Add $ipv6_cpe_wanif to enable functionality required for IPv6 CPE

(r225485).  When setting an interface name to it, the following
configurations will be enabled:

 1. "no_radr" is set to all IPv6 interfaces automatically.

 2. "-no_radr accept_rtadv" will be set only for $ipv6_cpe_wanif.  This is
    done just before evaluating $ifconfig_IF_ipv6 in the rc.d scripts (this
    means you can manually supersede this configuration if necessary).

 3. The node will add RA-sending routers to the default router list
    even if net.inet6.ip6.forwarding=1.

This mode is added to conform to RFC 6204 (a router which connects
the end-user network to a service provider network).  To enable
packet forwarding, you still need to set ipv6_gateway_enable=YES.

Note that accepting router entries into the default router list when
packet forwarding capability and a routing daemon are enabled can
result in messing up the routing table.  To minimize such unexpected
behaviors, "no_radr" is set on all interfaces but $ipv6_cpe_wanif.

Approved by:	re (bz)

etc/defaults/rc.conf

@@ -468,6 +468,9 @@ ipv6_static_routes=""		# Set to static route list (or leave empty).
 				#  route toward loopback interface.
 #ipv6_route_xxx="fec0:0000:0000:0006:: -prefixlen 64 ::1"
 ipv6_gateway_enable="NO"	# Set to YES if this host will be a gateway.
+ipv6_cpe_wanif="NO"		# Set to the upstram interface name if this
+				# node will work as a router to forward IPv6
+				# packets not explicitly addressed to itself.
 ipv6_privacy="NO"		# Use privacy address on RA-receiving IFs
 				# (RFC 4193)
 

etc/network.subr

@@ -113,6 +113,12 @@ ifconfig_up()
 			;;
 		esac
 
+		case $ipv6_cpe_wanif in
+		$1)
+			_ipv6_opts="${_ipv6_opts} -no_radr accept_rtadv"
+		;;
+		esac
+
 		if [ -n "${_ipv6_opts}" ]; then
 			ifconfig $1 inet6 ${_ipv6_opts}
 		fi

etc/rc.d/netoptions

@@ -106,6 +106,19 @@ netoptions_inet6()
 		${SYSCTL} net.inet6.ip6.use_tempaddr=1 >/dev/null
 		${SYSCTL} net.inet6.ip6.prefer_tempaddr=1 >/dev/null
 	fi
+
+	case $ipv6_cpe_wanif in
+	""|[Nn][Oo]|[Nn][Oo][Nn][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Oo][Ff][Ff]|0)
+		${SYSCTL} net.inet6.ip6.no_radr=0 >/dev/null
+		${SYSCTL} net.inet6.ip6.rfc6204w3=0 >/dev/null
+	;;
+	*)	
+		netoptions_init
+		echo -n " IPv6 CPE WANIF=${ipv6_cpe_wanif}"
+		${SYSCTL} net.inet6.ip6.no_radr=1 >/dev/null
+		${SYSCTL} net.inet6.ip6.rfc6204w3=1 >/dev/null
+	;;
+	esac
 }
 
 load_rc_config $name

sys/netinet6/in6.h

@@ -614,7 +614,9 @@ struct ip6_mtuinfo {
 #define	IPV6CTL_NO_RADR		48	/* No defroute from RA */
 #define	IPV6CTL_NORBIT_RAIF	49	/* Disable R-bit in NA on RA
 					 * receiving IF. */
-#define	IPV6CTL_MAXID		50
+#define	IPV6CTL_RFC6204W3	50	/* Accept defroute even when forwarding
+					   enabled */
+#define	IPV6CTL_MAXID		51
 #endif /* __BSD_VISIBLE */
 
 /*

sys/netinet6/in6_proto.c

@@ -399,6 +399,7 @@ VNET_DEFINE(int, ip6_defmcasthlim) = IPV6_DEFAULT_MULTICAST_HOPS;
 VNET_DEFINE(int, ip6_accept_rtadv) = 0;
 VNET_DEFINE(int, ip6_no_radr) = 0;
 VNET_DEFINE(int, ip6_norbit_raif) = 0;
+VNET_DEFINE(int, ip6_rfc6204w3) = 0;
 VNET_DEFINE(int, ip6_maxfragpackets);	/* initialized in frag6.c:frag6_init() */
 VNET_DEFINE(int, ip6_maxfrags);		/* initialized in frag6.c:frag6_init() */
 VNET_DEFINE(int, ip6_log_interval) = 5;
@@ -536,6 +537,10 @@ SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_NORBIT_RAIF, norbit_raif, CTLFLAG_RW,
 	&VNET_NAME(ip6_norbit_raif), 0,
 	"Always set 0 to R flag in ICMPv6 NA messages when accepting RA"
 	" on the interface.");
+SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_RFC6204W3, rfc6204w3,
+	CTLFLAG_RW, &VNET_NAME(ip6_rfc6204w3), 0,
+	"Accept the default router list from ICMPv6 RA messages even "
+	"when packet forwarding enabled.");
 SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
 	&VNET_NAME(ip6_keepfaith), 0, "");
 SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_LOG_INTERVAL, log_interval,

sys/netinet6/ip6_var.h

@@ -319,6 +319,8 @@ VNET_DECLARE(int, ip6_accept_rtadv);	/* Acts as a host not a router */
 VNET_DECLARE(int, ip6_no_radr);		/* No defroute from RA */
 VNET_DECLARE(int, ip6_norbit_raif);	/* Disable R-bit in NA on RA
 					 * receiving IF. */
+VNET_DECLARE(int, ip6_rfc6204w3);	/* Accept defroute from RA even when
+					   forwarding enabled */
 VNET_DECLARE(int, ip6_keepfaith);	/* Firewall Aided Internet Translator */
 VNET_DECLARE(int, ip6_log_interval);
 VNET_DECLARE(time_t, ip6_log_time);
@@ -332,6 +334,7 @@ VNET_DECLARE(int, ip6_dad_count);	/* DupAddrDetectionTransmits */
 #define	V_ip6_accept_rtadv		VNET(ip6_accept_rtadv)
 #define	V_ip6_no_radr			VNET(ip6_no_radr)
 #define	V_ip6_norbit_raif		VNET(ip6_norbit_raif)
+#define	V_ip6_rfc6204w3			VNET(ip6_rfc6204w3)
 #define	V_ip6_keepfaith			VNET(ip6_keepfaith)
 #define	V_ip6_log_interval		VNET(ip6_log_interval)
 #define	V_ip6_log_time			VNET(ip6_log_time)

sys/netinet6/nd6_rtr.c

@@ -269,11 +269,13 @@ nd6_ra_input(struct mbuf *m, int off, int icmp6len)
 	dr0.rtaddr = saddr6;
 	dr0.flags  = nd_ra->nd_ra_flags_reserved;
 	/*
-	 * Effectively-disable the route in the RA packet
-	 * when ND6_IFF_NO_RADR on the receiving interface or
-	 * ip6.forwarding=1.
+	 * Effectively-disable routes from RA messages when
+	 * ND6_IFF_NO_RADR enabled on the receiving interface or
+	 * (ip6.forwarding == 1 && ip6.rfc6204w3 != 1).
 	 */
-	if (ndi->flags & ND6_IFF_NO_RADR || V_ip6_forwarding)
+	if (ndi->flags & ND6_IFF_NO_RADR)
+		dr0.rtlifetime = 0;
+	else if (V_ip6_forwarding && !V_ip6_rfc6204w3)
 		dr0.rtlifetime = 0;
 	else
 		dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);