1/*	$NetBSD: if.c,v 1.29 2021/03/23 18:16:53 christos Exp $	*/
2/*	$KAME: if.c,v 1.36 2004/11/30 22:32:01 suz Exp $	*/
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#define RTM_NAMES
34#include <sys/param.h>
35#include <sys/queue.h>
36#include <sys/socket.h>
37#include <sys/sysctl.h>
38#include <sys/ioctl.h>
39#include <net/if.h>
40#include <net/if_types.h>
41#include <ifaddrs.h>
42#ifdef __FreeBSD__
43#include <net/ethernet.h>
44#else
45#include <net/if_ether.h>
46#endif
47#include <net/route.h>
48#include <net/if_dl.h>
49#include <netinet/in.h>
50#include <netinet/icmp6.h>
51#include <unistd.h>
52#include <errno.h>
53#include <stdlib.h>
54#include <string.h>
55#include <syslog.h>
56
57#include "rtadvd.h"
58#include "if.h"
59#include "logit.h"
60#include "prog_ops.h"
61
62#ifndef RT_ROUNDUP
63#define RT_ROUNDUP(a)							       \
64	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
65#define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
66#endif
67
68static void
69get_rtaddrs(int addrs, const struct sockaddr *sa,
70    const struct sockaddr **rti_info)
71{
72	int i;
73
74	for (i = 0; i < RTAX_MAX; i++) {
75		if (addrs & (1 << i)) {
76			rti_info[i] = sa;
77			RT_ADVANCE(sa, sa);
78		}
79		else
80			rti_info[i] = NULL;
81	}
82}
83
84struct sockaddr_dl *
85if_nametosdl(const char *name)
86{
87	struct ifaddrs *ifap, *ifa;
88	struct sockaddr_dl *sdl;
89
90	if (getifaddrs(&ifap) != 0)
91		return (NULL);
92
93	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
94		if (strcmp(ifa->ifa_name, name) != 0)
95			continue;
96		if (ifa->ifa_addr->sa_family != AF_LINK)
97			continue;
98
99		sdl = malloc(ifa->ifa_addr->sa_len);
100		if (!sdl)
101			continue;	/*XXX*/
102
103		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
104		freeifaddrs(ifap);
105		return (sdl);
106	}
107
108	freeifaddrs(ifap);
109	return (NULL);
110}
111
112int
113if_getmtu(const char *name)
114{
115	struct ifreq ifr;
116	int s, mtu;
117
118	if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
119		return 0;
120
121	memset(&ifr, 0, sizeof(ifr));
122	ifr.ifr_addr.sa_family = AF_INET6;
123	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
124	if (prog_ioctl(s, SIOCGIFMTU, &ifr) != -1)
125		mtu = ifr.ifr_mtu;
126	else
127		mtu = 0;
128	prog_close(s);
129
130	return mtu;
131}
132
133/* give interface index and its old flags, then new flags returned */
134int
135if_getflags(unsigned int ifindex, int oifflags)
136{
137	struct ifreq ifr;
138	int s;
139
140	if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
141		logit(LOG_ERR, "%s: socket: %m", __func__);
142		return (oifflags & ~IFF_UP);
143	}
144
145	memset(&ifr, 0, sizeof(ifr));
146	if_indextoname(ifindex, ifr.ifr_name);
147	if (prog_ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
148		logit(LOG_ERR, "%s: ioctl:SIOCGIFFLAGS: failed for %s",
149		       __func__, ifr.ifr_name);
150		prog_close(s);
151		return (oifflags & ~IFF_UP);
152	}
153	prog_close(s);
154	return (ifr.ifr_flags);
155}
156
157#define ROUNDUP8(a) (1 + (((a) - 1) | 7))
158int
159lladdropt_length(struct sockaddr_dl *sdl)
160{
161	switch (sdl->sdl_type) {
162	case IFT_ETHER:
163	case IFT_FDDI:
164		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
165	default:
166		return(0);
167	}
168}
169
170void
171lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
172{
173	char *addr;
174
175	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
176
177	switch (sdl->sdl_type) {
178	case IFT_ETHER:
179	case IFT_FDDI:
180		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
181		addr = (char *)(ndopt + 1);
182		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
183		break;
184	default:
185		logit(LOG_ERR, "%s: unsupported link type(%d)",
186		    __func__, sdl->sdl_type);
187		exit(1);
188	}
189
190	return;
191}
192
193#define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
194#define SIN6(s) ((const struct sockaddr_in6 *)(s))
195#define SDL(s) ((const struct sockaddr_dl *)(s))
196char *
197get_next_msg(char *buf, char *lim, unsigned int ifindex, size_t *lenp,
198    int filter)
199{
200	struct rt_msghdr *rtm;
201	struct ifa_msghdr *ifam;
202	const struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
203
204	*lenp = 0;
205	for (rtm = (struct rt_msghdr *)buf;
206	     rtm < (struct rt_msghdr *)lim;
207	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
208		/* just for safety */
209		if (!rtm->rtm_msglen) {
210			logit(LOG_WARNING, "%s: rtm_msglen is 0 "
211				"(buf=%p lim=%p rtm=%p)", __func__,
212				buf, lim, rtm);
213			break;
214		}
215		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
216			continue;
217		}
218
219		switch (rtm->rtm_type) {
220		case RTM_GET:
221		case RTM_ADD:
222		case RTM_DELETE:
223			/* address related checks */
224			sa = (struct sockaddr *)(rtm + 1);
225			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
226			if ((dst = rti_info[RTAX_DST]) == NULL ||
227			    dst->sa_family != AF_INET6)
228				continue;
229
230			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
231			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
232				continue;
233
234			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
235			    gw->sa_family != AF_LINK)
236				continue;
237			if (ifindex && SDL(gw)->sdl_index != ifindex)
238				continue;
239
240			if (rti_info[RTAX_NETMASK] == NULL)
241				continue;
242
243			/* found */
244			*lenp = rtm->rtm_msglen;
245			return (char *)rtm;
246			/* NOTREACHED */
247		case RTM_NEWADDR:
248		case RTM_DELADDR:
249			ifam = (struct ifa_msghdr *)rtm;
250
251			/* address related checks */
252			sa = (struct sockaddr *)(ifam + 1);
253			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
254			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
255			    (ifa->sa_family != AF_INET &&
256			     ifa->sa_family != AF_INET6))
257				continue;
258
259			if (ifa->sa_family == AF_INET6 &&
260			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
261			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
262				continue;
263
264			if (ifindex && ifam->ifam_index != ifindex)
265				continue;
266
267			/* found */
268			*lenp = ifam->ifam_msglen;
269			return (char *)rtm;
270			/* NOTREACHED */
271#ifdef RTM_IFANNOUNCE
272		case RTM_IFANNOUNCE:
273#endif
274		case RTM_IFINFO:
275			/* found */
276			*lenp = rtm->rtm_msglen;
277			return (char *)rtm;
278			/* NOTREACHED */
279		}
280	}
281
282	return (char *)rtm;
283}
284#undef FILTER_MATCH
285
286const struct in6_addr *
287get_addr(const void *buf)
288{
289	const struct rt_msghdr *rtm = buf;
290	const struct sockaddr *sa, *rti_info[RTAX_MAX];
291
292	sa = (const struct sockaddr *)(rtm + 1);
293	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
294
295	return &SIN6(rti_info[RTAX_DST])->sin6_addr;
296}
297
298unsigned int
299get_rtm_ifindex(const void *buf)
300{
301	const struct rt_msghdr *rtm = buf;
302	const struct sockaddr *sa, *rti_info[RTAX_MAX];
303
304	sa = (const struct sockaddr *)(rtm + 1);
305	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
306
307	return SDL(rti_info[RTAX_GATEWAY])->sdl_index;
308}
309
310unsigned int
311get_ifm_ifindex(const void *buf)
312{
313	const struct if_msghdr *ifm = buf;
314
315	return ifm->ifm_index;
316}
317
318unsigned int
319get_ifam_ifindex(const void *buf)
320{
321	const struct ifa_msghdr *ifam = buf;
322
323	return ifam->ifam_index;
324}
325
326int
327get_ifm_flags(const void *buf)
328{
329	const struct if_msghdr *ifm = buf;
330
331	return ifm->ifm_flags;
332}
333
334#ifdef RTM_IFANNOUNCE
335unsigned int
336get_ifan_ifindex(const void *buf)
337{
338	const struct if_announcemsghdr *ifan = buf;
339
340	return ifan->ifan_index;
341}
342
343int
344get_ifan_what(const void *buf)
345{
346	const struct if_announcemsghdr *ifan = buf;
347
348	return (int)ifan->ifan_what;
349}
350#endif
351
352int
353get_prefixlen(const void *buf)
354{
355	const struct rt_msghdr *rtm = buf;
356	const struct sockaddr *sa, *rti_info[RTAX_MAX];
357	const unsigned char *p, *lim;
358
359	sa = (const struct sockaddr *)(rtm + 1);
360	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
361	sa = rti_info[RTAX_NETMASK];
362
363	p = (const unsigned char *)(&SIN6(sa)->sin6_addr);
364	lim = (const unsigned char *)sa + sa->sa_len;
365	return prefixlen(p, lim);
366}
367
368int
369prefixlen(const unsigned char *p, const unsigned char *lim)
370{
371	int masklen;
372
373	for (masklen = 0; p < lim; p++) {
374		switch (*p) {
375		case 0xff:
376			masklen += 8;
377			break;
378		case 0xfe:
379			masklen += 7;
380			break;
381		case 0xfc:
382			masklen += 6;
383			break;
384		case 0xf8:
385			masklen += 5;
386			break;
387		case 0xf0:
388			masklen += 4;
389			break;
390		case 0xe0:
391			masklen += 3;
392			break;
393		case 0xc0:
394			masklen += 2;
395			break;
396		case 0x80:
397			masklen += 1;
398			break;
399		case 0x00:
400			break;
401		default:
402			return -1;
403		}
404	}
405
406	return masklen;
407}
408
409int
410rtmsg_type(const void *buf)
411{
412	const struct rt_msghdr *rtm = buf;
413
414	return rtm->rtm_type;
415}
416
417const char *
418rtmsg_typestr(const void *buf)
419{
420	const struct rt_msghdr *rtm = buf;
421
422	return rtm->rtm_type < __arraycount(rtm_names)
423	    ? rtm_names[rtm->rtm_type] : "*unknown*";
424}
425
426int
427rtmsg_len(const void *buf)
428{
429	const struct rt_msghdr *rtm = buf;
430
431	return rtm->rtm_msglen;
432}
433