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-rw-r--r--include/net/net_namespace.h68
-rw-r--r--net/core/Makefile2
-rw-r--r--net/core/net_namespace.c292
3 files changed, 361 insertions, 1 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
new file mode 100644
index 000000000000..6344b77f81a2
--- /dev/null
+++ b/include/net/net_namespace.h
@@ -0,0 +1,68 @@
1/*
2 * Operations on the network namespace
3 */
4#ifndef __NET_NET_NAMESPACE_H
5#define __NET_NET_NAMESPACE_H
6
7#include <asm/atomic.h>
8#include <linux/workqueue.h>
9#include <linux/list.h>
10
11struct net {
12 atomic_t count; /* To decided when the network
13 * namespace should be freed.
14 */
15 atomic_t use_count; /* To track references we
16 * destroy on demand
17 */
18 struct list_head list; /* list of network namespaces */
19 struct work_struct work; /* work struct for freeing */
20};
21
22extern struct net init_net;
23extern struct list_head net_namespace_list;
24
25extern void __put_net(struct net *net);
26
27static inline struct net *get_net(struct net *net)
28{
29 atomic_inc(&net->count);
30 return net;
31}
32
33static inline void put_net(struct net *net)
34{
35 if (atomic_dec_and_test(&net->count))
36 __put_net(net);
37}
38
39static inline struct net *hold_net(struct net *net)
40{
41 atomic_inc(&net->use_count);
42 return net;
43}
44
45static inline void release_net(struct net *net)
46{
47 atomic_dec(&net->use_count);
48}
49
50extern void net_lock(void);
51extern void net_unlock(void);
52
53#define for_each_net(VAR) \
54 list_for_each_entry(VAR, &net_namespace_list, list)
55
56
57struct pernet_operations {
58 struct list_head list;
59 int (*init)(struct net *net);
60 void (*exit)(struct net *net);
61};
62
63extern int register_pernet_subsys(struct pernet_operations *);
64extern void unregister_pernet_subsys(struct pernet_operations *);
65extern int register_pernet_device(struct pernet_operations *);
66extern void unregister_pernet_device(struct pernet_operations *);
67
68#endif /* __NET_NET_NAMESPACE_H */
diff --git a/net/core/Makefile b/net/core/Makefile
index 4751613e1b59..ea9b3f32d1c0 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -3,7 +3,7 @@
3# 3#
4 4
5obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \ 5obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
6 gen_stats.o gen_estimator.o 6 gen_stats.o gen_estimator.o net_namespace.o
7 7
8obj-$(CONFIG_SYSCTL) += sysctl_net_core.o 8obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
9 9
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
new file mode 100644
index 000000000000..f259a9b6fdc1
--- /dev/null
+++ b/net/core/net_namespace.c
@@ -0,0 +1,292 @@
1#include <linux/workqueue.h>
2#include <linux/rtnetlink.h>
3#include <linux/cache.h>
4#include <linux/slab.h>
5#include <linux/list.h>
6#include <linux/delay.h>
7#include <net/net_namespace.h>
8
9/*
10 * Our network namespace constructor/destructor lists
11 */
12
13static LIST_HEAD(pernet_list);
14static struct list_head *first_device = &pernet_list;
15static DEFINE_MUTEX(net_mutex);
16
17static DEFINE_MUTEX(net_list_mutex);
18LIST_HEAD(net_namespace_list);
19
20static struct kmem_cache *net_cachep;
21
22struct net init_net;
23EXPORT_SYMBOL_GPL(init_net);
24
25void net_lock(void)
26{
27 mutex_lock(&net_list_mutex);
28}
29
30void net_unlock(void)
31{
32 mutex_unlock(&net_list_mutex);
33}
34
35static struct net *net_alloc(void)
36{
37 return kmem_cache_alloc(net_cachep, GFP_KERNEL);
38}
39
40static void net_free(struct net *net)
41{
42 if (!net)
43 return;
44
45 if (unlikely(atomic_read(&net->use_count) != 0)) {
46 printk(KERN_EMERG "network namespace not free! Usage: %d\n",
47 atomic_read(&net->use_count));
48 return;
49 }
50
51 kmem_cache_free(net_cachep, net);
52}
53
54static void cleanup_net(struct work_struct *work)
55{
56 struct pernet_operations *ops;
57 struct list_head *ptr;
58 struct net *net;
59
60 net = container_of(work, struct net, work);
61
62 mutex_lock(&net_mutex);
63
64 /* Don't let anyone else find us. */
65 net_lock();
66 list_del(&net->list);
67 net_unlock();
68
69 /* Run all of the network namespace exit methods */
70 list_for_each_prev(ptr, &pernet_list) {
71 ops = list_entry(ptr, struct pernet_operations, list);
72 if (ops->exit)
73 ops->exit(net);
74 }
75
76 mutex_unlock(&net_mutex);
77
78 /* Ensure there are no outstanding rcu callbacks using this
79 * network namespace.
80 */
81 rcu_barrier();
82
83 /* Finally it is safe to free my network namespace structure */
84 net_free(net);
85}
86
87
88void __put_net(struct net *net)
89{
90 /* Cleanup the network namespace in process context */
91 INIT_WORK(&net->work, cleanup_net);
92 schedule_work(&net->work);
93}
94EXPORT_SYMBOL_GPL(__put_net);
95
96/*
97 * setup_net runs the initializers for the network namespace object.
98 */
99static int setup_net(struct net *net)
100{
101 /* Must be called with net_mutex held */
102 struct pernet_operations *ops;
103 struct list_head *ptr;
104 int error;
105
106 memset(net, 0, sizeof(struct net));
107 atomic_set(&net->count, 1);
108 atomic_set(&net->use_count, 0);
109
110 error = 0;
111 list_for_each(ptr, &pernet_list) {
112 ops = list_entry(ptr, struct pernet_operations, list);
113 if (ops->init) {
114 error = ops->init(net);
115 if (error < 0)
116 goto out_undo;
117 }
118 }
119out:
120 return error;
121out_undo:
122 /* Walk through the list backwards calling the exit functions
123 * for the pernet modules whose init functions did not fail.
124 */
125 for (ptr = ptr->prev; ptr != &pernet_list; ptr = ptr->prev) {
126 ops = list_entry(ptr, struct pernet_operations, list);
127 if (ops->exit)
128 ops->exit(net);
129 }
130 goto out;
131}
132
133static int __init net_ns_init(void)
134{
135 int err;
136
137 printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net));
138 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
139 SMP_CACHE_BYTES,
140 SLAB_PANIC, NULL);
141 mutex_lock(&net_mutex);
142 err = setup_net(&init_net);
143
144 net_lock();
145 list_add_tail(&init_net.list, &net_namespace_list);
146 net_unlock();
147
148 mutex_unlock(&net_mutex);
149 if (err)
150 panic("Could not setup the initial network namespace");
151
152 return 0;
153}
154
155pure_initcall(net_ns_init);
156
157static int register_pernet_operations(struct list_head *list,
158 struct pernet_operations *ops)
159{
160 struct net *net, *undo_net;
161 int error;
162
163 error = 0;
164 list_add_tail(&ops->list, list);
165 for_each_net(net) {
166 if (ops->init) {
167 error = ops->init(net);
168 if (error)
169 goto out_undo;
170 }
171 }
172out:
173 return error;
174
175out_undo:
176 /* If I have an error cleanup all namespaces I initialized */
177 list_del(&ops->list);
178 for_each_net(undo_net) {
179 if (undo_net == net)
180 goto undone;
181 if (ops->exit)
182 ops->exit(undo_net);
183 }
184undone:
185 goto out;
186}
187
188static void unregister_pernet_operations(struct pernet_operations *ops)
189{
190 struct net *net;
191
192 list_del(&ops->list);
193 for_each_net(net)
194 if (ops->exit)
195 ops->exit(net);
196}
197
198/**
199 * register_pernet_subsys - register a network namespace subsystem
200 * @ops: pernet operations structure for the subsystem
201 *
202 * Register a subsystem which has init and exit functions
203 * that are called when network namespaces are created and
204 * destroyed respectively.
205 *
206 * When registered all network namespace init functions are
207 * called for every existing network namespace. Allowing kernel
208 * modules to have a race free view of the set of network namespaces.
209 *
210 * When a new network namespace is created all of the init
211 * methods are called in the order in which they were registered.
212 *
213 * When a network namespace is destroyed all of the exit methods
214 * are called in the reverse of the order with which they were
215 * registered.
216 */
217int register_pernet_subsys(struct pernet_operations *ops)
218{
219 int error;
220 mutex_lock(&net_mutex);
221 error = register_pernet_operations(first_device, ops);
222 mutex_unlock(&net_mutex);
223 return error;
224}
225EXPORT_SYMBOL_GPL(register_pernet_subsys);
226
227/**
228 * unregister_pernet_subsys - unregister a network namespace subsystem
229 * @ops: pernet operations structure to manipulate
230 *
231 * Remove the pernet operations structure from the list to be
232 * used when network namespaces are created or destoryed. In
233 * addition run the exit method for all existing network
234 * namespaces.
235 */
236void unregister_pernet_subsys(struct pernet_operations *module)
237{
238 mutex_lock(&net_mutex);
239 unregister_pernet_operations(module);
240 mutex_unlock(&net_mutex);
241}
242EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
243
244/**
245 * register_pernet_device - register a network namespace device
246 * @ops: pernet operations structure for the subsystem
247 *
248 * Register a device which has init and exit functions
249 * that are called when network namespaces are created and
250 * destroyed respectively.
251 *
252 * When registered all network namespace init functions are
253 * called for every existing network namespace. Allowing kernel
254 * modules to have a race free view of the set of network namespaces.
255 *
256 * When a new network namespace is created all of the init
257 * methods are called in the order in which they were registered.
258 *
259 * When a network namespace is destroyed all of the exit methods
260 * are called in the reverse of the order with which they were
261 * registered.
262 */
263int register_pernet_device(struct pernet_operations *ops)
264{
265 int error;
266 mutex_lock(&net_mutex);
267 error = register_pernet_operations(&pernet_list, ops);
268 if (!error && (first_device == &pernet_list))
269 first_device = &ops->list;
270 mutex_unlock(&net_mutex);
271 return error;
272}
273EXPORT_SYMBOL_GPL(register_pernet_device);
274
275/**
276 * unregister_pernet_device - unregister a network namespace netdevice
277 * @ops: pernet operations structure to manipulate
278 *
279 * Remove the pernet operations structure from the list to be
280 * used when network namespaces are created or destoryed. In
281 * addition run the exit method for all existing network
282 * namespaces.
283 */
284void unregister_pernet_device(struct pernet_operations *ops)
285{
286 mutex_lock(&net_mutex);
287 if (&ops->list == first_device)
288 first_device = first_device->next;
289 unregister_pernet_operations(ops);
290 mutex_unlock(&net_mutex);
291}
292EXPORT_SYMBOL_GPL(unregister_pernet_device);
generated by cgit v1.2.2 (git 2.25.0) at 2026-01-08 02:47:15 -0500