include/linux/netfilter_arp/arp_tables.h

   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 #include <linux/netfilter/x_tables.h>
  23
  24 #define ARPT_FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
  25 #define ARPT_TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
  26 #define arpt_target xt_target
  27 #define arpt_table xt_table
  28
  29 #define ARPT_DEV_ADDR_LEN_MAX 16
  30
  31 struct arpt_devaddr_info {
  32         char addr[ARPT_DEV_ADDR_LEN_MAX];
  33         char mask[ARPT_DEV_ADDR_LEN_MAX];
  34 };
  35
  36 /* Yes, Virginia, you have to zero the padding. */
  37 struct arpt_arp {
  38         /* Source and target IP addr */
  39         struct in_addr src, tgt;
  40         /* Mask for src and target IP addr */
  41         struct in_addr smsk, tmsk;
  42
  43         /* Device hw address length, src+target device addresses */
  44         u_int8_t arhln, arhln_mask;
  45         struct arpt_devaddr_info src_devaddr;
  46         struct arpt_devaddr_info tgt_devaddr;
  47
  48         /* ARP operation code. */
  49         __be16 arpop, arpop_mask;
  50
  51         /* ARP hardware address and protocol address format. */
  52         __be16 arhrd, arhrd_mask;
  53         __be16 arpro, arpro_mask;
  54
  55         /* The protocol address length is only accepted if it is 4
  56          * so there is no use in offering a way to do filtering on it.
  57          */
  58
  59         char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
  60         unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
  61
  62         /* Flags word */
  63         u_int8_t flags;
  64         /* Inverse flags */
  65         u_int16_t invflags;
  66 };
  67
  68 #define arpt_entry_target xt_entry_target
  69 #define arpt_standard_target xt_standard_target
  70
  71 /* Values for "flag" field in struct arpt_ip (general arp structure).
  72  * No flags defined yet.
  73  */
  74 #define ARPT_F_MASK             0x00    /* All possible flag bits mask. */
  75
  76 /* Values for "inv" field in struct arpt_arp. */
  77 #define ARPT_INV_VIA_IN         0x0001  /* Invert the sense of IN IFACE. */
  78 #define ARPT_INV_VIA_OUT        0x0002  /* Invert the sense of OUT IFACE */
  79 #define ARPT_INV_SRCIP          0x0004  /* Invert the sense of SRC IP. */
  80 #define ARPT_INV_TGTIP          0x0008  /* Invert the sense of TGT IP. */
  81 #define ARPT_INV_SRCDEVADDR     0x0010  /* Invert the sense of SRC DEV ADDR. */
  82 #define ARPT_INV_TGTDEVADDR     0x0020  /* Invert the sense of TGT DEV ADDR. */
  83 #define ARPT_INV_ARPOP          0x0040  /* Invert the sense of ARP OP. */
  84 #define ARPT_INV_ARPHRD         0x0080  /* Invert the sense of ARP HRD. */
  85 #define ARPT_INV_ARPPRO         0x0100  /* Invert the sense of ARP PRO. */
  86 #define ARPT_INV_ARPHLN         0x0200  /* Invert the sense of ARP HLN. */
  87 #define ARPT_INV_MASK           0x03FF  /* All possible flag bits mask. */
  88
  89 /* This structure defines each of the firewall rules.  Consists of 3
  90    parts which are 1) general ARP header stuff 2) match specific
  91    stuff 3) the target to perform if the rule matches */
  92 struct arpt_entry
  93 {
  94         struct arpt_arp arp;
  95
  96         /* Size of arpt_entry + matches */
  97         u_int16_t target_offset;
  98         /* Size of arpt_entry + matches + target */
  99         u_int16_t next_offset;
 100
 101         /* Back pointer */
 102         unsigned int comefrom;
 103
 104         /* Packet and byte counters. */
 105         struct xt_counters counters;
 106
 107         /* The matches (if any), then the target. */
 108         unsigned char elems[0];
 109 };
 110
 111 /*
 112  * New IP firewall options for [gs]etsockopt at the RAW IP level.
 113  * Unlike BSD Linux inherits IP options so you don't have to use a raw
 114  * socket for this. Instead we check rights in the calls.
 115  *
 116  * ATTENTION: check linux/in.h before adding new number here.
 117  */
 118 #define ARPT_BASE_CTL           96
 119
 120 #define ARPT_SO_SET_REPLACE             (ARPT_BASE_CTL)
 121 #define ARPT_SO_SET_ADD_COUNTERS        (ARPT_BASE_CTL + 1)
 122 #define ARPT_SO_SET_MAX                 ARPT_SO_SET_ADD_COUNTERS
 123
 124 #define ARPT_SO_GET_INFO                (ARPT_BASE_CTL)
 125 #define ARPT_SO_GET_ENTRIES             (ARPT_BASE_CTL + 1)
 126 /* #define ARPT_SO_GET_REVISION_MATCH   (APRT_BASE_CTL + 2) */
 127 #define ARPT_SO_GET_REVISION_TARGET     (ARPT_BASE_CTL + 3)
 128 #define ARPT_SO_GET_MAX                 (ARPT_SO_GET_REVISION_TARGET)
 129
 130 /* CONTINUE verdict for targets */
 131 #define ARPT_CONTINUE XT_CONTINUE
 132
 133 /* For standard target */
 134 #define ARPT_RETURN XT_RETURN
 135
 136 /* The argument to ARPT_SO_GET_INFO */
 137 struct arpt_getinfo
 138 {
 139         /* Which table: caller fills this in. */
 140         char name[ARPT_TABLE_MAXNAMELEN];
 141
 142         /* Kernel fills these in. */
 143         /* Which hook entry points are valid: bitmask */
 144         unsigned int valid_hooks;
 145
 146         /* Hook entry points: one per netfilter hook. */
 147         unsigned int hook_entry[NF_ARP_NUMHOOKS];
 148
 149         /* Underflow points. */
 150         unsigned int underflow[NF_ARP_NUMHOOKS];
 151
 152         /* Number of entries */
 153         unsigned int num_entries;
 154
 155         /* Size of entries. */
 156         unsigned int size;
 157 };
 158
 159 /* The argument to ARPT_SO_SET_REPLACE. */
 160 struct arpt_replace
 161 {
 162         /* Which table. */
 163         char name[ARPT_TABLE_MAXNAMELEN];
 164
 165         /* Which hook entry points are valid: bitmask.  You can't
 166            change this. */
 167         unsigned int valid_hooks;
 168
 169         /* Number of entries */
 170         unsigned int num_entries;
 171
 172         /* Total size of new entries */
 173         unsigned int size;
 174
 175         /* Hook entry points. */
 176         unsigned int hook_entry[NF_ARP_NUMHOOKS];
 177
 178         /* Underflow points. */
 179         unsigned int underflow[NF_ARP_NUMHOOKS];
 180
 181         /* Information about old entries: */
 182         /* Number of counters (must be equal to current number of entries). */
 183         unsigned int num_counters;
 184         /* The old entries' counters. */
 185         struct xt_counters __user *counters;
 186
 187         /* The entries (hang off end: not really an array). */
 188         struct arpt_entry entries[0];
 189 };
 190
 191 /* The argument to ARPT_SO_ADD_COUNTERS. */
 192 #define arpt_counters_info xt_counters_info
 193 #define arpt_counters xt_counters
 194
 195 /* The argument to ARPT_SO_GET_ENTRIES. */
 196 struct arpt_get_entries
 197 {
 198         /* Which table: user fills this in. */
 199         char name[ARPT_TABLE_MAXNAMELEN];
 200
 201         /* User fills this in: total entry size. */
 202         unsigned int size;
 203
 204         /* The entries. */
 205         struct arpt_entry entrytable[0];
 206 };
 207
 208 /* Standard return verdict, or do jump. */
 209 #define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
 210 /* Error verdict. */
 211 #define ARPT_ERROR_TARGET XT_ERROR_TARGET
 212
 213 /* Helper functions */
 214 static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e)
 215 {
 216         return (void *)e + e->target_offset;
 217 }
 218
 219 /* fn returns 0 to continue iteration */
 220 #define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
 221         XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
 222
 223 /*
 224  *      Main firewall chains definitions and global var's definitions.
 225  */
 226 #ifdef __KERNEL__
 227
 228 /* Standard entry. */
 229 struct arpt_standard
 230 {
 231         struct arpt_entry entry;
 232         struct arpt_standard_target target;
 233 };
 234
 235 struct arpt_error_target
 236 {
 237         struct arpt_entry_target target;
 238         char errorname[ARPT_FUNCTION_MAXNAMELEN];
 239 };
 240
 241 struct arpt_error
 242 {
 243         struct arpt_entry entry;
 244         struct arpt_error_target target;
 245 };
 246
 247 #define ARPT_ENTRY_INIT(__size)                                                \
 248 {                                                                              \
 249         .target_offset  = sizeof(struct arpt_entry),                           \
 250         .next_offset    = (__size),                                            \
 251 }
 252
 253 #define ARPT_STANDARD_INIT(__verdict)                                          \
 254 {                                                                              \
 255         .entry          = ARPT_ENTRY_INIT(sizeof(struct arpt_standard)),       \
 256         .target         = XT_TARGET_INIT(ARPT_STANDARD_TARGET,                 \
 257                                          sizeof(struct arpt_standard_target)), \
 258         .target.verdict = -(__verdict) - 1,                                    \
 259 }
 260
 261 #define ARPT_ERROR_INIT                                                        \
 262 {                                                                              \
 263         .entry          = ARPT_ENTRY_INIT(sizeof(struct arpt_error)),          \
 264         .target         = XT_TARGET_INIT(ARPT_ERROR_TARGET,                    \
 265                                          sizeof(struct arpt_error_target)),    \
 266         .target.errorname = "ERROR",                                           \
 267 }
 268
 269 #define arpt_register_target(tgt)       \
 270 ({      (tgt)->family = NF_ARP;         \
 271         xt_register_target(tgt); })
 272 #define arpt_unregister_target(tgt) xt_unregister_target(tgt)
 273
 274 extern int arpt_register_table(struct arpt_table *table,
 275                                const struct arpt_replace *repl);
 276 extern void arpt_unregister_table(struct arpt_table *table);
 277 extern unsigned int arpt_do_table(struct sk_buff *skb,
 278                                   unsigned int hook,
 279                                   const struct net_device *in,
 280                                   const struct net_device *out,
 281                                   struct arpt_table *table);
 282
 283 #define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1))
 284 #endif /*__KERNEL__*/
 285 #endif /* _ARPTABLES_H */