ipv4: Use math to point per net sysctls into the appropriate struct net.

	table = ipv4_net_table;

	if (!net_eq(net, &init_net)) {

		int i;

		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;

		table[6].data =

			&net->ipv4.sysctl_ping_group_range;

		table[7].data =

			&net->ipv4.sysctl_tcp_ecn;

		table[8].data =

			&net->ipv4.sysctl_local_ports.range;

		/* Update the variables to point into the current struct net */

		for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++)

			table[i].data += (void *)net - (void *)&init_net;

		/* Don't export sysctls to unprivileged users */

		if (net->user_ns != &init_user_ns)