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         struct nf_hook_entry __rcu *hook_entries;
  58         int (*okfn)(struct net *, struct sock *, struct sk_buff *);
  59 };
  60
  61 typedef unsigned int nf_hookfn(void *priv,
  62                                struct sk_buff *skb,
  63                                const struct nf_hook_state *state);
  64 struct nf_hook_ops {
  65         struct list_head        list;
  66
  67         /* User fills in from here down. */
  68         nf_hookfn               *hook;
  69         struct net_device       *dev;
  70         void                    *priv;
  71         u_int8_t                pf;
  72         unsigned int            hooknum;
  73         /* Hooks are ordered in ascending priority. */
  74         int                     priority;
  75 };
  76
  77 struct nf_hook_entry {
  78         struct nf_hook_entry __rcu      *next;
  79         struct nf_hook_ops              ops;
  80         const struct nf_hook_ops        *orig_ops;
  81 };
  82
  83 static inline void nf_hook_state_init(struct nf_hook_state *p,
  84                                       struct nf_hook_entry *hook_entry,
  85                                       unsigned int hook,
  86                                       u_int8_t pf,
  87                                       struct net_device *indev,
  88                                       struct net_device *outdev,
  89                                       struct sock *sk,
  90                                       struct net *net,
  91                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
  92 {
  93         p->hook = hook;
  94         p->pf = pf;
  95         p->in = indev;
  96         p->out = outdev;
  97         p->sk = sk;
  98         p->net = net;
  99         RCU_INIT_POINTER(p->hook_entries, hook_entry);
 100         p->okfn = okfn;
 101 }
 102
 103
 104
 105 struct nf_sockopt_ops {
 106         struct list_head list;
 107
 108         u_int8_t pf;
 109
 110         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 111         int set_optmin;
 112         int set_optmax;
 113         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 114 #ifdef CONFIG_COMPAT
 115         int (*compat_set)(struct sock *sk, int optval,
 116                         void __user *user, unsigned int len);
 117 #endif
 118         int get_optmin;
 119         int get_optmax;
 120         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 121 #ifdef CONFIG_COMPAT
 122         int (*compat_get)(struct sock *sk, int optval,
 123                         void __user *user, int *len);
 124 #endif
 125         /* Use the module struct to lock set/get code in place */
 126         struct module *owner;
 127 };
 128
 129 /* Function to register/unregister hook points. */
 130 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 131 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 132 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 133                           unsigned int n);
 134 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 135                              unsigned int n);
 136
 137 int nf_register_hook(struct nf_hook_ops *reg);
 138 void nf_unregister_hook(struct nf_hook_ops *reg);
 139 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 140 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 141 int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 142 void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 143
 144 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 145    need to check permissions yourself! */
 146 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 147 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 148
 149 #ifdef HAVE_JUMP_LABEL
 150 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 151 #endif
 152
 153 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state);
 154
 155 /**
 156  *      nf_hook - call a netfilter hook
 157  *
 158  *      Returns 1 if the hook has allowed the packet to pass.  The function
 159  *      okfn must be invoked by the caller in this case.  Any other return
 160  *      value indicates the packet has been consumed by the hook.
 161  */
 162 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 163                           struct sock *sk, struct sk_buff *skb,
 164                           struct net_device *indev, struct net_device *outdev,
 165                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 166 {
 167         struct nf_hook_entry *hook_head;
 168         int ret = 1;
 169
 170 #ifdef HAVE_JUMP_LABEL
 171         if (__builtin_constant_p(pf) &&
 172             __builtin_constant_p(hook) &&
 173             !static_key_false(&nf_hooks_needed[pf][hook]))
 174                 return 1;
 175 #endif
 176
 177         rcu_read_lock();
 178         hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
 179         if (hook_head) {
 180                 struct nf_hook_state state;
 181
 182                 nf_hook_state_init(&state, hook_head, hook, pf, indev, outdev,
 183                                    sk, net, okfn);
 184
 185                 ret = nf_hook_slow(skb, &state);
 186         }
 187         rcu_read_unlock();
 188
 189         return ret;
 190 }
 191
 192 /* Activate hook; either okfn or kfree_skb called, unless a hook
 193    returns NF_STOLEN (in which case, it's up to the hook to deal with
 194    the consequences).
 195
 196    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 197    accepted.
 198 */
 199
 200 /* RR:
 201    > I don't want nf_hook to return anything because people might forget
 202    > about async and trust the return value to mean "packet was ok".
 203
 204    AK:
 205    Just document it clearly, then you can expect some sense from kernel
 206    coders :)
 207 */
 208
 209 static inline int
 210 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 211              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 212              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 213              bool cond)
 214 {
 215         int ret;
 216
 217         if (!cond ||
 218             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
 219                 ret = okfn(net, sk, skb);
 220         return ret;
 221 }
 222
 223 static inline int
 224 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 225         struct net_device *in, struct net_device *out,
 226         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 227 {
 228         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
 229         if (ret == 1)
 230                 ret = okfn(net, sk, skb);
 231         return ret;
 232 }
 233
 234 /* Call setsockopt() */
 235 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 236                   unsigned int len);
 237 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 238                   int *len);
 239 #ifdef CONFIG_COMPAT
 240 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 241                 char __user *opt, unsigned int len);
 242 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 243                 char __user *opt, int *len);
 244 #endif
 245
 246 /* Call this before modifying an existing packet: ensures it is
 247    modifiable and linear to the point you care about (writable_len).
 248    Returns true or false. */
 249 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 250
 251 struct flowi;
 252 struct nf_queue_entry;
 253
 254 struct nf_afinfo {
 255         unsigned short  family;
 256         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 257                                     unsigned int dataoff, u_int8_t protocol);
 258         __sum16         (*checksum_partial)(struct sk_buff *skb,
 259                                             unsigned int hook,
 260                                             unsigned int dataoff,
 261                                             unsigned int len,
 262                                             u_int8_t protocol);
 263         int             (*route)(struct net *net, struct dst_entry **dst,
 264                                  struct flowi *fl, bool strict);
 265         void            (*saveroute)(const struct sk_buff *skb,
 266                                      struct nf_queue_entry *entry);
 267         int             (*reroute)(struct net *net, struct sk_buff *skb,
 268                                    const struct nf_queue_entry *entry);
 269         int             route_key_size;
 270 };
 271
 272 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 273 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 274 {
 275         return rcu_dereference(nf_afinfo[family]);
 276 }
 277
 278 static inline __sum16
 279 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 280             u_int8_t protocol, unsigned short family)
 281 {
 282         const struct nf_afinfo *afinfo;
 283         __sum16 csum = 0;
 284
 285         rcu_read_lock();
 286         afinfo = nf_get_afinfo(family);
 287         if (afinfo)
 288                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 289         rcu_read_unlock();
 290         return csum;
 291 }
 292
 293 static inline __sum16
 294 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 295                     unsigned int dataoff, unsigned int len,
 296                     u_int8_t protocol, unsigned short family)
 297 {
 298         const struct nf_afinfo *afinfo;
 299         __sum16 csum = 0;
 300
 301         rcu_read_lock();
 302         afinfo = nf_get_afinfo(family);
 303         if (afinfo)
 304                 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 305                                                 protocol);
 306         rcu_read_unlock();
 307         return csum;
 308 }
 309
 310 int nf_register_afinfo(const struct nf_afinfo *afinfo);
 311 void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 312
 313 #include <net/flow.h>
 314 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 315
 316 static inline void
 317 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 318 {
 319 #ifdef CONFIG_NF_NAT_NEEDED
 320         void (*decodefn)(struct sk_buff *, struct flowi *);
 321
 322         rcu_read_lock();
 323         decodefn = rcu_dereference(nf_nat_decode_session_hook);
 324         if (decodefn)
 325                 decodefn(skb, fl);
 326         rcu_read_unlock();
 327 #endif
 328 }
 329
 330 #else /* !CONFIG_NETFILTER */
 331 static inline int
 332 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 333              struct sk_buff *skb, struct net_device *in, struct net_device *out,
 334              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 335              bool cond)
 336 {
 337         return okfn(net, sk, skb);
 338 }
 339
 340 static inline int
 341 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 342         struct sk_buff *skb, struct net_device *in, struct net_device *out,
 343         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 344 {
 345         return okfn(net, sk, skb);
 346 }
 347
 348 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
 349                           struct sock *sk, struct sk_buff *skb,
 350                           struct net_device *indev, struct net_device *outdev,
 351                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
 352 {
 353         return 1;
 354 }
 355 struct flowi;
 356 static inline void
 357 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 358 {
 359 }
 360 #endif /*CONFIG_NETFILTER*/
 361
 362 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 363 #include <linux/netfilter/nf_conntrack_zones_common.h>
 364
 365 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 366 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 367 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 368 #else
 369 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 370 #endif
 371
 372 struct nf_conn;
 373 enum ip_conntrack_info;
 374 struct nlattr;
 375
 376 struct nfnl_ct_hook {
 377         struct nf_conn *(*get_ct)(const struct sk_buff *skb,
 378                                   enum ip_conntrack_info *ctinfo);
 379         size_t (*build_size)(const struct nf_conn *ct);
 380         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 381                      enum ip_conntrack_info ctinfo,
 382                      u_int16_t ct_attr, u_int16_t ct_info_attr);
 383         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 384         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 385                              u32 portid, u32 report);
 386         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 387                            enum ip_conntrack_info ctinfo, s32 off);
 388 };
 389 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 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*/