text: /* -*- linux-c -*-
   * sysctl_net_core.c: sysctl interface to net core subsystem.
   *
   * Begun April 1, 1996, Mike Shaver.
   * Added /proc/sys/net/core directory entry (empty =) ). [MS]
   */
  
  #include <linux/mm.h>
  #include <linux/sysctl.h>
  #include <linux/module.h>
  #include <linux/socket.h>
  #include <linux/netdevice.h>
  #include <linux/ratelimit.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  
  #include <net/ip.h>
  #include <net/sock.h>
  
  static struct ctl_table net_core_table[] = {
  #ifdef CONFIG_NET
  	{
  		.procname	= "wmem_max",
  		.data		= &sysctl_wmem_max,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "rmem_max",
  		.data		= &sysctl_rmem_max,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "wmem_default",
  		.data		= &sysctl_wmem_default,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "rmem_default",
  		.data		= &sysctl_rmem_default,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "dev_weight",
  		.data		= &weight_p,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "netdev_max_backlog",
  		.data		= &netdev_max_backlog,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "message_cost",
  		.data		= &net_ratelimit_state.interval,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec_jiffies,
  	},
  	{
  		.procname	= "message_burst",
  		.data		= &net_ratelimit_state.burst,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "optmem_max",
  		.data		= &sysctl_optmem_max,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  #endif /* CONFIG_NET */
  	{
  		.procname	= "netdev_budget",
  		.data		= &netdev_budget,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{
  		.procname	= "warnings",
  		.data		= &net_msg_warn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{ }
  };
  
  static struct ctl_table netns_core_table[] = {
  	{
  		.procname	= "somaxconn",
  		.data		= &init_net.core.sysctl_somaxconn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec
  	},
  	{ }
  };
  
  __net_initdata struct ctl_path net_core_path[] = {
  	{ .procname = "net", },
  	{ .procname = "core", },
  	{ },
  };
  
  static __net_init int sysctl_core_net_init(struct net *net)
  {
  	struct ctl_table *tbl;
  
  	net->core.sysctl_somaxconn = SOMAXCONN;
  
  	tbl = netns_core_table;
  	if (!net_eq(net, &init_net)) {
  		tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
  		if (tbl == NULL)
  			goto err_dup;
  
  		tbl[0].data = &net->core.sysctl_somaxconn;
  	}
  
  	net->core.sysctl_hdr = register_net_sysctl_table(net,
  			net_core_path, tbl);
  	if (net->core.sysctl_hdr == NULL)
  		goto err_reg;
  
  	return 0;
  
  err_reg:
  	if (tbl != netns_core_table)
  		kfree(tbl);
  err_dup:
  	return -ENOMEM;
  }
  
  static __net_exit void sysctl_core_net_exit(struct net *net)
  {
  	struct ctl_table *tbl;
  
  	tbl = net->core.sysctl_hdr->ctl_table_arg;
  	unregister_net_sysctl_table(net->core.sysctl_hdr);
  	BUG_ON(tbl == netns_core_table);
  	kfree(tbl);
  }
  
  static __net_initdata struct pernet_operations sysctl_core_ops = {
  	.init = sysctl_core_net_init,
  	.exit = sysctl_core_net_exit,
  };
  
  static __init int sysctl_core_init(void)
  {
  	static struct ctl_table empty[1];
  
  	register_sysctl_paths(net_core_path, empty);
  	register_net_sysctl_rotable(net_core_path, net_core_table);
  	return register_pernet_subsys(&sysctl_core_ops);
  }
  
  fs_initcall(sysctl_core_init);
  