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dexter gerrit-no-reply at lists.osmocom.orgdexter has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/19792 )
Change subject: lchan_fsm: make rsl mode-modify working again
......................................................................
lchan_fsm: make rsl mode-modify working again
osmo-nitb supports the modification of an lchan if the lchan is
compatible but in the wrong mode. This feature was dropped in the
transition to AoIP/bsc-split. However, osmo-bsc still has code to
generate and parse the messeages, but the FSMs do not support a mode
modify yetm
Lets add handling for mode-modify to the lchan_fsm and assignment_fsm in
order to support mode modify again
Change-Id: I2c5a283b1ee33745cc1fcfcc09a0f9382224e2eb
Related: OS#4549
---
M include/osmocom/bsc/lchan_fsm.h
M src/osmo-bsc/abis_rsl.c
M src/osmo-bsc/assignment_fsm.c
M src/osmo-bsc/gsm_04_08_rr.c
M src/osmo-bsc/lchan_fsm.c
5 files changed, 194 insertions(+), 41 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/92/19792/1
diff --git a/include/osmocom/bsc/lchan_fsm.h b/include/osmocom/bsc/lchan_fsm.h
index 55ab024..e5b3707 100644
--- a/include/osmocom/bsc/lchan_fsm.h
+++ b/include/osmocom/bsc/lchan_fsm.h
@@ -18,6 +18,8 @@
LCHAN_ST_WAIT_TS_READY,
LCHAN_ST_WAIT_ACTIV_ACK, /*< After RSL Chan Act Ack, lchan is active but RTP not configured. */
LCHAN_ST_WAIT_RLL_RTP_ESTABLISH,
+ LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK,
+ LCHAN_ST_WAIT_RSL_MT_MODE_MODIFY_ACK,
LCHAN_ST_ESTABLISHED, /*< Active and RTP is fully configured. */
LCHAN_ST_WAIT_RLL_RTP_RELEASED,
LCHAN_ST_WAIT_BEFORE_RF_RELEASE,
@@ -40,10 +42,10 @@
LCHAN_EV_RLL_REL_CONF,
LCHAN_EV_RSL_RF_CHAN_REL_ACK,
LCHAN_EV_RLL_ERR_IND,
-
- /* FIXME: not yet implemented: Chan Mode Modify, see assignment_fsm_start(). */
LCHAN_EV_CHAN_MODE_MODIF_ACK,
LCHAN_EV_CHAN_MODE_MODIF_ERROR,
+ LCHAN_EV_RSL_MT_MODE_MODIFY_ACK,
+ LCHAN_EV_RSL_MT_MODE_MODIFY_NACK,
};
void lchan_fsm_init();
@@ -55,6 +57,8 @@
void lchan_activate(struct gsm_lchan *lchan, struct lchan_activate_info *info);
void lchan_ready_to_switch_rtp(struct gsm_lchan *lchan);
+void lchan_modfy(struct gsm_lchan *lchan, struct lchan_activate_info *info);
+
static inline const char *lchan_state_name(struct gsm_lchan *lchan)
{
return lchan->fi ? osmo_fsm_inst_state_name(lchan->fi) : "NULL";
diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c
index 6787511..42f3a42 100644
--- a/src/osmo-bsc/abis_rsl.c
+++ b/src/osmo-bsc/abis_rsl.c
@@ -1186,10 +1186,12 @@
case RSL_MT_MODE_MODIFY_ACK:
LOG_LCHAN(msg->lchan, LOGL_DEBUG, "CHANNEL MODE MODIFY ACK\n");
count_codecs(sign_link->trx->bts, msg->lchan);
+ osmo_fsm_inst_dispatch(msg->lchan->fi, LCHAN_EV_RSL_MT_MODE_MODIFY_ACK, NULL);
break;
case RSL_MT_MODE_MODIFY_NACK:
LOG_LCHAN(msg->lchan, LOGL_DEBUG, "CHANNEL MODE MODIFY NACK\n");
rate_ctr_inc(&sign_link->trx->bts->bts_ctrs->ctr[BTS_CTR_MODE_MODIFY_NACK]);
+ osmo_fsm_inst_dispatch(msg->lchan->fi, LCHAN_EV_RSL_MT_MODE_MODIFY_NACK, NULL);
break;
case RSL_MT_IPAC_PDCH_ACT_ACK:
rc = rsl_rx_ipacc_pdch(msg, "ACT ACK", TS_EV_PDCH_ACT_ACK);
diff --git a/src/osmo-bsc/assignment_fsm.c b/src/osmo-bsc/assignment_fsm.c
index ca29daa..7592c2a 100644
--- a/src/osmo-bsc/assignment_fsm.c
+++ b/src/osmo-bsc/assignment_fsm.c
@@ -379,9 +379,8 @@
return 0;
}
-/* Check if the conn is already associated with an lchan. If yes, we will check
- * if that lchan is compatible with the preferred rate/codec. If the lchan
- * turns out to be incompatible we try with the alternate rate/codec. */
+/* Decide if we should re-use an existing lchan. For this we check if the
+ * current lchan is compatible with one of the requested modes. */
static bool reuse_existing_lchan(struct gsm_subscriber_connection *conn)
{
struct assignment_request *req = &conn->assignment.req;
@@ -395,22 +394,10 @@
for (i = 0; i < req->n_ch_mode_rate; i++)
if (lchan_type_compat_with_mode(conn->lchan->type, &req->ch_mode_rate[i])) {
conn->lchan->ch_mode_rate = req->ch_mode_rate[i];
- break;
+ return true;
}
- if (i == req->n_ch_mode_rate)
- return false;
-
- if (conn->lchan->tch_mode != conn->lchan->ch_mode_rate.chan_mode) {
- /* FIXME: send Channel Mode Modify to put the current lchan in the right mode, and kick
- * off its RTP stream setup code path. See gsm48_lchan_modify() and
- * gsm48_rx_rr_modif_ack(), and see lchan_fsm.h LCHAN_EV_CHAN_MODE_MODIF_* */
- LOG_ASSIGNMENT(conn, LOGL_DEBUG,
- "Current lchan would be compatible, but Channel Mode Modify is not implemented\n");
- return false;
- }
-
- return true;
+ return false;
}
void assignment_fsm_start(struct gsm_subscriber_connection *conn, struct gsm_bts *bts,
@@ -447,22 +434,60 @@
return;
/* There may be an already existing lchan, if yes, try to work with
- * the existing lchan */
+ * the existing lchan. */
if (reuse_existing_lchan(conn)) {
+
+ /* If the requested mode and the current TCH mode matches up, just send the
+ * assignment complete directly and be done with the assignment procedure.
+ * however, this will be not the common case. */
+ if (conn->lchan->tch_mode == conn->lchan->ch_mode_rate.chan_mode) {
+ LOG_ASSIGNMENT(conn, LOGL_DEBUG,
+ "Current lchan mode is compatible with requested chan_mode,"
+ " sending BSSMAP Assignment Complete directly."
+ " requested chan_mode=%s; current lchan is %s\n",
+ gsm48_chan_mode_name(conn->lchan->ch_mode_rate.chan_mode),
+ gsm_lchan_name(conn->lchan));
+
+ send_assignment_complete(conn);
+ /* If something went wrong during send_assignment_complete(),
+ * the fi will be gone from error handling in there. */
+ if (conn->assignment.fi) {
+ assignment_count_result(CTR_ASSIGNMENT_COMPLETED);
+ osmo_fsm_inst_term(conn->assignment.fi, OSMO_FSM_TERM_REGULAR, 0);
+ }
+ return;
+ }
+
+ /* The requested mode does not match the current TCH mode but the lchan is
+ * compatible. We will initiate a mode modify procedure. */
LOG_ASSIGNMENT(conn, LOGL_DEBUG,
- "Current lchan is compatible with requested chan_mode,"
- " sending BSSMAP Assignment Complete directly."
- " requested chan_mode=%s; current lchan is %s\n",
+ "Current lchan mode is not compatible with requested chan_mode,"
+ " so we will modify it. requested chan_mode=%s; current lchan is %s\n",
gsm48_chan_mode_name(conn->lchan->ch_mode_rate.chan_mode),
gsm_lchan_name(conn->lchan));
- send_assignment_complete(conn);
- /* If something went wrong during send_assignment_complete(), the fi will be gone from
- * error handling in there. */
- if (conn->assignment.fi) {
- assignment_count_result(CTR_ASSIGNMENT_COMPLETED);
- osmo_fsm_inst_term(conn->assignment.fi, OSMO_FSM_TERM_REGULAR, 0);
- }
+ info = (struct lchan_activate_info){
+ .activ_for = FOR_ASSIGNMENT,
+ .for_conn = conn,
+ .chan_mode = conn->lchan->ch_mode_rate.chan_mode,
+ .encr = conn->lchan->encr,
+ .s15_s0 = conn->lchan->ch_mode_rate.s15_s0,
+ .requires_voice_stream = conn->assignment.requires_voice_stream,
+ .msc_assigned_cic = req->msc_assigned_cic,
+ .re_use_mgw_endpoint_from_lchan = conn->lchan,
+ };
+
+ lchan_modfy(conn->lchan, &info);
+
+ /* Since we opted not to allocate a new lchan, the new lchan is
+ * still the old lchan. */
+ conn->assignment.new_lchan = conn->lchan;
+
+ /* Also we need to spare the RR assignment, so we jump forward
+ * and wait for the lchan_fsm until it reaches the established
+ * state again. */
+ assignment_fsm_state_chg(ASSIGNMENT_ST_WAIT_LCHAN_ESTABLISHED);
+
return;
}
@@ -682,6 +707,7 @@
.out_state_mask = 0
| S(ASSIGNMENT_ST_WAIT_LCHAN_ACTIVE)
| S(ASSIGNMENT_ST_WAIT_RR_ASS_COMPLETE)
+ | S(ASSIGNMENT_ST_WAIT_LCHAN_ESTABLISHED) /* MODE MODIFY */
,
},
[ASSIGNMENT_ST_WAIT_RR_ASS_COMPLETE] = {
diff --git a/src/osmo-bsc/gsm_04_08_rr.c b/src/osmo-bsc/gsm_04_08_rr.c
index 69ec4d3..ef0fb4e 100644
--- a/src/osmo-bsc/gsm_04_08_rr.c
+++ b/src/osmo-bsc/gsm_04_08_rr.c
@@ -654,7 +654,6 @@
int gsm48_rx_rr_modif_ack(struct msgb *msg)
{
- int rc;
struct gsm48_hdr *gh = msgb_l3(msg);
struct gsm48_chan_mode_modify *mod =
(struct gsm48_chan_mode_modify *) gh->data;
@@ -688,15 +687,7 @@
break;
}
- /* We've successfully modified the MS side of the channel,
- * now go on to modify the BTS side of the channel */
- rc = rsl_chan_mode_modify_req(msg->lchan);
-
- /* FIXME: we not only need to do this after mode modify, but
- * also after channel activation */
- if (is_ipaccess_bts(msg->lchan->ts->trx->bts) && mod->mode != GSM48_CMODE_SIGN)
- rsl_tx_ipacc_crcx(msg->lchan);
- return rc;
+ return 0;
}
int gsm48_parse_meas_rep(struct gsm_meas_rep *rep, struct msgb *msg)
diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c
index 26bfd29..db72651 100644
--- a/src/osmo-bsc/lchan_fsm.c
+++ b/src/osmo-bsc/lchan_fsm.c
@@ -59,6 +59,7 @@
switch (lchan->fi->state) {
case LCHAN_ST_WAIT_RLL_RTP_ESTABLISH:
case LCHAN_ST_ESTABLISHED:
+ case LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK:
return true;
default:
return false;
@@ -249,7 +250,7 @@
} while(0)
/* Which state to transition to when lchan_fail() is called in a given state. */
-uint32_t lchan_fsm_on_error[32] = {
+uint32_t lchan_fsm_on_error[34] = {
[LCHAN_ST_UNUSED] = LCHAN_ST_UNUSED,
[LCHAN_ST_WAIT_TS_READY] = LCHAN_ST_UNUSED,
[LCHAN_ST_WAIT_ACTIV_ACK] = LCHAN_ST_BORKEN,
@@ -260,6 +261,8 @@
[LCHAN_ST_WAIT_RF_RELEASE_ACK] = LCHAN_ST_BORKEN,
[LCHAN_ST_WAIT_AFTER_ERROR] = LCHAN_ST_UNUSED,
[LCHAN_ST_BORKEN] = LCHAN_ST_BORKEN,
+ [LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK] = LCHAN_ST_BORKEN,
+ [LCHAN_ST_WAIT_RSL_MT_MODE_MODIFY_ACK] = LCHAN_ST_BORKEN,
};
#define lchan_fail(fmt, args...) lchan_fail_to(lchan_fsm_on_error[fi->state], fmt, ## args)
@@ -523,6 +526,53 @@
}
}
+void lchan_modfy(struct gsm_lchan *lchan, struct lchan_activate_info *info)
+{
+ struct osmo_fsm_inst *fi;
+ struct osmo_mgcpc_ep_ci *use_mgwep_ci;
+
+ OSMO_ASSERT(lchan && info);
+ fi = lchan->fi;
+
+ /* It is only possible to modify already established lchans. */
+ if (!lchan_state_is(lchan, LCHAN_ST_ESTABLISHED))
+ goto abort;
+
+ lchan->activate.info = *info;
+ use_mgwep_ci = lchan_use_mgw_endpoint_ci_bts(lchan);
+
+ if (info->chan_mode == GSM48_CMODE_SPEECH_AMR) {
+ if (lchan_mr_config(lchan, info->s15_s0) < 0) {
+ lchan_fail("Can not generate multirate configuration IE\n");
+ return;
+ }
+ }
+
+ LOG_LCHAN(lchan, LOGL_INFO,
+ "Modification requested: %s voice=%s MGW-ci=%s type=%s tch-mode=%s encr-alg=A5/%u ck=%s\n",
+ lchan_activate_mode_name(lchan->activate.info.activ_for),
+ lchan->activate.info.requires_voice_stream ? "yes" : "no",
+ lchan->activate.info.requires_voice_stream ?
+ (use_mgwep_ci ? osmo_mgcpc_ep_ci_name(use_mgwep_ci) : "new")
+ : "none",
+ gsm_lchant_name(lchan->type),
+ gsm48_chan_mode_name(lchan->tch_mode),
+ (lchan->activate.info.encr.alg_id ? : 1) - 1,
+ lchan->activate.info.encr.key_len ? osmo_hexdump_nospc(lchan->activate.info.encr.key,
+ lchan->activate.info.encr.key_len) : "none");
+
+ /* While the mode is changed the lchan is virtually "not activated", at least
+ * from the FSM implementations perspective */
+ lchan->activate.concluded = false;
+
+ /* Initiate mode modfication, start with the MS side (RR) */
+ lchan_fsm_state_chg(LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK);
+ gsm48_lchan_modify(lchan, info->chan_mode);
+ return;
+abort:
+ lchan_release(lchan, !!(lchan->conn), true, RSL_ERR_EQUIPMENT_FAIL);
+}
+
static void lchan_fsm_wait_ts_ready_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct gsm_lchan *lchan = lchan_fi_lchan(fi);
@@ -833,6 +883,59 @@
}
}
+static void lchan_fsm_wait_chan_mode_modif_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+ struct gsm_lchan *lchan = lchan_fi_lchan(fi);
+ int rc;
+
+ switch (event) {
+
+ case LCHAN_EV_CHAN_MODE_MODIF_ACK:
+ lchan_fsm_state_chg(LCHAN_ST_WAIT_RSL_MT_MODE_MODIFY_ACK);
+ rc = rsl_chan_mode_modify_req(lchan);
+ if (rc < 0) {
+ lchan_fail("Failed to send rsl message to change the channel mode on the BTS side: %s in state %s\n",
+ osmo_fsm_event_name(fi->fsm, event),
+ osmo_fsm_inst_state_name(fi));
+ }
+ return;
+
+ case LCHAN_EV_CHAN_MODE_MODIF_ERROR:
+ lchan_fail("Failed to change channel mode on the MS side: %s in state %s\n",
+ osmo_fsm_event_name(fi->fsm, event),
+ osmo_fsm_inst_state_name(fi));
+ return;
+
+ default:
+ OSMO_ASSERT(false);
+ }
+}
+
+static void lchan_fsm_wait_rsl_mt_mode_modify_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+ struct gsm_lchan *lchan = lchan_fi_lchan(fi);
+ switch (event) {
+
+ case LCHAN_EV_RSL_MT_MODE_MODIFY_ACK:
+ /* Prepare an MGW endpoint CI if appropriate. */
+ if (lchan->activate.info.requires_voice_stream) {
+ lchan_fsm_state_chg(LCHAN_ST_WAIT_RLL_RTP_ESTABLISH);
+ lchan_rtp_fsm_start(lchan);
+ } else
+ lchan_fsm_state_chg(LCHAN_ST_ESTABLISHED);
+ return;
+
+ case LCHAN_EV_RSL_MT_MODE_MODIFY_NACK:
+ lchan_fail("Failed to change channel mode on the BTS side: %s in state %s\n",
+ osmo_fsm_event_name(fi->fsm, event),
+ osmo_fsm_inst_state_name(fi));
+ return;
+
+ default:
+ OSMO_ASSERT(false);
+ }
+}
+
static void lchan_fsm_established_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
struct gsm_lchan *lchan = lchan_fi_lchan(fi);
@@ -1223,6 +1326,30 @@
| S(LCHAN_ST_WAIT_RLL_RTP_RELEASED)
,
},
+ [LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK] = {
+ .name = "WAIT_CHAN_MODE_MODIF_ACK",
+ .action = lchan_fsm_wait_chan_mode_modif_ack,
+ .in_event_mask = 0
+ | S(LCHAN_EV_CHAN_MODE_MODIF_ACK)
+ | S(LCHAN_EV_CHAN_MODE_MODIF_ERROR)
+ ,
+ .out_state_mask = 0
+ | S(LCHAN_ST_BORKEN)
+ | S(LCHAN_ST_WAIT_RSL_MT_MODE_MODIFY_ACK)
+ ,
+ },
+ [LCHAN_ST_WAIT_RSL_MT_MODE_MODIFY_ACK] = {
+ .name = "WAIT_RSL_MT_MODE_MODIFY_ACK",
+ .action = lchan_fsm_wait_rsl_mt_mode_modify_ack,
+ .in_event_mask = 0
+ | S(LCHAN_EV_RSL_MT_MODE_MODIFY_ACK)
+ | S(LCHAN_EV_RSL_MT_MODE_MODIFY_NACK)
+ ,
+ .out_state_mask = 0
+ | S(LCHAN_ST_BORKEN)
+ | S(LCHAN_ST_WAIT_RLL_RTP_ESTABLISH)
+ ,
+ },
[LCHAN_ST_ESTABLISHED] = {
.name = "ESTABLISHED",
.onenter = lchan_fsm_established_onenter,
@@ -1239,6 +1366,7 @@
| S(LCHAN_ST_WAIT_RLL_RTP_RELEASED)
| S(LCHAN_ST_WAIT_BEFORE_RF_RELEASE)
| S(LCHAN_ST_WAIT_RF_RELEASE_ACK)
+ | S(LCHAN_ST_WAIT_CHAN_MODE_MODIF_ACK)
,
},
[LCHAN_ST_WAIT_RLL_RTP_RELEASED] = {
@@ -1326,6 +1454,8 @@
OSMO_VALUE_STRING(LCHAN_EV_RLL_ERR_IND),
OSMO_VALUE_STRING(LCHAN_EV_CHAN_MODE_MODIF_ACK),
OSMO_VALUE_STRING(LCHAN_EV_CHAN_MODE_MODIF_ERROR),
+ OSMO_VALUE_STRING(LCHAN_EV_RSL_MT_MODE_MODIFY_ACK),
+ OSMO_VALUE_STRING(LCHAN_EV_RSL_MT_MODE_MODIFY_NACK),
{}
};
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I2c5a283b1ee33745cc1fcfcc09a0f9382224e2eb
Gerrit-Change-Number: 19792
Gerrit-PatchSet: 1
Gerrit-Owner: dexter <pmaier at sysmocom.de>
Gerrit-MessageType: newchange
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