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