ul_tbf: Clean up handle_tbf_reject()

Document the function, make it look similar to usual TBF creation path
tbf_alloc_ul()->tbf_alloc_ul_tbf->tbf::setup(), which it mimics with
some differences.
Get rid of unneeded stuff like creating MS and settings its TLLI (that's
already done in only caller of the function). There's no need for
calling update_ms() either.

Change-Id: I61df2e4f0f0df1f8db941741a2d35a2319252c5e

src/pdch.cpp

@@ -685,8 +685,7 @@ void gprs_rlcmac_pdch::rcv_resource_request(Packet_Resource_Request_t *request,
 
 		ul_tbf = tbf_alloc_ul(bts(), ms, trx_no(), tlli);
 		if (!ul_tbf) {
-			handle_tbf_reject(bts(), ms, tlli,
-				trx_no(), ts_no);
+			handle_tbf_reject(bts(), ms, trx_no(), ts_no);
 			goto return_unref;
 		}
 

src/tbf_ul.cpp

@@ -96,6 +96,7 @@ static int ul_tbf_dtor(struct gprs_rlcmac_ul_tbf *tbf)
 	return 0;
 }
 
+/* Generic function to alloc a UL TBF, later configured to be assigned either over CCCH or PACCH */
 struct gprs_rlcmac_ul_tbf *tbf_alloc_ul_tbf(struct gprs_rlcmac_bts *bts, GprsMs *ms, int8_t use_trx, bool single_slot)
 {
 	struct gprs_rlcmac_ul_tbf *tbf;
@@ -139,19 +140,16 @@ struct gprs_rlcmac_ul_tbf *tbf_alloc_ul_tbf(struct gprs_rlcmac_bts *bts, GprsMs
 	return tbf;
 }
 
-
+/* Alloc a UL TBF to be assigned over PACCH */
 gprs_rlcmac_ul_tbf *tbf_alloc_ul(struct gprs_rlcmac_bts *bts, GprsMs *ms, int8_t use_trx,
 				 uint32_t tlli)
 {
 	struct gprs_rlcmac_ul_tbf *tbf;
 
-/* FIXME: Copy and paste with tbf_new_dl_assignment */
-	/* create new TBF, use same TRX as DL TBF */
-	/* use multislot class of downlink TBF */
 	tbf = tbf_alloc_ul_tbf(bts, ms, use_trx, false);
 	if (!tbf) {
 		LOGPMS(ms, DTBF, LOGL_NOTICE, "No PDCH resource\n");
-		/* FIXME: send reject */
+		/* Caller will most probably send a Imm Ass Reject after return */
 		return NULL;
 	}
 	tbf->m_contention_resolution_done = 1;
@@ -162,30 +160,23 @@ gprs_rlcmac_ul_tbf *tbf_alloc_ul(struct gprs_rlcmac_bts *bts, GprsMs *ms, int8_t
 	return tbf;
 }
 
+/* Create a temporary dummy TBF to Tx a ImmAssReject if allocating a new one during
+ * packet resource Request failed. This is similar as tbf_alloc_ul() but without
+ * calling tbf->setup() (in charge of TFI/USF allocation), and reusing resources
+ * from Packet Resource Request we received. See TS 44.060 sec 7.1.3.2.1  */
 struct gprs_rlcmac_ul_tbf *handle_tbf_reject(struct gprs_rlcmac_bts *bts,
-			GprsMs *ms, uint32_t tlli, uint8_t trx_no, uint8_t ts)
+			GprsMs *ms, uint8_t trx_no, uint8_t ts)
 {
 	struct gprs_rlcmac_ul_tbf *ul_tbf = NULL;
 	struct gprs_rlcmac_trx *trx = &bts->trx[trx_no];
-
-	if (!ms)
-		ms = bts_alloc_ms(bts, 0, 0);
-	ms_set_tlli(ms, tlli);
+	OSMO_ASSERT(ms);
 
 	ul_tbf = talloc(tall_pcu_ctx, struct gprs_rlcmac_ul_tbf);
 	if (!ul_tbf)
 		return ul_tbf;
-
 	talloc_set_destructor(ul_tbf, ul_tbf_dtor);
 	new (ul_tbf) gprs_rlcmac_ul_tbf(bts, ms);
 
-	llist_add(tbf_bts_list((struct gprs_rlcmac_tbf *)ul_tbf), &bts->ul_tbfs);
-	bts_do_rate_ctr_inc(ul_tbf->bts, CTR_TBF_UL_ALLOCATED);
-	TBF_SET_ASS_ON(ul_tbf, GPRS_RLCMAC_FLAG_PACCH, false);
-
-	ms_attach_tbf(ms, ul_tbf);
-	ul_tbf->update_ms(tlli, GPRS_RLCMAC_UL_TBF);
-	TBF_SET_ASS_STATE_UL(ul_tbf, GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ);
 	ul_tbf->control_ts = ts;
 	ul_tbf->trx = trx;
 	ul_tbf->m_ctrs = rate_ctr_group_alloc(ul_tbf, &tbf_ctrg_desc, next_tbf_ctr_group_id++);
@@ -201,6 +192,12 @@ struct gprs_rlcmac_ul_tbf *handle_tbf_reject(struct gprs_rlcmac_bts *bts,
 		return NULL;
 	}
 
+	ms_attach_tbf(ms, ul_tbf);
+	llist_add(tbf_bts_list((struct gprs_rlcmac_tbf *)ul_tbf), &bts->ul_tbfs);
+	bts_do_rate_ctr_inc(ul_tbf->bts, CTR_TBF_UL_ALLOCATED);
+	TBF_SET_ASS_ON(ul_tbf, GPRS_RLCMAC_FLAG_PACCH, false);
+	TBF_SET_ASS_STATE_UL(ul_tbf, GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ);
+
 	return ul_tbf;
 }
 

src/tbf_ul.h

@@ -121,7 +121,7 @@ struct gprs_rlcmac_ul_tbf *tbf_alloc_ul_tbf(struct gprs_rlcmac_bts *bts, GprsMs
 struct gprs_rlcmac_ul_tbf *tbf_alloc_ul(struct gprs_rlcmac_bts *bts, GprsMs *ms,
 					int8_t use_trx, uint32_t tlli);
 struct gprs_rlcmac_ul_tbf *handle_tbf_reject(struct gprs_rlcmac_bts *bts,
-	GprsMs *ms, uint32_t tlli, uint8_t trx_no, uint8_t ts_no);
+	GprsMs *ms, uint8_t trx_no, uint8_t ts_no);
 
 #else /* ifdef __cplusplus */
 struct gprs_rlcmac_ul_tbf;

tests/tbf/TbfTest.cpp

@@ -3160,7 +3160,8 @@ static void test_packet_access_rej_prr_no_other_tbfs()
 	int ts_no = 7;
 	uint8_t trx_no = 0;
 	uint32_t tlli = 0xffeeddcc;
-	struct gprs_rlcmac_ul_tbf *ul_tbf = NULL;
+	struct gprs_rlcmac_ul_tbf *ul_tbf;
+	struct GprsMs *ms;
 
 	fprintf(stderr, "=== start %s ===\n", __func__);
 
@@ -3168,8 +3169,9 @@ static void test_packet_access_rej_prr_no_other_tbfs()
 
 	int rc = 0;
 
-	ul_tbf = handle_tbf_reject(bts, NULL, tlli,
-				trx_no, ts_no);
+	ms = bts_alloc_ms(bts, 0, 0);
+	ms_set_tlli(ms, tlli);
+	ul_tbf = handle_tbf_reject(bts, ms, trx_no, ts_no);
 
 	OSMO_ASSERT(ul_tbf != 0);
 

tests/tbf/TbfTest.err

@@ -7956,8 +7956,8 @@ MS(TLLI=0xffeeddd3, IMSI=, TA=7, 11/11,) Allocating UL TBF
 [UL] algo A <multi> (suggested TRX: 0): failed to allocate a TS, no USF available
 TBF(TFI=0 TLLI=0xffeeddd3 DIR=UL STATE=NULL EGPRS) Timeslot Allocation failed: trx = 0, single_slot = 0
 MS(TLLI=0xffeeddd3, IMSI=, TA=7, 11/11,) No PDCH resource
+MS(TLLI=0xffeeddd3, IMSI=, TA=7, 11/11,) Attaching UL TBF: TBF(TFI=0 TLLI=0xffeeddd3 DIR=UL STATE=NULL)
 TBF(TFI=0 TLLI=0xffeeddd3 DIR=UL STATE=NULL) changes state from NULL to ASSIGN
-MS(TLLI=0xffeeddd3, IMSI=, TA=7, 11/11,) Attaching UL TBF: TBF(TFI=0 TLLI=0xffeeddd3 DIR=UL STATE=ASSIGN)
 TBF(TFI=0 TLLI=0xffeeddd3 DIR=UL STATE=ASSIGN) changes UL ASS state from GPRS_RLCMAC_UL_ASS_NONE to GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ
 PDCH(bts=0,trx=0,ts=7) Expiring FN=82 but previous FN=2654231 is still reserved!
 PDCH(bts=0,trx=0,ts=7) Timeout for registered POLL (FN=2654231): TBF(TFI=6 TLLI=0xffeeddd2 DIR=UL STATE=ASSIGN EGPRS)
@@ -7974,8 +7974,8 @@ PDCH(bts=0,trx=0,ts=7) FN=2654218 Scheduling control message at RTS for TBF(TFI=
 === start test_packet_access_rej_prr_no_other_tbfs ===
 Creating MS object, TLLI = 0xffffffff
 Modifying MS object, UL TLLI: 0xffffffff -> 0xffeeddcc, not yet confirmed
+MS(TLLI=0xffeeddcc, IMSI=, TA=220, 0/0,) Attaching UL TBF: TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=NULL)
 TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=NULL) changes state from NULL to ASSIGN
-MS(TLLI=0xffeeddcc, IMSI=, TA=220, 0/0,) Attaching UL TBF: TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=ASSIGN)
 TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=ASSIGN) changes UL ASS state from GPRS_RLCMAC_UL_ASS_NONE to GPRS_RLCMAC_UL_ASS_SEND_ASS_REJ
 TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=ASSIGN) starting timer T0 [reject (PACCH)] with 0 sec. 2000 microsec, cur_fn=2654167
 PDCH(bts=0,trx=0,ts=7) FN=2654218 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xffeeddcc DIR=UL STATE=ASSIGN)