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authorNeels Hofmeyr <neels@hofmeyr.de>2020-07-09 15:54:40 +0200
committerlaforge <laforge@osmocom.org>2020-07-16 12:03:19 +0000
commitb523f54de4f9b733ce74ffe245e27418d4c8ed35 (patch)
tree1c6070a981bee988968b90a3fe756fc693bf83b3
parent954ee0a4b8a3505ac5014c4099b9b3655c872efa (diff)
RR Channel Release: pass Cause code from BSSMAP Clear to the BTS
In lchan.release, add 'cause_rr', and set RR Channel Release message's cause value to lchan.release.cause_rr. In lchan_release(), do not set lchan.release.rsl_error_cause to the RR cause value, these are unrelated. Store in new lchan.release.cause_rr instead. The rsl_error_cause is apparently only used for logging, except for one place in lchan_fsm_wait_activ_ack() that compares it to RSL_ERR_RCH_ALR_ACTV_ALLOC, so there should not be a functional difference by this fix. Propagate the BSSMAP Clear Command cause to the RR Channel Release: Add struct gscon_clear_cmd_data as event data for GSCON_EV_A_CLEAR_CMD -- so far it sent the is_csfb flag, add the gsm0808_cause; invoking the event happens in bssmap_handle_clear_cmd(). Adjust event handling in gscon_fsm_allstate(); there, pass the cause to gscon_release_lchans(). In gscon_release_lchans(), pass the cause to gscon_release_lchan(), and then lchan_release(), which sets the new lchan.release.cause_rr to the passed cause value. As soon as the lchan FSM enters the proper state, it calls gsm48_send_rr_release(). There, set the cause value in the encoded message to lchan.release.cause_rr. Interworking with osmo-msc: so far, osmo-msc fails to set the Clear Command cause code for normal release, it just passes 0 which amounts to GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE. Before this patch, osmo-bsc always sent GSM48_RR_CAUSE_NORMAL in the RR Channel Release, and after this patch it will receive 0 == GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE from osmo-msc and more accurately translate that to GSM48_RR_CAUSE_PROT_ERROR_UNSPC. This means in practice that we will now see an error cause in RR Channel Release instead of GSM48_RR_CAUSE_NORMAL when working with osmo-msc. For changing osmo-msc to send GSM0808_CAUSE_CALL_CONTROL instead (which translates to GSM48_RR_CAUSE_NORMAL), see OS#4664 and change-id I1347ed72ae7d7ea73a557b866e764819c5ef8c42 (osmo-msc). A test for this is in Ie6c99f28b610a67f2d59ec00b3541940e882251b (osmo-ttcn3-hacks). Related: SYS#4872 Change-Id: I734cc55c501d61bbdadee81a223b26f9df57f959
-rw-r--r--include/osmocom/bsc/bsc_subscr_conn_fsm.h9
-rw-r--r--include/osmocom/bsc/gsm_data.h3
-rw-r--r--src/osmo-bsc/bsc_subscr_conn_fsm.c15
-rw-r--r--src/osmo-bsc/gsm_04_08_rr.c2
-rw-r--r--src/osmo-bsc/gsm_data.c27
-rw-r--r--src/osmo-bsc/lchan_fsm.c4
-rw-r--r--src/osmo-bsc/osmo_bsc_bssap.c16
7 files changed, 64 insertions, 12 deletions
diff --git a/include/osmocom/bsc/bsc_subscr_conn_fsm.h b/include/osmocom/bsc/bsc_subscr_conn_fsm.h
index 5475272b0..1a827d95c 100644
--- a/include/osmocom/bsc/bsc_subscr_conn_fsm.h
+++ b/include/osmocom/bsc/bsc_subscr_conn_fsm.h
@@ -1,4 +1,6 @@
#pragma once
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/core/fsm.h>
enum gscon_fsm_event {
@@ -40,6 +42,11 @@ enum gscon_fsm_event {
GSCON_EV_FORGET_MGW_ENDPOINT,
};
+struct gscon_clear_cmd_data {
+ enum gsm0808_cause cause_0808;
+ bool is_csfb;
+};
+
struct gsm_subscriber_connection;
struct gsm_network;
struct msgb;
@@ -71,7 +78,7 @@ void gscon_start_assignment(struct gsm_subscriber_connection *conn,
struct assignment_request *req);
void gscon_change_primary_lchan(struct gsm_subscriber_connection *conn, struct gsm_lchan *new_lchan);
-void gscon_release_lchans(struct gsm_subscriber_connection *conn, bool do_rr_release);
+void gscon_release_lchans(struct gsm_subscriber_connection *conn, bool do_rr_release, enum gsm48_rr_cause cause_rr);
void gscon_lchan_releasing(struct gsm_subscriber_connection *conn, struct gsm_lchan *lchan);
void gscon_forget_lchan(struct gsm_subscriber_connection *conn, struct gsm_lchan *lchan);
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 5336ebef2..43d7040fc 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -571,6 +571,7 @@ struct gsm_lchan {
* flag, so that the lchan will gracefully release at the next sensible junction. */
bool requested;
bool do_rr_release;
+ enum gsm48_rr_cause rr_cause;
/* There is an RSL error cause of value 0, so we need a separate flag. */
bool in_error;
@@ -1896,4 +1897,6 @@ int bts_count_free_ts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan);
bool trx_has_valid_pchan_config(const struct gsm_bts_trx *trx);
+enum gsm48_rr_cause bsc_gsm48_rr_cause_from_gsm0808_cause(enum gsm0808_cause c);
+
#endif /* _GSM_DATA_H */
diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c b/src/osmo-bsc/bsc_subscr_conn_fsm.c
index 1d3024610..0ed6715be 100644
--- a/src/osmo-bsc/bsc_subscr_conn_fsm.c
+++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c
@@ -182,14 +182,14 @@ static void gscon_release_lchan(struct gsm_subscriber_connection *conn, struct g
lchan_release(lchan, do_rr_release, err, cause_rr);
}
-void gscon_release_lchans(struct gsm_subscriber_connection *conn, bool do_rr_release)
+void gscon_release_lchans(struct gsm_subscriber_connection *conn, bool do_rr_release, enum gsm48_rr_cause cause_rr)
{
if (conn->ho.fi)
handover_end(conn, HO_RESULT_CONN_RELEASE);
assignment_reset(conn);
- gscon_release_lchan(conn, conn->lchan, do_rr_release, false, 0);
+ gscon_release_lchan(conn, conn->lchan, do_rr_release, false, cause_rr);
}
static void handle_bssap_n_connect(struct osmo_fsm_inst *fi, struct osmo_scu_prim *scu_prim)
@@ -746,17 +746,20 @@ void gscon_forget_mgw_endpoint_ci(struct gsm_subscriber_connection *conn, struct
static void gscon_fsm_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct gsm_subscriber_connection *conn = fi->priv;
+ const struct gscon_clear_cmd_data *ccd;
/* Regular allstate event processing */
switch (event) {
case GSCON_EV_A_CLEAR_CMD:
+ OSMO_ASSERT(data);
+ ccd = data;
if (conn->lchan)
- conn->lchan->release.is_csfb = *(bool *)data;
+ conn->lchan->release.is_csfb = ccd->is_csfb;
/* MSC tells us to cleanly shut down */
if (conn->fi->state != ST_CLEARING)
osmo_fsm_inst_state_chg(fi, ST_CLEARING, 60, 999);
LOGPFSML(fi, LOGL_DEBUG, "Releasing all lchans (if any) after BSSMAP Clear Command\n");
- gscon_release_lchans(conn, true);
+ gscon_release_lchans(conn, true, bsc_gsm48_rr_cause_from_gsm0808_cause(ccd->cause_0808));
/* FIXME: Release all terestrial resources in ST_CLEARING */
/* According to 3GPP 48.008 3.1.9.1. "The BSS need not wait for the radio channel
* release to be completed or for the guard timer to expire before returning the
@@ -833,7 +836,9 @@ static void gscon_pre_term(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause ca
}
LOGPFSML(fi, LOGL_DEBUG, "Releasing all lchans (if any) because this conn is terminating\n");
- gscon_release_lchans(conn, true);
+ /* when things go smoothly, the lchan should have been released before FSM instance termination. So if this is
+ * necessary it's probably "abnormal". */
+ gscon_release_lchans(conn, true, GSM48_RR_CAUSE_ABNORMAL_UNSPEC);
/* drop pending messages */
gscon_dtap_queue_flush(conn, 0);
diff --git a/src/osmo-bsc/gsm_04_08_rr.c b/src/osmo-bsc/gsm_04_08_rr.c
index f425b1636..07978de30 100644
--- a/src/osmo-bsc/gsm_04_08_rr.c
+++ b/src/osmo-bsc/gsm_04_08_rr.c
@@ -303,7 +303,7 @@ int gsm48_send_rr_release(struct gsm_lchan *lchan)
gh->msg_type = GSM48_MT_RR_CHAN_REL;
cause = msgb_put(msg, 1);
- cause[0] = GSM48_RR_CAUSE_NORMAL;
+ cause[0] = lchan->release.rr_cause;
if (lchan->release.is_csfb) {
uint8_t buf[CELL_SEL_IND_AFTER_REL_MAX_BYTES];
diff --git a/src/osmo-bsc/gsm_data.c b/src/osmo-bsc/gsm_data.c
index f790b90d8..860e236fe 100644
--- a/src/osmo-bsc/gsm_data.c
+++ b/src/osmo-bsc/gsm_data.c
@@ -1840,3 +1840,30 @@ bool trx_has_valid_pchan_config(const struct gsm_bts_trx *trx)
return result;
}
+
+/* This may be specific to RR Channel Release, and the mappings were chosen by pure naive guessing without a proper
+ * specification available. */
+enum gsm48_rr_cause bsc_gsm48_rr_cause_from_gsm0808_cause(enum gsm0808_cause c)
+{
+ switch (c) {
+ case GSM0808_CAUSE_PREEMPTION:
+ return GSM48_RR_CAUSE_PREMPTIVE_REL;
+ case GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE:
+ case GSM0808_CAUSE_INVALID_MESSAGE_CONTENTS:
+ case GSM0808_CAUSE_INFORMATION_ELEMENT_OR_FIELD_MISSING:
+ case GSM0808_CAUSE_INCORRECT_VALUE:
+ case GSM0808_CAUSE_UNKNOWN_MESSAGE_TYPE:
+ case GSM0808_CAUSE_UNKNOWN_INFORMATION_ELEMENT:
+ return GSM48_RR_CAUSE_PROT_ERROR_UNSPC;
+ case GSM0808_CAUSE_CALL_CONTROL:
+ case GSM0808_CAUSE_HANDOVER_SUCCESSFUL:
+ case GSM0808_CAUSE_BETTER_CELL:
+ case GSM0808_CAUSE_DIRECTED_RETRY:
+ case GSM0808_CAUSE_REDUCE_LOAD_IN_SERVING_CELL:
+ case GSM0808_CAUSE_RELOCATION_TRIGGERED:
+ case GSM0808_CAUSE_ALT_CHAN_CONFIG_REQUESTED:
+ return GSM48_RR_CAUSE_NORMAL;
+ default:
+ return GSM48_RR_CAUSE_ABNORMAL_UNSPEC;
+ }
+}
diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c
index 68eef4b8b..dfb8a053d 100644
--- a/src/osmo-bsc/lchan_fsm.c
+++ b/src/osmo-bsc/lchan_fsm.c
@@ -402,6 +402,8 @@ static void lchan_reset(struct gsm_lchan *lchan)
.meas_rep_last_seen_nr = 255,
.last_error = lchan->last_error,
+
+ .release.rr_cause = GSM48_RR_CAUSE_NORMAL,
};
}
@@ -1369,8 +1371,8 @@ void lchan_release(struct gsm_lchan *lchan, bool do_rr_release,
struct osmo_fsm_inst *fi = lchan->fi;
lchan->release.in_error = err;
- lchan->release.rsl_error_cause = cause_rr;
lchan->release.do_rr_release = do_rr_release;
+ lchan->release.rr_cause = cause_rr;
/* States waiting for events will notice the desire to release when done waiting, so it is enough
* to mark for release. */
diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c
index 2deb7f46b..1cacfe935 100644
--- a/src/osmo-bsc/osmo_bsc_bssap.c
+++ b/src/osmo-bsc/osmo_bsc_bssap.c
@@ -453,15 +453,23 @@ static int bssmap_handle_clear_cmd(struct gsm_subscriber_connection *conn,
struct msgb *msg, unsigned int length)
{
struct tlv_parsed tp;
- bool is_csfb = false;
+ struct gscon_clear_cmd_data ccd = {
+ .is_csfb = false,
+ };
tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, length - 1, 0, 0);
- /* FIXME: Check for mandatory cause IE, and use that in RR RELEASE cause! */
+ ccd.cause_0808 = gsm0808_get_cause(&tp);
+ if (ccd.cause_0808 < 0) {
+ LOGPFSML(conn->fi, LOGL_ERROR, "Clear Command: Mandatory Cause IE not present.\n");
+ /* Clear anyway, but without a proper cause. */
+ ccd.cause_0808 = GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE;
+ }
+
if (TLVP_PRESENT(&tp, GSM0808_IE_CSFB_INDICATION))
- is_csfb = true;
+ ccd.is_csfb = true;
- osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_A_CLEAR_CMD, &is_csfb);
+ osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_A_CLEAR_CMD, &ccd);
return 0;
}