xref: /illumos-gate/usr/src/lib/libsocket/inet/getaddrinfo.c (revision aa1e129cc24759a40c3f60101674aeadbe9287a4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Copyright 2023 Oxide Computer Company
29  */
30 
31 #include <netdb.h>
32 #include <arpa/inet.h>
33 #include <nss_dbdefs.h>
34 #include <netinet/in.h>
35 #include <sys/debug.h>
36 #include <sys/socket.h>
37 #include <string.h>
38 #include <strings.h>
39 #include <stdio.h>
40 #include <ctype.h>
41 #include <sys/types.h>
42 #include <stdlib.h>
43 #include <libintl.h>
44 #include <net/if.h>
45 
46 #define	ai2sin(x)	((struct sockaddr_in *)((x)->ai_addr))
47 #define	ai2sin6(x)	((struct sockaddr_in6 *)((x)->ai_addr))
48 
49 #define	HOST_BROADCAST	"255.255.255.255"
50 
51 /*
52  * getaddrinfo() returns EAI_NONAME in some cases, however since EAI_NONAME is
53  * not part of SUSv3 it needed to be masked in the standards compliant
54  * environment. GAIV_DEFAULT and GAIV_XPG6 accomplish this.
55  */
56 #define	GAIV_DEFAULT	0
57 #define	GAIV_XPG6	1
58 
59 /*
60  * Storage allocation for global variables in6addr_any and in6addr_loopback.
61  * The extern declarations for these variables are defined in <netinet/in.h>.
62  * These two variables could have been defined in any of the "C" files in
63  * libsocket. They are defined here with other IPv6 related interfaces.
64  */
65 const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
66 const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
67 
68 /* AI_MASK:  all valid flags for addrinfo */
69 #define	AI_MASK		(AI_PASSIVE | AI_CANONNAME | AI_NUMERICHOST \
70 	| AI_ADDRCONFIG | AI_NUMERICSERV | AI_V4MAPPED | AI_ALL)
71 #define	ANY		0
72 
73 /*
74  * This is a private, undocumented, flag that getaddrinfo() uses for
75  * getipnodebyname(). In the case of AI_ADDRCONFIG && AI_V4MAPPED, if there are
76  * no IPv6 addresses, getaddrinfo() should return non-IPv4 mapped addresses. On
77  * the flip side, getipnodebyname() is defined by RFC 2553 to explicitly do so.
78  * Therefore this private flag indicates to getaddrinfo that we shouldn't do
79  * this.
80  */
81 #define	AI_ADDRINFO	0x8000
82 
83 typedef struct {
84 	int		si_socktype;
85 	int		si_protocol;
86 	ushort_t	si_port;
87 } spinfo_t;
88 
89 /* function prototypes for used by getaddrinfo() routine */
90 static int get_addr(int, const char *, struct addrinfo *,
91 	struct addrinfo *, spinfo_t *, uint_t, int);
92 static uint_t getscopeidfromzone(const struct sockaddr_in6 *,
93     const char *, uint32_t *);
94 static void servtype(const char *, int *, int *);
95 static boolean_t str_isnumber(const char *);
96 
97 /*
98  * getaddrinfo:
99  *
100  * Purpose:
101  *   Routine for performing Address-to-nodename in a protocol-independent
102  *   fashion.
103  * Description and history of the routine:
104  *   Nodename-to-address translation is done in a protocol- independent fashion
105  *   using the getaddrinfo() function that is taken from IEEE POSIX 1003.1g.
106  *
107  *   The official specification for this function will be the final POSIX
108  *   standard, with the following additional requirements:
109  *
110  *   - getaddrinfo() must be thread safe
111  *   - The AI_NUMERICHOST is new.
112  *   - All fields in socket address structures returned by getaddrinfo() that
113  *     are not filled in through an explicit argument (e.g., sin6_flowinfo and
114  *     sin_zero) must be set to 0. (This makes it easier to compare socket
115  *     address structures).
116  *
117  * Input Parameters:
118  *
119  *   nodename       - pointer to a null-terminated string that represents
120  *                    a hostname or literal ip address (IPv4/IPv6), or this
121  *                    pointer can be NULL.
122  *   servname       - pointer to a null-terminated string that represents
123  *                    a servicename or literal port number, or this
124  *                    pointer can be NULL.
125  *   hints          - optional argument that points to an addrinfo structure
126  *                    to provide hints on the type of socket that the caller
127  *                    supports.
128  *
129  * Possible setting of the ai_flags member of the hints structure:
130  *
131  *   AI_PASSIVE     - If set, the caller plans to use the returned socket
132  *                    address in a call to bind().  In this case, it the
133  *                    nodename argument is NULL, then the IP address portion
134  *                    of the socket address structure will be set to
135  *                    INADDR_ANY for IPv4 or IN6ADDR_ANY_INIT for IPv6.
136  *                    If not set, then the returned socket address will be
137  *                    ready for a call to connect() (for conn-oriented) or
138  *                    connect(), sendto(), or sendmsg() (for connectionless).
139  *                    In this case, if nodename is NULL, then the IP address
140  *                    portion of the socket address structure will be set to
141  *                    the loopback address.
142  *   AI_CANONNAME   - If set, then upon successful return the ai_canonname
143  *                    field of the first addrinfo structure in the linked
144  *                    list will point to a NULL-terminated string
145  *                    containing the canonical name of the specified nodename.
146  *   AI_NUMERICHOST - If set, then a non-NULL nodename string must be a numeric
147  *                    host address string.  Otherwise an error of EAI_NONAME
148  *                    is returned.  This flag prevents any type of name
149  *                    resolution service from being called.
150  *   AI_NUMERICSERV - If set, then a non-null servname string supplied shall
151  *                    be a numeric port string. Otherwise, an [EAI_NONAME]
152  *                    error shall be returned. This flag shall prevent any
153  *                    type of name resolution service from being invoked.
154  *   AI_ADDRCONFIG  - If set, IPv4 addresses are returned only if an IPv4
155  *                    address is configured on the local system, and IPv6
156  *                    addresses are returned only if an IPv6 address is
157  *                    configured on the local system.
158  *   AI_V4MAPPED    - If set, along with an ai_family of AF_INET6, then
159  *                    getaddrinfo() shall return IPv4-mapped IPv6 addresses
160  *                    on finding no matching IPv6 addresses (ai_addrlen shall
161  *                    be 16). The AI_V4MAPPED flag shall be ignored unless
162  *                    ai_family equals AF_INET6.
163  *   AI_ALL         - If the AI_ALL flag is used with the AI_V4MAPPED flag,
164  *		      then getaddrinfo() shall return all matching IPv6 and
165  *		      IPv4 addresses. The AI_ALL flag without the AI_V4MAPPED
166  *		      flag is ignored.
167  *
168  * Output Parameters:
169  *
170  *   res            - upon successful return a pointer to a linked list of one
171  *                    or more addrinfo structures is returned through this
172  *                    argument.  The caller can process each addrinfo structures
173  *                    in this list by following the ai_next pointer, until a
174  *                    NULL pointer is encountered.  In each returned addrinfo
175  *                    structure the three members ai_family, ai_socktype, and
176  *                    ai_protocol are corresponding arguments for a call to the
177  *                    socket() function.  In each addrinfo structure the ai_addr
178  *                    field points to filled-in socket address structure whose
179  *                    length is specified by the ai_addrlen member.
180  *
181  * Return Value:
182  *  This function returns 0 upon success or a nonzero error code.  The
183  *  following names are nonzero error codes from getaddrinfo(), and are
184  *  defined in <netdb.h>.
185  *      EAI_ADDRFAMILY - address family not supported
186  *      EAI_AGAIN      - DNS temporary failure
187  *      EAI_BADFLAGS   - invalid ai_flags
188  *      EAI_FAIL       - DNS non-recoverable failure
189  *      EAI_FAMILY     - ai_family not supported
190  *      EAI_MEMORY     - memory allocation failure
191  *      EAI_NODATA     - no address associated with nodename
192  *      EAI_NONAME     - host/servname not known
193  *      EAI_SERVICE    - servname not supported for ai_socktype
194  *      EAI_SOCKTYPE   - ai_socktype not supported
195  *      EAI_SYSTEM     - system error in errno
196  *
197  * Memory Allocation:
198  *  All of the information returned by getaddrinfo() is dynamically
199  *  allocated:  the addrinfo structures, and the socket address
200  *  structures and canonical node name strings pointed to by the
201  *  addrinfo structures.
202  */
203 
204 static int
205 _getaddrinfo(const char *hostname, const char *servname,
206     const struct addrinfo *hints, struct addrinfo **res, int version)
207 {
208 	struct addrinfo *cur;
209 	struct addrinfo *aip;
210 	struct addrinfo ai;
211 	int error;
212 
213 	/*
214 	 * We currently accumulate three services in the
215 	 * SOCKTYPE_ANY/AI_NUMERICSERV case and one otherwise. If the logic in
216 	 * this function is extended to return all matches from the services
217 	 * database when AI_NUMERICSERV is not specified, this will need
218 	 * revisiting.
219 	 */
220 #define	SPINFO_SIZE 3
221 	spinfo_t spinfo[SPINFO_SIZE];
222 	uint_t spidx = 0;
223 	/* Note that these macros require spinfo and spidx to be in scope */
224 #define	SP_ADDX(type, proto, port) \
225 	do { \
226 		ASSERT3U(spidx, <, SPINFO_SIZE); \
227 		spinfo[spidx].si_socktype = (type); \
228 		spinfo[spidx].si_protocol = (proto); \
229 		spinfo[spidx].si_port = (port); \
230 		spidx++; \
231 	} while (0)
232 #define	SP_ADD(sp) \
233 	do { \
234 		int _type, _proto; \
235 		servtype((sp)->s_proto, &_type, &_proto); \
236 		SP_ADDX(_type, _proto, (sp)->s_port); \
237 	} while (0)
238 
239 	*res = NULL;
240 
241 	if (hostname == NULL && servname == NULL)
242 		return (EAI_NONAME);
243 
244 	cur = &ai;
245 	aip = &ai;
246 
247 	if (hints == NULL) {
248 		aip->ai_flags = 0;
249 		aip->ai_family = PF_UNSPEC;
250 		aip->ai_socktype = ANY;
251 		aip->ai_protocol = ANY;
252 	} else {
253 		(void) memcpy(aip, hints, sizeof (*aip));
254 
255 		/* check for bad flags in hints */
256 		if (hints->ai_flags != 0 && (hints->ai_flags & ~AI_MASK))
257 			return (EAI_BADFLAGS);
258 
259 		if ((hostname == NULL || *hostname == '\0') &&
260 		    (hints->ai_flags & AI_CANONNAME)) {
261 			return (EAI_BADFLAGS);
262 		}
263 
264 		if (hints->ai_family != PF_UNSPEC &&
265 		    hints->ai_family != PF_INET &&
266 		    hints->ai_family != PF_INET6) {
267 			return (EAI_FAMILY);
268 		}
269 
270 		switch (aip->ai_socktype) {
271 		case ANY:
272 			switch (aip->ai_protocol) {
273 			case ANY:
274 				break;
275 			case IPPROTO_UDP:
276 				aip->ai_socktype = SOCK_DGRAM;
277 				break;
278 			case IPPROTO_TCP:
279 			case IPPROTO_SCTP:
280 				aip->ai_socktype = SOCK_STREAM;
281 				break;
282 			default:
283 				aip->ai_socktype = SOCK_RAW;
284 				break;
285 			}
286 			break;
287 		case SOCK_RAW:
288 			break;
289 		case SOCK_SEQPACKET:
290 			/*
291 			 * If the hint does not have a preference on the
292 			 * protocol, use SCTP as the default for
293 			 * SOCK_SEQPACKET.
294 			 */
295 			if (aip->ai_protocol == ANY)
296 				aip->ai_protocol = IPPROTO_SCTP;
297 			break;
298 		case SOCK_DGRAM:
299 			aip->ai_protocol = IPPROTO_UDP;
300 			break;
301 		case SOCK_STREAM:
302 			/*
303 			 * If the hint does not have a preference on the
304 			 * protocol, use TCP as the default for SOCK_STREAM.
305 			 */
306 			if (aip->ai_protocol == ANY)
307 				aip->ai_protocol = IPPROTO_TCP;
308 			break;
309 		default:
310 			return (EAI_SOCKTYPE);
311 		}
312 	}
313 
314 	aip->ai_addrlen = 0;
315 	aip->ai_canonname = NULL;
316 	aip->ai_addr = NULL;
317 	aip->ai_next = NULL;
318 #ifdef __sparcv9
319 	/*
320 	 * We need to clear _ai_pad to preserve binary compatibility with
321 	 * previously compiled 64-bit applications by guaranteeing the upper
322 	 * 32-bits are empty.
323 	 */
324 	aip->_ai_pad = 0;
325 #endif /* __sparcv9 */
326 
327 	/*
328 	 * Get the service.
329 	 */
330 
331 	if (servname != NULL) {
332 		struct servent result;
333 		int bufsize = 128;
334 		char *buf = NULL;
335 		struct servent *sp;
336 		const char *proto = NULL;
337 
338 		switch (aip->ai_socktype) {
339 		case ANY:
340 		case SOCK_RAW:
341 			proto = NULL;
342 			break;
343 		case SOCK_DGRAM:
344 			proto = "udp";
345 			break;
346 		case SOCK_STREAM:
347 			/*
348 			 * If there is no hint given, use TCP as the default
349 			 * protocol.
350 			 */
351 			switch (aip->ai_protocol) {
352 			case ANY:
353 			case IPPROTO_TCP:
354 			default:
355 				proto = "tcp";
356 				break;
357 			case IPPROTO_SCTP:
358 				proto = "sctp";
359 				break;
360 			}
361 			break;
362 		case SOCK_SEQPACKET:
363 			/* Default to SCTP if no hint given. */
364 			switch (aip->ai_protocol) {
365 			case ANY:
366 			default:
367 				proto = "sctp";
368 				break;
369 			}
370 			break;
371 		}
372 		/*
373 		 * Servname string can be a decimal port number.
374 		 */
375 		if (str_isnumber(servname)) {
376 			ushort_t port = htons(atoi(servname));
377 
378 			if (aip->ai_socktype == ANY) {
379 				/*
380 				 * The socket type is not known so we return
381 				 * one result for each of these types.
382 				 */
383 				SP_ADDX(SOCK_STREAM, IPPROTO_TCP, port);
384 				SP_ADDX(SOCK_DGRAM, IPPROTO_UDP, port);
385 				SP_ADDX(SOCK_STREAM, IPPROTO_SCTP, port);
386 			} else {
387 				/*
388 				 * If we know the socket type then we can
389 				 * return it.
390 				 */
391 				SP_ADDX(aip->ai_socktype, aip->ai_protocol,
392 				    port);
393 			}
394 		} else if (aip->ai_flags & AI_NUMERICSERV) {
395 			/*
396 			 * The AI_NUMERICSERV flag was specified, but the
397 			 * servname is not a decimal number so we fail.
398 			 */
399 			return (EAI_NONAME);
400 		} else {
401 			/*
402 			 * Look up the provided service name in the service
403 			 * database.
404 			 */
405 			do {
406 				buf = reallocf(buf, bufsize);
407 				if (buf == NULL)
408 					return (EAI_MEMORY);
409 
410 				sp = getservbyname_r(servname, proto, &result,
411 				    buf, bufsize);
412 				if (sp == NULL && errno != ERANGE) {
413 					free(buf);
414 					return (EAI_SERVICE);
415 				}
416 				/*
417 				 * errno == ERANGE so our scratch buffer space
418 				 * wasn't big enough.  Double it and try again.
419 				 */
420 				bufsize *= 2;
421 			} while (sp == NULL);
422 			if (aip->ai_socktype != ANY) {
423 				SP_ADDX(aip->ai_socktype, aip->ai_protocol,
424 				    sp->s_port);
425 			} else {
426 				SP_ADD(sp);
427 			}
428 		}
429 		free(buf);
430 
431 		if (spidx == 0)
432 			return (EAI_SERVICE);
433 	} else {
434 		SP_ADDX(aip->ai_socktype, aip->ai_protocol, 0);
435 	}
436 
437 	error = get_addr(aip->ai_family, hostname, aip, cur,
438 	    spinfo, spidx, version);
439 
440 	if (error != 0) {
441 		if (aip->ai_next != NULL)
442 			freeaddrinfo(aip->ai_next);
443 		return (error);
444 	}
445 
446 	*res = aip->ai_next;
447 	return (0);
448 }
449 #undef SP_ADD
450 #undef SP_ADDX
451 
452 int
453 getaddrinfo(const char *hostname, const char *servname,
454     const struct addrinfo *hints, struct addrinfo **res)
455 {
456 	return (_getaddrinfo(hostname, servname, hints, res, GAIV_DEFAULT));
457 }
458 
459 int
460 __xnet_getaddrinfo(const char *hostname, const char *servname,
461     const struct addrinfo *hints, struct addrinfo **res)
462 {
463 	return (_getaddrinfo(hostname, servname, hints, res, GAIV_XPG6));
464 }
465 
466 static int
467 add_address4(struct addrinfo *aip, struct addrinfo **cur,
468     struct in_addr *addr, const char *canonname, spinfo_t *info)
469 {
470 	struct addrinfo *nai;
471 	int addrlen;
472 
473 	nai = malloc(sizeof (struct addrinfo));
474 	if (nai == NULL)
475 		return (EAI_MEMORY);
476 
477 	*nai = *aip;
478 	nai->ai_next = NULL;
479 	addrlen = sizeof (struct sockaddr_in);
480 
481 	nai->ai_addr = malloc(addrlen);
482 	if (nai->ai_addr == NULL) {
483 		freeaddrinfo(nai);
484 		return (EAI_MEMORY);
485 	}
486 
487 	bzero(nai->ai_addr, addrlen);
488 	nai->ai_addrlen = addrlen;
489 	nai->ai_family = PF_INET;
490 
491 	(void) memcpy(&ai2sin(nai)->sin_addr, addr, sizeof (struct in_addr));
492 	nai->ai_canonname = NULL;
493 	if ((nai->ai_flags & AI_CANONNAME) && canonname != NULL) {
494 		canonname = strdup(canonname);
495 		if (canonname == NULL) {
496 			freeaddrinfo(nai);
497 			return (EAI_MEMORY);
498 		}
499 		nai->ai_canonname = (char *)canonname;
500 	}
501 	ai2sin(nai)->sin_family = PF_INET;
502 	ai2sin(nai)->sin_port = info->si_port;
503 	nai->ai_socktype = info->si_socktype;
504 	nai->ai_protocol = info->si_protocol;
505 
506 	(*cur)->ai_next = nai;
507 	*cur = nai;
508 
509 	return (0);
510 }
511 
512 static int
513 add_address6(struct addrinfo *aip, struct addrinfo **cur,
514     struct in6_addr *addr, const char *zonestr, const char *canonname,
515     spinfo_t *info)
516 {
517 	struct addrinfo *nai;
518 	int addrlen;
519 
520 	nai = malloc(sizeof (struct addrinfo));
521 	if (nai == NULL)
522 		return (EAI_MEMORY);
523 
524 	*nai = *aip;
525 	nai->ai_next = NULL;
526 	addrlen = sizeof (struct sockaddr_in6);
527 
528 	nai->ai_addr = malloc(addrlen);
529 	if (nai->ai_addr == NULL) {
530 		freeaddrinfo(nai);
531 		return (EAI_MEMORY);
532 	}
533 
534 	bzero(nai->ai_addr, addrlen);
535 	nai->ai_addrlen = addrlen;
536 	nai->ai_family = PF_INET6;
537 
538 	(void) memcpy(ai2sin6(nai)->sin6_addr.s6_addr,
539 	    &addr->s6_addr, sizeof (struct in6_addr));
540 	nai->ai_canonname = NULL;
541 	if ((nai->ai_flags & AI_CANONNAME) && canonname != NULL) {
542 		canonname = strdup(canonname);
543 		if (canonname == NULL) {
544 			freeaddrinfo(nai);
545 			return (EAI_MEMORY);
546 		}
547 		nai->ai_canonname = (char *)canonname;
548 	}
549 	ai2sin6(nai)->sin6_family = PF_INET6;
550 	ai2sin6(nai)->sin6_port = info->si_port;
551 	nai->ai_socktype = info->si_socktype;
552 	nai->ai_protocol = info->si_protocol;
553 
554 	/* set sin6_scope_id */
555 	if (zonestr != NULL) {
556 		/* Translate 'zonestr' into a valid sin6_scope_id. */
557 		int err = getscopeidfromzone(ai2sin6(nai), zonestr,
558 		    &ai2sin6(nai)->sin6_scope_id);
559 		if (err != 0) {
560 			freeaddrinfo(nai);
561 			return (err);
562 		}
563 	} else {
564 		ai2sin6(nai)->sin6_scope_id = 0;
565 	}
566 
567 	(*cur)->ai_next = nai;
568 	*cur = nai;
569 
570 	return (0);
571 }
572 
573 static int
574 get_addr(int family, const char *hostname, struct addrinfo *aip,
575     struct addrinfo *cur, spinfo_t *ports, uint_t nport, int version)
576 {
577 	struct hostent		*hp;
578 	char			_hostname[MAXHOSTNAMELEN];
579 	int			errnum;
580 	boolean_t		firsttime = B_TRUE;
581 	char			*zonestr = NULL;
582 	uint_t			i;
583 
584 	if (hostname == NULL) {
585 		/*
586 		 * case 1: AI_PASSIVE bit set : anyaddr 0.0.0.0 or ::
587 		 * case 2: AI_PASSIVE bit not set : localhost 127.0.0.1 or ::1
588 		 */
589 		const char *canon = "loopback";
590 		errnum = 0;
591 
592 		/*
593 		 * PF_INET gets IPv4 only, PF_INET6 gets IPv6 only.
594 		 * PF_UNSPEC gets both.
595 		 */
596 		if (family != PF_INET) {
597 			struct in6_addr v6addr;
598 
599 			if (aip->ai_flags & AI_PASSIVE) {
600 				(void) memcpy(&v6addr.s6_addr,
601 				    in6addr_any.s6_addr,
602 				    sizeof (struct in6_addr));
603 				canon = NULL;
604 			} else {
605 				(void) memcpy(&v6addr.s6_addr,
606 				    in6addr_loopback.s6_addr,
607 				    sizeof (struct in6_addr));
608 			}
609 
610 			for (i = 0; i < nport; i++) {
611 				errnum = add_address6(aip, &cur, &v6addr, NULL,
612 				    canon, &ports[i]);
613 				canon = NULL;
614 				if (errnum != 0)
615 					break;
616 			}
617 		}
618 
619 		if (errnum == 0 && family != PF_INET6) {
620 			struct in_addr addr;
621 
622 			if (aip->ai_flags & AI_PASSIVE) {
623 				addr.s_addr = INADDR_ANY;
624 				canon = NULL;
625 			} else {
626 				addr.s_addr = htonl(INADDR_LOOPBACK);
627 			}
628 
629 			for (i = 0; i < nport; i++) {
630 				errnum = add_address4(aip, &cur, &addr, canon,
631 				    &ports[i]);
632 				canon = NULL;
633 				if (errnum != 0)
634 					break;
635 			}
636 		}
637 
638 		return (errnum);
639 	}
640 
641 	/*
642 	 * Check for existence of address-zoneid delimiter '%'
643 	 * If the delimiter exists, parse the zoneid portion of
644 	 * <addr>%<zone_id>
645 	 */
646 	if ((zonestr = strchr(hostname, '%')) != NULL) {
647 		/* make sure we have room for <addr> portion of hostname */
648 		if ((zonestr - hostname) + 1 > sizeof (_hostname))
649 			return (EAI_MEMORY);
650 
651 		/* chop off and save <zone_id> portion */
652 		(void) strlcpy(_hostname, hostname, (zonestr - hostname) + 1);
653 		++zonestr;	/* make zonestr point at start of <zone-id> */
654 		/* ensure zone is valid */
655 		if (*zonestr == '\0' || strlen(zonestr) > LIFNAMSIZ)
656 			return (EAI_NONAME);
657 	} else {
658 		size_t hlen = sizeof (_hostname);
659 
660 		if (strlcpy(_hostname, hostname, hlen) >= hlen)
661 			return (EAI_MEMORY);
662 	}
663 
664 	/* Check to see if AI_NUMERICHOST bit is set */
665 	if (aip->ai_flags & AI_NUMERICHOST) {
666 		struct in6_addr v6addr;
667 
668 		/* check to see if _hostname points to a literal IP address */
669 		if (!(inet_addr(_hostname) != ((in_addr_t)-1) ||
670 		    strcmp(_hostname, HOST_BROADCAST) == 0 ||
671 		    inet_pton(AF_INET6, _hostname, &v6addr) > 0)) {
672 			return (EAI_NONAME);
673 		}
674 	}
675 
676 	/* if hostname argument is literal, name service doesn't get called */
677 	if (family == PF_UNSPEC) {
678 		hp = getipnodebyname(_hostname, AF_INET6,
679 		    AI_ALL | aip->ai_flags | AI_V4MAPPED | AI_ADDRINFO,
680 		    &errnum);
681 	} else {
682 		hp = getipnodebyname(_hostname, family, aip->ai_flags, &errnum);
683 	}
684 
685 	if (hp == NULL) {
686 		switch (errnum) {
687 		case HOST_NOT_FOUND:
688 			return (EAI_NONAME);
689 		case TRY_AGAIN:
690 			return (EAI_AGAIN);
691 		case NO_RECOVERY:
692 			return (EAI_FAIL);
693 		case NO_ADDRESS:
694 			if (version == GAIV_XPG6)
695 				return (EAI_NONAME);
696 			return (EAI_NODATA);
697 		default:
698 			return (EAI_SYSTEM);
699 		}
700 	}
701 
702 	for (i = 0; hp->h_addr_list[i]; i++) {
703 		boolean_t create_v6_addrinfo = B_TRUE;
704 		struct in_addr v4addr;
705 		struct in6_addr v6addr;
706 		uint_t j;
707 
708 		/* Determine if an IPv6 addrinfo structure should be created */
709 		if (hp->h_addrtype == AF_INET6) {
710 			struct in6_addr *v6addrp;
711 
712 			v6addrp = (struct in6_addr *)hp->h_addr_list[i];
713 			if (!(aip->ai_flags & AI_V4MAPPED) &&
714 			    IN6_IS_ADDR_V4MAPPED(v6addrp)) {
715 				create_v6_addrinfo = B_FALSE;
716 				IN6_V4MAPPED_TO_INADDR(v6addrp, &v4addr);
717 			} else {
718 				(void) memcpy(&v6addr.s6_addr,
719 				    hp->h_addr_list[i],
720 				    sizeof (struct in6_addr));
721 			}
722 		} else if (hp->h_addrtype == AF_INET) {
723 			create_v6_addrinfo = B_FALSE;
724 			(void) memcpy(&v4addr.s_addr, hp->h_addr_list[i],
725 			    sizeof (struct in_addr));
726 		} else {
727 			return (EAI_SYSTEM);
728 		}
729 
730 		for (j = 0; j < nport; j++) {
731 			if (create_v6_addrinfo) {
732 				errnum = add_address6(aip, &cur, &v6addr,
733 				    zonestr, firsttime ? hp->h_name : NULL,
734 				    &ports[j]);
735 			} else {
736 				errnum = add_address4(aip, &cur, &v4addr,
737 				    firsttime ? hp->h_name : NULL,
738 				    &ports[j]);
739 			}
740 			firsttime = B_FALSE;
741 			if (errnum != 0) {
742 				freehostent(hp);
743 				return (errnum);
744 			}
745 		}
746 	}
747 	freehostent(hp);
748 	return (0);
749 }
750 
751 /*
752  * getscopeidfromzone(sa, zone, sin6_scope_id)
753  *
754  * Converts the string pointed to by 'zone' into a sin6_scope_id.
755  * 'zone' will either be a pointer to an interface name or will
756  * be a literal sin6_scope_id.
757  *
758  * 0 is returned on success and the output parameter 'sin6_scope_id' will
759  *   be set to a valid sin6_scope_id.
760  * EAI_NONAME is returned for either of two reasons:
761  *	1.  The IPv6 address pointed to by sa->sin6_addr is not
762  *	    part of the 'link scope' (ie link local, nodelocal multicast or
763  *	    linklocal multicast address)
764  *	2.  The string pointed to by 'zone' can not be translate to a valid
765  *	    sin6_scope_id.
766  */
767 static uint_t
768 getscopeidfromzone(const struct sockaddr_in6 *sa, const char *zone,
769     uint32_t *sin6_scope_id)
770 {
771 	const in6_addr_t *addr = &sa->sin6_addr;
772 	ulong_t ul_scope_id;
773 	char *endp;
774 
775 	if (IN6_IS_ADDR_LINKSCOPE(addr)) {
776 		/*
777 		 * Look up interface index associated with interface name
778 		 * pointed to by 'zone'.  Since the address is part of the link
779 		 * scope, there is a one-to-one relationship between interface
780 		 * index and sin6_scope_id.
781 		 * If an interface index can not be found for 'zone', then
782 		 * treat 'zone' as a literal sin6_scope_id value.
783 		 */
784 		if ((*sin6_scope_id = if_nametoindex(zone)) != 0) {
785 			return (0);
786 		} else {
787 			if ((ul_scope_id = strtoul(zone, &endp, 10)) != 0) {
788 				/* check that entire string was read */
789 				if (*endp != '\0') {
790 					return (EAI_NONAME);
791 				}
792 				*sin6_scope_id =
793 				    (uint32_t)(ul_scope_id & 0xffffffffUL);
794 			} else {
795 				return (EAI_NONAME);
796 			}
797 		}
798 	} else {
799 		return (EAI_NONAME);
800 	}
801 	return (0);
802 }
803 
804 void
805 freeaddrinfo(struct addrinfo *ai)
806 {
807 	struct addrinfo *next;
808 
809 	do {
810 		next = ai->ai_next;
811 		free(ai->ai_canonname);
812 		free(ai->ai_addr);
813 		free(ai);
814 		ai = next;
815 	} while (ai != NULL);
816 }
817 
818 static void
819 servtype(const char *tag, int *type, int *proto)
820 {
821 	*type = *proto = 0;
822 	if (strcmp(tag, "udp") == 0) {
823 		*type = SOCK_DGRAM;
824 		*proto = IPPROTO_UDP;
825 	} else if (strcmp(tag, "tcp") == 0) {
826 		*type = SOCK_STREAM;
827 		*proto = IPPROTO_TCP;
828 	} else if (strcmp(tag, "sctp") == 0) {
829 		*type = SOCK_STREAM;
830 		*proto = IPPROTO_SCTP;
831 	}
832 }
833 
834 static boolean_t
835 str_isnumber(const char *p)
836 {
837 	char *q = (char *)p;
838 	while (*q != '\0') {
839 		if (!isdigit(*q))
840 			return (B_FALSE);
841 		q++;
842 	}
843 	return (B_TRUE);
844 }
845 
846 static const char *gai_errlist[] = {
847 	"name translation error 0 (no error)",		/* 0 */
848 	"specified address family not supported",	/* 1 EAI_ADDRFAMILY */
849 	"temporary name resolution failure",		/* 2 EAI_AGAIN */
850 	"invalid flags",				/* 3 EAI_BADFLAGS */
851 	"non-recoverable name resolution failure",	/* 4 EAI_FAIL */
852 	"specified address family not supported",	/* 5 EAI_FAMILY */
853 	"memory allocation failure",			/* 6 EAI_MEMORY */
854 	"no address for the specified node name",	/* 7 EAI_NODATA */
855 	"node name or service name not known",		/* 8 EAI_NONAME */
856 	"service name not available for the specified socket type",
857 							/* 9 EAI_SERVICE */
858 	"specified socket type not supported",		/* 10 EAI_SOCKTYPE */
859 	"system error",					/* 11 EAI_SYSTEM */
860 };
861 static int gai_nerr = { sizeof (gai_errlist)/sizeof (gai_errlist[0]) };
862 
863 const char *
864 gai_strerror(int ecode)
865 {
866 	if (ecode < 0)
867 		return (dgettext(TEXT_DOMAIN,
868 		    "name translation internal error"));
869 	else if (ecode < gai_nerr)
870 		return (dgettext(TEXT_DOMAIN, gai_errlist[ecode]));
871 	return (dgettext(TEXT_DOMAIN, "unknown name translation error"));
872 }
873