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 <uapi/linux/netfilter.h>
  14#ifdef CONFIG_NETFILTER
  15static inline int NF_DROP_GETERR(int verdict)
  16{
  17        return -(verdict >> NF_VERDICT_QBITS);
  18}
  19
  20static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  21                                   const union nf_inet_addr *a2)
  22{
  23        return a1->all[0] == a2->all[0] &&
  24               a1->all[1] == a2->all[1] &&
  25               a1->all[2] == a2->all[2] &&
  26               a1->all[3] == a2->all[3];
  27}
  28
  29static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
  30                                     union nf_inet_addr *result,
  31                                     const union nf_inet_addr *mask)
  32{
  33        result->all[0] = a1->all[0] & mask->all[0];
  34        result->all[1] = a1->all[1] & mask->all[1];
  35        result->all[2] = a1->all[2] & mask->all[2];
  36        result->all[3] = a1->all[3] & mask->all[3];
  37}
  38
  39int netfilter_init(void);
  40
  41/* Largest hook number + 1 */
  42#define NF_MAX_HOOKS 8
  43
  44struct sk_buff;
  45
  46struct nf_hook_ops;
  47typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops,
  48                               struct sk_buff *skb,
  49                               const struct net_device *in,
  50                               const struct net_device *out,
  51                               int (*okfn)(struct sk_buff *));
  52
  53struct nf_hook_ops {
  54        struct list_head list;
  55
  56        /* User fills in from here down. */
  57        nf_hookfn       *hook;
  58        struct module   *owner;
  59        void            *priv;
  60        u_int8_t        pf;
  61        unsigned int    hooknum;
  62        /* Hooks are ordered in ascending priority. */
  63        int             priority;
  64};
  65
  66struct nf_sockopt_ops {
  67        struct list_head list;
  68
  69        u_int8_t pf;
  70
  71        /* Non-inclusive ranges: use 0/0/NULL to never get called. */
  72        int set_optmin;
  73        int set_optmax;
  74        int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
  75#ifdef CONFIG_COMPAT
  76        int (*compat_set)(struct sock *sk, int optval,
  77                        void __user *user, unsigned int len);
  78#endif
  79        int get_optmin;
  80        int get_optmax;
  81        int (*get)(struct sock *sk, int optval, void __user *user, int *len);
  82#ifdef CONFIG_COMPAT
  83        int (*compat_get)(struct sock *sk, int optval,
  84                        void __user *user, int *len);
  85#endif
  86        /* Use the module struct to lock set/get code in place */
  87        struct module *owner;
  88};
  89
  90/* Function to register/unregister hook points. */
  91int nf_register_hook(struct nf_hook_ops *reg);
  92void nf_unregister_hook(struct nf_hook_ops *reg);
  93int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
  94void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
  95
  96/* Functions to register get/setsockopt ranges (non-inclusive).  You
  97   need to check permissions yourself! */
  98int nf_register_sockopt(struct nf_sockopt_ops *reg);
  99void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 100
 101extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 102
 103#ifdef HAVE_JUMP_LABEL
 104extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 105
 106static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
 107{
 108        if (__builtin_constant_p(pf) &&
 109            __builtin_constant_p(hook))
 110                return static_key_false(&nf_hooks_needed[pf][hook]);
 111
 112        return !list_empty(&nf_hooks[pf][hook]);
 113}
 114#else
 115static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
 116{
 117        return !list_empty(&nf_hooks[pf][hook]);
 118}
 119#endif
 120
 121int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 122                 struct net_device *indev, struct net_device *outdev,
 123                 int (*okfn)(struct sk_buff *), int thresh);
 124
 125/**
 126 *      nf_hook_thresh - call a netfilter hook
 127 *      
 128 *      Returns 1 if the hook has allowed the packet to pass.  The function
 129 *      okfn must be invoked by the caller in this case.  Any other return
 130 *      value indicates the packet has been consumed by the hook.
 131 */
 132static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 133                                 struct sk_buff *skb,
 134                                 struct net_device *indev,
 135                                 struct net_device *outdev,
 136                                 int (*okfn)(struct sk_buff *), int thresh)
 137{
 138        if (nf_hooks_active(pf, hook))
 139                return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
 140        return 1;
 141}
 142
 143static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 144                          struct net_device *indev, struct net_device *outdev,
 145                          int (*okfn)(struct sk_buff *))
 146{
 147        return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
 148}
 149                   
 150/* Activate hook; either okfn or kfree_skb called, unless a hook
 151   returns NF_STOLEN (in which case, it's up to the hook to deal with
 152   the consequences).
 153
 154   Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 155   accepted.
 156*/
 157
 158/* RR:
 159   > I don't want nf_hook to return anything because people might forget
 160   > about async and trust the return value to mean "packet was ok".
 161
 162   AK:
 163   Just document it clearly, then you can expect some sense from kernel
 164   coders :)
 165*/
 166
 167static inline int
 168NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 169               struct net_device *in, struct net_device *out,
 170               int (*okfn)(struct sk_buff *), int thresh)
 171{
 172        int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
 173        if (ret == 1)
 174                ret = okfn(skb);
 175        return ret;
 176}
 177
 178static inline int
 179NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 180             struct net_device *in, struct net_device *out,
 181             int (*okfn)(struct sk_buff *), bool cond)
 182{
 183        int ret;
 184
 185        if (!cond ||
 186            ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
 187                ret = okfn(skb);
 188        return ret;
 189}
 190
 191static inline int
 192NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 193        struct net_device *in, struct net_device *out,
 194        int (*okfn)(struct sk_buff *))
 195{
 196        return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
 197}
 198
 199/* Call setsockopt() */
 200int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 201                  unsigned int len);
 202int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 203                  int *len);
 204#ifdef CONFIG_COMPAT
 205int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 206                char __user *opt, unsigned int len);
 207int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 208                char __user *opt, int *len);
 209#endif
 210
 211/* Call this before modifying an existing packet: ensures it is
 212   modifiable and linear to the point you care about (writable_len).
 213   Returns true or false. */
 214int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 215
 216struct flowi;
 217struct nf_queue_entry;
 218
 219struct nf_afinfo {
 220        unsigned short  family;
 221        __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 222                                    unsigned int dataoff, u_int8_t protocol);
 223        __sum16         (*checksum_partial)(struct sk_buff *skb,
 224                                            unsigned int hook,
 225                                            unsigned int dataoff,
 226                                            unsigned int len,
 227                                            u_int8_t protocol);
 228        int             (*route)(struct net *net, struct dst_entry **dst,
 229                                 struct flowi *fl, bool strict);
 230        void            (*saveroute)(const struct sk_buff *skb,
 231                                     struct nf_queue_entry *entry);
 232        int             (*reroute)(struct sk_buff *skb,
 233                                   const struct nf_queue_entry *entry);
 234        int             route_key_size;
 235};
 236
 237extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
 238static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 239{
 240        return rcu_dereference(nf_afinfo[family]);
 241}
 242
 243static inline __sum16
 244nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 245            u_int8_t protocol, unsigned short family)
 246{
 247        const struct nf_afinfo *afinfo;
 248        __sum16 csum = 0;
 249
 250        rcu_read_lock();
 251        afinfo = nf_get_afinfo(family);
 252        if (afinfo)
 253                csum = afinfo->checksum(skb, hook, dataoff, protocol);
 254        rcu_read_unlock();
 255        return csum;
 256}
 257
 258static inline __sum16
 259nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 260                    unsigned int dataoff, unsigned int len,
 261                    u_int8_t protocol, unsigned short family)
 262{
 263        const struct nf_afinfo *afinfo;
 264        __sum16 csum = 0;
 265
 266        rcu_read_lock();
 267        afinfo = nf_get_afinfo(family);
 268        if (afinfo)
 269                csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 270                                                protocol);
 271        rcu_read_unlock();
 272        return csum;
 273}
 274
 275int nf_register_afinfo(const struct nf_afinfo *afinfo);
 276void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 277
 278#include <net/flow.h>
 279extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
 280
 281static inline void
 282nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 283{
 284#ifdef CONFIG_NF_NAT_NEEDED
 285        void (*decodefn)(struct sk_buff *, struct flowi *);
 286
 287        rcu_read_lock();
 288        decodefn = rcu_dereference(nf_nat_decode_session_hook);
 289        if (decodefn)
 290                decodefn(skb, fl);
 291        rcu_read_unlock();
 292#endif
 293}
 294
 295#else /* !CONFIG_NETFILTER */
 296#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 297#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
 298static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 299                                 struct sk_buff *skb,
 300                                 struct net_device *indev,
 301                                 struct net_device *outdev,
 302                                 int (*okfn)(struct sk_buff *), int thresh)
 303{
 304        return okfn(skb);
 305}
 306static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 307                          struct net_device *indev, struct net_device *outdev,
 308                          int (*okfn)(struct sk_buff *))
 309{
 310        return 1;
 311}
 312struct flowi;
 313static inline void
 314nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 315{
 316}
 317#endif /*CONFIG_NETFILTER*/
 318
 319#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 320extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 321void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 322extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
 323
 324struct nf_conn;
 325enum ip_conntrack_info;
 326struct nlattr;
 327
 328struct nfq_ct_hook {
 329        size_t (*build_size)(const struct nf_conn *ct);
 330        int (*build)(struct sk_buff *skb, struct nf_conn *ct);
 331        int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
 332        int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
 333                             u32 portid, u32 report);
 334        void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 335                           enum ip_conntrack_info ctinfo, s32 off);
 336};
 337extern struct nfq_ct_hook __rcu *nfq_ct_hook;
 338#else
 339static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 340#endif
 341
 342#endif /*__LINUX_NETFILTER_H*/
 343