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