arp_tables.h

  1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
  2/*
  3 * 	Format of an ARP firewall descriptor
  4 *
  5 * 	src, tgt, src_mask, tgt_mask, arpop, arpop_mask are always stored in
  6 *	network byte order.
  7 * 	flags are stored in host byte order (of course).
  8 */
  9
 10#ifndef _UAPI_ARPTABLES_H
 11#define _UAPI_ARPTABLES_H
 12
 13#include <linux/types.h>
 14#include <linux/compiler.h>
 15#include <linux/if.h>
 16#include <linux/netfilter_arp.h>
 17
 18#include <linux/netfilter/x_tables.h>
 19
 20#ifndef __KERNEL__
 21#define ARPT_FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
 22#define ARPT_TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
 23#define arpt_entry_target xt_entry_target
 24#define arpt_standard_target xt_standard_target
 25#define arpt_error_target xt_error_target
 26#define ARPT_CONTINUE XT_CONTINUE
 27#define ARPT_RETURN XT_RETURN
 28#define arpt_counters_info xt_counters_info
 29#define arpt_counters xt_counters
 30#define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
 31#define ARPT_ERROR_TARGET XT_ERROR_TARGET
 32#define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
 33	XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
 34#endif
 35
 36#define ARPT_DEV_ADDR_LEN_MAX 16
 37
 38struct arpt_devaddr_info {
 39	char addr[ARPT_DEV_ADDR_LEN_MAX];
 40	char mask[ARPT_DEV_ADDR_LEN_MAX];
 41};
 42
 43/* Yes, Virginia, you have to zero the padding. */
 44struct arpt_arp {
 45	/* Source and target IP addr */
 46	struct in_addr src, tgt;
 47	/* Mask for src and target IP addr */
 48	struct in_addr smsk, tmsk;
 49
 50	/* Device hw address length, src+target device addresses */
 51	__u8 arhln, arhln_mask;
 52	struct arpt_devaddr_info src_devaddr;
 53	struct arpt_devaddr_info tgt_devaddr;
 54
 55	/* ARP operation code. */
 56	__be16 arpop, arpop_mask;
 57
 58	/* ARP hardware address and protocol address format. */
 59	__be16 arhrd, arhrd_mask;
 60	__be16 arpro, arpro_mask;
 61
 62	/* The protocol address length is only accepted if it is 4
 63	 * so there is no use in offering a way to do filtering on it.
 64	 */
 65
 66	char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
 67	unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
 68
 69	/* Flags word */
 70	__u8 flags;
 71	/* Inverse flags */
 72	__u16 invflags;
 73};
 74
 75/* Values for "flag" field in struct arpt_ip (general arp structure).
 76 * No flags defined yet.
 77 */
 78#define ARPT_F_MASK		0x00	/* All possible flag bits mask. */
 79
 80/* Values for "inv" field in struct arpt_arp. */
 81#define ARPT_INV_VIA_IN		0x0001	/* Invert the sense of IN IFACE. */
 82#define ARPT_INV_VIA_OUT	0x0002	/* Invert the sense of OUT IFACE */
 83#define ARPT_INV_SRCIP		0x0004	/* Invert the sense of SRC IP. */
 84#define ARPT_INV_TGTIP		0x0008	/* Invert the sense of TGT IP. */
 85#define ARPT_INV_SRCDEVADDR	0x0010	/* Invert the sense of SRC DEV ADDR. */
 86#define ARPT_INV_TGTDEVADDR	0x0020	/* Invert the sense of TGT DEV ADDR. */
 87#define ARPT_INV_ARPOP		0x0040	/* Invert the sense of ARP OP. */
 88#define ARPT_INV_ARPHRD		0x0080	/* Invert the sense of ARP HRD. */
 89#define ARPT_INV_ARPPRO		0x0100	/* Invert the sense of ARP PRO. */
 90#define ARPT_INV_ARPHLN		0x0200	/* Invert the sense of ARP HLN. */
 91#define ARPT_INV_MASK		0x03FF	/* All possible flag bits mask. */
 92
 93/* This structure defines each of the firewall rules.  Consists of 3
 94   parts which are 1) general ARP header stuff 2) match specific
 95   stuff 3) the target to perform if the rule matches */
 96struct arpt_entry
 97{
 98	struct arpt_arp arp;
 99
100	/* Size of arpt_entry + matches */
101	__u16 target_offset;
102	/* Size of arpt_entry + matches + target */
103	__u16 next_offset;
104
105	/* Back pointer */
106	unsigned int comefrom;
107
108	/* Packet and byte counters. */
109	struct xt_counters counters;
110
111	/* The matches (if any), then the target. */
112	unsigned char elems[];
113};
114
115/*
116 * New IP firewall options for [gs]etsockopt at the RAW IP level.
117 * Unlike BSD Linux inherits IP options so you don't have to use a raw
118 * socket for this. Instead we check rights in the calls.
119 *
120 * ATTENTION: check linux/in.h before adding new number here.
121 */
122#define ARPT_BASE_CTL		96
123
124#define ARPT_SO_SET_REPLACE		(ARPT_BASE_CTL)
125#define ARPT_SO_SET_ADD_COUNTERS	(ARPT_BASE_CTL + 1)
126#define ARPT_SO_SET_MAX			ARPT_SO_SET_ADD_COUNTERS
127
128#define ARPT_SO_GET_INFO		(ARPT_BASE_CTL)
129#define ARPT_SO_GET_ENTRIES		(ARPT_BASE_CTL + 1)
130/* #define ARPT_SO_GET_REVISION_MATCH	(APRT_BASE_CTL + 2) */
131#define ARPT_SO_GET_REVISION_TARGET	(ARPT_BASE_CTL + 3)
132#define ARPT_SO_GET_MAX			(ARPT_SO_GET_REVISION_TARGET)
133
134/* The argument to ARPT_SO_GET_INFO */
135struct arpt_getinfo {
136	/* Which table: caller fills this in. */
137	char name[XT_TABLE_MAXNAMELEN];
138
139	/* Kernel fills these in. */
140	/* Which hook entry points are valid: bitmask */
141	unsigned int valid_hooks;
142
143	/* Hook entry points: one per netfilter hook. */
144	unsigned int hook_entry[NF_ARP_NUMHOOKS];
145
146	/* Underflow points. */
147	unsigned int underflow[NF_ARP_NUMHOOKS];
148
149	/* Number of entries */
150	unsigned int num_entries;
151
152	/* Size of entries. */
153	unsigned int size;
154};
155
156/* The argument to ARPT_SO_SET_REPLACE. */
157struct arpt_replace {
158	/* Which table. */
159	char name[XT_TABLE_MAXNAMELEN];
160
161	/* Which hook entry points are valid: bitmask.  You can't
162           change this. */
163	unsigned int valid_hooks;
164
165	/* Number of entries */
166	unsigned int num_entries;
167
168	/* Total size of new entries */
169	unsigned int size;
170
171	/* Hook entry points. */
172	unsigned int hook_entry[NF_ARP_NUMHOOKS];
173
174	/* Underflow points. */
175	unsigned int underflow[NF_ARP_NUMHOOKS];
176
177	/* Information about old entries: */
178	/* Number of counters (must be equal to current number of entries). */
179	unsigned int num_counters;
180	/* The old entries' counters. */
181	struct xt_counters __user *counters;
182
183	/* The entries (hang off end: not really an array). */
184	struct arpt_entry entries[];
185};
186
187/* The argument to ARPT_SO_GET_ENTRIES. */
188struct arpt_get_entries {
189	/* Which table: user fills this in. */
190	char name[XT_TABLE_MAXNAMELEN];
191
192	/* User fills this in: total entry size. */
193	unsigned int size;
194
195	/* The entries. */
196	struct arpt_entry entrytable[];
197};
198
199/* Helper functions */
200static __inline__ struct xt_entry_target *arpt_get_target(struct arpt_entry *e)
201{
202	return (struct xt_entry_target *)((char *)e + e->target_offset);
203}
204
205/*
206 *	Main firewall chains definitions and global var's definitions.
207 */
208#endif /* _UAPI_ARPTABLES_H */