ipv6: Add icmp_echo_ignore_multicast support for ICMPv6

IPv4 has icmp_echo_ignore_broadcast to prevent responding to broadcast pings.
IPv6 needs a similar mechanism.

v1->v2:
- Remove NET_IPV6_ICMP_ECHO_IGNORE_MULTICAST.

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 13 insertions, 0 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 2f45d2a3e3a3..fdc117de849c 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -847,6 +847,7 @@ static int __net_init inet6_net_init(struct net *net)
         net->ipv6.sysctl.bindv6only = 0;
         net->ipv6.sysctl.icmpv6_time = 1*HZ;
         net->ipv6.sysctl.icmpv6_echo_ignore_all = 0;
+        net->ipv6.sysctl.icmpv6_echo_ignore_multicast = 0;
         net->ipv6.sysctl.flowlabel_consistency = 1;
         net->ipv6.sysctl.auto_flowlabels = IP6_DEFAULT_AUTO_FLOW_LABELS;
         net->ipv6.sysctl.idgen_retries = 3;
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 802faa2fcc0e..0907bcede5e5 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -684,6 +684,10 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
         struct ipcm6_cookie ipc6;
         u32 mark = IP6_REPLY_MARK(net, skb->mark);
 
+        if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
+            net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
+                return;
+
         saddr = &ipv6_hdr(skb)->daddr;
 
         if (!ipv6_unicast_destination(skb) &&
@@ -1115,6 +1119,13 @@ static struct ctl_table ipv6_icmp_table_template[] = {
                 .mode           = 0644,
                 .proc_handler = proc_dointvec,
         },
+        {
+                .procname       = "echo_ignore_multicast",
+                .data           = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler = proc_dointvec,
+        },
         { },
 };
 
@@ -1129,6 +1140,7 @@ struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
         if (table) {
                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
                 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
+                table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
         }
         return table;
 }