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         struct module           *owner;
  94         void                    *priv;
  95         u_int8_t                pf;
  96         unsigned int            hooknum;
  97         /* Hooks are ordered in ascending priority. */
  98         int                     priority;
  99 };
 100
 101 struct nf_sockopt_ops {
 102         struct list_head list;
 103
 104         u_int8_t pf;
 105
 106         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 107         int set_optmin;
 108         int set_optmax;
 109         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 110 #ifdef CONFIG_COMPAT
 111         int (*compat_set)(struct sock *sk, int optval,
 112                         void __user *user, unsigned int len);
 113 #endif
 114         int get_optmin;
 115         int get_optmax;
 116         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 117 #ifdef CONFIG_COMPAT
 118         int (*compat_get)(struct sock *sk, int optval,
 119                         void __user *user, int *len);
 120 #endif
 121         /* Use the module struct to lock set/get code in place */
 122         struct module *owner;
 123 };
 124
 125 /* Function to register/unregister hook points. */
 126 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 127 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 128 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 129                           unsigned int n);
 130 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 131                              unsigned int n);
 132
 133 int nf_register_hook(struct nf_hook_ops *reg);
 134 void nf_unregister_hook(struct nf_hook_ops *reg);
 135 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 136 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 137
 138 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 139    need to check permissions yourself! */
 140 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 141 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 142
 143 #ifdef HAVE_JUMP_LABEL
 144 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 145
 146 static inline bool nf_hook_list_active(struct list_head *hook_list,
 147                                        u_int8_t pf, unsigned int hook)
 148 {
 149         if (__builtin_constant_p(pf) &&
 150             __builtin_constant_p(hook))
 151                 return static_key_false(&nf_hooks_needed[pf][hook]);
 152
 153         return !list_empty(hook_list);
 154 }
 155 #else
 156 static inline bool nf_hook_list_active(struct list_head *hook_list,
 157                                        u_int8_t pf, unsigned int hook)
 158 {
 159         return !list_empty(hook_list);
 160 }
 161 #endif
 162
 163 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state);
 164
 165 /**
 166  *      nf_hook_thresh - call a netfilter hook
 167  *
 168  *      Returns 1 if the hook has allowed the packet to pass.  The function
 169  *      okfn must be invoked by the caller in this case.  Any other return
 170  *      value indicates the packet has been consumed by the hook.
 171  */
 172 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 173                                  struct net *net,
 174                                  struct sock *sk,
 175                                  struct sk_buff *skb,
 176                                  struct net_device *indev,
 177                                  struct net_device *outdev,
 178                                  int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 179                                  int thresh)
 180 {
 181         struct list_head *hook_list = &net->nf.hooks[pf][hook];
 182
 183         if (nf_hook_list_active(hook_list, pf, hook)) {
 184                 struct nf_hook_state state;
 185
 186                 nf_hook_state_init(&state, hook_list, hook, thresh,
 187                                    pf, indev, outdev, sk, net, okfn);
 188                 return nf_hook_slow(skb, &state);
 189         }
 190         return 1;
 191 }
 192
 193 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 194                           struct sock *sk, struct sk_buff *skb,
 195                           struct net_device *indev, struct net_device *outdev,
 196                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 197 {
 198         return nf_hook_thresh(pf, hook, net, sk, skb, indev, outdev, okfn, INT_MIN);
 199 }
 200
 201 /* Activate hook; either okfn or kfree_skb called, unless a hook
 202    returns NF_STOLEN (in which case, it's up to the hook to deal with
 203    the consequences).
 204
 205    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 206    accepted.
 207 */
 208
 209 /* RR:
 210    > I don't want nf_hook to return anything because people might forget
 211    > about async and trust the return value to mean "packet was ok".
 212
 213    AK:
 214    Just document it clearly, then you can expect some sense from kernel
 215    coders :)
 216 */
 217
 218 static inline int
 219 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 220                struct sk_buff *skb, struct net_device *in,
 221                struct net_device *out,
 222                int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 223                int thresh)
 224 {
 225         int ret = nf_hook_thresh(pf, hook, net, sk, skb, in, out, okfn, thresh);
 226         if (ret == 1)
 227                 ret = okfn(net, sk, skb);
 228         return ret;
 229 }
 230
 231 static inline int
 232 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 233              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 234              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 235              bool cond)
 236 {
 237         int ret;
 238
 239         if (!cond ||
 240             ((ret = nf_hook_thresh(pf, hook, net, sk, skb, in, out, okfn, INT_MIN)) == 1))
 241                 ret = okfn(net, sk, skb);
 242         return ret;
 243 }
 244
 245 static inline int
 246 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 247         struct net_device *in, struct net_device *out,
 248         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 249 {
 250         return NF_HOOK_THRESH(pf, hook, net, sk, skb, in, out, okfn, INT_MIN);
 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 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 #define NF_HOOK(pf, hook, net, sk, skb, indev, outdev, okfn) (okfn)(net, sk, skb)
 351 #define NF_HOOK_COND(pf, hook, net, sk, skb, indev, outdev, okfn, cond) (okfn)(net, sk, skb)
 352 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 353                           struct sock *sk, struct sk_buff *skb,
 354                           struct net_device *indev, struct net_device *outdev,
 355                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 356 {
 357         return 1;
 358 }
 359 struct flowi;
 360 static inline void
 361 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 362 {
 363 }
 364 #endif /*CONFIG_NETFILTER*/
 365
 366 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 367 #include <linux/netfilter/nf_conntrack_zones_common.h>
 368
 369 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 370 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 371 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 372
 373 struct nf_conn;
 374 enum ip_conntrack_info;
 375 struct nlattr;
 376
 377 struct nfq_ct_hook {
 378         size_t (*build_size)(const struct nf_conn *ct);
 379         int (*build)(struct sk_buff *skb, struct nf_conn *ct);
 380         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 381         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 382                              u32 portid, u32 report);
 383         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 384                            enum ip_conntrack_info ctinfo, s32 off);
 385 };
 386 extern struct nfq_ct_hook __rcu *nfq_ct_hook;
 387 #else
 388 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 389 #endif
 390
 391 /**
 392  * nf_skb_duplicated - TEE target has sent a packet
 393  *
 394  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
 395  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
 396  *
 397  * This is used by xtables TEE target to prevent the duplicated skb from
 398  * being duplicated again.
 399  */
 400 DECLARE_PER_CPU(bool, nf_skb_duplicated);
 401
 402 #endif /*__LINUX_NETFILTER_H*/