util.c revision 293229 
1/*
2 * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
3 * $FreeBSD: head/usr.sbin/rpcbind/util.c 293229 2016-01-06 00:00:11Z asomers $
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 *
22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
25 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include <sys/types.h>
36#include <sys/socket.h>
37#include <sys/queue.h>
38#include <net/if.h>
39#include <netinet/in.h>
40#include <ifaddrs.h>
41#include <sys/poll.h>
42#include <rpc/rpc.h>
43#include <errno.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47#include <netdb.h>
48#include <netconfig.h>
49#include <stdio.h>
50#include <arpa/inet.h>
51
52#include "rpcbind.h"
53
54static struct sockaddr_in *local_in4;
55#ifdef INET6
56static struct sockaddr_in6 *local_in6;
57#endif
58
59static int bitmaskcmp(struct sockaddr *, struct sockaddr *, struct sockaddr *);
60
61/*
62 * For all bits set in "mask", compare the corresponding bits in
63 * "dst" and "src", and see if they match. Returns 0 if the addresses
64 * match.
65 */
66static int
67bitmaskcmp(struct sockaddr *dst, struct sockaddr *src, struct sockaddr *mask)
68{
69	int i;
70	u_int8_t *p1, *p2, *netmask;
71	int bytelen;
72
73	if (dst->sa_family != src->sa_family ||
74	    dst->sa_family != mask->sa_family)
75		return (1);
76
77	switch (dst->sa_family) {
78	case AF_INET:
79		p1 = (uint8_t*) &SA2SINADDR(dst);
80		p2 = (uint8_t*) &SA2SINADDR(src);
81		netmask = (uint8_t*) &SA2SINADDR(mask);
82		bytelen = sizeof(struct in_addr);
83		break;
84#ifdef INET6
85	case AF_INET6:
86		p1 = (uint8_t*) &SA2SIN6ADDR(dst);
87		p2 = (uint8_t*) &SA2SIN6ADDR(src);
88		netmask = (uint8_t*) &SA2SIN6ADDR(mask);
89		bytelen = sizeof(struct in6_addr);
90		break;
91#endif
92	default:
93		return (1);
94	}
95
96	for (i = 0; i < bytelen; i++)
97		if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
98			return (1);
99	return (0);
100}
101
102/*
103 * Find a server address that can be used by `caller' to contact
104 * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
105 * non-NULL, it is used instead of `caller' as a hint suggesting
106 * the best address (e.g. the `r_addr' field of an rpc, which
107 * contains the rpcbind server address that the caller used).
108 *
109 * Returns the best server address as a malloc'd "universal address"
110 * string which should be freed by the caller. On error, returns NULL.
111 */
112char *
113addrmerge(struct netbuf *caller, const char *serv_uaddr, const char *clnt_uaddr,
114	  const char *netid)
115{
116	struct ifaddrs *ifap, *ifp = NULL, *bestif;
117	struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
118	struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
119	struct sockaddr_storage ss;
120	struct netconfig *nconf;
121	char *caller_uaddr = NULL;
122	const char *hint_uaddr = NULL;
123	char *ret = NULL;
124	int bestif_goodness;
125
126#ifdef ND_DEBUG
127	if (debugging)
128		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
129		    clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
130#endif
131	caller_sa = caller->buf;
132	if ((nconf = rpcbind_get_conf(netid)) == NULL)
133		goto freeit;
134	if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
135		goto freeit;
136
137	/*
138	 * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
139	 * address family is different from that of the caller.
140	 */
141	hint_sa = NULL;
142	if (clnt_uaddr != NULL) {
143		hint_uaddr = clnt_uaddr;
144		if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
145			goto freeit;
146		hint_sa = hint_nbp->buf;
147	}
148	if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
149		hint_uaddr = caller_uaddr;
150		hint_sa = caller->buf;
151	}
152
153#ifdef ND_DEBUG
154	if (debugging)
155		fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
156#endif
157	/* Local caller, just return the server address. */
158	if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
159	    strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
160		ret = strdup(serv_uaddr);
161		goto freeit;
162	}
163
164	if (getifaddrs(&ifp) < 0)
165		goto freeit;
166
167	/*
168	 * Loop through all interface addresses.  We are listening to an address
169	 * if any of the following are true:
170	 * a) It's a loopback address
171	 * b) It was specified with the -h command line option
172	 * c) There were no -h command line options.
173	 *
174	 * Among addresses on which we are listening, choose in order of
175	 * preference an address that is:
176	 *
177	 * a) Equal to the hint
178	 * b) A link local address with the same scope ID as the client's
179	 *    address, if the client's address is also link local
180	 * c) An address on the same subnet as the client's address
181	 * d) A non-localhost, non-p2p address
182	 * e) Any usable address
183	 */
184	bestif = NULL;
185	bestif_goodness = 0;
186	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
187		ifsa = ifap->ifa_addr;
188		ifmasksa = ifap->ifa_netmask;
189
190		/* Skip addresses where we don't listen */
191		if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
192		    !(ifap->ifa_flags & IFF_UP))
193			continue;
194
195		if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
196			continue;
197
198		if ((hint_sa->sa_family == AF_INET) &&
199		    ((((struct sockaddr_in*)hint_sa)->sin_addr.s_addr ==
200		      ((struct sockaddr_in*)ifsa)->sin_addr.s_addr))) {
201			const int goodness = 4;
202
203			bestif_goodness = goodness;
204			bestif = ifap;
205			goto found;
206		}
207#ifdef INET6
208		if ((hint_sa->sa_family == AF_INET6) &&
209		    (0 == memcmp(&((struct sockaddr_in6*)hint_sa)->sin6_addr,
210				 &((struct sockaddr_in6*)ifsa)->sin6_addr,
211				 sizeof(struct in6_addr))) &&
212		    (((struct sockaddr_in6*)hint_sa)->sin6_scope_id ==
213		    (((struct sockaddr_in6*)ifsa)->sin6_scope_id))) {
214			const int goodness = 4;
215
216			bestif_goodness = goodness;
217			bestif = ifap;
218			goto found;
219		}
220		if (hint_sa->sa_family == AF_INET6) {
221			/*
222			 * For v6 link local addresses, if the caller is on
223			 * a link-local address then use the scope id to see
224			 * which one.
225			 */
226			if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
227			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
228			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
229				if (SA2SIN6(ifsa)->sin6_scope_id ==
230				    SA2SIN6(caller_sa)->sin6_scope_id) {
231					const int goodness = 3;
232
233					if (bestif_goodness < goodness) {
234						bestif = ifap;
235						bestif_goodness = goodness;
236					}
237				}
238			}
239		}
240#endif /* INET6 */
241		if (0 == bitmaskcmp(hint_sa, ifsa, ifmasksa)) {
242			const int goodness = 2;
243
244			if (bestif_goodness < goodness) {
245				bestif = ifap;
246				bestif_goodness = goodness;
247			}
248		}
249		if (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
250			const int goodness = 1;
251
252			if (bestif_goodness < goodness) {
253				bestif = ifap;
254				bestif_goodness = goodness;
255			}
256		}
257		if (bestif == NULL)
258			bestif = ifap;
259	}
260	if (bestif == NULL)
261		goto freeit;
262
263found:
264	/*
265	 * Construct the new address using the address from
266	 * `bestif', and the port number from `serv_uaddr'.
267	 */
268	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
269	if (serv_nbp == NULL)
270		goto freeit;
271	serv_sa = serv_nbp->buf;
272
273	memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
274	switch (ss.ss_family) {
275	case AF_INET:
276		SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
277		break;
278#ifdef INET6
279	case AF_INET6:
280		SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
281		break;
282#endif
283	}
284	tbuf.len = ss.ss_len;
285	tbuf.maxlen = sizeof(ss);
286	tbuf.buf = &ss;
287	ret = taddr2uaddr(nconf, &tbuf);
288
289freeit:
290	if (caller_uaddr != NULL)
291		free(caller_uaddr);
292	if (hint_nbp != NULL) {
293		free(hint_nbp->buf);
294		free(hint_nbp);
295	}
296	if (serv_nbp != NULL) {
297		free(serv_nbp->buf);
298		free(serv_nbp);
299	}
300	if (ifp != NULL)
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
310void
311network_init(void)
312{
313#ifdef INET6
314	struct ifaddrs *ifap, *ifp;
315	struct ipv6_mreq mreq6;
316	unsigned int ifindex;
317	int s;
318#endif
319	int ecode;
320	struct addrinfo hints, *res;
321
322	memset(&hints, 0, sizeof hints);
323	hints.ai_family = AF_INET;
324	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
325		if (debugging)
326			fprintf(stderr, "can't get local ip4 address: %s\n",
327			    gai_strerror(ecode));
328	} else {
329		local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
330		if (local_in4 == NULL) {
331			if (debugging)
332				fprintf(stderr, "can't alloc local ip4 addr\n");
333		}
334		memcpy(local_in4, res->ai_addr, sizeof *local_in4);
335	}
336
337#ifdef INET6
338	hints.ai_family = AF_INET6;
339	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
340		if (debugging)
341			fprintf(stderr, "can't get local ip6 address: %s\n",
342			    gai_strerror(ecode));
343	} else {
344		local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
345		if (local_in6 == NULL) {
346			if (debugging)
347				fprintf(stderr, "can't alloc local ip6 addr\n");
348		}
349		memcpy(local_in6, res->ai_addr, sizeof *local_in6);
350	}
351
352	/*
353	 * Now join the RPC ipv6 multicast group on all interfaces.
354	 */
355	if (getifaddrs(&ifp) < 0)
356		return;
357
358	mreq6.ipv6mr_interface = 0;
359	inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
360
361	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
362
363	/*
364	 * Loop through all interfaces. For each IPv6 multicast-capable
365	 * interface, join the RPC multicast group on that interface.
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
388struct sockaddr *
389local_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