xref: /linux/include/net/net_namespace.h (revision bab2c80e5a6c855657482eac9e97f5f3eedb509a)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Operations on the network namespace
4  */
5 #ifndef __NET_NET_NAMESPACE_H
6 #define __NET_NET_NAMESPACE_H
7 
8 #include <linux/atomic.h>
9 #include <linux/refcount.h>
10 #include <linux/workqueue.h>
11 #include <linux/list.h>
12 #include <linux/sysctl.h>
13 
14 #include <net/flow.h>
15 #include <net/netns/core.h>
16 #include <net/netns/mib.h>
17 #include <net/netns/unix.h>
18 #include <net/netns/packet.h>
19 #include <net/netns/ipv4.h>
20 #include <net/netns/ipv6.h>
21 #include <net/netns/ieee802154_6lowpan.h>
22 #include <net/netns/sctp.h>
23 #include <net/netns/dccp.h>
24 #include <net/netns/netfilter.h>
25 #include <net/netns/x_tables.h>
26 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
27 #include <net/netns/conntrack.h>
28 #endif
29 #include <net/netns/nftables.h>
30 #include <net/netns/xfrm.h>
31 #include <net/netns/mpls.h>
32 #include <net/netns/can.h>
33 #include <linux/ns_common.h>
34 #include <linux/idr.h>
35 #include <linux/skbuff.h>
36 
37 struct user_namespace;
38 struct proc_dir_entry;
39 struct net_device;
40 struct sock;
41 struct ctl_table_header;
42 struct net_generic;
43 struct uevent_sock;
44 struct netns_ipvs;
45 
46 
47 #define NETDEV_HASHBITS    8
48 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
49 
50 struct net {
51 	refcount_t		passive;	/* To decided when the network
52 						 * namespace should be freed.
53 						 */
54 	refcount_t		count;		/* To decided when the network
55 						 *  namespace should be shut down.
56 						 */
57 	spinlock_t		rules_mod_lock;
58 
59 	atomic64_t		cookie_gen;
60 
61 	struct list_head	list;		/* list of network namespaces */
62 	struct list_head	exit_list;	/* To linked to call pernet exit
63 						 * methods on dead net (
64 						 * pernet_ops_rwsem read locked),
65 						 * or to unregister pernet ops
66 						 * (pernet_ops_rwsem write locked).
67 						 */
68 	struct llist_node	cleanup_list;	/* namespaces on death row */
69 
70 	struct user_namespace   *user_ns;	/* Owning user namespace */
71 	struct ucounts		*ucounts;
72 	spinlock_t		nsid_lock;
73 	struct idr		netns_ids;
74 
75 	struct ns_common	ns;
76 
77 	struct proc_dir_entry 	*proc_net;
78 	struct proc_dir_entry 	*proc_net_stat;
79 
80 #ifdef CONFIG_SYSCTL
81 	struct ctl_table_set	sysctls;
82 #endif
83 
84 	struct sock 		*rtnl;			/* rtnetlink socket */
85 	struct sock		*genl_sock;
86 
87 	struct uevent_sock	*uevent_sock;		/* uevent socket */
88 
89 	struct list_head 	dev_base_head;
90 	struct hlist_head 	*dev_name_head;
91 	struct hlist_head	*dev_index_head;
92 	unsigned int		dev_base_seq;	/* protected by rtnl_mutex */
93 	int			ifindex;
94 	unsigned int		dev_unreg_count;
95 
96 	/* core fib_rules */
97 	struct list_head	rules_ops;
98 
99 	struct list_head	fib_notifier_ops;  /* Populated by
100 						    * register_pernet_subsys()
101 						    */
102 	struct net_device       *loopback_dev;          /* The loopback */
103 	struct netns_core	core;
104 	struct netns_mib	mib;
105 	struct netns_packet	packet;
106 	struct netns_unix	unx;
107 	struct netns_ipv4	ipv4;
108 #if IS_ENABLED(CONFIG_IPV6)
109 	struct netns_ipv6	ipv6;
110 #endif
111 #if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
112 	struct netns_ieee802154_lowpan	ieee802154_lowpan;
113 #endif
114 #if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
115 	struct netns_sctp	sctp;
116 #endif
117 #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
118 	struct netns_dccp	dccp;
119 #endif
120 #ifdef CONFIG_NETFILTER
121 	struct netns_nf		nf;
122 	struct netns_xt		xt;
123 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
124 	struct netns_ct		ct;
125 #endif
126 #if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
127 	struct netns_nftables	nft;
128 #endif
129 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
130 	struct netns_nf_frag	nf_frag;
131 	struct ctl_table_header *nf_frag_frags_hdr;
132 #endif
133 	struct sock		*nfnl;
134 	struct sock		*nfnl_stash;
135 #if IS_ENABLED(CONFIG_NETFILTER_NETLINK_ACCT)
136 	struct list_head        nfnl_acct_list;
137 #endif
138 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
139 	struct list_head	nfct_timeout_list;
140 #endif
141 #endif
142 #ifdef CONFIG_WEXT_CORE
143 	struct sk_buff_head	wext_nlevents;
144 #endif
145 	struct net_generic __rcu	*gen;
146 
147 	/* Note : following structs are cache line aligned */
148 #ifdef CONFIG_XFRM
149 	struct netns_xfrm	xfrm;
150 #endif
151 #if IS_ENABLED(CONFIG_IP_VS)
152 	struct netns_ipvs	*ipvs;
153 #endif
154 #if IS_ENABLED(CONFIG_MPLS)
155 	struct netns_mpls	mpls;
156 #endif
157 #if IS_ENABLED(CONFIG_CAN)
158 	struct netns_can	can;
159 #endif
160 	struct sock		*diag_nlsk;
161 	atomic_t		fnhe_genid;
162 } __randomize_layout;
163 
164 #include <linux/seq_file_net.h>
165 
166 /* Init's network namespace */
167 extern struct net init_net;
168 
169 #ifdef CONFIG_NET_NS
170 struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
171 			struct net *old_net);
172 
173 void net_ns_barrier(void);
174 #else /* CONFIG_NET_NS */
175 #include <linux/sched.h>
176 #include <linux/nsproxy.h>
177 static inline struct net *copy_net_ns(unsigned long flags,
178 	struct user_namespace *user_ns, struct net *old_net)
179 {
180 	if (flags & CLONE_NEWNET)
181 		return ERR_PTR(-EINVAL);
182 	return old_net;
183 }
184 
185 static inline void net_ns_barrier(void) {}
186 #endif /* CONFIG_NET_NS */
187 
188 
189 extern struct list_head net_namespace_list;
190 
191 struct net *get_net_ns_by_pid(pid_t pid);
192 struct net *get_net_ns_by_fd(int fd);
193 
194 #ifdef CONFIG_SYSCTL
195 void ipx_register_sysctl(void);
196 void ipx_unregister_sysctl(void);
197 #else
198 #define ipx_register_sysctl()
199 #define ipx_unregister_sysctl()
200 #endif
201 
202 #ifdef CONFIG_NET_NS
203 void __put_net(struct net *net);
204 
205 static inline struct net *get_net(struct net *net)
206 {
207 	refcount_inc(&net->count);
208 	return net;
209 }
210 
211 static inline struct net *maybe_get_net(struct net *net)
212 {
213 	/* Used when we know struct net exists but we
214 	 * aren't guaranteed a previous reference count
215 	 * exists.  If the reference count is zero this
216 	 * function fails and returns NULL.
217 	 */
218 	if (!refcount_inc_not_zero(&net->count))
219 		net = NULL;
220 	return net;
221 }
222 
223 static inline void put_net(struct net *net)
224 {
225 	if (refcount_dec_and_test(&net->count))
226 		__put_net(net);
227 }
228 
229 static inline
230 int net_eq(const struct net *net1, const struct net *net2)
231 {
232 	return net1 == net2;
233 }
234 
235 static inline int check_net(const struct net *net)
236 {
237 	return refcount_read(&net->count) != 0;
238 }
239 
240 void net_drop_ns(void *);
241 
242 #else
243 
244 static inline struct net *get_net(struct net *net)
245 {
246 	return net;
247 }
248 
249 static inline void put_net(struct net *net)
250 {
251 }
252 
253 static inline struct net *maybe_get_net(struct net *net)
254 {
255 	return net;
256 }
257 
258 static inline
259 int net_eq(const struct net *net1, const struct net *net2)
260 {
261 	return 1;
262 }
263 
264 static inline int check_net(const struct net *net)
265 {
266 	return 1;
267 }
268 
269 #define net_drop_ns NULL
270 #endif
271 
272 
273 typedef struct {
274 #ifdef CONFIG_NET_NS
275 	struct net *net;
276 #endif
277 } possible_net_t;
278 
279 static inline void write_pnet(possible_net_t *pnet, struct net *net)
280 {
281 #ifdef CONFIG_NET_NS
282 	pnet->net = net;
283 #endif
284 }
285 
286 static inline struct net *read_pnet(const possible_net_t *pnet)
287 {
288 #ifdef CONFIG_NET_NS
289 	return pnet->net;
290 #else
291 	return &init_net;
292 #endif
293 }
294 
295 /* Protected by net_rwsem */
296 #define for_each_net(VAR)				\
297 	list_for_each_entry(VAR, &net_namespace_list, list)
298 
299 #define for_each_net_rcu(VAR)				\
300 	list_for_each_entry_rcu(VAR, &net_namespace_list, list)
301 
302 #ifdef CONFIG_NET_NS
303 #define __net_init
304 #define __net_exit
305 #define __net_initdata
306 #define __net_initconst
307 #else
308 #define __net_init	__init
309 #define __net_exit	__ref
310 #define __net_initdata	__initdata
311 #define __net_initconst	__initconst
312 #endif
313 
314 int peernet2id_alloc(struct net *net, struct net *peer);
315 int peernet2id(struct net *net, struct net *peer);
316 bool peernet_has_id(struct net *net, struct net *peer);
317 struct net *get_net_ns_by_id(struct net *net, int id);
318 
319 struct pernet_operations {
320 	struct list_head list;
321 	/*
322 	 * Below methods are called without any exclusive locks.
323 	 * More than one net may be constructed and destructed
324 	 * in parallel on several cpus. Every pernet_operations
325 	 * have to keep in mind all other pernet_operations and
326 	 * to introduce a locking, if they share common resources.
327 	 *
328 	 * The only time they are called with exclusive lock is
329 	 * from register_pernet_subsys(), unregister_pernet_subsys()
330 	 * register_pernet_device() and unregister_pernet_device().
331 	 *
332 	 * Exit methods using blocking RCU primitives, such as
333 	 * synchronize_rcu(), should be implemented via exit_batch.
334 	 * Then, destruction of a group of net requires single
335 	 * synchronize_rcu() related to these pernet_operations,
336 	 * instead of separate synchronize_rcu() for every net.
337 	 * Please, avoid synchronize_rcu() at all, where it's possible.
338 	 */
339 	int (*init)(struct net *net);
340 	void (*exit)(struct net *net);
341 	void (*exit_batch)(struct list_head *net_exit_list);
342 	unsigned int *id;
343 	size_t size;
344 };
345 
346 /*
347  * Use these carefully.  If you implement a network device and it
348  * needs per network namespace operations use device pernet operations,
349  * otherwise use pernet subsys operations.
350  *
351  * Network interfaces need to be removed from a dying netns _before_
352  * subsys notifiers can be called, as most of the network code cleanup
353  * (which is done from subsys notifiers) runs with the assumption that
354  * dev_remove_pack has been called so no new packets will arrive during
355  * and after the cleanup functions have been called.  dev_remove_pack
356  * is not per namespace so instead the guarantee of no more packets
357  * arriving in a network namespace is provided by ensuring that all
358  * network devices and all sockets have left the network namespace
359  * before the cleanup methods are called.
360  *
361  * For the longest time the ipv4 icmp code was registered as a pernet
362  * device which caused kernel oops, and panics during network
363  * namespace cleanup.   So please don't get this wrong.
364  */
365 int register_pernet_subsys(struct pernet_operations *);
366 void unregister_pernet_subsys(struct pernet_operations *);
367 int register_pernet_device(struct pernet_operations *);
368 void unregister_pernet_device(struct pernet_operations *);
369 
370 struct ctl_table;
371 struct ctl_table_header;
372 
373 #ifdef CONFIG_SYSCTL
374 int net_sysctl_init(void);
375 struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
376 					     struct ctl_table *table);
377 void unregister_net_sysctl_table(struct ctl_table_header *header);
378 #else
379 static inline int net_sysctl_init(void) { return 0; }
380 static inline struct ctl_table_header *register_net_sysctl(struct net *net,
381 	const char *path, struct ctl_table *table)
382 {
383 	return NULL;
384 }
385 static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
386 {
387 }
388 #endif
389 
390 static inline int rt_genid_ipv4(struct net *net)
391 {
392 	return atomic_read(&net->ipv4.rt_genid);
393 }
394 
395 static inline void rt_genid_bump_ipv4(struct net *net)
396 {
397 	atomic_inc(&net->ipv4.rt_genid);
398 }
399 
400 extern void (*__fib6_flush_trees)(struct net *net);
401 static inline void rt_genid_bump_ipv6(struct net *net)
402 {
403 	if (__fib6_flush_trees)
404 		__fib6_flush_trees(net);
405 }
406 
407 #if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
408 static inline struct netns_ieee802154_lowpan *
409 net_ieee802154_lowpan(struct net *net)
410 {
411 	return &net->ieee802154_lowpan;
412 }
413 #endif
414 
415 /* For callers who don't really care about whether it's IPv4 or IPv6 */
416 static inline void rt_genid_bump_all(struct net *net)
417 {
418 	rt_genid_bump_ipv4(net);
419 	rt_genid_bump_ipv6(net);
420 }
421 
422 static inline int fnhe_genid(struct net *net)
423 {
424 	return atomic_read(&net->fnhe_genid);
425 }
426 
427 static inline void fnhe_genid_bump(struct net *net)
428 {
429 	atomic_inc(&net->fnhe_genid);
430 }
431 
432 #endif /* __NET_NET_NAMESPACE_H */
433