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neels gerrit-no-reply at lists.osmocom.orgneels has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/24362 )
Change subject: assignment_fsm: allow assignment to a specific lchan
......................................................................
assignment_fsm: allow assignment to a specific lchan
So far the assignment FSM always tried to satisfy the channel mode and
rate by either re-using the current lchan or finding a new, unused
lchan. For VAMOS however, we want to pick one specific lchan.
Add target_lchan to struct assignment_request and skip all mode matching
and lchan selection when a specific target_lchan is set.
Related: SYS#5315 OS#4940
Change-Id: I71e0d4ff4746706e0be5266e4574d70ca432e3d7
---
M include/osmocom/bsc/assignment_fsm.h
M include/osmocom/bsc/gsm_data.h
M src/osmo-bsc/assignment_fsm.c
3 files changed, 94 insertions(+), 19 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/62/24362/1
diff --git a/include/osmocom/bsc/assignment_fsm.h b/include/osmocom/bsc/assignment_fsm.h
index b4af335..d4ed846 100644
--- a/include/osmocom/bsc/assignment_fsm.h
+++ b/include/osmocom/bsc/assignment_fsm.h
@@ -41,6 +41,10 @@
void assignment_fsm_init();
+int reassignment_request_to_lchan(enum assign_for assign_for, struct gsm_lchan *lchan, struct gsm_lchan *to_lchan);
+int reassignment_request_to_chan_type(enum assign_for assign_for, struct gsm_lchan *lchan,
+ enum gsm_chan_t new_lchan_type);
+
void assignment_fsm_start(struct gsm_subscriber_connection *conn, struct gsm_bts *bts,
struct assignment_request *req);
void assignment_reset(struct gsm_subscriber_connection *conn);
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 3ed624f..58ec124 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -154,6 +154,14 @@
/* Rate/codec setting in preference order (need at least 1 !) */
int n_ch_mode_rate;
struct channel_mode_and_rate ch_mode_rate_list[3];
+
+ /* An assignment request usually requests to assign any available lchan, to match above requirements. This may
+ * also choose to just keep the current lchan and merely modify it as appropriate. In these cases, keep
+ * target_lchan == NULL.
+ * In some situations, an assignment to a specific target lchan is requested (congestion resolution, VAMOS
+ * multiplexing, user request via VTY). In these situations, select a target lchan beforehand and point
+ * target_lchan to it. */
+ struct gsm_lchan *target_lchan;
};
/* State of an ongoing Assignment, while the assignment_fsm is still busy. This serves as state separation to keep the
diff --git a/src/osmo-bsc/assignment_fsm.c b/src/osmo-bsc/assignment_fsm.c
index 83d2917..062fcb4 100644
--- a/src/osmo-bsc/assignment_fsm.c
+++ b/src/osmo-bsc/assignment_fsm.c
@@ -438,6 +438,45 @@
return false;
}
+static int _reassignment_request(enum assign_for assign_for, struct gsm_lchan *lchan, struct gsm_lchan *to_lchan,
+ enum gsm_chan_t new_lchan_type)
+{
+ struct gsm_subscriber_connection *conn = lchan->conn;
+ struct assignment_request req = {
+ .assign_for = assign_for,
+ .aoip = gscon_is_aoip(conn),
+ .msc_assigned_cic = conn->user_plane.msc_assigned_cic,
+ .msc_rtp_port = conn->user_plane.msc_assigned_rtp_port,
+ .n_ch_mode_rate = 1,
+ .ch_mode_rate_list = { lchan->current_ch_mode_rate },
+ .target_lchan = to_lchan,
+ };
+
+ if (to_lchan)
+ new_lchan_type = to_lchan->type;
+ req.ch_mode_rate_list[0].chan_rate = chan_t_to_chan_rate(new_lchan_type);
+
+ OSMO_STRLCPY_ARRAY(req.msc_rtp_addr, conn->user_plane.msc_assigned_rtp_addr);
+
+ if (conn->user_plane.mgw_endpoint_ci_msc) {
+ req.use_osmux = osmo_mgcpc_ep_ci_get_crcx_info_to_osmux_cid(conn->user_plane.mgw_endpoint_ci_msc,
+ &req.osmux_cid);
+ }
+
+ return osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_ASSIGNMENT_START, &req);
+}
+
+int reassignment_request_to_lchan(enum assign_for assign_for, struct gsm_lchan *lchan, struct gsm_lchan *to_lchan)
+{
+ return _reassignment_request(assign_for, lchan, to_lchan, 0);
+}
+
+int reassignment_request_to_chan_type(enum assign_for assign_for, struct gsm_lchan *lchan,
+ enum gsm_chan_t new_lchan_type)
+{
+ return _reassignment_request(assign_for, lchan, NULL, new_lchan_type);
+}
+
void assignment_fsm_start(struct gsm_subscriber_connection *conn, struct gsm_bts *bts,
struct assignment_request *req)
{
@@ -470,13 +509,8 @@
if (check_requires_voice_stream(conn) < 0)
return;
- /* There may be an already existing lchan, if yes, try to work with
- * the existing lchan.
- * If an RTP FSM is already set up for the lchan, Mode Modify is not yet supported -- see handling of
- * LCHAN_EV_REQUEST_MODE_MODIFY in lchan_fsm.c. To not break the lchan, do not even attempt to re-use an lchan
- * that already has an RTP stream set up, rather establish a new lchan (that transition is well implemented). */
- if (reuse_existing_lchan(conn) && !conn->lchan->fi_rtp) {
- /* The new lchan is the old lchan, keep new_lchan == NULL. */
+ if (!req->target_lchan && reuse_existing_lchan(conn)) {
+ /* The already existing lchan is suitable for this mode */
conn->assignment.new_lchan = NULL;
/* If the requested mode and the current TCH mode matches up, just send the
@@ -512,19 +546,48 @@
return;
}
- /* Try to allocate a new lchan in order of preference */
- for (i = 0; i < req->n_ch_mode_rate; i++) {
- conn->assignment.new_lchan = lchan_select_by_chan_mode(bts,
- req->ch_mode_rate_list[i].chan_mode, req->ch_mode_rate_list[i].chan_rate);
- if (!conn->assignment.new_lchan)
- continue;
- LOG_ASSIGNMENT(conn, LOGL_DEBUG, "selected new lchan %s for mode[%d] = %s channel_rate=%d\n",
- gsm_lchan_name(conn->assignment.new_lchan),
- i, gsm48_chan_mode_name(req->ch_mode_rate_list[i].chan_mode),
- req->ch_mode_rate_list[i].chan_rate);
+ if (req->target_lchan) {
+ bool matching_mode;
- conn->assignment.selected_ch_mode_rate = req->ch_mode_rate_list[i];
- break;
+ /* The caller already picked a target lchan to assign to. No need to try re-using the current lchan or
+ * picking a new one. */
+ if (!lchan_state_is(req->target_lchan, LCHAN_ST_UNUSED)) {
+ assignment_fail(GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE,
+ "Assignment to lchan %s requested, but lchan is already in use (state=%s)\n",
+ gsm_lchan_name(req->target_lchan),
+ osmo_fsm_inst_state_name(req->target_lchan->fi));
+ return;
+ }
+
+ conn->assignment.new_lchan = req->target_lchan;
+ matching_mode = false;
+ for (i = 0; i < req->n_ch_mode_rate; i++) {
+ if (!lchan_type_compat_with_mode(conn->assignment.new_lchan->type, &req->ch_mode_rate_list[i]))
+ continue;
+ conn->assignment.selected_ch_mode_rate = req->ch_mode_rate_list[i];
+ matching_mode = true;
+ }
+ if (!matching_mode) {
+ assignment_fail(GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE,
+ "Assignment to lchan %s requested, but lchan is not compatible\n",
+ gsm_lchan_name(req->target_lchan));
+ return;
+ }
+ } else {
+ /* Try to allocate a new lchan in order of preference */
+ for (i = 0; i < req->n_ch_mode_rate; i++) {
+ conn->assignment.new_lchan = lchan_select_by_chan_mode(bts,
+ req->ch_mode_rate_list[i].chan_mode, req->ch_mode_rate_list[i].chan_rate);
+ if (!conn->assignment.new_lchan)
+ continue;
+ LOG_ASSIGNMENT(conn, LOGL_DEBUG, "selected new lchan %s for mode[%d] = %s channel_rate=%d\n",
+ gsm_lchan_name(conn->assignment.new_lchan),
+ i, gsm48_chan_mode_name(req->ch_mode_rate_list[i].chan_mode),
+ req->ch_mode_rate_list[i].chan_rate);
+
+ conn->assignment.selected_ch_mode_rate = req->ch_mode_rate_list[i];
+ break;
+ }
}
/* Check whether the lchan allocation was successful or not and tear
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/24362
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I71e0d4ff4746706e0be5266e4574d70ca432e3d7
Gerrit-Change-Number: 24362
Gerrit-PatchSet: 1
Gerrit-Owner: neels <nhofmeyr at sysmocom.de>
Gerrit-MessageType: newchange
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