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         /* User fills in from here down. */
  65         nf_hookfn               *hook;
  66         struct net_device       *dev;
  67         void                    *priv;
  68         u_int8_t                pf;
  69         unsigned int            hooknum;
  70         /* Hooks are ordered in ascending priority. */
  71         int                     priority;
  72 };
  73
  74 struct nf_hook_entry {
  75         nf_hookfn                       *hook;
  76         void                            *priv;
  77 };
  78
  79 struct nf_hook_entries {
  80         u16                             num_hook_entries;
  81         /* padding */
  82         struct nf_hook_entry            hooks[];
  83
  84         /* trailer: pointers to original orig_ops of each hook.
  85          *
  86          * This is not part of struct nf_hook_entry since its only
  87          * needed in slow path (hook register/unregister).
  88          *
  89          * const struct nf_hook_ops     *orig_ops[]
  90          */
  91 };
  92
  93 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
  94 {
  95         unsigned int n = e->num_hook_entries;
  96         const void *hook_end;
  97
  98         hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */
  99
 100         return (struct nf_hook_ops **)hook_end;
 101 }
 102
 103 static inline int
 104 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
 105                      struct nf_hook_state *state)
 106 {
 107         return entry->hook(entry->priv, skb, state);
 108 }
 109
 110 static inline void nf_hook_state_init(struct nf_hook_state *p,
 111                                       unsigned int hook,
 112                                       u_int8_t pf,
 113                                       struct net_device *indev,
 114                                       struct net_device *outdev,
 115                                       struct sock *sk,
 116                                       struct net *net,
 117                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 118 {
 119         p->hook = hook;
 120         p->pf = pf;
 121         p->in = indev;
 122         p->out = outdev;
 123         p->sk = sk;
 124         p->net = net;
 125         p->okfn = okfn;
 126 }
 127
 128
 129
 130 struct nf_sockopt_ops {
 131         struct list_head list;
 132
 133         u_int8_t pf;
 134
 135         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 136         int set_optmin;
 137         int set_optmax;
 138         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 139 #ifdef CONFIG_COMPAT
 140         int (*compat_set)(struct sock *sk, int optval,
 141                         void __user *user, unsigned int len);
 142 #endif
 143         int get_optmin;
 144         int get_optmax;
 145         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 146 #ifdef CONFIG_COMPAT
 147         int (*compat_get)(struct sock *sk, int optval,
 148                         void __user *user, int *len);
 149 #endif
 150         /* Use the module struct to lock set/get code in place */
 151         struct module *owner;
 152 };
 153
 154 /* Function to register/unregister hook points. */
 155 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 156 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 157 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 158                           unsigned int n);
 159 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 160                              unsigned int n);
 161
 162 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 163    need to check permissions yourself! */
 164 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 165 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 166
 167 #ifdef HAVE_JUMP_LABEL
 168 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 169 #endif
 170
 171 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 172                  const struct nf_hook_entries *e, unsigned int i);
 173
 174 /**
 175  *      nf_hook - call a netfilter hook
 176  *
 177  *      Returns 1 if the hook has allowed the packet to pass.  The function
 178  *      okfn must be invoked by the caller in this case.  Any other return
 179  *      value indicates the packet has been consumed by the hook.
 180  */
 181 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 182                           struct sock *sk, struct sk_buff *skb,
 183                           struct net_device *indev, struct net_device *outdev,
 184                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 185 {
 186         struct nf_hook_entries *hook_head;
 187         int ret = 1;
 188
 189 #ifdef HAVE_JUMP_LABEL
 190         if (__builtin_constant_p(pf) &&
 191             __builtin_constant_p(hook) &&
 192             !static_key_false(&nf_hooks_needed[pf][hook]))
 193                 return 1;
 194 #endif
 195
 196         rcu_read_lock();
 197         hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
 198         if (hook_head) {
 199                 struct nf_hook_state state;
 200
 201                 nf_hook_state_init(&state, hook, pf, indev, outdev,
 202                                    sk, net, okfn);
 203
 204                 ret = nf_hook_slow(skb, &state, hook_head, 0);
 205         }
 206         rcu_read_unlock();
 207
 208         return ret;
 209 }
 210
 211 /* Activate hook; either okfn or kfree_skb called, unless a hook
 212    returns NF_STOLEN (in which case, it's up to the hook to deal with
 213    the consequences).
 214
 215    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 216    accepted.
 217 */
 218
 219 /* RR:
 220    > I don't want nf_hook to return anything because people might forget
 221    > about async and trust the return value to mean "packet was ok".
 222
 223    AK:
 224    Just document it clearly, then you can expect some sense from kernel
 225    coders :)
 226 */
 227
 228 static inline int
 229 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 230              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 231              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 232              bool cond)
 233 {
 234         int ret;
 235
 236         if (!cond ||
 237             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
 238                 ret = okfn(net, sk, skb);
 239         return ret;
 240 }
 241
 242 static inline int
 243 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 244         struct net_device *in, struct net_device *out,
 245         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 246 {
 247         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
 248         if (ret == 1)
 249                 ret = okfn(net, sk, skb);
 250         return ret;
 251 }
 252
 253 /* Call setsockopt() */
 254 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 255                   unsigned int len);
 256 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 257                   int *len);
 258 #ifdef CONFIG_COMPAT
 259 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 260                 char __user *opt, unsigned int len);
 261 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 262                 char __user *opt, int *len);
 263 #endif
 264
 265 /* Call this before modifying an existing packet: ensures it is
 266    modifiable and linear to the point you care about (writable_len).
 267    Returns true or false. */
 268 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 269
 270 struct flowi;
 271 struct nf_queue_entry;
 272
 273 struct nf_afinfo {
 274         unsigned short  family;
 275         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 276                                     unsigned int dataoff, u_int8_t protocol);
 277         __sum16         (*checksum_partial)(struct sk_buff *skb,
 278                                             unsigned int hook,
 279                                             unsigned int dataoff,
 280                                             unsigned int len,
 281                                             u_int8_t protocol);
 282         int             (*route)(struct net *net, struct dst_entry **dst,
 283                                  struct flowi *fl, bool strict);
 284         void            (*saveroute)(const struct sk_buff *skb,
 285                                      struct nf_queue_entry *entry);
 286         int             (*reroute)(struct net *net, struct sk_buff *skb,
 287                                    const struct nf_queue_entry *entry);
 288         int             route_key_size;
 289 };
 290
 291 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 292 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 293 {
 294         return rcu_dereference(nf_afinfo[family]);
 295 }
 296
 297 static inline __sum16
 298 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 299             u_int8_t protocol, unsigned short family)
 300 {
 301         const struct nf_afinfo *afinfo;
 302         __sum16 csum = 0;
 303
 304         rcu_read_lock();
 305         afinfo = nf_get_afinfo(family);
 306         if (afinfo)
 307                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 308         rcu_read_unlock();
 309         return csum;
 310 }
 311
 312 static inline __sum16
 313 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 314                     unsigned int dataoff, unsigned int len,
 315                     u_int8_t protocol, unsigned short family)
 316 {
 317         const struct nf_afinfo *afinfo;
 318         __sum16 csum = 0;
 319
 320         rcu_read_lock();
 321         afinfo = nf_get_afinfo(family);
 322         if (afinfo)
 323                 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 324                                                 protocol);
 325         rcu_read_unlock();
 326         return csum;
 327 }
 328
 329 int nf_register_afinfo(const struct nf_afinfo *afinfo);
 330 void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 331
 332 #include <net/flow.h>
 333 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 334
 335 static inline void
 336 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 337 {
 338 #ifdef CONFIG_NF_NAT_NEEDED
 339         void (*decodefn)(struct sk_buff *, struct flowi *);
 340
 341         rcu_read_lock();
 342         decodefn = rcu_dereference(nf_nat_decode_session_hook);
 343         if (decodefn)
 344                 decodefn(skb, fl);
 345         rcu_read_unlock();
 346 #endif
 347 }
 348
 349 #else /* !CONFIG_NETFILTER */
 350 static inline int
 351 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 352              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 353              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 354              bool cond)
 355 {
 356         return okfn(net, sk, skb);
 357 }
 358
 359 static inline int
 360 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 361         struct sk_buff *skb, struct net_device *in, struct net_device *out,
 362         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 363 {
 364         return okfn(net, sk, skb);
 365 }
 366
 367 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 368                           struct sock *sk, struct sk_buff *skb,
 369                           struct net_device *indev, struct net_device *outdev,
 370                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 371 {
 372         return 1;
 373 }
 374 struct flowi;
 375 static inline void
 376 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 377 {
 378 }
 379 #endif /*CONFIG_NETFILTER*/
 380
 381 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 382 #include <linux/netfilter/nf_conntrack_zones_common.h>
 383
 384 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 385 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 386 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 387 #else
 388 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 389 #endif
 390
 391 struct nf_conn;
 392 enum ip_conntrack_info;
 393 struct nlattr;
 394
 395 struct nfnl_ct_hook {
 396         struct nf_conn *(*get_ct)(const struct sk_buff *skb,
 397                                   enum ip_conntrack_info *ctinfo);
 398         size_t (*build_size)(const struct nf_conn *ct);
 399         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 400                      enum ip_conntrack_info ctinfo,
 401                      u_int16_t ct_attr, u_int16_t ct_info_attr);
 402         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 403         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 404                              u32 portid, u32 report);
 405         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 406                            enum ip_conntrack_info ctinfo, s32 off);
 407 };
 408 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 409
 410 /**
 411  * nf_skb_duplicated - TEE target has sent a packet
 412  *
 413  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 414  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 415  *
 416  * This is used by xtables TEE target to prevent the duplicated skb from
 417  * being duplicated again.
 418  */
 419 DECLARE_PER_CPU(bool, nf_skb_duplicated);
 420
 421 #endif /*__LINUX_NETFILTER_H*/