netconf: add support for IPv6 proxy_ndp

Need to be able to see changes to proxy NDP status on a per
interface basis via netlink (analog to proxy_arp).
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -442,6 +442,8 @@ static int inet6_netconf_msgsize_devconf(int type)
 	if (type == -1 || type == NETCONFA_MC_FORWARDING)
 		size += nla_total_size(4);
 #endif
+	if (type == -1 || type == NETCONFA_PROXY_NEIGH)
+		size += nla_total_size(4);
 
 	return size;
 }
@@ -475,6 +477,10 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 			devconf->mc_forwarding) < 0)
 		goto nla_put_failure;
 #endif
+	if ((type == -1 || type == NETCONFA_PROXY_NEIGH) &&
+	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0)
+		goto nla_put_failure;
+
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
@@ -509,6 +515,7 @@ void inet6_netconf_notify_devconf(struct net *net, int type, int ifindex,
 static const struct nla_policy devconf_ipv6_policy[NETCONFA_MAX+1] = {
 	[NETCONFA_IFINDEX]	= { .len = sizeof(int) },
 	[NETCONFA_FORWARDING]	= { .len = sizeof(int) },
+	[NETCONFA_PROXY_NEIGH]	= { .len = sizeof(int) },
 };
 
 static int inet6_netconf_get_devconf(struct sk_buff *in_skb,
@@ -4728,6 +4735,46 @@ int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static
+int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
+			      void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int *valp = ctl->data;
+	int ret;
+	int old, new;
+
+	old = *valp;
+	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+	new = *valp;
+
+	if (write && old != new) {
+		struct net *net = ctl->extra2;
+
+		if (!rtnl_trylock())
+			return restart_syscall();
+
+		if (valp == &net->ipv6.devconf_dflt->proxy_ndp)
+			inet6_netconf_notify_devconf(net, NETCONFA_PROXY_NEIGH,
+						     NETCONFA_IFINDEX_DEFAULT,
+						     net->ipv6.devconf_dflt);
+		else if (valp == &net->ipv6.devconf_all->proxy_ndp)
+			inet6_netconf_notify_devconf(net, NETCONFA_PROXY_NEIGH,
+						     NETCONFA_IFINDEX_ALL,
+						     net->ipv6.devconf_all);
+		else {
+			struct inet6_dev *idev = ctl->extra1;
+
+			inet6_netconf_notify_devconf(net, NETCONFA_PROXY_NEIGH,
+						     idev->dev->ifindex,
+						     &idev->cnf);
+		}
+		rtnl_unlock();
+	}
+
+	return ret;
+}
+
+
 static struct addrconf_sysctl_table
 {
 	struct ctl_table_header *sysctl_header;
@@ -4914,7 +4961,7 @@ static struct addrconf_sysctl_table
 			.data		= &ipv6_devconf.proxy_ndp,
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
-			.proc_handler	= proc_dointvec,
+			.proc_handler	= addrconf_sysctl_proxy_ndp,
 		},
 		{
 			.procname	= "accept_source_route",