include/net/net_namespace.h

   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/sctp.h>
  19 #include <net/netns/dccp.h>
  20 #include <net/netns/x_tables.h>
  21 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  22 #include <net/netns/conntrack.h>
  23 #endif
  24 #include <net/netns/xfrm.h>
  25
  26 struct proc_dir_entry;
  27 struct net_device;
  28 struct sock;
  29 struct ctl_table_header;
  30 struct net_generic;
  31 struct sock;
  32 struct netns_ipvs;
  33
  34
  35 #define NETDEV_HASHBITS    8
  36 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
  37
  38 struct net {
  39         atomic_t                passive;        /* To decided when the network
  40                                                  * namespace should be freed.
  41                                                  */
  42         atomic_t                count;          /* To decided when the network
  43                                                  *  namespace should be shut down.
  44                                                  */
  45 #ifdef NETNS_REFCNT_DEBUG
  46         atomic_t                use_count;      /* To track references we
  47                                                  * destroy on demand
  48                                                  */
  49 #endif
  50         spinlock_t              rules_mod_lock;
  51
  52         struct list_head        list;           /* list of network namespaces */
  53         struct list_head        cleanup_list;   /* namespaces on death row */
  54         struct list_head        exit_list;      /* Use only net_mutex */
  55
  56         struct proc_dir_entry   *proc_net;
  57         struct proc_dir_entry   *proc_net_stat;
  58
  59 #ifdef CONFIG_SYSCTL
  60         struct ctl_table_set    sysctls;
  61 #endif
  62
  63         struct sock             *rtnl;                  /* rtnetlink socket */
  64         struct sock             *genl_sock;
  65
  66         struct list_head        dev_base_head;
  67         struct hlist_head       *dev_name_head;
  68         struct hlist_head       *dev_index_head;
  69         unsigned int            dev_base_seq;   /* protected by rtnl_mutex */
  70         int                     ifindex;
  71
  72         /* core fib_rules */
  73         struct list_head        rules_ops;
  74
  75
  76         struct net_device       *loopback_dev;          /* The loopback */
  77         struct netns_core       core;
  78         struct netns_mib        mib;
  79         struct netns_packet     packet;
  80         struct netns_unix       unx;
  81         struct netns_ipv4       ipv4;
  82 #if IS_ENABLED(CONFIG_IPV6)
  83         struct netns_ipv6       ipv6;
  84 #endif
  85 #if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
  86         struct netns_sctp       sctp;
  87 #endif
  88 #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
  89         struct netns_dccp       dccp;
  90 #endif
  91 #ifdef CONFIG_NETFILTER
  92         struct netns_xt         xt;
  93 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  94         struct netns_ct         ct;
  95 #endif
  96 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
  97         struct netns_nf_frag    nf_frag;
  98 #endif
  99         struct sock             *nfnl;
 100         struct sock             *nfnl_stash;
 101 #endif
 102 #ifdef CONFIG_WEXT_CORE
 103         struct sk_buff_head     wext_nlevents;
 104 #endif
 105         struct net_generic __rcu        *gen;
 106
 107         /* Note : following structs are cache line aligned */
 108 #ifdef CONFIG_XFRM
 109         struct netns_xfrm       xfrm;
 110 #endif
 111         struct netns_ipvs       *ipvs;
 112         struct sock             *diag_nlsk;
 113         atomic_t                rt_genid;
 114 };
 115
 116 /*
 117  * ifindex generation is per-net namespace, and loopback is
 118  * always the 1st device in ns (see net_dev_init), thus any
 119  * loopback device should get ifindex 1
 120  */
 121
 122 #define LOOPBACK_IFINDEX        1
 123
 124 #include <linux/seq_file_net.h>
 125
 126 /* Init's network namespace */
 127 extern struct net init_net;
 128
 129 #ifdef CONFIG_NET
 130 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
 131
 132 #else /* CONFIG_NET */
 133 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
 134 {
 135         /* There is nothing to copy so this is a noop */
 136         return net_ns;
 137 }
 138 #endif /* CONFIG_NET */
 139
 140
 141 extern struct list_head net_namespace_list;
 142
 143 extern struct net *get_net_ns_by_pid(pid_t pid);
 144 extern struct net *get_net_ns_by_fd(int pid);
 145
 146 #ifdef CONFIG_NET_NS
 147 extern void __put_net(struct net *net);
 148
 149 static inline struct net *get_net(struct net *net)
 150 {
 151         atomic_inc(&net->count);
 152         return net;
 153 }
 154
 155 static inline struct net *maybe_get_net(struct net *net)
 156 {
 157         /* Used when we know struct net exists but we
 158          * aren't guaranteed a previous reference count
 159          * exists.  If the reference count is zero this
 160          * function fails and returns NULL.
 161          */
 162         if (!atomic_inc_not_zero(&net->count))
 163                 net = NULL;
 164         return net;
 165 }
 166
 167 static inline void put_net(struct net *net)
 168 {
 169         if (atomic_dec_and_test(&net->count))
 170                 __put_net(net);
 171 }
 172
 173 static inline
 174 int net_eq(const struct net *net1, const struct net *net2)
 175 {
 176         return net1 == net2;
 177 }
 178
 179 extern void net_drop_ns(void *);
 180
 181 #else
 182
 183 static inline struct net *get_net(struct net *net)
 184 {
 185         return net;
 186 }
 187
 188 static inline void put_net(struct net *net)
 189 {
 190 }
 191
 192 static inline struct net *maybe_get_net(struct net *net)
 193 {
 194         return net;
 195 }
 196
 197 static inline
 198 int net_eq(const struct net *net1, const struct net *net2)
 199 {
 200         return 1;
 201 }
 202
 203 #define net_drop_ns NULL
 204 #endif
 205
 206
 207 #ifdef NETNS_REFCNT_DEBUG
 208 static inline struct net *hold_net(struct net *net)
 209 {
 210         if (net)
 211                 atomic_inc(&net->use_count);
 212         return net;
 213 }
 214
 215 static inline void release_net(struct net *net)
 216 {
 217         if (net)
 218                 atomic_dec(&net->use_count);
 219 }
 220 #else
 221 static inline struct net *hold_net(struct net *net)
 222 {
 223         return net;
 224 }
 225
 226 static inline void release_net(struct net *net)
 227 {
 228 }
 229 #endif
 230
 231 #ifdef CONFIG_NET_NS
 232
 233 static inline void write_pnet(struct net **pnet, struct net *net)
 234 {
 235         *pnet = net;
 236 }
 237
 238 static inline struct net *read_pnet(struct net * const *pnet)
 239 {
 240         return *pnet;
 241 }
 242
 243 #else
 244
 245 #define write_pnet(pnet, net)   do { (void)(net);} while (0)
 246 #define read_pnet(pnet)         (&init_net)
 247
 248 #endif
 249
 250 #define for_each_net(VAR)                               \
 251         list_for_each_entry(VAR, &net_namespace_list, list)
 252
 253 #define for_each_net_rcu(VAR)                           \
 254         list_for_each_entry_rcu(VAR, &net_namespace_list, list)
 255
 256 #ifdef CONFIG_NET_NS
 257 #define __net_init
 258 #define __net_exit
 259 #define __net_initdata
 260 #else
 261 #define __net_init      __init
 262 #define __net_exit      __exit_refok
 263 #define __net_initdata  __initdata
 264 #endif
 265
 266 struct pernet_operations {
 267         struct list_head list;
 268         int (*init)(struct net *net);
 269         void (*exit)(struct net *net);
 270         void (*exit_batch)(struct list_head *net_exit_list);
 271         int *id;
 272         size_t size;
 273 };
 274
 275 /*
 276  * Use these carefully.  If you implement a network device and it
 277  * needs per network namespace operations use device pernet operations,
 278  * otherwise use pernet subsys operations.
 279  *
 280  * Network interfaces need to be removed from a dying netns _before_
 281  * subsys notifiers can be called, as most of the network code cleanup
 282  * (which is done from subsys notifiers) runs with the assumption that
 283  * dev_remove_pack has been called so no new packets will arrive during
 284  * and after the cleanup functions have been called.  dev_remove_pack
 285  * is not per namespace so instead the guarantee of no more packets
 286  * arriving in a network namespace is provided by ensuring that all
 287  * network devices and all sockets have left the network namespace
 288  * before the cleanup methods are called.
 289  *
 290  * For the longest time the ipv4 icmp code was registered as a pernet
 291  * device which caused kernel oops, and panics during network
 292  * namespace cleanup.   So please don't get this wrong.
 293  */
 294 extern int register_pernet_subsys(struct pernet_operations *);
 295 extern void unregister_pernet_subsys(struct pernet_operations *);
 296 extern int register_pernet_device(struct pernet_operations *);
 297 extern void unregister_pernet_device(struct pernet_operations *);
 298
 299 struct ctl_table;
 300 struct ctl_table_header;
 301
 302 #ifdef CONFIG_SYSCTL
 303 extern int net_sysctl_init(void);
 304 extern struct ctl_table_header *register_net_sysctl(struct net *net,
 305         const char *path, struct ctl_table *table);
 306 extern void unregister_net_sysctl_table(struct ctl_table_header *header);
 307 #else
 308 static inline int net_sysctl_init(void) { return 0; }
 309 static inline struct ctl_table_header *register_net_sysctl(struct net *net,
 310         const char *path, struct ctl_table *table)
 311 {
 312         return NULL;
 313 }
 314 static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
 315 {
 316 }
 317 #endif
 318
 319 static inline int rt_genid(struct net *net)
 320 {
 321         return atomic_read(&net->rt_genid);
 322 }
 323
 324 static inline void rt_genid_bump(struct net *net)
 325 {
 326         atomic_inc(&net->rt_genid);
 327 }
 328
 329 #endif /* __NET_NET_NAMESPACE_H */