Subversion Repositories shark

/*

 *      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 */