Send a RA with router lifetime of 0 when an interface is removed from

the config.

RFC 4861, 6.2.5:
[...] the router SHOULD transmit one or more (but not more than
MAX_FINAL_RTR_ADVERTISEMENTS) final multicast Router Advertisements on
the interface with a Router Lifetime field of zero.

3 files changed, 83 insertions, 14 deletions

diff --git a/usr.sbin/rad/engine.c b/usr.sbin/rad/engine.c
index 25df94b0ba3..4f568e37ee7 100644
--- a/usr.sbin/rad/engine.c
+++ b/usr.sbin/rad/engine.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: engine.c,v 1.4 2018/07/11 14:03:13 florian Exp $	*/
+/*	$OpenBSD: engine.c,v 1.5 2018/07/11 17:32:05 florian Exp $	*/
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -43,8 +43,8 @@
 #include "rad.h"
 #include "engine.h"
 
-#define	MAX_RTR_ADV_INTERVAL	600
-#define	MIN_RTR_ADV_INTERVAL	200
+#define	MAX_RTR_ADV_INTERVAL		600
+#define	MIN_RTR_ADV_INTERVAL		200
 
 struct engine_iface {
 	TAILQ_ENTRY(engine_iface)	entry;
@@ -63,6 +63,7 @@ void			 parse_ra_rs(struct imsg_ra_rs *);
 void			 parse_ra(struct imsg_ra_rs *);
 void			 parse_rs(struct imsg_ra_rs *);
 void			 update_iface(uint32_t);
+void			 remove_iface(uint32_t);
 struct engine_iface	*find_engine_iface_by_id(uint32_t);
 void			 iface_timeout(int, short, void *);
 
@@ -147,6 +148,8 @@ engine(int debug, int verbose)
 	if (inet_pton(AF_INET6, "ff02::1", &all_nodes.sin6_addr) != 1)
 		fatal("inet_pton");
 
+	TAILQ_INIT(&engine_interfaces);
+
 	event_dispatch();
 
 	engine_shutdown();
@@ -224,6 +227,13 @@ engine_dispatch_frontend(int fd, short event, void *bula)
 			memcpy(&if_index, imsg.data, sizeof(if_index));
 			update_iface(if_index);
 			break;
+		case IMSG_REMOVE_IF:
+			if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof(if_index))
+				fatal("%s: IMSG_REMOVE_IF wrong length: %d",
+				    __func__, imsg.hdr.len);
+			memcpy(&if_index, imsg.data, sizeof(if_index));
+			remove_iface(if_index);
+			break;
 		case IMSG_CTL_LOG_VERBOSE:
 			/* Already checked by frontend. */
 			memcpy(&verbose, imsg.data, sizeof(verbose));
@@ -487,6 +497,7 @@ update_iface(uint32_t if_index)
 		engine_iface = calloc(1, sizeof(*engine_iface));
 		engine_iface->if_index = if_index;
 		evtimer_set(&engine_iface->timer, iface_timeout, engine_iface);
+		TAILQ_INSERT_TAIL(&engine_interfaces, engine_iface, entry);
 	}
 
 	tv.tv_sec = 0;
@@ -495,13 +506,40 @@ update_iface(uint32_t if_index)
 }
 
 void
+remove_iface(uint32_t if_index)
+{
+	struct engine_iface	*engine_iface;
+	struct imsg_send_ra	 send_ra;
+	char			 if_name[IF_NAMESIZE];
+
+	if ((engine_iface = find_engine_iface_by_id(if_index)) == NULL) {
+		/* we don't know this interface, frontend can delete it */
+		engine_imsg_compose_frontend(IMSG_REMOVE_IF, 0,
+		    &if_index, sizeof(if_index));
+		return;
+	}
+
+	send_ra.if_index = engine_iface->if_index;
+	memcpy(&send_ra.to, &all_nodes, sizeof(send_ra.to));
+
+	TAILQ_REMOVE(&engine_interfaces, engine_iface, entry);
+	evtimer_del(&engine_iface->timer);
+
+	if (if_indextoname(if_index, if_name) != NULL)
+		engine_imsg_compose_frontend(IMSG_SEND_RA, 0, &send_ra,
+		    sizeof(send_ra));
+	engine_imsg_compose_frontend(IMSG_REMOVE_IF, 0,
+	    &engine_iface->if_index, sizeof(engine_iface->if_index));
+	free(engine_iface);
+}
+
+void
 iface_timeout(int fd, short events, void *arg)
 {
 	struct engine_iface	*engine_iface = (struct engine_iface *)arg;
 	struct imsg_send_ra	 send_ra;
 	struct timeval		 tv;
 
-
 	tv.tv_sec = MIN_RTR_ADV_INTERVAL +
 	    arc4random_uniform(MAX_RTR_ADV_INTERVAL - MIN_RTR_ADV_INTERVAL);
 	tv.tv_usec = arc4random_uniform(1000000);
diff --git a/usr.sbin/rad/frontend.c b/usr.sbin/rad/frontend.c
index f6a7e7bee43..e3bc5376b7f 100644
--- a/usr.sbin/rad/frontend.c
+++ b/usr.sbin/rad/frontend.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: frontend.c,v 1.3 2018/07/11 14:03:13 florian Exp $	*/
+/*	$OpenBSD: frontend.c,v 1.4 2018/07/11 17:32:05 florian Exp $	*/
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -129,6 +129,7 @@ int			 in6_mask2prefixlen(struct in6_addr *);
 void			 get_interface_prefixes(struct ra_iface *,
 			     struct ra_prefix_conf *);
 void			 build_package(struct ra_iface *);
+void			 build_leaving_package(struct ra_iface *);
 void			 ra_output(struct ra_iface *, struct sockaddr_in6 *);
 
 struct rad_conf	*frontend_conf;
@@ -434,6 +435,7 @@ frontend_dispatch_engine(int fd, short event, void *bula)
 	struct imsg		 imsg;
 	struct imsg_send_ra	 send_ra;
 	struct ra_iface		*ra_iface;
+	uint32_t		 if_index;
 	int			 n, shut = 0;
 
 	if (event & EV_READ) {
@@ -465,6 +467,17 @@ frontend_dispatch_engine(int fd, short event, void *bula)
 			if (ra_iface)
 				ra_output(ra_iface, &send_ra.to);
 			break;
+		case IMSG_REMOVE_IF:
+			if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof(if_index))
+				fatal("%s: IMSG_REMOVE_IF wrong length: %d",
+				    __func__, imsg.hdr.len);
+			memcpy(&if_index, imsg.data, sizeof(if_index));
+			ra_iface = find_ra_iface_by_id(if_index);
+			if (ra_iface) {
+				TAILQ_REMOVE(&ra_interfaces, ra_iface, entry);
+				free_ra_iface(ra_iface);
+			}
+			break;
 		default:
 			log_debug("%s: error handling imsg %d", __func__,
 			    imsg.hdr.type);
@@ -631,7 +644,7 @@ merge_ra_interfaces(void)
 {
 	struct ra_iface_conf	*ra_iface_conf;
 	struct ra_prefix_conf	*ra_prefix_conf;
-	struct ra_iface		*ra_iface, *tmp;
+	struct ra_iface		*ra_iface;
 	uint32_t		 if_index;
 
 	TAILQ_FOREACH(ra_iface, &ra_interfaces, entry)
@@ -660,13 +673,6 @@ merge_ra_interfaces(void)
 		}
 	}
 
-	TAILQ_FOREACH_SAFE(ra_iface, &ra_interfaces, entry, tmp) {
-		if (ra_iface->removed) {
-			TAILQ_REMOVE(&ra_interfaces, ra_iface, entry);
-			free_ra_iface(ra_iface);
-		}
-	}
-
 	TAILQ_FOREACH(ra_iface, &ra_interfaces, entry) {
 		while ((ra_prefix_conf = SIMPLEQ_FIRST(&ra_iface->prefixes))
 		    != NULL) {
@@ -676,6 +682,14 @@ merge_ra_interfaces(void)
 		}
 		ra_iface->prefix_count = 0;
 
+		if (ra_iface->removed) {
+			log_debug("iface removed: %s", ra_iface->name);
+			build_leaving_package(ra_iface);
+			frontend_imsg_compose_engine(IMSG_REMOVE_IF, 0,
+			    &ra_iface->if_index, sizeof(ra_iface->if_index));
+			continue;
+		}
+
 		ra_iface_conf = find_ra_iface_conf(
 		    &frontend_conf->ra_iface_list, ra_iface->name);
 
@@ -898,6 +912,22 @@ build_package(struct ra_iface *ra_iface)
 }
 
 void
+build_leaving_package(struct ra_iface *ra_iface)
+{
+	struct nd_router_advert		 ra;
+	size_t				 len;
+
+	len = sizeof(ra);
+
+	memset(&ra, 0, sizeof(ra));
+
+	ra.nd_ra_type = ND_ROUTER_ADVERT;
+
+	memcpy(ra_iface->data, &ra, sizeof(ra));
+	ra_iface->datalen = sizeof(ra);
+}
+
+void
 ra_output(struct ra_iface *ra_iface, struct sockaddr_in6 *to)
 {
 
diff --git a/usr.sbin/rad/rad.h b/usr.sbin/rad/rad.h
index 445bf9c6f8b..ee9b32dc86a 100644
--- a/usr.sbin/rad/rad.h
+++ b/usr.sbin/rad/rad.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rad.h,v 1.4 2018/07/11 14:03:13 florian Exp $	*/
+/*	$OpenBSD: rad.h,v 1.5 2018/07/11 17:32:05 florian Exp $	*/
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -62,6 +62,7 @@ enum imsg_type {
 	IMSG_RA_RS,
 	IMSG_SEND_RA,
 	IMSG_UPDATE_IF,
+	IMSG_REMOVE_IF,
 	IMSG_SOCKET_IPC
 };