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Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module to match ROUTING parameters. */ |
2 | ||
3 | /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/ipv6.h> | |
13 | #include <linux/types.h> | |
14 | #include <net/checksum.h> | |
15 | #include <net/ipv6.h> | |
16 | ||
17 | #include <asm/byteorder.h> | |
18 | ||
6709dbbb | 19 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
20 | #include <linux/netfilter_ipv6/ip6_tables.h> |
21 | #include <linux/netfilter_ipv6/ip6t_rt.h> | |
22 | ||
23 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 24 | MODULE_DESCRIPTION("Xtables: IPv6 Routing Header match"); |
1da177e4 LT |
25 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
26 | ||
1da177e4 | 27 | /* Returns 1 if the id is matched by the range, 0 otherwise */ |
1d93a9cb JE |
28 | static inline bool |
29 | segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert) | |
1da177e4 | 30 | { |
1d93a9cb | 31 | bool r; |
0d53778e PM |
32 | pr_debug("rt segsleft_match:%c 0x%x <= 0x%x <= 0x%x", |
33 | invert ? '!' : ' ', min, id, max); | |
f0daaa65 | 34 | r = (id >= min && id <= max) ^ invert; |
0d53778e | 35 | pr_debug(" result %s\n", r ? "PASS" : "FAILED"); |
f0daaa65 | 36 | return r; |
1da177e4 LT |
37 | } |
38 | ||
1d93a9cb | 39 | static bool |
d3c5ee6d JE |
40 | rt_mt6(const struct sk_buff *skb, const struct net_device *in, |
41 | const struct net_device *out, const struct xt_match *match, | |
42 | const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop) | |
1da177e4 | 43 | { |
a47362a2 JE |
44 | struct ipv6_rt_hdr _route; |
45 | const struct ipv6_rt_hdr *rh; | |
f0daaa65 YK |
46 | const struct ip6t_rt *rtinfo = matchinfo; |
47 | unsigned int temp; | |
48 | unsigned int ptr; | |
49 | unsigned int hdrlen = 0; | |
1d93a9cb | 50 | bool ret = false; |
a47362a2 JE |
51 | struct in6_addr _addr; |
52 | const struct in6_addr *ap; | |
6d381634 | 53 | int err; |
1da177e4 | 54 | |
6d381634 PM |
55 | err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL); |
56 | if (err < 0) { | |
57 | if (err != -ENOENT) | |
cff533ac | 58 | *hotdrop = true; |
1d93a9cb | 59 | return false; |
6d381634 | 60 | } |
1da177e4 | 61 | |
f0daaa65 YK |
62 | rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route); |
63 | if (rh == NULL) { | |
cff533ac | 64 | *hotdrop = true; |
1d93a9cb | 65 | return false; |
f0daaa65 YK |
66 | } |
67 | ||
68 | hdrlen = ipv6_optlen(rh); | |
69 | if (skb->len - ptr < hdrlen) { | |
70 | /* Pcket smaller than its length field */ | |
1d93a9cb | 71 | return false; |
f0daaa65 YK |
72 | } |
73 | ||
0d53778e PM |
74 | pr_debug("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen); |
75 | pr_debug("TYPE %04X ", rh->type); | |
76 | pr_debug("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left); | |
77 | ||
78 | pr_debug("IPv6 RT segsleft %02X ", | |
79 | segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], | |
80 | rh->segments_left, | |
81 | !!(rtinfo->invflags & IP6T_RT_INV_SGS))); | |
82 | pr_debug("type %02X %02X %02X ", | |
83 | rtinfo->rt_type, rh->type, | |
84 | (!(rtinfo->flags & IP6T_RT_TYP) || | |
85 | ((rtinfo->rt_type == rh->type) ^ | |
86 | !!(rtinfo->invflags & IP6T_RT_INV_TYP)))); | |
87 | pr_debug("len %02X %04X %02X ", | |
88 | rtinfo->hdrlen, hdrlen, | |
89 | !(rtinfo->flags & IP6T_RT_LEN) || | |
90 | ((rtinfo->hdrlen == hdrlen) ^ | |
91 | !!(rtinfo->invflags & IP6T_RT_INV_LEN))); | |
92 | pr_debug("res %02X %02X %02X ", | |
93 | rtinfo->flags & IP6T_RT_RES, | |
94 | ((const struct rt0_hdr *)rh)->reserved, | |
95 | !((rtinfo->flags & IP6T_RT_RES) && | |
96 | (((const struct rt0_hdr *)rh)->reserved))); | |
f0daaa65 YK |
97 | |
98 | ret = (rh != NULL) | |
99 | && | |
100 | (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], | |
101 | rh->segments_left, | |
102 | !!(rtinfo->invflags & IP6T_RT_INV_SGS))) | |
103 | && | |
104 | (!(rtinfo->flags & IP6T_RT_LEN) || | |
105 | ((rtinfo->hdrlen == hdrlen) ^ | |
106 | !!(rtinfo->invflags & IP6T_RT_INV_LEN))) | |
107 | && | |
108 | (!(rtinfo->flags & IP6T_RT_TYP) || | |
109 | ((rtinfo->rt_type == rh->type) ^ | |
110 | !!(rtinfo->invflags & IP6T_RT_INV_TYP))); | |
1da177e4 LT |
111 | |
112 | if (ret && (rtinfo->flags & IP6T_RT_RES)) { | |
e6df439b BH |
113 | u_int32_t *rp, _reserved; |
114 | rp = skb_header_pointer(skb, | |
f0daaa65 YK |
115 | ptr + offsetof(struct rt0_hdr, |
116 | reserved), | |
117 | sizeof(_reserved), | |
118 | &_reserved); | |
1da177e4 | 119 | |
e6df439b | 120 | ret = (*rp == 0); |
1da177e4 LT |
121 | } |
122 | ||
0d53778e | 123 | pr_debug("#%d ", rtinfo->addrnr); |
f0daaa65 YK |
124 | if (!(rtinfo->flags & IP6T_RT_FST)) { |
125 | return ret; | |
1da177e4 | 126 | } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) { |
0d53778e | 127 | pr_debug("Not strict "); |
f0daaa65 | 128 | if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) { |
0d53778e | 129 | pr_debug("There isn't enough space\n"); |
1d93a9cb | 130 | return false; |
1da177e4 LT |
131 | } else { |
132 | unsigned int i = 0; | |
133 | ||
0d53778e | 134 | pr_debug("#%d ", rtinfo->addrnr); |
f0daaa65 YK |
135 | for (temp = 0; |
136 | temp < (unsigned int)((hdrlen - 8) / 16); | |
137 | temp++) { | |
1da177e4 LT |
138 | ap = skb_header_pointer(skb, |
139 | ptr | |
140 | + sizeof(struct rt0_hdr) | |
141 | + temp * sizeof(_addr), | |
142 | sizeof(_addr), | |
143 | &_addr); | |
144 | ||
145 | BUG_ON(ap == NULL); | |
146 | ||
147 | if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) { | |
0d53778e | 148 | pr_debug("i=%d temp=%d;\n", i, temp); |
1da177e4 LT |
149 | i++; |
150 | } | |
f0daaa65 YK |
151 | if (i == rtinfo->addrnr) |
152 | break; | |
1da177e4 | 153 | } |
0d53778e | 154 | pr_debug("i=%d #%d\n", i, rtinfo->addrnr); |
1da177e4 LT |
155 | if (i == rtinfo->addrnr) |
156 | return ret; | |
f0daaa65 | 157 | else |
1d93a9cb | 158 | return false; |
1da177e4 LT |
159 | } |
160 | } else { | |
0d53778e | 161 | pr_debug("Strict "); |
f0daaa65 | 162 | if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) { |
0d53778e | 163 | pr_debug("There isn't enough space\n"); |
1d93a9cb | 164 | return false; |
1da177e4 | 165 | } else { |
0d53778e | 166 | pr_debug("#%d ", rtinfo->addrnr); |
f0daaa65 | 167 | for (temp = 0; temp < rtinfo->addrnr; temp++) { |
1da177e4 LT |
168 | ap = skb_header_pointer(skb, |
169 | ptr | |
170 | + sizeof(struct rt0_hdr) | |
171 | + temp * sizeof(_addr), | |
172 | sizeof(_addr), | |
173 | &_addr); | |
174 | BUG_ON(ap == NULL); | |
175 | ||
176 | if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp])) | |
177 | break; | |
178 | } | |
0d53778e | 179 | pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr); |
7c4e36bc JE |
180 | if (temp == rtinfo->addrnr && |
181 | temp == (unsigned int)((hdrlen - 8) / 16)) | |
1da177e4 | 182 | return ret; |
f0daaa65 | 183 | else |
1d93a9cb | 184 | return false; |
1da177e4 LT |
185 | } |
186 | } | |
187 | ||
1d93a9cb | 188 | return false; |
1da177e4 LT |
189 | } |
190 | ||
191 | /* Called when user tries to insert an entry of this type. */ | |
ccb79bdc | 192 | static bool |
d3c5ee6d JE |
193 | rt_mt6_check(const char *tablename, const void *entry, |
194 | const struct xt_match *match, void *matchinfo, | |
195 | unsigned int hook_mask) | |
1da177e4 | 196 | { |
f0daaa65 YK |
197 | const struct ip6t_rt *rtinfo = matchinfo; |
198 | ||
f0daaa65 | 199 | if (rtinfo->invflags & ~IP6T_RT_INV_MASK) { |
0d53778e | 200 | pr_debug("ip6t_rt: unknown flags %X\n", rtinfo->invflags); |
ccb79bdc | 201 | return false; |
f0daaa65 YK |
202 | } |
203 | if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) && | |
204 | (!(rtinfo->flags & IP6T_RT_TYP) || | |
205 | (rtinfo->rt_type != 0) || | |
206 | (rtinfo->invflags & IP6T_RT_INV_TYP))) { | |
0d53778e | 207 | pr_debug("`--rt-type 0' required before `--rt-0-*'"); |
ccb79bdc | 208 | return false; |
f0daaa65 YK |
209 | } |
210 | ||
ccb79bdc | 211 | return true; |
1da177e4 LT |
212 | } |
213 | ||
d3c5ee6d | 214 | static struct xt_match rt_mt6_reg __read_mostly = { |
1da177e4 | 215 | .name = "rt", |
6709dbbb | 216 | .family = AF_INET6, |
d3c5ee6d | 217 | .match = rt_mt6, |
7f939713 | 218 | .matchsize = sizeof(struct ip6t_rt), |
d3c5ee6d | 219 | .checkentry = rt_mt6_check, |
1da177e4 LT |
220 | .me = THIS_MODULE, |
221 | }; | |
222 | ||
d3c5ee6d | 223 | static int __init rt_mt6_init(void) |
1da177e4 | 224 | { |
d3c5ee6d | 225 | return xt_register_match(&rt_mt6_reg); |
1da177e4 LT |
226 | } |
227 | ||
d3c5ee6d | 228 | static void __exit rt_mt6_exit(void) |
1da177e4 | 229 | { |
d3c5ee6d | 230 | xt_unregister_match(&rt_mt6_reg); |
1da177e4 LT |
231 | } |
232 | ||
d3c5ee6d JE |
233 | module_init(rt_mt6_init); |
234 | module_exit(rt_mt6_exit); |