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9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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("segsleft_match:%c 0x%x <= 0x%x <= 0x%x\n",
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, struct xt_action_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 (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
97 rh->segments_left,
98 !!(rtinfo->invflags & IP6T_RT_INV_SGS))) &&
99 (!(rtinfo->flags & IP6T_RT_LEN) ||
100 ((rtinfo->hdrlen == hdrlen) ^
101 !!(rtinfo->invflags & IP6T_RT_INV_LEN))) &&
102 (!(rtinfo->flags & IP6T_RT_TYP) ||
103 ((rtinfo->rt_type == rh->type) ^
104 !!(rtinfo->invflags & IP6T_RT_INV_TYP)));
105
106 if (ret && (rtinfo->flags & IP6T_RT_RES)) {
107 const u_int32_t *rp;
108 u_int32_t _reserved;
109 rp = skb_header_pointer(skb,
110 ptr + offsetof(struct rt0_hdr,
111 reserved),
112 sizeof(_reserved),
113 &_reserved);
114
115 ret = (*rp == 0);
116 }
117
118 pr_debug("#%d ", rtinfo->addrnr);
119 if (!(rtinfo->flags & IP6T_RT_FST)) {
120 return ret;
121 } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
122 pr_debug("Not strict ");
123 if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
124 pr_debug("There isn't enough space\n");
125 return false;
126 } else {
127 unsigned int i = 0;
128
129 pr_debug("#%d ", rtinfo->addrnr);
130 for (temp = 0;
131 temp < (unsigned int)((hdrlen - 8) / 16);
132 temp++) {
133 ap = skb_header_pointer(skb,
134 ptr
135 + sizeof(struct rt0_hdr)
136 + temp * sizeof(_addr),
137 sizeof(_addr),
138 &_addr);
139
140 BUG_ON(ap == NULL);
141
142 if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
143 pr_debug("i=%d temp=%d;\n", i, temp);
144 i++;
145 }
146 if (i == rtinfo->addrnr)
147 break;
148 }
149 pr_debug("i=%d #%d\n", i, rtinfo->addrnr);
150 if (i == rtinfo->addrnr)
151 return ret;
152 else
153 return false;
154 }
155 } else {
156 pr_debug("Strict ");
157 if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
158 pr_debug("There isn't enough space\n");
159 return false;
160 } else {
161 pr_debug("#%d ", rtinfo->addrnr);
162 for (temp = 0; temp < rtinfo->addrnr; temp++) {
163 ap = skb_header_pointer(skb,
164 ptr
165 + sizeof(struct rt0_hdr)
166 + temp * sizeof(_addr),
167 sizeof(_addr),
168 &_addr);
169 BUG_ON(ap == NULL);
170
171 if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
172 break;
173 }
174 pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr);
175 if (temp == rtinfo->addrnr &&
176 temp == (unsigned int)((hdrlen - 8) / 16))
177 return ret;
178 else
179 return false;
180 }
181 }
182
183 return false;
184}
185
186static int rt_mt6_check(const struct xt_mtchk_param *par)
187{
188 const struct ip6t_rt *rtinfo = par->matchinfo;
189
190 if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
191 pr_debug("unknown flags %X\n", rtinfo->invflags);
192 return -EINVAL;
193 }
194 if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
195 (!(rtinfo->flags & IP6T_RT_TYP) ||
196 (rtinfo->rt_type != 0) ||
197 (rtinfo->invflags & IP6T_RT_INV_TYP))) {
198 pr_debug("`--rt-type 0' required before `--rt-0-*'");
199 return -EINVAL;
200 }
201
202 return 0;
203}
204
205static struct xt_match rt_mt6_reg __read_mostly = {
206 .name = "rt",
207 .family = NFPROTO_IPV6,
208 .match = rt_mt6,
209 .matchsize = sizeof(struct ip6t_rt),
210 .checkentry = rt_mt6_check,
211 .me = THIS_MODULE,
212};
213
214static int __init rt_mt6_init(void)
215{
216 return xt_register_match(&rt_mt6_reg);
217}
218
219static void __exit rt_mt6_exit(void)
220{
221 xt_unregister_match(&rt_mt6_reg);
222}
223
224module_init(rt_mt6_init);
225module_exit(rt_mt6_exit);
226
