summaryrefslogtreecommitdiff
path: root/fs/proc/proc_net.c
blob: 131f9c68be5f1d3b2fa036189f7864ca371c63ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/*
 *  linux/fs/proc/net.c
 *
 *  Copyright (C) 2007
 *
 *  Author: Eric Biederman <ebiederm@xmission.com>
 *
 *  proc net directory handling functions
 */

#include <asm/uaccess.h>

#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>

#include "internal.h"


struct proc_dir_entry *proc_net_fops_create(struct net *net,
	const char *name, mode_t mode, const struct file_operations *fops)
{
	struct proc_dir_entry *res;

	res = create_proc_entry(name, mode, net->proc_net);
	if (res)
		res->proc_fops = fops;
	return res;
}
EXPORT_SYMBOL_GPL(proc_net_fops_create);

void proc_net_remove(struct net *net, const char *name)
{
	remove_proc_entry(name, net->proc_net);
}
EXPORT_SYMBOL_GPL(proc_net_remove);

struct net *get_proc_net(const struct inode *inode)
{
	return maybe_get_net(PDE_NET(PDE(inode)));
}
EXPORT_SYMBOL_GPL(get_proc_net);

static struct proc_dir_entry *proc_net_shadow;

static struct dentry *proc_net_shadow_dentry(struct dentry *parent,
						struct proc_dir_entry *de)
{
	struct dentry *shadow = NULL;
	struct inode *inode;
	if (!de)
		goto out;
	de_get(de);
	inode = proc_get_inode(parent->d_inode->i_sb, de->low_ino, de);
	if (!inode)
		goto out_de_put;
	shadow = d_alloc_name(parent, de->name);
	if (!shadow)
		goto out_iput;
	shadow->d_op = parent->d_op; /* proc_dentry_operations */
	d_instantiate(shadow, inode);
out:
	return shadow;
out_iput:
	iput(inode);
out_de_put:
	de_put(de);
	goto out;
}

static void *proc_net_follow_link(struct dentry *parent, struct nameidata *nd)
{
	struct net *net = current->nsproxy->net_ns;
	struct dentry *shadow;
	shadow = proc_net_shadow_dentry(parent, net->proc_net);
	if (!shadow)
		return ERR_PTR(-ENOENT);

	dput(nd->dentry);
	/* My dentry count is 1 and that should be enough as the
	 * shadow dentry is thrown away immediately.
	 */
	nd->dentry = shadow;
	return NULL;
}

static struct dentry *proc_net_lookup(struct inode *dir, struct dentry *dentry,
				      struct nameidata *nd)
{
	struct net *net = current->nsproxy->net_ns;
	struct dentry *shadow;

	shadow = proc_net_shadow_dentry(nd->dentry, net->proc_net);
	if (!shadow)
		return ERR_PTR(-ENOENT);

	dput(nd->dentry);
	nd->dentry = shadow;

	return shadow->d_inode->i_op->lookup(shadow->d_inode, dentry, nd);
}

static int proc_net_setattr(struct dentry *dentry, struct iattr *iattr)
{
	struct net *net = current->nsproxy->net_ns;
	struct dentry *shadow;
	int ret;

	shadow = proc_net_shadow_dentry(dentry->d_parent, net->proc_net);
	if (!shadow)
		return -ENOENT;
	ret = shadow->d_inode->i_op->setattr(shadow, iattr);
	dput(shadow);
	return ret;
}

static const struct file_operations proc_net_dir_operations = {
	.read			= generic_read_dir,
};

static struct inode_operations proc_net_dir_inode_operations = {
	.follow_link	= proc_net_follow_link,
	.lookup		= proc_net_lookup,
	.setattr	= proc_net_setattr,
};

static __net_init int proc_net_ns_init(struct net *net)
{
	struct proc_dir_entry *root, *netd, *net_statd;
	int err;

	err = -ENOMEM;
	root = kzalloc(sizeof(*root), GFP_KERNEL);
	if (!root)
		goto out;

	err = -EEXIST;
	netd = proc_mkdir("net", root);
	if (!netd)
		goto free_root;

	err = -EEXIST;
	net_statd = proc_mkdir("stat", netd);
	if (!net_statd)
		goto free_net;

	root->data = net;
	netd->data = net;
	net_statd->data = net;

	net->proc_net_root = root;
	net->proc_net = netd;
	net->proc_net_stat = net_statd;
	err = 0;

out:
	return err;
free_net:
	remove_proc_entry("net", root);
free_root:
	kfree(root);
	goto out;
}

static __net_exit void proc_net_ns_exit(struct net *net)
{
	remove_proc_entry("stat", net->proc_net);
	remove_proc_entry("net", net->proc_net_root);
	kfree(net->proc_net_root);
}

static struct pernet_operations __net_initdata proc_net_ns_ops = {
	.init = proc_net_ns_init,
	.exit = proc_net_ns_exit,
};

int __init proc_net_init(void)
{
	proc_net_shadow = proc_mkdir("net", NULL);
	proc_net_shadow->proc_iops = &proc_net_dir_inode_operations;
	proc_net_shadow->proc_fops = &proc_net_dir_operations;

	return register_pernet_subsys(&proc_net_ns_ops);
}