DHCP6: Don't remove delegated prefix addresses on start or fail

In the event where an interface is first delegated and then
started, we don't want the reading of a lease file to remove the
delegated prefixes or addresses.
Neither do we want any DHCP6 failure to remove the delegated
addresses.

As such, we also can't test the actual DHCP6 state when building
routes. Instead, just change the test for a delegated prefix
or not so we can still prefer non delegated routes.

While here, fix reject routes being restored for privsep.

Fixes #333.

src/dhcp6.c

@@ -1187,14 +1187,14 @@ dhcp6_get_op(uint16_t type)
 }
 
 static void
-dhcp6_freedrop_addrs(struct interface *ifp, int drop,
+dhcp6_freedrop_addrs(struct interface *ifp, int drop, unsigned int notflags,
     const struct interface *ifd)
 {
 	struct dhcp6_state *state;
 
 	state = D6_STATE(ifp);
 	if (state) {
-		ipv6_freedrop_addrs(&state->addrs, drop, ifd);
+		ipv6_freedrop_addrs(&state->addrs, drop, notflags, ifd);
 		if (drop)
 			rt_build(ifp->ctx, AF_INET6);
 	}
@@ -1208,7 +1208,7 @@ static void dhcp6_delete_delegates(struct interface *ifp)
 	if (ifp->ctx->ifaces) {
 		TAILQ_FOREACH(ifp0, ifp->ctx->ifaces, next) {
 			if (ifp0 != ifp)
-				dhcp6_freedrop_addrs(ifp0, 1, ifp);
+				dhcp6_freedrop_addrs(ifp0, 1, 0, ifp);
 		}
 	}
 }
@@ -1779,7 +1779,7 @@ dhcp6_fail(struct interface *ifp)
 		dhcp6_leaseextend(ifp);
 		dhcp6_bind(ifp, NULL, NULL);
 	} else {
-		dhcp6_freedrop_addrs(ifp, 1, NULL);
+		dhcp6_freedrop_addrs(ifp, 1, IPV6_AF_ANYDELEGATED, NULL);
 #ifndef SMALL
 		dhcp6_delete_delegates(ifp);
 #endif
@@ -2732,7 +2732,7 @@ dhcp6_readlease(struct interface *ifp, int validate)
 	return bytes;
 
 ex:
-	dhcp6_freedrop_addrs(ifp, 0, NULL);
+	dhcp6_freedrop_addrs(ifp, 0, IPV6_AF_ANYDELEGATED, NULL);
 	dhcp_unlink(ifp->ctx, state->leasefile);
 	free(state->new);
 	state->new = NULL;
@@ -3082,7 +3082,6 @@ dhcp6_find_delegates(struct interface *ifp)
 	if (k) {
 		loginfox("%s: adding delegated prefixes", ifp->name);
 		state = D6_STATE(ifp);
-		state->state = DH6S_DELEGATED;
 		ipv6_addaddrs(&state->addrs);
 		rt_build(ifp->ctx, AF_INET6);
 		dhcp6_script_try_run(ifp, 1);
@@ -4153,7 +4152,7 @@ dhcp6_freedrop(struct interface *ifp, int drop, const char *reason)
 		}
 #endif
 
-		dhcp6_freedrop_addrs(ifp, drop, NULL);
+		dhcp6_freedrop_addrs(ifp, drop, 0, NULL);
 		free(state->old);
 		state->old = state->new;
 		state->old_len = state->new_len;

src/ipv6.c

@@ -615,18 +615,19 @@ ipv6_deletedaddr(struct ipv6_addr *ia)
 #ifdef PRIVSEP
 	if (!(ia->iface->ctx->options & DHCPCD_MANAGER))
 		ps_inet_closedhcp6(ia);
-#elif defined(SMALL)
-	UNUSED(ia);
-#else
+#endif
+#ifndef SMALL
 	/* NOREJECT is set if we delegated exactly the prefix to another
 	 * address.
 	 * This can only be one address, so just clear the flag.
 	 * This should ensure the reject route will be restored. */
 	if (ia->delegating_prefix != NULL)
 		ia->delegating_prefix->flags &= ~IPV6_AF_NOREJECT;
 #endif
-#else
-	UNUSED(ia);
+#endif
+
+#if !defined(DHCP6) || (!defined(PRIVSEP) && defined(SMALL))
+	UNUSED(ia)
 #endif
 }
 
@@ -1040,7 +1041,7 @@ ipv6_freeaddr(struct ipv6_addr *ia)
 
 void
 ipv6_freedrop_addrs(struct ipv6_addrhead *addrs, int drop,
-    const struct interface *ifd)
+    unsigned int notflags, const struct interface *ifd)
 {
 	struct ipv6_addr *ap, *apn, *apf;
 	struct timespec now;
@@ -1050,6 +1051,8 @@ ipv6_freedrop_addrs(struct ipv6_addrhead *addrs, int drop,
 #endif
 	timespecclear(&now);
 	TAILQ_FOREACH_SAFE(ap, addrs, next, apn) {
+		if (ap->flags & notflags)
+			continue;
 #ifndef SMALL
 		if (ifd != NULL &&
 		    (ap->delegating_prefix == NULL ||
@@ -1862,7 +1865,7 @@ ipv6_freedrop(struct interface *ifp, int drop)
 		free(cb);
 	}
 
-	ipv6_freedrop_addrs(&state->addrs, drop ? 2 : 0, NULL);
+	ipv6_freedrop_addrs(&state->addrs, drop ? 2 : 0, 0, NULL);
 	if (drop) {
 		if (ifp->ctx->ra_routers != NULL)
 			rt_build(ifp->ctx, AF_INET6);

src/ipv6.h

@@ -217,8 +217,8 @@ struct ipv6_addr {
 #define	IPV6_AF_ADDED		(1U << 3)
 #define	IPV6_AF_AUTOCONF	(1U << 4)
 #define	IPV6_AF_DADCOMPLETED	(1U << 5)
-#define	IPV6_AF_DELEGATED	(1U << 6)
-#define	IPV6_AF_DELEGATEDPFX	(1U << 7)
+#define	IPV6_AF_DELEGATED	(1U << 6)	// Delegated from prefix
+#define	IPV6_AF_DELEGATEDPFX	(1U << 7)	// Delegated prefix
 #define	IPV6_AF_NOREJECT	(1U << 8)
 #define	IPV6_AF_REQUEST		(1U << 9)
 #define	IPV6_AF_STATIC		(1U << 10)
@@ -231,6 +231,8 @@ struct ipv6_addr {
 #define	IPV6_AF_TEMPORARY	(1U << 16)
 #endif
 
+#define IPV6_AF_ANYDELEGATED	(IPV6_AF_DELEGATED | IPV6_AF_DELEGATEDPFX)
+
 struct ll_callback {
 	TAILQ_ENTRY(ll_callback) next;
 	void (*callback)(void *);
@@ -270,7 +272,7 @@ int ipv6_addaddr(struct ipv6_addr *, const struct timespec *);
 int ipv6_doaddr(struct ipv6_addr *, struct timespec *);
 ssize_t ipv6_addaddrs(struct ipv6_addrhead *addrs);
 void ipv6_deleteaddr(struct ipv6_addr *);
-void ipv6_freedrop_addrs(struct ipv6_addrhead *, int,
+void ipv6_freedrop_addrs(struct ipv6_addrhead *, int, unsigned int,
     const struct interface *);
 void ipv6_handleifa(struct dhcpcd_ctx *ctx, int, struct if_head *,
     const char *, const struct in6_addr *, uint8_t, int, pid_t);

src/ipv6nd.c

@@ -842,7 +842,7 @@ ipv6nd_removefreedrop_ra(struct ra *rap, int remove_ra, int drop_ra)
 	eloop_timeout_delete(rap->iface->ctx->eloop, NULL, rap);
 	if (remove_ra)
 		TAILQ_REMOVE(rap->iface->ctx->ra_routers, rap, next);
-	ipv6_freedrop_addrs(&rap->addrs, drop_ra, NULL);
+	ipv6_freedrop_addrs(&rap->addrs, drop_ra, 0, NULL);
 	routeinfohead_free(&rap->rinfos);
 	free(rap->data);
 	free(rap);