I thought the RAN should send a RLSD to the MSC, but 3GPP TS 48.006 (9.2
Connection release) is clear:
"The MSC sends a SCCP released message. This message shall not contain any user
data field."
So we do all of the Iu-ReleaseCommand and Iu-ReleaseComplete in N_DATA prims,
and only after that will the MSC send an SCCP RLSD.
So the new SCCP FSM in osmo-hnbgw doesn't stick around to wait for a RLC, it
sticks around to wait for a RLSD. libosmo-sigtran sends that up the sap as
N_DISCONNECT and takes care of the RLC implicitly.
~N
On Thu, Feb 16, 2023 at 05:28:04AM +0100, Neels Hofmeyr wrote:
> I'm trying to clean up the connection management in osmo-hnbgw.
> For that purpose I'd like to be notified of the SCCP RLC message:
> I'd like to free a HNB-to-CN / RUA-to-SCCP context mapping when the SCCP local
> reference becomes invalid.
> I kind of thought I would receive a OSMO_SCU_PRIM_N_DISCONNECT PRIM_OP_CONFIRM
> up the user_sap, but that's not happening.
>
> I see the SCCP RLC logged like this:
>
> 20230216042453894 DLSS7 DEBUG 0: asp-asp-clnt-OsmoHNBGW: xua_cli_read_cb():
> sctp_recvmsg() returned 40 (flags=0x80) (osmo_ss7.c:1906)
> 20230216042453894 DLM3UA DEBUG 0: asp-asp-clnt-OsmoHNBGW: Received M3UA
> Message (XFER:DATA) (m3ua.c:714)
> 20230216042453894 DLM3UA DEBUG 0: asp-asp-clnt-OsmoHNBGW: m3ua_rx_xfer
> (m3ua.c:543)
> 20230216042453894 DLM3UA DEBUG 0: asp-asp-clnt-OsmoHNBGW: m3ua_rx_xfer():
> M3UA data header: opc=188=0.23.4 dpc=189=0.23.5 (m3ua.c:566)
> 20230216042453894 DLSS7 DEBUG m3ua_hmdc_rx_from_l2(): found dpc=189=0.23.5 as
> local (osmo_ss7_hmrt.c:276)
> 20230216042453894 DLSS7 DEBUG scrc_rx_mtp_xfer_ind_xua:
> HDR=(CO:RELCO,V=0,LEN=0), PART(T=Destination Reference,L=4,D=000003f0),
> PART(T=Source Reference,L=4,D=0073dcf0) (sccp_scrc.c:472)
> 20230216042453894 DLSCCP DEBUG Received CO:RELCO for local reference 1008
> (sccp_scoc.c:1799)
> 20230216042453894 DLSCCP DEBUG SCCP-SCOC(1008)[0x612000008da0]{DISCONN_PEND}:
> Received Event RCOC-RELEASE_COMPLETE.ind (sccp_scoc.c:1833)
> 20230216042453894 DLSCCP DEBUG SCCP-SCOC(1008)[0x612000008da0]{DISCONN_PEND}:
> state_chg to IDLE (sccp_scoc.c:1309)
> 20230216042453894 DLSCCP DEBUG SCCP-SCOC(1008)[0x612000008da0]{IDLE}:
> Terminating (cause = OSMO_FSM_TERM_REQUEST) (sccp_scoc.c:539)
> 20230216042453894 DLSCCP DEBUG SCCP-SCOC(1008)[0x612000008da0]{IDLE}: Freeing
> instance (sccp_scoc.c:539)
> 20230216042453894 DLSCCP DEBUG SCCP-SCOC(1008)[0x612000008da0]{IDLE}:
> Deallocated (fsm.c:568)
>
> but nothing arrives at sccp_sap_up() in hnbgw_cn.c
> Is my idea flawed somehow, or is the prim dispatch missing in libosmo-sigtran?
>
> Thanks!
> ~N
--
- Neels Hofmeyr <[email protected]> http://www.sysmocom.de/
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