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, 9 insertions, 0 deletions

diff --git a/src/gsup_router.h b/src/gsup_router.h
index 282531d..bff484e 100644
--- a/src/gsup_router.h
+++ b/src/gsup_router.h
@@ -3,9 +3,18 @@
 #include <stdint.h>
 #include "gsup_server.h"
 
+struct gsup_route {
+	struct llist_head list;
+
+	uint8_t *addr;
+	struct osmo_gsup_conn *conn;
+};
+
 struct osmo_gsup_conn *gsup_route_find(struct osmo_gsup_server *gs,
 					const uint8_t *addr, size_t addrlen);
 
+struct gsup_route *gsup_route_find_by_conn(const struct osmo_gsup_conn *conn);
+
 /* 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);