Withdraw nameservers when the interface goes down.

Problem reported by deraadt some time ago.

diff --git a/sbin/slaacd/engine.c b/sbin/slaacd/engine.c
index ad050cc..ed5ee83 100644 (file)
--- a/sbin/slaacd/engine.c
+++ b/sbin/slaacd/engine.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: engine.c,v 1.66 2021/03/07 10:31:20 florian Exp $     */
+/*     $OpenBSD: engine.c,v 1.67 2021/03/07 10:31:57 florian Exp $     */
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -273,6 +273,7 @@ void                         engine_showinfo_ctl(struct imsg *, uint32_t);
 void                    debug_log_ra(struct imsg_ra *);
 int                     in6_mask2prefixlen(struct in6_addr *);
 void                    deprecate_all_proposals(struct slaacd_iface *);
+void                    send_rdns_withdraw(struct slaacd_iface *);
 #endif /* SMALL */
 struct slaacd_iface    *get_slaacd_iface_by_id(uint32_t);
 void                    remove_slaacd_iface(uint32_t);
@@ -956,6 +957,7 @@ engine_showinfo_ctl(struct imsg *imsg, uint32_t if_index)
                break;
        }
 }
+
 void
 deprecate_all_proposals(struct slaacd_iface *iface)
 {
@@ -969,6 +971,19 @@ deprecate_all_proposals(struct slaacd_iface *iface)
                addr_proposal->state = PROPOSAL_NEARLY_EXPIRED;
        }
 }
+
+void
+send_rdns_withdraw(struct slaacd_iface *iface)
+{
+       struct rdns_proposal    *rdns_proposal;
+
+       while(!LIST_EMPTY(&iface->rdns_proposals)) {
+               rdns_proposal = LIST_FIRST(&iface->rdns_proposals);
+               free_rdns_proposal(rdns_proposal);
+       }
+       compose_rdns_proposal(iface->if_index, iface->rdomain);
+}
+
 #endif /* SMALL */
 
 struct slaacd_iface*
@@ -1135,6 +1150,7 @@ engine_update_iface(struct imsg_ifinfo *imsg_ifinfo)
        else {
                /* XXX correct state transition */
 #ifndef        SMALL
+               send_rdns_withdraw(iface);
                deprecate_all_proposals(iface);
 #endif /* SMALL */
                iface->state = IF_DOWN;