net_namespace.h

  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
 47struct user_namespace;
 48struct proc_dir_entry;
 49struct net_device;
 50struct sock;
 51struct ctl_table_header;
 52struct net_generic;
 53struct uevent_sock;
 54struct netns_ipvs;
 55struct bpf_prog;
 56
 57
 58#define NETDEV_HASHBITS    8
 59#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
 60
 61struct 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	defer_free_list;
 84	struct llist_node	cleanup_list;	/* namespaces on death row */
 85
 86	struct list_head ptype_all;
 87	struct list_head ptype_specific;
 88
 89#ifdef CONFIG_KEYS
 90	struct key_tag		*key_domain;	/* Key domain of operation tag */
 91#endif
 92	struct user_namespace   *user_ns;	/* Owning user namespace */
 93	struct ucounts		*ucounts;
 94	struct idr		netns_ids;
 95
 96	struct ns_common	ns;
 97	struct ref_tracker_dir  refcnt_tracker;
 98	struct ref_tracker_dir  notrefcnt_tracker; /* tracker for objects not
 99						    * refcounted against netns
100						    */
101	struct list_head 	dev_base_head;
102	struct proc_dir_entry 	*proc_net;
103	struct proc_dir_entry 	*proc_net_stat;
104
105#ifdef CONFIG_SYSCTL
106	struct ctl_table_set	sysctls;
107#endif
108
109	struct sock 		*rtnl;			/* rtnetlink socket */
110	struct sock		*genl_sock;
111
112	struct uevent_sock	*uevent_sock;		/* uevent socket */
113
114	struct hlist_head 	*dev_name_head;
115	struct hlist_head	*dev_index_head;
116	struct xarray		dev_by_index;
117	struct raw_notifier_head	netdev_chain;
118
119	/* Note that @hash_mix can be read millions times per second,
120	 * it is critical that it is on a read_mostly cache line.
121	 */
122	u32			hash_mix;
123
124	struct net_device       *loopback_dev;          /* The loopback */
125
126	/* core fib_rules */
127	struct list_head	rules_ops;
128
129	struct netns_core	core;
130	struct netns_mib	mib;
131	struct netns_packet	packet;
132#if IS_ENABLED(CONFIG_UNIX)
133	struct netns_unix	unx;
134#endif
135	struct netns_nexthop	nexthop;
136	struct netns_ipv4	ipv4;
137#if IS_ENABLED(CONFIG_IPV6)
138	struct netns_ipv6	ipv6;
139#endif
140#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
141	struct netns_ieee802154_lowpan	ieee802154_lowpan;
142#endif
143#if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
144	struct netns_sctp	sctp;
145#endif
146#ifdef CONFIG_NETFILTER
147	struct netns_nf		nf;
148#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
149	struct netns_ct		ct;
150#endif
151#if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
152	struct netns_nftables	nft;
153#endif
154#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
155	struct netns_ft ft;
156#endif
157#endif
158#ifdef CONFIG_WEXT_CORE
159	struct sk_buff_head	wext_nlevents;
160#endif
161	struct net_generic __rcu	*gen;
162
163	/* Used to store attached BPF programs */
164	struct netns_bpf	bpf;
165
166	/* Note : following structs are cache line aligned */
167#ifdef CONFIG_XFRM
168	struct netns_xfrm	xfrm;
169#endif
170
171	u64			net_cookie; /* written once */
172
173#if IS_ENABLED(CONFIG_IP_VS)
174	struct netns_ipvs	*ipvs;
175#endif
176#if IS_ENABLED(CONFIG_MPLS)
177	struct netns_mpls	mpls;
178#endif
179#if IS_ENABLED(CONFIG_CAN)
180	struct netns_can	can;
181#endif
182#ifdef CONFIG_XDP_SOCKETS
183	struct netns_xdp	xdp;
184#endif
185#if IS_ENABLED(CONFIG_MCTP)
186	struct netns_mctp	mctp;
187#endif
188#if IS_ENABLED(CONFIG_CRYPTO_USER)
189	struct sock		*crypto_nlsk;
190#endif
191	struct sock		*diag_nlsk;
192#if IS_ENABLED(CONFIG_SMC)
193	struct netns_smc	smc;
194#endif
195#ifdef CONFIG_DEBUG_NET_SMALL_RTNL
196	/* Move to a better place when the config guard is removed. */
197	struct mutex		rtnl_mutex;
198#endif
199} __randomize_layout;
200
201#include <linux/seq_file_net.h>
202
203/* Init's network namespace */
204extern struct net init_net;
205
206#ifdef CONFIG_NET_NS
207struct net *copy_net_ns(u64 flags, struct user_namespace *user_ns,
208			struct net *old_net);
209
210void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
211
212void net_ns_barrier(void);
213
214struct ns_common *get_net_ns(struct ns_common *ns);
215struct net *get_net_ns_by_fd(int fd);
216extern struct task_struct *cleanup_net_task;
217
218#else /* CONFIG_NET_NS */
219#include <linux/sched.h>
220#include <linux/nsproxy.h>
221static inline struct net *copy_net_ns(u64 flags,
222	struct user_namespace *user_ns, struct net *old_net)
223{
224	if (flags & CLONE_NEWNET)
225		return ERR_PTR(-EINVAL);
226	return old_net;
227}
228
229static inline void net_ns_get_ownership(const struct net *net,
230					kuid_t *uid, kgid_t *gid)
231{
232	*uid = GLOBAL_ROOT_UID;
233	*gid = GLOBAL_ROOT_GID;
234}
235
236static inline void net_ns_barrier(void) {}
237
238static inline struct ns_common *get_net_ns(struct ns_common *ns)
239{
240	return ERR_PTR(-EINVAL);
241}
242
243static inline struct net *get_net_ns_by_fd(int fd)
244{
245	return ERR_PTR(-EINVAL);
246}
247#endif /* CONFIG_NET_NS */
248
249
250extern struct list_head net_namespace_list;
251
252struct net *get_net_ns_by_pid(pid_t pid);
253
254#ifdef CONFIG_SYSCTL
255void ipx_register_sysctl(void);
256void ipx_unregister_sysctl(void);
257#else
258#define ipx_register_sysctl()
259#define ipx_unregister_sysctl()
260#endif
261
262#ifdef CONFIG_NET_NS
263void __put_net(struct net *net);
264
265static inline struct net *to_net_ns(struct ns_common *ns)
266{
267	return container_of(ns, struct net, ns);
268}
269
270/* Try using get_net_track() instead */
271static inline struct net *get_net(struct net *net)
272{
273	ns_ref_inc(net);
274	return net;
275}
276
277static inline struct net *maybe_get_net(struct net *net)
278{
279	/* Used when we know struct net exists but we
280	 * aren't guaranteed a previous reference count
281	 * exists.  If the reference count is zero this
282	 * function fails and returns NULL.
283	 */
284	if (!ns_ref_get(net))
285		net = NULL;
286	return net;
287}
288
289/* Try using put_net_track() instead */
290static inline void put_net(struct net *net)
291{
292	if (ns_ref_put(net))
293		__put_net(net);
294}
295
296static inline
297int net_eq(const struct net *net1, const struct net *net2)
298{
299	return net1 == net2;
300}
301
302static inline int check_net(const struct net *net)
303{
304	return ns_ref_read(net) != 0;
305}
306
307void net_drop_ns(void *);
308void net_passive_dec(struct net *net);
309
310#else
311
312static inline struct net *get_net(struct net *net)
313{
314	return net;
315}
316
317static inline void put_net(struct net *net)
318{
319}
320
321static inline struct net *maybe_get_net(struct net *net)
322{
323	return net;
324}
325
326static inline
327int net_eq(const struct net *net1, const struct net *net2)
328{
329	return 1;
330}
331
332static inline int check_net(const struct net *net)
333{
334	return 1;
335}
336
337#define net_drop_ns NULL
338
339static inline void net_passive_dec(struct net *net)
340{
341	refcount_dec(&net->passive);
342}
343#endif
344
345static inline void net_passive_inc(struct net *net)
346{
347	refcount_inc(&net->passive);
348}
349
350/* Returns true if the netns initialization is completed successfully */
351static inline bool net_initialized(const struct net *net)
352{
353	return READ_ONCE(net->list.next);
354}
355
356static inline void __netns_tracker_alloc(struct net *net,
357					 netns_tracker *tracker,
358					 bool refcounted,
359					 gfp_t gfp)
360{
361#ifdef CONFIG_NET_NS_REFCNT_TRACKER
362	ref_tracker_alloc(refcounted ? &net->refcnt_tracker :
363				       &net->notrefcnt_tracker,
364			  tracker, gfp);
365#endif
366}
367
368static inline void netns_tracker_alloc(struct net *net, netns_tracker *tracker,
369				       gfp_t gfp)
370{
371	__netns_tracker_alloc(net, tracker, true, gfp);
372}
373
374static inline void __netns_tracker_free(struct net *net,
375					netns_tracker *tracker,
376					bool refcounted)
377{
378#ifdef CONFIG_NET_NS_REFCNT_TRACKER
379       ref_tracker_free(refcounted ? &net->refcnt_tracker :
380				     &net->notrefcnt_tracker, tracker);
381#endif
382}
383
384static inline struct net *get_net_track(struct net *net,
385					netns_tracker *tracker, gfp_t gfp)
386{
387	get_net(net);
388	netns_tracker_alloc(net, tracker, gfp);
389	return net;
390}
391
392static inline void put_net_track(struct net *net, netns_tracker *tracker)
393{
394	__netns_tracker_free(net, tracker, true);
395	put_net(net);
396}
397
398typedef struct {
399#ifdef CONFIG_NET_NS
400	struct net __rcu *net;
401#endif
402} possible_net_t;
403
404static inline void write_pnet(possible_net_t *pnet, struct net *net)
405{
406#ifdef CONFIG_NET_NS
407	rcu_assign_pointer(pnet->net, net);
408#endif
409}
410
411static inline struct net *read_pnet(const possible_net_t *pnet)
412{
413#ifdef CONFIG_NET_NS
414	return rcu_dereference_protected(pnet->net, true);
415#else
416	return &init_net;
417#endif
418}
419
420static inline struct net *read_pnet_rcu(const possible_net_t *pnet)
421{
422#ifdef CONFIG_NET_NS
423	return rcu_dereference(pnet->net);
424#else
425	return &init_net;
426#endif
427}
428
429/* Protected by net_rwsem */
430#define for_each_net(VAR)				\
431	list_for_each_entry(VAR, &net_namespace_list, list)
432#define for_each_net_continue_reverse(VAR)		\
433	list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
434#define for_each_net_rcu(VAR)				\
435	list_for_each_entry_rcu(VAR, &net_namespace_list, list)
436
437#ifdef CONFIG_NET_NS
438#define __net_init
439#define __net_exit
440#define __net_initdata
441#define __net_initconst
442#else
443#define __net_init	__init
444#define __net_exit	__ref
445#define __net_initdata	__initdata
446#define __net_initconst	__initconst
447#endif
448
449int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp);
450int peernet2id(const struct net *net, struct net *peer);
451bool peernet_has_id(const struct net *net, struct net *peer);
452struct net *get_net_ns_by_id(const struct net *net, int id);
453
454struct pernet_operations {
455	struct list_head list;
456	/*
457	 * Below methods are called without any exclusive locks.
458	 * More than one net may be constructed and destructed
459	 * in parallel on several cpus. Every pernet_operations
460	 * have to keep in mind all other pernet_operations and
461	 * to introduce a locking, if they share common resources.
462	 *
463	 * The only time they are called with exclusive lock is
464	 * from register_pernet_subsys(), unregister_pernet_subsys()
465	 * register_pernet_device() and unregister_pernet_device().
466	 *
467	 * Exit methods using blocking RCU primitives, such as
468	 * synchronize_rcu(), should be implemented via exit_batch.
469	 * Then, destruction of a group of net requires single
470	 * synchronize_rcu() related to these pernet_operations,
471	 * instead of separate synchronize_rcu() for every net.
472	 * Please, avoid synchronize_rcu() at all, where it's possible.
473	 *
474	 * Note that a combination of pre_exit() and exit() can
475	 * be used, since a synchronize_rcu() is guaranteed between
476	 * the calls.
477	 */
478	int (*init)(struct net *net);
479	void (*pre_exit)(struct net *net);
480	void (*exit)(struct net *net);
481	void (*exit_batch)(struct list_head *net_exit_list);
482	/* Following method is called with RTNL held. */
483	void (*exit_rtnl)(struct net *net,
484			  struct list_head *dev_kill_list);
485	unsigned int * const id;
486	const size_t size;
487};
488
489/*
490 * Use these carefully.  If you implement a network device and it
491 * needs per network namespace operations use device pernet operations,
492 * otherwise use pernet subsys operations.
493 *
494 * Network interfaces need to be removed from a dying netns _before_
495 * subsys notifiers can be called, as most of the network code cleanup
496 * (which is done from subsys notifiers) runs with the assumption that
497 * dev_remove_pack has been called so no new packets will arrive during
498 * and after the cleanup functions have been called.  dev_remove_pack
499 * is not per namespace so instead the guarantee of no more packets
500 * arriving in a network namespace is provided by ensuring that all
501 * network devices and all sockets have left the network namespace
502 * before the cleanup methods are called.
503 *
504 * For the longest time the ipv4 icmp code was registered as a pernet
505 * device which caused kernel oops, and panics during network
506 * namespace cleanup.   So please don't get this wrong.
507 */
508int register_pernet_subsys(struct pernet_operations *);
509void unregister_pernet_subsys(struct pernet_operations *);
510int register_pernet_device(struct pernet_operations *);
511void unregister_pernet_device(struct pernet_operations *);
512
513struct ctl_table;
514
515#define register_net_sysctl(net, path, table)	\
516	register_net_sysctl_sz(net, path, table, ARRAY_SIZE(table))
517#ifdef CONFIG_SYSCTL
518int net_sysctl_init(void);
519struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,
520					     struct ctl_table *table, size_t table_size);
521void unregister_net_sysctl_table(struct ctl_table_header *header);
522#else
523static inline int net_sysctl_init(void) { return 0; }
524static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,
525	const char *path, struct ctl_table *table, size_t table_size)
526{
527	return NULL;
528}
529static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
530{
531}
532#endif
533
534static inline int rt_genid_ipv4(const struct net *net)
535{
536	return atomic_read(&net->ipv4.rt_genid);
537}
538
539#if IS_ENABLED(CONFIG_IPV6)
540static inline int rt_genid_ipv6(const struct net *net)
541{
542	return atomic_read(&net->ipv6.fib6_sernum);
543}
544#endif
545
546static inline void rt_genid_bump_ipv4(struct net *net)
547{
548	atomic_inc(&net->ipv4.rt_genid);
549}
550
551extern void (*__fib6_flush_trees)(struct net *net);
552static inline void rt_genid_bump_ipv6(struct net *net)
553{
554	if (__fib6_flush_trees)
555		__fib6_flush_trees(net);
556}
557
558#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
559static inline struct netns_ieee802154_lowpan *
560net_ieee802154_lowpan(struct net *net)
561{
562	return &net->ieee802154_lowpan;
563}
564#endif
565
566/* For callers who don't really care about whether it's IPv4 or IPv6 */
567static inline void rt_genid_bump_all(struct net *net)
568{
569	rt_genid_bump_ipv4(net);
570	rt_genid_bump_ipv6(net);
571}
572
573static inline int fnhe_genid(const struct net *net)
574{
575	return atomic_read(&net->fnhe_genid);
576}
577
578static inline void fnhe_genid_bump(struct net *net)
579{
580	atomic_inc(&net->fnhe_genid);
581}
582
583#ifdef CONFIG_NET
584void net_ns_init(void);
585#else
586static inline void net_ns_init(void) {}
587#endif
588
589#endif /* __NET_NET_NAMESPACE_H */