1/*
2 * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
3 * $FreeBSD: releng/10.3/usr.sbin/rpcbind/util.c 243187 2012-11-17 20:19:00Z hrs $
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(void *, void *, void *, int);
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(void *dst, void *src, void *mask, int bytelen)
68{
69	int i;
70	u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
71
72	for (i = 0; i < bytelen; i++)
73		if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
74			return (1);
75	return (0);
76}
77
78/*
79 * Find a server address that can be used by `caller' to contact
80 * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
81 * non-NULL, it is used instead of `caller' as a hint suggesting
82 * the best address (e.g. the `r_addr' field of an rpc, which
83 * contains the rpcbind server address that the caller used).
84 *
85 * Returns the best server address as a malloc'd "universal address"
86 * string which should be freed by the caller. On error, returns NULL.
87 */
88char *
89addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
90	  char *netid)
91{
92	struct ifaddrs *ifap, *ifp = NULL, *bestif;
93	struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
94	struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
95	struct sockaddr_storage ss;
96	struct netconfig *nconf;
97	char *caller_uaddr = NULL, *hint_uaddr = NULL;
98	char *ret = NULL;
99
100#ifdef ND_DEBUG
101	if (debugging)
102		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
103		    clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
104#endif
105	caller_sa = caller->buf;
106	if ((nconf = rpcbind_get_conf(netid)) == NULL)
107		goto freeit;
108	if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
109		goto freeit;
110
111	/*
112	 * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
113	 * address family is different from that of the caller.
114	 */
115	hint_sa = NULL;
116	if (clnt_uaddr != NULL) {
117		hint_uaddr = clnt_uaddr;
118		if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
119			goto freeit;
120		hint_sa = hint_nbp->buf;
121	}
122	if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
123		hint_uaddr = caller_uaddr;
124		hint_sa = caller->buf;
125	}
126
127#ifdef ND_DEBUG
128	if (debugging)
129		fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
130#endif
131	/* Local caller, just return the server address. */
132	if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
133	    strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
134		ret = strdup(serv_uaddr);
135		goto freeit;
136	}
137
138	if (getifaddrs(&ifp) < 0)
139		goto freeit;
140
141	/*
142	 * Loop through all interfaces. For each interface, see if it
143	 * is either the loopback interface (which we always listen
144	 * on) or is one of the addresses the program bound to (the
145	 * wildcard by default, or a subset if -h is specified) and
146	 * the network portion of its address is equal to that of the
147	 * client.  If so, we have found the interface that we want to
148	 * use.
149	 */
150	bestif = NULL;
151	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
152		ifsa = ifap->ifa_addr;
153		ifmasksa = ifap->ifa_netmask;
154
155		if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
156		    !(ifap->ifa_flags & IFF_UP))
157			continue;
158
159		if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
160			continue;
161
162		switch (hint_sa->sa_family) {
163		case AF_INET:
164			/*
165			 * If the hint address matches this interface
166			 * address/netmask, then we're done.
167			 */
168			if (!bitmaskcmp(&SA2SINADDR(ifsa),
169			    &SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
170			    sizeof(struct in_addr))) {
171				bestif = ifap;
172				goto found;
173			}
174			break;
175#ifdef INET6
176		case AF_INET6:
177			/*
178			 * For v6 link local addresses, if the caller is on
179			 * a link-local address then use the scope id to see
180			 * which one.
181			 */
182			if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
183			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
184			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
185				if (SA2SIN6(ifsa)->sin6_scope_id ==
186				    SA2SIN6(caller_sa)->sin6_scope_id) {
187					bestif = ifap;
188					goto found;
189				}
190			} else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
191			    &SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
192			    sizeof(struct in6_addr))) {
193				bestif = ifap;
194				goto found;
195			}
196			break;
197#endif
198		default:
199			continue;
200		}
201
202		/*
203		 * Remember the first possibly useful interface, preferring
204		 * "normal" to point-to-point and loopback ones.
205		 */
206		if (bestif == NULL ||
207		    (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
208		    (bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))))
209			bestif = ifap;
210	}
211	if (bestif == NULL)
212		goto freeit;
213
214found:
215	/*
216	 * Construct the new address using the address from
217	 * `bestif', and the port number from `serv_uaddr'.
218	 */
219	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
220	if (serv_nbp == NULL)
221		goto freeit;
222	serv_sa = serv_nbp->buf;
223
224	memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
225	switch (ss.ss_family) {
226	case AF_INET:
227		SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
228		break;
229#ifdef INET6
230	case AF_INET6:
231		SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
232		break;
233#endif
234	}
235	tbuf.len = ss.ss_len;
236	tbuf.maxlen = sizeof(ss);
237	tbuf.buf = &ss;
238	ret = taddr2uaddr(nconf, &tbuf);
239
240freeit:
241	if (caller_uaddr != NULL)
242		free(caller_uaddr);
243	if (hint_nbp != NULL) {
244		free(hint_nbp->buf);
245		free(hint_nbp);
246	}
247	if (serv_nbp != NULL) {
248		free(serv_nbp->buf);
249		free(serv_nbp);
250	}
251	if (ifp != NULL)
252		freeifaddrs(ifp);
253
254#ifdef ND_DEBUG
255	if (debugging)
256		fprintf(stderr, "addrmerge: returning %s\n", ret);
257#endif
258	return ret;
259}
260
261void
262network_init(void)
263{
264#ifdef INET6
265	struct ifaddrs *ifap, *ifp;
266	struct ipv6_mreq mreq6;
267	unsigned int ifindex;
268	int s;
269#endif
270	int ecode;
271	struct addrinfo hints, *res;
272
273	memset(&hints, 0, sizeof hints);
274	hints.ai_family = AF_INET;
275	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
276		if (debugging)
277			fprintf(stderr, "can't get local ip4 address: %s\n",
278			    gai_strerror(ecode));
279	} else {
280		local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
281		if (local_in4 == NULL) {
282			if (debugging)
283				fprintf(stderr, "can't alloc local ip4 addr\n");
284		}
285		memcpy(local_in4, res->ai_addr, sizeof *local_in4);
286	}
287
288#ifdef INET6
289	hints.ai_family = AF_INET6;
290	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
291		if (debugging)
292			fprintf(stderr, "can't get local ip6 address: %s\n",
293			    gai_strerror(ecode));
294	} else {
295		local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
296		if (local_in6 == NULL) {
297			if (debugging)
298				fprintf(stderr, "can't alloc local ip6 addr\n");
299		}
300		memcpy(local_in6, res->ai_addr, sizeof *local_in6);
301	}
302
303	/*
304	 * Now join the RPC ipv6 multicast group on all interfaces.
305	 */
306	if (getifaddrs(&ifp) < 0)
307		return;
308
309	mreq6.ipv6mr_interface = 0;
310	inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
311
312	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
313
314	/*
315	 * Loop through all interfaces. For each IPv6 multicast-capable
316	 * interface, join the RPC multicast group on that interface.
317	 */
318	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
319		if (ifap->ifa_addr->sa_family != AF_INET6 ||
320		    !(ifap->ifa_flags & IFF_MULTICAST))
321			continue;
322		ifindex = if_nametoindex(ifap->ifa_name);
323		if (ifindex == mreq6.ipv6mr_interface)
324			/*
325			 * Already did this one.
326			 */
327			continue;
328		mreq6.ipv6mr_interface = ifindex;
329		if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
330		    sizeof mreq6) < 0)
331			if (debugging)
332				perror("setsockopt v6 multicast");
333	}
334#endif
335
336	/* close(s); */
337}
338
339struct sockaddr *
340local_sa(int af)
341{
342	switch (af) {
343	case AF_INET:
344		return (struct sockaddr *)local_in4;
345#ifdef INET6
346	case AF_INET6:
347		return (struct sockaddr *)local_in6;
348#endif
349	default:
350		return NULL;
351	}
352}
353