rthdr.c revision 330897 
1/*	$KAME: rthdr.c,v 1.19 2003/06/06 10:48:51 itojun Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: stable/11/lib/libc/net/rthdr.c 330897 2018-03-14 03:19:51Z eadler $");
36
37#include <sys/param.h>
38#include <sys/socket.h>
39
40#include <netinet/in.h>
41#include <netinet/ip6.h>
42
43#include <string.h>
44#include <stdio.h>
45
46/*
47 * RFC2292 API
48 */
49
50size_t
51inet6_rthdr_space(int type, int seg)
52{
53	switch (type) {
54	case IPV6_RTHDR_TYPE_0:
55		if (seg < 1 || seg > 23)
56			return (0);
57#ifdef COMPAT_RFC2292
58		return (CMSG_SPACE(sizeof(struct in6_addr) * (seg - 1) +
59		    sizeof(struct ip6_rthdr0)));
60#else
61		return (CMSG_SPACE(sizeof(struct in6_addr) * seg +
62		    sizeof(struct ip6_rthdr0)));
63#endif
64	default:
65		return (0);
66	}
67}
68
69struct cmsghdr *
70inet6_rthdr_init(void *bp, int type)
71{
72	struct cmsghdr *ch = (struct cmsghdr *)bp;
73	struct ip6_rthdr *rthdr;
74
75	rthdr = (struct ip6_rthdr *)CMSG_DATA(ch);
76
77	ch->cmsg_level = IPPROTO_IPV6;
78	ch->cmsg_type = IPV6_RTHDR;
79
80	switch (type) {
81	case IPV6_RTHDR_TYPE_0:
82#ifdef COMPAT_RFC2292
83		ch->cmsg_len = CMSG_LEN(sizeof(struct ip6_rthdr0) -
84		    sizeof(struct in6_addr));
85#else
86		ch->cmsg_len = CMSG_LEN(sizeof(struct ip6_rthdr0));
87#endif
88
89		bzero(rthdr, sizeof(struct ip6_rthdr0));
90		rthdr->ip6r_type = IPV6_RTHDR_TYPE_0;
91		return (ch);
92	default:
93		return (NULL);
94	}
95}
96
97/* ARGSUSED */
98int
99inet6_rthdr_add(struct cmsghdr *cmsg, const struct in6_addr *addr, u_int flags)
100{
101	struct ip6_rthdr *rthdr;
102
103	rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
104
105	switch (rthdr->ip6r_type) {
106	case IPV6_RTHDR_TYPE_0:
107	{
108		struct ip6_rthdr0 *rt0 = (struct ip6_rthdr0 *)rthdr;
109		if (flags != IPV6_RTHDR_LOOSE && flags != IPV6_RTHDR_STRICT)
110			return (-1);
111		if (rt0->ip6r0_segleft == 23)
112			return (-1);
113
114#ifdef COMPAT_RFC1883		/* XXX */
115		if (flags == IPV6_RTHDR_STRICT) {
116			int c, b;
117			c = rt0->ip6r0_segleft / 8;
118			b = rt0->ip6r0_segleft % 8;
119			rt0->ip6r0_slmap[c] |= (1 << (7 - b));
120		}
121#else
122		if (flags != IPV6_RTHDR_LOOSE)
123			return (-1);
124#endif
125		rt0->ip6r0_segleft++;
126		bcopy(addr, (caddr_t)rt0 + ((rt0->ip6r0_len + 1) << 3),
127		    sizeof(struct in6_addr));
128		rt0->ip6r0_len += sizeof(struct in6_addr) >> 3;
129		cmsg->cmsg_len = CMSG_LEN((rt0->ip6r0_len + 1) << 3);
130		break;
131	}
132	default:
133		return (-1);
134	}
135
136	return (0);
137}
138
139/* ARGSUSED */
140int
141inet6_rthdr_lasthop(struct cmsghdr *cmsg, unsigned int flags)
142{
143	struct ip6_rthdr *rthdr;
144
145	rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
146
147	switch (rthdr->ip6r_type) {
148	case IPV6_RTHDR_TYPE_0:
149	{
150		struct ip6_rthdr0 *rt0 = (struct ip6_rthdr0 *)rthdr;
151#ifdef COMPAT_RFC1883		/* XXX */
152		if (flags != IPV6_RTHDR_LOOSE && flags != IPV6_RTHDR_STRICT)
153			return (-1);
154#endif /* COMPAT_RFC1883 */
155		if (rt0->ip6r0_segleft > 23)
156			return (-1);
157#ifdef COMPAT_RFC1883		/* XXX */
158		if (flags == IPV6_RTHDR_STRICT) {
159			int c, b;
160			c = rt0->ip6r0_segleft / 8;
161			b = rt0->ip6r0_segleft % 8;
162			rt0->ip6r0_slmap[c] |= (1 << (7 - b));
163		}
164#else
165		if (flags != IPV6_RTHDR_LOOSE)
166			return (-1);
167#endif /* COMPAT_RFC1883 */
168		break;
169	}
170	default:
171		return (-1);
172	}
173
174	return (0);
175}
176
177#if 0
178int
179inet6_rthdr_reverse(const struct cmsghdr *in, struct cmsghdr *out)
180{
181
182	return (-1);
183}
184#endif
185
186int
187inet6_rthdr_segments(const struct cmsghdr *cmsg)
188{
189	struct ip6_rthdr *rthdr;
190
191	rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
192
193	switch (rthdr->ip6r_type) {
194	case IPV6_RTHDR_TYPE_0:
195	{
196		struct ip6_rthdr0 *rt0 = (struct ip6_rthdr0 *)rthdr;
197
198		if (rt0->ip6r0_len % 2 || 46 < rt0->ip6r0_len)
199			return (-1);
200
201		return (rt0->ip6r0_len * 8) / sizeof(struct in6_addr);
202	}
203
204	default:
205		return (-1);
206	}
207}
208
209struct in6_addr *
210inet6_rthdr_getaddr(struct cmsghdr *cmsg, int idx)
211{
212	struct ip6_rthdr *rthdr;
213
214	rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
215
216	switch (rthdr->ip6r_type) {
217	case IPV6_RTHDR_TYPE_0:
218	{
219		struct ip6_rthdr0 *rt0 = (struct ip6_rthdr0 *)rthdr;
220		int naddr;
221
222		if (rt0->ip6r0_len % 2 || 46 < rt0->ip6r0_len)
223			return NULL;
224		naddr = (rt0->ip6r0_len * 8) / sizeof(struct in6_addr);
225		if (idx <= 0 || naddr < idx)
226			return NULL;
227#ifdef COMPAT_RFC2292
228		return (((struct in6_addr *)(rt0 + 1)) + idx - 1);
229#else
230		return (((struct in6_addr *)(rt0 + 1)) + idx);
231#endif
232	}
233
234	default:
235		return NULL;
236	}
237}
238
239int
240inet6_rthdr_getflags(const struct cmsghdr *cmsg, int idx)
241{
242	struct ip6_rthdr *rthdr;
243
244	rthdr = (struct ip6_rthdr *)CMSG_DATA(cmsg);
245
246	switch (rthdr->ip6r_type) {
247	case IPV6_RTHDR_TYPE_0:
248	{
249		struct ip6_rthdr0 *rt0 = (struct ip6_rthdr0 *)rthdr;
250		int naddr;
251
252		if (rt0->ip6r0_len % 2 || 46 < rt0->ip6r0_len)
253			return (-1);
254		naddr = (rt0->ip6r0_len * 8) / sizeof(struct in6_addr);
255		if (idx < 0 || naddr < idx)
256			return (-1);
257#ifdef COMPAT_RFC1883		/* XXX */
258		if (rt0->ip6r0_slmap[idx / 8] & (0x80 >> (idx % 8)))
259			return IPV6_RTHDR_STRICT;
260		else
261			return IPV6_RTHDR_LOOSE;
262#else
263		return IPV6_RTHDR_LOOSE;
264#endif /* COMPAT_RFC1883 */
265	}
266
267	default:
268		return (-1);
269	}
270}
271
272/*
273 * RFC3542 API
274 */
275
276socklen_t
277inet6_rth_space(int type, int segments)
278{
279	switch (type) {
280	case IPV6_RTHDR_TYPE_0:
281		if ((segments >= 0) && (segments <= 127))
282			return (((segments * 2) + 1) << 3);
283		/* FALLTHROUGH */
284	default:
285		return (0);	/* type not suppported */
286	}
287}
288
289void *
290inet6_rth_init(void *bp, socklen_t bp_len, int type, int segments)
291{
292	struct ip6_rthdr *rth = (struct ip6_rthdr *)bp;
293	struct ip6_rthdr0 *rth0;
294
295	switch (type) {
296	case IPV6_RTHDR_TYPE_0:
297		/* length validation */
298		if (bp_len < inet6_rth_space(IPV6_RTHDR_TYPE_0, segments))
299			return (NULL);
300		/* segment validation */
301		if ((segments < 0) || (segments > 127))
302			return (NULL);
303
304		memset(bp, 0, bp_len);
305		rth0 = (struct ip6_rthdr0 *)rth;
306		rth0->ip6r0_len = segments * 2;
307		rth0->ip6r0_type = IPV6_RTHDR_TYPE_0;
308		rth0->ip6r0_segleft = 0;
309		rth0->ip6r0_reserved = 0;
310		break;
311	default:
312		return (NULL);	/* type not supported */
313	}
314
315	return (bp);
316}
317
318int
319inet6_rth_add(void *bp, const struct in6_addr *addr)
320{
321	struct ip6_rthdr *rth = (struct ip6_rthdr *)bp;
322	struct ip6_rthdr0 *rth0;
323	struct in6_addr *nextaddr;
324
325	switch (rth->ip6r_type) {
326	case IPV6_RTHDR_TYPE_0:
327		rth0 = (struct ip6_rthdr0 *)rth;
328		/* Don't exceed the number of stated segments */
329		if (rth0->ip6r0_segleft == (rth0->ip6r0_len / 2))
330			return (-1);
331		nextaddr = (struct in6_addr *)(rth0 + 1) + rth0->ip6r0_segleft;
332		*nextaddr = *addr;
333		rth0->ip6r0_segleft++;
334		break;
335	default:
336		return (-1);	/* type not supported */
337	}
338
339	return (0);
340}
341
342int
343inet6_rth_reverse(const void *in, void *out)
344{
345	struct ip6_rthdr *rth_in = (struct ip6_rthdr *)in;
346	struct ip6_rthdr0 *rth0_in, *rth0_out;
347	int i, segments;
348
349	switch (rth_in->ip6r_type) {
350	case IPV6_RTHDR_TYPE_0:
351		rth0_in = (struct ip6_rthdr0 *)in;
352		rth0_out = (struct ip6_rthdr0 *)out;
353
354		/* parameter validation XXX too paranoid? */
355		if (rth0_in->ip6r0_len % 2)
356			return (-1);
357		segments = rth0_in->ip6r0_len / 2;
358
359		/* we can't use memcpy here, since in and out may overlap */
360		memmove((void *)rth0_out, (void *)rth0_in,
361			((rth0_in->ip6r0_len) + 1) << 3);
362		rth0_out->ip6r0_segleft = segments;
363
364		/* reverse the addresses */
365		for (i = 0; i < segments / 2; i++) {
366			struct in6_addr addr_tmp, *addr1, *addr2;
367
368			addr1 = (struct in6_addr *)(rth0_out + 1) + i;
369			addr2 = (struct in6_addr *)(rth0_out + 1) +
370				(segments - i - 1);
371			addr_tmp = *addr1;
372			*addr1 = *addr2;
373			*addr2 = addr_tmp;
374		}
375
376		break;
377	default:
378		return (-1);	/* type not supported */
379	}
380
381	return (0);
382}
383
384int
385inet6_rth_segments(const void *bp)
386{
387	struct ip6_rthdr *rh = (struct ip6_rthdr *)bp;
388	struct ip6_rthdr0 *rh0;
389	int addrs;
390
391	switch (rh->ip6r_type) {
392	case IPV6_RTHDR_TYPE_0:
393		rh0 = (struct ip6_rthdr0 *)bp;
394
395		/*
396		 * Validation for a type-0 routing header.
397		 * Is this too strict?
398		 */
399		if ((rh0->ip6r0_len % 2) != 0 ||
400		    (addrs = (rh0->ip6r0_len >> 1)) < rh0->ip6r0_segleft)
401			return (-1);
402
403		return (addrs);
404	default:
405		return (-1);	/* unknown type */
406	}
407}
408
409struct in6_addr *
410inet6_rth_getaddr(const void *bp, int idx)
411{
412	struct ip6_rthdr *rh = (struct ip6_rthdr *)bp;
413	struct ip6_rthdr0 *rh0;
414	int addrs;
415
416	switch (rh->ip6r_type) {
417	case IPV6_RTHDR_TYPE_0:
418		 rh0 = (struct ip6_rthdr0 *)bp;
419
420		/*
421		 * Validation for a type-0 routing header.
422		 * Is this too strict?
423		 */
424		if ((rh0->ip6r0_len % 2) != 0 ||
425		    (addrs = (rh0->ip6r0_len >> 1)) < rh0->ip6r0_segleft)
426			return (NULL);
427
428		if (idx < 0 || addrs <= idx)
429			return (NULL);
430
431		return (((struct in6_addr *)(rh0 + 1)) + idx);
432	default:
433		return (NULL);	/* unknown type */
434		break;
435	}
436}
437