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tbf_fsm: Introduce new event to act upon contention resolution success 

This is a preparation towards fixing MS not recreating a DL-TBF (being
assigned on CCCH) when MS starts an UL-TBF and finishes contention
resolution.

A counter is removed which was counting contention resolution (MS) on
the wrong place.

Change-Id: I8b9555864d3615ce0a024b641c67921f82273a8d
This commit is contained in:
Pau Espin 2022-10-28 19:06:45 +02:00
parent 677bebbe5c
commit f38a47ee01
5 changed files with 22 additions and 9 deletions
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13
src/tbf_fsm.c
View File

@ -45,6 +45,7 @@ const struct value_string tbf_fsm_event_names[] = {
{ TBF_EV_ASSIGN_READY_CCCH, "ASSIGN_READY_CCCH" },
{ TBF_EV_ASSIGN_PCUIF_CNF, "ASSIGN_PCUIF_CNF" },
{ TBF_EV_FIRST_UL_DATA_RECVD, "FIRST_UL_DATA_RECVD" },
{ TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS, "CONTENTION_RESOLUTION_MS_SUCCESS" },
{ TBF_EV_DL_ACKNACK_MISS, "DL_ACKNACK_MISS" },
{ TBF_EV_LAST_DL_DATA_SENT, "LAST_DL_DATA_SENT" },
{ TBF_EV_LAST_UL_DATA_RECVD, "LAST_UL_DATA_RECVD" },
@ -230,6 +231,10 @@ static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data)
dl_tbf = NULL;
}
break;
case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS:
OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF);
ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf));
break;
case TBF_EV_DL_ACKNACK_MISS:
OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF);
/* DL TBF: we missed a DL ACK/NACK. If we started assignment
@ -279,6 +284,12 @@ static void st_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data)
bool new_ul_tbf_requested;
switch (event) {
case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS:
OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF);
/* UL TBF: If MS only sends 1 RLCMAC UL block, it can be that we
* end up in FINISHED state before sending the first UL ACK/NACK */
ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf));
break;
case TBF_EV_DL_ACKNACK_MISS:
OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF);
break;
@ -480,6 +491,7 @@ static struct osmo_fsm_state tbf_fsm_states[] = {
[TBF_ST_FLOW] = {
.in_event_mask =
X(TBF_EV_FIRST_UL_DATA_RECVD) |
X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) |
X(TBF_EV_DL_ACKNACK_MISS) |
X(TBF_EV_LAST_DL_DATA_SENT) |
X(TBF_EV_LAST_UL_DATA_RECVD) |
@ -496,6 +508,7 @@ static struct osmo_fsm_state tbf_fsm_states[] = {
},
[TBF_ST_FINISHED] = {
.in_event_mask =
X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) |
X(TBF_EV_DL_ACKNACK_MISS) |
X(TBF_EV_FINAL_ACK_RECVD) |
X(TBF_EV_FINAL_UL_ACK_CONFIRMED) |

1
src/tbf_fsm.h
View File

@ -29,6 +29,7 @@ enum tbf_fsm_event {
TBF_EV_ASSIGN_READY_CCCH, /* TBF Start Time timer triggered */
TBF_EV_ASSIGN_PCUIF_CNF, /* Transmission of IMM.ASS for DL TBF to the MS confirmed by BTS over PCUIF */
TBF_EV_FIRST_UL_DATA_RECVD, /* UL TBF: Received first UL data from MS. Equals to Contention Resolution completed on the network side */
TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS, /* UL TBF: Contention resolution success at the mobile station side (first UL_ACK_NACK confirming TLLI is received at the MS) */
TBF_EV_DL_ACKNACK_MISS, /* DL TBF: We polled for DL ACK/NACK but we received none (POLL timeout) */
TBF_EV_LAST_DL_DATA_SENT, /* DL TBF sends RLCMAC block containing last DL avilable data buffered */
TBF_EV_LAST_UL_DATA_RECVD, /* UL TBF sends RLCMAC block containing last UL data (cv=0) */

12
src/tbf_ul.cpp
View File

@ -257,6 +257,7 @@ int gprs_rlcmac_ul_tbf::assemble_forward_llc(const gprs_rlc_data *_data)
return 0;
}
/* 3GPP TS 44.060 sec 7a.2.1 Contention Resolution */
void gprs_rlcmac_ul_tbf::contention_resolution_start()
{
/* 3GPP TS 44.018 sec 11.1.2 Timers on the network side: "This timer is
@ -274,20 +275,17 @@ void gprs_rlcmac_ul_tbf::contention_resolution_start()
}
void gprs_rlcmac_ul_tbf::contention_resolution_success()
{
if (m_contention_resolution_done)
return;
/* now we must set this flag, so we are allowed to assign downlink
* TBF on PACCH. it is only allowed when TLLI is acknowledged
* (3GPP TS 44.060 sec 7.1.3.1). */
m_contention_resolution_done = true;
/* 3GPP TS 44.060 sec 7a.2.1 Contention Resolution */
/* 3GPP TS 44.018 3.5.2.1.4 Packet access completion: The one phase
packet access procedure is completed at a successful contention
resolution. The mobile station has entered the packet transfer mode.
Timer T3141 is stopped on the network side */
t_stop(T3141, "Contention resolution success (UL-TBF, CCCH)");
/* now we must set this flag, so we are allowed to assign downlink
* TBF on PACCH. it is only allowed when TLLI is acknowledged. */
m_contention_resolution_done = true;
bts_do_rate_ctr_inc(bts, CTR_IMMEDIATE_ASSIGN_UL_TBF_CONTENTION_RESOLUTION_SUCCESS);
}

4
src/tbf_ul_ack_fsm.c
View File

@ -89,8 +89,8 @@ static struct msgb *create_ul_ack_nack(const struct tbf_ul_ack_fsm_ctx *ctx,
* on the mobile station side when the mobile station receives a
* PACKET UPLINK ACK/NACK"
*/
if (ms_tlli(ms) != GSM_RESERVED_TMSI)
ul_tbf_contention_resolution_success(ctx->tbf);
if (ms_tlli(ms) != GSM_RESERVED_TMSI && !ul_tbf_contention_resolution_done(ctx->tbf))
osmo_fsm_inst_dispatch(tbf_state_fi(ul_tbf_as_tbf(ctx->tbf)), TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS, NULL);
if (final) {
tbf_set_polling(ul_tbf_as_tbf(tbf), new_poll_fn, d->ts, PDCH_ULC_POLL_UL_ACK);

1
tests/tbf/TbfTest.err
View File

@ -1912,6 +1912,7 @@ Got 'TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FINISHED)', TA=7
Got MS: TLLI = 0xf1223344, TA = 7
UL_ACK_TBF(UL-TFI_0){SCHED_UL_ACK}: Received Event CREATE_RLCMAC_MSG
PDCH(bts=0,trx=0,ts=7) POLL scheduled at FN 2654167 + 17 = 2654184
TBF(UL-TFI_0){FINISHED}: Received Event CONTENTION_RESOLUTION_MS_SUCCESS
TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FINISHED) stopping timer T3141 [Contention resolution success (UL-TBF, CCCH)]
TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FINISHED) Scheduled UL Acknowledgement polling on PACCH (FN=2654184, TS=7)
UL_ACK_TBF(UL-TFI_0){SCHED_UL_ACK}: state_chg to WAIT_ACK