NS: Add support for GPRS NS IP Sub-Network-Service (SNS)

The NS implementation part of the Gb implementation libosmogb
so far implemented a rather classic dialect of Gb, with lots of
heritage to FR (Frame Relay) transports.  At least since Release 6
of the NS specification, there's an IP Sub-Network Service (SNS),
which
* permits for dynamic configuration of IP endpoints and their NS-VCs
* abandons the concept of a NSVCI on IP transport
* forbids the use of RESET/BLOCK/UNBLOCK procedures on IP transport

This commit introduces BSS-side IP-SNS support to libosmogb in a
minimally invasive way.  It adds a corresponding SNS FSM to each NS
instance, and implements the new SIZE/CONFIG/ADD/DELETE/CHANGE_WEIGHT
procedures very closely aligned with the spec.

In order to use the SNS flavor (rather than the classic one),
a BSS implementation should use gprs_ns_nsip_connect_sns() instead
of the existing gprs_ns_nsip_connect().

This implementation comes with a set of TTCN-3 tests in
PCU_Tests_RAW_SNS.ttcn, see Change-ID
I0fe3d4579960bab0494c294ec7ab8032feed4fb2 of osmo-ttcn3-hacks.git

Closes: OS#3372
Closes: OS#3617
Change-Id: I84786c3b43a8ae34ef3b3ba84b33c90042d234ea

1 files changed, 13 insertions, 0 deletions

diff --git a/src/gb/gb_internal.h b/src/gb/gb_internal.h
index 72d940f5..cc7222e8 100644
--- a/src/gb/gb_internal.h
+++ b/src/gb/gb_internal.h
@@ -4,7 +4,17 @@
 #include <osmocom/gsm/tlv.h>
 #include <osmocom/gprs/gprs_ns.h>
 
+/* gprs_ns_sns.c */
+int gprs_ns_rx_sns(struct gprs_ns_inst *nsi, struct msgb *msg, struct tlv_parsed *tp);
+
+struct osmo_fsm_inst *gprs_sns_bss_fsm_alloc(void *ctx, struct gprs_nsvc *nsvc, const char *id);
+int gprs_sns_bss_fsm_start(struct gprs_ns_inst *nsi);
+
+int gprs_sns_init(void);
+
+/* gprs_ns.c */
 void gprs_nsvc_start_test(struct gprs_nsvc *nsvc);
+void gprs_start_alive_all_nsvcs(struct gprs_ns_inst *nsi);
 int gprs_ns_tx_sns_ack(struct gprs_nsvc *nsvc, uint8_t trans_id, uint8_t *cause,
 		       const struct gprs_ns_ie_ip4_elem *ip4_elems,unsigned int num_ip4_elems);
 
@@ -18,3 +28,6 @@ int gprs_ns_tx_sns_size(struct gprs_nsvc *nsvc, bool reset_flag, uint16_t max_nr
 			uint16_t *ip4_ep_nr, uint16_t *ip6_ep_nr);
 
 int gprs_ns_tx_sns_size_ack(struct gprs_nsvc *nsvc, uint8_t *cause);
+
+struct vty;
+void gprs_sns_dump_vty(struct vty *vty, const struct gprs_ns_inst *nsi, bool stats);