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 #include <linux/types.h>
13
14 #include <linux/netfilter_arp.h>
15
16 #include <linux/netfilter/x_tables.h>
17
18 #define ARPT_FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
19 #define ARPT_TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
20 #define arpt_entry_target xt_entry_target
21 #define arpt_standard_target xt_standard_target
22 #define arpt_error_target xt_error_target
23 #define ARPT_CONTINUE XT_CONTINUE
24 #define ARPT_RETURN XT_RETURN
25 #define arpt_counters_info xt_counters_info
26 #define arpt_counters xt_counters
27 #define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
28 #define ARPT_ERROR_TARGET XT_ERROR_TARGET
29 #define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
30 XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
31
32 #define ARPT_DEV_ADDR_LEN_MAX 16
33
34 struct arpt_devaddr_info {
35 char addr[ARPT_DEV_ADDR_LEN_MAX];
36 char mask[ARPT_DEV_ADDR_LEN_MAX];
37 };
38
39 /* Yes, Virginia, you have to zero the padding. */
40 struct arpt_arp {
41 /* Source and target IP addr */
42 struct in_addr src, tgt;
43 /* Mask for src and target IP addr */
44 struct in_addr smsk, tmsk;
45
46 /* Device hw address length, src+target device addresses */
47 __u8 arhln, arhln_mask;
48 struct arpt_devaddr_info src_devaddr;
49 struct arpt_devaddr_info tgt_devaddr;
50
51 /* ARP operation code. */
52 __be16 arpop, arpop_mask;
53
54 /* ARP hardware address and protocol address format. */
55 __be16 arhrd, arhrd_mask;
56 __be16 arpro, arpro_mask;
57
58 /* The protocol address length is only accepted if it is 4
59 * so there is no use in offering a way to do filtering on it.
60 */
61
62 char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
63 unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
64
65 /* Flags word */
66 __u8 flags;
67 /* Inverse flags */
68 __u16 invflags;
69 };
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 */
92 struct arpt_entry
93 {
94 struct arpt_arp arp;
95
96 /* Size of arpt_entry + matches */
97 __u16 target_offset;
98 /* Size of arpt_entry + matches + target */
99 __u16 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 * ATTENTION: check linux/in.h before adding new number here.
117 */
118 #define ARPT_BASE_CTL 96
119
120 #define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL)
121 #define ARPT_SO_SET_ADD_COUNTERS (ARPT_BASE_CTL + 1)
122 #define ARPT_SO_SET_MAX ARPT_SO_SET_ADD_COUNTERS
123
124 #define ARPT_SO_GET_INFO (ARPT_BASE_CTL)
125 #define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1)
126 /* #define ARPT_SO_GET_REVISION_MATCH (APRT_BASE_CTL + 2) */
127 #define ARPT_SO_GET_REVISION_TARGET (ARPT_BASE_CTL + 3)
128 #define ARPT_SO_GET_MAX (ARPT_SO_GET_REVISION_TARGET)
129
130 /* The argument to ARPT_SO_GET_INFO */
131 struct arpt_getinfo {
132 /* Which table: caller fills this in. */
133 char name[XT_TABLE_MAXNAMELEN];
134
135 /* Kernel fills these in. */
136 /* Which hook entry points are valid: bitmask */
137 unsigned int valid_hooks;
138
139 /* Hook entry points: one per netfilter hook. */
140 unsigned int hook_entry[NF_ARP_NUMHOOKS];
141
142 /* Underflow points. */
143 unsigned int underflow[NF_ARP_NUMHOOKS];
144
145 /* Number of entries */
146 unsigned int num_entries;
147
148 /* Size of entries. */
149 unsigned int size;
150 };
151
152 /* The argument to ARPT_SO_SET_REPLACE. */
153 struct arpt_replace {
154 /* Which table. */
155 char name[XT_TABLE_MAXNAMELEN];
156
157 /* Which hook entry points are valid: bitmask. You can't
158 change this. */
159 unsigned int valid_hooks;
160
161 /* Number of entries */
162 unsigned int num_entries;
163
164 /* Total size of new entries */
165 unsigned int size;
166
167 /* Hook entry points. */
168 unsigned int hook_entry[NF_ARP_NUMHOOKS];
169
170 /* Underflow points. */
171 unsigned int underflow[NF_ARP_NUMHOOKS];
172
173 /* Information about old entries: */
174 /* Number of counters (must be equal to current number of entries). */
175 unsigned int num_counters;
176 /* The old entries' counters. */
177 struct xt_counters *counters;
178
179 /* The entries (hang off end: not really an array). */
180 struct arpt_entry entries[0];
181 };
182
183 /* The argument to ARPT_SO_GET_ENTRIES. */
184 struct arpt_get_entries {
185 /* Which table: user fills this in. */
186 char name[XT_TABLE_MAXNAMELEN];
187
188 /* User fills this in: total entry size. */
189 unsigned int size;
190
191 /* The entries. */
192 struct arpt_entry entrytable[0];
193 };
194
195 /* Helper functions */
arpt_get_target(struct arpt_entry * e)196 static __inline__ struct xt_entry_target *arpt_get_target(struct arpt_entry *e)
197 {
198 return (void *)e + e->target_offset;
199 }
200
201 /*
202 * Main firewall chains definitions and global var's definitions.
203 */
204 #endif /* _ARPTABLES_H */
205