add design charts for new context map FSMs

Planning new connection-oriented RUA and SCCP FSMs to
- conquer confusion about hnbgw_context_map release behavior, and
- eradicate SCCP connection leaks.

Related: SYS#6297
Change-Id: I661bf65d79972a732c52732934095e8bfcd99694
This commit is contained in:
Neels Hofmeyr 2023-02-11 05:58:42 +01:00
parent 29f82a7b48
commit e67c4b324c
5 changed files with 192 additions and 0 deletions

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@ -233,6 +233,7 @@ AC_OUTPUT(
doc/Makefile
doc/examples/Makefile
doc/manuals/Makefile
doc/charts/Makefile
contrib/Makefile
contrib/systemd/Makefile
contrib/osmo-hnbgw.spec

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@ -1,4 +1,5 @@
SUBDIRS = \
examples \
manuals \
charts \
$(NULL)

19
doc/charts/Makefile.am Normal file
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@ -0,0 +1,19 @@
msc: \
$(builddir)/hnbgw_context_map.png \
$(NULL)
dot: \
$(builddir)/hnbgw_context_map_fsm.png \
$(NULL)
$(builddir)/%.png: $(srcdir)/%.msc
mscgen -T png -o $@ $<
$(builddir)/%.png: $(srcdir)/%.dot
dot -Tpng $< > $@
.PHONY: poll
# remember current dir: in case the build process removes and recreates the dir, re-enter the new dir
W := "$(PWD)"
poll:
while true; do $(MAKE) -C $W msc dot; sleep 1; done

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@ -0,0 +1,109 @@
msc {
hscale="2";
hnb[label="HNB"],rua[label="OsmoHNBGW\nRUA FSM / HNBAP"],sccp[label="OsmoHNBGW\nSCCP FSM"],cn[label="CN"];
hnb <=> rua [label="RANAP/RUA\n(Iuh)"];
rua <=> sccp [label="FSM events"];
sccp <=> cn [label="RANAP/SCCP/M3UA\n(IuCS, IuPS)"];
...;
...;
--- [label="Create a new context map (always from HNB)"];
hnb => rua [label="RUA Connect\nRANAP InitialUE-Message\nDTAP Location Updating Request"];
rua rbox sccp [label="hnbgw_context_map_alloc()"];
rua abox rua [label="MAP_RUA_ST_INIT"];
sccp abox sccp [label="MAP_SCCP_ST_INIT"];
rua rbox rua [label="MAP_RUA_EV_RX_CONNECT\ndata = ranap_msg"];
rua abox rua [label="MAP_RUA_ST_CONNECTED"];
rua => sccp [label="MAP_SCCP_EV_TX_RANAP_MSG\ndata = ranap_msg"];
sccp abox sccp [label="MAP_SCCP_ST_WAIT_CC"];
sccp => cn [label="SCCP Connection Request\nRANAP InitialUE-Message\nDTAP Location Updating Request"];
...;
sccp <= cn [label="SCCP Connection Confirm"];
sccp abox sccp [label="MAP_SCCP_ST_CONNECTED"];
--- [label="if SCCP CC with payload"];
rua <= sccp [label="MAP_RUA_EV_TX_RANAP_MSG\ndata = ranap_msg"];
hnb <= rua [label="RUA DirectTransfer"];
...;
...;
--- [label="Layer 3 communication"];
sccp <= cn [label="SCCP Data Form 1"];
rua <= sccp [label="MAP_RUA_EV_TX_RANAP_MSG\ndata = ranap_msg"];
hnb <= rua [label="RUA DirectTransfer"];
...;
hnb => rua [label="RUA DirectTransfer"];
rua => sccp [label="MAP_SCCP_EV_TX_RANAP_MSG\ndata = ranap_msg"];
sccp => cn [label="SCCP Data Form 1"];
...;
...;
--- [label="Usual release"];
sccp <= cn [label="SCCP Data Form 1\nIu-ReleaseCommand"];
rua <= sccp [label="MAP_RUA_EV_TX_RANAP_MSG\ndata = ranap_msg"];
hnb <= rua [label="RUA DirectTransfer\nIu-ReleaseCommand"];
...;
hnb => rua [label="RUA Disconnect\nIu-ReleaseComplete"];
rua rbox rua [label="MAP_RUA_EV_RX_DISCONNECT"];
rua abox rua [label="MAP_RUA_ST_DISCONNECTED"];
rua => sccp [label="MAP_SCCP_EV_RAN_DISC\ndata = ranap_msg"];
sccp => cn [label="SCCP Data Form 1\nIu-ReleaseComplete\nNOT 'SCCP Released'! See 3GPP TS 48.006 9.2"];
sccp abox sccp [label="MAP_SCCP_ST_WAIT_RLSD"];
...;
sccp <= cn [label="SCCP Released"];
sccp abox sccp [label="MAP_SCCP_ST_DISCONNECTED"];
rua rbox sccp [label="map_check_released()"];
rua rbox sccp [label="hnbgw_context_map_free()"];
...;
...;
--- [label="Ungraceful release from CN"];
sccp <= cn [label="SCCP Released"];
sccp => cn [label="SCCP Release Complete\n(implicit by libosmo-sigtran)"];
sccp rbox sccp [label="MAP_SCCP_EV_RX_RELEASED"];
sccp note sccp [label="In SCCP there is no \"link loss\".\nIn every case, we will be notified\nvia N-Disconnect prim per SCCP conn."];
sccp abox sccp [label="MAP_SCCP_ST_DISCONNECTED"];
rua <= sccp [label="MAP_RUA_EV_CN_DISC"];
hnb <= rua [label="RUA Disconnect"];
rua abox rua [label="MAP_RUA_ST_DISCONNECTED"];
rua rbox sccp [label="map_check_released()"];
rua rbox sccp [label="hnbgw_context_map_free()"];
...;
...;
...;
--- [label="PCSTATE handling"];
sccp << cn [label="N-PCSTATE.indication\npoint-code unreachable"];
sccp note sccp [label="currently ignored"];
...;
...;
--- [label="Ungraceful release from HNB"];
hnb -x rua [label="link loss"];
rua rbox rua [label="MAP_RUA_EV_HNB_LINK_LOST"];
rua => sccp [label="MAP_SCCP_EV_RAN_DISC"];
sccp => cn [label="SCCP Released"];
sccp abox sccp [label="MAP_SCCP_ST_DISCONNECTED"];
rua abox rua [label="MAP_RUA_ST_DISCONNECTED"];
rua rbox sccp [label="map_check_released()"];
rua rbox sccp [label="hnbgw_context_map_free()"];
...;
...;
--- [label="Ungraceful release from HNB De-Register"];
hnb => rua [label="HNBAP HNB De-Register"];
--- [label="or"];
hnb => rua [label="HNBAP HNB Register\n(HNB restarted)"];
---;
rua rbox rua [label="MAP_RUA_EV_HNB_LINK_LOST"];
hnb <= rua [label="RUA Disconnect"];
hnb note rua [label="TODO: does it make sense to send\nRUA Disconnect per context when HNB is/was gone?\nOr has the HNB implicitly discarded these?"];
rua abox rua [label="MAP_RUA_ST_DISCONNECTED"];
rua => sccp [label="MAP_SCCP_EV_RAN_DISC\nfrom map_rua_disconnected_onenter()"];
sccp abox sccp [label="MAP_SCCP_ST_WAIT_RLSD"];
rua => sccp [label="MAP_SCCP_EV_RAN_DISC\nto skip waiting for SCCP Released from CN"];
sccp => cn [label="SCCP Released"];
sccp abox sccp [label="MAP_SCCP_ST_DISCONNECTED"];
rua rbox sccp [label="map_check_released()"];
rua rbox sccp [label="hnbgw_context_map_free()"];
}

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@ -0,0 +1,62 @@
digraph G {
rankdir=TB
labelloc=t
label="hnb_context_map\nRUA and SCCP FSMs"
HNB_connect [label="HNB",shape=box3d]
rua_to_scu_connect [label="rua_to_scu()",shape=box]
HNB_DT [label="HNB",shape=box3d]
rua_to_scu_DT [label="rua_to_scu()",shape=box]
HNB_DT2 [label="HNB",shape=box3d]
HNB_disconnect [label="HNB",shape=box3d]
rua_to_scu_disconnect [label="rua_to_scu()",shape=box]
CN [shape=box3d]
CN2 [label="CN",shape=box3d]
CN3 [label="CN",shape=box3d]
CN4 [label="CN",shape=box3d]
HNB_connect -> rua_to_scu_connect [label="RUA Connect",style=dotted]
rua_to_scu_connect -> create [label="(1)",style=dotted]
create [label="hnbgw_context_map_alloc()",shape=box]
create -> {RUA_INIT,SCCP_INIT} [label="(1)",style="dashed,bold"]
rua_to_scu_connect -> RUA_CONNECTED [label="(2)\nMAP_RUA_EV_RX_CONNECT",style=dashed]
RUA_CONNECTED -> SCCP_WAIT_CC [label="(2)\nMAP_SCCP_EV_TX_RANAP_MSG",style=dashed]
RUA_INIT -> RUA_CONNECTED -> RUA_DISCONNECTED [style=bold]
SCCP_INIT -> SCCP_WAIT_CC -> SCCP_CONNECTED -> SCCP_WAIT_RLSD -> SCCP_DISCONNECTED [style=bold]
SCCP_CONNECTED -> SCCP_DISCONNECTED [label="SCCP RLSD"]
SCCP_WAIT_CC -> CN [label="(2) SCCP CR",style=dotted]
CN -> SCCP_CONNECTED [label="(3) SCCP CC",style=dashed]
CN4 -> SCCP_CONNECTED [label="(4) SCCP\nData Form 1",style=dotted]
SCCP_CONNECTED -> RUA_CONNECTED [label="(4)\nMAP_RUA_EV_TX_RANAP_MSG",style=dotted]
RUA_CONNECTED -> HNB_DT2 [label="(4)\nRUA DirectTransfer",style=dotted]
HNB_DT -> rua_to_scu_DT [label="(5)\nRUA DirectTransfer",style=dotted]
rua_to_scu_DT -> RUA_CONNECTED [label="(5)\nMAP_RUA_EV_RX_DIRECT_TRANSFER",style=dotted]
RUA_CONNECTED -> SCCP_CONNECTED [label="(5)\nMAP_SCCP_EV_TX_RANAP_MSG",style=dotted]
SCCP_CONNECTED -> CN3 [label="(5) SCCP\nData Form 1",style=dotted]
HNB_disconnect -> rua_to_scu_disconnect [label="(6) RUA Id-Disconnect",style=dotted]
rua_to_scu_disconnect -> RUA_DISCONNECTED [label="(6) MAP_RUA_EV_RX_DISCONNECT",style=dashed]
RUA_DISCONNECTED -> SCCP_WAIT_RLSD [label="(6) MAP_SCCP_EV_RAN_DISC",style=dashed]
CN2 -> SCCP_DISCONNECTED [label="(7) SCCP RLSD",style=dashed]
{RUA_DISCONNECTED,SCCP_DISCONNECTED} -> release [label="onenter",style="dotted,bold"]
release [label="map_check_released()",shape=box]
release -> terminate [label="when both RUA and\nSCCP disconnected",style=dotted]
terminate [label="hnbgw_context_map_free()",shape=octagon]
subgraph cluster_legend {
label=""
style=invisible
A, B, C, D [style=invisible]
A -> B [label="event without\nstate change",style=dotted]
C -> D [label="event changes\nstate to...",style=dashed]
}
}