USSD: save MO USSD's originating MSC's vlr_number

Save the source IPA name in ss_session, so we can send "invalid IMSI"
messages to the originating MSC.

Remove the fixed size from ss->vlr_number (we don't know the size of the
IPA name when it does not come from the database). Add
ss->vlr_number_len to give osmo_gsup_addr_send() the format it expects,
and to have one less place in the code where the IPA names are not
stored as blob.

Looking up the IPA name from struct osmo_gsup_conn could either be done
like in osmo_gsup_server_ccm_cb() by reading the IPA IEs (which has a
FIXME comment), or by finding the route associated with conn. I went
with the latter approach, because it seems cleaner to me.

Related: OS#3710
Change-Id: If5a65f471672949192061c5fe396603611123bc1

1 files changed, 17 insertions, 7 deletions

diff --git a/src/gsup_router.c b/src/gsup_router.c
index 4fedd38..df978ba 100644
--- a/src/gsup_router.c
+++ b/src/gsup_router.c
@@ -25,13 +25,7 @@
 
 #include "logging.h"
 #include "gsup_server.h"
-
-struct gsup_route {
-	struct llist_head list;
-
-	uint8_t *addr;
-	struct osmo_gsup_conn *conn;
-};
+#include "gsup_router.h"
 
 /*! Find a route for the given address.
  * \param[in] gs gsup server
@@ -53,6 +47,22 @@ struct osmo_gsup_conn *gsup_route_find(struct osmo_gsup_server *gs,
 	return NULL;
 }
 
+/*! Find a GSUP connection's route (to read the IPA address from the route).
+ * \param[in] conn GSUP connection
+ * \return GSUP route
+ */
+struct gsup_route *gsup_route_find_by_conn(const struct osmo_gsup_conn *conn)
+{
+	struct gsup_route *gr;
+
+	llist_for_each_entry(gr, &conn->server->routes, list) {
+		if (gr->conn == conn)
+			return gr;
+	}
+
+	return NULL;
+}
+
 /* add a new route for the given address to the given conn */
 int gsup_route_add(struct osmo_gsup_conn *conn, const uint8_t *addr, size_t addrlen)
 {