From: Roy Marples <roy@marples.name>
Date: Tue, 5 Mar 2019 00:28:36 +0000 (+0000)
Subject: route: Remove kroutes and make froutes optional
X-Git-Tag: v8.0.0~69
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f3fef65c52ebe102f242ef6b79f45aef46d52d5;p=thirdparty%2Fdhcpcd.git

route: Remove kroutes and make froutes optional

This is an attempt to reduce the memory dhcpcd uses.
By removing kroutes and froutes from global context.

kroutes are generated at the start of rt_build and freed at
the end.
---

diff --git a/src/dhcp.c b/src/dhcp.c
index 73ca69f8..b85bce94 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -3648,15 +3648,9 @@ dhcp_init(struct interface *ifp)
 	const struct if_options *ifo;
 	uint8_t len;
 	char buf[(sizeof(ifo->clientid) - 1) * 3];
-	int r;
 
-	r = dhcp_initstate(ifp);
-	if (r == -1)
+	if (dhcp_initstate(ifp) == -1)
 		return -1;
-	else if (r == 1) {
-		/* Now is a good time to find IPv4 routes */
-		if_initrt(ifp->ctx, AF_INET);
-	}
 
 	state = D_STATE(ifp);
 	state->state = DHS_INIT;
diff --git a/src/dhcp6.c b/src/dhcp6.c
index da5242fd..390615ae 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -2830,7 +2830,6 @@ dhcp6_delegate_prefix(struct interface *ifp)
 	}
 
 	/* Now all addresses have been added, rebuild the routing table. */
-	if_initrt(ifp->ctx, AF_INET6);
 	rt_build(ifp->ctx, AF_INET6);
 }
 
@@ -2895,7 +2894,6 @@ dhcp6_find_delegates(struct interface *ifp)
 		state = D6_STATE(ifp);
 		state->state = DH6S_DELEGATED;
 		ipv6_addaddrs(&state->addrs);
-		if_initrt(ifp->ctx, AF_INET6);
 		rt_build(ifp->ctx, AF_INET6);
 		dhcp6_script_try_run(ifp, 1);
 	}
@@ -3133,7 +3131,6 @@ dhcp6_bind(struct interface *ifp, const char *op, const char *sfrom)
 		else
 			lognewinfo("%s: expire in %"PRIu32" seconds",
 			    ifp->name, state->expire);
-		if_initrt(ifp->ctx, AF_INET6);
 		rt_build(ifp->ctx, AF_INET6);
 		if (!timed_out)
 			dhcp6_writelease(ifp);
diff --git a/src/dhcpcd.h b/src/dhcpcd.h
index a09f40fb..df229fd3 100644
--- a/src/dhcpcd.h
+++ b/src/dhcpcd.h
@@ -138,8 +138,9 @@ struct dhcpcd_ctx {
 	struct if_head *ifaces;
 
 	rb_tree_t routes;	/* our routes */
-	rb_tree_t kroutes;	/* all kernel routes */
+#ifdef RT_FREE_ROUTE_TABLE
 	rb_tree_t froutes;	/* free routes for re-use */
+#endif
 
 	int pf_inet_fd;
 	void *priv;
diff --git a/src/if-bsd.c b/src/if-bsd.c
index 8d281b42..20981411 100644
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -657,15 +657,13 @@ if_copyrt(struct dhcpcd_ctx *ctx, struct rt *rt, const struct rt_msghdr *rtm)
 }
 
 int
-if_initrt(struct dhcpcd_ctx *ctx, int af)
+if_initrt(struct dhcpcd_ctx *ctx, rb_tree_t *kroutes, int af)
 {
 	struct rt_msghdr *rtm;
 	int mib[6];
 	size_t needed;
 	char *buf, *p, *end;
-	struct rt rt;
-
-	rt_headclear(&ctx->kroutes, af);
+	struct rt rt, *rtn;
 
 	mib[0] = CTL_NET;
 	mib[1] = PF_ROUTE;
@@ -688,10 +686,15 @@ if_initrt(struct dhcpcd_ctx *ctx, int af)
 	end = buf + needed;
 	for (p = buf; p < end; p += rtm->rtm_msglen) {
 		rtm = (void *)p;
-		if (if_copyrt(ctx, &rt, rtm) == 0) {
-			rt.rt_dflags |= RTDF_INIT;
-			rt_recvrt(RTM_ADD, &rt);
+		if (if_copyrt(ctx, &rt, rtm) != 0)
+			continue;
+		if ((rtn = rt_new(rt.rt_ifp)) == NULL) {
+			logerr(__func__);
+			break;
 		}
+		memcpy(rtn, &rt, sizeof(*rtn));
+		if (rb_tree_insert_node(kroutes, rtn) != rtn)
+			rt_free(rtn);
 	}
 	free(buf);
 	return 0;
diff --git a/src/if-linux.c b/src/if-linux.c
index 1e55d672..13f58c9b 100644
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -351,8 +351,8 @@ if_closesockets_os(struct dhcpcd_ctx *ctx)
 
 static int
 get_netlink(struct dhcpcd_ctx *ctx, struct iovec *iov,
-    struct interface *ifp, int fd, int flags,
-    int (*callback)(struct dhcpcd_ctx *, struct interface *, struct nlmsghdr *))
+    void *arg, int fd, int flags,
+    int (*callback)(struct dhcpcd_ctx *, void *, struct nlmsghdr *))
 {
 	struct sockaddr_nl nladdr = { .nl_pid = 0 };
 	struct msghdr msg = {
@@ -406,7 +406,7 @@ recv_again:
 			again = 0;
 			break;
 		}
-		if (callback && (r = callback(ctx, ifp, nlm)) != 0)
+		if (callback && (r = callback(ctx, arg, nlm)) != 0)
 			break;
 	}
 
@@ -822,9 +822,9 @@ if_handlelink(struct dhcpcd_ctx *ctx)
 }
 
 static int
-send_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp,
+send_netlink(struct dhcpcd_ctx *ctx, void *arg,
     int protocol, struct nlmsghdr *hdr,
-    int (*callback)(struct dhcpcd_ctx *, struct interface *, struct nlmsghdr *))
+    int (*callback)(struct dhcpcd_ctx *, void *, struct nlmsghdr *))
 {
 	int s, r;
 	struct sockaddr_nl snl = { .nl_family = AF_NETLINK };
@@ -854,7 +854,7 @@ send_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp,
 			.iov_len = sizeof(buf),
 		};
 
-		r = get_netlink(ctx, &riov, ifp, s, 0, callback);
+		r = get_netlink(ctx, &riov, arg, s, 0, callback);
 	} else
 		r = -1;
 	if (protocol != NETLINK_ROUTE)
@@ -1031,7 +1031,7 @@ genl_parse(struct nlmsghdr *nlm, struct nlattr *tb[], int maxtype)
 }
 
 static int
-_gnl_getfamily(__unused struct dhcpcd_ctx *ctx, __unused struct interface *ifp,
+_gnl_getfamily(__unused struct dhcpcd_ctx *ctx, __unused void *arg,
     struct nlmsghdr *nlm)
 {
 	struct nlattr *tb[CTRL_ATTR_FAMILY_ID + 1];
@@ -1066,9 +1066,10 @@ gnl_getfamily(struct dhcpcd_ctx *ctx, const char *name)
 }
 
 static int
-_if_getssid_nl80211(__unused struct dhcpcd_ctx *ctx, struct interface *ifp,
+_if_getssid_nl80211(__unused struct dhcpcd_ctx *ctx, void *arg,
     struct nlmsghdr *nlm)
 {
+	struct interface *ifp = arg;
 	struct nlattr *tb[NL80211_ATTR_BSS + 1];
 	struct nlattr *bss[NL80211_BSS_STATUS + 1];
 	uint32_t status;
@@ -1284,20 +1285,26 @@ if_route(unsigned char cmd, const struct rt *rt)
 }
 
 static int
-_if_initrt(struct dhcpcd_ctx *ctx, __unused struct interface *ifp,
+_if_initrt(struct dhcpcd_ctx *ctx, void *arg,
     struct nlmsghdr *nlm)
 {
-	struct rt rt;
+	struct rt rt, *rtn;
+	rb_tree_t *kroutes = arg;
 
-	if (if_copyrt(ctx, &rt, nlm) == 0) {
-		rt.rt_dflags |= RTDF_INIT;
-		rt_recvrt(RTM_ADD, &rt);
+	if (if_copyrt(ctx, &rt, nlm) != 0)
+		return 0;
+	if ((rtn = rt_new(rt.rt_ifp)) == NULL) {
+		logerr(__func__);
+		return 0;
 	}
+	memcpy(rtn, &rt, sizeof(*rtn));
+	if (rb_tree_insert_node(kroutes, rtn) != rtn)
+		rt_free(rtn);
 	return 0;
 }
 
 int
-if_initrt(struct dhcpcd_ctx *ctx, int af)
+if_initrt(struct dhcpcd_ctx *ctx, rb_tree_t *kroutes, int af)
 {
 	struct nlmr nlm = {
 	    .hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)),
@@ -1308,7 +1315,7 @@ if_initrt(struct dhcpcd_ctx *ctx, int af)
 	};
 
 	rt_headclear(&ctx->kroutes, af);
-	return send_netlink(ctx, NULL, NETLINK_ROUTE, &nlm.hdr, &_if_initrt);
+	return send_netlink(ctx, kroutes, NETLINK_ROUTE, &nlm.hdr, &_if_initrt);
 }
 
 
diff --git a/src/if.h b/src/if.h
index 1aac439b..0abde5b3 100644
--- a/src/if.h
+++ b/src/if.h
@@ -178,7 +178,7 @@ int if_handlelink(struct dhcpcd_ctx *);
 #endif
 
 int if_route(unsigned char, const struct rt *rt);
-int if_initrt(struct dhcpcd_ctx *, int);
+int if_initrt(struct dhcpcd_ctx *, rb_tree_t *, int);
 
 #ifdef INET
 int if_address(unsigned char, const struct ipv4_addr *);
diff --git a/src/ipv4.c b/src/ipv4.c
index cdccf6ce..e5ede166 100644
--- a/src/ipv4.c
+++ b/src/ipv4.c
@@ -767,10 +767,6 @@ ipv4_applyaddr(void *arg)
 	state->addr = ia;
 	state->added = STATE_ADDED;
 
-	/* Find any freshly added routes, such as the subnet route.
-	 * We do this because we cannot rely on recieving the kernel
-	 * notification right now via our link socket. */
-	if_initrt(ifp->ctx, AF_INET);
 	rt_build(ifp->ctx, AF_INET);
 
 #ifdef ARP
diff --git a/src/ipv4ll.c b/src/ipv4ll.c
index 5ae3d485..e4662ca7 100644
--- a/src/ipv4ll.c
+++ b/src/ipv4ll.c
@@ -218,7 +218,6 @@ test:
 		return;
 	}
 	timespecclear(&state->defend);
-	if_initrt(ifp->ctx, AF_INET);
 	rt_build(ifp->ctx, AF_INET);
 	arp_announce(astate);
 	script_runreason(ifp, "IPV4LL");
@@ -526,10 +525,6 @@ ipv4ll_recvrt(__unused int cmd, const struct rt *rt)
 	struct dhcpcd_ctx *ctx;
 	struct interface *ifp;
 
-	/* Ignore route init. */
-	if (rt->rt_dflags & RTDF_INIT)
-		return 0;
-
 	/* Only interested in default route changes. */
 	if (sa_is_unspecified(&rt->rt_dest))
 		return 0;
@@ -538,7 +533,6 @@ ipv4ll_recvrt(__unused int cmd, const struct rt *rt)
 	ctx = rt->rt_ifp->ctx;
 	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
 		if (IPV4LL_STATE_RUNNING(ifp)) {
-			if_initrt(ctx, AF_INET);
 			rt_build(ctx, AF_INET);
 			break;
 		}
diff --git a/src/ipv6.c b/src/ipv6.c
index ee626330..34c302fe 100644
--- a/src/ipv6.c
+++ b/src/ipv6.c
@@ -1604,7 +1604,6 @@ ipv6_startstatic(struct interface *ifp)
 	ia->prefix_pltime = ND6_INFINITE_LIFETIME;
 	ia->dadcallback = ipv6_staticdadcallback;
 	ipv6_addaddr(ia, NULL);
-	if_initrt(ifp->ctx, AF_INET6);
 	rt_build(ifp->ctx, AF_INET6);
 	if (run_script)
 		script_runreason(ifp, "STATIC6");
@@ -1646,8 +1645,6 @@ ipv6_start(struct interface *ifp)
 			ipv6_regentempifid(ifp);
 	}
 
-	/* Load existing routes */
-	if_initrt(ifp->ctx, AF_INET6);
 	return 0;
 }
 
@@ -1671,10 +1668,8 @@ ipv6_freedrop(struct interface *ifp, int drop)
 
 	ipv6_freedrop_addrs(&state->addrs, drop ? 2 : 0, NULL);
 	if (drop) {
-		if (ifp->ctx->ra_routers != NULL) {
-			if_initrt(ifp->ctx, AF_INET6);
+		if (ifp->ctx->ra_routers != NULL)
 			rt_build(ifp->ctx, AF_INET6);
-		}
 	} else {
 		/* Because we need to cache the addresses we don't control,
 		 * we only free the state on when NOT dropping addresses. */
diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index e148f862..51e69f8a 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -1213,11 +1213,6 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx,
 	ipv6_addtempaddrs(ifp, &rap->acquired);
 #endif
 
-	/* Find any freshly added routes, such as the subnet route.
-	 * We do this because we cannot rely on recieving the kernel
-	 * notification right now via our link socket. */
-	if_initrt(ifp->ctx, AF_INET6);
-
 	rt_build(ifp->ctx, AF_INET6);
 	if (ipv6nd_scriptrun(rap))
 		return;
diff --git a/src/route.c b/src/route.c
index d7cfe7ba..4d924f4b 100644
--- a/src/route.c
+++ b/src/route.c
@@ -131,6 +131,7 @@ const rb_tree_ops_t rt_compare_list_ops = {
 	.rbto_context = NULL
 };
 
+#ifdef RT_FREE_ROUTE_TABLE
 static int
 rt_compare_free(__unused void *context, const void *node1, const void *node2)
 {
@@ -144,14 +145,16 @@ static const rb_tree_ops_t rt_compare_free_ops = {
 	.rbto_node_offset = offsetof(struct rt, rt_tree),
 	.rbto_context = NULL
 };
+#endif
 
 void
 rt_init(struct dhcpcd_ctx *ctx)
 {
 
 	rb_tree_init(&ctx->routes, &rt_compare_os_ops);
-	rb_tree_init(&ctx->kroutes, &rt_compare_os_ops);
+#ifdef RT_FREE_ROUTE_TABLE
 	rb_tree_init(&ctx->froutes, &rt_compare_free_ops);
+#endif
 }
 
 static void
@@ -207,7 +210,9 @@ rt_headclear0(struct dhcpcd_ctx *ctx, rb_tree_t *rts, int af)
 	if (rts == NULL)
 		return;
 	assert(ctx != NULL);
+#ifdef RT_FREE_ROUTE_TABLE
 	assert(&ctx->froutes != rts);
+#endif
 
 	RB_TREE_FOREACH_SAFE(rt, rts, rtn) {
 		if (af != AF_UNSPEC &&
@@ -246,8 +251,9 @@ rt_dispose(struct dhcpcd_ctx *ctx)
 
 	assert(ctx != NULL);
 	rt_headfree(&ctx->routes);
-	rt_headfree(&ctx->kroutes);
+#ifdef RT_FREE_ROUTE_TABLE
 	rt_headfree(&ctx->froutes);
+#endif
 }
 
 struct rt *
@@ -256,9 +262,12 @@ rt_new0(struct dhcpcd_ctx *ctx)
 	struct rt *rt;
 
 	assert(ctx != NULL);
+#ifdef RT_FREE_ROUTE_TABLE
 	if ((rt = RB_TREE_MIN(&ctx->froutes)) != NULL)
 		rb_tree_remove_node(&ctx->froutes, rt);
-	else if ((rt = malloc(sizeof(*rt))) == NULL) {
+	else
+#endif
+	if ((rt = malloc(sizeof(*rt))) == NULL) {
 		logerr(__func__);
 		return NULL;
 	}
@@ -293,6 +302,7 @@ rt_new(struct interface *ifp)
 void
 rt_free(struct rt *rt)
 {
+#ifdef RT_FREE_ROUTE_TABLE
 	struct dhcpcd_ctx *ctx;
 
 	assert(rt != NULL);
@@ -301,6 +311,9 @@ rt_free(struct rt *rt)
 
 	ctx = rt->rt_ifp->ctx;
 	rb_tree_insert_node(&ctx->froutes, rt);
+#else
+	free(rt);
+#endif
 }
 
 void
@@ -318,27 +331,6 @@ rt_freeif(struct interface *ifp)
 			rt_free(rt);
 		}
 	}
-	RB_TREE_FOREACH_SAFE(rt, &ctx->kroutes, rtn) {
-		if (rt->rt_ifp == ifp) {
-			rb_tree_remove_node(&ctx->kroutes, rt);
-			rt_free(rt);
-		}
-	}
-}
-
-static void
-rt_kfree(struct rt *rt)
-{
-	struct dhcpcd_ctx *ctx;
-	struct rt *f;
-
-	assert(rt != NULL);
-	ctx = rt->rt_ifp->ctx;
-	f = rb_tree_find_node(&ctx->kroutes, rt);
-	if (f == NULL)
-		return;
-	rb_tree_remove_node(&ctx->kroutes, f);
-	rt_free(f);
 }
 
 /* If something other than dhcpcd removes a route,
@@ -357,11 +349,6 @@ rt_recvrt(int cmd, const struct rt *rt)
 
 	switch(cmd) {
 	case RTM_DELETE:
-		f = rb_tree_find_node(&ctx->kroutes, rt);
-		if (f != NULL) {
-			rb_tree_remove_node(&ctx->kroutes, f);
-			rt_free(f);
-		}
 		f = rb_tree_find_node(&ctx->routes, rt);
 		if (f != NULL) {
 			rb_tree_remove_node(&ctx->routes, f);
@@ -369,13 +356,6 @@ rt_recvrt(int cmd, const struct rt *rt)
 			rt_free(f);
 		}
 		break;
-	case RTM_ADD:
-		if ((f = rt_new(rt->rt_ifp)) == NULL)
-			break;
-		memcpy(f, rt, sizeof(*f));
-		if (rb_tree_insert_node(&ctx->kroutes, f) != f)
-			rt_free(f);
-		break;
 	}
 
 #if defined(IPV4LL) && defined(HAVE_ROUTE_METRIC)
@@ -385,7 +365,7 @@ rt_recvrt(int cmd, const struct rt *rt)
 }
 
 static bool
-rt_add(struct rt *nrt, struct rt *ort)
+rt_add(rb_tree_t *kroutes, struct rt *nrt, struct rt *ort)
 {
 	struct dhcpcd_ctx *ctx;
 	bool change;
@@ -412,7 +392,7 @@ rt_add(struct rt *nrt, struct rt *ort)
 
 	change = false;
 	if (ort == NULL) {
-		ort = rb_tree_find_node(&ctx->kroutes, nrt);
+		ort = rb_tree_find_node(kroutes, nrt);
 		if (ort != NULL &&
 		    ((ort->rt_flags & RTF_REJECT &&
 		      nrt->rt_flags & RTF_REJECT) ||
@@ -483,8 +463,6 @@ rt_add(struct rt *nrt, struct rt *ort)
 	if (ort != NULL) {
 		if (if_route(RTM_DELETE, ort) == -1 && errno != ESRCH)
 			logerr("if_route (DEL)");
-		else
-			rt_kfree(ort);
 	}
 #ifdef ROUTE_PER_GATEWAY
 	/* The OS allows many routes to the same dest with different gateways.
@@ -497,8 +475,11 @@ rt_add(struct rt *nrt, struct rt *ort)
 		}
 	}
 #endif
-	if (if_route(RTM_ADD, nrt) != -1)
+	if (if_route(RTM_ADD, nrt) != -1) {
+		if (ort != NULL)
+			memcpy(ort, nrt, sizeof(*ort));
 		return true;
+	}
 #ifdef HAVE_ROUTE_METRIC
 logerr:
 #endif
@@ -515,10 +496,6 @@ rt_delete(struct rt *rt)
 	retval = if_route(RTM_DELETE, rt) == -1 ? false : true;
 	if (!retval && errno != ENOENT && errno != ESRCH)
 		logerr(__func__);
-	/* Remove the route from our kernel table so we can add a
-	 * IPv4LL default route if possible. */
-	else
-		rt_kfree(rt);
 	return retval;
 }
 
@@ -534,7 +511,7 @@ rt_cmp(const struct rt *r1, const struct rt *r2)
 }
 
 static bool
-rt_doroute(struct rt *rt)
+rt_doroute(rb_tree_t *kroutes, struct rt *rt)
 {
 	struct dhcpcd_ctx *ctx;
 	struct rt *or;
@@ -551,20 +528,20 @@ rt_doroute(struct rt *rt)
 		    sa_cmp(&or->rt_ifa, &rt->rt_ifa) != 0) ||
 		    or->rt_mtu != rt->rt_mtu)
 		{
-			if (!rt_add(rt, or))
+			if (!rt_add(kroutes, rt, or))
 				return false;
 		}
 		rb_tree_remove_node(&ctx->routes, or);
 		rt_free(or);
 	} else {
 		if (rt->rt_dflags & RTDF_FAKE) {
-			or = rb_tree_find_node(&ctx->kroutes, rt);
+			or = rb_tree_find_node(kroutes, rt);
 			if (or == NULL)
 				return false;
 			if (!rt_cmp(rt, or))
 				return false;
 		} else {
-			if (!rt_add(rt, NULL))
+			if (!rt_add(kroutes, rt, NULL))
 				return false;
 		}
 	}
@@ -575,10 +552,11 @@ rt_doroute(struct rt *rt)
 void
 rt_build(struct dhcpcd_ctx *ctx, int af)
 {
-	rb_tree_t routes, added;
+	rb_tree_t kroutes, routes, added;
 	struct rt *rt, *rtn;
 	unsigned long long o;
 
+	rb_tree_init(&kroutes, &rt_compare_os_ops);
 	rb_tree_init(&routes, &rt_compare_list_ops);
 	rb_tree_init(&added, &rt_compare_os_ops);
 
@@ -597,6 +575,8 @@ rt_build(struct dhcpcd_ctx *ctx, int af)
 #endif
 	}
 
+	if_initrt(ctx, &kroutes, af);
+
 	RB_TREE_FOREACH_SAFE(rt, &routes, rtn) {
 		if (rt->rt_dest.sa_family != af &&
 		    rt->rt_gateway.sa_family != af)
@@ -604,7 +584,7 @@ rt_build(struct dhcpcd_ctx *ctx, int af)
 		/* Is this route already in our table? */
 		if (rb_tree_find_node(&added, rt) != NULL)
 			continue;
-		if (rt_doroute(rt)) {
+		if (rt_doroute(&kroutes, rt)) {
 			rb_tree_remove_node(&routes, rt);
 			if (rb_tree_insert_node(&added, rt) != rt) {
 				errno = EEXIST;
@@ -642,6 +622,8 @@ rt_build(struct dhcpcd_ctx *ctx, int af)
 		}
 	}
 
+
 getfail:
 	rt_headclear(&routes, AF_UNSPEC);
+	rt_headclear(&kroutes, AF_UNSPEC);
 }
diff --git a/src/route.h b/src/route.h
index 19b0d4c9..1786c506 100644
--- a/src/route.h
+++ b/src/route.h
@@ -75,7 +75,6 @@ struct rt {
 	unsigned int		rt_metric;
 #endif
 	unsigned int		rt_dflags;
-#define	RTDF_INIT		0x01		/* Generated by if_initrt() */
 #define	RTDF_IFA_ROUTE		0x02		/* Address generated route */
 #define	RTDF_FAKE		0x04		/* Maybe us on lease reboot  */
 #define	RTDF_RA			0x08		/* Router Advertisement */