LXR linux-bk/include/linux/netfilter_arp/arp

   1/*
   2 *      Format of an ARP firewall descriptor
   3 *
   4 *      src, tgt, src_mask, tgt_mask, arpop, arpop_mask are always stored in
   5 *      network byte order.
   6 *      flags are stored in host byte order (of course).
   7 */
   8
   9#ifndef _ARPTABLES_H
  10#define _ARPTABLES_H
  11
  12#ifdef __KERNEL__
  13#include <linux/if.h>
  14#include <linux/types.h>
  15#include <linux/in.h>
  16#include <linux/if_arp.h>
  17#include <linux/skbuff.h>
  18#endif
  19#include <linux/compiler.h>
  20#include <linux/netfilter_arp.h>
  21
  22#define ARPT_FUNCTION_MAXNAMELEN 30
  23#define ARPT_TABLE_MAXNAMELEN 32
  24
  25#define ARPT_DEV_ADDR_LEN_MAX 16
  26
  27struct arpt_devaddr_info {
  28        char addr[ARPT_DEV_ADDR_LEN_MAX];
  29        char mask[ARPT_DEV_ADDR_LEN_MAX];
  30};
  31
  32/* Yes, Virginia, you have to zero the padding. */
  33struct arpt_arp {
  34        /* Source and target IP addr */
  35        struct in_addr src, tgt;
  36        /* Mask for src and target IP addr */
  37        struct in_addr smsk, tmsk;
  38
  39        /* Device hw address length, src+target device addresses */
  40        u_int8_t arhln, arhln_mask;
  41        struct arpt_devaddr_info src_devaddr;
  42        struct arpt_devaddr_info tgt_devaddr;
  43
  44        /* ARP operation code. */
  45        u_int16_t arpop, arpop_mask;
  46
  47        /* ARP hardware address and protocol address format. */
  48        u_int16_t arhrd, arhrd_mask;
  49        u_int16_t arpro, arpro_mask;
  50
  51        /* The protocol address length is only accepted if it is 4
  52         * so there is no use in offering a way to do filtering on it.
  53         */
  54
  55        char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
  56        unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
  57
  58        /* Flags word */
  59        u_int8_t flags;
  60        /* Inverse flags */
  61        u_int16_t invflags;
  62};
  63
  64struct arpt_entry_target
  65{
  66        union {
  67                struct {
  68                        u_int16_t target_size;
  69
  70                        /* Used by userspace */
  71                        char name[ARPT_FUNCTION_MAXNAMELEN];
  72                } user;
  73                struct {
  74                        u_int16_t target_size;
  75
  76                        /* Used inside the kernel */
  77                        struct arpt_target *target;
  78                } kernel;
  79
  80                /* Total length */
  81                u_int16_t target_size;
  82        } u;
  83
  84        unsigned char data[0];
  85};
  86
  87struct arpt_standard_target
  88{
  89        struct arpt_entry_target target;
  90        int verdict;
  91};
  92
  93struct arpt_counters
  94{
  95        u_int64_t pcnt, bcnt;                   /* Packet and byte counters */
  96};
  97
  98/* Values for "flag" field in struct arpt_ip (general arp structure).
  99 * No flags defined yet.
 100 */
 101#define ARPT_F_MASK             0x00    /* All possible flag bits mask. */
 102
 103/* Values for "inv" field in struct arpt_arp. */
 104#define ARPT_INV_VIA_IN         0x0001  /* Invert the sense of IN IFACE. */
 105#define ARPT_INV_VIA_OUT        0x0002  /* Invert the sense of OUT IFACE */
 106#define ARPT_INV_SRCIP          0x0004  /* Invert the sense of SRC IP. */
 107#define ARPT_INV_TGTIP          0x0008  /* Invert the sense of TGT IP. */
 108#define ARPT_INV_SRCDEVADDR     0x0010  /* Invert the sense of SRC DEV ADDR. */
 109#define ARPT_INV_TGTDEVADDR     0x0020  /* Invert the sense of TGT DEV ADDR. */
 110#define ARPT_INV_ARPOP          0x0040  /* Invert the sense of ARP OP. */
 111#define ARPT_INV_ARPHRD         0x0080  /* Invert the sense of ARP HRD. */
 112#define ARPT_INV_ARPPRO         0x0100  /* Invert the sense of ARP PRO. */
 113#define ARPT_INV_ARPHLN         0x0200  /* Invert the sense of ARP HLN. */
 114#define ARPT_INV_MASK           0x03FF  /* All possible flag bits mask. */
 115
 116/* This structure defines each of the firewall rules.  Consists of 3
 117   parts which are 1) general ARP header stuff 2) match specific
 118   stuff 3) the target to perform if the rule matches */
 119struct arpt_entry
 120{
 121        struct arpt_arp arp;
 122
 123        /* Size of arpt_entry + matches */
 124        u_int16_t target_offset;
 125        /* Size of arpt_entry + matches + target */
 126        u_int16_t next_offset;
 127
 128        /* Back pointer */
 129        unsigned int comefrom;
 130
 131        /* Packet and byte counters. */
 132        struct arpt_counters counters;
 133
 134        /* The matches (if any), then the target. */
 135        unsigned char elems[0];
 136};
 137
 138/*
 139 * New IP firewall options for [gs]etsockopt at the RAW IP level.
 140 * Unlike BSD Linux inherits IP options so you don't have to use a raw
 141 * socket for this. Instead we check rights in the calls.
 142 */
 143#define ARPT_BASE_CTL           96      /* base for firewall socket options */
 144
 145#define ARPT_SO_SET_REPLACE             (ARPT_BASE_CTL)
 146#define ARPT_SO_SET_ADD_COUNTERS        (ARPT_BASE_CTL + 1)
 147#define ARPT_SO_SET_MAX                 ARPT_SO_SET_ADD_COUNTERS
 148
 149#define ARPT_SO_GET_INFO                (ARPT_BASE_CTL)
 150#define ARPT_SO_GET_ENTRIES             (ARPT_BASE_CTL + 1)
 151#define ARPT_SO_GET_MAX                 ARPT_SO_GET_ENTRIES
 152
 153/* CONTINUE verdict for targets */
 154#define ARPT_CONTINUE 0xFFFFFFFF
 155
 156/* For standard target */
 157#define ARPT_RETURN (-NF_MAX_VERDICT - 1)
 158
 159/* The argument to ARPT_SO_GET_INFO */
 160struct arpt_getinfo
 161{
 162        /* Which table: caller fills this in. */
 163        char name[ARPT_TABLE_MAXNAMELEN];
 164
 165        /* Kernel fills these in. */
 166        /* Which hook entry points are valid: bitmask */
 167        unsigned int valid_hooks;
 168
 169        /* Hook entry points: one per netfilter hook. */
 170        unsigned int hook_entry[NF_ARP_NUMHOOKS];
 171
 172        /* Underflow points. */
 173        unsigned int underflow[NF_ARP_NUMHOOKS];
 174
 175        /* Number of entries */
 176        unsigned int num_entries;
 177
 178        /* Size of entries. */
 179        unsigned int size;
 180};
 181
 182/* The argument to ARPT_SO_SET_REPLACE. */
 183struct arpt_replace
 184{
 185        /* Which table. */
 186        char name[ARPT_TABLE_MAXNAMELEN];
 187
 188        /* Which hook entry points are valid: bitmask.  You can't
 189           change this. */
 190        unsigned int valid_hooks;
 191
 192        /* Number of entries */
 193        unsigned int num_entries;
 194
 195        /* Total size of new entries */
 196        unsigned int size;
 197
 198        /* Hook entry points. */
 199        unsigned int hook_entry[NF_ARP_NUMHOOKS];
 200
 201        /* Underflow points. */
 202        unsigned int underflow[NF_ARP_NUMHOOKS];
 203
 204        /* Information about old entries: */
 205        /* Number of counters (must be equal to current number of entries). */
 206        unsigned int num_counters;
 207        /* The old entries' counters. */
 208        struct arpt_counters __user *counters;
 209
 210        /* The entries (hang off end: not really an array). */
 211        struct arpt_entry entries[0];
 212};
 213
 214/* The argument to ARPT_SO_ADD_COUNTERS. */
 215struct arpt_counters_info
 216{
 217        /* Which table. */
 218        char name[ARPT_TABLE_MAXNAMELEN];
 219
 220        unsigned int num_counters;
 221
 222        /* The counters (actually `number' of these). */
 223        struct arpt_counters counters[0];
 224};
 225
 226/* The argument to ARPT_SO_GET_ENTRIES. */
 227struct arpt_get_entries
 228{
 229        /* Which table: user fills this in. */
 230        char name[ARPT_TABLE_MAXNAMELEN];
 231
 232        /* User fills this in: total entry size. */
 233        unsigned int size;
 234
 235        /* The entries. */
 236        struct arpt_entry entrytable[0];
 237};
 238
 239/* Standard return verdict, or do jump. */
 240#define ARPT_STANDARD_TARGET ""
 241/* Error verdict. */
 242#define ARPT_ERROR_TARGET "ERROR"
 243
 244/* Helper functions */
 245static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e)
 246{
 247        return (void *)e + e->target_offset;
 248}
 249
 250/* fn returns 0 to continue iteration */
 251#define ARPT_ENTRY_ITERATE(entries, size, fn, args...)          \
 252({                                                              \
 253        unsigned int __i;                                       \
 254        int __ret = 0;                                          \
 255        struct arpt_entry *__entry;                             \
 256                                                                \
 257        for (__i = 0; __i < (size); __i += __entry->next_offset) { \
 258                __entry = (void *)(entries) + __i;              \
 259                                                                \
 260                __ret = fn(__entry , ## args);                  \
 261                if (__ret != 0)                                 \
 262                        break;                                  \
 263        }                                                       \
 264        __ret;                                                  \
 265})
 266
 267/*
 268 *      Main firewall chains definitions and global var's definitions.
 269 */
 270#ifdef __KERNEL__
 271
 272/* Registration hooks for targets. */
 273struct arpt_target
 274{
 275        struct list_head list;
 276
 277        const char name[ARPT_FUNCTION_MAXNAMELEN];
 278
 279        /* Returns verdict. */
 280        unsigned int (*target)(struct sk_buff **pskb,
 281                               unsigned int hooknum,
 282                               const struct net_device *in,
 283                               const struct net_device *out,
 284                               const void *targinfo,
 285                               void *userdata);
 286
 287        /* Called when user tries to insert an entry of this type:
 288           hook_mask is a bitmask of hooks from which it can be
 289           called. */
 290        /* Should return true or false. */
 291        int (*checkentry)(const char *tablename,
 292                          const struct arpt_entry *e,
 293                          void *targinfo,
 294                          unsigned int targinfosize,
 295                          unsigned int hook_mask);
 296
 297        /* Called when entry of this type deleted. */
 298        void (*destroy)(void *targinfo, unsigned int targinfosize);
 299
 300        /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 301        struct module *me;
 302};
 303
 304extern int arpt_register_target(struct arpt_target *target);
 305extern void arpt_unregister_target(struct arpt_target *target);
 306
 307/* Furniture shopping... */
 308struct arpt_table
 309{
 310        struct list_head list;
 311
 312        /* A unique name... */
 313        char name[ARPT_TABLE_MAXNAMELEN];
 314
 315        /* Seed table: copied in register_table */
 316        struct arpt_replace *table;
 317
 318        /* What hooks you will enter on */
 319        unsigned int valid_hooks;
 320
 321        /* Lock for the curtain */
 322        rwlock_t lock;
 323
 324        /* Man behind the curtain... */
 325        struct arpt_table_info *private;
 326
 327        /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 328        struct module *me;
 329};
 330
 331extern int arpt_register_table(struct arpt_table *table);
 332extern void arpt_unregister_table(struct arpt_table *table);
 333extern unsigned int arpt_do_table(struct sk_buff **pskb,
 334                                  unsigned int hook,
 335                                  const struct net_device *in,
 336                                  const struct net_device *out,
 337                                  struct arpt_table *table,
 338                                  void *userdata);
 339
 340#define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1))
 341#endif /*__KERNEL__*/
 342#endif /* _ARPTABLES_H */
 343