xref: /linux/include/net/net_namespace.h (revision 768e4bb6)
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 #include <linux/uidgid.h>
14 
15 #include <net/flow.h>
16 #include <net/netns/core.h>
17 #include <net/netns/mib.h>
18 #include <net/netns/unix.h>
19 #include <net/netns/packet.h>
20 #include <net/netns/ipv4.h>
21 #include <net/netns/ipv6.h>
22 #include <net/netns/nexthop.h>
23 #include <net/netns/ieee802154_6lowpan.h>
24 #include <net/netns/sctp.h>
25 #include <net/netns/netfilter.h>
26 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
27 #include <net/netns/conntrack.h>
28 #endif
29 #if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
30 #include <net/netns/flow_table.h>
31 #endif
32 #include <net/netns/nftables.h>
33 #include <net/netns/xfrm.h>
34 #include <net/netns/mpls.h>
35 #include <net/netns/can.h>
36 #include <net/netns/xdp.h>
37 #include <net/netns/smc.h>
38 #include <net/netns/bpf.h>
39 #include <net/netns/mctp.h>
40 #include <net/net_trackers.h>
41 #include <linux/ns_common.h>
42 #include <linux/idr.h>
43 #include <linux/skbuff.h>
44 #include <linux/notifier.h>
45 #include <linux/xarray.h>
46 
47 struct user_namespace;
48 struct proc_dir_entry;
49 struct net_device;
50 struct sock;
51 struct ctl_table_header;
52 struct net_generic;
53 struct uevent_sock;
54 struct netns_ipvs;
55 struct bpf_prog;
56 
57 
58 #define NETDEV_HASHBITS    8
59 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
60 
61 struct net {
62 	/* First cache line can be often dirtied.
63 	 * Do not place here read-mostly fields.
64 	 */
65 	refcount_t		passive;	/* To decide when the network
66 						 * namespace should be freed.
67 						 */
68 	spinlock_t		rules_mod_lock;
69 
70 	unsigned int		dev_base_seq;	/* protected by rtnl_mutex */
71 	u32			ifindex;
72 
73 	spinlock_t		nsid_lock;
74 	atomic_t		fnhe_genid;
75 
76 	struct list_head	list;		/* list of network namespaces */
77 	struct list_head	exit_list;	/* To linked to call pernet exit
78 						 * methods on dead net (
79 						 * pernet_ops_rwsem read locked),
80 						 * or to unregister pernet ops
81 						 * (pernet_ops_rwsem write locked).
82 						 */
83 	struct llist_node	cleanup_list;	/* namespaces on death row */
84 
85 #ifdef CONFIG_KEYS
86 	struct key_tag		*key_domain;	/* Key domain of operation tag */
87 #endif
88 	struct user_namespace   *user_ns;	/* Owning user namespace */
89 	struct ucounts		*ucounts;
90 	struct idr		netns_ids;
91 
92 	struct ns_common	ns;
93 	struct ref_tracker_dir  refcnt_tracker;
94 	struct ref_tracker_dir  notrefcnt_tracker; /* tracker for objects not
95 						    * refcounted against netns
96 						    */
97 	struct list_head 	dev_base_head;
98 	struct proc_dir_entry 	*proc_net;
99 	struct proc_dir_entry 	*proc_net_stat;
100 
101 #ifdef CONFIG_SYSCTL
102 	struct ctl_table_set	sysctls;
103 #endif
104 
105 	struct sock 		*rtnl;			/* rtnetlink socket */
106 	struct sock		*genl_sock;
107 
108 	struct uevent_sock	*uevent_sock;		/* uevent socket */
109 
110 	struct hlist_head 	*dev_name_head;
111 	struct hlist_head	*dev_index_head;
112 	struct xarray		dev_by_index;
113 	struct raw_notifier_head	netdev_chain;
114 
115 	/* Note that @hash_mix can be read millions times per second,
116 	 * it is critical that it is on a read_mostly cache line.
117 	 */
118 	u32			hash_mix;
119 
120 	struct net_device       *loopback_dev;          /* The loopback */
121 
122 	/* core fib_rules */
123 	struct list_head	rules_ops;
124 
125 	struct netns_core	core;
126 	struct netns_mib	mib;
127 	struct netns_packet	packet;
128 #if IS_ENABLED(CONFIG_UNIX)
129 	struct netns_unix	unx;
130 #endif
131 	struct netns_nexthop	nexthop;
132 	struct netns_ipv4	ipv4;
133 #if IS_ENABLED(CONFIG_IPV6)
134 	struct netns_ipv6	ipv6;
135 #endif
136 #if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
137 	struct netns_ieee802154_lowpan	ieee802154_lowpan;
138 #endif
139 #if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
140 	struct netns_sctp	sctp;
141 #endif
142 #ifdef CONFIG_NETFILTER
143 	struct netns_nf		nf;
144 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
145 	struct netns_ct		ct;
146 #endif
147 #if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
148 	struct netns_nftables	nft;
149 #endif
150 #if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
151 	struct netns_ft ft;
152 #endif
153 #endif
154 #ifdef CONFIG_WEXT_CORE
155 	struct sk_buff_head	wext_nlevents;
156 #endif
157 	struct net_generic __rcu	*gen;
158 
159 	/* Used to store attached BPF programs */
160 	struct netns_bpf	bpf;
161 
162 	/* Note : following structs are cache line aligned */
163 #ifdef CONFIG_XFRM
164 	struct netns_xfrm	xfrm;
165 #endif
166 
167 	u64			net_cookie; /* written once */
168 
169 #if IS_ENABLED(CONFIG_IP_VS)
170 	struct netns_ipvs	*ipvs;
171 #endif
172 #if IS_ENABLED(CONFIG_MPLS)
173 	struct netns_mpls	mpls;
174 #endif
175 #if IS_ENABLED(CONFIG_CAN)
176 	struct netns_can	can;
177 #endif
178 #ifdef CONFIG_XDP_SOCKETS
179 	struct netns_xdp	xdp;
180 #endif
181 #if IS_ENABLED(CONFIG_MCTP)
182 	struct netns_mctp	mctp;
183 #endif
184 #if IS_ENABLED(CONFIG_CRYPTO_USER)
185 	struct sock		*crypto_nlsk;
186 #endif
187 	struct sock		*diag_nlsk;
188 #if IS_ENABLED(CONFIG_SMC)
189 	struct netns_smc	smc;
190 #endif
191 } __randomize_layout;
192 
193 #include <linux/seq_file_net.h>
194 
195 /* Init's network namespace */
196 extern struct net init_net;
197 
198 #ifdef CONFIG_NET_NS
199 struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
200 			struct net *old_net);
201 
202 void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
203 
204 void net_ns_barrier(void);
205 
206 struct ns_common *get_net_ns(struct ns_common *ns);
207 struct net *get_net_ns_by_fd(int fd);
208 #else /* CONFIG_NET_NS */
209 #include <linux/sched.h>
210 #include <linux/nsproxy.h>
copy_net_ns(unsigned long flags,struct user_namespace * user_ns,struct net * old_net)211 static inline struct net *copy_net_ns(unsigned long flags,
212 	struct user_namespace *user_ns, struct net *old_net)
213 {
214 	if (flags & CLONE_NEWNET)
215 		return ERR_PTR(-EINVAL);
216 	return old_net;
217 }
218 
net_ns_get_ownership(const struct net * net,kuid_t * uid,kgid_t * gid)219 static inline void net_ns_get_ownership(const struct net *net,
220 					kuid_t *uid, kgid_t *gid)
221 {
222 	*uid = GLOBAL_ROOT_UID;
223 	*gid = GLOBAL_ROOT_GID;
224 }
225 
net_ns_barrier(void)226 static inline void net_ns_barrier(void) {}
227 
get_net_ns(struct ns_common * ns)228 static inline struct ns_common *get_net_ns(struct ns_common *ns)
229 {
230 	return ERR_PTR(-EINVAL);
231 }
232 
get_net_ns_by_fd(int fd)233 static inline struct net *get_net_ns_by_fd(int fd)
234 {
235 	return ERR_PTR(-EINVAL);
236 }
237 #endif /* CONFIG_NET_NS */
238 
239 
240 extern struct list_head net_namespace_list;
241 
242 struct net *get_net_ns_by_pid(pid_t pid);
243 
244 #ifdef CONFIG_SYSCTL
245 void ipx_register_sysctl(void);
246 void ipx_unregister_sysctl(void);
247 #else
248 #define ipx_register_sysctl()
249 #define ipx_unregister_sysctl()
250 #endif
251 
252 #ifdef CONFIG_NET_NS
253 void __put_net(struct net *net);
254 
255 /* Try using get_net_track() instead */
get_net(struct net * net)256 static inline struct net *get_net(struct net *net)
257 {
258 	refcount_inc(&net->ns.count);
259 	return net;
260 }
261 
maybe_get_net(struct net * net)262 static inline struct net *maybe_get_net(struct net *net)
263 {
264 	/* Used when we know struct net exists but we
265 	 * aren't guaranteed a previous reference count
266 	 * exists.  If the reference count is zero this
267 	 * function fails and returns NULL.
268 	 */
269 	if (!refcount_inc_not_zero(&net->ns.count))
270 		net = NULL;
271 	return net;
272 }
273 
274 /* Try using put_net_track() instead */
put_net(struct net * net)275 static inline void put_net(struct net *net)
276 {
277 	if (refcount_dec_and_test(&net->ns.count))
278 		__put_net(net);
279 }
280 
281 static inline
net_eq(const struct net * net1,const struct net * net2)282 int net_eq(const struct net *net1, const struct net *net2)
283 {
284 	return net1 == net2;
285 }
286 
check_net(const struct net * net)287 static inline int check_net(const struct net *net)
288 {
289 	return refcount_read(&net->ns.count) != 0;
290 }
291 
292 void net_drop_ns(void *);
293 
294 #else
295 
get_net(struct net * net)296 static inline struct net *get_net(struct net *net)
297 {
298 	return net;
299 }
300 
put_net(struct net * net)301 static inline void put_net(struct net *net)
302 {
303 }
304 
maybe_get_net(struct net * net)305 static inline struct net *maybe_get_net(struct net *net)
306 {
307 	return net;
308 }
309 
310 static inline
net_eq(const struct net * net1,const struct net * net2)311 int net_eq(const struct net *net1, const struct net *net2)
312 {
313 	return 1;
314 }
315 
check_net(const struct net * net)316 static inline int check_net(const struct net *net)
317 {
318 	return 1;
319 }
320 
321 #define net_drop_ns NULL
322 #endif
323 
324 
__netns_tracker_alloc(struct net * net,netns_tracker * tracker,bool refcounted,gfp_t gfp)325 static inline void __netns_tracker_alloc(struct net *net,
326 					 netns_tracker *tracker,
327 					 bool refcounted,
328 					 gfp_t gfp)
329 {
330 #ifdef CONFIG_NET_NS_REFCNT_TRACKER
331 	ref_tracker_alloc(refcounted ? &net->refcnt_tracker :
332 				       &net->notrefcnt_tracker,
333 			  tracker, gfp);
334 #endif
335 }
336 
netns_tracker_alloc(struct net * net,netns_tracker * tracker,gfp_t gfp)337 static inline void netns_tracker_alloc(struct net *net, netns_tracker *tracker,
338 				       gfp_t gfp)
339 {
340 	__netns_tracker_alloc(net, tracker, true, gfp);
341 }
342 
__netns_tracker_free(struct net * net,netns_tracker * tracker,bool refcounted)343 static inline void __netns_tracker_free(struct net *net,
344 					netns_tracker *tracker,
345 					bool refcounted)
346 {
347 #ifdef CONFIG_NET_NS_REFCNT_TRACKER
348        ref_tracker_free(refcounted ? &net->refcnt_tracker :
349 				     &net->notrefcnt_tracker, tracker);
350 #endif
351 }
352 
get_net_track(struct net * net,netns_tracker * tracker,gfp_t gfp)353 static inline struct net *get_net_track(struct net *net,
354 					netns_tracker *tracker, gfp_t gfp)
355 {
356 	get_net(net);
357 	netns_tracker_alloc(net, tracker, gfp);
358 	return net;
359 }
360 
put_net_track(struct net * net,netns_tracker * tracker)361 static inline void put_net_track(struct net *net, netns_tracker *tracker)
362 {
363 	__netns_tracker_free(net, tracker, true);
364 	put_net(net);
365 }
366 
367 typedef struct {
368 #ifdef CONFIG_NET_NS
369 	struct net __rcu *net;
370 #endif
371 } possible_net_t;
372 
write_pnet(possible_net_t * pnet,struct net * net)373 static inline void write_pnet(possible_net_t *pnet, struct net *net)
374 {
375 #ifdef CONFIG_NET_NS
376 	rcu_assign_pointer(pnet->net, net);
377 #endif
378 }
379 
read_pnet(const possible_net_t * pnet)380 static inline struct net *read_pnet(const possible_net_t *pnet)
381 {
382 #ifdef CONFIG_NET_NS
383 	return rcu_dereference_protected(pnet->net, true);
384 #else
385 	return &init_net;
386 #endif
387 }
388 
read_pnet_rcu(possible_net_t * pnet)389 static inline struct net *read_pnet_rcu(possible_net_t *pnet)
390 {
391 #ifdef CONFIG_NET_NS
392 	return rcu_dereference(pnet->net);
393 #else
394 	return &init_net;
395 #endif
396 }
397 
398 /* Protected by net_rwsem */
399 #define for_each_net(VAR)				\
400 	list_for_each_entry(VAR, &net_namespace_list, list)
401 #define for_each_net_continue_reverse(VAR)		\
402 	list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
403 #define for_each_net_rcu(VAR)				\
404 	list_for_each_entry_rcu(VAR, &net_namespace_list, list)
405 
406 #ifdef CONFIG_NET_NS
407 #define __net_init
408 #define __net_exit
409 #define __net_initdata
410 #define __net_initconst
411 #else
412 #define __net_init	__init
413 #define __net_exit	__ref
414 #define __net_initdata	__initdata
415 #define __net_initconst	__initconst
416 #endif
417 
418 int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp);
419 int peernet2id(const struct net *net, struct net *peer);
420 bool peernet_has_id(const struct net *net, struct net *peer);
421 struct net *get_net_ns_by_id(const struct net *net, int id);
422 
423 struct pernet_operations {
424 	struct list_head list;
425 	/*
426 	 * Below methods are called without any exclusive locks.
427 	 * More than one net may be constructed and destructed
428 	 * in parallel on several cpus. Every pernet_operations
429 	 * have to keep in mind all other pernet_operations and
430 	 * to introduce a locking, if they share common resources.
431 	 *
432 	 * The only time they are called with exclusive lock is
433 	 * from register_pernet_subsys(), unregister_pernet_subsys()
434 	 * register_pernet_device() and unregister_pernet_device().
435 	 *
436 	 * Exit methods using blocking RCU primitives, such as
437 	 * synchronize_rcu(), should be implemented via exit_batch.
438 	 * Then, destruction of a group of net requires single
439 	 * synchronize_rcu() related to these pernet_operations,
440 	 * instead of separate synchronize_rcu() for every net.
441 	 * Please, avoid synchronize_rcu() at all, where it's possible.
442 	 *
443 	 * Note that a combination of pre_exit() and exit() can
444 	 * be used, since a synchronize_rcu() is guaranteed between
445 	 * the calls.
446 	 */
447 	int (*init)(struct net *net);
448 	void (*pre_exit)(struct net *net);
449 	void (*exit)(struct net *net);
450 	void (*exit_batch)(struct list_head *net_exit_list);
451 	/* Following method is called with RTNL held. */
452 	void (*exit_batch_rtnl)(struct list_head *net_exit_list,
453 				struct list_head *dev_kill_list);
454 	unsigned int * const id;
455 	const size_t size;
456 };
457 
458 /*
459  * Use these carefully.  If you implement a network device and it
460  * needs per network namespace operations use device pernet operations,
461  * otherwise use pernet subsys operations.
462  *
463  * Network interfaces need to be removed from a dying netns _before_
464  * subsys notifiers can be called, as most of the network code cleanup
465  * (which is done from subsys notifiers) runs with the assumption that
466  * dev_remove_pack has been called so no new packets will arrive during
467  * and after the cleanup functions have been called.  dev_remove_pack
468  * is not per namespace so instead the guarantee of no more packets
469  * arriving in a network namespace is provided by ensuring that all
470  * network devices and all sockets have left the network namespace
471  * before the cleanup methods are called.
472  *
473  * For the longest time the ipv4 icmp code was registered as a pernet
474  * device which caused kernel oops, and panics during network
475  * namespace cleanup.   So please don't get this wrong.
476  */
477 int register_pernet_subsys(struct pernet_operations *);
478 void unregister_pernet_subsys(struct pernet_operations *);
479 int register_pernet_device(struct pernet_operations *);
480 void unregister_pernet_device(struct pernet_operations *);
481 
482 struct ctl_table;
483 
484 #define register_net_sysctl(net, path, table)	\
485 	register_net_sysctl_sz(net, path, table, ARRAY_SIZE(table))
486 #ifdef CONFIG_SYSCTL
487 int net_sysctl_init(void);
488 struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,
489 					     struct ctl_table *table, size_t table_size);
490 void unregister_net_sysctl_table(struct ctl_table_header *header);
491 #else
net_sysctl_init(void)492 static inline int net_sysctl_init(void) { return 0; }
register_net_sysctl_sz(struct net * net,const char * path,struct ctl_table * table,size_t table_size)493 static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,
494 	const char *path, struct ctl_table *table, size_t table_size)
495 {
496 	return NULL;
497 }
unregister_net_sysctl_table(struct ctl_table_header * header)498 static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
499 {
500 }
501 #endif
502 
rt_genid_ipv4(const struct net * net)503 static inline int rt_genid_ipv4(const struct net *net)
504 {
505 	return atomic_read(&net->ipv4.rt_genid);
506 }
507 
508 #if IS_ENABLED(CONFIG_IPV6)
rt_genid_ipv6(const struct net * net)509 static inline int rt_genid_ipv6(const struct net *net)
510 {
511 	return atomic_read(&net->ipv6.fib6_sernum);
512 }
513 #endif
514 
rt_genid_bump_ipv4(struct net * net)515 static inline void rt_genid_bump_ipv4(struct net *net)
516 {
517 	atomic_inc(&net->ipv4.rt_genid);
518 }
519 
520 extern void (*__fib6_flush_trees)(struct net *net);
rt_genid_bump_ipv6(struct net * net)521 static inline void rt_genid_bump_ipv6(struct net *net)
522 {
523 	if (__fib6_flush_trees)
524 		__fib6_flush_trees(net);
525 }
526 
527 #if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
528 static inline struct netns_ieee802154_lowpan *
net_ieee802154_lowpan(struct net * net)529 net_ieee802154_lowpan(struct net *net)
530 {
531 	return &net->ieee802154_lowpan;
532 }
533 #endif
534 
535 /* For callers who don't really care about whether it's IPv4 or IPv6 */
rt_genid_bump_all(struct net * net)536 static inline void rt_genid_bump_all(struct net *net)
537 {
538 	rt_genid_bump_ipv4(net);
539 	rt_genid_bump_ipv6(net);
540 }
541 
fnhe_genid(const struct net * net)542 static inline int fnhe_genid(const struct net *net)
543 {
544 	return atomic_read(&net->fnhe_genid);
545 }
546 
fnhe_genid_bump(struct net * net)547 static inline void fnhe_genid_bump(struct net *net)
548 {
549 	atomic_inc(&net->fnhe_genid);
550 }
551 
552 #ifdef CONFIG_NET
553 void net_ns_init(void);
554 #else
net_ns_init(void)555 static inline void net_ns_init(void) {}
556 #endif
557 
558 #endif /* __NET_NET_NAMESPACE_H */
559