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/*
* 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/types.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#endif
#include <linux/netfilter_arp.h>
#define ARPT_FUNCTION_MAXNAMELEN 30
#define ARPT_TABLE_MAXNAMELEN 32
#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 */
u_int8_t arhln, arhln_mask;
struct arpt_devaddr_info src_devaddr;
struct arpt_devaddr_info tgt_devaddr;
/* ARP operation code. */
u_int16_t arpop, arpop_mask;
/* ARP hardware address and protocol address format. */
u_int16_t arhrd, arhrd_mask;
u_int16_t 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 */
u_int8_t flags;
/* Inverse flags */
u_int16_t invflags;
};
struct arpt_entry_target
{
union {
struct {
u_int16_t target_size;
/* Used by userspace */
char name[ARPT_FUNCTION_MAXNAMELEN];
} user;
struct {
u_int16_t target_size;
/* Used inside the kernel */
struct arpt_target *target;
} kernel;
/* Total length */
u_int16_t target_size;
} u;
unsigned char data[0];
};
struct arpt_standard_target
{
struct arpt_entry_target target;
int verdict;
};
struct arpt_counters
{
u_int64_t pcnt, bcnt; /* Packet and byte counters */
};
/* 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 */
u_int16_t target_offset;
/* Size of arpt_entry + matches + target */
u_int16_t next_offset;
/* Back pointer */
unsigned int comefrom;
/* Packet and byte counters. */
struct arpt_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.
*/
#define ARPT_BASE_CTL 96 /* base for firewall socket options */
#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_MAX ARPT_SO_GET_ENTRIES
/* CONTINUE verdict for targets */
#define ARPT_CONTINUE 0xFFFFFFFF
/* For standard target */
#define ARPT_RETURN (-NF_MAX_VERDICT - 1)
/* The argument to ARPT_SO_GET_INFO */
struct arpt_getinfo
{
/* Which table: caller fills this in. */
char name[ARPT_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[ARPT_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 arpt_counters *counters;
/* The entries (hang off end: not really an array). */
struct arpt_entry entries[0];
};
/* The argument to ARPT_SO_ADD_COUNTERS. */
struct arpt_counters_info
{
/* Which table. */
char name[ARPT_TABLE_MAXNAMELEN];
unsigned int num_counters;
/* The counters (actually `number' of these). */
struct arpt_counters counters[0];
};
/* The argument to ARPT_SO_GET_ENTRIES. */
struct arpt_get_entries
{
/* Which table: user fills this in. */
char name[ARPT_TABLE_MAXNAMELEN];
/* User fills this in: total entry size. */
unsigned int size;
/* The entries. */
struct arpt_entry entrytable[0];
};
/* Standard return verdict, or do jump. */
#define ARPT_STANDARD_TARGET ""
/* Error verdict. */
#define ARPT_ERROR_TARGET "ERROR"
/* Helper functions */
static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e)
{
return (void *)e + e->target_offset;
}
/* fn returns 0 to continue iteration */
#define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
({ \
unsigned int __i; \
int __ret = 0; \
struct arpt_entry *__entry; \
\
for (__i = 0; __i < (size); __i += __entry->next_offset) { \
__entry = (void *)(entries) + __i; \
\
__ret = fn(__entry , ## args); \
if (__ret != 0) \
break; \
} \
__ret; \
})
/*
* Main firewall chains definitions and global var's definitions.
*/
#ifdef __KERNEL__
/* Registration hooks for targets. */
struct arpt_target
{
struct list_head list;
const char name[ARPT_FUNCTION_MAXNAMELEN];
/* Returns verdict. */
unsigned int (*target)(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo,
void *userdata);
/* Called when user tries to insert an entry of this type:
hook_mask is a bitmask of hooks from which it can be
called. */
/* Should return true or false. */
int (*checkentry)(const char *tablename,
const struct arpt_entry *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask);
/* Called when entry of this type deleted. */
void (*destroy)(void *targinfo, unsigned int targinfosize);
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
};
extern int arpt_register_target(struct arpt_target *target);
extern void arpt_unregister_target(struct arpt_target *target);
/* Furniture shopping... */
struct arpt_table
{
struct list_head list;
/* A unique name... */
char name[ARPT_TABLE_MAXNAMELEN];
/* Seed table: copied in register_table */
struct arpt_replace *table;
/* What hooks you will enter on */
unsigned int valid_hooks;
/* Lock for the curtain */
rwlock_t lock;
/* Man behind the curtain... */
struct arpt_table_info *private;
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
};
extern int arpt_register_table(struct arpt_table *table);
extern void arpt_unregister_table(struct arpt_table *table);
extern unsigned int arpt_do_table(struct sk_buff **pskb,
unsigned int hook,
const struct net_device *in,
const struct net_device *out,
struct arpt_table *table,
void *userdata);
#define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1))
#endif /*__KERNEL__*/
#endif /* _ARPTABLES_H */