getnameinfo.c 10.1 KB
Newer Older
Matthias Andree's avatar
Matthias Andree committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73
/*	$KAME: getnameinfo.c,v 1.72 2005/01/13 04:12:03 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Issues to be discussed:
 * - RFC2553 says that we should raise error on short buffer.  X/Open says
 *   we need to truncate the result.  We obey RFC2553 (and X/Open should be
 *   modified).  ipngwg rough consensus seems to follow RFC2553.  RFC3493 says
 *   nothing about it, but defines a new error code EAI_OVERFLOW which seems
 *   to be intended the code for this case.
 * - What is "local" in NI_NOFQDN?  (see comments in the code)
 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
 *   sin6_scope_id is filled - standardization status?
 * - what should we do if we should do getservbyport("sctp")?
 */

/*
 * Considerations about thread-safeness
 *   The code in this file is thread-safe, and so the thread-safeness of
 *   getnameinfo() depends on the property of backend functions.
 *     - getservbyport() is not thread safe for most systems we are targeting.
 *     - getipnodebyaddr() is thread safe.  However, many resolver libraries
 *       used in the function are not thread safe.
 *     - gethostbyaddr() is usually not thread safe.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifndef HAVE_GETNAMEINFO

#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include <string.h>
#include <stddef.h>
#include <errno.h>

74
#ifdef HAVE_INTTYPES_H
Matthias Andree's avatar
Matthias Andree committed
75
#include <inttypes.h>
76
#endif
Matthias Andree's avatar
Matthias Andree committed
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288
#include "fetchmail.h"
#include "getaddrinfo.h"

static const struct afd {
	int a_af;
	int a_addrlen;
	int a_socklen;
	int a_off;
	int a_portoff;
} afdl [] = {
#ifdef INET6
	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
	 offsetof(struct sockaddr_in6, sin6_addr),
	 offsetof(struct sockaddr_in6, sin6_port)},
#endif
	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
	 offsetof(struct sockaddr_in, sin_addr),
	 offsetof(struct sockaddr_in, sin_port)},
	{0, 0, 0, 0, 0},
};

#ifdef INET6
static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
				 size_t, int));
static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, int));
#endif

int
getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
	const struct sockaddr *sa;
#ifdef HAVE_SOCKLEN_T
	socklen_t salen;
#else
	unsigned int salen;
#endif
	char *host;
	size_t hostlen;
	char *serv;
	size_t servlen;
	int flags;
{
	const struct afd *afd;
	struct servent *sp;
	struct hostent *hp;
	u_short port;
	int family, i;
	const char *addr;
	u_int32_t v4a;
	int h_error;
	char numserv[512];
	char numaddr[512];

	if (sa == NULL)
		return EAI_FAIL;

#ifdef HAVE_SA_LEN	/*XXX*/
	if (sa->sa_len != salen)
		return EAI_FAIL;
#endif

	family = sa->sa_family;
	for (i = 0; afdl[i].a_af; i++)
		if (afdl[i].a_af == family) {
			afd = &afdl[i];
			goto found;
		}
	return EAI_FAMILY;

 found:
	if (salen != afd->a_socklen)
		return EAI_FAIL;

	/* network byte order */
	memcpy(&port, (const char *)sa + afd->a_portoff, sizeof(port));
	addr = (const char *)sa + afd->a_off;

	if (serv == NULL || servlen == 0) {
		/*
		 * do nothing in this case.
		 * in case you are wondering if "&&" is more correct than
		 * "||" here: RFC3493 says that serv == NULL OR servlen == 0
		 * means that the caller does not want the result.
		 */
	} else {
		if (flags & NI_NUMERICSERV)
			sp = NULL;
		else {
			sp = getservbyport(port,
				(flags & NI_DGRAM) ? "udp" : "tcp");
		}
		if (sp) {
			if (strlen(sp->s_name) + 1 > servlen)
				return EAI_OVERFLOW;
			strlcpy(serv, sp->s_name, servlen);
		} else {
			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
			if (strlen(numserv) + 1 > servlen)
				return EAI_OVERFLOW;
			strlcpy(serv, numserv, servlen);
		}
	}

	switch (sa->sa_family) {
	case AF_INET:
		v4a = (u_int32_t)
		    ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr);
		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
			flags |= NI_NUMERICHOST;
		v4a >>= IN_CLASSA_NSHIFT;
		if (v4a == 0)
			flags |= NI_NUMERICHOST;
		break;
#ifdef INET6
	case AF_INET6:
	    {
		const struct sockaddr_in6 *sin6;
		sin6 = (const struct sockaddr_in6 *)sa;
		switch (sin6->sin6_addr.s6_addr[0]) {
		case 0x00:
			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
				;
			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
				;
			else
				flags |= NI_NUMERICHOST;
			break;
		default:
			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
				flags |= NI_NUMERICHOST;
			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
				flags |= NI_NUMERICHOST;
			break;
		}
	    }
		break;
#endif
	}
	if (host == NULL || hostlen == 0) {
		/*
		 * do nothing in this case.
		 * in case you are wondering if "&&" is more correct than
		 * "||" here: RFC3493 says that host == NULL or hostlen == 0
		 * means that the caller does not want the result.
		 */
	} else if (flags & NI_NUMERICHOST) {
		/* NUMERICHOST and NAMEREQD conflicts with each other */
		if (flags & NI_NAMEREQD)
			return EAI_NONAME;

		goto numeric;
	} else {
#ifdef USE_GETIPNODEBY
		hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
#else
		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
#ifdef HAVE_H_ERRNO
		h_error = h_errno;
#else
		h_error = EINVAL;
#endif
#endif

		if (hp) {
#if 0
			if (flags & NI_NOFQDN) {
				/*
				 * According to RFC3493 section 6.2, NI_NOFQDN
				 * means "node name portion of the FQDN shall
				 * be returned for local hosts."  The following
				 * code tries to implement it by returning the
				 * first label (the part before the first
				 * period) of the FQDN.  However, it is not
				 * clear if this always makes sense, since the
				 * given address may be outside of "local
				 * hosts."  Due to the unclear description, we
				 * disable the code in this implementation.
				 */
				char *p;
				p = strchr(hp->h_name, '.');
				if (p)
					*p = '\0';
			}
#endif
			if (strlen(hp->h_name) + 1 > hostlen) {
#ifdef USE_GETIPNODEBY
				freehostent(hp);
#endif
				return EAI_OVERFLOW;
			}
			strlcpy(host, hp->h_name, hostlen);
#ifdef USE_GETIPNODEBY
			freehostent(hp);
#endif
		} else {
			if (flags & NI_NAMEREQD)
				return EAI_NONAME;

		  numeric:
			switch(afd->a_af) {
#ifdef INET6
			case AF_INET6:
			{
				int error;

				if ((error = ip6_parsenumeric(sa, addr, host,
							      hostlen,
							      flags)) != 0)
					return(error);
				break;
			}
#endif
			default:
289
#ifdef HAVE_INET_NTOP
Matthias Andree's avatar
Matthias Andree committed
290 291 292
				if (inet_ntop(afd->a_af, addr, host,
				    hostlen) == NULL)
					return EAI_SYSTEM;
293
#else
294 295 296 297 298
				if (afd->a_af == AF_INET) {
				    struct in_addr addr_tmp;
				    addr_tmp.s_addr = addr;
				    strlcpy(host, inet_ntoa(addr_tmp), hostlen);
				}
299 300 301
				else
				    return EAI_FAMILY;
#endif
Matthias Andree's avatar
Matthias Andree committed
302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392
				break;
			}
		}
	}
	return(0);
}

#ifdef INET6
static int
ip6_parsenumeric(sa, addr, host, hostlen, flags)
	const struct sockaddr *sa;
	const char *addr;
	char *host;
	size_t hostlen;
	int flags;
{
	int numaddrlen;
	char numaddr[512];

	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
		return EAI_SYSTEM;

	numaddrlen = strlen(numaddr);
	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
		return EAI_OVERFLOW;
	strlcpy(host, numaddr, hostlen);

	if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
		char zonebuf[MAXHOSTNAMELEN];
		int zonelen;

		zonelen = ip6_sa2str(
		    (const struct sockaddr_in6 *)(const void *)sa,
		    zonebuf, sizeof(zonebuf), flags);
		if (zonelen < 0)
			return EAI_OVERFLOW;
		if (zonelen + 1 + numaddrlen + 1 > hostlen)
			return EAI_OVERFLOW;

		/* construct <numeric-addr><delim><zoneid> */
		memcpy(host + numaddrlen + 1, zonebuf,
		    (size_t)zonelen);
		host[numaddrlen] = SCOPE_DELIMITER;
		host[numaddrlen + 1 + zonelen] = '\0';
	}

	return 0;
}

/* ARGSUSED */
static int
ip6_sa2str(sa6, buf, bufsiz, flags)
	const struct sockaddr_in6 *sa6;
	char *buf;
	size_t bufsiz;
	int flags;
{
	unsigned int ifindex;
	const struct in6_addr *a6;
	int n;

	ifindex = (unsigned int)sa6->sin6_scope_id;
	a6 = &sa6->sin6_addr;

#ifdef NI_NUMERICSCOPE
	if ((flags & NI_NUMERICSCOPE) != 0) {
		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
		if (n < 0 || n >= bufsiz)
			return -1;
		else
			return n;
	}
#endif

	/* if_indextoname() does not take buffer size.  not a good api... */
	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) ||
	     IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) {
		char *p = if_indextoname(ifindex, buf);
		if (p)
			return (strlen(p));
	}

	/* last resort */
	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
	if (n < 0 || n >= bufsiz)
		return -1;
	else
		return n;
}
#endif /* INET6 */
#endif