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