include/linux/netfilter.h

   1 #ifndef __LINUX_NETFILTER_H
   2 #define __LINUX_NETFILTER_H
   3
   4 #include <linux/init.h>
   5 #include <linux/skbuff.h>
   6 #include <linux/net.h>
   7 #include <linux/if.h>
   8 #include <linux/in.h>
   9 #include <linux/in6.h>
  10 #include <linux/wait.h>
  11 #include <linux/list.h>
  12 #include <linux/static_key.h>
  13 #include <linux/netfilter_defs.h>
  14 #include <linux/netdevice.h>
  15 #include <net/net_namespace.h>
  16
  17 #ifdef CONFIG_NETFILTER
  18 static inline int NF_DROP_GETERR(int verdict)
  19 {
  20         return -(verdict >> NF_VERDICT_QBITS);
  21 }
  22
  23 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  24                                    const union nf_inet_addr *a2)
  25 {
  26         return a1->all[0] == a2->all[0] &&
  27                a1->all[1] == a2->all[1] &&
  28                a1->all[2] == a2->all[2] &&
  29                a1->all[3] == a2->all[3];
  30 }
  31
  32 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
  33                                      union nf_inet_addr *result,
  34                                      const union nf_inet_addr *mask)
  35 {
  36         result->all[0] = a1->all[0] & mask->all[0];
  37         result->all[1] = a1->all[1] & mask->all[1];
  38         result->all[2] = a1->all[2] & mask->all[2];
  39         result->all[3] = a1->all[3] & mask->all[3];
  40 }
  41
  42 int netfilter_init(void);
  43
  44 struct sk_buff;
  45
  46 struct nf_hook_ops;
  47
  48 struct sock;
  49
  50 struct nf_hook_state {
  51         unsigned int hook;
  52         u_int8_t pf;
  53         struct net_device *in;
  54         struct net_device *out;
  55         struct sock *sk;
  56         struct net *net;
  57         int (*okfn)(struct net *, struct sock *, struct sk_buff *);
  58 };
  59
  60 typedef unsigned int nf_hookfn(void *priv,
  61                                struct sk_buff *skb,
  62                                const struct nf_hook_state *state);
  63 struct nf_hook_ops {
  64         struct list_head        list;
  65
  66         /* User fills in from here down. */
  67         nf_hookfn               *hook;
  68         struct net_device       *dev;
  69         void                    *priv;
  70         u_int8_t                pf;
  71         unsigned int            hooknum;
  72         /* Hooks are ordered in ascending priority. */
  73         int                     priority;
  74 };
  75
  76 struct nf_hook_entry {
  77         struct nf_hook_entry __rcu      *next;
  78         nf_hookfn                       *hook;
  79         void                            *priv;
  80         const struct nf_hook_ops        *orig_ops;
  81 };
  82
  83 static inline void
  84 nf_hook_entry_init(struct nf_hook_entry *entry, const struct nf_hook_ops *ops)
  85 {
  86         entry->next = NULL;
  87         entry->hook = ops->hook;
  88         entry->priv = ops->priv;
  89         entry->orig_ops = ops;
  90 }
  91
  92 static inline int
  93 nf_hook_entry_priority(const struct nf_hook_entry *entry)
  94 {
  95         return entry->orig_ops->priority;
  96 }
  97
  98 static inline int
  99 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
 100                      struct nf_hook_state *state)
 101 {
 102         return entry->hook(entry->priv, skb, state);
 103 }
 104
 105 static inline const struct nf_hook_ops *
 106 nf_hook_entry_ops(const struct nf_hook_entry *entry)
 107 {
 108         return entry->orig_ops;
 109 }
 110
 111 static inline void nf_hook_state_init(struct nf_hook_state *p,
 112                                       unsigned int hook,
 113                                       u_int8_t pf,
 114                                       struct net_device *indev,
 115                                       struct net_device *outdev,
 116                                       struct sock *sk,
 117                                       struct net *net,
 118                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 119 {
 120         p->hook = hook;
 121         p->pf = pf;
 122         p->in = indev;
 123         p->out = outdev;
 124         p->sk = sk;
 125         p->net = net;
 126         p->okfn = okfn;
 127 }
 128
 129
 130
 131 struct nf_sockopt_ops {
 132         struct list_head list;
 133
 134         u_int8_t pf;
 135
 136         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 137         int set_optmin;
 138         int set_optmax;
 139         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 140 #ifdef CONFIG_COMPAT
 141         int (*compat_set)(struct sock *sk, int optval,
 142                         void __user *user, unsigned int len);
 143 #endif
 144         int get_optmin;
 145         int get_optmax;
 146         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 147 #ifdef CONFIG_COMPAT
 148         int (*compat_get)(struct sock *sk, int optval,
 149                         void __user *user, int *len);
 150 #endif
 151         /* Use the module struct to lock set/get code in place */
 152         struct module *owner;
 153 };
 154
 155 /* Function to register/unregister hook points. */
 156 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 157 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 158 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 159                           unsigned int n);
 160 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 161                              unsigned int n);
 162
 163 int nf_register_hook(struct nf_hook_ops *reg);
 164 void nf_unregister_hook(struct nf_hook_ops *reg);
 165 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 166 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 167 int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 168 void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 169
 170 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 171    need to check permissions yourself! */
 172 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 173 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 174
 175 #ifdef HAVE_JUMP_LABEL
 176 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 177 #endif
 178
 179 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 180                  struct nf_hook_entry *entry);
 181
 182 /**
 183  *      nf_hook - call a netfilter hook
 184  *
 185  *      Returns 1 if the hook has allowed the packet to pass.  The function
 186  *      okfn must be invoked by the caller in this case.  Any other return
 187  *      value indicates the packet has been consumed by the hook.
 188  */
 189 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 190                           struct sock *sk, struct sk_buff *skb,
 191                           struct net_device *indev, struct net_device *outdev,
 192                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 193 {
 194         struct nf_hook_entry *hook_head;
 195         int ret = 1;
 196
 197 #ifdef HAVE_JUMP_LABEL
 198         if (__builtin_constant_p(pf) &&
 199             __builtin_constant_p(hook) &&
 200             !static_key_false(&nf_hooks_needed[pf][hook]))
 201                 return 1;
 202 #endif
 203
 204         rcu_read_lock();
 205         hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
 206         if (hook_head) {
 207                 struct nf_hook_state state;
 208
 209                 nf_hook_state_init(&state, hook, pf, indev, outdev,
 210                                    sk, net, okfn);
 211
 212                 ret = nf_hook_slow(skb, &state, hook_head);
 213         }
 214         rcu_read_unlock();
 215
 216         return ret;
 217 }
 218
 219 /* Activate hook; either okfn or kfree_skb called, unless a hook
 220    returns NF_STOLEN (in which case, it's up to the hook to deal with
 221    the consequences).
 222
 223    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 224    accepted.
 225 */
 226
 227 /* RR:
 228    > I don't want nf_hook to return anything because people might forget
 229    > about async and trust the return value to mean "packet was ok".
 230
 231    AK:
 232    Just document it clearly, then you can expect some sense from kernel
 233    coders :)
 234 */
 235
 236 static inline int
 237 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 238              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 239              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 240              bool cond)
 241 {
 242         int ret;
 243
 244         if (!cond ||
 245             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
 246                 ret = okfn(net, sk, skb);
 247         return ret;
 248 }
 249
 250 static inline int
 251 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 252         struct net_device *in, struct net_device *out,
 253         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 254 {
 255         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
 256         if (ret == 1)
 257                 ret = okfn(net, sk, skb);
 258         return ret;
 259 }
 260
 261 /* Call setsockopt() */
 262 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 263                   unsigned int len);
 264 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 265                   int *len);
 266 #ifdef CONFIG_COMPAT
 267 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 268                 char __user *opt, unsigned int len);
 269 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 270                 char __user *opt, int *len);
 271 #endif
 272
 273 /* Call this before modifying an existing packet: ensures it is
 274    modifiable and linear to the point you care about (writable_len).
 275    Returns true or false. */
 276 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 277
 278 struct flowi;
 279 struct nf_queue_entry;
 280
 281 struct nf_afinfo {
 282         unsigned short  family;
 283         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 284                                     unsigned int dataoff, u_int8_t protocol);
 285         __sum16         (*checksum_partial)(struct sk_buff *skb,
 286                                             unsigned int hook,
 287                                             unsigned int dataoff,
 288                                             unsigned int len,
 289                                             u_int8_t protocol);
 290         int             (*route)(struct net *net, struct dst_entry **dst,
 291                                  struct flowi *fl, bool strict);
 292         void            (*saveroute)(const struct sk_buff *skb,
 293                                      struct nf_queue_entry *entry);
 294         int             (*reroute)(struct net *net, struct sk_buff *skb,
 295                                    const struct nf_queue_entry *entry);
 296         int             route_key_size;
 297 };
 298
 299 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 300 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 301 {
 302         return rcu_dereference(nf_afinfo[family]);
 303 }
 304
 305 static inline __sum16
 306 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 307             u_int8_t protocol, unsigned short family)
 308 {
 309         const struct nf_afinfo *afinfo;
 310         __sum16 csum = 0;
 311
 312         rcu_read_lock();
 313         afinfo = nf_get_afinfo(family);
 314         if (afinfo)
 315                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 316         rcu_read_unlock();
 317         return csum;
 318 }
 319
 320 static inline __sum16
 321 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 322                     unsigned int dataoff, unsigned int len,
 323                     u_int8_t protocol, unsigned short family)
 324 {
 325         const struct nf_afinfo *afinfo;
 326         __sum16 csum = 0;
 327
 328         rcu_read_lock();
 329         afinfo = nf_get_afinfo(family);
 330         if (afinfo)
 331                 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 332                                                 protocol);
 333         rcu_read_unlock();
 334         return csum;
 335 }
 336
 337 int nf_register_afinfo(const struct nf_afinfo *afinfo);
 338 void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 339
 340 #include <net/flow.h>
 341 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 342
 343 static inline void
 344 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 345 {
 346 #ifdef CONFIG_NF_NAT_NEEDED
 347         void (*decodefn)(struct sk_buff *, struct flowi *);
 348
 349         rcu_read_lock();
 350         decodefn = rcu_dereference(nf_nat_decode_session_hook);
 351         if (decodefn)
 352                 decodefn(skb, fl);
 353         rcu_read_unlock();
 354 #endif
 355 }
 356
 357 #else /* !CONFIG_NETFILTER */
 358 static inline int
 359 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 360              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 361              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 362              bool cond)
 363 {
 364         return okfn(net, sk, skb);
 365 }
 366
 367 static inline int
 368 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 369         struct sk_buff *skb, struct net_device *in, struct net_device *out,
 370         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 371 {
 372         return okfn(net, sk, skb);
 373 }
 374
 375 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 376                           struct sock *sk, struct sk_buff *skb,
 377                           struct net_device *indev, struct net_device *outdev,
 378                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 379 {
 380         return 1;
 381 }
 382 struct flowi;
 383 static inline void
 384 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 385 {
 386 }
 387 #endif /*CONFIG_NETFILTER*/
 388
 389 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 390 #include <linux/netfilter/nf_conntrack_zones_common.h>
 391
 392 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 393 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 394 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 395 #else
 396 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 397 #endif
 398
 399 struct nf_conn;
 400 enum ip_conntrack_info;
 401 struct nlattr;
 402
 403 struct nfnl_ct_hook {
 404         struct nf_conn *(*get_ct)(const struct sk_buff *skb,
 405                                   enum ip_conntrack_info *ctinfo);
 406         size_t (*build_size)(const struct nf_conn *ct);
 407         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 408                      enum ip_conntrack_info ctinfo,
 409                      u_int16_t ct_attr, u_int16_t ct_info_attr);
 410         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 411         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 412                              u32 portid, u32 report);
 413         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 414                            enum ip_conntrack_info ctinfo, s32 off);
 415 };
 416 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 417
 418 /**
 419  * nf_skb_duplicated - TEE target has sent a packet
 420  *
 421  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 422  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 423  *
 424  * This is used by xtables TEE target to prevent the duplicated skb from
 425  * being duplicated again.
 426  */
 427 DECLARE_PER_CPU(bool, nf_skb_duplicated);
 428
 429 #endif /*__LINUX_NETFILTER_H*/