAC_DL_ASS_WAIT_ACK;
 		LOGP(DRLCMACDL, LOGL_INFO,
 			"%s Scheduled DL Assignment polling on FN=%d, TS=%d\n",
@@ -1067,6 +1076,8 @@ struct msgb *gprs_rlcmac_tbf::create_ul_ass(uint32_t fn, uint8_t ts)
 
 	set_polling(new_poll_fn, ts);
 	ul_ass_state = GPRS_RLCMAC_UL_ASS_WAIT_ACK;
+	if (new_tbf->state_is(GPRS_RLCMAC_ASSIGN))
+		new_tbf->set_state(GPRS_RLCMAC_WAIT_ASSIGN);
 	LOGP(DRLCMACDL, LOGL_INFO,
 		"%s Scheduled UL Assignment polling on FN=%d, TS=%d\n",
 		name(), poll_fn, poll_ts);
diff --git a/src/tbf.h b/src/tbf.h
index d1b286cb..443f85fc 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -43,7 +43,8 @@ class GprsMs;
 
 enum gprs_rlcmac_tbf_state {
 	GPRS_RLCMAC_NULL = 0,	/* new created TBF */
-	GPRS_RLCMAC_ASSIGN,	/* wait for downlink assignment */
+	GPRS_RLCMAC_ASSIGN,     /* wait for DL transmission */
+	GPRS_RLCMAC_WAIT_ASSIGN,/* wait for confirmation */
 	GPRS_RLCMAC_FLOW,	/* RLC/MAC flow, resource needed */
 	GPRS_RLCMAC_FINISHED,	/* flow finished, wait for release */
 	GPRS_RLCMAC_WAIT_RELEASE,/* wait for release or restart of DL TBF */
@@ -230,7 +231,7 @@ protected:
 	int set_tlli_from_ul(uint32_t new_tlli);
 	void merge_and_clear_ms(GprsMs *old_ms);
 
-	static const char *tbf_state_name[6];
+	static const char *tbf_state_name[7];
 
 	class GprsMs *m_ms;
 
@@ -315,10 +316,7 @@ inline bool gprs_rlcmac_tbf::is_tfi_assigned() const
 {
 	/* The TBF is established or has been assigned by a IMM.ASS for
 	 * download */
-	return state > GPRS_RLCMAC_ASSIGN ||
-		(direction == GPRS_RLCMAC_DL_TBF &&
-		 state == GPRS_RLCMAC_ASSIGN &&
-		 (state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)));
+	return state > GPRS_RLCMAC_ASSIGN;
 }
 
 inline uint8_t gprs_rlcmac_tbf::tfi() const