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 };
 114
 115 /*
 116  * ifindex generation is per-net namespace, and loopback is
 117  * always the 1st device in ns (see net_dev_init), thus any
 118  * loopback device should get ifindex 1
 119  */
 120
 121 #define LOOPBACK_IFINDEX        1
 122
 123 #include <linux/seq_file_net.h>
 124
 125 /* Init's network namespace */
 126 extern struct net init_net;
 127
 128 #ifdef CONFIG_NET
 129 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
 130
 131 #else /* CONFIG_NET */
 132 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
 133 {
 134         /* There is nothing to copy so this is a noop */
 135         return net_ns;
 136 }
 137 #endif /* CONFIG_NET */
 138
 139
 140 extern struct list_head net_namespace_list;
 141
 142 extern struct net *get_net_ns_by_pid(pid_t pid);
 143 extern struct net *get_net_ns_by_fd(int pid);
 144
 145 #ifdef CONFIG_NET_NS
 146 extern void __put_net(struct net *net);
 147
 148 static inline struct net *get_net(struct net *net)
 149 {
 150         atomic_inc(&net->count);
 151         return net;
 152 }
 153
 154 static inline struct net *maybe_get_net(struct net *net)
 155 {
 156         /* Used when we know struct net exists but we
 157          * aren't guaranteed a previous reference count
 158          * exists.  If the reference count is zero this
 159          * function fails and returns NULL.
 160          */
 161         if (!atomic_inc_not_zero(&net->count))
 162                 net = NULL;
 163         return net;
 164 }
 165
 166 static inline void put_net(struct net *net)
 167 {
 168         if (atomic_dec_and_test(&net->count))
 169                 __put_net(net);
 170 }
 171
 172 static inline
 173 int net_eq(const struct net *net1, const struct net *net2)
 174 {
 175         return net1 == net2;
 176 }
 177
 178 extern void net_drop_ns(void *);
 179
 180 #else
 181
 182 static inline struct net *get_net(struct net *net)
 183 {
 184         return net;
 185 }
 186
 187 static inline void put_net(struct net *net)
 188 {
 189 }
 190
 191 static inline struct net *maybe_get_net(struct net *net)
 192 {
 193         return net;
 194 }
 195
 196 static inline
 197 int net_eq(const struct net *net1, const struct net *net2)
 198 {
 199         return 1;
 200 }
 201
 202 #define net_drop_ns NULL
 203 #endif
 204
 205
 206 #ifdef NETNS_REFCNT_DEBUG
 207 static inline struct net *hold_net(struct net *net)
 208 {
 209         if (net)
 210                 atomic_inc(&net->use_count);
 211         return net;
 212 }
 213
 214 static inline void release_net(struct net *net)
 215 {
 216         if (net)
 217                 atomic_dec(&net->use_count);
 218 }
 219 #else
 220 static inline struct net *hold_net(struct net *net)
 221 {
 222         return net;
 223 }
 224
 225 static inline void release_net(struct net *net)
 226 {
 227 }
 228 #endif
 229
 230 #ifdef CONFIG_NET_NS
 231
 232 static inline void write_pnet(struct net **pnet, struct net *net)
 233 {
 234         *pnet = net;
 235 }
 236
 237 static inline struct net *read_pnet(struct net * const *pnet)
 238 {
 239         return *pnet;
 240 }
 241
 242 #else
 243
 244 #define write_pnet(pnet, net)   do { (void)(net);} while (0)
 245 #define read_pnet(pnet)         (&init_net)
 246
 247 #endif
 248
 249 #define for_each_net(VAR)                               \
 250         list_for_each_entry(VAR, &net_namespace_list, list)
 251
 252 #define for_each_net_rcu(VAR)                           \
 253         list_for_each_entry_rcu(VAR, &net_namespace_list, list)
 254
 255 #ifdef CONFIG_NET_NS
 256 #define __net_init
 257 #define __net_exit
 258 #define __net_initdata
 259 #else
 260 #define __net_init      __init
 261 #define __net_exit      __exit_refok
 262 #define __net_initdata  __initdata
 263 #endif
 264
 265 struct pernet_operations {
 266         struct list_head list;
 267         int (*init)(struct net *net);
 268         void (*exit)(struct net *net);
 269         void (*exit_batch)(struct list_head *net_exit_list);
 270         int *id;
 271         size_t size;
 272 };
 273
 274 /*
 275  * Use these carefully.  If you implement a network device and it
 276  * needs per network namespace operations use device pernet operations,
 277  * otherwise use pernet subsys operations.
 278  *
 279  * Network interfaces need to be removed from a dying netns _before_
 280  * subsys notifiers can be called, as most of the network code cleanup
 281  * (which is done from subsys notifiers) runs with the assumption that
 282  * dev_remove_pack has been called so no new packets will arrive during
 283  * and after the cleanup functions have been called.  dev_remove_pack
 284  * is not per namespace so instead the guarantee of no more packets
 285  * arriving in a network namespace is provided by ensuring that all
 286  * network devices and all sockets have left the network namespace
 287  * before the cleanup methods are called.
 288  *
 289  * For the longest time the ipv4 icmp code was registered as a pernet
 290  * device which caused kernel oops, and panics during network
 291  * namespace cleanup.   So please don't get this wrong.
 292  */
 293 extern int register_pernet_subsys(struct pernet_operations *);
 294 extern void unregister_pernet_subsys(struct pernet_operations *);
 295 extern int register_pernet_device(struct pernet_operations *);
 296 extern void unregister_pernet_device(struct pernet_operations *);
 297
 298 struct ctl_table;
 299 struct ctl_table_header;
 300
 301 #ifdef CONFIG_SYSCTL
 302 extern int net_sysctl_init(void);
 303 extern struct ctl_table_header *register_net_sysctl(struct net *net,
 304         const char *path, struct ctl_table *table);
 305 extern void unregister_net_sysctl_table(struct ctl_table_header *header);
 306 #else
 307 static inline int net_sysctl_init(void) { return 0; }
 308 static inline struct ctl_table_header *register_net_sysctl(struct net *net,
 309         const char *path, struct ctl_table *table)
 310 {
 311         return NULL;
 312 }
 313 static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
 314 {
 315 }
 316 #endif
 317
 318
 319 #endif /* __NET_NET_NAMESPACE_H */