[IPV6]: ROUTE: Add accept_ra_rt_info_max_plen sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ip-sysctl.txt

@@ -729,6 +729,15 @@ accept_ra_pinfo - BOOLEAN
 	Functional default: enabled if accept_ra is enabled.
 			    disabled if accept_ra is disabled.
 
+accept_ra_rt_info_max_plen - INTEGER
+	Maximum prefix length of Route Information in RA.
+
+	Route Information w/ prefix larger than or equal to this
+	variable shall be ignored.
+
+	Functional default: 0 if accept_ra_rtr_pref is enabled.
+			    -1 if accept_ra_rtr_pref is disabled.
+
 accept_ra_rtr_pref - BOOLEAN
 	Accept Router Preference in RA.
 

include/linux/ipv6.h

@@ -150,6 +150,9 @@ struct ipv6_devconf {
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	__s32		accept_ra_rtr_pref;
 	__s32		rtr_probe_interval;
+#ifdef CONFIG_IPV6_ROUTE_INFO
+	__s32		accept_ra_rt_info_max_plen;
+#endif
 #endif
 	void		*sysctl;
 };
@@ -177,6 +180,7 @@ enum {
 	DEVCONF_ACCEPT_RA_PINFO,
 	DEVCONF_ACCEPT_RA_RTR_PREF,
 	DEVCONF_RTR_PROBE_INTERVAL,
+	DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN,
 	DEVCONF_MAX
 };
 

include/linux/sysctl.h

@@ -535,6 +535,7 @@ enum {
 	NET_IPV6_ACCEPT_RA_PINFO=19,
 	NET_IPV6_ACCEPT_RA_RTR_PREF=20,
 	NET_IPV6_RTR_PROBE_INTERVAL=21,
+	NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN=22,
 	__NET_IPV6_MAX
 };
 

net/ipv6/addrconf.c

@@ -170,6 +170,9 @@ struct ipv6_devconf ipv6_devconf = {
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	.accept_ra_rtr_pref	= 1,
 	.rtr_probe_interval	= 60 * HZ,
+#ifdef CONFIG_IPV6_ROUTE_INFO
+	.accept_ra_rt_info_max_plen = 0,
+#endif
 #endif
 };
 
@@ -197,6 +200,9 @@ static struct ipv6_devconf ipv6_devconf_dflt = {
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	.accept_ra_rtr_pref	= 1,
 	.rtr_probe_interval	= 60 * HZ,
+#ifdef CONFIG_IPV6_ROUTE_INFO
+	.accept_ra_rt_info_max_plen = 0,
+#endif
 #endif
 };
 
@@ -3133,6 +3139,9 @@ static void inline ipv6_store_devconf(struct ipv6_devconf *cnf,
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	array[DEVCONF_ACCEPT_RA_RTR_PREF] = cnf->accept_ra_rtr_pref;
 	array[DEVCONF_RTR_PROBE_INTERVAL] = cnf->rtr_probe_interval;
+#ifdef CONFIV_IPV6_ROUTE_INFO
+	array[DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN] = cnf->accept_ra_rt_info_max_plen;
+#endif
 #endif
 }
 
@@ -3620,6 +3629,16 @@ static struct addrconf_sysctl_table
 			.proc_handler	=	&proc_dointvec_jiffies,
 			.strategy	=	&sysctl_jiffies,
 		},
+#ifdef CONFIV_IPV6_ROUTE_INFO
+		{
+			.ctl_name	=	NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN,
+			.procname	=	"accept_ra_rt_info_max_plen",
+			.data		=	&ipv6_devconf.accept_ra_rt_info_max_plen,
+			.maxlen		=	sizeof(int),
+			.mode		=	0644,
+			.proc_handler	=	&proc_dointvec,
+		},
+#endif
 #endif
 		{
 			.ctl_name	=	0,	/* sentinel */

net/ipv6/ndisc.c

@@ -1214,11 +1214,13 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	}
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
-	if (ndopts.nd_opts_ri) {
+	if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
 		struct nd_opt_hdr *p;
 		for (p = ndopts.nd_opts_ri;
 		     p;
 		     p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
+			if (((struct route_info *)p)->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
+				continue;
 			rt6_route_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3,
 				      &skb->nh.ipv6h->saddr);
 		}