LXR linux/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
  18static inline int NF_DROP_GETERR(int verdict)
  19{
  20        return -(verdict >> NF_VERDICT_QBITS);
  21}
  22
  23static 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
  32static 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
  42int netfilter_init(void);
  43
  44struct sk_buff;
  45
  46struct nf_hook_ops;
  47
  48struct sock;
  49
  50struct 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
  62static 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
  83typedef unsigned int nf_hookfn(void *priv,
  84                               struct sk_buff *skb,
  85                               const struct nf_hook_state *state);
  86
  87struct 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
 100struct 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. */
 125int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
 126void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
 127int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 128                          unsigned int n);
 129void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 130                             unsigned int n);
 131
 132int nf_register_hook(struct nf_hook_ops *reg);
 133void nf_unregister_hook(struct nf_hook_ops *reg);
 134int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 135void 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! */
 139int nf_register_sockopt(struct nf_sockopt_ops *reg);
 140void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 141
 142#ifdef HAVE_JUMP_LABEL
 143extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 144#endif
 145
 146int 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 */
 155static 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
 185static 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
 210static inline int
 211NF_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
 223static inline int
 224NF_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
 237static inline int
 238NF_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() */
 246int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 247                  unsigned int len);
 248int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 249                  int *len);
 250#ifdef CONFIG_COMPAT
 251int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 252                char __user *opt, unsigned int len);
 253int 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. */
 260int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 261
 262struct flowi;
 263struct nf_queue_entry;
 264
 265struct 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
 283extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 284static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 285{
 286        return rcu_dereference(nf_afinfo[family]);
 287}
 288
 289static inline __sum16
 290nf_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
 304static inline __sum16
 305nf_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
 321int nf_register_afinfo(const struct nf_afinfo *afinfo);
 322void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 323
 324#include <net/flow.h>
 325extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 326
 327static inline void
 328nf_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 */
 342static inline int
 343NF_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
 351static inline int
 352NF_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
 359static 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}
 366struct flowi;
 367static inline void
 368nf_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
 376extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 377void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 378extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 379#else
 380static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 381#endif
 382
 383struct nf_conn;
 384enum ip_conntrack_info;
 385struct nlattr;
 386
 387struct 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};
 400extern 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 */
 411DECLARE_PER_CPU(bool, nf_skb_duplicated);
 412
 413#endif /*__LINUX_NETFILTER_H*/
 414