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[smf] state machine improvements (#76)
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@spencersevilla
spencersevilla committed Jan 24, 2024
1 parent dbd0870 commit 5287845
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Showing 4 changed files with 150 additions and 58 deletions.
5 changes: 5 additions & 0 deletions src/smf/context.h
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Original file line number Diff line number Diff line change
Expand Up @@ -434,6 +434,11 @@ typedef struct smf_sess_s {

bool active;

bool teardown_pfcp;
bool teardown_gx;
bool teardown_gy;
bool teardown_gtp;

smf_ue_t *smf_ue;

bool n1_released;
Expand Down
199 changes: 144 additions & 55 deletions src/smf/gsm-sm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -137,12 +137,15 @@ static bool send_ccr_termination_req_gx_gy_s6b(smf_sess_t *sess, smf_event_t *e)

if (use_gy == -1) {
ogs_error("No Gy Diameter Peer");
/* TODO: drop Gx connection here,
* possibly move to another "releasing" state! */
uint8_t gtp_cause = (e->gtp_xact->gtp_version == 1) ?
OGS_GTP1_CAUSE_NO_RESOURCES_AVAILABLE :
OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
send_gtp_delete_err_msg(sess, e->gtp_xact, gtp_cause);
sess->teardown_gtp = false;

sess->teardown_gx = false;
sess->teardown_gy = false;

return false;
}

Expand All @@ -152,14 +155,15 @@ static bool send_ccr_termination_req_gx_gy_s6b(smf_sess_t *sess, smf_event_t *e)
OGS_DIAM_TERMINATION_CAUSE_DIAMETER_LOGOUT);
}

sess->sm_data.gx_ccr_term_in_flight = true;
sess->timer_gx_cca = ogs_timer_add(ogs_app()->timer_mgr, smf_timer_gx_no_cca, e);
ogs_assert(sess->timer_gx_cca);
ogs_timer_start(sess->timer_gx_cca, ogs_local_conf()->time.message.diameter_timeout);
smf_gx_send_ccr(sess, e->gtp_xact,
OGS_DIAM_GX_CC_REQUEST_TYPE_TERMINATION_REQUEST);
if (sess->teardown_gx) {
sess->timer_gx_cca = ogs_timer_add(ogs_app()->timer_mgr, smf_timer_gx_no_cca, e);
ogs_assert(sess->timer_gx_cca);
ogs_timer_start(sess->timer_gx_cca, ogs_local_conf()->time.message.diameter_timeout);
smf_gx_send_ccr(sess, e->gtp_xact,
OGS_DIAM_GX_CC_REQUEST_TYPE_TERMINATION_REQUEST);
}

if (use_gy == 1) {
if (sess->teardown_gy && use_gy == 1) {
/* Gy is available,
* set up session for the bearer before accepting it towards the UE */
sess->sm_data.gy_ccr_term_in_flight = true;
Expand All @@ -170,6 +174,10 @@ static bool send_ccr_termination_req_gx_gy_s6b(smf_sess_t *sess, smf_event_t *e)
smf_gy_send_ccr(sess, e->gtp_xact,
OGS_DIAM_GY_CC_REQUEST_TYPE_TERMINATION_REQUEST);
}

sess->teardown_gx = false;
sess->teardown_gy = false;

return true;
}

Expand Down Expand Up @@ -220,10 +228,17 @@ void smf_gsm_state_initial(ogs_fsm_t *s, smf_event_t *e)
&e->gtp1_message->create_pdp_context_request);
if (gtp1_cause != OGS_GTP1_CAUSE_REQUEST_ACCEPTED) {
send_gtp_create_err_msg(sess, e->gtp_xact, gtp1_cause);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
return;
}
if (send_ccr_init_req_gx_gy(sess, e) == true)
OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_initial);

if (send_ccr_init_req_gx_gy(sess, e) == false) {
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
return;
}

OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_initial);
return;
}
break;

Expand All @@ -238,12 +253,17 @@ void smf_gsm_state_initial(ogs_fsm_t *s, smf_event_t *e)
&e->gtp2_message->create_session_request);
if (gtp2_cause != OGS_GTP2_CAUSE_REQUEST_ACCEPTED) {
send_gtp_create_err_msg(sess, e->gtp_xact, gtp2_cause);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
return;
}

switch (sess->gtp_rat_type) {
case OGS_GTP2_RAT_TYPE_EUTRAN:
if (send_ccr_init_req_gx_gy(sess, e) == true)
OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_initial);
if (send_ccr_init_req_gx_gy(sess, e) == false) {
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
break;
}
OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_initial);
break;
case OGS_GTP2_RAT_TYPE_WLAN:
sess->timer_gx_cca = ogs_timer_add(ogs_app()->timer_mgr,
Expand Down Expand Up @@ -379,8 +399,8 @@ void smf_gsm_state_wait_epc_auth_initial(ogs_fsm_t *s, smf_event_t *e)
ogs_timer_stop(sess->timer_gx_cca);
ogs_timer_delete(sess->timer_gx_cca);
sess->timer_gx_cca = NULL;

sess->sm_data.gx_cca_init_err = diam_err;
sess->teardown_gx = true;
goto test_can_proceed;
}
break;
Expand All @@ -404,6 +424,7 @@ void smf_gsm_state_wait_epc_auth_initial(ogs_fsm_t *s, smf_event_t *e)
sess->timer_gy_cca = NULL;

sess->sm_data.gy_cca_init_err = diam_err;
sess->teardown_gy = true;
goto test_can_proceed;
}
break;
Expand Down Expand Up @@ -438,22 +459,22 @@ void smf_gsm_state_wait_epc_auth_initial(ogs_fsm_t *s, smf_event_t *e)
if (!sess->sm_data.gx_ccr_init_in_flight &&
!sess->sm_data.gy_ccr_init_in_flight) {
diam_err = ER_DIAMETER_SUCCESS;
if (sess->sm_data.gx_cca_init_err != ER_DIAMETER_SUCCESS)
if (sess->sm_data.gx_cca_init_err != ER_DIAMETER_SUCCESS) {
diam_err = sess->sm_data.gx_cca_init_err;
if (sess->sm_data.gy_cca_init_err != ER_DIAMETER_SUCCESS)
sess->teardown_gx = false;
}
if (sess->sm_data.gy_cca_init_err != ER_DIAMETER_SUCCESS) {
diam_err = sess->sm_data.gy_cca_init_err;
sess->teardown_gy = false;
}

if (diam_err == ER_DIAMETER_SUCCESS) {
OGS_FSM_TRAN(s, smf_gsm_state_wait_pfcp_establishment);
ogs_assert(OGS_OK ==
smf_epc_pfcp_send_session_establishment_request(
sess, e->gtp_xact, 0));
} else {
/* FIXME: tear down Gx/Gy session
* if its sm_data.*init_err == ER_DIAMETER_SUCCESS */
uint8_t gtp_cause = gtp_cause_from_diameter(
e->gtp_xact->gtp_version, diam_err, NULL);
send_gtp_create_err_msg(sess, e->gtp_xact, gtp_cause);
OGS_FSM_TRAN(s, &smf_gsm_state_teardown);
}
}
}
Expand Down Expand Up @@ -625,6 +646,15 @@ void smf_gsm_state_wait_pfcp_establishment(ogs_fsm_t *s, smf_event_t *e)

switch (e->h.id) {
case OGS_FSM_ENTRY_SIG:
if (sess->epc) {
/* EPC */
ogs_assert(OGS_OK ==
smf_epc_pfcp_send_session_establishment_request(sess, e->gtp_xact, 0));
} else {
/* 5GC */
ogs_assert(OGS_OK ==
smf_5gc_pfcp_send_session_establishment_request(sess, 0));
}
break;

case SMF_EVT_N4_MESSAGE:
Expand All @@ -643,14 +673,16 @@ void smf_gsm_state_wait_pfcp_establishment(ogs_fsm_t *s, smf_event_t *e)
sess, pfcp_xact,
&pfcp_message->pfcp_session_establishment_response);
if (pfcp_cause != OGS_PFCP_CAUSE_REQUEST_ACCEPTED) {
/* FIXME: tear down Gy and Gx */
gtp_cause = gtp_cause_from_pfcp(
pfcp_cause, gtp_xact->gtp_version);
send_gtp_create_err_msg(sess, e->gtp_xact, gtp_cause);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
return;
}

gtp_xact = pfcp_xact->assoc_xact;
sess->teardown_pfcp = true;
sess->teardown_gtp = true;

if (gtp_xact) {
switch (gtp_xact->gtp_version) {
case 1:
Expand Down Expand Up @@ -696,6 +728,9 @@ void smf_gsm_state_wait_pfcp_establishment(ogs_fsm_t *s, smf_event_t *e)
OGS_FSM_TRAN(s, smf_gsm_state_5gc_n1_n2_reject);
return;
}

sess->teardown_pfcp = true;

memset(&param, 0, sizeof(param));
param.state = SMF_UE_REQUESTED_PDU_SESSION_ESTABLISHMENT;
param.n1smbuf =
Expand Down Expand Up @@ -733,6 +768,7 @@ void smf_gsm_state_wait_pfcp_establishment(ogs_fsm_t *s, smf_event_t *e)
OGS_GTP1_CAUSE_NETWORK_FAILURE :
OGS_GTP2_CAUSE_TIMED_OUT_REQUEST;
send_gtp_create_err_msg(sess, gtp_xact, gtp_cause);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
} else {
OGS_FSM_TRAN(s, smf_gsm_state_5gc_n1_n2_reject);
}
Expand Down Expand Up @@ -807,7 +843,7 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
OGS_GTP1_DELETE_PDP_CONTEXT_RESPONSE_TYPE, gtp1_cause);
return;
}
OGS_FSM_TRAN(s, smf_gsm_state_wait_pfcp_deletion);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
}
break;

Expand All @@ -825,14 +861,14 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
OGS_GTP2_DELETE_SESSION_RESPONSE_TYPE, gtp2_cause);
return;
}
OGS_FSM_TRAN(s, smf_gsm_state_wait_pfcp_deletion);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
break;
case OGS_GTP2_DELETE_BEARER_RESPONSE_TYPE:
release = smf_s5c_handle_delete_bearer_response(
sess, e->gtp_xact, &e->gtp2_message->delete_bearer_response);
if (release) {
e->gtp_xact = NULL;
OGS_FSM_TRAN(s, smf_gsm_state_wait_pfcp_deletion);
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
}
break;
case OGS_GTP2_CREATE_SESSION_REQUEST_TYPE:
Expand Down Expand Up @@ -1037,7 +1073,7 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
smf_namf_comm_send_n1_n2_message_transfer(sess, &param);
} else {
OGS_FSM_TRAN(&sess->sm,
&smf_gsm_state_wait_pfcp_deletion);
&smf_gsm_state_teardown);
}
break;

Expand Down Expand Up @@ -1312,6 +1348,63 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
}
}

void smf_gsm_state_teardown(ogs_fsm_t *s, smf_event_t *e) {
smf_sess_t *sess = NULL;

ogs_assert(s);
ogs_assert(e);

smf_sm_debug(e);

sess = e->sess;
ogs_assert(sess);

switch (e->h.id) {
case OGS_FSM_ENTRY_SIG:
if (sess->teardown_pfcp) {
sess->teardown_pfcp = false;
OGS_FSM_TRAN(s, smf_gsm_state_wait_pfcp_deletion);
break;
}

if (sess->teardown_gx || sess->teardown_gy) {
// NOTE: we can't teardown gx/gy just yet because we
// cue off of them to decide which messages to send
OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_release);
break;
}

if (sess->teardown_gtp) {
sess->teardown_gtp = false;
if (e->gtp_xact) {
switch (e->gtp_xact->gtp_version) {
case 1:
ogs_assert(OGS_OK ==
smf_gtp1_send_delete_pdp_context_response(
sess, e->gtp_xact));
break;
case 2:
ogs_assert(OGS_OK ==
smf_gtp2_send_delete_session_response(
sess, e->gtp_xact));
break;
}
}
}

OGS_FSM_TRAN(s, smf_gsm_state_epc_session_will_release);
break;

case OGS_FSM_EXIT_SIG:
break;

default:
ogs_error("Unknown event %s", smf_event_get_name(e));
break;
}
}


void smf_gsm_state_wait_pfcp_deletion(ogs_fsm_t *s, smf_event_t *e)
{
int status;
Expand Down Expand Up @@ -1369,24 +1462,26 @@ void smf_gsm_state_wait_pfcp_deletion(ogs_fsm_t *s, smf_event_t *e)
switch (pfcp_message->h.type) {
case OGS_PFCP_SESSION_DELETION_RESPONSE_TYPE:
if (pfcp_xact->epc) {
/* LTE */
gtp_xact = pfcp_xact->assoc_xact;

pfcp_cause = smf_epc_n4_handle_session_deletion_response(
sess, pfcp_xact,
&pfcp_message->pfcp_session_deletion_response);

if (pfcp_cause != OGS_PFCP_CAUSE_REQUEST_ACCEPTED) {
/* FIXME: tear down Gy and Gx */
ogs_assert(gtp_xact);
gtp_cause = gtp_cause_from_pfcp(
pfcp_cause, gtp_xact->gtp_version);
send_gtp_delete_err_msg(sess, gtp_xact, gtp_cause);
break;
sess->teardown_gtp = false;
}

e->gtp_xact = gtp_xact;
if (send_ccr_termination_req_gx_gy_s6b(sess, e) == true)
OGS_FSM_TRAN(s, smf_gsm_state_wait_epc_auth_release);
/* else: free session? */
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
break;
} else {
/* 5GC */
int trigger;

stream = pfcp_xact->assoc_stream;
Expand Down Expand Up @@ -1493,6 +1588,8 @@ void smf_gsm_state_wait_pfcp_deletion(ogs_fsm_t *s, smf_event_t *e)
} else {
ogs_error("5GC Session Deletion timeout not written");
}
sess->teardown_gtp = false;
OGS_FSM_TRAN(s, smf_gsm_state_teardown);
break;

default:
Expand Down Expand Up @@ -1525,6 +1622,14 @@ void smf_gsm_state_wait_epc_auth_release(ogs_fsm_t *s, smf_event_t *e)
sess->sm_data.gx_cca_term_err = ER_DIAMETER_SUCCESS;
sess->sm_data.gy_cca_term_err = ER_DIAMETER_SUCCESS;
sess->sm_data.s6b_sta_err = ER_DIAMETER_SUCCESS;

if (send_ccr_termination_req_gx_gy_s6b(sess, e) == false) {
// we barfed and didn't send any messages
sess->teardown_gx = false;
sess->teardown_gy = false;
OGS_FSM_TRAN(s, &smf_gsm_state_teardown);
}

break;

case SMF_EVT_GN_MESSAGE:
Expand Down Expand Up @@ -1624,30 +1729,14 @@ void smf_gsm_state_wait_epc_auth_release(ogs_fsm_t *s, smf_event_t *e)
if (sess->sm_data.s6b_sta_err != ER_DIAMETER_SUCCESS)
diam_err = sess->sm_data.s6b_sta_err;

/* Initiated by peer request, let's answer: */
if (e->gtp_xact) {
if (diam_err == ER_DIAMETER_SUCCESS) {
/*
* 1. MME sends Delete Session Request to SGW/SMF.
* 2. SMF sends Delete Session Response to SGW/MME.
*/
switch (e->gtp_xact->gtp_version) {
case 1:
smf_gtp1_send_delete_pdp_context_response(
sess, e->gtp_xact);
break;
case 2:
smf_gtp2_send_delete_session_response(
sess, e->gtp_xact);
break;
}
} else {
uint8_t gtp_cause = gtp_cause_from_diameter(
e->gtp_xact->gtp_version, diam_err, NULL);
send_gtp_delete_err_msg(sess, e->gtp_xact, gtp_cause);
}
if (diam_err != ER_DIAMETER_SUCCESS) {
uint8_t gtp_cause = gtp_cause_from_diameter(
e->gtp_xact->gtp_version, diam_err, NULL);
send_gtp_delete_err_msg(sess, e->gtp_xact, gtp_cause);
sess->teardown_gtp = false;
}
OGS_FSM_TRAN(s, smf_gsm_state_epc_session_will_release);

OGS_FSM_TRAN(s, smf_gsm_state_teardown);
}
}

Expand Down
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