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 *
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#ifdef INET6
61static void in6_fillscopeid(struct sockaddr_in6 *);
62#endif
63
64/*
65 * For all bits set in "mask", compare the corresponding bits in
66 * "dst" and "src", and see if they match. Returns 0 if the addresses
67 * match.
68 */
69static int
70bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
71{
72	int i;
73	u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
74
75	for (i = 0; i < bytelen; i++)
76		if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
77			return (1);
78	return (0);
79}
80
81/*
82 * Similar to code in ifconfig.c. Fill in the scope ID for link-local
83 * addresses returned by getifaddrs().
84 */
85#ifdef INET6
86static void
87in6_fillscopeid(struct sockaddr_in6 *sin6)
88{
89	u_int16_t ifindex;
90
91        if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
92		ifindex = ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
93		if (sin6->sin6_scope_id == 0 && ifindex != 0) {
94			sin6->sin6_scope_id = ifindex;
95			*(u_int16_t *)&sin6->sin6_addr.s6_addr[2] = 0;
96		}
97	}
98}
99#endif
100
101/*
102 * Find a server address that can be used by `caller' to contact
103 * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
104 * non-NULL, it is used instead of `caller' as a hint suggesting
105 * the best address (e.g. the `r_addr' field of an rpc, which
106 * contains the rpcbind server address that the caller used).
107 *
108 * Returns the best server address as a malloc'd "universal address"
109 * string which should be freed by the caller. On error, returns NULL.
110 */
111char *
112addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
113	  char *netid)
114{
115	struct ifaddrs *ifap, *ifp = NULL, *bestif;
116	struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
117	struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
118	struct sockaddr_storage ss;
119	struct netconfig *nconf;
120	char *caller_uaddr = NULL, *hint_uaddr = NULL;
121	char *ret = NULL;
122
123#ifdef ND_DEBUG
124	if (debugging)
125		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
126		    clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
127#endif
128	caller_sa = caller->buf;
129	if ((nconf = rpcbind_get_conf(netid)) == NULL)
130		goto freeit;
131	if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
132		goto freeit;
133
134	/*
135	 * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
136	 * address family is different from that of the caller.
137	 */
138	hint_sa = NULL;
139	if (clnt_uaddr != NULL) {
140		hint_uaddr = clnt_uaddr;
141		if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
142			goto freeit;
143		hint_sa = hint_nbp->buf;
144	}
145	if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
146		hint_uaddr = caller_uaddr;
147		hint_sa = caller->buf;
148	}
149
150#ifdef ND_DEBUG
151	if (debugging)
152		fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
153#endif
154	/* Local caller, just return the server address. */
155	if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
156	    strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
157		ret = strdup(serv_uaddr);
158		goto freeit;
159	}
160
161	if (getifaddrs(&ifp) < 0)
162		goto freeit;
163
164	/*
165	 * Loop through all interfaces. For each interface, see if it
166	 * is either the loopback interface (which we always listen
167	 * on) or is one of the addresses the program bound to (the
168	 * wildcard by default, or a subset if -h is specified) and
169	 * the network portion of its address is equal to that of the
170	 * client.  If so, we have found the interface that we want to
171	 * use.
172	 */
173	bestif = NULL;
174	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
175		ifsa = ifap->ifa_addr;
176		ifmasksa = ifap->ifa_netmask;
177
178		if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
179		    !(ifap->ifa_flags & IFF_UP))
180			continue;
181
182		if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
183			continue;
184
185		switch (hint_sa->sa_family) {
186		case AF_INET:
187			/*
188			 * If the hint address matches this interface
189			 * address/netmask, then we're done.
190			 */
191			if (!bitmaskcmp(&SA2SINADDR(ifsa),
192			    &SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
193			    sizeof(struct in_addr))) {
194				bestif = ifap;
195				goto found;
196			}
197			break;
198#ifdef INET6
199		case AF_INET6:
200			/*
201			 * For v6 link local addresses, if the caller is on
202			 * a link-local address then use the scope id to see
203			 * which one.
204			 */
205			in6_fillscopeid(SA2SIN6(ifsa));
206			if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
207			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
208			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
209				if (SA2SIN6(ifsa)->sin6_scope_id ==
210				    SA2SIN6(caller_sa)->sin6_scope_id) {
211					bestif = ifap;
212					goto found;
213				}
214			} else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
215			    &SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
216			    sizeof(struct in6_addr))) {
217				bestif = ifap;
218				goto found;
219			}
220			break;
221#endif
222		default:
223			continue;
224		}
225
226		/*
227		 * Remember the first possibly useful interface, preferring
228		 * "normal" to point-to-point and loopback ones.
229		 */
230		if (bestif == NULL ||
231		    (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
232		    (bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))))
233			bestif = ifap;
234	}
235	if (bestif == NULL)
236		goto freeit;
237
238found:
239	/*
240	 * Construct the new address using the address from
241	 * `bestif', and the port number from `serv_uaddr'.
242	 */
243	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
244	if (serv_nbp == NULL)
245		goto freeit;
246	serv_sa = serv_nbp->buf;
247
248	memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
249	switch (ss.ss_family) {
250	case AF_INET:
251		SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
252		break;
253#ifdef INET6
254	case AF_INET6:
255		SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
256		break;
257#endif
258	}
259	tbuf.len = ss.ss_len;
260	tbuf.maxlen = sizeof(ss);
261	tbuf.buf = &ss;
262	ret = taddr2uaddr(nconf, &tbuf);
263
264freeit:
265	if (caller_uaddr != NULL)
266		free(caller_uaddr);
267	if (hint_nbp != NULL) {
268		free(hint_nbp->buf);
269		free(hint_nbp);
270	}
271	if (serv_nbp != NULL) {
272		free(serv_nbp->buf);
273		free(serv_nbp);
274	}
275	if (ifp != NULL)
276		freeifaddrs(ifp);
277
278#ifdef ND_DEBUG
279	if (debugging)
280		fprintf(stderr, "addrmerge: returning %s\n", ret);
281#endif
282	return ret;
283}
284
285void
286network_init(void)
287{
288#ifdef INET6
289	struct ifaddrs *ifap, *ifp;
290	struct ipv6_mreq mreq6;
291	unsigned int ifindex;
292	int s;
293#endif
294	int ecode;
295	struct addrinfo hints, *res;
296
297	memset(&hints, 0, sizeof hints);
298	hints.ai_family = AF_INET;
299	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
300		if (debugging)
301			fprintf(stderr, "can't get local ip4 address: %s\n",
302			    gai_strerror(ecode));
303	} else {
304		local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
305		if (local_in4 == NULL) {
306			if (debugging)
307				fprintf(stderr, "can't alloc local ip4 addr\n");
308		}
309		memcpy(local_in4, res->ai_addr, sizeof *local_in4);
310	}
311
312#ifdef INET6
313	hints.ai_family = AF_INET6;
314	if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
315		if (debugging)
316			fprintf(stderr, "can't get local ip6 address: %s\n",
317			    gai_strerror(ecode));
318	} else {
319		local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
320		if (local_in6 == NULL) {
321			if (debugging)
322				fprintf(stderr, "can't alloc local ip6 addr\n");
323		}
324		memcpy(local_in6, res->ai_addr, sizeof *local_in6);
325	}
326
327	/*
328	 * Now join the RPC ipv6 multicast group on all interfaces.
329	 */
330	if (getifaddrs(&ifp) < 0)
331		return;
332
333	mreq6.ipv6mr_interface = 0;
334	inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
335
336	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
337
338	/*
339	 * Loop through all interfaces. For each IPv6 multicast-capable
340	 * interface, join the RPC multicast group on that interface.
341	 */
342	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
343		if (ifap->ifa_addr->sa_family != AF_INET6 ||
344		    !(ifap->ifa_flags & IFF_MULTICAST))
345			continue;
346		ifindex = if_nametoindex(ifap->ifa_name);
347		if (ifindex == mreq6.ipv6mr_interface)
348			/*
349			 * Already did this one.
350			 */
351			continue;
352		mreq6.ipv6mr_interface = ifindex;
353		if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
354		    sizeof mreq6) < 0)
355			if (debugging)
356				perror("setsockopt v6 multicast");
357	}
358#endif
359
360	/* close(s); */
361}
362
363struct sockaddr *
364local_sa(int af)
365{
366	switch (af) {
367	case AF_INET:
368		return (struct sockaddr *)local_in4;
369#ifdef INET6
370	case AF_INET6:
371		return (struct sockaddr *)local_in6;
372#endif
373	default:
374		return NULL;
375	}
376}
377