1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C)2003-2006 Helsinki University of Technology
4 * Copyright (C)2003-2006 USAGI/WIDE Project
5 */
6 /*
7 * Authors:
8 * Noriaki TAKAMIYA @USAGI
9 * Masahide NAKAMURA @USAGI
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/time.h>
17 #include <linux/ipv6.h>
18 #include <linux/icmpv6.h>
19 #include <net/sock.h>
20 #include <net/ipv6.h>
21 #include <net/ip6_checksum.h>
22 #include <net/rawv6.h>
23 #include <net/xfrm.h>
24 #include <net/mip6.h>
25
26 static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
27 {
28 return (n - len + 16) & 0x7;
29 }
30
31 static inline void *mip6_padn(__u8 *data, __u8 padlen)
32 {
33 if (!data)
34 return NULL;
35 if (padlen == 1) {
36 data[0] = IPV6_TLV_PAD1;
37 } else if (padlen > 1) {
38 data[0] = IPV6_TLV_PADN;
39 data[1] = padlen - 2;
40 if (padlen > 2)
41 memset(data+2, 0, data[1]);
42 }
43 return data + padlen;
44 }
45
46 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
47 {
48 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
49 }
50
51 static int mip6_mh_len(int type)
52 {
53 int len = 0;
54
55 switch (type) {
56 case IP6_MH_TYPE_BRR:
57 len = 0;
58 break;
59 case IP6_MH_TYPE_HOTI:
60 case IP6_MH_TYPE_COTI:
61 case IP6_MH_TYPE_BU:
62 case IP6_MH_TYPE_BACK:
63 len = 1;
64 break;
65 case IP6_MH_TYPE_HOT:
66 case IP6_MH_TYPE_COT:
67 case IP6_MH_TYPE_BERROR:
68 len = 2;
69 break;
70 }
71 return len;
72 }
73
74 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
75 {
76 struct ip6_mh _hdr;
77 const struct ip6_mh *mh;
78
79 mh = skb_header_pointer(skb, skb_transport_offset(skb),
80 sizeof(_hdr), &_hdr);
81 if (!mh)
82 return -1;
83
84 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len)
85 return -1;
86
87 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
88 net_dbg_ratelimited("mip6: MH message too short: %d vs >=%d\n",
89 mh->ip6mh_hdrlen,
90 mip6_mh_len(mh->ip6mh_type));
91 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) +
92 skb_network_header_len(skb));
93 return -1;
94 }
95
96 if (mh->ip6mh_proto != IPPROTO_NONE) {
97 net_dbg_ratelimited("mip6: MH invalid payload proto = %d\n",
98 mh->ip6mh_proto);
99 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) +
100 skb_network_header_len(skb));
101 return -1;
102 }
103
104 return 0;
105 }
106
107 struct mip6_report_rate_limiter {
108 spinlock_t lock;
109 ktime_t stamp;
110 int iif;
111 struct in6_addr src;
112 struct in6_addr dst;
113 };
114
115 static struct mip6_report_rate_limiter mip6_report_rl = {
116 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
117 };
118
119 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
120 {
121 const struct ipv6hdr *iph = ipv6_hdr(skb);
122 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
123 int err = destopt->nexthdr;
124
125 spin_lock(&x->lock);
126 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
127 !ipv6_addr_any((struct in6_addr *)x->coaddr))
128 err = -ENOENT;
129 spin_unlock(&x->lock);
130
131 return err;
132 }
133
134 /* Destination Option Header is inserted.
135 * IP Header's src address is replaced with Home Address Option in
136 * Destination Option Header.
137 */
138 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
139 {
140 struct ipv6hdr *iph;
141 struct ipv6_destopt_hdr *dstopt;
142 struct ipv6_destopt_hao *hao;
143 u8 nexthdr;
144 int len;
145
146 skb_push(skb, -skb_network_offset(skb));
147 iph = ipv6_hdr(skb);
148
149 nexthdr = *skb_mac_header(skb);
150 *skb_mac_header(skb) = IPPROTO_DSTOPTS;
151
152 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
153 dstopt->nexthdr = nexthdr;
154
155 hao = mip6_padn((char *)(dstopt + 1),
156 calc_padlen(sizeof(*dstopt), 6));
157
158 hao->type = IPV6_TLV_HAO;
159 BUILD_BUG_ON(sizeof(*hao) != 18);
160 hao->length = sizeof(*hao) - 2;
161
162 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
163
164 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
165 spin_lock_bh(&x->lock);
166 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
167 spin_unlock_bh(&x->lock);
168
169 WARN_ON(len != x->props.header_len);
170 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
171
172 return 0;
173 }
174
175 static inline int mip6_report_rl_allow(ktime_t stamp,
176 const struct in6_addr *dst,
177 const struct in6_addr *src, int iif)
178 {
179 int allow = 0;
180
181 spin_lock_bh(&mip6_report_rl.lock);
182 if (mip6_report_rl.stamp != stamp ||
183 mip6_report_rl.iif != iif ||
184 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
185 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
186 mip6_report_rl.stamp = stamp;
187 mip6_report_rl.iif = iif;
188 mip6_report_rl.src = *src;
189 mip6_report_rl.dst = *dst;
190 allow = 1;
191 }
192 spin_unlock_bh(&mip6_report_rl.lock);
193 return allow;
194 }
195
196 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
197 const struct flowi *fl)
198 {
199 struct net *net = xs_net(x);
200 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
201 const struct flowi6 *fl6 = &fl->u.ip6;
202 struct ipv6_destopt_hao *hao = NULL;
203 struct xfrm_selector sel;
204 int offset;
205 ktime_t stamp;
206 int err = 0;
207
208 if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
209 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
210 goto out;
211
212 if (likely(opt->dsthao)) {
213 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
214 if (likely(offset >= 0))
215 hao = (struct ipv6_destopt_hao *)
216 (skb_network_header(skb) + offset);
217 }
218
219 stamp = skb_get_ktime(skb);
220
221 if (!mip6_report_rl_allow(stamp, &ipv6_hdr(skb)->daddr,
222 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
223 opt->iif))
224 goto out;
225
226 memset(&sel, 0, sizeof(sel));
227 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
228 sizeof(sel.daddr));
229 sel.prefixlen_d = 128;
230 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
231 sizeof(sel.saddr));
232 sel.prefixlen_s = 128;
233 sel.family = AF_INET6;
234 sel.proto = fl6->flowi6_proto;
235 sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
236 if (sel.dport)
237 sel.dport_mask = htons(~0);
238 sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
239 if (sel.sport)
240 sel.sport_mask = htons(~0);
241 sel.ifindex = fl6->flowi6_oif;
242
243 err = km_report(net, IPPROTO_DSTOPTS, &sel,
244 (hao ? (xfrm_address_t *)&hao->addr : NULL));
245
246 out:
247 return err;
248 }
249
250 static int mip6_destopt_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
251 {
252 if (x->id.spi) {
253 NL_SET_ERR_MSG(extack, "SPI must be 0");
254 return -EINVAL;
255 }
256 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
257 NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION");
258 return -EINVAL;
259 }
260
261 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
262 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
263 sizeof(struct ipv6_destopt_hao);
264 WARN_ON(x->props.header_len != 24);
265
266 return 0;
267 }
268
269 /*
270 * Do nothing about destroying since it has no specific operation for
271 * destination options header unlike IPsec protocols.
272 */
273 static void mip6_destopt_destroy(struct xfrm_state *x)
274 {
275 }
276
277 static const struct xfrm_type mip6_destopt_type = {
278 .owner = THIS_MODULE,
279 .proto = IPPROTO_DSTOPTS,
280 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
281 .init_state = mip6_destopt_init_state,
282 .destructor = mip6_destopt_destroy,
283 .input = mip6_destopt_input,
284 .output = mip6_destopt_output,
285 .reject = mip6_destopt_reject,
286 };
287
288 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
289 {
290 const struct ipv6hdr *iph = ipv6_hdr(skb);
291 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
292 int err = rt2->rt_hdr.nexthdr;
293
294 spin_lock(&x->lock);
295 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
296 !ipv6_addr_any((struct in6_addr *)x->coaddr))
297 err = -ENOENT;
298 spin_unlock(&x->lock);
299
300 return err;
301 }
302
303 /* Routing Header type 2 is inserted.
304 * IP Header's dst address is replaced with Routing Header's Home Address.
305 */
306 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
307 {
308 struct ipv6hdr *iph;
309 struct rt2_hdr *rt2;
310 u8 nexthdr;
311
312 skb_push(skb, -skb_network_offset(skb));
313 iph = ipv6_hdr(skb);
314
315 nexthdr = *skb_mac_header(skb);
316 *skb_mac_header(skb) = IPPROTO_ROUTING;
317
318 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
319 rt2->rt_hdr.nexthdr = nexthdr;
320 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
321 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
322 rt2->rt_hdr.segments_left = 1;
323 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
324
325 WARN_ON(rt2->rt_hdr.hdrlen != 2);
326
327 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
328 spin_lock_bh(&x->lock);
329 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
330 spin_unlock_bh(&x->lock);
331
332 return 0;
333 }
334
335 static int mip6_rthdr_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
336 {
337 if (x->id.spi) {
338 NL_SET_ERR_MSG(extack, "SPI must be 0");
339 return -EINVAL;
340 }
341 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
342 NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION");
343 return -EINVAL;
344 }
345
346 x->props.header_len = sizeof(struct rt2_hdr);
347
348 return 0;
349 }
350
351 /*
352 * Do nothing about destroying since it has no specific operation for routing
353 * header type 2 unlike IPsec protocols.
354 */
355 static void mip6_rthdr_destroy(struct xfrm_state *x)
356 {
357 }
358
359 static const struct xfrm_type mip6_rthdr_type = {
360 .owner = THIS_MODULE,
361 .proto = IPPROTO_ROUTING,
362 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
363 .init_state = mip6_rthdr_init_state,
364 .destructor = mip6_rthdr_destroy,
365 .input = mip6_rthdr_input,
366 .output = mip6_rthdr_output,
367 };
368
369 static int __init mip6_init(void)
370 {
371 pr_info("Mobile IPv6\n");
372
373 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
374 pr_info("%s: can't add xfrm type(destopt)\n", __func__);
375 goto mip6_destopt_xfrm_fail;
376 }
377 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
378 pr_info("%s: can't add xfrm type(rthdr)\n", __func__);
379 goto mip6_rthdr_xfrm_fail;
380 }
381 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
382 pr_info("%s: can't add rawv6 mh filter\n", __func__);
383 goto mip6_rawv6_mh_fail;
384 }
385
386
387 return 0;
388
389 mip6_rawv6_mh_fail:
390 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
391 mip6_rthdr_xfrm_fail:
392 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
393 mip6_destopt_xfrm_fail:
394 return -EAGAIN;
395 }
396
397 static void __exit mip6_fini(void)
398 {
399 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
400 pr_info("%s: can't remove rawv6 mh filter\n", __func__);
401 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
402 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
403 }
404
405 module_init(mip6_init);
406 module_exit(mip6_fini);
407
408 MODULE_DESCRIPTION("IPv6 Mobility driver");
409 MODULE_LICENSE("GPL");
410 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
411 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
412
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