[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>

5 files changed, 36 insertions, 1 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 88efed0a533f..35aed1c6dd98 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/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.
 
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c609cc702375..1263d8cb3c18 100644
--- a/include/linux/ipv6.h
+++ b/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
 };
 
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index f49488ffefef..8ad4beab2888 100644
--- a/include/linux/sysctl.h
+++ b/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
 };
 
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e7add61e6e39..eb82cd5df8c6 100644
--- a/net/ipv6/addrconf.c
+++ b/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 */
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 1f6256909674..dfa20d3be9b6 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1214,11 +1214,13 @@ skip_defrtr:
         }
 
 #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);
                 }