xref: /netbsd-src/usr.sbin/rpcbind/util.c (revision 5aefcfdc06931dd97e76246d2fe0302f7b3fe094)
1 /*	$NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $	*/
2 
3 /*-
4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Frank van der Linden.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/types.h>
40 #include <sys/socket.h>
41 #include <sys/queue.h>
42 #include <net/if.h>
43 #include <netinet/in.h>
44 #include <ifaddrs.h>
45 #include <sys/poll.h>
46 #include <rpc/rpc.h>
47 #include <errno.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #include <netdb.h>
52 #include <netconfig.h>
53 #include <stdio.h>
54 #include <arpa/inet.h>
55 
56 #include "rpcbind.h"
57 
58 static struct sockaddr_in *local_in4;
59 #ifdef INET6
60 static struct sockaddr_in6 *local_in6;
61 #endif
62 
63 static int bitmaskcmp __P((void *, void *, void *, int));
64 #ifdef INET6
65 static void in6_fillscopeid __P((struct sockaddr_in6 *));
66 #endif
67 
68 /*
69  * For all bits set in "mask", compare the corresponding bits in
70  * "dst" and "src", and see if they match.
71  */
72 static int
73 bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
74 {
75 	int i, j;
76 	u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
77 	u_int8_t bitmask;
78 
79 	for (i = 0; i < bytelen; i++) {
80 		for (j = 0; j < 8; j++) {
81 			bitmask = 1 << j;
82 			if (!(netmask[i] & bitmask))
83 				continue;
84 			if ((p1[i] & bitmask) != (p2[i] & bitmask))
85 				return 1;
86 		}
87 	}
88 
89 	return 0;
90 }
91 
92 /*
93  * Taken from ifconfig.c
94  */
95 #ifdef INET6
96 static void
97 in6_fillscopeid(struct sockaddr_in6 *sin6)
98 {
99         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
100                 sin6->sin6_scope_id =
101                         ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
102                 sin6->sin6_addr.s6_addr[2] = sin6->sin6_addr.s6_addr[3] = 0;
103         }
104 }
105 #endif
106 
107 char *
108 addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
109 	  char *netid)
110 {
111 	struct ifaddrs *ifap, *ifp, *bestif;
112 #ifdef INET6
113 	struct sockaddr_in6 *servsin6, *sin6mask, *clntsin6, *ifsin6, *realsin6;
114 	struct sockaddr_in6 *newsin6;
115 #endif
116 	struct sockaddr_in *servsin, *sinmask, *clntsin, *newsin, *ifsin;
117 	struct netbuf *serv_nbp, *clnt_nbp = NULL, tbuf;
118 	struct sockaddr *serv_sa;
119 	struct sockaddr *clnt_sa;
120 	struct sockaddr_storage ss;
121 	struct netconfig *nconf;
122 	struct sockaddr *clnt = caller->buf;
123 	char *ret = NULL;
124 
125 #ifdef ND_DEBUG
126 	if (debugging)
127 		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
128 		    clnt_uaddr, netid);
129 #endif
130 	nconf = getnetconfigent(netid);
131 	if (nconf == NULL)
132 		return NULL;
133 
134 	/*
135 	 * Local merge, just return a duplicate.
136 	 */
137 	if (clnt_uaddr != NULL && strncmp(clnt_uaddr, "0.0.0.0.", 8) == 0)
138 		return strdup(clnt_uaddr);
139 
140 	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
141 	if (serv_nbp == NULL)
142 		return NULL;
143 
144 	serv_sa = (struct sockaddr *)serv_nbp->buf;
145 	if (clnt_uaddr != NULL) {
146 		clnt_nbp = uaddr2taddr(nconf, clnt_uaddr);
147 		clnt_sa = (struct sockaddr *)clnt_nbp->buf;
148 	} else {
149 		clnt_sa = (struct sockaddr *)
150 		    malloc(sizeof (struct sockaddr_storage));
151 		memcpy(clnt_sa, clnt, clnt->sa_len);
152 	}
153 
154 	if (getifaddrs(&ifp) < 0)
155 		return 0;
156 
157 	/*
158 	 * Loop through all interfaces. For each interface, see if the
159 	 * network portion of its address is equal to that of the client.
160 	 * If so, we have found the interface that we want to use.
161 	 */
162 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
163 		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
164 		    !(ifap->ifa_flags & IFF_UP))
165 			continue;
166 
167 		switch (clnt->sa_family) {
168 		case AF_INET:
169 			/*
170 			 * realsin: address that recvfrom gave us.
171 			 * ifsin: address of interface being examined.
172 			 * clntsin: address that client want us to contact
173 			 *           it on
174 			 * servsin: local address of RPC service.
175 			 * sinmask: netmask of this interface
176 			 * newsin: initially a copy of clntsin, eventually
177 			 *         the merged address
178 			 */
179 			servsin = (struct sockaddr_in *)serv_sa;
180 			clntsin = (struct sockaddr_in *)clnt_sa;
181 			sinmask = (struct sockaddr_in *)ifap->ifa_netmask;
182 			newsin = (struct sockaddr_in *)&ss;
183 			ifsin = (struct sockaddr_in *)ifap->ifa_addr;
184 			if (!bitmaskcmp(&ifsin->sin_addr, &clntsin->sin_addr,
185 			    &sinmask->sin_addr, sizeof (struct in_addr))) {
186 				/*
187 				 * Found it.
188 				 */
189 				memcpy(newsin, ifap->ifa_addr,
190 				    clnt_sa->sa_len);
191 				newsin->sin_port = servsin->sin_port;
192 				tbuf.len = clnt_sa->sa_len;
193 				tbuf.maxlen = sizeof (struct sockaddr_storage);
194 				tbuf.buf = newsin;
195 				goto found;
196 			}
197 			break;
198 #ifdef INET6
199 		case AF_INET6:
200 			/*
201 			 * realsin6: address that recvfrom gave us.
202 			 * ifsin6: address of interface being examined.
203 			 * clntsin6: address that client want us to contact
204 			 *           it on
205 			 * servsin6: local address of RPC service.
206 			 * sin6mask: netmask of this interface
207 			 * newsin6: initially a copy of clntsin, eventually
208 			 *          the merged address
209 			 *
210 			 * For v6 link local addresses, if the client contacted
211 			 * us via a link-local address, and wants us to reply
212 			 * to one, use the scope id to see which one.
213 			 */
214 			realsin6 = (struct sockaddr_in6 *)clnt;
215 			ifsin6 = (struct sockaddr_in6 *)ifap->ifa_addr;
216 			in6_fillscopeid(ifsin6);
217 			clntsin6 = (struct sockaddr_in6 *)clnt_sa;
218 			servsin6 = (struct sockaddr_in6 *)serv_sa;
219 			sin6mask = (struct sockaddr_in6 *)ifap->ifa_netmask;
220 			newsin6 = (struct sockaddr_in6 *)&ss;
221 			if (IN6_IS_ADDR_LINKLOCAL(&ifsin6->sin6_addr) &&
222 			    IN6_IS_ADDR_LINKLOCAL(&realsin6->sin6_addr) &&
223 			    IN6_IS_ADDR_LINKLOCAL(&clntsin6->sin6_addr)) {
224 				if (ifsin6->sin6_scope_id !=
225 				    realsin6->sin6_scope_id)
226 					continue;
227 match:
228 				memcpy(newsin6, ifsin6, clnt_sa->sa_len);
229 				newsin6->sin6_port = servsin6->sin6_port;
230 				tbuf.maxlen = sizeof (struct sockaddr_storage);
231 				tbuf.len = clnt_sa->sa_len;
232 				tbuf.buf = newsin6;
233 				goto found;
234 			}
235 			if (!bitmaskcmp(&ifsin6->sin6_addr,
236 			    &clntsin6->sin6_addr, &sin6mask->sin6_addr,
237 			    sizeof (struct in6_addr)))
238 				goto match;
239 			break;
240 #endif
241 		default:
242 			goto freeit;
243 		}
244 	}
245 	/*
246 	 * Didn't find anything. Get the first possibly useful interface,
247 	 * preferring "normal" interfaces to point-to-point and loopback
248 	 * ones.
249 	 */
250 	bestif = NULL;
251 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
252 		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
253 		    !(ifap->ifa_flags & IFF_UP))
254 			continue;
255 		if (!(ifap->ifa_flags & IFF_LOOPBACK) &&
256 		    !(ifap->ifa_flags & IFF_POINTOPOINT)) {
257 			bestif = ifap;
258 			break;
259 		}
260 		if (bestif == NULL)
261 			bestif = ifap;
262 		else if ((bestif->ifa_flags & IFF_LOOPBACK) &&
263 		    !(ifap->ifa_flags & IFF_LOOPBACK))
264 			bestif = ifap;
265 	}
266 	ifap = bestif;
267 found:
268 	if (ifap != NULL)
269 		ret = taddr2uaddr(nconf, &tbuf);
270 freeit:
271 	freenetconfigent(nconf);
272 	free(serv_sa);
273 	free(serv_nbp);
274 	if (clnt_sa != NULL)
275 		free(clnt_sa);
276 	if (clnt_nbp != NULL)
277 		free(clnt_nbp);
278 	freeifaddrs(ifp);
279 
280 #ifdef ND_DEBUG
281 	if (debugging)
282 		fprintf(stderr, "addrmerge: returning %s\n", ret);
283 #endif
284 	return ret;
285 }
286 
287 void
288 network_init()
289 {
290 #ifdef INET6
291 	struct ifaddrs *ifap, *ifp;
292 	struct ipv6_mreq mreq6;
293 	int ifindex, s;
294 #endif
295 	int ecode;
296 	struct addrinfo hints, *res;
297 
298 	memset(&hints, 0, sizeof hints);
299 	hints.ai_family = AF_INET;
300 	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
301 		if (debugging)
302 			fprintf(stderr, "can't get local ip4 address: %s\n",
303 			    gai_strerror(ecode));
304 	} else {
305 		local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
306 		if (local_in4 == NULL) {
307 			if (debugging)
308 				fprintf(stderr, "can't alloc local ip4 addr\n");
309 		}
310 		memcpy(local_in4, res->ai_addr, sizeof *local_in4);
311 	}
312 
313 #ifdef INET6
314 	hints.ai_family = AF_INET6;
315 	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
316 		if (debugging)
317 			fprintf(stderr, "can't get local ip6 address: %s\n",
318 			    gai_strerror(ecode));
319 	} else {
320 		local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
321 		if (local_in6 == NULL) {
322 			if (debugging)
323 				fprintf(stderr, "can't alloc local ip6 addr\n");
324 		}
325 		memcpy(local_in6, res->ai_addr, sizeof *local_in6);
326 	}
327 
328 	/*
329 	 * Now join the RPC ipv6 multicast group on all interfaces.
330 	 */
331 	if (getifaddrs(&ifp) < 0)
332 		return;
333 
334 	mreq6.ipv6mr_interface = 0;
335 	inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
336 
337 	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
338 
339 	/*
340 	 * Loop through all interfaces. For each interface, see if the
341 	 * network portion of its address is equal to that of the client.
342 	 * If so, we have found the interface that we want to use.
343 	 */
344 	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
345 		if (ifap->ifa_addr->sa_family != AF_INET6 ||
346 		    !(ifap->ifa_flags & IFF_MULTICAST))
347 			continue;
348 		ifindex = if_nametoindex(ifap->ifa_name);
349 		if (ifindex == mreq6.ipv6mr_interface)
350 			/*
351 			 * Already did this one.
352 			 */
353 			continue;
354 		mreq6.ipv6mr_interface = ifindex;
355 		if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
356 		    sizeof mreq6) < 0)
357 			if (debugging)
358 				perror("setsockopt v6 multicast");
359 	}
360 #endif
361 
362 	/* close(s); */
363 }
364 
365 struct sockaddr *
366 local_sa(int af)
367 {
368 	switch (af) {
369 	case AF_INET:
370 		return (struct sockaddr *)local_in4;
371 #ifdef INET6
372 	case AF_INET6:
373 		return (struct sockaddr *)local_in6;
374 #endif
375 	default:
376 		return NULL;
377 	}
378 }
379