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/in.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/skbuff.h>
  17 #endif
  18 #include <linux/types.h>
  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
  27 #define ARPT_DEV_ADDR_LEN_MAX 16
  28
  29 struct arpt_devaddr_info {
  30         char addr[ARPT_DEV_ADDR_LEN_MAX];
  31         char mask[ARPT_DEV_ADDR_LEN_MAX];
  32 };
  33
  34 /* Yes, Virginia, you have to zero the padding. */
  35 struct arpt_arp {
  36         /* Source and target IP addr */
  37         struct in_addr src, tgt;
  38         /* Mask for src and target IP addr */
  39         struct in_addr smsk, tmsk;
  40
  41         /* Device hw address length, src+target device addresses */
  42         u_int8_t arhln, arhln_mask;
  43         struct arpt_devaddr_info src_devaddr;
  44         struct arpt_devaddr_info tgt_devaddr;
  45
  46         /* ARP operation code. */
  47         __be16 arpop, arpop_mask;
  48
  49         /* ARP hardware address and protocol address format. */
  50         __be16 arhrd, arhrd_mask;
  51         __be16 arpro, arpro_mask;
  52
  53         /* The protocol address length is only accepted if it is 4
  54          * so there is no use in offering a way to do filtering on it.
  55          */
  56
  57         char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
  58         unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
  59
  60         /* Flags word */
  61         u_int8_t flags;
  62         /* Inverse flags */
  63         u_int16_t invflags;
  64 };
  65
  66 #define arpt_entry_target xt_entry_target
  67 #define arpt_standard_target xt_standard_target
  68
  69 /* Values for "flag" field in struct arpt_ip (general arp structure).
  70  * No flags defined yet.
  71  */
  72 #define ARPT_F_MASK             0x00    /* All possible flag bits mask. */
  73
  74 /* Values for "inv" field in struct arpt_arp. */
  75 #define ARPT_INV_VIA_IN         0x0001  /* Invert the sense of IN IFACE. */
  76 #define ARPT_INV_VIA_OUT        0x0002  /* Invert the sense of OUT IFACE */
  77 #define ARPT_INV_SRCIP          0x0004  /* Invert the sense of SRC IP. */
  78 #define ARPT_INV_TGTIP          0x0008  /* Invert the sense of TGT IP. */
  79 #define ARPT_INV_SRCDEVADDR     0x0010  /* Invert the sense of SRC DEV ADDR. */
  80 #define ARPT_INV_TGTDEVADDR     0x0020  /* Invert the sense of TGT DEV ADDR. */
  81 #define ARPT_INV_ARPOP          0x0040  /* Invert the sense of ARP OP. */
  82 #define ARPT_INV_ARPHRD         0x0080  /* Invert the sense of ARP HRD. */
  83 #define ARPT_INV_ARPPRO         0x0100  /* Invert the sense of ARP PRO. */
  84 #define ARPT_INV_ARPHLN         0x0200  /* Invert the sense of ARP HLN. */
  85 #define ARPT_INV_MASK           0x03FF  /* All possible flag bits mask. */
  86
  87 /* This structure defines each of the firewall rules.  Consists of 3
  88    parts which are 1) general ARP header stuff 2) match specific
  89    stuff 3) the target to perform if the rule matches */
  90 struct arpt_entry
  91 {
  92         struct arpt_arp arp;
  93
  94         /* Size of arpt_entry + matches */
  95         u_int16_t target_offset;
  96         /* Size of arpt_entry + matches + target */
  97         u_int16_t next_offset;
  98
  99         /* Back pointer */
 100         unsigned int comefrom;
 101
 102         /* Packet and byte counters. */
 103         struct xt_counters counters;
 104
 105         /* The matches (if any), then the target. */
 106         unsigned char elems[0];
 107 };
 108
 109 /*
 110  * New IP firewall options for [gs]etsockopt at the RAW IP level.
 111  * Unlike BSD Linux inherits IP options so you don't have to use a raw
 112  * socket for this. Instead we check rights in the calls.
 113  *
 114  * ATTENTION: check linux/in.h before adding new number here.
 115  */
 116 #define ARPT_BASE_CTL           96
 117
 118 #define ARPT_SO_SET_REPLACE             (ARPT_BASE_CTL)
 119 #define ARPT_SO_SET_ADD_COUNTERS        (ARPT_BASE_CTL + 1)
 120 #define ARPT_SO_SET_MAX                 ARPT_SO_SET_ADD_COUNTERS
 121
 122 #define ARPT_SO_GET_INFO                (ARPT_BASE_CTL)
 123 #define ARPT_SO_GET_ENTRIES             (ARPT_BASE_CTL + 1)
 124 /* #define ARPT_SO_GET_REVISION_MATCH   (APRT_BASE_CTL + 2) */
 125 #define ARPT_SO_GET_REVISION_TARGET     (ARPT_BASE_CTL + 3)
 126 #define ARPT_SO_GET_MAX                 (ARPT_SO_GET_REVISION_TARGET)
 127
 128 /* CONTINUE verdict for targets */
 129 #define ARPT_CONTINUE XT_CONTINUE
 130
 131 /* For standard target */
 132 #define ARPT_RETURN XT_RETURN
 133
 134 /* The argument to ARPT_SO_GET_INFO */
 135 struct arpt_getinfo {
 136         /* Which table: caller fills this in. */
 137         char name[ARPT_TABLE_MAXNAMELEN];
 138
 139         /* Kernel fills these in. */
 140         /* Which hook entry points are valid: bitmask */
 141         unsigned int valid_hooks;
 142
 143         /* Hook entry points: one per netfilter hook. */
 144         unsigned int hook_entry[NF_ARP_NUMHOOKS];
 145
 146         /* Underflow points. */
 147         unsigned int underflow[NF_ARP_NUMHOOKS];
 148
 149         /* Number of entries */
 150         unsigned int num_entries;
 151
 152         /* Size of entries. */
 153         unsigned int size;
 154 };
 155
 156 /* The argument to ARPT_SO_SET_REPLACE. */
 157 struct arpt_replace {
 158         /* Which table. */
 159         char name[ARPT_TABLE_MAXNAMELEN];
 160
 161         /* Which hook entry points are valid: bitmask.  You can't
 162            change this. */
 163         unsigned int valid_hooks;
 164
 165         /* Number of entries */
 166         unsigned int num_entries;
 167
 168         /* Total size of new entries */
 169         unsigned int size;
 170
 171         /* Hook entry points. */
 172         unsigned int hook_entry[NF_ARP_NUMHOOKS];
 173
 174         /* Underflow points. */
 175         unsigned int underflow[NF_ARP_NUMHOOKS];
 176
 177         /* Information about old entries: */
 178         /* Number of counters (must be equal to current number of entries). */
 179         unsigned int num_counters;
 180         /* The old entries' counters. */
 181         struct xt_counters __user *counters;
 182
 183         /* The entries (hang off end: not really an array). */
 184         struct arpt_entry entries[0];
 185 };
 186
 187 /* The argument to ARPT_SO_ADD_COUNTERS. */
 188 #define arpt_counters_info xt_counters_info
 189 #define arpt_counters xt_counters
 190
 191 /* The argument to ARPT_SO_GET_ENTRIES. */
 192 struct arpt_get_entries {
 193         /* Which table: user fills this in. */
 194         char name[ARPT_TABLE_MAXNAMELEN];
 195
 196         /* User fills this in: total entry size. */
 197         unsigned int size;
 198
 199         /* The entries. */
 200         struct arpt_entry entrytable[0];
 201 };
 202
 203 /* Standard return verdict, or do jump. */
 204 #define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
 205 /* Error verdict. */
 206 #define ARPT_ERROR_TARGET XT_ERROR_TARGET
 207
 208 /* Helper functions */
 209 static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e)
 210 {
 211         return (void *)e + e->target_offset;
 212 }
 213
 214 /* fn returns 0 to continue iteration */
 215 #define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
 216         XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
 217
 218 /*
 219  *      Main firewall chains definitions and global var's definitions.
 220  */
 221 #ifdef __KERNEL__
 222
 223 /* Standard entry. */
 224 struct arpt_standard {
 225         struct arpt_entry entry;
 226         struct arpt_standard_target target;
 227 };
 228
 229 struct arpt_error_target {
 230         struct arpt_entry_target target;
 231         char errorname[ARPT_FUNCTION_MAXNAMELEN];
 232 };
 233
 234 struct arpt_error {
 235         struct arpt_entry entry;
 236         struct arpt_error_target target;
 237 };
 238
 239 #define ARPT_ENTRY_INIT(__size)                                                \
 240 {                                                                              \
 241         .target_offset  = sizeof(struct arpt_entry),                           \
 242         .next_offset    = (__size),                                            \
 243 }
 244
 245 #define ARPT_STANDARD_INIT(__verdict)                                          \
 246 {                                                                              \
 247         .entry          = ARPT_ENTRY_INIT(sizeof(struct arpt_standard)),       \
 248         .target         = XT_TARGET_INIT(ARPT_STANDARD_TARGET,                 \
 249                                          sizeof(struct arpt_standard_target)), \
 250         .target.verdict = -(__verdict) - 1,                                    \
 251 }
 252
 253 #define ARPT_ERROR_INIT                                                        \
 254 {                                                                              \
 255         .entry          = ARPT_ENTRY_INIT(sizeof(struct arpt_error)),          \
 256         .target         = XT_TARGET_INIT(ARPT_ERROR_TARGET,                    \
 257                                          sizeof(struct arpt_error_target)),    \
 258         .target.errorname = "ERROR",                                           \
 259 }
 260
 261 extern struct xt_table *arpt_register_table(struct net *net,
 262                                             const struct xt_table *table,
 263                                             const struct arpt_replace *repl);
 264 extern void arpt_unregister_table(struct xt_table *table);
 265 extern unsigned int arpt_do_table(struct sk_buff *skb,
 266                                   unsigned int hook,
 267                                   const struct net_device *in,
 268                                   const struct net_device *out,
 269                                   struct xt_table *table);
 270
 271 #define ARPT_ALIGN(s) XT_ALIGN(s)
 272
 273 #ifdef CONFIG_COMPAT
 274 #include <net/compat.h>
 275
 276 struct compat_arpt_entry {
 277         struct arpt_arp arp;
 278         u_int16_t target_offset;
 279         u_int16_t next_offset;
 280         compat_uint_t comefrom;
 281         struct compat_xt_counters counters;
 282         unsigned char elems[0];
 283 };
 284
 285 static inline struct arpt_entry_target *
 286 compat_arpt_get_target(struct compat_arpt_entry *e)
 287 {
 288         return (void *)e + e->target_offset;
 289 }
 290
 291 #define COMPAT_ARPT_ALIGN(s)    COMPAT_XT_ALIGN(s)
 292
 293 /* fn returns 0 to continue iteration */
 294 #define COMPAT_ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
 295         XT_ENTRY_ITERATE(struct compat_arpt_entry, entries, size, fn, ## args)
 296
 297 #define COMPAT_ARPT_ENTRY_ITERATE_CONTINUE(entries, size, n, fn, args...) \
 298         XT_ENTRY_ITERATE_CONTINUE(struct compat_arpt_entry, entries, size, n, \
 299                                   fn, ## args)
 300
 301 #endif /* CONFIG_COMPAT */
 302 #endif /*__KERNEL__*/
 303 #endif /* _ARPTABLES_H */