root/net/sysctl_net.c

DEFINITIONS

1. net_ctl_header_lookup
2. is_seen
3. net_ctl_permissions
4. net_ctl_ro_header_perms
5. sysctl_net_init
6. sysctl_net_exit
7. sysctl_init
8. register_net_sysctl_table
9. register_net_sysctl_rotable
10. unregister_net_sysctl_table

/* -*- 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/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

#ifdef CONFIG_TR
#include <linux/if_tr.h>
#endif

static struct ctl_table_set *
net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
{
        return &namespaces->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_root *root,
                               struct nsproxy *nsproxy,
                               struct ctl_table *table)
{
        /* Allow network administrator to have same access as root. */
        if (capable(CAP_NET_ADMIN)) {
                int mode = (table->mode >> 6) & 7;
                return (mode << 6) | (mode << 3) | mode;
        }
        return table->mode;
}

static struct ctl_table_root net_sysctl_root = {
        .lookup = net_ctl_header_lookup,
        .permissions = net_ctl_permissions,
};

static int net_ctl_ro_header_perms(struct ctl_table_root *root,
                struct nsproxy *namespaces, struct ctl_table *table)
{
        if (namespaces->net_ns == &init_net)
                return table->mode;
        else
                return table->mode & ~0222;
}

static struct ctl_table_root net_sysctl_ro_root = {
        .permissions = net_ctl_ro_header_perms,
};

static int sysctl_net_init(struct net *net)
{
        setup_sysctl_set(&net->sysctls,
                         &net_sysctl_ro_root.default_set,
                         is_seen);
        return 0;
}

static void sysctl_net_exit(struct net *net)
{
        WARN_ON(!list_empty(&net->sysctls.list));
        return;
}

static struct pernet_operations sysctl_pernet_ops = {
        .init = sysctl_net_init,
        .exit = sysctl_net_exit,
};

static __init int sysctl_init(void)
{
        int ret;
        ret = register_pernet_subsys(&sysctl_pernet_ops);
        if (ret)
                goto out;
        register_sysctl_root(&net_sysctl_root);
        setup_sysctl_set(&net_sysctl_ro_root.default_set, NULL, NULL);
        register_sysctl_root(&net_sysctl_ro_root);
out:
        return ret;
}
subsys_initcall(sysctl_init);

struct ctl_table_header *register_net_sysctl_table(struct net *net,
        const struct ctl_path *path, struct ctl_table *table)
{
        struct nsproxy namespaces;
        namespaces = *current->nsproxy;
        namespaces.net_ns = net;
        return __register_sysctl_paths(&net_sysctl_root,
                                        &namespaces, path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl_table);

struct ctl_table_header *register_net_sysctl_rotable(const
                struct ctl_path *path, struct ctl_table *table)
{
        return __register_sysctl_paths(&net_sysctl_ro_root,
                        &init_nsproxy, path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);

void unregister_net_sysctl_table(struct ctl_table_header *header)
{
        unregister_sysctl_table(header);
}
EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);