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 #endif
 145
 146 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state);
 147
 148 /**
 149  *      nf_hook_thresh - call a netfilter hook
 150  *
 151  *      Returns 1 if the hook has allowed the packet to pass.  The function
 152  *      okfn must be invoked by the caller in this case.  Any other return
 153  *      value indicates the packet has been consumed by the hook.
 154  */
 155 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 156                                  struct net *net,
 157                                  struct sock *sk,
 158                                  struct sk_buff *skb,
 159                                  struct net_device *indev,
 160                                  struct net_device *outdev,
 161                                  int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 162                                  int thresh)
 163 {
 164         struct list_head *hook_list;
 165
 166 #ifdef HAVE_JUMP_LABEL
 167         if (__builtin_constant_p(pf) &&
 168             __builtin_constant_p(hook) &&
 169             !static_key_false(&nf_hooks_needed[pf][hook]))
 170                 return 1;
 171 #endif
 172
 173         hook_list = &net->nf.hooks[pf][hook];
 174
 175         if (!list_empty(hook_list)) {
 176                 struct nf_hook_state state;
 177
 178                 nf_hook_state_init(&state, hook_list, hook, thresh,
 179                                    pf, indev, outdev, sk, net, okfn);
 180                 return nf_hook_slow(skb, &state);
 181         }
 182         return 1;
 183 }
 184
 185 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 186                           struct sock *sk, struct sk_buff *skb,
 187                           struct net_device *indev, struct net_device *outdev,
 188                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 189 {
 190         return nf_hook_thresh(pf, hook, net, sk, skb, indev, outdev, okfn, INT_MIN);
 191 }
 192
 193 /* Activate hook; either okfn or kfree_skb called, unless a hook
 194    returns NF_STOLEN (in which case, it's up to the hook to deal with
 195    the consequences).
 196
 197    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 198    accepted.
 199 */
 200
 201 /* RR:
 202    > I don't want nf_hook to return anything because people might forget
 203    > about async and trust the return value to mean "packet was ok".
 204
 205    AK:
 206    Just document it clearly, then you can expect some sense from kernel
 207    coders :)
 208 */
 209
 210 static inline int
 211 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 212                struct sk_buff *skb, struct net_device *in,
 213                struct net_device *out,
 214                int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 215                int thresh)
 216 {
 217         int ret = nf_hook_thresh(pf, hook, net, sk, skb, in, out, okfn, thresh);
 218         if (ret == 1)
 219                 ret = okfn(net, sk, skb);
 220         return ret;
 221 }
 222
 223 static inline int
 224 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 225              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 226              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 227              bool cond)
 228 {
 229         int ret;
 230
 231         if (!cond ||
 232             ((ret = nf_hook_thresh(pf, hook, net, sk, skb, in, out, okfn, INT_MIN)) == 1))
 233                 ret = okfn(net, sk, skb);
 234         return ret;
 235 }
 236
 237 static inline int
 238 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 239         struct net_device *in, struct net_device *out,
 240         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 241 {
 242         return NF_HOOK_THRESH(pf, hook, net, sk, skb, in, out, okfn, INT_MIN);
 243 }
 244
 245 /* Call setsockopt() */
 246 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 247                   unsigned int len);
 248 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 249                   int *len);
 250 #ifdef CONFIG_COMPAT
 251 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 252                 char __user *opt, unsigned int len);
 253 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 254                 char __user *opt, int *len);
 255 #endif
 256
 257 /* Call this before modifying an existing packet: ensures it is
 258    modifiable and linear to the point you care about (writable_len).
 259    Returns true or false. */
 260 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 261
 262 struct flowi;
 263 struct nf_queue_entry;
 264
 265 struct nf_afinfo {
 266         unsigned short  family;
 267         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 268                                     unsigned int dataoff, u_int8_t protocol);
 269         __sum16         (*checksum_partial)(struct sk_buff *skb,
 270                                             unsigned int hook,
 271                                             unsigned int dataoff,
 272                                             unsigned int len,
 273                                             u_int8_t protocol);
 274         int             (*route)(struct net *net, struct dst_entry **dst,
 275                                  struct flowi *fl, bool strict);
 276         void            (*saveroute)(const struct sk_buff *skb,
 277                                      struct nf_queue_entry *entry);
 278         int             (*reroute)(struct net *net, struct sk_buff *skb,
 279                                    const struct nf_queue_entry *entry);
 280         int             route_key_size;
 281 };
 282
 283 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 284 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 285 {
 286         return rcu_dereference(nf_afinfo[family]);
 287 }
 288
 289 static inline __sum16
 290 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 291             u_int8_t protocol, unsigned short family)
 292 {
 293         const struct nf_afinfo *afinfo;
 294         __sum16 csum = 0;
 295
 296         rcu_read_lock();
 297         afinfo = nf_get_afinfo(family);
 298         if (afinfo)
 299                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 300         rcu_read_unlock();
 301         return csum;
 302 }
 303
 304 static inline __sum16
 305 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 306                     unsigned int dataoff, unsigned int len,
 307                     u_int8_t protocol, unsigned short family)
 308 {
 309         const struct nf_afinfo *afinfo;
 310         __sum16 csum = 0;
 311
 312         rcu_read_lock();
 313         afinfo = nf_get_afinfo(family);
 314         if (afinfo)
 315                 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 316                                                 protocol);
 317         rcu_read_unlock();
 318         return csum;
 319 }
 320
 321 int nf_register_afinfo(const struct nf_afinfo *afinfo);
 322 void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 323
 324 #include <net/flow.h>
 325 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 326
 327 static inline void
 328 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 329 {
 330 #ifdef CONFIG_NF_NAT_NEEDED
 331         void (*decodefn)(struct sk_buff *, struct flowi *);
 332
 333         rcu_read_lock();
 334         decodefn = rcu_dereference(nf_nat_decode_session_hook);
 335         if (decodefn)
 336                 decodefn(skb, fl);
 337         rcu_read_unlock();
 338 #endif
 339 }
 340
 341 #else /* !CONFIG_NETFILTER */
 342 static inline int
 343 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 344              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 345              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 346              bool cond)
 347 {
 348         return okfn(net, sk, skb);
 349 }
 350
 351 static inline int
 352 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 353         struct sk_buff *skb, struct net_device *in, struct net_device *out,
 354         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 355 {
 356         return okfn(net, sk, skb);
 357 }
 358
 359 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 360                           struct sock *sk, struct sk_buff *skb,
 361                           struct net_device *indev, struct net_device *outdev,
 362                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 363 {
 364         return 1;
 365 }
 366 struct flowi;
 367 static inline void
 368 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 369 {
 370 }
 371 #endif /*CONFIG_NETFILTER*/
 372
 373 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 374 #include <linux/netfilter/nf_conntrack_zones_common.h>
 375
 376 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 377 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 378 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 379 #else
 380 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 381 #endif
 382
 383 struct nf_conn;
 384 enum ip_conntrack_info;
 385 struct nlattr;
 386
 387 struct nfnl_ct_hook {
 388         struct nf_conn *(*get_ct)(const struct sk_buff *skb,
 389                                   enum ip_conntrack_info *ctinfo);
 390         size_t (*build_size)(const struct nf_conn *ct);
 391         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 392                      enum ip_conntrack_info ctinfo,
 393                      u_int16_t ct_attr, u_int16_t ct_info_attr);
 394         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 395         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 396                              u32 portid, u32 report);
 397         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 398                            enum ip_conntrack_info ctinfo, s32 off);
 399 };
 400 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 401
 402 /**
 403  * nf_skb_duplicated - TEE target has sent a packet
 404  *
 405  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 406  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 407  *
 408  * This is used by xtables TEE target to prevent the duplicated skb from
 409  * being duplicated again.
 410  */
 411 DECLARE_PER_CPU(bool, nf_skb_duplicated);
 412
 413 #endif /*__LINUX_NETFILTER_H*/