From: Roy Marples <roy@marples.name>
Date: Tue, 21 May 2013 09:24:49 +0000 (+0000)
Subject: Don't actually remove unreachable routers and prefixes from the routing table.
X-Git-Tag: v5.99.7~52
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=99d2575328ed914f44dda510a35ff22044356263;p=thirdparty%2Fdhcpcd.git

Don't actually remove unreachable routers and prefixes from the routing table.
Instead we just change the interface if they are reachable via another one.
---

diff --git a/ipv6.c b/ipv6.c
index 9fb159ea..cae5c96f 100644
--- a/ipv6.c
+++ b/ipv6.c
@@ -641,12 +641,36 @@ ipv6_removesubnet(const struct interface *ifp, struct ipv6_addr *addr)
 	(IN6_ARE_ADDR_EQUAL(&((rtp)->dest), &in6addr_any) &&		      \
 	    IN6_ARE_ADDR_EQUAL(&((rtp)->net), &in6addr_any))
 
+static void
+ipv6_buildroutes1(struct rt6head *dnr, int expired)
+{
+	struct rt6 *rt;
+	struct ra *rap;
+	struct ipv6_addr *addr;
+
+	TAILQ_FOREACH(rap, &ipv6_routers, next) {
+		if (rap->expired != expired)
+			continue;
+		if (options & DHCPCD_IPV6RA_OWN) {
+			TAILQ_FOREACH(addr, &rap->addrs, next) {
+				if (!addr->onlink)
+					continue;
+				rt = make_prefix(rap->iface, rap, addr);
+				if (rt)
+					TAILQ_INSERT_TAIL(dnr, rt, next);
+			}
+		}
+		rt = make_router(rap);
+		if (rt)
+			TAILQ_INSERT_TAIL(dnr, rt, next);
+	}
+}
+
 void
 ipv6_buildroutes(void)
 {
 	struct rt6head dnr, *nrs;
 	struct rt6 *rt, *rtn, *or;
-	struct ra *rap;
 	struct ipv6_addr *addr;
 	const struct interface *ifp;
 	const struct dhcp6_state *d6_state;
@@ -656,6 +680,12 @@ ipv6_buildroutes(void)
 		return;
 
 	TAILQ_INIT(&dnr);
+
+	/* First add reachable routers and their prefixes */
+	ipv6_buildroutes1(&dnr, 0);
+
+	/* We have no way of knowing if prefixes added by DHCP are reachable
+	 * or not, so we have to assume they are */
 	TAILQ_FOREACH(ifp, ifaces, next) {
 		d6_state = D6_CSTATE(ifp);
 		if (d6_state &&
@@ -671,22 +701,11 @@ ipv6_buildroutes(void)
 			}
 		}
 	}
-	TAILQ_FOREACH(rap, &ipv6_routers, next) {
-		if (options & DHCPCD_IPV6RA_OWN) {
-			TAILQ_FOREACH(addr, &rap->addrs, next) {
-				if (!addr->onlink)
-					continue;
-				rt = make_prefix(rap->iface, rap, addr);
-				if (rt)
-					TAILQ_INSERT_TAIL(&dnr, rt, next);
-			}
-		}
-		if (!rap->expired) {
-			rt = make_router(rap);
-			if (rt)
-				TAILQ_INSERT_TAIL(&dnr, rt, next);
-		}
-	}
+
+	/* Add our non-reachable routers and prefixes
+	 * Unsure if this is needed, but it's a close match to kernel
+	 * behaviour */
+	ipv6_buildroutes1(&dnr, 1);
 
 	nrs = malloc(sizeof(*nrs));
 	if (nrs == NULL) {
diff --git a/ipv6ns.c b/ipv6ns.c
index 5a182f82..a0f23843 100644
--- a/ipv6ns.c
+++ b/ipv6ns.c
@@ -209,6 +209,7 @@ static void
 ipv6ns_unreachable(void *arg)
 {
 	struct ra *rap = arg;
+	struct timeval tv;
 
 	/* We could add an unreachable flag and persist the information,
 	 * but that is more effort than it's probably worth. */
@@ -217,6 +218,16 @@ ipv6ns_unreachable(void *arg)
 	rap->expired = 1;
 	ipv6_buildroutes();
 	script_runreason(rap->iface, "ROUTERADVERT"); /* XXX not RA */
+
+	/* We should still test if it's reachable or not so
+	 * incase it comes back to life and it's preferable. */
+	if (rap->reachable) {
+		ms_to_tv(&tv, rap->reachable);
+	} else {
+		tv.tv_sec = REACHABLE_TIME;
+		tv.tv_usec = 0;
+	}
+	eloop_timeout_add_tv(&tv, ipv6ns_proberouter, rap);
 }
 
 #ifdef LISTEN_DAD
@@ -626,6 +637,13 @@ ipv6ns_handledata(__unused void *arg)
 	}
 
 	if (is_solicited) {
+		if (rap->expired) {
+			rap->expired = 0;
+			syslog(LOG_INFO, "%s: %s is reachable again",
+				ifp->name, sfrom);
+			ipv6_buildroutes();
+			script_runreason(rap->iface, "ROUTERADVERT"); /* XXX */
+		}
 		rap->nsprobes = 0;
 		if (rap->reachable) {
 			ms_to_tv(&tv, rap->reachable);