/* -*- linux-c -*-

 * sysctl_net.c: sysctl interface to net subsystem.

 *

 * Begun April 1, 1996, Mike Shaver.

 * Added /proc/sys/net directories for each protocol family. [MS]

 *

 * Revision 1.2  1996/05/08  20:24:40  shaver

 * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and

 * NET_IPV4_IP_FORWARD.

 *

 *

 */

#include <linux/mm.h>

#include <linux/export.h>

#include <linux/sysctl.h>

#include <linux/nsproxy.h>

#include <net/sock.h>

#ifdef CONFIG_INET

#include <net/ip.h>

#endif

#ifdef CONFIG_NET

#include <linux/if_ether.h>

#endif

static struct ctl_table_set *

net_ctl_header_lookup(struct ctl_table_root *root)

{

	return &current->nsproxy->net_ns->sysctls;

}

static int is_seen(struct ctl_table_set *set)

{

	return &current->nsproxy->net_ns->sysctls == set;

}

/* Return standard mode bits for table entry. */

static int net_ctl_permissions(struct ctl_table_header *head,

			       struct ctl_table *table)

{

	struct net *net = container_of(head->set, struct net, sysctls);

	/* Allow network administrator to have same access as root. */

	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {

		int mode = (table->mode >> 6) & 7;

		return (mode << 6) | (mode << 3) | mode;

	}

	return table->mode;

}

static void net_ctl_set_ownership(struct ctl_table_header *head,

				  struct ctl_table *table,

				  kuid_t *uid, kgid_t *gid)

{

	struct net *net = container_of(head->set, struct net, sysctls);

	kuid_t ns_root_uid;

	kgid_t ns_root_gid;

	ns_root_uid = make_kuid(net->user_ns, 0);

	if (uid_valid(ns_root_uid))

		*uid = ns_root_uid;

	ns_root_gid = make_kgid(net->user_ns, 0);

	if (gid_valid(ns_root_gid))

		*gid = ns_root_gid;

}

static struct ctl_table_root net_sysctl_root = {

	.lookup = net_ctl_header_lookup,

	.permissions = net_ctl_permissions,

	.set_ownership = net_ctl_set_ownership,

};

static int __net_init sysctl_net_init(struct net *net)

{

	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);

	return 0;

}

static void __net_exit sysctl_net_exit(struct net *net)

{

	retire_sysctl_set(&net->sysctls);

}

static struct pernet_operations sysctl_pernet_ops = {

	.init = sysctl_net_init,

	.exit = sysctl_net_exit,

};

static struct ctl_table_header *net_header;

__init int net_sysctl_init(void)

{

	static struct ctl_table empty[1];

	int ret = -ENOMEM;

	/* Avoid limitations in the sysctl implementation by

	 * registering "/proc/sys/net" as an empty directory not in a

	 * network namespace.

	 */

	net_header = register_sysctl("net", empty);

	if (!net_header)

		goto out;

	ret = register_pernet_subsys(&sysctl_pernet_ops);

	if (ret)

		goto out1;

out:

	return ret;

out1:

	unregister_sysctl_table(net_header);

	net_header = NULL;

	goto out;

}

struct ctl_table_header *register_net_sysctl(struct net *net,

	const char *path, struct ctl_table *table)

{

	return __register_sysctl_table(&net->sysctls, path, table);

}

EXPORT_SYMBOL_GPL(register_net_sysctl);

void unregister_net_sysctl_table(struct ctl_table_header *header)

{

	unregister_sysctl_table(header);

}

EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);