Handle RTM_DELETE of slaacd managed default route by re-inserting it.

Problem pointed out & OK phessler

4 files changed, 95 insertions, 9 deletions

diff --git a/sbin/slaacd/engine.c b/sbin/slaacd/engine.c
index 184b349f650..86dc07f06d0 100644
--- a/sbin/slaacd/engine.c
+++ b/sbin/slaacd/engine.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: engine.c,v 1.24 2018/04/23 13:49:04 florian Exp $	*/
+/*	$OpenBSD: engine.c,v 1.25 2018/05/17 13:39:00 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -259,6 +259,8 @@ struct address_proposal	*find_address_proposal_by_addr(struct slaacd_iface *,
 			     struct sockaddr_in6 *);
 struct dfr_proposal	*find_dfr_proposal_by_id(struct slaacd_iface *,
 			     int64_t);
+struct dfr_proposal	*find_dfr_proposal_by_gw(struct slaacd_iface *,
+			     struct sockaddr_in6 *);
 void			 find_prefix(struct slaacd_iface *, struct
 			     address_proposal *, struct radv **, struct
 			     radv_prefix **);
@@ -389,6 +391,7 @@ engine_dispatch_frontend(int fd, short event, void *bula)
 	struct address_proposal		*addr_proposal = NULL;
 	struct dfr_proposal		*dfr_proposal = NULL;
 	struct imsg_del_addr		 del_addr;
+	struct imsg_del_route		 del_route;
 	ssize_t				 n;
 	int				 shut = 0;
 #ifndef	SMALL
@@ -521,6 +524,28 @@ engine_dispatch_frontend(int fd, short event, void *bula)
 			}
 
 			break;
+		case IMSG_DEL_ROUTE:
+			if (imsg.hdr.len != IMSG_HEADER_SIZE +
+			    sizeof(del_route))
+				fatal("%s: IMSG_DEL_ROUTE wrong length: %d",
+				    __func__, imsg.hdr.len);
+			memcpy(&del_route, imsg.data, sizeof(del_route));
+			iface = get_slaacd_iface_by_id(del_addr.if_index);
+			if (iface == NULL) {
+				log_debug("IMSG_DEL_ROUTE: unknown interface"
+				    ", ignoring");
+				break;
+			}
+
+			dfr_proposal = find_dfr_proposal_by_gw(iface,
+			    &del_route.gw);
+
+			if (dfr_proposal) {
+				dfr_proposal->state = PROPOSAL_WITHDRAWN;
+				free_dfr_proposal(dfr_proposal);
+				start_probe(iface);
+			}
+			break;
 		default:
 			log_debug("%s: unexpected imsg %d", __func__,
 			    imsg.hdr.type);
@@ -1932,10 +1957,7 @@ configure_dfr(struct dfr_proposal *dfr_proposal)
 
 	if (prev_state == PROPOSAL_CONFIGURED || prev_state ==
 	    PROPOSAL_NEARLY_EXPIRED) {
-		/*
-		 * nothing to do here, routes do not expire in the kernel
-		 * XXX check if the route got deleted and re-add it?
-		 */
+		/* nothing to do here, routes do not expire in the kernel */
 		return;
 	}
 
@@ -2276,6 +2298,20 @@ find_dfr_proposal_by_id(struct slaacd_iface *iface, int64_t id)
 	return (NULL);
 }
 
+struct dfr_proposal*
+find_dfr_proposal_by_gw(struct slaacd_iface *iface, struct sockaddr_in6
+    *addr)
+{
+	struct dfr_proposal	*dfr_proposal;
+
+	LIST_FOREACH (dfr_proposal, &iface->dfr_proposals, entries) {
+		if (memcmp(&dfr_proposal->addr, addr, sizeof(*addr)) == 0)
+			return (dfr_proposal);
+	}
+
+	return (NULL);
+}
+
 
 /* XXX currently unused */
 void
diff --git a/sbin/slaacd/frontend.c b/sbin/slaacd/frontend.c
index c57e122ee33..d8ca40d6a80 100644
--- a/sbin/slaacd/frontend.c
+++ b/sbin/slaacd/frontend.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: frontend.c,v 1.16 2018/05/17 11:51:27 florian Exp $	*/
+/*	$OpenBSD: frontend.c,v 1.17 2018/05/17 13:39:00 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -674,7 +674,9 @@ handle_route_message(struct rt_msghdr *rtm, struct sockaddr **rti_info)
 	struct if_msghdr		*ifm;
 	struct imsg_proposal_ack	 proposal_ack;
 	struct imsg_del_addr		 del_addr;
+	struct imsg_del_route		 del_route;
 	struct sockaddr_rtlabel		*rl;
+	struct in6_addr			*in6;
 	int64_t				 id, pid;
 	int				 flags, xflags, if_index;
 	char				 ifnamebuf[IFNAMSIZ];
@@ -729,6 +731,46 @@ handle_route_message(struct rt_msghdr *rtm, struct sockaddr **rti_info)
 			    ifm->ifm_index);
 		}
 		break;
+	case RTM_DELETE:
+		ifm = (struct if_msghdr *)rtm;
+		if ((rtm->rtm_addrs & (RTA_DST | RTA_GATEWAY | RTA_LABEL)) !=
+		    (RTA_DST | RTA_GATEWAY | RTA_LABEL))
+			break;
+		if (rti_info[RTAX_DST]->sa_family != AF_INET6)
+			break;
+		if (!IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *)
+		    rti_info[RTAX_DST])->sin6_addr))
+			break;
+		if (rti_info[RTAX_GATEWAY]->sa_family != AF_INET6)
+			break;
+		if (rti_info[RTAX_LABEL]->sa_len !=
+		    sizeof(struct sockaddr_rtlabel))
+			break;
+
+		rl = (struct sockaddr_rtlabel *)rti_info[RTAX_LABEL];
+		if (strcmp(rl->sr_label, SLAACD_RTA_LABEL) != 0)
+			break;
+
+		if_name = if_indextoname(ifm->ifm_index, ifnamebuf);
+
+		del_route.if_index = ifm->ifm_index;
+		memcpy(&del_route.gw, rti_info[RTAX_GATEWAY],
+		    sizeof(del_route.gw));
+		in6 = &del_route.gw.sin6_addr;
+		/* XXX from route(8) p_sockaddr() */
+		if (IN6_IS_ADDR_LINKLOCAL(in6) ||
+		    IN6_IS_ADDR_MC_LINKLOCAL(in6) ||
+		    IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
+			del_route.gw.sin6_scope_id =
+			    (u_int32_t)ntohs(*(u_short *) &in6->s6_addr[2]);
+			*(u_short *)&in6->s6_addr[2] = 0;
+		}
+		frontend_imsg_compose_engine(IMSG_DEL_ROUTE,
+		    0, 0, &del_route, sizeof(del_route));
+		log_debug("RTM_DELETE: %s[%u]", if_name,
+		    ifm->ifm_index);
+
+		break;
 	case RTM_PROPOSAL:
 		ifm = (struct if_msghdr *)rtm;
 		if_name = if_indextoname(ifm->ifm_index, ifnamebuf);
diff --git a/sbin/slaacd/slaacd.c b/sbin/slaacd/slaacd.c
index 8b5499f97af..8a405b5ca94 100644
--- a/sbin/slaacd/slaacd.c
+++ b/sbin/slaacd/slaacd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: slaacd.c,v 1.21 2018/05/17 11:52:04 florian Exp $	*/
+/*	$OpenBSD: slaacd.c,v 1.22 2018/05/17 13:39:00 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -82,6 +82,7 @@ const char* imsg_type_name[] = {
 	"IMSG_PROPOSAL_ACK",
 	"IMSG_CONFIGURE_ADDRESS",
 	"IMSG_DEL_ADDRESS",
+	"IMSG_DEL_ROUTE",
 	"IMSG_FAKE_ACK",
 	"IMSG_CONFIGURE_DFR",
 	"IMSG_WITHDRAW_DFR",
@@ -308,7 +309,8 @@ main(int argc, char *argv[])
 		fatal("route socket");
 
 	rtfilter = ROUTE_FILTER(RTM_IFINFO) | ROUTE_FILTER(RTM_NEWADDR) |
-	    ROUTE_FILTER(RTM_DELADDR) | ROUTE_FILTER(RTM_PROPOSAL);
+	    ROUTE_FILTER(RTM_DELADDR) | ROUTE_FILTER(RTM_PROPOSAL) |
+	    ROUTE_FILTER(RTM_DELETE);
 	if (setsockopt(frontend_routesock, PF_ROUTE, ROUTE_MSGFILTER,
 	    &rtfilter, sizeof(rtfilter)) < 0)
 		fatal("setsockopt(ROUTE_MSGFILTER)");
diff --git a/sbin/slaacd/slaacd.h b/sbin/slaacd/slaacd.h
index 0efbe0cb1fb..923b5ec9f40 100644
--- a/sbin/slaacd/slaacd.h
+++ b/sbin/slaacd/slaacd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: slaacd.h,v 1.15 2018/05/17 11:51:27 florian Exp $	*/
+/*	$OpenBSD: slaacd.h,v 1.16 2018/05/17 13:39:00 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -70,6 +70,7 @@ enum imsg_type {
 	IMSG_PROPOSAL_ACK,
 	IMSG_CONFIGURE_ADDRESS,
 	IMSG_DEL_ADDRESS,
+	IMSG_DEL_ROUTE,
 	IMSG_FAKE_ACK,
 	IMSG_CONFIGURE_DFR,
 	IMSG_WITHDRAW_DFR,
@@ -185,6 +186,11 @@ struct imsg_del_addr {
 	struct sockaddr_in6	addr;
 };
 
+struct imsg_del_route {
+	uint32_t		if_index;
+	struct sockaddr_in6	gw;
+};
+
 struct imsg_proposal_ack {
 	int64_t		 id;
 	pid_t		 pid;