[NETNS][ICMP]: Make ctl tables for ICMP sysctls per-net.

Add some flesh to ipv4_sysctl_init_net and ipv4_sysctl_exit_net,
i.e. copy the table, alter .data pointers and register it per-net.

Other ipv4_table's sysctls are now global, but this is going to
change once sysctl permissions patches migrate from -mm tree to 
mainline in 2.6.26 merge window :)
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -17,6 +17,7 @@ struct netns_ipv4 {
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header	*forw_hdr;
 	struct ctl_table_header	*frags_hdr;
+	struct ctl_table_header	*ipv4_hdr;
 #endif
 	struct ipv4_devconf	*devconf_all;
 	struct ipv4_devconf	*devconf_dflt;

net/ipv4/sysctl_net_ipv4.c

@@ -403,38 +403,6 @@ static struct ctl_table ipv4_table[] = {
 		.proc_handler	= &ipv4_local_port_range,
 		.strategy	= &ipv4_sysctl_local_port_range,
 	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_ALL,
-		.procname	= "icmp_echo_ignore_all",
-		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_BROADCASTS,
-		.procname	= "icmp_echo_ignore_broadcasts",
-		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_IGNORE_BOGUS_ERROR_RESPONSES,
-		.procname	= "icmp_ignore_bogus_error_responses",
-		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR,
-		.procname	= "icmp_errors_use_inbound_ifaddr",
-		.data		= &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
 	{
 		.ctl_name	= NET_IPV4_ROUTE,
 		.procname	= "route",
@@ -585,22 +553,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec
 	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_RATELIMIT,
-		.procname	= "icmp_ratelimit",
-		.data		= &init_net.ipv4.sysctl_icmp_ratelimit,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
-	{
-		.ctl_name	= NET_IPV4_ICMP_RATEMASK,
-		.procname	= "icmp_ratemask",
-		.data		= &init_net.ipv4.sysctl_icmp_ratemask,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec
-	},
 	{
 		.ctl_name	= NET_TCP_TW_REUSE,
 		.procname	= "tcp_tw_reuse",
@@ -804,6 +756,58 @@ static struct ctl_table ipv4_table[] = {
 	{ .ctl_name = 0 }
 };
 
+static struct ctl_table ipv4_net_table[] = {
+	{
+		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_ALL,
+		.procname	= "icmp_echo_ignore_all",
+		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.ctl_name	= NET_IPV4_ICMP_ECHO_IGNORE_BROADCASTS,
+		.procname	= "icmp_echo_ignore_broadcasts",
+		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.ctl_name	= NET_IPV4_ICMP_IGNORE_BOGUS_ERROR_RESPONSES,
+		.procname	= "icmp_ignore_bogus_error_responses",
+		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.ctl_name	= NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR,
+		.procname	= "icmp_errors_use_inbound_ifaddr",
+		.data		= &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.ctl_name	= NET_IPV4_ICMP_RATELIMIT,
+		.procname	= "icmp_ratelimit",
+		.data		= &init_net.ipv4.sysctl_icmp_ratelimit,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{
+		.ctl_name	= NET_IPV4_ICMP_RATEMASK,
+		.procname	= "icmp_ratemask",
+		.data		= &init_net.ipv4.sysctl_icmp_ratemask,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+	{ }
+};
+
 struct ctl_path net_ipv4_ctl_path[] = {
 	{ .procname = "net", .ctl_name = CTL_NET, },
 	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
@@ -813,11 +817,49 @@ EXPORT_SYMBOL_GPL(net_ipv4_ctl_path);
 
 static __net_init int ipv4_sysctl_init_net(struct net *net)
 {
+	struct ctl_table *table;
+
+	table = ipv4_net_table;
+	if (net != &init_net) {
+		table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL);
+		if (table == NULL)
+			goto err_alloc;
+
+		table[0].data =
+			&net->ipv4.sysctl_icmp_echo_ignore_all;
+		table[1].data =
+			&net->ipv4.sysctl_icmp_echo_ignore_broadcasts;
+		table[2].data =
+			&net->ipv4.sysctl_icmp_ignore_bogus_error_responses;
+		table[3].data =
+			&net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr;
+		table[4].data =
+			&net->ipv4.sysctl_icmp_ratelimit;
+		table[5].data =
+			&net->ipv4.sysctl_icmp_ratemask;
+	}
+
+	net->ipv4.ipv4_hdr = register_net_sysctl_table(net,
+			net_ipv4_ctl_path, table);
+	if (net->ipv4.ipv4_hdr == NULL)
+		goto err_reg;
+
 	return 0;
+
+err_reg:
+	if (net != &init_net)
+		kfree(table);
+err_alloc:
+	return -ENOMEM;
 }
 
 static __net_exit void ipv4_sysctl_exit_net(struct net *net)
 {
+	struct ctl_table *table;
+
+	table = net->ipv4.ipv4_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
+	kfree(table);
 }
 
 static __net_initdata struct pernet_operations ipv4_sysctl_ops = {