libvlr: Allow 2G auth tuples to be re-used without going through AUTH
If the key_seq we get in the first messages matches the last_tuple, then
both we and the MS already know the key to use and we don't need the
AUTH REQUEST/RESPONSE cycle.
Security wise ... not so good, and so IMHO the 'auth required' option
in the MSC should always be set. But this allows to turn on ciphering on
a channel without doing any MM transaction, and so the MS doesn't turn
on the T3240 timer which allows to have a ciphered silent-call channel
that won't timeout.
Change-Id: Ief840a2ae7a0ffd2bf0bf726f209a79e3f787646
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/libvlr/vlr_auth_fsm.h b/src/libvlr/vlr_auth_fsm.h
index 618462f..1f2cb49 100644
--- a/src/libvlr/vlr_auth_fsm.h
+++ b/src/libvlr/vlr_auth_fsm.h
@@ -35,3 +35,5 @@
uint32_t parent_term_event,
bool is_r99,
bool is_utran);
+
+bool auth_try_reuse_tuple(struct vlr_subscr *vsub, uint8_t key_seq);