arp_tables.h
/*
* Format of an ARP firewall descriptor
*
* src, tgt, src_mask, tgt_mask, arpop, arpop_mask are always stored in
* network byte order.
* flags are stored in host byte order (of course).
*/
#ifndef _ARPTABLES_H
#define _ARPTABLES_H
#ifdef __KERNEL__
#include <linux/if.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#endif
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/netfilter_arp.h>
#include <linux/netfilter/x_tables.h>
#ifndef __KERNEL__
#define ARPT_FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
#define ARPT_TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
#define arpt_entry_target xt_entry_target
#define arpt_standard_target xt_standard_target
#define arpt_error_target xt_error_target
#define ARPT_CONTINUE XT_CONTINUE
#define ARPT_RETURN XT_RETURN
#define arpt_counters_info xt_counters_info
#define arpt_counters xt_counters
#define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
#define ARPT_ERROR_TARGET XT_ERROR_TARGET
#define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
#endif
#define ARPT_DEV_ADDR_LEN_MAX 16
struct arpt_devaddr_info {
char addr[ARPT_DEV_ADDR_LEN_MAX];
char mask[ARPT_DEV_ADDR_LEN_MAX];
};
/* Yes, Virginia, you have to zero the padding. */
struct arpt_arp {
/* Source and target IP addr */
struct in_addr src, tgt;
/* Mask for src and target IP addr */
struct in_addr smsk, tmsk;
/* Device hw address length, src+target device addresses */
__u8 arhln, arhln_mask;
struct arpt_devaddr_info src_devaddr;
struct arpt_devaddr_info tgt_devaddr;
/* ARP operation code. */
__be16 arpop, arpop_mask;
/* ARP hardware address and protocol address format. */
__be16 arhrd, arhrd_mask;
__be16 arpro, arpro_mask;
/* The protocol address length is only accepted if it is 4
* so there is no use in offering a way to do filtering on it.
*/
char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
/* Flags word */
__u8 flags;
/* Inverse flags */
__u16 invflags;
};
/* Values for "flag" field in struct arpt_ip (general arp structure).
* No flags defined yet.
*/
#define ARPT_F_MASK 0x00 /* All possible flag bits mask. */
/* Values for "inv" field in struct arpt_arp. */
#define ARPT_INV_VIA_IN 0x0001 /* Invert the sense of IN IFACE. */
#define ARPT_INV_VIA_OUT 0x0002 /* Invert the sense of OUT IFACE */
#define ARPT_INV_SRCIP 0x0004 /* Invert the sense of SRC IP. */
#define ARPT_INV_TGTIP 0x0008 /* Invert the sense of TGT IP. */
#define ARPT_INV_SRCDEVADDR 0x0010 /* Invert the sense of SRC DEV ADDR. */
#define ARPT_INV_TGTDEVADDR 0x0020 /* Invert the sense of TGT DEV ADDR. */
#define ARPT_INV_ARPOP 0x0040 /* Invert the sense of ARP OP. */
#define ARPT_INV_ARPHRD 0x0080 /* Invert the sense of ARP HRD. */
#define ARPT_INV_ARPPRO 0x0100 /* Invert the sense of ARP PRO. */
#define ARPT_INV_ARPHLN 0x0200 /* Invert the sense of ARP HLN. */
#define ARPT_INV_MASK 0x03FF /* All possible flag bits mask. */
/* This structure defines each of the firewall rules. Consists of 3
parts which are 1) general ARP header stuff 2) match specific
stuff 3) the target to perform if the rule matches */
struct arpt_entry
{
struct arpt_arp arp;
/* Size of arpt_entry + matches */
__u16 target_offset;
/* Size of arpt_entry + matches + target */
__u16 next_offset;
/* Back pointer */
unsigned int comefrom;
/* Packet and byte counters. */
struct xt_counters counters;
/* The matches (if any), then the target. */
unsigned char elems[0];
};
/*
* New IP firewall options for [gs]etsockopt at the RAW IP level.
* Unlike BSD Linux inherits IP options so you don't have to use a raw
* socket for this. Instead we check rights in the calls.
*
* ATTENTION: check linux/in.h before adding new number here.
*/
#define ARPT_BASE_CTL 96
#define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL)
#define ARPT_SO_SET_ADD_COUNTERS (ARPT_BASE_CTL + 1)
#define ARPT_SO_SET_MAX ARPT_SO_SET_ADD_COUNTERS
#define ARPT_SO_GET_INFO (ARPT_BASE_CTL)
#define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1)
/* #define ARPT_SO_GET_REVISION_MATCH (APRT_BASE_CTL + 2) */
#define ARPT_SO_GET_REVISION_TARGET (ARPT_BASE_CTL + 3)
#define ARPT_SO_GET_MAX (ARPT_SO_GET_REVISION_TARGET)
/* The argument to ARPT_SO_GET_INFO */
struct arpt_getinfo {
/* Which table: caller fills this in. */
char name[XT_TABLE_MAXNAMELEN];
/* Kernel fills these in. */
/* Which hook entry points are valid: bitmask */
unsigned int valid_hooks;
/* Hook entry points: one per netfilter hook. */
unsigned int hook_entry[NF_ARP_NUMHOOKS];
/* Underflow points. */
unsigned int underflow[NF_ARP_NUMHOOKS];
/* Number of entries */
unsigned int num_entries;
/* Size of entries. */
unsigned int size;
};
/* The argument to ARPT_SO_SET_REPLACE. */
struct arpt_replace {
/* Which table. */
char name[XT_TABLE_MAXNAMELEN];
/* Which hook entry points are valid: bitmask. You can't
change this. */
unsigned int valid_hooks;
/* Number of entries */
unsigned int num_entries;
/* Total size of new entries */
unsigned int size;
/* Hook entry points. */
unsigned int hook_entry[NF_ARP_NUMHOOKS];
/* Underflow points. */
unsigned int underflow[NF_ARP_NUMHOOKS];
/* Information about old entries: */
/* Number of counters (must be equal to current number of entries). */
unsigned int num_counters;
/* The old entries' counters. */
struct xt_counters __user *counters;
/* The entries (hang off end: not really an array). */
struct arpt_entry entries[0];
};
/* The argument to ARPT_SO_GET_ENTRIES. */
struct arpt_get_entries {
/* Which table: user fills this in. */
char name[XT_TABLE_MAXNAMELEN];
/* User fills this in: total entry size. */
unsigned int size;
/* The entries. */
struct arpt_entry entrytable[0];
};
/* Helper functions */
static __inline__ struct xt_entry_target *arpt_get_target(struct arpt_entry *e)
{
return (void *)e + e->target_offset;
}
/*
* Main firewall chains definitions and global var's definitions.
*/
#ifdef __KERNEL__
/* Standard entry. */
struct arpt_standard {
struct arpt_entry entry;
struct xt_standard_target target;
};
struct arpt_error {
struct arpt_entry entry;
struct xt_error_target target;
};
#define ARPT_ENTRY_INIT(__size) \
{ \
.target_offset = sizeof(struct arpt_entry), \
.next_offset = (__size), \
}
#define ARPT_STANDARD_INIT(__verdict) \
{ \
.entry = ARPT_ENTRY_INIT(sizeof(struct arpt_standard)), \
.target = XT_TARGET_INIT(XT_STANDARD_TARGET, \
sizeof(struct xt_standard_target)), \
.target.verdict = -(__verdict) - 1, \
}
#define ARPT_ERROR_INIT \
{ \
.entry = ARPT_ENTRY_INIT(sizeof(struct arpt_error)), \
.target = XT_TARGET_INIT(XT_ERROR_TARGET, \
sizeof(struct xt_error_target)), \
.target.errorname = "ERROR", \
}
extern void *arpt_alloc_initial_table(const struct xt_table *);
extern struct xt_table *arpt_register_table(struct net *net,
const struct xt_table *table,
const struct arpt_replace *repl);
extern void arpt_unregister_table(struct xt_table *table);
extern unsigned int arpt_do_table(struct sk_buff *skb,
unsigned int hook,
const struct net_device *in,
const struct net_device *out,
struct xt_table *table);
#ifdef CONFIG_COMPAT
#include <net/compat.h>
struct compat_arpt_entry {
struct arpt_arp arp;
__u16 target_offset;
__u16 next_offset;
compat_uint_t comefrom;
struct compat_xt_counters counters;
unsigned char elems[0];
};
static inline struct xt_entry_target *
compat_arpt_get_target(struct compat_arpt_entry *e)
{
return (void *)e + e->target_offset;
}
#endif /* CONFIG_COMPAT */
#endif /*__KERNEL__*/
#endif /* _ARPTABLES_H */