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gmm_fsm: Expect E_GMM_COMMON_PROC_INIT_REQ when in ST_GMM_COMMON_PROC_INIT 

Due to whatever errors, the MS may re-init the Common Procedure by
retransmitting a GPRS Attach Request while we are for instance aiting
for Identity to be resolved.

See this log:
MM(---/ffffffff) -> GMM ATTACH REQUEST MI(3903513414) type="GPRS attach"
GMM(gmm_fsm)[0x8136110]{Deregistered}: Allocated
GMM_ATTACH_REQ_FSM(gb_gmm_req)[0x81383c0]{Init}: Allocated
MM_STATE_Gb[0x8138ac0]{Idle}: Allocated
MM_STATE_Iu[0x8138bb0]{Detached}: Allocated
GMM(gmm_fsm)[0x8136110]{Deregistered}: Received Event E_GMM_COMMON_PROC_INIT_REQ
GMM(gmm_fsm)[0x8136110]{Deregistered}: state_chg to CommonProcedureInitiated
GMM_ATTACH_REQ_FSM(gb_gmm_req)[0x81383c0]{Init}: Received Event E_ATTACH_REQ_RECV
GMM_ATTACH_REQ_FSM(gb_gmm_req)[0x81383c0]{Init}: state_chg to CheckIdentity
MM(/fba673a2) <- GPRS IDENTITY REQUEST: mi_type=IMEI
UE(0x2){001-01-10422-99} Received GSM 04.08 message type 0x16, but no MM context available
GMM_ATTACH_REQ_FSM(gb_gmm_req)[0x81383c0]{CheckIdentity}: Timeout of T3370
MM(/fba673a2) <- GPRS IDENTITY REQUEST: mi_type=IMEI
[Failure to handle GSM48_MT_GMM_ID_RESP and subsequent retransmission of GPRS IDENTITY REQUEST happens a couple times here]
MM(---/ffffffff) -> GMM ATTACH REQUEST MI(3903513414) type="GPRS attach"
GMM(gmm_fsm)[0x8136110]{CommonProcedureInitiated}: Received Event E_GMM_COMMON_PROC_INIT_REQ
GMM(gmm_fsm)[0x8136110]{CommonProcedureInitiated}: Event E_GMM_COMMON_PROC_INIT_REQ not permitted
GMM_ATTACH_REQ_FSM(gb_gmm_req)[0x81383c0]{CheckIdentity}: Received Event E_ATTACH_REQ_RECV
[Here IDENTITY REQUEST is sent again, and this time MS answers ID RESPONSE back and goes forward]

Related: SYS#5389
Change-Id: I93d7d6bc694c84223a11d075d24c234b82b73389
This commit is contained in:
Pau Espin 2021-03-25 16:57:22 +01:00
parent ce0a0e9beb
commit c26072a77f
1 changed files with 6 additions and 1 deletions
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7
src/sgsn/gprs_gmm_fsm.c
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@ -57,6 +57,10 @@ static void st_gmm_deregistered(struct osmo_fsm_inst *fi, uint32_t event, void *
static void st_gmm_common_proc_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch(event) {
case E_GMM_COMMON_PROC_INIT_REQ:
/* MS may retransmit GPRS Attach Request if for some reason
* CommonProcedure didn't go forward correctly */
break;
/* TODO: events not used
case E_GMM_LOWER_LAYER_FAILED:
case E_GMM_COMMON_PROC_FAILED:
@ -126,7 +130,8 @@ static struct osmo_fsm_state gmm_fsm_states[] = {
/* X(E_GMM_LOWER_LAYER_FAILED) | */
/* X(E_GMM_COMMON_PROC_FAILED) | */
X(E_GMM_COMMON_PROC_SUCCESS) |
X(E_GMM_ATTACH_SUCCESS),
X(E_GMM_ATTACH_SUCCESS) |
X(E_GMM_COMMON_PROC_INIT_REQ),
.out_state_mask =
X(ST_GMM_DEREGISTERED) |
X(ST_GMM_REGISTERED_NORMAL),