1/*	$NetBSD$	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/types.h>
33#include <sys/param.h>
34#include <sys/socket.h>
35#include <netinet/in.h>
36#include <arpa/inet.h>
37#include <arpa/nameser.h>
38#include <netdb.h>
39#include <resolv.h>
40#include <string.h>
41#include <stdlib.h>
42#include <stddef.h>
43#include <ctype.h>
44#include <unistd.h>
45
46#include "addrinfo.h"
47
48#define SUCCESS 0
49#define ANY 0
50#define YES 1
51#define NO  0
52
53static const char in_addrany[] = { 0, 0, 0, 0 };
54static const char in6_addrany[] = {
55	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
56};
57static const char in_loopback[] = { 127, 0, 0, 1 };
58static const char in6_loopback[] = {
59	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
60};
61
62struct sockinet {
63	u_char	si_len;
64	u_char	si_family;
65	u_short	si_port;
66};
67
68static struct afd {
69	int a_af;
70	int a_addrlen;
71	int a_socklen;
72	int a_off;
73	const char *a_addrany;
74	const char *a_loopback;
75} afdl [] = {
76#ifdef INET6
77#define N_INET6 0
78	{PF_INET6, sizeof(struct in6_addr),
79	 sizeof(struct sockaddr_in6),
80	 offsetof(struct sockaddr_in6, sin6_addr),
81	 in6_addrany, in6_loopback},
82#define N_INET  1
83#else
84#define N_INET  0
85#endif
86	{PF_INET, sizeof(struct in_addr),
87	 sizeof(struct sockaddr_in),
88	 offsetof(struct sockaddr_in, sin_addr),
89	 in_addrany, in_loopback},
90	{0, 0, 0, 0, NULL, NULL},
91};
92
93#ifdef INET6
94#define PTON_MAX	16
95#else
96#define PTON_MAX	4
97#endif
98
99
100static int get_name(const char *, struct afd *,
101		    struct addrinfo **, char *, struct addrinfo *,
102		    int);
103static int get_addr(const char *, int, struct addrinfo **,
104		    struct addrinfo *, int);
105static int get_addr0(const char *, int, struct addrinfo **,
106		     struct addrinfo *, int);
107static int str_isnumber(const char *);
108
109static char *ai_errlist[] = {
110	"Success",
111	"Address family for hostname not supported",	/* EAI_ADDRFAMILY */
112	"Temporary failure in name resolution",		/* EAI_AGAIN      */
113	"Invalid value for ai_flags",		       	/* EAI_BADFLAGS   */
114	"Non-recoverable failure in name resolution", 	/* EAI_FAIL       */
115	"ai_family not supported",			/* EAI_FAMILY     */
116	"Memory allocation failure", 			/* EAI_MEMORY     */
117	"No address associated with hostname", 		/* EAI_NODATA     */
118	"hostname nor servname provided, or not known",/* EAI_NONAME     */
119	"servname not supported for ai_socktype",	/* EAI_SERVICE    */
120	"ai_socktype not supported", 			/* EAI_SOCKTYPE   */
121	"System error returned in errno", 		/* EAI_SYSTEM     */
122	"Invalid value for hints",			/* EAI_BADHINTS	  */
123	"Resolved protocol is unknown",			/* EAI_PROTOCOL   */
124	"Unknown error", 				/* EAI_MAX        */
125};
126
127#define GET_CANONNAME(ai, str) \
128if (pai->ai_flags & AI_CANONNAME) {\
129	if (((ai)->ai_canonname = (char *)malloc(strlen(str) + 1)) != NULL) {\
130		strcpy((ai)->ai_canonname, (str));\
131	} else {\
132		error = EAI_MEMORY;\
133		goto free;\
134	}\
135}
136
137#ifdef HAVE_SA_LEN
138#define	SET_AILEN(ai,l) (ai)->ai_addr->sa_len = (ai)->ai_addrlen = (l)
139#else
140#define	SET_AILEN(ai,l) (ai)->ai_addrlen = (l)
141#endif
142
143#define GET_AI(ai, afd, addr, port) {\
144	char *p;\
145	if (((ai) = (struct addrinfo *)malloc(sizeof(struct addrinfo) +\
146					      ((afd)->a_socklen)))\
147	    == NULL) {\
148		error = EAI_MEMORY;\
149		goto free;\
150	}\
151	memcpy(ai, pai, sizeof(struct addrinfo));\
152	(ai)->ai_addr = (struct sockaddr *)((ai) + 1);\
153	memset((ai)->ai_addr, 0, (afd)->a_socklen);\
154	SET_AILEN((ai), (afd)->a_socklen);\
155	(ai)->ai_addr->sa_family = (ai)->ai_family = (afd)->a_af;\
156	((struct sockinet *)(ai)->ai_addr)->si_port = port;\
157	p = (char *)((ai)->ai_addr);\
158	memcpy(p + (afd)->a_off, (addr), (afd)->a_addrlen);\
159}
160
161#define ERR(err) { error = (err); goto bad; }
162
163char *
164gai_strerror(ecode)
165	int ecode;
166{
167	if (ecode < 0 || ecode > EAI_MAX)
168		ecode = EAI_MAX;
169	return ai_errlist[ecode];
170}
171
172void
173freeaddrinfo(ai)
174	struct addrinfo *ai;
175{
176	struct addrinfo *next;
177
178	do {
179		next = ai->ai_next;
180		if (ai->ai_canonname)
181			free(ai->ai_canonname);
182		/* no need to free(ai->ai_addr) */
183		free(ai);
184	} while ((ai = next) != NULL);
185}
186
187static int
188str_isnumber(p)
189	const char *p;
190{
191	char *q = (char *)p;
192	while (*q) {
193		if (! isdigit(*q))
194			return NO;
195		q++;
196	}
197	return YES;
198}
199
200int
201getaddrinfo(hostname, servname, hints, res)
202	const char *hostname, *servname;
203	const struct addrinfo *hints;
204	struct addrinfo **res;
205{
206	struct addrinfo sentinel;
207	struct addrinfo *top = NULL;
208	struct addrinfo *cur;
209	int i, error = 0;
210	char pton[PTON_MAX];
211	struct addrinfo ai;
212	struct addrinfo *pai;
213	u_short port;
214
215	/* initialize file static vars */
216	sentinel.ai_next = NULL;
217	cur = &sentinel;
218	pai = &ai;
219	pai->ai_flags = 0;
220	pai->ai_family = PF_UNSPEC;
221	pai->ai_socktype = ANY;
222	pai->ai_protocol = ANY;
223	pai->ai_addrlen = 0;
224	pai->ai_canonname = NULL;
225	pai->ai_addr = NULL;
226	pai->ai_next = NULL;
227	port = ANY;
228
229	if (hostname == NULL && servname == NULL)
230		return EAI_NONAME;
231	if (hints) {
232		/* error check for hints */
233		if (hints->ai_addrlen || hints->ai_canonname ||
234		    hints->ai_addr || hints->ai_next)
235			ERR(EAI_BADHINTS); /* xxx */
236		if (hints->ai_flags & ~AI_MASK)
237			ERR(EAI_BADFLAGS);
238		switch (hints->ai_family) {
239		case PF_UNSPEC:
240		case PF_INET:
241#ifdef INET6
242		case PF_INET6:
243#endif
244			break;
245		default:
246			ERR(EAI_FAMILY);
247		}
248		memcpy(pai, hints, sizeof(*pai));
249		switch (pai->ai_socktype) {
250		case ANY:
251			switch (pai->ai_protocol) {
252			case ANY:
253				break;
254			case IPPROTO_UDP:
255				pai->ai_socktype = SOCK_DGRAM;
256				break;
257			case IPPROTO_TCP:
258				pai->ai_socktype = SOCK_STREAM;
259				break;
260			default:
261				pai->ai_socktype = SOCK_RAW;
262				break;
263			}
264			break;
265		case SOCK_RAW:
266			break;
267		case SOCK_DGRAM:
268			if (pai->ai_protocol != IPPROTO_UDP &&
269			    pai->ai_protocol != ANY)
270				ERR(EAI_BADHINTS);	/*xxx*/
271			pai->ai_protocol = IPPROTO_UDP;
272			break;
273		case SOCK_STREAM:
274			if (pai->ai_protocol != IPPROTO_TCP &&
275			    pai->ai_protocol != ANY)
276				ERR(EAI_BADHINTS);	/*xxx*/
277			pai->ai_protocol = IPPROTO_TCP;
278			break;
279		default:
280			ERR(EAI_SOCKTYPE);
281			break;
282		}
283	}
284
285	/*
286	 * service port
287	 */
288	if (servname) {
289		if (str_isnumber(servname)) {
290			if (pai->ai_socktype == ANY) {
291				/* caller accept *ANY* socktype */
292				pai->ai_socktype = SOCK_DGRAM;
293				pai->ai_protocol = IPPROTO_UDP;
294			}
295			port = htons(atoi(servname));
296		} else {
297			struct servent *sp;
298			char *proto;
299
300			proto = NULL;
301			switch (pai->ai_socktype) {
302			case ANY:
303				proto = NULL;
304				break;
305			case SOCK_DGRAM:
306				proto = "udp";
307				break;
308			case SOCK_STREAM:
309				proto = "tcp";
310				break;
311			default:
312				fprintf(stderr, "panic!\n");
313				break;
314			}
315			if ((sp = getservbyname(servname, proto)) == NULL)
316				ERR(EAI_SERVICE);
317			port = sp->s_port;
318			if (pai->ai_socktype == ANY) {
319				if (strcmp(sp->s_proto, "udp") == 0) {
320					pai->ai_socktype = SOCK_DGRAM;
321					pai->ai_protocol = IPPROTO_UDP;
322				} else if (strcmp(sp->s_proto, "tcp") == 0) {
323					pai->ai_socktype = SOCK_STREAM;
324					pai->ai_protocol = IPPROTO_TCP;
325				} else
326					ERR(EAI_PROTOCOL);	/*xxx*/
327			}
328		}
329	}
330
331	/*
332	 * hostname == NULL.
333	 * passive socket -> anyaddr (0.0.0.0 or ::)
334	 * non-passive socket -> localhost (127.0.0.1 or ::1)
335	 */
336	if (hostname == NULL) {
337		struct afd *afd;
338		int s;
339
340		for (afd = &afdl[0]; afd->a_af; afd++) {
341			if (!(pai->ai_family == PF_UNSPEC
342			   || pai->ai_family == afd->a_af)) {
343				continue;
344			}
345
346			/*
347			 * filter out AFs that are not supported by the kernel
348			 * XXX errno?
349			 */
350			s = socket(afd->a_af, SOCK_DGRAM, 0);
351			if (s < 0)
352				continue;
353			close(s);
354
355			if (pai->ai_flags & AI_PASSIVE) {
356				GET_AI(cur->ai_next, afd, afd->a_addrany, port);
357				/* xxx meaningless?
358				 * GET_CANONNAME(cur->ai_next, "anyaddr");
359				 */
360			} else {
361				GET_AI(cur->ai_next, afd, afd->a_loopback,
362					port);
363				/* xxx meaningless?
364				 * GET_CANONNAME(cur->ai_next, "localhost");
365				 */
366			}
367			cur = cur->ai_next;
368		}
369		top = sentinel.ai_next;
370		if (top)
371			goto good;
372		else
373			ERR(EAI_FAMILY);
374	}
375
376	/* hostname as numeric name */
377	for (i = 0; afdl[i].a_af; i++) {
378		if (inet_pton(afdl[i].a_af, hostname, pton) == 1) {
379			u_long v4a;
380			u_char pfx;
381
382			switch (afdl[i].a_af) {
383			case AF_INET:
384				v4a = ntohl(((struct in_addr *)pton)->s_addr);
385				if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
386					pai->ai_flags &= ~AI_CANONNAME;
387				v4a >>= IN_CLASSA_NSHIFT;
388				if (v4a == 0 || v4a == IN_LOOPBACKNET)
389					pai->ai_flags &= ~AI_CANONNAME;
390				break;
391#ifdef INET6
392			case AF_INET6:
393				pfx = ((struct in6_addr *)pton)->s6_addr[0];
394				if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
395					pai->ai_flags &= ~AI_CANONNAME;
396				break;
397#endif
398			}
399
400			if (pai->ai_family == afdl[i].a_af ||
401			    pai->ai_family == PF_UNSPEC) {
402				if (! (pai->ai_flags & AI_CANONNAME)) {
403					GET_AI(top, &afdl[i], pton, port);
404					goto good;
405				}
406				/*
407				 * if AI_CANONNAME and if reverse lookup
408				 * fail, return ai anyway to pacify
409				 * calling application.
410				 *
411				 * XXX getaddrinfo() is a name->address
412				 * translation function, and it looks strange
413				 * that we do addr->name translation here.
414				 */
415				get_name(pton, &afdl[i], &top, pton, pai, port);
416				goto good;
417			} else
418				ERR(EAI_FAMILY);	/*xxx*/
419		}
420	}
421
422	if (pai->ai_flags & AI_NUMERICHOST)
423		ERR(EAI_NONAME);
424
425	/* hostname as alphabetical name */
426	error = get_addr(hostname, pai->ai_family, &top, pai, port);
427	if (error == 0) {
428		if (top) {
429 good:
430			*res = top;
431			return SUCCESS;
432		} else
433			error = EAI_FAIL;
434	}
435 free:
436	if (top)
437		freeaddrinfo(top);
438 bad:
439	*res = NULL;
440	return error;
441}
442
443static int
444get_name(addr, afd, res, numaddr, pai, port0)
445	const char *addr;
446	struct afd *afd;
447	struct addrinfo **res;
448	char *numaddr;
449	struct addrinfo *pai;
450	int port0;
451{
452	u_short port = port0 & 0xffff;
453	struct hostent *hp;
454	struct addrinfo *cur;
455	int error = 0;
456	hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
457	if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
458		GET_AI(cur, afd, hp->h_addr_list[0], port);
459		GET_CANONNAME(cur, hp->h_name);
460	} else
461		GET_AI(cur, afd, numaddr, port);
462
463	*res = cur;
464	return SUCCESS;
465 free:
466	if (cur)
467		freeaddrinfo(cur);
468
469 /* bad: */
470	*res = NULL;
471	return error;
472}
473
474static int
475get_addr(hostname, af, res0, pai, port0)
476	const char *hostname;
477	int af;
478	struct addrinfo **res0;
479	struct addrinfo *pai;
480	int port0;
481{
482	int i, error, ekeep;
483	struct addrinfo *cur;
484	struct addrinfo **res;
485	int retry;
486	int s;
487
488	res = res0;
489	ekeep = 0;
490	error = 0;
491	for (i = 0; afdl[i].a_af; i++) {
492		retry = 0;
493		if (af == AF_UNSPEC) {
494			/*
495			 * filter out AFs that are not supported by the kernel
496			 * XXX errno?
497			 */
498			s = socket(afdl[i].a_af, SOCK_DGRAM, 0);
499			if (s < 0)
500				continue;
501			close(s);
502		} else {
503			if (af != afdl[i].a_af)
504				continue;
505		}
506		/* It is WRONG, we need getipnodebyname(). */
507again:
508		error = get_addr0(hostname, afdl[i].a_af, res, pai, port0);
509		switch (error) {
510		case EAI_AGAIN:
511			if (++retry < 3)
512				goto again;
513			/* FALL THROUGH*/
514		default:
515			if (ekeep == 0)
516				ekeep = error;
517			break;
518		}
519		if (*res) {
520			/* make chain of addrs */
521			for (cur = *res;
522			     cur && cur->ai_next;
523			     cur = cur->ai_next)
524				;
525			if (!cur)
526				return EAI_FAIL;
527			res = &cur->ai_next;
528		}
529	}
530
531	/* if we got something, it's okay */
532	if (*res0)
533		return 0;
534
535	return error ? error : ekeep;
536}
537
538static int
539get_addr0(hostname, af, res, pai, port0)
540	const char *hostname;
541	int af;
542	struct addrinfo **res;
543	struct addrinfo *pai;
544	int port0;
545{
546	u_short port = port0 & 0xffff;
547	struct addrinfo sentinel;
548	struct hostent *hp;
549	struct addrinfo *top, *cur;
550	struct afd *afd;
551	int i, error = 0, h_error;
552	char *ap;
553
554	top = NULL;
555	sentinel.ai_next = NULL;
556	cur = &sentinel;
557
558#ifdef HAVE_GETHOSTBYNAME2
559	if (af == AF_UNSPEC) {
560		error = EAI_FAIL;
561		goto bad;
562	}
563	hp = gethostbyname2(hostname, af);
564#else
565	if (af != AF_UNSPEC && af != AF_INET) {
566		error = EAI_FAIL;
567		goto bad;
568	}
569	hp = gethostbyname(hostname);
570#endif
571	h_error = h_errno;
572
573	if (hp == NULL) {
574		switch (h_error) {
575		case HOST_NOT_FOUND:
576		case NO_DATA:
577			error = EAI_NODATA;
578			break;
579		case TRY_AGAIN:
580			error = EAI_AGAIN;
581			break;
582		case NO_RECOVERY:
583		case NETDB_INTERNAL:
584		default:
585			error = EAI_FAIL;
586			break;
587		}
588		goto bad;
589	}
590
591	if ((hp->h_name == NULL) || (hp->h_name[0] == 0) ||
592	    (hp->h_addr_list[0] == NULL))
593		ERR(EAI_FAIL);
594
595	for (i = 0; (ap = hp->h_addr_list[i]) != NULL; i++) {
596		switch (af) {
597#ifdef INET6
598		case AF_INET6:
599			afd = &afdl[N_INET6];
600			break;
601#endif
602#ifndef INET6
603		default:	/* AF_UNSPEC */
604#endif
605		case AF_INET:
606			afd = &afdl[N_INET];
607			break;
608#ifdef INET6
609		default:	/* AF_UNSPEC */
610			if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
611				ap += sizeof(struct in6_addr) -
612					sizeof(struct in_addr);
613				afd = &afdl[N_INET];
614			} else
615				afd = &afdl[N_INET6];
616			break;
617#endif
618		}
619		GET_AI(cur->ai_next, afd, ap, port);
620		if (cur == &sentinel) {
621			top = cur->ai_next;
622			GET_CANONNAME(top, hp->h_name);
623		}
624		cur = cur->ai_next;
625	}
626	*res = top;
627	return SUCCESS;
628 free:
629	if (top)
630		freeaddrinfo(top);
631 bad:
632	*res = NULL;
633	return error;
634}
635