include/linux/netfilter.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_NETFILTER_H
   3 #define __LINUX_NETFILTER_H
   4
   5 #include <linux/init.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/net.h>
   8 #include <linux/if.h>
   9 #include <linux/in.h>
  10 #include <linux/in6.h>
  11 #include <linux/wait.h>
  12 #include <linux/list.h>
  13 #include <linux/static_key.h>
  14 #include <linux/netfilter_defs.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/sockptr.h>
  17 #include <net/net_namespace.h>
  18
  19 static inline int NF_DROP_GETERR(int verdict)
  20 {
  21         return -(verdict >> NF_VERDICT_QBITS);
  22 }
  23
  24 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  25                                    const union nf_inet_addr *a2)
  26 {
  27 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  28         const unsigned long *ul1 = (const unsigned long *)a1;
  29         const unsigned long *ul2 = (const unsigned long *)a2;
  30
  31         return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
  32 #else
  33         return a1->all[0] == a2->all[0] &&
  34                a1->all[1] == a2->all[1] &&
  35                a1->all[2] == a2->all[2] &&
  36                a1->all[3] == a2->all[3];
  37 #endif
  38 }
  39
  40 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
  41                                      union nf_inet_addr *result,
  42                                      const union nf_inet_addr *mask)
  43 {
  44 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  45         const unsigned long *ua = (const unsigned long *)a1;
  46         unsigned long *ur = (unsigned long *)result;
  47         const unsigned long *um = (const unsigned long *)mask;
  48
  49         ur[0] = ua[0] & um[0];
  50         ur[1] = ua[1] & um[1];
  51 #else
  52         result->all[0] = a1->all[0] & mask->all[0];
  53         result->all[1] = a1->all[1] & mask->all[1];
  54         result->all[2] = a1->all[2] & mask->all[2];
  55         result->all[3] = a1->all[3] & mask->all[3];
  56 #endif
  57 }
  58
  59 int netfilter_init(void);
  60
  61 struct sk_buff;
  62
  63 struct nf_hook_ops;
  64
  65 struct sock;
  66
  67 struct nf_hook_state {
  68         u8 hook;
  69         u8 pf;
  70         struct net_device *in;
  71         struct net_device *out;
  72         struct sock *sk;
  73         struct net *net;
  74         int (*okfn)(struct net *, struct sock *, struct sk_buff *);
  75 };
  76
  77 typedef unsigned int nf_hookfn(void *priv,
  78                                struct sk_buff *skb,
  79                                const struct nf_hook_state *state);
  80 enum nf_hook_ops_type {
  81         NF_HOOK_OP_UNDEFINED,
  82         NF_HOOK_OP_NF_TABLES,
  83 };
  84
  85 struct nf_hook_ops {
  86         /* User fills in from here down. */
  87         nf_hookfn               *hook;
  88         struct net_device       *dev;
  89         void                    *priv;
  90         u8                      pf;
  91         enum nf_hook_ops_type   hook_ops_type:8;
  92         unsigned int            hooknum;
  93         /* Hooks are ordered in ascending priority. */
  94         int                     priority;
  95 };
  96
  97 struct nf_hook_entry {
  98         nf_hookfn                       *hook;
  99         void                            *priv;
 100 };
 101
 102 struct nf_hook_entries_rcu_head {
 103         struct rcu_head head;
 104         void    *allocation;
 105 };
 106
 107 struct nf_hook_entries {
 108         u16                             num_hook_entries;
 109         /* padding */
 110         struct nf_hook_entry            hooks[];
 111
 112         /* trailer: pointers to original orig_ops of each hook,
 113          * followed by rcu_head and scratch space used for freeing
 114          * the structure via call_rcu.
 115          *
 116          *   This is not part of struct nf_hook_entry since its only
 117          *   needed in slow path (hook register/unregister):
 118          * const struct nf_hook_ops     *orig_ops[]
 119          *
 120          *   For the same reason, we store this at end -- its
 121          *   only needed when a hook is deleted, not during
 122          *   packet path processing:
 123          * struct nf_hook_entries_rcu_head     head
 124          */
 125 };
 126
 127 #ifdef CONFIG_NETFILTER
 128 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
 129 {
 130         unsigned int n = e->num_hook_entries;
 131         const void *hook_end;
 132
 133         hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */
 134
 135         return (struct nf_hook_ops **)hook_end;
 136 }
 137
 138 static inline int
 139 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
 140                      struct nf_hook_state *state)
 141 {
 142         return entry->hook(entry->priv, skb, state);
 143 }
 144
 145 static inline void nf_hook_state_init(struct nf_hook_state *p,
 146                                       unsigned int hook,
 147                                       u_int8_t pf,
 148                                       struct net_device *indev,
 149                                       struct net_device *outdev,
 150                                       struct sock *sk,
 151                                       struct net *net,
 152                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 153 {
 154         p->hook = hook;
 155         p->pf = pf;
 156         p->in = indev;
 157         p->out = outdev;
 158         p->sk = sk;
 159         p->net = net;
 160         p->okfn = okfn;
 161 }
 162
 163
 164
 165 struct nf_sockopt_ops {
 166         struct list_head list;
 167
 168         u_int8_t pf;
 169
 170         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 171         int set_optmin;
 172         int set_optmax;
 173         int (*set)(struct sock *sk, int optval, sockptr_t arg,
 174                    unsigned int len);
 175         int get_optmin;
 176         int get_optmax;
 177         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 178         /* Use the module struct to lock set/get code in place */
 179         struct module *owner;
 180 };
 181
 182 /* Function to register/unregister hook points. */
 183 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 184 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 185 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 186                           unsigned int n);
 187 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 188                              unsigned int n);
 189
 190 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 191    need to check permissions yourself! */
 192 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 193 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 194
 195 #ifdef CONFIG_JUMP_LABEL
 196 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 197 #endif
 198
 199 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 200                  const struct nf_hook_entries *e, unsigned int i);
 201
 202 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
 203                        const struct nf_hook_entries *e);
 204 /**
 205  *      nf_hook - call a netfilter hook
 206  *
 207  *      Returns 1 if the hook has allowed the packet to pass.  The function
 208  *      okfn must be invoked by the caller in this case.  Any other return
 209  *      value indicates the packet has been consumed by the hook.
 210  */
 211 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 212                           struct sock *sk, struct sk_buff *skb,
 213                           struct net_device *indev, struct net_device *outdev,
 214                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 215 {
 216         struct nf_hook_entries *hook_head = NULL;
 217         int ret = 1;
 218
 219 #ifdef CONFIG_JUMP_LABEL
 220         if (__builtin_constant_p(pf) &&
 221             __builtin_constant_p(hook) &&
 222             !static_key_false(&nf_hooks_needed[pf][hook]))
 223                 return 1;
 224 #endif
 225
 226         rcu_read_lock();
 227         switch (pf) {
 228         case NFPROTO_IPV4:
 229                 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
 230                 break;
 231         case NFPROTO_IPV6:
 232                 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
 233                 break;
 234         case NFPROTO_ARP:
 235 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 236                 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp)))
 237                         break;
 238                 hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
 239 #endif
 240                 break;
 241         case NFPROTO_BRIDGE:
 242 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 243                 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]);
 244 #endif
 245                 break;
 246 #if IS_ENABLED(CONFIG_DECNET)
 247         case NFPROTO_DECNET:
 248                 hook_head = rcu_dereference(net->nf.hooks_decnet[hook]);
 249                 break;
 250 #endif
 251         default:
 252                 WARN_ON_ONCE(1);
 253                 break;
 254         }
 255
 256         if (hook_head) {
 257                 struct nf_hook_state state;
 258
 259                 nf_hook_state_init(&state, hook, pf, indev, outdev,
 260                                    sk, net, okfn);
 261
 262                 ret = nf_hook_slow(skb, &state, hook_head, 0);
 263         }
 264         rcu_read_unlock();
 265
 266         return ret;
 267 }
 268
 269 /* Activate hook; either okfn or kfree_skb called, unless a hook
 270    returns NF_STOLEN (in which case, it's up to the hook to deal with
 271    the consequences).
 272
 273    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 274    accepted.
 275 */
 276
 277 /* RR:
 278    > I don't want nf_hook to return anything because people might forget
 279    > about async and trust the return value to mean "packet was ok".
 280
 281    AK:
 282    Just document it clearly, then you can expect some sense from kernel
 283    coders :)
 284 */
 285
 286 static inline int
 287 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 288              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 289              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 290              bool cond)
 291 {
 292         int ret;
 293
 294         if (!cond ||
 295             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
 296                 ret = okfn(net, sk, skb);
 297         return ret;
 298 }
 299
 300 static inline int
 301 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 302         struct net_device *in, struct net_device *out,
 303         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 304 {
 305         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
 306         if (ret == 1)
 307                 ret = okfn(net, sk, skb);
 308         return ret;
 309 }
 310
 311 static inline void
 312 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 313              struct list_head *head, struct net_device *in, struct net_device *out,
 314              int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 315 {
 316         struct nf_hook_entries *hook_head = NULL;
 317
 318 #ifdef CONFIG_JUMP_LABEL
 319         if (__builtin_constant_p(pf) &&
 320             __builtin_constant_p(hook) &&
 321             !static_key_false(&nf_hooks_needed[pf][hook]))
 322                 return;
 323 #endif
 324
 325         rcu_read_lock();
 326         switch (pf) {
 327         case NFPROTO_IPV4:
 328                 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
 329                 break;
 330         case NFPROTO_IPV6:
 331                 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
 332                 break;
 333         default:
 334                 WARN_ON_ONCE(1);
 335                 break;
 336         }
 337
 338         if (hook_head) {
 339                 struct nf_hook_state state;
 340
 341                 nf_hook_state_init(&state, hook, pf, in, out, sk, net, okfn);
 342
 343                 nf_hook_slow_list(head, &state, hook_head);
 344         }
 345         rcu_read_unlock();
 346 }
 347
 348 /* Call setsockopt() */
 349 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, sockptr_t opt,
 350                   unsigned int len);
 351 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 352                   int *len);
 353
 354 struct flowi;
 355 struct nf_queue_entry;
 356
 357 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
 358                     unsigned int dataoff, u_int8_t protocol,
 359                     unsigned short family);
 360
 361 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 362                             unsigned int dataoff, unsigned int len,
 363                             u_int8_t protocol, unsigned short family);
 364 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
 365              bool strict, unsigned short family);
 366 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry);
 367
 368 #include <net/flow.h>
 369
 370 struct nf_conn;
 371 enum nf_nat_manip_type;
 372 struct nlattr;
 373 enum ip_conntrack_dir;
 374
 375 struct nf_nat_hook {
 376         int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip,
 377                                const struct nlattr *attr);
 378         void (*decode_session)(struct sk_buff *skb, struct flowi *fl);
 379         unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct,
 380                                   enum nf_nat_manip_type mtype,
 381                                   enum ip_conntrack_dir dir);
 382 };
 383
 384 extern struct nf_nat_hook __rcu *nf_nat_hook;
 385
 386 static inline void
 387 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 388 {
 389 #if IS_ENABLED(CONFIG_NF_NAT)
 390         struct nf_nat_hook *nat_hook;
 391
 392         rcu_read_lock();
 393         nat_hook = rcu_dereference(nf_nat_hook);
 394         if (nat_hook && nat_hook->decode_session)
 395                 nat_hook->decode_session(skb, fl);
 396         rcu_read_unlock();
 397 #endif
 398 }
 399
 400 #else /* !CONFIG_NETFILTER */
 401 static inline int
 402 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 403              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 404              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 405              bool cond)
 406 {
 407         return okfn(net, sk, skb);
 408 }
 409
 410 static inline int
 411 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 412         struct sk_buff *skb, struct net_device *in, struct net_device *out,
 413         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 414 {
 415         return okfn(net, sk, skb);
 416 }
 417
 418 static inline void
 419 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 420              struct list_head *head, struct net_device *in, struct net_device *out,
 421              int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 422 {
 423         /* nothing to do */
 424 }
 425
 426 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 427                           struct sock *sk, struct sk_buff *skb,
 428                           struct net_device *indev, struct net_device *outdev,
 429                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 430 {
 431         return 1;
 432 }
 433 struct flowi;
 434 static inline void
 435 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 436 {
 437 }
 438 #endif /*CONFIG_NETFILTER*/
 439
 440 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 441 #include <linux/netfilter/nf_conntrack_zones_common.h>
 442
 443 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 444 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 445 struct nf_conntrack_tuple;
 446 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 447                          const struct sk_buff *skb);
 448 #else
 449 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 450 struct nf_conntrack_tuple;
 451 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 452                                        const struct sk_buff *skb)
 453 {
 454         return false;
 455 }
 456 #endif
 457
 458 struct nf_conn;
 459 enum ip_conntrack_info;
 460
 461 struct nf_ct_hook {
 462         int (*update)(struct net *net, struct sk_buff *skb);
 463         void (*destroy)(struct nf_conntrack *);
 464         bool (*get_tuple_skb)(struct nf_conntrack_tuple *,
 465                               const struct sk_buff *);
 466 };
 467 extern struct nf_ct_hook __rcu *nf_ct_hook;
 468
 469 struct nlattr;
 470
 471 struct nfnl_ct_hook {
 472         size_t (*build_size)(const struct nf_conn *ct);
 473         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 474                      enum ip_conntrack_info ctinfo,
 475                      u_int16_t ct_attr, u_int16_t ct_info_attr);
 476         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 477         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 478                              u32 portid, u32 report);
 479         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 480                            enum ip_conntrack_info ctinfo, s32 off);
 481 };
 482 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 483
 484 /**
 485  * nf_skb_duplicated - TEE target has sent a packet
 486  *
 487  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 488  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 489  *
 490  * This is used by xtables TEE target to prevent the duplicated skb from
 491  * being duplicated again.
 492  */
 493 DECLARE_PER_CPU(bool, nf_skb_duplicated);
 494
 495 #endif /*__LINUX_NETFILTER_H*/