This one will need to set the IPV4_DEVCONF_ALL(PROXY_ARP), but
there's no ways to get the net right in place, so we have to
pull one from the inet_ioctl's struct sock.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---

diff --git a/include/net/arp.h b/include/net/arp.h
index f026645..36482bf 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -11,7 +11,7 @@ extern struct neigh_table arp_tbl;
 
 extern void	arp_init(void);
 extern int	arp_find(unsigned char *haddr, struct sk_buff *skb);
-extern int	arp_ioctl(unsigned int cmd, void __user *arg);
+extern int	arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
 extern void     arp_send(int type, int ptype, __be32 dest_ip,
 			 struct net_device *dev, __be32 src_ip,
 			 unsigned char *dest_hw, unsigned char *src_hw, unsigned char *th);
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 7f8b27f..a69b0c6 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -798,7 +798,7 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		case SIOCDARP:
 		case SIOCGARP:
 		case SIOCSARP:
-			err = arp_ioctl(cmd, (void __user *)arg);
+			err = arp_ioctl(sk->sk_net, cmd, (void __user *)arg);
 			break;
 		case SIOCGIFADDR:
 		case SIOCSIFADDR:
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 48e7bf6..41a4d73 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -953,7 +953,7 @@ out_of_mem:
  *	Set (create) an ARP cache entry.
  */
 
-static int arp_req_set_proxy(struct net_device *dev, int on)
+static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
 {
 	if (dev == NULL) {
 		IPV4_DEVCONF_ALL(PROXY_ARP) = on;
@@ -966,7 +966,8 @@ static int arp_req_set_proxy(struct net_device *dev, int on)
 	return -ENXIO;
 }
 
-static int arp_req_set_public(struct arpreq *r, struct net_device *dev)
+static int arp_req_set_public(struct net *net, struct arpreq *r,
+		struct net_device *dev)
 {
 	__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
 	__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
@@ -985,17 +986,18 @@ static int arp_req_set_public(struct arpreq *r, struct net_device *dev)
 		return 0;
 	}
 
-	return arp_req_set_proxy(dev, 1);
+	return arp_req_set_proxy(net, dev, 1);
 }
 
-static int arp_req_set(struct arpreq *r, struct net_device * dev)
+static int arp_req_set(struct net *net, struct arpreq *r,
+		struct net_device * dev)
 {
 	__be32 ip;
 	struct neighbour *neigh;
 	int err;
 
 	if (r->arp_flags & ATF_PUBL)
-		return arp_req_set_public(r, dev);
+		return arp_req_set_public(net, r, dev);
 
 	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
 	if (r->arp_flags & ATF_PERM)
@@ -1081,7 +1083,8 @@ static int arp_req_get(struct arpreq *r, struct net_device *dev)
 	return err;
 }
 
-static int arp_req_delete_public(struct arpreq *r, struct net_device *dev)
+static int arp_req_delete_public(struct net *net, struct arpreq *r,
+		struct net_device *dev)
 {
 	__be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
 	__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
@@ -1092,17 +1095,18 @@ static int arp_req_delete_public(struct arpreq *r, struct net_device *dev)
 	if (mask)
 		return -EINVAL;
 
-	return arp_req_set_proxy(dev, 0);
+	return arp_req_set_proxy(net, dev, 0);
 }
 
-static int arp_req_delete(struct arpreq *r, struct net_device * dev)
+static int arp_req_delete(struct net *net, struct arpreq *r,
+		struct net_device * dev)
 {
 	int err;
 	__be32 ip;
 	struct neighbour *neigh;
 
 	if (r->arp_flags & ATF_PUBL)
-		return arp_req_delete_public(r, dev);
+		return arp_req_delete_public(net, r, dev);
 
 	ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
 	if (dev == NULL) {
@@ -1132,7 +1136,7 @@ static int arp_req_delete(struct arpreq *r, struct net_device * dev)
  *	Handle an ARP layer I/O control request.
  */
 
-int arp_ioctl(unsigned int cmd, void __user *arg)
+int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 {
 	int err;
 	struct arpreq r;
@@ -1180,10 +1184,10 @@ int arp_ioctl(unsigned int cmd, void __user *arg)
 
 	switch (cmd) {
 	case SIOCDARP:
-		err = arp_req_delete(&r, dev);
+		err = arp_req_delete(net, &r, dev);
 		break;
 	case SIOCSARP:
-		err = arp_req_set(&r, dev);
+		err = arp_req_set(net, &r, dev);
 		break;
 	case SIOCGARP:
 		err = arp_req_get(&r, dev);
-- 
1.5.3.4