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 31struct 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. */ 37struct 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 u_int16_t arpop, arpop_mask; 50 51 /* ARP hardware address and protocol address format. */ 52 u_int16_t arhrd, arhrd_mask; 53 u_int16_t 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 */ 92struct 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#define ARPT_CTL_OFFSET 32 117#define ARPT_BASE_CTL (XT_BASE_CTL+ARPT_CTL_OFFSET) 118 119#define ARPT_SO_SET_REPLACE (XT_SO_SET_REPLACE+ARPT_CTL_OFFSET) 120#define ARPT_SO_SET_ADD_COUNTERS (XT_SO_SET_ADD_COUNTERS+ARPT_CTL_OFFSET) 121#define ARPT_SO_SET_MAX (XT_SO_SET_MAX+ARPT_CTL_OFFSET) 122 123#define ARPT_SO_GET_INFO (XT_SO_GET_INFO+ARPT_CTL_OFFSET) 124#define ARPT_SO_GET_ENTRIES (XT_SO_GET_ENTRIES+ARPT_CTL_OFFSET) 125/* #define ARPT_SO_GET_REVISION_MATCH XT_SO_GET_REVISION_MATCH */ 126#define ARPT_SO_GET_REVISION_TARGET (XT_SO_GET_REVISION_TARGET+ARPT_CTL_OFFSET) 127#define ARPT_SO_GET_MAX (XT_SO_GET_REVISION_TARGET+ARPT_CTL_OFFSET) 128 129/* CONTINUE verdict for targets */ 130#define ARPT_CONTINUE XT_CONTINUE 131 132/* For standard target */ 133#define ARPT_RETURN XT_RETURN 134 135/* The argument to ARPT_SO_GET_INFO */ 136struct arpt_getinfo 137{ 138 /* Which table: caller fills this in. */ 139 char name[ARPT_TABLE_MAXNAMELEN]; 140 141 /* Kernel fills these in. */ 142 /* Which hook entry points are valid: bitmask */ 143 unsigned int valid_hooks; 144 145 /* Hook entry points: one per netfilter hook. */ 146 unsigned int hook_entry[NF_ARP_NUMHOOKS]; 147 148 /* Underflow points. */ 149 unsigned int underflow[NF_ARP_NUMHOOKS]; 150 151 /* Number of entries */ 152 unsigned int num_entries; 153 154 /* Size of entries. */ 155 unsigned int size; 156}; 157 158/* The argument to ARPT_SO_SET_REPLACE. */ 159struct arpt_replace 160{ 161 /* Which table. */ 162 char name[ARPT_TABLE_MAXNAMELEN]; 163 164 /* Which hook entry points are valid: bitmask. You can't 165 change this. */ 166 unsigned int valid_hooks; 167 168 /* Number of entries */ 169 unsigned int num_entries; 170 171 /* Total size of new entries */ 172 unsigned int size; 173 174 /* Hook entry points. */ 175 unsigned int hook_entry[NF_ARP_NUMHOOKS]; 176 177 /* Underflow points. */ 178 unsigned int underflow[NF_ARP_NUMHOOKS]; 179 180 /* Information about old entries: */ 181 /* Number of counters (must be equal to current number of entries). */ 182 unsigned int num_counters; 183 /* The old entries' counters. */ 184 struct xt_counters __user *counters; 185 186 /* The entries (hang off end: not really an array). */ 187 struct arpt_entry entries[0]; 188}; 189 190/* The argument to ARPT_SO_ADD_COUNTERS. */ 191#define arpt_counters_info xt_counters_info 192 193/* The argument to ARPT_SO_GET_ENTRIES. */ 194struct arpt_get_entries 195{ 196 /* Which table: user fills this in. */ 197 char name[ARPT_TABLE_MAXNAMELEN]; 198 199 /* User fills this in: total entry size. */ 200 unsigned int size; 201 202 /* The entries. */ 203 struct arpt_entry entrytable[0]; 204}; 205 206/* Standard return verdict, or do jump. */ 207#define ARPT_STANDARD_TARGET XT_STANDARD_TARGET 208/* Error verdict. */ 209#define ARPT_ERROR_TARGET XT_ERROR_TARGET 210 211/* Helper functions */ 212static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e) 213{ 214 return (void *)e + e->target_offset; 215} 216 217/* fn returns 0 to continue iteration */ 218#define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \ 219({ \ 220 unsigned int __i; \ 221 int __ret = 0; \ 222 struct arpt_entry *__entry; \ 223 \ 224 for (__i = 0; __i < (size); __i += __entry->next_offset) { \ 225 __entry = (void *)(entries) + __i; \ 226 \ 227 __ret = fn(__entry , ## args); \ 228 if (__ret != 0) \ 229 break; \ 230 } \ 231 __ret; \ 232}) 233 234/* 235 * Main firewall chains definitions and global var's definitions. 236 */ 237#ifdef __KERNEL__ 238 239#define arpt_register_target(tgt) \ 240({ (tgt)->family = NF_ARP; \ 241 xt_register_target(tgt); }) 242#define arpt_unregister_target(tgt) xt_unregister_target(tgt) 243 244extern int arpt_register_table(struct arpt_table *table, 245 const struct arpt_replace *repl); 246extern void arpt_unregister_table(struct arpt_table *table); 247extern unsigned int arpt_do_table(struct sk_buff **pskb, 248 unsigned int hook, 249 const struct net_device *in, 250 const struct net_device *out, 251 struct arpt_table *table, 252 void *userdata); 253 254#define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1)) 255#endif /*__KERNEL__*/ 256#endif /* _ARPTABLES_H */ 257