release/src-rt-6.x.4708/linux/linux-2.6.36/include/linux/netfilter.h

   1 /* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */
   2 #ifndef __LINUX_NETFILTER_H
   3 #define __LINUX_NETFILTER_H
   4
   5 #ifdef __KERNEL__
   6 #include <linux/init.h>
   7 #include <linux/skbuff.h>
   8 #include <linux/net.h>
   9 #include <linux/if.h>
  10 #include <linux/in.h>
  11 #include <linux/in6.h>
  12 #include <linux/wait.h>
  13 #include <linux/list.h>
  14 #endif
  15 #include <linux/types.h>
  16 #include <linux/compiler.h>
  17
  18 /* Responses from hook functions. */
  19 #define NF_DROP 0
  20 #define NF_ACCEPT 1
  21 #define NF_STOLEN 2
  22 #define NF_QUEUE 3
  23 #define NF_REPEAT 4
  24 #define NF_STOP 5
  25 #define NF_MAX_VERDICT NF_STOP
  26
  27 /* we overload the higher bits for encoding auxiliary data such as the queue
  28  * number or errno values. Not nice, but better than additional function
  29  * arguments. */
  30 #define NF_VERDICT_MASK 0x000000ff
  31
  32 /* extra verdict flags have mask 0x0000ff00 */
  33 #define NF_VERDICT_FLAG_QUEUE_BYPASS  0x00008000
  34
  35 /* queue number (NF_QUEUE) or errno (NF_DROP) */
  36 #define NF_VERDICT_QMASK 0xffff0000
  37 #define NF_VERDICT_QBITS 16
  38
  39 #define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE)
  40
  41 #define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP)
  42
  43 /* only for userspace compatibility */
  44 #ifndef __KERNEL__
  45 /* Generic cache responses from hook functions.
  46    <= 0x2000 is used for protocol-flags. */
  47 #define NFC_UNKNOWN 0x4000
  48 #define NFC_ALTERED 0x8000
  49
  50 /* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
  51 #define NF_VERDICT_BITS 16
  52 #endif
  53
  54 enum nf_inet_hooks {
  55         NF_INET_PRE_ROUTING,
  56         NF_INET_LOCAL_IN,
  57         NF_INET_FORWARD,
  58         NF_INET_LOCAL_OUT,
  59         NF_INET_POST_ROUTING,
  60         NF_INET_NUMHOOKS
  61 };
  62
  63 enum {
  64         NFPROTO_UNSPEC =  0,
  65         NFPROTO_IPV4   =  2,
  66         NFPROTO_ARP    =  3,
  67         NFPROTO_BRIDGE =  7,
  68         NFPROTO_IPV6   = 10,
  69         NFPROTO_DECNET = 12,
  70         NFPROTO_NUMPROTO,
  71 };
  72
  73 union nf_inet_addr {
  74         __u32           all[4];
  75         __be32          ip;
  76         __be32          ip6[4];
  77         struct in_addr  in;
  78         struct in6_addr in6;
  79 };
  80
  81 #ifdef __KERNEL__
  82 #ifdef CONFIG_NETFILTER
  83 static inline int NF_DROP_GETERR(int verdict)
  84 {
  85         return -(verdict >> NF_VERDICT_QBITS);
  86 }
  87
  88 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  89                                    const union nf_inet_addr *a2)
  90 {
  91         return a1->all[0] == a2->all[0] &&
  92                a1->all[1] == a2->all[1] &&
  93                a1->all[2] == a2->all[2] &&
  94                a1->all[3] == a2->all[3];
  95 }
  96
  97 extern void netfilter_init(void);
  98
  99 /* Largest hook number + 1 */
 100 #define NF_MAX_HOOKS 8
 101
 102 struct sk_buff;
 103
 104 typedef unsigned int nf_hookfn(unsigned int hooknum,
 105                                struct sk_buff *skb,
 106                                const struct net_device *in,
 107                                const struct net_device *out,
 108                                int (*okfn)(struct sk_buff *));
 109
 110 struct nf_hook_ops {
 111         struct list_head list;
 112
 113         /* User fills in from here down. */
 114         nf_hookfn *hook;
 115         struct module *owner;
 116         u_int8_t pf;
 117         unsigned int hooknum;
 118         /* Hooks are ordered in ascending priority. */
 119         int priority;
 120 };
 121
 122 struct nf_sockopt_ops {
 123         struct list_head list;
 124
 125         u_int8_t pf;
 126
 127         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 128         int set_optmin;
 129         int set_optmax;
 130         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 131 #ifdef CONFIG_COMPAT
 132         int (*compat_set)(struct sock *sk, int optval,
 133                         void __user *user, unsigned int len);
 134 #endif
 135         int get_optmin;
 136         int get_optmax;
 137         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 138 #ifdef CONFIG_COMPAT
 139         int (*compat_get)(struct sock *sk, int optval,
 140                         void __user *user, int *len);
 141 #endif
 142         /* Use the module struct to lock set/get code in place */
 143         struct module *owner;
 144 };
 145
 146 /* Function to register/unregister hook points. */
 147 int nf_register_hook(struct nf_hook_ops *reg);
 148 void nf_unregister_hook(struct nf_hook_ops *reg);
 149 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 150 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 151
 152 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 153    need to check permissions yourself! */
 154 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 155 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 156
 157 #ifdef CONFIG_SYSCTL
 158 /* Sysctl registration */
 159 extern struct ctl_path nf_net_netfilter_sysctl_path[];
 160 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
 161 #endif /* CONFIG_SYSCTL */
 162
 163 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 164
 165 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 166                  struct net_device *indev, struct net_device *outdev,
 167                  int (*okfn)(struct sk_buff *), int thresh);
 168
 169 /**
 170  *      nf_hook_thresh - call a netfilter hook
 171  *
 172  *      Returns 1 if the hook has allowed the packet to pass.  The function
 173  *      okfn must be invoked by the caller in this case.  Any other return
 174  *      value indicates the packet has been consumed by the hook.
 175  */
 176 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 177                                  struct sk_buff *skb,
 178                                  struct net_device *indev,
 179                                  struct net_device *outdev,
 180                                  int (*okfn)(struct sk_buff *), int thresh)
 181 {
 182 #ifndef CONFIG_NETFILTER_DEBUG
 183         if (skb->tcpf_smb)
 184                 return 1;
 185         else if (list_empty(&nf_hooks[pf][hook]))
 186                 return 1;
 187 #endif
 188         return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
 189 }
 190
 191 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 192                           struct net_device *indev, struct net_device *outdev,
 193                           int (*okfn)(struct sk_buff *))
 194 {
 195         return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
 196 }
 197
 198 /* Activate hook; either okfn or kfree_skb called, unless a hook
 199    returns NF_STOLEN (in which case, it's up to the hook to deal with
 200    the consequences).
 201
 202    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 203    accepted.
 204 */
 205
 206 /* RR:
 207    > I don't want nf_hook to return anything because people might forget
 208    > about async and trust the return value to mean "packet was ok".
 209
 210    AK:
 211    Just document it clearly, then you can expect some sense from kernel
 212    coders :)
 213 */
 214
 215 static inline int
 216 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 217                struct net_device *in, struct net_device *out,
 218                int (*okfn)(struct sk_buff *), int thresh)
 219 {
 220         int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
 221         if (ret == 1)
 222                 ret = okfn(skb);
 223         return ret;
 224 }
 225
 226 static inline int
 227 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 228              struct net_device *in, struct net_device *out,
 229              int (*okfn)(struct sk_buff *), bool cond)
 230 {
 231         int ret;
 232
 233         if (!cond ||
 234             ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
 235                 ret = okfn(skb);
 236         return ret;
 237 }
 238
 239 static inline int
 240 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
 241         struct net_device *in, struct net_device *out,
 242         int (*okfn)(struct sk_buff *))
 243 {
 244         return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
 245 }
 246
 247 /* Call setsockopt() */
 248 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 249                   unsigned int len);
 250 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
 251                   int *len);
 252 #ifdef CONFIG_COMPAT
 253 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
 254                 char __user *opt, unsigned int len);
 255 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
 256                 char __user *opt, int *len);
 257 #endif
 258
 259 /* Call this before modifying an existing packet: ensures it is
 260    modifiable and linear to the point you care about (writable_len).
 261    Returns true or false. */
 262 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 263
 264 struct flowi;
 265 struct nf_queue_entry;
 266
 267 struct nf_afinfo {
 268         unsigned short  family;
 269         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 270                                     unsigned int dataoff, u_int8_t protocol);
 271         __sum16         (*checksum_partial)(struct sk_buff *skb,
 272                                             unsigned int hook,
 273                                             unsigned int dataoff,
 274                                             unsigned int len,
 275                                             u_int8_t protocol);
 276         int             (*route)(struct dst_entry **dst, struct flowi *fl);
 277         void            (*saveroute)(const struct sk_buff *skb,
 278                                      struct nf_queue_entry *entry);
 279         int             (*reroute)(struct sk_buff *skb,
 280                                    const struct nf_queue_entry *entry);
 281         int             route_key_size;
 282 };
 283
 284 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO];
 285 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
 286 {
 287         return rcu_dereference(nf_afinfo[family]);
 288 }
 289
 290 static inline __sum16
 291 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 292             u_int8_t protocol, unsigned short family)
 293 {
 294         const struct nf_afinfo *afinfo;
 295         __sum16 csum = 0;
 296
 297         rcu_read_lock();
 298         afinfo = nf_get_afinfo(family);
 299         if (afinfo)
 300                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 301         rcu_read_unlock();
 302         return csum;
 303 }
 304
 305 static inline __sum16
 306 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
 307                     unsigned int dataoff, unsigned int len,
 308                     u_int8_t protocol, unsigned short family)
 309 {
 310         const struct nf_afinfo *afinfo;
 311         __sum16 csum = 0;
 312
 313         rcu_read_lock();
 314         afinfo = nf_get_afinfo(family);
 315         if (afinfo)
 316                 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
 317                                                 protocol);
 318         rcu_read_unlock();
 319         return csum;
 320 }
 321
 322 extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
 323 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
 324
 325 #include <net/flow.h>
 326 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
 327
 328 static inline void
 329 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 330 {
 331 #ifdef CONFIG_NF_NAT_NEEDED
 332         void (*decodefn)(struct sk_buff *, struct flowi *);
 333
 334         if (family == AF_INET) {
 335                 rcu_read_lock();
 336                 decodefn = rcu_dereference(ip_nat_decode_session);
 337                 if (decodefn)
 338                         decodefn(skb, fl);
 339                 rcu_read_unlock();
 340         }
 341 #endif
 342 }
 343
 344 #ifdef CONFIG_PROC_FS
 345 #include <linux/proc_fs.h>
 346 extern struct proc_dir_entry *proc_net_netfilter;
 347 #endif
 348
 349 #else /* !CONFIG_NETFILTER */
 350 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 351 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
 352 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 353                                  struct sk_buff *skb,
 354                                  struct net_device *indev,
 355                                  struct net_device *outdev,
 356                                  int (*okfn)(struct sk_buff *), int thresh)
 357 {
 358         return okfn(skb);
 359 }
 360 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
 361                           struct net_device *indev, struct net_device *outdev,
 362                           int (*okfn)(struct sk_buff *))
 363 {
 364         return 1;
 365 }
 366 struct flowi;
 367 static inline void
 368 nf_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 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
 375 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
 376 extern void (*nf_ct_destroy)(struct nf_conntrack *);
 377 #else
 378 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 379 #endif
 380
 381 #endif /*__KERNEL__*/
 382 #endif /*__LINUX_NETFILTER_H*/