release/src-rt-6.x/linux/linux-2.6/include/linux/netfilter.h

   1 #ifndef __LINUX_NETFILTER_H
   2 #define __LINUX_NETFILTER_H
   3
   4 #ifdef __KERNEL__
   5 #include <linux/init.h>
   6 #include <linux/types.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 #if defined(CONFIG_BCM_NAT) || defined(CONFIG_BCM_NAT_MODULE)
  25 #define NF_FAST_NAT 5
  26 #define NF_STOP 6
  27 #else
  28 #define NF_STOP 5
  29 #endif
  30 #define NF_MAX_VERDICT NF_STOP
  31
  32 /* we overload the higher bits for encoding auxiliary data such as the queue
  33  * number. Not nice, but better than additional function arguments. */
  34 #define NF_VERDICT_MASK 0x0000ffff
  35 #define NF_VERDICT_BITS 16
  36
  37 #define NF_VERDICT_QMASK 0xffff0000
  38 #define NF_VERDICT_QBITS 16
  39
  40 #define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE)
  41
  42 /* only for userspace compatibility */
  43 #ifndef __KERNEL__
  44 /* Generic cache responses from hook functions.
  45    <= 0x2000 is used for protocol-flags. */
  46 #define NFC_UNKNOWN 0x4000
  47 #define NFC_ALTERED 0x8000
  48 #endif
  49
  50 union nf_inet_addr {
  51         __u32           all[4];
  52         __be32          ip;
  53         __be32          ip6[4];
  54         struct in_addr  in;
  55         struct in6_addr in6;
  56 };
  57
  58 #ifdef __KERNEL__
  59 #ifdef CONFIG_NETFILTER
  60
  61 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
  62                                    const union nf_inet_addr *a2)
  63 {
  64         return a1->all[0] == a2->all[0] &&
  65                a1->all[1] == a2->all[1] &&
  66                a1->all[2] == a2->all[2] &&
  67                a1->all[3] == a2->all[3];
  68 }
  69
  70 extern void netfilter_init(void);
  71
  72 /* Largest hook number + 1 */
  73 #define NF_MAX_HOOKS 8
  74
  75 struct sk_buff;
  76 struct net_device;
  77
  78 typedef unsigned int nf_hookfn(unsigned int hooknum,
  79                                struct sk_buff *skb,
  80                                const struct net_device *in,
  81                                const struct net_device *out,
  82                                int (*okfn)(struct sk_buff *));
  83
  84 struct nf_hook_ops
  85 {
  86         struct list_head list;
  87
  88         /* User fills in from here down. */
  89         nf_hookfn *hook;
  90         struct module *owner;
  91         int pf;
  92         int hooknum;
  93         /* Hooks are ordered in ascending priority. */
  94         int priority;
  95 };
  96
  97 struct nf_sockopt_ops
  98 {
  99         struct list_head list;
 100
 101         int pf;
 102
 103         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
 104         int set_optmin;
 105         int set_optmax;
 106         int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
 107         int (*compat_set)(struct sock *sk, int optval,
 108                         void __user *user, unsigned int len);
 109
 110         int get_optmin;
 111         int get_optmax;
 112         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
 113         int (*compat_get)(struct sock *sk, int optval,
 114                         void __user *user, int *len);
 115
 116         /* Number of users inside set() or get(). */
 117         unsigned int use;
 118         struct task_struct *cleanup_task;
 119 };
 120
 121 /* Each queued (to userspace) skbuff has one of these. */
 122 struct nf_info
 123 {
 124         /* The ops struct which sent us to userspace. */
 125         struct nf_hook_ops *elem;
 126
 127         /* If we're sent to userspace, this keeps housekeeping info */
 128         int pf;
 129         unsigned int hook;
 130         struct net_device *indev, *outdev;
 131         int (*okfn)(struct sk_buff *);
 132 };
 133
 134 /* Function to register/unregister hook points. */
 135 int nf_register_hook(struct nf_hook_ops *reg);
 136 void nf_unregister_hook(struct nf_hook_ops *reg);
 137 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
 138 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
 139
 140 /* Functions to register get/setsockopt ranges (non-inclusive).  You
 141    need to check permissions yourself! */
 142 int nf_register_sockopt(struct nf_sockopt_ops *reg);
 143 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 144
 145 #ifdef CONFIG_SYSCTL
 146 /* Sysctl registration */
 147 struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
 148                                                   struct ctl_table *table);
 149 void nf_unregister_sysctl_table(struct ctl_table_header *header,
 150                                 struct ctl_table *table);
 151 extern struct ctl_table nf_net_netfilter_sysctl_path[];
 152 extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
 153 #endif /* CONFIG_SYSCTL */
 154
 155 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
 156
 157 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
 158  * disappear once iptables is replaced with pkttables.  Please DO NOT use them
 159  * for any new code! */
 160 #define NF_LOG_TCPSEQ           0x01    /* Log TCP sequence numbers */
 161 #define NF_LOG_TCPOPT           0x02    /* Log TCP options */
 162 #define NF_LOG_IPOPT            0x04    /* Log IP options */
 163 #define NF_LOG_UID              0x08    /* Log UID owning local socket */
 164 #define NF_LOG_MASK             0x0f
 165
 166 #define NF_LOG_TYPE_LOG         0x01
 167 #define NF_LOG_TYPE_ULOG        0x02
 168
 169 struct nf_loginfo {
 170         u_int8_t type;
 171         union {
 172                 struct {
 173                         u_int32_t copy_len;
 174                         u_int16_t group;
 175                         u_int16_t qthreshold;
 176                 } ulog;
 177                 struct {
 178                         u_int8_t level;
 179                         u_int8_t logflags;
 180                 } log;
 181         } u;
 182 };
 183
 184 typedef void nf_logfn(unsigned int pf,
 185                       unsigned int hooknum,
 186                       const struct sk_buff *skb,
 187                       const struct net_device *in,
 188                       const struct net_device *out,
 189                       const struct nf_loginfo *li,
 190                       const char *prefix);
 191
 192 struct nf_logger {
 193         struct module   *me;
 194         nf_logfn        *logfn;
 195         char            *name;
 196 };
 197
 198 /* Function to register/unregister log function. */
 199 int nf_log_register(int pf, struct nf_logger *logger);
 200 void nf_log_unregister(struct nf_logger *logger);
 201 void nf_log_unregister_pf(int pf);
 202
 203 /* Calls the registered backend logging function */
 204 void nf_log_packet(int pf,
 205                    unsigned int hooknum,
 206                    const struct sk_buff *skb,
 207                    const struct net_device *in,
 208                    const struct net_device *out,
 209                    struct nf_loginfo *li,
 210                    const char *fmt, ...);
 211
 212 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,
 213                  struct net_device *indev, struct net_device *outdev,
 214                  int (*okfn)(struct sk_buff *), int thresh);
 215
 216 /**
 217  *      nf_hook_thresh - call a netfilter hook
 218  *
 219  *      Returns 1 if the hook has allowed the packet to pass.  The function
 220  *      okfn must be invoked by the caller in this case.  Any other return
 221  *      value indicates the packet has been consumed by the hook.
 222  */
 223 static inline int nf_hook_thresh(int pf, unsigned int hook,
 224                                  struct sk_buff *skb,
 225                                  struct net_device *indev,
 226                                  struct net_device *outdev,
 227                                  int (*okfn)(struct sk_buff *), int thresh,
 228                                  int cond)
 229 {
 230         if (!cond)
 231                 return 1;
 232 #ifndef CONFIG_NETFILTER_DEBUG
 233         if (list_empty(&nf_hooks[pf][hook]))
 234                 return 1;
 235 #endif
 236         return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
 237 }
 238
 239 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb,
 240                           struct net_device *indev, struct net_device *outdev,
 241                           int (*okfn)(struct sk_buff *))
 242 {
 243         return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1);
 244 }
 245
 246 /* Activate hook; either okfn or kfree_skb called, unless a hook
 247    returns NF_STOLEN (in which case, it's up to the hook to deal with
 248    the consequences).
 249
 250    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
 251    accepted.
 252 */
 253
 254 /* RR:
 255    > I don't want nf_hook to return anything because people might forget
 256    > about async and trust the return value to mean "packet was ok".
 257
 258    AK:
 259    Just document it clearly, then you can expect some sense from kernel
 260    coders :)
 261 */
 262
 263 /* This is gross, but inline doesn't cut it for avoiding the function
 264    call in fast path: gcc doesn't inline (needs value tracking?). --RR */
 265
 266 /* HX: It's slightly less gross now. */
 267
 268 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh)             \
 269 ({int __ret;                                                                   \
 270 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\
 271         __ret = (okfn)(skb);                                                   \
 272 __ret;})
 273
 274 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond)                 \
 275 ({int __ret;                                                                   \
 276 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
 277         __ret = (okfn)(skb);                                                   \
 278 __ret;})
 279
 280 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
 281         NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
 282
 283 /* Call setsockopt() */
 284 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
 285                   int len);
 286 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
 287                   int *len);
 288
 289 int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
 290                 char __user *opt, int len);
 291 int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
 292                 char __user *opt, int *len);
 293
 294 /* Packet queuing */
 295 struct nf_queue_handler {
 296         int (*outfn)(struct sk_buff *skb, struct nf_info *info,
 297                      unsigned int queuenum, void *data);
 298         void *data;
 299         char *name;
 300 };
 301 extern int nf_register_queue_handler(int pf,
 302                                      struct nf_queue_handler *qh);
 303 extern int nf_unregister_queue_handler(int pf);
 304 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
 305 extern void nf_reinject(struct sk_buff *skb,
 306                         struct nf_info *info,
 307                         unsigned int verdict);
 308
 309 /* FIXME: Before cache is ever used, this must be implemented for real. */
 310 extern void nf_invalidate_cache(int pf);
 311
 312 /* Call this before modifying an existing packet: ensures it is
 313    modifiable and linear to the point you care about (writable_len).
 314    Returns true or false. */
 315 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 316
 317 static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
 318 {
 319         __be32 diff[] = { ~from, to };
 320
 321         *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
 322 }
 323
 324 static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to)
 325 {
 326         nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to);
 327 }
 328
 329 extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 330                                       __be32 from, __be32 to, int pseudohdr);
 331
 332 static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
 333                                       __be16 from, __be16 to, int pseudohdr)
 334 {
 335         nf_proto_csum_replace4(sum, skb, (__force __be32)from,
 336                                 (__force __be32)to, pseudohdr);
 337 }
 338
 339 struct flowi;
 340
 341 struct nf_afinfo {
 342         unsigned short  family;
 343         __sum16         (*checksum)(struct sk_buff *skb, unsigned int hook,
 344                                     unsigned int dataoff, u_int8_t protocol);
 345         int             (*route)(struct dst_entry **dst, struct flowi *fl);
 346         void            (*saveroute)(const struct sk_buff *skb,
 347                                      struct nf_info *info);
 348         int             (*reroute)(struct sk_buff *skb,
 349                                    const struct nf_info *info);
 350         int             route_key_size;
 351 };
 352
 353 extern struct nf_afinfo *nf_afinfo[];
 354 static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
 355 {
 356         return rcu_dereference(nf_afinfo[family]);
 357 }
 358
 359 static inline __sum16
 360 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
 361             u_int8_t protocol, unsigned short family)
 362 {
 363         struct nf_afinfo *afinfo;
 364         __sum16 csum = 0;
 365
 366         rcu_read_lock();
 367         afinfo = nf_get_afinfo(family);
 368         if (afinfo)
 369                 csum = afinfo->checksum(skb, hook, dataoff, protocol);
 370         rcu_read_unlock();
 371         return csum;
 372 }
 373
 374 extern int nf_register_afinfo(struct nf_afinfo *afinfo);
 375 extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
 376
 377 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
 378
 379 #include <net/flow.h>
 380 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
 381
 382 static inline void
 383 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
 384 {
 385 #if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
 386         void (*decodefn)(struct sk_buff *, struct flowi *);
 387
 388         if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
 389                 decodefn(skb, fl);
 390 #endif
 391 }
 392
 393 #ifdef CONFIG_PROC_FS
 394 #include <linux/proc_fs.h>
 395 extern struct proc_dir_entry *proc_net_netfilter;
 396 #endif
 397
 398 #else /* !CONFIG_NETFILTER */
 399 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 400 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
 401 static inline int nf_hook_thresh(int pf, unsigned int hook,
 402                                  struct sk_buff *skb,
 403                                  struct net_device *indev,
 404                                  struct net_device *outdev,
 405                                  int (*okfn)(struct sk_buff *), int thresh,
 406                                  int cond)
 407 {
 408         return okfn(skb);
 409 }
 410 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb,
 411                           struct net_device *indev, struct net_device *outdev,
 412                           int (*okfn)(struct sk_buff *))
 413 {
 414         return 1;
 415 }
 416 struct flowi;
 417 static inline void
 418 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
 419 #endif /*CONFIG_NETFILTER*/
 420
 421 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 422 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
 423 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
 424 extern void (*nf_ct_destroy)(struct nf_conntrack *);
 425 #else
 426 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
 427 #endif
 428
 429 #endif /*__KERNEL__*/
 430 #endif /*__LINUX_NETFILTER_H*/