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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
19#include <linux/netfilter/x_tables.h>
20#include <linux/netfilter_ipv6/ip6_tables.h>
21#include <linux/netfilter_ipv6/ip6t_rt.h>
22
23MODULE_LICENSE("GPL");
24MODULE_DESCRIPTION("Xtables: IPv6 Routing Header match");
25MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
26
27
28static inline bool
29segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
30{
31 bool r;
32 pr_debug("rt segsleft_match:%c 0x%x <= 0x%x <= 0x%x",
33 invert ? '!' : ' ', min, id, max);
34 r = (id >= min && id <= max) ^ invert;
35 pr_debug(" result %s\n", r ? "PASS" : "FAILED");
36 return r;
37}
38
39static bool rt_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
40{
41 struct ipv6_rt_hdr _route;
42 const struct ipv6_rt_hdr *rh;
43 const struct ip6t_rt *rtinfo = par->matchinfo;
44 unsigned int temp;
45 unsigned int ptr;
46 unsigned int hdrlen = 0;
47 bool ret = false;
48 struct in6_addr _addr;
49 const struct in6_addr *ap;
50 int err;
51
52 err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL);
53 if (err < 0) {
54 if (err != -ENOENT)
55 *par->hotdrop = true;
56 return false;
57 }
58
59 rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
60 if (rh == NULL) {
61 *par->hotdrop = true;
62 return false;
63 }
64
65 hdrlen = ipv6_optlen(rh);
66 if (skb->len - ptr < hdrlen) {
67
68 return false;
69 }
70
71 pr_debug("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen);
72 pr_debug("TYPE %04X ", rh->type);
73 pr_debug("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left);
74
75 pr_debug("IPv6 RT segsleft %02X ",
76 segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
77 rh->segments_left,
78 !!(rtinfo->invflags & IP6T_RT_INV_SGS)));
79 pr_debug("type %02X %02X %02X ",
80 rtinfo->rt_type, rh->type,
81 (!(rtinfo->flags & IP6T_RT_TYP) ||
82 ((rtinfo->rt_type == rh->type) ^
83 !!(rtinfo->invflags & IP6T_RT_INV_TYP))));
84 pr_debug("len %02X %04X %02X ",
85 rtinfo->hdrlen, hdrlen,
86 !(rtinfo->flags & IP6T_RT_LEN) ||
87 ((rtinfo->hdrlen == hdrlen) ^
88 !!(rtinfo->invflags & IP6T_RT_INV_LEN)));
89 pr_debug("res %02X %02X %02X ",
90 rtinfo->flags & IP6T_RT_RES,
91 ((const struct rt0_hdr *)rh)->reserved,
92 !((rtinfo->flags & IP6T_RT_RES) &&
93 (((const struct rt0_hdr *)rh)->reserved)));
94
95 ret = (rh != NULL)
96 &&
97 (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
98 rh->segments_left,
99 !!(rtinfo->invflags & IP6T_RT_INV_SGS)))
100 &&
101 (!(rtinfo->flags & IP6T_RT_LEN) ||
102 ((rtinfo->hdrlen == hdrlen) ^
103 !!(rtinfo->invflags & IP6T_RT_INV_LEN)))
104 &&
105 (!(rtinfo->flags & IP6T_RT_TYP) ||
106 ((rtinfo->rt_type == rh->type) ^
107 !!(rtinfo->invflags & IP6T_RT_INV_TYP)));
108
109 if (ret && (rtinfo->flags & IP6T_RT_RES)) {
110 const u_int32_t *rp;
111 u_int32_t _reserved;
112 rp = skb_header_pointer(skb,
113 ptr + offsetof(struct rt0_hdr,
114 reserved),
115 sizeof(_reserved),
116 &_reserved);
117
118 ret = (*rp == 0);
119 }
120
121 pr_debug("#%d ", rtinfo->addrnr);
122 if (!(rtinfo->flags & IP6T_RT_FST)) {
123 return ret;
124 } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
125 pr_debug("Not strict ");
126 if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
127 pr_debug("There isn't enough space\n");
128 return false;
129 } else {
130 unsigned int i = 0;
131
132 pr_debug("#%d ", rtinfo->addrnr);
133 for (temp = 0;
134 temp < (unsigned int)((hdrlen - 8) / 16);
135 temp++) {
136 ap = skb_header_pointer(skb,
137 ptr
138 + sizeof(struct rt0_hdr)
139 + temp * sizeof(_addr),
140 sizeof(_addr),
141 &_addr);
142
143 BUG_ON(ap == NULL);
144
145 if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
146 pr_debug("i=%d temp=%d;\n", i, temp);
147 i++;
148 }
149 if (i == rtinfo->addrnr)
150 break;
151 }
152 pr_debug("i=%d #%d\n", i, rtinfo->addrnr);
153 if (i == rtinfo->addrnr)
154 return ret;
155 else
156 return false;
157 }
158 } else {
159 pr_debug("Strict ");
160 if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
161 pr_debug("There isn't enough space\n");
162 return false;
163 } else {
164 pr_debug("#%d ", rtinfo->addrnr);
165 for (temp = 0; temp < rtinfo->addrnr; temp++) {
166 ap = skb_header_pointer(skb,
167 ptr
168 + sizeof(struct rt0_hdr)
169 + temp * sizeof(_addr),
170 sizeof(_addr),
171 &_addr);
172 BUG_ON(ap == NULL);
173
174 if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
175 break;
176 }
177 pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr);
178 if (temp == rtinfo->addrnr &&
179 temp == (unsigned int)((hdrlen - 8) / 16))
180 return ret;
181 else
182 return false;
183 }
184 }
185
186 return false;
187}
188
189static bool rt_mt6_check(const struct xt_mtchk_param *par)
190{
191 const struct ip6t_rt *rtinfo = par->matchinfo;
192
193 if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
194 pr_debug("ip6t_rt: unknown flags %X\n", rtinfo->invflags);
195 return false;
196 }
197 if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
198 (!(rtinfo->flags & IP6T_RT_TYP) ||
199 (rtinfo->rt_type != 0) ||
200 (rtinfo->invflags & IP6T_RT_INV_TYP))) {
201 pr_debug("`--rt-type 0' required before `--rt-0-*'");
202 return false;
203 }
204
205 return true;
206}
207
208static struct xt_match rt_mt6_reg __read_mostly = {
209 .name = "rt",
210 .family = NFPROTO_IPV6,
211 .match = rt_mt6,
212 .matchsize = sizeof(struct ip6t_rt),
213 .checkentry = rt_mt6_check,
214 .me = THIS_MODULE,
215};
216
217static int __init rt_mt6_init(void)
218{
219 return xt_register_match(&rt_mt6_reg);
220}
221
222static void __exit rt_mt6_exit(void)
223{
224 xt_unregister_match(&rt_mt6_reg);
225}
226
227module_init(rt_mt6_init);
228module_exit(rt_mt6_exit);
229
