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 #ifdef __KERNEL__
13 #include <linux/if.h>
14 #include <linux/in.h>
15 #include <linux/if_arp.h>
16 #include <linux/skbuff.h>
17 #endif
18 #include <linux/types.h>
19 #include <linux/compiler.h>
20 #include <linux/netfilter_arp.h>
21
22 #include <linux/netfilter/x_tables.h>
23
24 #ifndef __KERNEL__
25 #define ARPT_FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
26 #define ARPT_TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
27 #define arpt_entry_target xt_entry_target
28 #define arpt_standard_target xt_standard_target
29 #define arpt_error_target xt_error_target
30 #define ARPT_CONTINUE XT_CONTINUE
31 #define ARPT_RETURN XT_RETURN
32 #define arpt_counters_info xt_counters_info
33 #define arpt_counters xt_counters
34 #define ARPT_STANDARD_TARGET XT_STANDARD_TARGET
35 #define ARPT_ERROR_TARGET XT_ERROR_TARGET
36 #define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \
37 XT_ENTRY_ITERATE(struct arpt_entry, entries, size, fn, ## args)
38 #endif
39
40 #define ARPT_DEV_ADDR_LEN_MAX 16
41
42 struct arpt_devaddr_info {
43 char addr[ARPT_DEV_ADDR_LEN_MAX];
44 char mask[ARPT_DEV_ADDR_LEN_MAX];
45 };
46
47 /* Yes, Virginia, you have to zero the padding. */
48 struct arpt_arp {
49 /* Source and target IP addr */
50 struct in_addr src, tgt;
51 /* Mask for src and target IP addr */
52 struct in_addr smsk, tmsk;
53
54 /* Device hw address length, src+target device addresses */
55 __u8 arhln, arhln_mask;
56 struct arpt_devaddr_info src_devaddr;
57 struct arpt_devaddr_info tgt_devaddr;
58
59 /* ARP operation code. */
60 __be16 arpop, arpop_mask;
61
62 /* ARP hardware address and protocol address format. */
63 __be16 arhrd, arhrd_mask;
64 __be16 arpro, arpro_mask;
65
66 /* The protocol address length is only accepted if it is 4
67 * so there is no use in offering a way to do filtering on it.
68 */
69
70 char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
71 unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
72
73 /* Flags word */
74 __u8 flags;
75 /* Inverse flags */
76 __u16 invflags;
77 };
78
79 /* Values for "flag" field in struct arpt_ip (general arp structure).
80 * No flags defined yet.
81 */
82 #define ARPT_F_MASK 0x00 /* All possible flag bits mask. */
83
84 /* Values for "inv" field in struct arpt_arp. */
85 #define ARPT_INV_VIA_IN 0x0001 /* Invert the sense of IN IFACE. */
86 #define ARPT_INV_VIA_OUT 0x0002 /* Invert the sense of OUT IFACE */
87 #define ARPT_INV_SRCIP 0x0004 /* Invert the sense of SRC IP. */
88 #define ARPT_INV_TGTIP 0x0008 /* Invert the sense of TGT IP. */
89 #define ARPT_INV_SRCDEVADDR 0x0010 /* Invert the sense of SRC DEV ADDR. */
90 #define ARPT_INV_TGTDEVADDR 0x0020 /* Invert the sense of TGT DEV ADDR. */
91 #define ARPT_INV_ARPOP 0x0040 /* Invert the sense of ARP OP. */
92 #define ARPT_INV_ARPHRD 0x0080 /* Invert the sense of ARP HRD. */
93 #define ARPT_INV_ARPPRO 0x0100 /* Invert the sense of ARP PRO. */
94 #define ARPT_INV_ARPHLN 0x0200 /* Invert the sense of ARP HLN. */
95 #define ARPT_INV_MASK 0x03FF /* All possible flag bits mask. */
96
97 /* This structure defines each of the firewall rules. Consists of 3
98 parts which are 1) general ARP header stuff 2) match specific
99 stuff 3) the target to perform if the rule matches */
100 struct arpt_entry
101 {
102 struct arpt_arp arp;
103
104 /* Size of arpt_entry + matches */
105 __u16 target_offset;
106 /* Size of arpt_entry + matches + target */
107 __u16 next_offset;
108
109 /* Back pointer */
110 unsigned int comefrom;
111
112 /* Packet and byte counters. */
113 struct xt_counters counters;
114
115 /* The matches (if any), then the target. */
116 unsigned char elems[0];
117 };
118
119 /*
120 * New IP firewall options for [gs]etsockopt at the RAW IP level.
121 * Unlike BSD Linux inherits IP options so you don't have to use a raw
122 * socket for this. Instead we check rights in the calls.
123 *
124 * ATTENTION: check linux/in.h before adding new number here.
125 */
126 #define ARPT_BASE_CTL 96
127
128 #define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL)
129 #define ARPT_SO_SET_ADD_COUNTERS (ARPT_BASE_CTL + 1)
130 #define ARPT_SO_SET_MAX ARPT_SO_SET_ADD_COUNTERS
131
132 #define ARPT_SO_GET_INFO (ARPT_BASE_CTL)
133 #define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1)
134 /* #define ARPT_SO_GET_REVISION_MATCH (APRT_BASE_CTL + 2) */
135 #define ARPT_SO_GET_REVISION_TARGET (ARPT_BASE_CTL + 3)
136 #define ARPT_SO_GET_MAX (ARPT_SO_GET_REVISION_TARGET)
137
138 /* The argument to ARPT_SO_GET_INFO */
139 struct arpt_getinfo {
140 /* Which table: caller fills this in. */
141 char name[XT_TABLE_MAXNAMELEN];
142
143 /* Kernel fills these in. */
144 /* Which hook entry points are valid: bitmask */
145 unsigned int valid_hooks;
146
147 /* Hook entry points: one per netfilter hook. */
148 unsigned int hook_entry[NF_ARP_NUMHOOKS];
149
150 /* Underflow points. */
151 unsigned int underflow[NF_ARP_NUMHOOKS];
152
153 /* Number of entries */
154 unsigned int num_entries;
155
156 /* Size of entries. */
157 unsigned int size;
158 };
159
160 /* The argument to ARPT_SO_SET_REPLACE. */
161 struct arpt_replace {
162 /* Which table. */
163 char name[XT_TABLE_MAXNAMELEN];
164
165 /* Which hook entry points are valid: bitmask. You can't
166 change this. */
167 unsigned int valid_hooks;
168
169 /* Number of entries */
170 unsigned int num_entries;
171
172 /* Total size of new entries */
173 unsigned int size;
174
175 /* Hook entry points. */
176 unsigned int hook_entry[NF_ARP_NUMHOOKS];
177
178 /* Underflow points. */
179 unsigned int underflow[NF_ARP_NUMHOOKS];
180
181 /* Information about old entries: */
182 /* Number of counters (must be equal to current number of entries). */
183 unsigned int num_counters;
184 /* The old entries' counters. */
185 struct xt_counters __user *counters;
186
187 /* The entries (hang off end: not really an array). */
188 struct arpt_entry entries[0];
189 };
190
191 /* The argument to ARPT_SO_GET_ENTRIES. */
192 struct arpt_get_entries {
193 /* Which table: user fills this in. */
194 char name[XT_TABLE_MAXNAMELEN];
195
196 /* User fills this in: total entry size. */
197 unsigned int size;
198
199 /* The entries. */
200 struct arpt_entry entrytable[0];
201 };
202
203 /* Helper functions */
arpt_get_target(struct arpt_entry * e)204 static __inline__ struct xt_entry_target *arpt_get_target(struct arpt_entry *e)
205 {
206 return (void *)e + e->target_offset;
207 }
208
209 /*
210 * Main firewall chains definitions and global var's definitions.
211 */
212 #ifdef __KERNEL__
213
214 /* Standard entry. */
215 struct arpt_standard {
216 struct arpt_entry entry;
217 struct xt_standard_target target;
218 };
219
220 struct arpt_error {
221 struct arpt_entry entry;
222 struct xt_error_target target;
223 };
224
225 #define ARPT_ENTRY_INIT(__size) \
226 { \
227 .target_offset = sizeof(struct arpt_entry), \
228 .next_offset = (__size), \
229 }
230
231 #define ARPT_STANDARD_INIT(__verdict) \
232 { \
233 .entry = ARPT_ENTRY_INIT(sizeof(struct arpt_standard)), \
234 .target = XT_TARGET_INIT(XT_STANDARD_TARGET, \
235 sizeof(struct xt_standard_target)), \
236 .target.verdict = -(__verdict) - 1, \
237 }
238
239 #define ARPT_ERROR_INIT \
240 { \
241 .entry = ARPT_ENTRY_INIT(sizeof(struct arpt_error)), \
242 .target = XT_TARGET_INIT(XT_ERROR_TARGET, \
243 sizeof(struct xt_error_target)), \
244 .target.errorname = "ERROR", \
245 }
246
247 extern void *arpt_alloc_initial_table(const struct xt_table *);
248 extern struct xt_table *arpt_register_table(struct net *net,
249 const struct xt_table *table,
250 const struct arpt_replace *repl);
251 extern void arpt_unregister_table(struct xt_table *table);
252 extern unsigned int arpt_do_table(struct sk_buff *skb,
253 unsigned int hook,
254 const struct net_device *in,
255 const struct net_device *out,
256 struct xt_table *table);
257
258 #ifdef CONFIG_COMPAT
259 #include <net/compat.h>
260
261 struct compat_arpt_entry {
262 struct arpt_arp arp;
263 __u16 target_offset;
264 __u16 next_offset;
265 compat_uint_t comefrom;
266 struct compat_xt_counters counters;
267 unsigned char elems[0];
268 };
269
270 static inline struct xt_entry_target *
compat_arpt_get_target(struct compat_arpt_entry * e)271 compat_arpt_get_target(struct compat_arpt_entry *e)
272 {
273 return (void *)e + e->target_offset;
274 }
275
276 #endif /* CONFIG_COMPAT */
277 #endif /*__KERNEL__*/
278 #endif /* _ARPTABLES_H */
279