ussd: Ignore connection release/clear from the MSC
In case this is a local USSD connection we will ignore
the clear command and respond with a RLC to any RLSD but
will never forward that to the BSC. This way the external
USSD is fully in charge of the connection.
There are theoretical issues if there are multiple transactions
on the same SCCP Connection but this can not be solved properly
right now.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index 4a6e36d..2950745 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -608,6 +608,11 @@
goto send_to_all;
break;
case SCCP_MSG_TYPE_RLSD:
+ if (con && con->con_local == NAT_CON_END_USSD) {
+ LOGP(DNAT, LOGL_NOTICE, "RLSD for a USSD connection. Ignoring.\n");
+ con = NULL;
+ }
+ /* fall through */
case SCCP_MSG_TYPE_CREF:
case SCCP_MSG_TYPE_DT1:
case SCCP_MSG_TYPE_IT:
@@ -623,6 +628,10 @@
LOGP(DNAT, LOGL_ERROR, "Failed to assign...\n");
} else
LOGP(DNAT, LOGL_ERROR, "Assignment command but no BSC.\n");
+ } else if (con && con->con_local == NAT_CON_END_USSD &&
+ parsed->gsm_type == BSS_MAP_MSG_CLEAR_CMD) {
+ LOGP(DNAT, LOGL_NOTICE, "Clear Command for USSD Connection. Ignoring.\n");
+ con = NULL;
}
break;
case SCCP_MSG_TYPE_CC: