Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
laforge has submitted this change and it was merged. (
https://gerrit.osmocom.org/c/osmo-bsc/+/15408 )
Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated
channel closed during WAIT_CC
..
bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed
during WAIT_CC
TTCN3 BSC_Tests.TC_ms_rel_ind_does_not_cause_bssmap_reset seems to
sometimes run into a race condition on the order of messages received by
osmo-bsc comming from MSC and BTS.
Usual (expected) scenario):
BTS->BSC EST IND
BSC->MSC CL3 Info
BSC<-MSC CC
BTS->BSC REL IND
BTS<-BSC DEACT SACCH
BSC->MSC ClearRequest
BSC<-MSC ClearCommand
BSC->MSC ClearComplete
BTS<-BSC RF Chan Release
BTS->BSC RF Chan Release ACK
Sometimes CC message and REL IND message are received swapped (because they
are sent by different components asynchronously in TTCN3).
As a result, osmo-bsc was failing to go into CLEARING state and was
unable to send the ClearRequest because CC was still not received.
So the idea is to stay in WAIT_CC until CC is received, then check if
the lchan was dropped and in that case go into clearing state.
Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b
---
M src/osmo-bsc/bsc_subscr_conn_fsm.c
1 file changed, 28 insertions(+), 5 deletions(-)
Approvals:
Jenkins Builder: Verified
laforge: Looks good to me, approved
diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c
b/src/osmo-bsc/bsc_subscr_conn_fsm.c
index f8784f9..60f035d 100644
--- a/src/osmo-bsc/bsc_subscr_conn_fsm.c
+++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c
@@ -332,8 +332,19 @@
struct gsm_subscriber_connection *conn = fi->priv;
switch (event) {
case GSCON_EV_A_CONN_CFM:
- /* MSC has confirmed the connection, we now change into the
-* active state and wait there for further operations */
+ /* MSC has confirmed the connection */
+
+ if (!conn->lchan) {
+ /* If associated lchan was released while we were
waiting for the
+ confirmed connection, then instead simply drop the
connection */
+ LOGPFSML(fi, LOGL_INFO,
+"Connection confirmed but lchan was dropped
previously, clearing conn\n");
+ osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, 999);
+ gscon_bssmap_clear(conn,
GSM0808_CAUSE_EQUIPMENT_FAILURE);
+ break;
+ }
+
+ /* We now change into the active state and wait there for
further operations. */
conn_fsm_state_chg(ST_ACTIVE);
/* if there's user payload, forward it just like EV_MT_DTAP */
/* FIXME: Question: if there's user payload attached to the CC,
forward it like EV_MT_DTAP? */
@@ -589,7 +600,7 @@
[ST_WAIT_CC] = {
.name = "WAIT_CC",
.in_event_mask = S(GSCON_EV_A_CONN_CFM),
- .out_state_mask = S(ST_ACTIVE),
+ .out_state_mask = S(ST_ACTIVE) | S(ST_CLEARING),
.action = gscon_fsm_wait_cc,
},
[ST_ACTIVE] = {
@@ -651,10 +662,22 @@
lchan_forget_conn(conn->lchan);
conn->lchan = NULL;
}
+ /* If the conn has no lchan anymore, it was released by the BTS and
needs to Clear towards MSC. */
if (!conn->lchan) {
- if (conn->fi->state != ST_CLEARING)
+ switch (conn->fi->state) {
+ case ST_WAIT_CC:
+ /* The SCCP connection was not yet confirmed by a CC,
the BSSAP is not fully established
+ yet so we cannot release it. First wait for the CC,
and release in gscon_fsm_wait_cc(). */
+ break;
+ default:
+ /* Ensure that the FSM is in ST_CLEARING. */
osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, 999);
- gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
+ /* fall thru, omit an error log if already in
ST_CLEARING */
+ case ST_CLEARING:
+ /* Request a Clear Command from the MSC. */
+ gscon_bssmap_clear(conn,
GSM0808_CAUSE_EQUIPMENT_FAILURE);
+ break;
+ }
}
}
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b
Gerrit-Change-Number: 15408
Gerrit-PatchSet: 4
Gerrit-Owner: pespin
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria
Gerrit-Reviewer: laforge
Gerrit-Reviewer: neels
Gerrit-Reviewer: pespin
Gerrit-MessageType: merged
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
laforge has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/15408 ) Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. Patch Set 4: Code-Review+2 -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 4 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria Gerrit-Reviewer: laforge Gerrit-Reviewer: neels Gerrit-Reviewer: pespin Gerrit-Comment-Date: Thu, 26 Sep 2019 19:32:03 + Gerrit-HasComments: No Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
laforge has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/15408 ) Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. Patch Set 4: Code-Review+1 -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 4 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria Gerrit-Reviewer: laforge Gerrit-Reviewer: neels Gerrit-Reviewer: pespin Gerrit-Comment-Date: Fri, 20 Sep 2019 15:23:18 + Gerrit-HasComments: No Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
Hello fixeria, neels, laforge, Jenkins Builder, I'd like you to reexamine a change. Please visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 to look at the new patch set (#4). Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC TTCN3 BSC_Tests.TC_ms_rel_ind_does_not_cause_bssmap_reset seems to sometimes run into a race condition on the order of messages received by osmo-bsc comming from MSC and BTS. Usual (expected) scenario): BTS->BSC EST IND BSC->MSC CL3 Info BSC<-MSC CC BTS->BSC REL IND BTS<-BSC DEACT SACCH BSC->MSC ClearRequest BSC<-MSC ClearCommand BSC->MSC ClearComplete BTS<-BSC RF Chan Release BTS->BSC RF Chan Release ACK Sometimes CC message and REL IND message are received swapped (because they are sent by different components asynchronously in TTCN3). As a result, osmo-bsc was failing to go into CLEARING state and was unable to send the ClearRequest because CC was still not received. So the idea is to stay in WAIT_CC until CC is received, then check if the lchan was dropped and in that case go into clearing state. Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b --- M src/osmo-bsc/bsc_subscr_conn_fsm.c 1 file changed, 28 insertions(+), 5 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/08/15408/4 -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 4 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria Gerrit-Reviewer: laforge Gerrit-Reviewer: neels Gerrit-Reviewer: pespin Gerrit-MessageType: newpatchset
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
neels has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/15408 ) Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. Patch Set 3: Code-Review+1 (2 comments) https://gerrit.osmocom.org/#/c/15408/3/src/osmo-bsc/bsc_subscr_conn_fsm.c File src/osmo-bsc/bsc_subscr_conn_fsm.c: https://gerrit.osmocom.org/#/c/15408/3/src/osmo-bsc/bsc_subscr_conn_fsm.c@340 PS3, Line 340: * simply drop the connection */ (use full line width) https://gerrit.osmocom.org/#/c/15408/3/src/osmo-bsc/bsc_subscr_conn_fsm.c@670 PS3, Line 670: yet so we cannot release it. First wait for the CC, and release in gscon_fsm_wait_cc(). */ (a '*' missing) -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 3 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria Gerrit-Reviewer: laforge Gerrit-Reviewer: neels Gerrit-Reviewer: pespin Gerrit-Comment-Date: Wed, 18 Sep 2019 00:44:08 + Gerrit-HasComments: Yes Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
Hello fixeria, neels, laforge, Jenkins Builder, I'd like you to reexamine a change. Please visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 to look at the new patch set (#3). Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC TTCN3 BSC_Tests.TC_ms_rel_ind_does_not_cause_bssmap_reset seems to sometimes run into a race condition on the order of messages received by osmo-bsc comming from MSC and BTS. Usual (expected) scenario): BTS->BSC EST IND BSC->MSC CL3 Info BSC<-MSC CC BTS->BSC REL IND BTS<-BSC DEACT SACCH BSC->MSC ClearRequest BSC<-MSC ClearCommand BSC->MSC ClearComplete BTS<-BSC RF Chan Release BTS->BSC RF Chan Release ACK Sometimes CC message and REL IND message are received swapped (because they are sent by different components asynchronously in TTCN3). As a result, osmo-bsc was failing to go into CLEARING state and was unable to send the ClearRequest because CC was still not received. So the idea is to stay in WAIT_CC until CC is received, then check if the lchan was dropped and in that case go into clearing state. Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b --- M src/osmo-bsc/bsc_subscr_conn_fsm.c 1 file changed, 28 insertions(+), 5 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/08/15408/3 -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 3 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria Gerrit-Reviewer: laforge Gerrit-Reviewer: neels Gerrit-Reviewer: pespin Gerrit-MessageType: newpatchset
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
neels has posted comments on this change. (
https://gerrit.osmocom.org/c/osmo-bsc/+/15408 )
Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated
channel closed during WAIT_CC
..
Patch Set 1: Code-Review-1
(2 comments)
Found one side effect functional change, and got some style nitpicks
https://gerrit.osmocom.org/#/c/15408/1/src/osmo-bsc/bsc_subscr_conn_fsm.c
File src/osmo-bsc/bsc_subscr_conn_fsm.c:
https://gerrit.osmocom.org/#/c/15408/1/src/osmo-bsc/bsc_subscr_conn_fsm.c@343
PS1, Line 343: if (conn->lchan) {
(would prefer the early-exit style; main flow remains undiffed)
if (!conn->lchan) {
log...
state_chg...
clear...
break;
}
conn_fsm_state_chg(ST_ACTIVE);
https://gerrit.osmocom.org/#/c/15408/1/src/osmo-bsc/bsc_subscr_conn_fsm.c@671
PS1, Line 671: if (!conn->lchan && gscon_is_active(conn)) {
Before, when we already were in the ST_CLEARING, we would still re-send the
BSSMAP Clear Request again. I am not sure if that is desired, but if that needs
to change, that should be a separate patch.
It is fine for the BSC to send repeated Clear Requests, they are only polite
hints for the MSC.
Code design wise, it's not such a good idea to have gscon_is_active() listing
all *other* states. If a new state gets added in the future, the author is
almost guaranteed to forget to also change that function.
Instead I would prefer to more explicitly except only this situation, e.g.:
/* If the conn has no lchan anymore, it was released by the BTS and needs
to Clear towards MSC. */
if (!conn->lchan) {
switch (conn->fi_state) {
case ST_INIT:
case ST_WAIT_CC:
/* The SCCP connection was not yet confirmed by a CC, the
BSSAP is not fully established
* yet. First wait for the CC, and release in
gscon_fsm_wait_cc(). */
break;
default:
/* Ensure that the FSM is in ST_CLEARING. */
osmo_fsm_inst_state_chg(...ST_CLEARING...)
/* fall thru, omit an error log if already in ST_CLEARING */
case ST_CLEARING:
/* Request a Clear Command from the MSC.
gscon_bssmap_clear([no diff]
break;
}
}
Are you sure that ST_INIT should also be in that condition?
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b
Gerrit-Change-Number: 15408
Gerrit-PatchSet: 1
Gerrit-Owner: pespin
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria
Gerrit-Reviewer: laforge
Gerrit-Reviewer: neels
Gerrit-Reviewer: pespin
Gerrit-Comment-Date: Mon, 16 Sep 2019 15:51:35 +
Gerrit-HasComments: Yes
Gerrit-Has-Labels: Yes
Gerrit-MessageType: comment
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
laforge has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/15408 ) Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed during WAIT_CC .. Patch Set 1: Code-Review+1 -- To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b Gerrit-Change-Number: 15408 Gerrit-PatchSet: 1 Gerrit-Owner: pespin Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: laforge Gerrit-Comment-Date: Fri, 06 Sep 2019 19:06:05 + Gerrit-HasComments: No Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Change in ...osmo-bsc[master]: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel c...
pespin has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-bsc/+/15408
Change subject: bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated
channel closed during WAIT_CC
..
bsc_subscr_conn_fsm: Cleanly clear BSSAP conn if associated channel closed
during WAIT_CC
TTCN3 BSC_Tests.TC_ms_rel_ind_does_not_cause_bssmap_reset seems to
sometimes run into a race condition on the order of messages received by
osmo-bsc comming from MSC and BTS.
Usual (expected) scenario):
BTS->BSC EST IND
BSC->MSC CL3 Info
BSC<-MSC CC
BTS->BSC REL IND
BTS<-BSC DEACT SACCH
BSC->MSC ClearRequest
BSC<-MSC ClearCommand
BSC->MSC ClearComplete
BTS<-BSC RF Chan Release
BTS->BSC RF Chan Release ACK
Sometimes CC message and REL IND message are received swapped (because they
are sent by different components asynchronously in TTCN3).
As a result, osmo-bsc was failing to go into CLEARING state and was
unable to send the ClearRequest because CC was still not received.
So the idea is to stay in WAIT_CC until CC is received, then check if
the lchan was dropped and in that case go into clearing state.
Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b
---
M src/osmo-bsc/bsc_subscr_conn_fsm.c
1 file changed, 24 insertions(+), 8 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/08/15408/1
diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c
b/src/osmo-bsc/bsc_subscr_conn_fsm.c
index f8784f9..b5edeb8 100644
--- a/src/osmo-bsc/bsc_subscr_conn_fsm.c
+++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c
@@ -99,6 +99,12 @@
conn->network->T_defs, \
-1)
+static bool gscon_is_active(struct gsm_subscriber_connection *conn)
+{
+ enum gscon_fsm_states st = conn->fi->state;
+ return st == ST_ACTIVE || st == ST_ASSIGNMENT || st == ST_HANDOVER;
+}
+
/* forward MT DTAP from BSSAP side to RSL side */
static inline void submit_dtap(struct gsm_subscriber_connection *conn, struct
msgb *msg)
{
@@ -333,10 +339,19 @@
switch (event) {
case GSCON_EV_A_CONN_CFM:
/* MSC has confirmed the connection, we now change into the
-* active state and wait there for further operations */
- conn_fsm_state_chg(ST_ACTIVE);
- /* if there's user payload, forward it just like EV_MT_DTAP */
- /* FIXME: Question: if there's user payload attached to the CC,
forward it like EV_MT_DTAP? */
+* active state and wait there for further operations. */
+ if (conn->lchan) {
+ conn_fsm_state_chg(ST_ACTIVE);
+ /* if there's user payload, forward it just like
EV_MT_DTAP */
+ /* FIXME: Question: if there's user payload attached to
the CC, forward it like EV_MT_DTAP? */
+ } else {
+ /* If associated lchan was released while we were
+* waiting for the confirmed connection, then instead
+* simply drop the connection */
+ LOGPFSML(fi, LOGL_INFO, "Connection confirmed but lchan
was dropped before, clearing conn\n");
+ osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, 999);
+ gscon_bssmap_clear(conn,
GSM0808_CAUSE_EQUIPMENT_FAILURE);
+ }
break;
default:
OSMO_ASSERT(false);
@@ -589,7 +604,7 @@
[ST_WAIT_CC] = {
.name = "WAIT_CC",
.in_event_mask = S(GSCON_EV_A_CONN_CFM),
- .out_state_mask = S(ST_ACTIVE),
+ .out_state_mask = S(ST_ACTIVE) | S(ST_CLEARING),
.action = gscon_fsm_wait_cc,
},
[ST_ACTIVE] = {
@@ -651,9 +666,10 @@
lchan_forget_conn(conn->lchan);
conn->lchan = NULL;
}
- if (!conn->lchan) {
- if (conn->fi->state != ST_CLEARING)
- osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, 999);
+ /* if conn is not active we cannot send bssap. If on WAIT_CC, then let's
+* wait until CC is received to tear down */
+ if (!conn->lchan && gscon_is_active(conn)) {
+ osmo_fsm_inst_state_chg(conn->fi, ST_CLEARING, 60, 999);
gscon_bssmap_clear(conn, GSM0808_CAUSE_EQUIPMENT_FAILURE);
}
}
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/15408
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Id1abf5ee44c60925b478123409f26bd29006202b
Gerrit-Change-Number: 15408
Gerrit-PatchSet: 1
Gerrit-Owner: pespin
Gerrit-MessageType: newchange
