libmsc/ussd.c: use connection ref-counting and transactions
A subscriber may have a few active transactions at the same time.
For example, one can receive SMS messages during a call, or during
an active SS/USSD session.
We already have connection ref-counting and transactions for CC
and SMS, so let's also use both for SS/USSD.
Change-Id: I21c6777cb88f1f4f80f75dcd39734e952bd4e8b0
diff --git a/src/libmsc/transaction.c b/src/libmsc/transaction.c
index 28da9f3..f2c80d7 100644
--- a/src/libmsc/transaction.c
+++ b/src/libmsc/transaction.c
@@ -128,6 +128,9 @@
_gsm411_sms_trans_free(trans);
conn_usage_token = MSC_CONN_USE_TRANS_SMS;
break;
+ case GSM48_PDISC_NC_SS:
+ conn_usage_token = MSC_CONN_USE_TRANS_NC_SS;
+ break;
}
if (trans->paging_request) {
diff --git a/src/libmsc/ussd.c b/src/libmsc/ussd.c
index f285fcf..a27d47b 100644
--- a/src/libmsc/ussd.c
+++ b/src/libmsc/ussd.c
@@ -35,6 +35,10 @@
#include <osmocom/msc/osmo_msc.h>
#include <osmocom/msc/vlr.h>
#include <osmocom/msc/gsm_04_08.h>
+#include <osmocom/msc/transaction.h>
+
+/* FIXME: choose a proper range */
+static uint32_t new_callref = 0x20000001;
/* Declarations of USSD strings to be recognised */
const char USSD_TEXT_OWN_NUMBER[] = "*#100#";
@@ -57,19 +61,60 @@
/* Entrypoint - handler function common to all mobile-originated USSDs */
int handle_rcv_ussd(struct gsm_subscriber_connection *conn, struct msgb *msg)
{
- int rc;
+ struct gsm48_hdr *gh = msgb_l3(msg);
+ struct gsm_trans *trans;
struct ss_request req;
- struct gsm48_hdr *gh;
+ uint8_t pdisc, tid;
+ uint8_t msg_type;
+ int rc;
- /* TODO: Use subscriber_connection ref-counting if we ever want
- * to keep the connection alive due ot ongoing USSD exchange.
- * As we answer everytying synchronously so far, there's no need
- * yet */
+ pdisc = gsm48_hdr_pdisc(gh);
+ msg_type = gsm48_hdr_msg_type(gh);
+ tid = gsm48_hdr_trans_id_flip_ti(gh);
- cm_service_request_concludes(conn, msg);
+ /* Associate logging messages with this subscriber */
+ log_set_context(LOG_CTX_VLR_SUBSCR, conn->vsub);
+
+ DEBUGP(DMM, "Received SS/USSD data (trans_id=%x, msg_type=%s)\n",
+ tid, gsm48_pdisc_msgtype_name(pdisc, msg_type));
+
+ /* Reuse existing transaction, or create a new one */
+ trans = trans_find_by_id(conn, pdisc, tid);
+ if (!trans) {
+ /**
+ * According to GSM TS 04.80, section 2.4.2 "Register
+ * (mobile station to network direction)", the REGISTER
+ * message is sent by the mobile station to the network
+ * to assign a new transaction identifier for call independent
+ * supplementary service control and to request or acknowledge
+ * a supplementary service.
+ */
+ if (msg_type != GSM0480_MTYPE_REGISTER) {
+ LOGP(DMM, LOGL_ERROR, "Unexpected message (msg_type=%s), "
+ "transaction is not allocated yet\n",
+ gsm48_pdisc_msgtype_name(pdisc, msg_type));
+ gsm0480_send_ussd_reject(conn, &req,
+ GSM_0480_PROBLEM_CODE_TAG_GENERAL,
+ GSM_0480_GEN_PROB_CODE_UNRECOGNISED);
+ return -EINVAL;
+ }
+
+ DEBUGP(DMM, " -> (new transaction)\n");
+ trans = trans_alloc(conn->network, conn->vsub,
+ pdisc, tid, new_callref++);
+ if (!trans) {
+ DEBUGP(DMM, " -> No memory for trans\n");
+ gsm0480_send_ussd_return_error(conn, &req,
+ GSM0480_ERR_CODE_SYSTEM_FAILURE);
+ return -ENOMEM;
+ }
+
+ trans->conn = msc_subscr_conn_get(conn, MSC_CONN_USE_TRANS_NC_SS);
+ trans->dlci = OMSC_LINKID_CB(msg);
+ cm_service_request_concludes(conn, msg);
+ }
memset(&req, 0, sizeof(req));
- gh = msgb_l3(msg);
rc = gsm0480_decode_ss_request(gh, msgb_l3len(msg), &req);
if (!rc) {
LOGP(DMM, LOGL_ERROR, "SS/USSD message parsing error, "
@@ -101,5 +146,13 @@
GSM0480_ERR_CODE_UNEXPECTED_DATA_VALUE);
}
+ /**
+ * TODO: as we only handle *#100# for now, and always
+ * respond with RELEASE COMPLETE, let's manually free
+ * the transaction here, until the external interface
+ * is implemented.
+ */
+ trans_free(trans);
+
return rc;
}