gprs: Add expiry timeout for subscriber entries

Set the expiry delay after the subscriber has been deleted (e.g. by
freeing the MM context). If cancelled, the subscriber will be deleted
immediately and no timeout will be set. If the expiry time is set to
SGSN_TIMEOUT_NEVER, no timer will be started and the subscriber entry
will be kept until it is cancelled.

The following VTY command is added to the sgsn node:

  - subscriber-expiry-time <0-999999>    set expiry time in seconds
  - no subscriber-expiry-time            set to SGSN_TIMEOUT_NEVER

The default is an expiry time of 0 seconds, which means that the
subscriber entries are wiped out immediately after an MM context is
destroyed.

Note that unused MM contexts are not expired yet. Therefore the
subscriber will only be expired after a successful MM detach.

Sponsored-by: On-Waves ehf

2 files changed, 5 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/gprs_sgsn.h b/openbsc/include/openbsc/gprs_sgsn.h
index c92d1cc7b..e707c77d7 100644
--- a/openbsc/include/openbsc/gprs_sgsn.h
+++ b/openbsc/include/openbsc/gprs_sgsn.h
@@ -276,6 +276,7 @@ struct sgsn_subscriber_data {
 	struct gsm_auth_tuple	auth_triplets[5];
 	int			auth_triplets_updated;
 	int			error_cause;
+	struct osmo_timer_list	timer;
 };
 
 #define LOGGSUBSCRP(level, subscr, fmt, args...) \
diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index 78064dddc..8a4514627 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -7,6 +7,8 @@
 #include <osmocom/gprs/gprs_ns.h>
 #include <openbsc/gprs_sgsn.h>
 
+#define SGSN_TIMEOUT_NEVER (-1)
+
 struct gprs_gsup_client;
 
 enum sgsn_auth_policy {
@@ -31,6 +33,8 @@ struct sgsn_config {
 	struct sockaddr_in gsup_server_addr;
 	int gsup_server_port;
 
+	int subscriber_expiry_timeout;
+
 	int require_authentication;
 	int require_update_location;
 };