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         struct nf_hook_entry __rcu      *next;
  76         nf_hookfn                       *hook;
  77         void                            *priv;
  78         const struct nf_hook_ops        *orig_ops;
  79 };
  80
  81 static inline void
  82 nf_hook_entry_init(struct nf_hook_entry *entry, const struct nf_hook_ops *ops)
  83 {
  84         entry->next = NULL;
  85         entry->hook = ops->hook;
  86         entry->priv = ops->priv;
  87         entry->orig_ops = ops;
  88 }
  89
  90 static inline int
  91 nf_hook_entry_priority(const struct nf_hook_entry *entry)
  92 {
  93         return entry->orig_ops->priority;
  94 }
  95
  96 static inline int
  97 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
  98                      struct nf_hook_state *state)
  99 {
 100         return entry->hook(entry->priv, skb, state);
 101 }
 102
 103 static inline const struct nf_hook_ops *
 104 nf_hook_entry_ops(const struct nf_hook_entry *entry)
 105 {
 106         return entry->orig_ops;
 107 }
 108
 109 static inline void nf_hook_state_init(struct nf_hook_state *p,
 110                                       unsigned int hook,
 111                                       u_int8_t pf,
 112                                       struct net_device *indev,
 113                                       struct net_device *outdev,
 114                                       struct sock *sk,
 115                                       struct net *net,
 116                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 117 {
 118         p->hook = hook;
 119         p->pf = pf;
 120         p->in = indev;
 121         p->out = outdev;
 122         p->sk = sk;
 123         p->net = net;
 124         p->okfn = okfn;
 125 }
 126
 127
 128
 129 struct nf_sockopt_ops {
 130         struct list_head list;
 131
 132         u_int8_t pf;
 133
 134         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 135         int set_optmin;
 136         int set_optmax;
 137         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 138 #ifdef CONFIG_COMPAT
 139         int (*compat_set)(struct sock *sk, int optval,
 140                         void __user *user, unsigned int len);
 141 #endif
 142         int get_optmin;
 143         int get_optmax;
 144         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 145 #ifdef CONFIG_COMPAT
 146         int (*compat_get)(struct sock *sk, int optval,
 147                         void __user *user, int *len);
 148 #endif
 149         /* Use the module struct to lock set/get code in place */
 150         struct module *owner;
 151 };
 152
 153 /* Function to register/unregister hook points. */
 154 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 155 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 156 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 157                           unsigned int n);
 158 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 159                              unsigned int n);
 160
 161 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 162    need to check permissions yourself! */
 163 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 164 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 165
 166 #ifdef HAVE_JUMP_LABEL
 167 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 168 #endif
 169
 170 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 171                  struct nf_hook_entry *entry);
 172
 173 /**
 174  *      nf_hook - call a netfilter hook
 175  *
 176  *      Returns 1 if the hook has allowed the packet to pass.  The function
 177  *      okfn must be invoked by the caller in this case.  Any other return
 178  *      value indicates the packet has been consumed by the hook.
 179  */
 180 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 181                           struct sock *sk, struct sk_buff *skb,
 182                           struct net_device *indev, struct net_device *outdev,
 183                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 184 {
 185         struct nf_hook_entry *hook_head;
 186         int ret = 1;
 187
 188 #ifdef HAVE_JUMP_LABEL
 189         if (__builtin_constant_p(pf) &&
 190             __builtin_constant_p(hook) &&
 191             !static_key_false(&nf_hooks_needed[pf][hook]))
 192                 return 1;
 193 #endif
 194
 195         rcu_read_lock();
 196         hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
 197         if (hook_head) {
 198                 struct nf_hook_state state;
 199
 200                 nf_hook_state_init(&state, hook, pf, indev, outdev,
 201                                    sk, net, okfn);
 202
 203                 ret = nf_hook_slow(skb, &state, hook_head);
 204         }
 205         rcu_read_unlock();
 206
 207         return ret;
 208 }
 209
 210 /* Activate hook; either okfn or kfree_skb called, unless a hook
 211    returns NF_STOLEN (in which case, it's up to the hook to deal with
 212    the consequences).
 213
 214    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 215    accepted.
 216 */
 217
 218 /* RR:
 219    > I don't want nf_hook to return anything because people might forget
 220    > about async and trust the return value to mean "packet was ok".
 221
 222    AK:
 223    Just document it clearly, then you can expect some sense from kernel
 224    coders :)
 225 */
 226
 227 static inline int
 228 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 229              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 230              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 231              bool cond)
 232 {
 233         int ret;
 234
 235         if (!cond ||
 236             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
 237                 ret = okfn(net, sk, skb);
 238         return ret;
 239 }
 240
 241 static inline int
 242 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 243         struct net_device *in, struct net_device *out,
 244         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 245 {
 246         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
 247         if (ret == 1)
 248                 ret = okfn(net, sk, skb);
 249         return ret;
 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*/