1 /*
2  * Operations on the network namespace
3  */
4 #ifndef __NET_NET_NAMESPACE_H
5 #define __NET_NET_NAMESPACE_H
6 
7 #include <linux/atomic.h>
8 #include <linux/workqueue.h>
9 #include <linux/list.h>
10 #include <linux/sysctl.h>
11 
12 #include <net/netns/core.h>
13 #include <net/netns/mib.h>
14 #include <net/netns/unix.h>
15 #include <net/netns/packet.h>
16 #include <net/netns/ipv4.h>
17 #include <net/netns/ipv6.h>
18 #include <net/netns/dccp.h>
19 #include <net/netns/x_tables.h>
20 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
21 #include <net/netns/conntrack.h>
22 #endif
23 #include <net/netns/xfrm.h>
24 
25 struct proc_dir_entry;
26 struct net_device;
27 struct sock;
28 struct ctl_table_header;
29 struct net_generic;
30 struct sock;
31 struct netns_ipvs;
32 
33 
34 #define NETDEV_HASHBITS    8
35 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
36 
37 struct net {
38 	atomic_t		passive;	/* To decided when the network
39 						 * namespace should be freed.
40 						 */
41 	atomic_t		count;		/* To decided when the network
42 						 *  namespace should be shut down.
43 						 */
44 #ifdef NETNS_REFCNT_DEBUG
45 	atomic_t		use_count;	/* To track references we
46 						 * destroy on demand
47 						 */
48 #endif
49 	spinlock_t		rules_mod_lock;
50 
51 	struct list_head	list;		/* list of network namespaces */
52 	struct list_head	cleanup_list;	/* namespaces on death row */
53 	struct list_head	exit_list;	/* Use only net_mutex */
54 
55 	struct proc_dir_entry 	*proc_net;
56 	struct proc_dir_entry 	*proc_net_stat;
57 
58 #ifdef CONFIG_SYSCTL
59 	struct ctl_table_set	sysctls;
60 #endif
61 
62 	struct sock 		*rtnl;			/* rtnetlink socket */
63 	struct sock		*genl_sock;
64 
65 	struct list_head 	dev_base_head;
66 	struct hlist_head 	*dev_name_head;
67 	struct hlist_head	*dev_index_head;
68 	unsigned int		dev_base_seq;	/* protected by rtnl_mutex */
69 
70 	/* core fib_rules */
71 	struct list_head	rules_ops;
72 
73 
74 	struct net_device       *loopback_dev;          /* The loopback */
75 	struct netns_core	core;
76 	struct netns_mib	mib;
77 	struct netns_packet	packet;
78 	struct netns_unix	unx;
79 	struct netns_ipv4	ipv4;
80 #if IS_ENABLED(CONFIG_IPV6)
81 	struct netns_ipv6	ipv6;
82 #endif
83 #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
84 	struct netns_dccp	dccp;
85 #endif
86 #ifdef CONFIG_NETFILTER
87 	struct netns_xt		xt;
88 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
89 	struct netns_ct		ct;
90 #endif
91 	struct sock		*nfnl;
92 	struct sock		*nfnl_stash;
93 #endif
94 #ifdef CONFIG_WEXT_CORE
95 	struct sk_buff_head	wext_nlevents;
96 #endif
97 	struct net_generic __rcu	*gen;
98 
99 	/* Note : following structs are cache line aligned */
100 #ifdef CONFIG_XFRM
101 	struct netns_xfrm	xfrm;
102 #endif
103 	struct netns_ipvs	*ipvs;
104 };
105 
106 
107 #include <linux/seq_file_net.h>
108 
109 /* Init's network namespace */
110 extern struct net init_net;
111 
112 #ifdef CONFIG_NET
113 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
114 
115 #else /* CONFIG_NET */
copy_net_ns(unsigned long flags,struct net * net_ns)116 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
117 {
118 	/* There is nothing to copy so this is a noop */
119 	return net_ns;
120 }
121 #endif /* CONFIG_NET */
122 
123 
124 extern struct list_head net_namespace_list;
125 
126 extern struct net *get_net_ns_by_pid(pid_t pid);
127 extern struct net *get_net_ns_by_fd(int pid);
128 
129 #ifdef CONFIG_NET_NS
130 extern void __put_net(struct net *net);
131 
get_net(struct net * net)132 static inline struct net *get_net(struct net *net)
133 {
134 	atomic_inc(&net->count);
135 	return net;
136 }
137 
maybe_get_net(struct net * net)138 static inline struct net *maybe_get_net(struct net *net)
139 {
140 	/* Used when we know struct net exists but we
141 	 * aren't guaranteed a previous reference count
142 	 * exists.  If the reference count is zero this
143 	 * function fails and returns NULL.
144 	 */
145 	if (!atomic_inc_not_zero(&net->count))
146 		net = NULL;
147 	return net;
148 }
149 
put_net(struct net * net)150 static inline void put_net(struct net *net)
151 {
152 	if (atomic_dec_and_test(&net->count))
153 		__put_net(net);
154 }
155 
156 static inline
net_eq(const struct net * net1,const struct net * net2)157 int net_eq(const struct net *net1, const struct net *net2)
158 {
159 	return net1 == net2;
160 }
161 
162 extern void net_drop_ns(void *);
163 
164 #else
165 
get_net(struct net * net)166 static inline struct net *get_net(struct net *net)
167 {
168 	return net;
169 }
170 
put_net(struct net * net)171 static inline void put_net(struct net *net)
172 {
173 }
174 
maybe_get_net(struct net * net)175 static inline struct net *maybe_get_net(struct net *net)
176 {
177 	return net;
178 }
179 
180 static inline
net_eq(const struct net * net1,const struct net * net2)181 int net_eq(const struct net *net1, const struct net *net2)
182 {
183 	return 1;
184 }
185 
186 #define net_drop_ns NULL
187 #endif
188 
189 
190 #ifdef NETNS_REFCNT_DEBUG
hold_net(struct net * net)191 static inline struct net *hold_net(struct net *net)
192 {
193 	if (net)
194 		atomic_inc(&net->use_count);
195 	return net;
196 }
197 
release_net(struct net * net)198 static inline void release_net(struct net *net)
199 {
200 	if (net)
201 		atomic_dec(&net->use_count);
202 }
203 #else
hold_net(struct net * net)204 static inline struct net *hold_net(struct net *net)
205 {
206 	return net;
207 }
208 
release_net(struct net * net)209 static inline void release_net(struct net *net)
210 {
211 }
212 #endif
213 
214 #ifdef CONFIG_NET_NS
215 
write_pnet(struct net ** pnet,struct net * net)216 static inline void write_pnet(struct net **pnet, struct net *net)
217 {
218 	*pnet = net;
219 }
220 
read_pnet(struct net * const * pnet)221 static inline struct net *read_pnet(struct net * const *pnet)
222 {
223 	return *pnet;
224 }
225 
226 #else
227 
228 #define write_pnet(pnet, net)	do { (void)(net);} while (0)
229 #define read_pnet(pnet)		(&init_net)
230 
231 #endif
232 
233 #define for_each_net(VAR)				\
234 	list_for_each_entry(VAR, &net_namespace_list, list)
235 
236 #define for_each_net_rcu(VAR)				\
237 	list_for_each_entry_rcu(VAR, &net_namespace_list, list)
238 
239 #ifdef CONFIG_NET_NS
240 #define __net_init
241 #define __net_exit
242 #define __net_initdata
243 #else
244 #define __net_init	__init
245 #define __net_exit	__exit_refok
246 #define __net_initdata	__initdata
247 #endif
248 
249 struct pernet_operations {
250 	struct list_head list;
251 	int (*init)(struct net *net);
252 	void (*exit)(struct net *net);
253 	void (*exit_batch)(struct list_head *net_exit_list);
254 	int *id;
255 	size_t size;
256 };
257 
258 /*
259  * Use these carefully.  If you implement a network device and it
260  * needs per network namespace operations use device pernet operations,
261  * otherwise use pernet subsys operations.
262  *
263  * Network interfaces need to be removed from a dying netns _before_
264  * subsys notifiers can be called, as most of the network code cleanup
265  * (which is done from subsys notifiers) runs with the assumption that
266  * dev_remove_pack has been called so no new packets will arrive during
267  * and after the cleanup functions have been called.  dev_remove_pack
268  * is not per namespace so instead the guarantee of no more packets
269  * arriving in a network namespace is provided by ensuring that all
270  * network devices and all sockets have left the network namespace
271  * before the cleanup methods are called.
272  *
273  * For the longest time the ipv4 icmp code was registered as a pernet
274  * device which caused kernel oops, and panics during network
275  * namespace cleanup.   So please don't get this wrong.
276  */
277 extern int register_pernet_subsys(struct pernet_operations *);
278 extern void unregister_pernet_subsys(struct pernet_operations *);
279 extern int register_pernet_device(struct pernet_operations *);
280 extern void unregister_pernet_device(struct pernet_operations *);
281 
282 struct ctl_path;
283 struct ctl_table;
284 struct ctl_table_header;
285 
286 extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
287 	const struct ctl_path *path, struct ctl_table *table);
288 extern struct ctl_table_header *register_net_sysctl_rotable(
289 	const struct ctl_path *path, struct ctl_table *table);
290 extern void unregister_net_sysctl_table(struct ctl_table_header *header);
291 
292 #endif /* __NET_NET_NAMESPACE_H */
293