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