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 <uapi/linux/netfilter.h>
  13#ifdef CONFIG_NETFILTER
  14static inline int NF_DROP_GETERR(int verdict)
  15{
  16        return -(verdict >> NF_VERDICT_QBITS);
  17}
  18
  19static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  20                                   const union nf_inet_addr *a2)
  21{
  22        return a1->all[0] == a2->all[0] &&
  23               a1->all[1] == a2->all[1] &&
  24               a1->all[2] == a2->all[2] &&
  25               a1->all[3] == a2->all[3];
  26}
  27
  28static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
  29                                     union nf_inet_addr *result,
  30                                     const union nf_inet_addr *mask)
  31{
  32        result->all[0] = a1->all[0] & mask->all[0];
  33        result->all[1] = a1->all[1] & mask->all[1];
  34        result->all[2] = a1->all[2] & mask->all[2];
  35        result->all[3] = a1->all[3] & mask->all[3];
  36}
  37
  38int netfilter_init(void);
  39
  40/* Largest hook number + 1 */
  41#define NF_MAX_HOOKS 8
  42
  43struct sk_buff;
  44
  45struct nf_hook_ops;
  46typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops,
  47                               struct sk_buff *skb,
  48                               const struct net_device *in,
  49                               const struct net_device *out,
  50                               int (*okfn)(struct sk_buff *));
  51
  52struct nf_hook_ops {
  53        struct list_head list;
  54
  55        /* User fills in from here down. */
  56        nf_hookfn       *hook;
  57        struct module   *owner;
  58        void            *priv;
  59        u_int8_t        pf;
  60        unsigned int    hooknum;
  61        /* Hooks are ordered in ascending priority. */
  62        int             priority;
  63};
  64
  65struct nf_sockopt_ops {
  66        struct list_head list;
  67
  68        u_int8_t pf;
  69
  70        /* Non-inclusive ranges: use 0/0/NULL to never get called. */
  71        int set_optmin;
  72        int set_optmax;
  73        int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
  74#ifdef CONFIG_COMPAT
  75        int (*compat_set)(struct sock *sk, int optval,
  76                        void __user *user, unsigned int len);
  77#endif
  78        int get_optmin;
  79        int get_optmax;
  80        int (*get)(struct sock *sk, int optval, void __user *user, int *len);
  81#ifdef CONFIG_COMPAT
  82        int (*compat_get)(struct sock *sk, int optval,
  83                        void __user *user, int *len);
  84#endif
  85        /* Use the module struct to lock set/get code in place */
  86        struct module *owner;
  87};
  88
  89/* Function to register/unregister hook points. */
  90int nf_register_hook(struct nf_hook_ops *reg);
  91void nf_unregister_hook(struct nf_hook_ops *reg);
  92int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
  93void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
  94
  95/* Functions to register get/setsockopt ranges (non-inclusive).  You
  96   need to check permissions yourself! */
  97int nf_register_sockopt(struct nf_sockopt_ops *reg);
  98void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
  99
 100extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 101
 102#if defined(CONFIG_JUMP_LABEL)
 103#include <linux/static_key.h>
 104extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 105static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
 106{
 107        if (__builtin_constant_p(pf) &&
 108            __builtin_constant_p(hook))
 109                return static_key_false(&nf_hooks_needed[pf][hook]);
 110
 111        return !list_empty(&nf_hooks[pf][hook]);
 112}
 113#else
 114static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
 115{
 116        return !list_empty(&nf_hooks[pf][hook]);
 117}
 118#endif
 119
 120int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 121                 struct net_device *indev, struct net_device *outdev,
 122                 int (*okfn)(struct sk_buff *), int thresh);
 123
 124/**
 125 *      nf_hook_thresh - call a netfilter hook
 126 *      
 127 *      Returns 1 if the hook has allowed the packet to pass.  The function
 128 *      okfn must be invoked by the caller in this case.  Any other return
 129 *      value indicates the packet has been consumed by the hook.
 130 */
 131static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 132                                 struct sk_buff *skb,
 133                                 struct net_device *indev,
 134                                 struct net_device *outdev,
 135                                 int (*okfn)(struct sk_buff *), int thresh)
 136{
 137        if (nf_hooks_active(pf, hook))
 138                return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
 139        return 1;
 140}
 141
 142static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 143                          struct net_device *indev, struct net_device *outdev,
 144                          int (*okfn)(struct sk_buff *))
 145{
 146        return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
 147}
 148                   
 149/* Activate hook; either okfn or kfree_skb called, unless a hook
 150   returns NF_STOLEN (in which case, it's up to the hook to deal with
 151   the consequences).
 152
 153   Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 154   accepted.
 155*/
 156
 157/* RR:
 158   > I don't want nf_hook to return anything because people might forget
 159   > about async and trust the return value to mean "packet was ok".
 160
 161   AK:
 162   Just document it clearly, then you can expect some sense from kernel
 163   coders :)
 164*/
 165
 166static inline int
 167NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 168               struct net_device *in, struct net_device *out,
 169               int (*okfn)(struct sk_buff *), int thresh)
 170{
 171        int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
 172        if (ret == 1)
 173                ret = okfn(skb);
 174        return ret;
 175}
 176
 177static inline int
 178NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 179             struct net_device *in, struct net_device *out,
 180             int (*okfn)(struct sk_buff *), bool cond)
 181{
 182        int ret;
 183
 184        if (!cond ||
 185            ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
 186                ret = okfn(skb);
 187        return ret;
 188}
 189
 190static inline int
 191NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 192        struct net_device *in, struct net_device *out,
 193        int (*okfn)(struct sk_buff *))
 194{
 195        return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
 196}
 197
 198/* Call setsockopt() */
 199int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 200                  unsigned int len);
 201int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 202                  int *len);
 203#ifdef CONFIG_COMPAT
 204int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 205                char __user *opt, unsigned int len);
 206int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 207                char __user *opt, int *len);
 208#endif
 209
 210/* Call this before modifying an existing packet: ensures it is
 211   modifiable and linear to the point you care about (writable_len).
 212   Returns true or false. */
 213int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 214
 215struct flowi;
 216struct nf_queue_entry;
 217
 218struct nf_afinfo {
 219        unsigned short  family;
 220        __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 221                                    unsigned int dataoff, u_int8_t protocol);
 222        __sum16         (*checksum_partial)(struct sk_buff *skb,
 223                                            unsigned int hook,
 224                                            unsigned int dataoff,
 225                                            unsigned int len,
 226                                            u_int8_t protocol);
 227        int             (*route)(struct net *net, struct dst_entry **dst,
 228                                 struct flowi *fl, bool strict);
 229        void            (*saveroute)(const struct sk_buff *skb,
 230                                     struct nf_queue_entry *entry);
 231        int             (*reroute)(struct sk_buff *skb,
 232                                   const struct nf_queue_entry *entry);
 233        int             route_key_size;
 234};
 235
 236extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 237static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 238{
 239        return rcu_dereference(nf_afinfo[family]);
 240}
 241
 242static inline __sum16
 243nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 244            u_int8_t protocol, unsigned short family)
 245{
 246        const struct nf_afinfo *afinfo;
 247        __sum16 csum = 0;
 248
 249        rcu_read_lock();
 250        afinfo = nf_get_afinfo(family);
 251        if (afinfo)
 252                csum = afinfo->checksum(skb, hook, dataoff, protocol);
 253        rcu_read_unlock();
 254        return csum;
 255}
 256
 257static inline __sum16
 258nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 259                    unsigned int dataoff, unsigned int len,
 260                    u_int8_t protocol, unsigned short family)
 261{
 262        const struct nf_afinfo *afinfo;
 263        __sum16 csum = 0;
 264
 265        rcu_read_lock();
 266        afinfo = nf_get_afinfo(family);
 267        if (afinfo)
 268                csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 269                                                protocol);
 270        rcu_read_unlock();
 271        return csum;
 272}
 273
 274int nf_register_afinfo(const struct nf_afinfo *afinfo);
 275void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 276
 277#include <net/flow.h>
 278extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 279
 280static inline void
 281nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 282{
 283#ifdef CONFIG_NF_NAT_NEEDED
 284        void (*decodefn)(struct sk_buff *, struct flowi *);
 285
 286        rcu_read_lock();
 287        decodefn = rcu_dereference(nf_nat_decode_session_hook);
 288        if (decodefn)
 289                decodefn(skb, fl);
 290        rcu_read_unlock();
 291#endif
 292}
 293
 294#else /* !CONFIG_NETFILTER */
 295#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 296#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
 297static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 298                                 struct sk_buff *skb,
 299                                 struct net_device *indev,
 300                                 struct net_device *outdev,
 301                                 int (*okfn)(struct sk_buff *), int thresh)
 302{
 303        return okfn(skb);
 304}
 305static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 306                          struct net_device *indev, struct net_device *outdev,
 307                          int (*okfn)(struct sk_buff *))
 308{
 309        return 1;
 310}
 311struct flowi;
 312static inline void
 313nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 314{
 315}
 316#endif /*CONFIG_NETFILTER*/
 317
 318#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 319extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 320void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 321extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 322
 323struct nf_conn;
 324enum ip_conntrack_info;
 325struct nlattr;
 326
 327struct nfq_ct_hook {
 328        size_t (*build_size)(const struct nf_conn *ct);
 329        int (*build)(struct sk_buff *skb, struct nf_conn *ct);
 330        int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 331        int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 332                             u32 portid, u32 report);
 333        void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 334                           enum ip_conntrack_info ctinfo, s32 off);
 335};
 336extern struct nfq_ct_hook __rcu *nfq_ct_hook;
 337#else
 338static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 339#endif
 340
 341#endif /*__LINUX_NETFILTER_H*/
 342