gsm_04_08: Add a operation to enable ciphering on a lchan

This will take care of the auth/check/enable cipher sequence
and call a callback function when done.

Currently the negotiated Kc is saved but not re-used, so
there is an authentication each time ...

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/openbsc/src/talloc_ctx.c b/openbsc/src/talloc_ctx.c
index 4b373b4..8e7ec23 100644
--- a/openbsc/src/talloc_ctx.c
+++ b/openbsc/src/talloc_ctx.c
@@ -4,6 +4,7 @@
 extern void *tall_msgb_ctx;
 extern void *tall_fle_ctx;
 extern void *tall_locop_ctx;
+extern void *tall_authciphop_ctx;
 extern void *tall_gsms_ctx;
 extern void *tall_subscr_ctx;
 extern void *tall_sub_req_ctx;
@@ -22,6 +23,7 @@
 	tall_fle_ctx = talloc_named_const(tall_bsc_ctx, 0,
 					  "bs11_file_list_entry");
 	tall_locop_ctx = talloc_named_const(tall_bsc_ctx, 0, "loc_updating_oper");
+	tall_authciphop_ctx = talloc_named_const(tall_bsc_ctx, 0, "auth_ciph_oper");
 	tall_gsms_ctx = talloc_named_const(tall_bsc_ctx, 0, "sms");
 	tall_subscr_ctx = talloc_named_const(tall_bsc_ctx, 0, "subscriber");
 	tall_sub_req_ctx = talloc_named_const(tall_bsc_ctx, 0, "subscr_request");