xref: /freebsd/usr.sbin/rpcbind/util.c (revision 99e8005137088aafb1350e23b113d69b01b0820f)
1 /*
2  * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
3  * $FreeBSD$
4  */
5 
6 /*-
7  * Copyright (c) 2000 The NetBSD Foundation, Inc.
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to The NetBSD Foundation
11  * by Frank van der Linden.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by the NetBSD
24  *	Foundation, Inc. and its contributors.
25  * 4. Neither the name of The NetBSD Foundation nor the names of its
26  *    contributors may be used to endorse or promote products derived
27  *    from this software without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
30  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
31  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
32  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
33  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39  * POSSIBILITY OF SUCH DAMAGE.
40  */
41 
42 #include <sys/types.h>
43 #include <sys/socket.h>
44 #include <sys/queue.h>
45 #include <net/if.h>
46 #include <netinet/in.h>
47 #include <ifaddrs.h>
48 #include <sys/poll.h>
49 #include <rpc/rpc.h>
50 #include <errno.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <netdb.h>
55 #include <netconfig.h>
56 #include <stdio.h>
57 #include <arpa/inet.h>
58 
59 #include "rpcbind.h"
60 
61 static struct sockaddr_in *local_in4;
62 #ifdef INET6
63 static struct sockaddr_in6 *local_in6;
64 #endif
65 
66 static int bitmaskcmp __P((void *, void *, void *, int));
67 #ifdef INET6
68 static void in6_fillscopeid __P((struct sockaddr_in6 *));
69 #endif
70 
71 /*
72  * For all bits set in "mask", compare the corresponding bits in
73  * "dst" and "src", and see if they match.
74  */
75 static int
76 bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
77 {
78 	int i, j;
79 	u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
80 	u_int8_t bitmask;
81 
82 	for (i = 0; i < bytelen; i++) {
83 		for (j = 0; j < 8; j++) {
84 			bitmask = 1 << j;
85 			if (!(netmask[i] & bitmask))
86 				continue;
87 			if ((p1[i] & bitmask) != (p2[i] & bitmask))
88 				return 1;
89 		}
90 	}
91 
92 	return 0;
93 }
94 
95 /*
96  * Taken from ifconfig.c
97  */
98 #ifdef INET6
99 static void
100 in6_fillscopeid(struct sockaddr_in6 *sin6)
101 {
102         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
103                 sin6->sin6_scope_id =
104                         ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
105                 sin6->sin6_addr.s6_addr[2] = sin6->sin6_addr.s6_addr[3] = 0;
106         }
107 }
108 #endif
109 
110 char *
111 addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
112 	  char *netid)
113 {
114 	struct ifaddrs *ifap, *ifp, *bestif;
115 #ifdef INET6
116 	struct sockaddr_in6 *servsin6, *sin6mask, *clntsin6, *ifsin6, *realsin6;
117 	struct sockaddr_in6 *newsin6;
118 #endif
119 	struct sockaddr_in *servsin, *sinmask, *clntsin, *newsin, *ifsin;
120 	struct netbuf *serv_nbp, *clnt_nbp = NULL, tbuf;
121 	struct sockaddr *serv_sa;
122 	struct sockaddr *clnt_sa;
123 	struct sockaddr_storage ss;
124 	struct netconfig *nconf;
125 	struct sockaddr *clnt = caller->buf;
126 	char *ret = NULL;
127 
128 #ifdef ND_DEBUG
129 	if (debugging)
130 		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
131 		    clnt_uaddr, netid);
132 #endif
133 	nconf = getnetconfigent(netid);
134 	if (nconf == NULL)
135 		return NULL;
136 
137 	/*
138 	 * Local merge, just return a duplicate.
139 	 */
140 	if (clnt_uaddr != NULL && strncmp(clnt_uaddr, "0.0.0.0.", 8) == 0)
141 		return strdup(clnt_uaddr);
142 
143 	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
144 	if (serv_nbp == NULL)
145 		return NULL;
146 
147 	serv_sa = (struct sockaddr *)serv_nbp->buf;
148 	if (clnt_uaddr != NULL) {
149 		clnt_nbp = uaddr2taddr(nconf, clnt_uaddr);
150 		if (clnt_nbp == NULL) {
151 			free(serv_nbp);
152 			return NULL;
153 		}
154 		clnt_sa = (struct sockaddr *)clnt_nbp->buf;
155 		if (clnt_sa->sa_family == AF_LOCAL) {
156 			free(serv_nbp);
157 			free(clnt_nbp);
158 			free(clnt_sa);
159 			return strdup(clnt_uaddr);
160 		}
161 	} else {
162 		clnt_sa = (struct sockaddr *)
163 		    malloc(sizeof (struct sockaddr_storage));
164 		memcpy(clnt_sa, clnt, clnt->sa_len);
165 	}
166 
167 	if (getifaddrs(&ifp) < 0) {
168 		free(serv_nbp);
169 		free(clnt_sa);
170 		if (clnt_nbp != NULL)
171 			free(clnt_nbp);
172 		return 0;
173 	}
174 
175 	/*
176 	 * Loop through all interfaces. For each interface, see if the
177 	 * network portion of its address is equal to that of the client.
178 	 * If so, we have found the interface that we want to use.
179 	 */
180 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
181 		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
182 		    !(ifap->ifa_flags & IFF_UP))
183 			continue;
184 
185 		switch (clnt->sa_family) {
186 		case AF_INET:
187 			/*
188 			 * realsin: address that recvfrom gave us.
189 			 * ifsin: address of interface being examined.
190 			 * clntsin: address that client want us to contact
191 			 *           it on
192 			 * servsin: local address of RPC service.
193 			 * sinmask: netmask of this interface
194 			 * newsin: initially a copy of clntsin, eventually
195 			 *         the merged address
196 			 */
197 			servsin = (struct sockaddr_in *)serv_sa;
198 			clntsin = (struct sockaddr_in *)clnt_sa;
199 			sinmask = (struct sockaddr_in *)ifap->ifa_netmask;
200 			newsin = (struct sockaddr_in *)&ss;
201 			ifsin = (struct sockaddr_in *)ifap->ifa_addr;
202 			if (!bitmaskcmp(&ifsin->sin_addr, &clntsin->sin_addr,
203 			    &sinmask->sin_addr, sizeof (struct in_addr))) {
204 				goto found;
205 			}
206 			break;
207 #ifdef INET6
208 		case AF_INET6:
209 			/*
210 			 * realsin6: address that recvfrom gave us.
211 			 * ifsin6: address of interface being examined.
212 			 * clntsin6: address that client want us to contact
213 			 *           it on
214 			 * servsin6: local address of RPC service.
215 			 * sin6mask: netmask of this interface
216 			 * newsin6: initially a copy of clntsin, eventually
217 			 *          the merged address
218 			 *
219 			 * For v6 link local addresses, if the client contacted
220 			 * us via a link-local address, and wants us to reply
221 			 * to one, use the scope id to see which one.
222 			 */
223 			realsin6 = (struct sockaddr_in6 *)clnt;
224 			ifsin6 = (struct sockaddr_in6 *)ifap->ifa_addr;
225 			in6_fillscopeid(ifsin6);
226 			clntsin6 = (struct sockaddr_in6 *)clnt_sa;
227 			servsin6 = (struct sockaddr_in6 *)serv_sa;
228 			sin6mask = (struct sockaddr_in6 *)ifap->ifa_netmask;
229 			newsin6 = (struct sockaddr_in6 *)&ss;
230 			if (IN6_IS_ADDR_LINKLOCAL(&ifsin6->sin6_addr) &&
231 			    IN6_IS_ADDR_LINKLOCAL(&realsin6->sin6_addr) &&
232 			    IN6_IS_ADDR_LINKLOCAL(&clntsin6->sin6_addr)) {
233 				if (ifsin6->sin6_scope_id !=
234 				    realsin6->sin6_scope_id)
235 					continue;
236 				goto found;
237 			}
238 			if (!bitmaskcmp(&ifsin6->sin6_addr,
239 			    &clntsin6->sin6_addr, &sin6mask->sin6_addr,
240 			    sizeof (struct in6_addr)))
241 				goto found;
242 			break;
243 #endif
244 		default:
245 			goto freeit;
246 		}
247 	}
248 	/*
249 	 * Didn't find anything. Get the first possibly useful interface,
250 	 * preferring "normal" interfaces to point-to-point and loopback
251 	 * ones.
252 	 */
253 	bestif = NULL;
254 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
255 		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
256 		    !(ifap->ifa_flags & IFF_UP))
257 			continue;
258 		if (!(ifap->ifa_flags & IFF_LOOPBACK) &&
259 		    !(ifap->ifa_flags & IFF_POINTOPOINT)) {
260 			bestif = ifap;
261 			break;
262 		}
263 		if (bestif == NULL)
264 			bestif = ifap;
265 		else if ((bestif->ifa_flags & IFF_LOOPBACK) &&
266 		    !(ifap->ifa_flags & IFF_LOOPBACK))
267 			bestif = ifap;
268 	}
269 	ifap = bestif;
270 found:
271 	switch (clnt->sa_family) {
272 	case AF_INET:
273 		memcpy(newsin, ifap->ifa_addr, clnt_sa->sa_len);
274 		newsin->sin_port = servsin->sin_port;
275 		tbuf.len = clnt_sa->sa_len;
276 		tbuf.maxlen = sizeof (struct sockaddr_storage);
277 		tbuf.buf = newsin;
278 		break;
279 #ifdef INET6
280 	case AF_INET6:
281 		memcpy(newsin6, ifsin6, clnt_sa->sa_len);
282 		newsin6->sin6_port = servsin6->sin6_port;
283 		tbuf.maxlen = sizeof (struct sockaddr_storage);
284 		tbuf.len = clnt_sa->sa_len;
285 		tbuf.buf = newsin6;
286 		break;
287 #endif
288 	default:
289 		goto freeit;
290 	}
291 	if (ifap != NULL)
292 		ret = taddr2uaddr(nconf, &tbuf);
293 freeit:
294 	freenetconfigent(nconf);
295 	free(serv_sa);
296 	free(serv_nbp);
297 	if (clnt_sa != NULL)
298 		free(clnt_sa);
299 	if (clnt_nbp != NULL)
300 		free(clnt_nbp);
301 	freeifaddrs(ifp);
302 
303 #ifdef ND_DEBUG
304 	if (debugging)
305 		fprintf(stderr, "addrmerge: returning %s\n", ret);
306 #endif
307 	return ret;
308 }
309 
310 void
311 network_init()
312 {
313 #ifdef INET6
314 	struct ifaddrs *ifap, *ifp;
315 	struct ipv6_mreq mreq6;
316 	int ifindex, s;
317 #endif
318 	int ecode;
319 	struct addrinfo hints, *res;
320 
321 	memset(&hints, 0, sizeof hints);
322 	hints.ai_family = AF_INET;
323 	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
324 		if (debugging)
325 			fprintf(stderr, "can't get local ip4 address: %s\n",
326 			    gai_strerror(ecode));
327 	} else {
328 		local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
329 		if (local_in4 == NULL) {
330 			if (debugging)
331 				fprintf(stderr, "can't alloc local ip4 addr\n");
332 		}
333 		memcpy(local_in4, res->ai_addr, sizeof *local_in4);
334 	}
335 
336 #ifdef INET6
337 	hints.ai_family = AF_INET6;
338 	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
339 		if (debugging)
340 			fprintf(stderr, "can't get local ip6 address: %s\n",
341 			    gai_strerror(ecode));
342 	} else {
343 		local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
344 		if (local_in6 == NULL) {
345 			if (debugging)
346 				fprintf(stderr, "can't alloc local ip6 addr\n");
347 		}
348 		memcpy(local_in6, res->ai_addr, sizeof *local_in6);
349 	}
350 
351 	/*
352 	 * Now join the RPC ipv6 multicast group on all interfaces.
353 	 */
354 	if (getifaddrs(&ifp) < 0)
355 		return;
356 
357 	mreq6.ipv6mr_interface = 0;
358 	inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
359 
360 	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
361 
362 	/*
363 	 * Loop through all interfaces. For each interface, see if the
364 	 * network portion of its address is equal to that of the client.
365 	 * If so, we have found the interface that we want to use.
366 	 */
367 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
368 		if (ifap->ifa_addr->sa_family != AF_INET6 ||
369 		    !(ifap->ifa_flags & IFF_MULTICAST))
370 			continue;
371 		ifindex = if_nametoindex(ifap->ifa_name);
372 		if (ifindex == mreq6.ipv6mr_interface)
373 			/*
374 			 * Already did this one.
375 			 */
376 			continue;
377 		mreq6.ipv6mr_interface = ifindex;
378 		if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
379 		    sizeof mreq6) < 0)
380 			if (debugging)
381 				perror("setsockopt v6 multicast");
382 	}
383 #endif
384 
385 	/* close(s); */
386 }
387 
388 struct sockaddr *
389 local_sa(int af)
390 {
391 	switch (af) {
392 	case AF_INET:
393 		return (struct sockaddr *)local_in4;
394 #ifdef INET6
395 	case AF_INET6:
396 		return (struct sockaddr *)local_in6;
397 #endif
398 	default:
399 		return NULL;
400 	}
401 }
402