lib/libc/net/getnameinfo.c

   1 /*      $NetBSD: getnameinfo.c,v 1.46 2009/02/11 05:25:17 lukem Exp $   */
   2 /*      $KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $    */
   3
   4 /*
   5  * Copyright (c) 2000 Ben Harris.
   6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Issues to be discussed:
  36  * - Thread safe-ness must be checked
  37  * - RFC2553 says that we should raise error on short buffer.  X/Open says
  38  *   we need to truncate the result.  We obey RFC2553 (and X/Open should be
  39  *   modified).  ipngwg rough consensus seems to follow RFC2553.
  40  * - What is "local" in NI_FQDN?
  41  * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
  42  * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
  43  *   sin6_scope_id is filled - standardization status?
  44  *   XXX breaks backward compat for code that expects no scopeid.
  45  *   beware on merge.
  46  */
  47
  48 #include <sys/cdefs.h>
  49 #if defined(LIBC_SCCS) && !defined(lint)
  50 __RCSID("$NetBSD: getnameinfo.c,v 1.46 2009/02/11 05:25:17 lukem Exp $");
  51 #endif /* LIBC_SCCS and not lint */
  52
  53 #include "namespace.h"
  54 #include <sys/types.h>
  55 #include <sys/socket.h>
  56 #include <net/if.h>
  57 #include <net/if_dl.h>
  58 #include <net/if_ieee1394.h>
  59 #include <net/if_types.h>
  60 #include <netinet/in.h>
  61 #include <arpa/inet.h>
  62 #include <arpa/nameser.h>
  63 #include <assert.h>
  64 #include <limits.h>
  65 #include <netdb.h>
  66 #include <resolv.h>
  67 #include <stddef.h>
  68 #include <string.h>
  69
  70 #include "servent.h"
  71
  72 #ifdef __weak_alias
  73 __weak_alias(getnameinfo,_getnameinfo)
  74 #endif
  75
  76 static const struct afd {
  77         int             a_af;
  78         socklen_t       a_addrlen;
  79         socklen_t       a_socklen;
  80         int             a_off;
  81 } afdl [] = {
  82 #ifdef INET6
  83         {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
  84                 offsetof(struct sockaddr_in6, sin6_addr)},
  85 #endif
  86         {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
  87                 offsetof(struct sockaddr_in, sin_addr)},
  88         {0, 0, 0, 0},
  89 };
  90
  91 struct sockinet {
  92         u_char  si_len;
  93         u_char  si_family;
  94         u_short si_port;
  95 };
  96
  97 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
  98     socklen_t, char *, socklen_t, int));
  99 #ifdef INET6
 100 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
 101                                  socklen_t, int));
 102 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t,
 103                                  int));
 104 #endif
 105 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
 106     socklen_t, char *, socklen_t, int));
 107 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
 108
 109 /*
 110  * Top-level getnameinfo() code.  Look at the address family, and pick an
 111  * appropriate function to call.
 112  */
 113 int
 114 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 115         const struct sockaddr *sa;
 116         socklen_t salen;
 117         char *host, *serv;
 118         socklen_t hostlen, servlen;
 119         int flags;
 120 {
 121
 122         switch (sa->sa_family) {
 123         case AF_INET:
 124         case AF_INET6:
 125                 return getnameinfo_inet(sa, salen, host, hostlen,
 126                     serv, servlen, flags);
 127         case AF_LINK:
 128                 return getnameinfo_link(sa, salen, host, hostlen,
 129                     serv, servlen, flags);
 130         default:
 131                 return EAI_FAMILY;
 132         }
 133 }
 134
 135
 136 /*
 137  * getnameinfo_inet():
 138  * Format an IPv4 or IPv6 sockaddr into a printable string.
 139  */
 140 static int
 141 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 142         const struct sockaddr *sa;
 143         socklen_t salen;
 144         char *host;
 145         socklen_t hostlen;
 146         char *serv;
 147         socklen_t servlen;
 148         int flags;
 149 {
 150         const struct afd *afd;
 151         struct servent *sp;
 152         struct hostent *hp;
 153         u_short port;
 154         int family, i;
 155         const char *addr;
 156         u_int32_t v4a;
 157         char numserv[512];
 158         char numaddr[512];
 159
 160         /* sa is checked below */
 161         /* host may be NULL */
 162         /* serv may be NULL */
 163
 164         if (sa == NULL)
 165                 return EAI_FAIL;
 166
 167 #ifdef BSD4_4
 168         if (sa->sa_len != salen)
 169                 return EAI_FAIL;
 170 #endif
 171
 172         family = sa->sa_family;
 173         for (i = 0; afdl[i].a_af; i++)
 174                 if (afdl[i].a_af == family) {
 175                         afd = &afdl[i];
 176                         goto found;
 177                 }
 178         return EAI_FAMILY;
 179
 180  found:
 181         if (salen != afd->a_socklen)
 182                 return EAI_FAIL;
 183
 184         /* network byte order */
 185         port = ((const struct sockinet *)(const void *)sa)->si_port;
 186         addr = (const char *)(const void *)sa + afd->a_off;
 187
 188         if (serv == NULL || servlen == 0) {
 189                 /*
 190                  * do nothing in this case.
 191                  * in case you are wondering if "&&" is more correct than
 192                  * "||" here: rfc2553bis-03 says that serv == NULL OR
 193                  * servlen == 0 means that the caller does not want the result.
 194                  */
 195         } else {
 196                 struct servent_data svd;
 197                 struct servent sv;
 198
 199                 if (flags & NI_NUMERICSERV)
 200                         sp = NULL;
 201                 else {
 202                         (void)memset(&svd, 0, sizeof(svd));
 203                         sp = getservbyport_r(port,
 204                                 (flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
 205                 }
 206                 if (sp) {
 207                         if (strlen(sp->s_name) + 1 > servlen) {
 208                                 endservent_r(&svd);
 209                                 return EAI_MEMORY;
 210                         }
 211                         strlcpy(serv, sp->s_name, servlen);
 212                         endservent_r(&svd);
 213                 } else {
 214                         snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
 215                         if (strlen(numserv) + 1 > servlen)
 216                                 return EAI_MEMORY;
 217                         strlcpy(serv, numserv, servlen);
 218                 }
 219         }
 220
 221         switch (sa->sa_family) {
 222         case AF_INET:
 223                 v4a = (u_int32_t)
 224                     ntohl(((const struct sockaddr_in *)
 225                     (const void *)sa)->sin_addr.s_addr);
 226                 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 227                         flags |= NI_NUMERICHOST;
 228                 v4a >>= IN_CLASSA_NSHIFT;
 229                 if (v4a == 0)
 230                         flags |= NI_NUMERICHOST;
 231                 break;
 232 #ifdef INET6
 233         case AF_INET6:
 234             {
 235                 const struct sockaddr_in6 *sin6;
 236                 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
 237                 switch (sin6->sin6_addr.s6_addr[0]) {
 238                 case 0x00:
 239                         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 240                                 ;
 241                         else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 242                                 ;
 243                         else
 244                                 flags |= NI_NUMERICHOST;
 245                         break;
 246                 default:
 247                         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 248                                 flags |= NI_NUMERICHOST;
 249                         }
 250                         else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 251                                 flags |= NI_NUMERICHOST;
 252                         break;
 253                 }
 254             }
 255                 break;
 256 #endif
 257         }
 258         if (host == NULL || hostlen == 0) {
 259                 /*
 260                  * do nothing in this case.
 261                  * in case you are wondering if "&&" is more correct than
 262                  * "||" here: rfc2553bis-03 says that host == NULL or
 263                  * hostlen == 0 means that the caller does not want the result.
 264                  */
 265         } else if (flags & NI_NUMERICHOST) {
 266                 size_t numaddrlen;
 267
 268                 /* NUMERICHOST and NAMEREQD conflicts with each other */
 269                 if (flags & NI_NAMEREQD)
 270                         return EAI_NONAME;
 271
 272                 switch(afd->a_af) {
 273 #ifdef INET6
 274                 case AF_INET6:
 275                 {
 276                         int error;
 277
 278                         if ((error = ip6_parsenumeric(sa, addr, host,
 279                                                       hostlen, flags)) != 0)
 280                                 return(error);
 281                         break;
 282                 }
 283 #endif
 284                 default:
 285                         if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
 286                             == NULL)
 287                                 return EAI_SYSTEM;
 288                         numaddrlen = strlen(numaddr);
 289                         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 290                                 return EAI_MEMORY;
 291                         strlcpy(host, numaddr, hostlen);
 292                         break;
 293                 }
 294         } else {
 295                 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
 296
 297                 if (hp) {
 298 #if 0
 299                         /*
 300                          * commented out, since "for local host" is not
 301                          * implemented here - see RFC2553 p30
 302                          */
 303                         if (flags & NI_NOFQDN) {
 304                                 char *p;
 305                                 p = strchr(hp->h_name, '.');
 306                                 if (p)
 307                                         *p = '\0';
 308                         }
 309 #endif
 310                         if (strlen(hp->h_name) + 1 > hostlen) {
 311                                 return EAI_MEMORY;
 312                         }
 313                         strlcpy(host, hp->h_name, hostlen);
 314                 } else {
 315                         if (flags & NI_NAMEREQD)
 316                                 return EAI_NONAME;
 317                         switch(afd->a_af) {
 318 #ifdef INET6
 319                         case AF_INET6:
 320                         {
 321                                 int error;
 322
 323                                 if ((error = ip6_parsenumeric(sa, addr, host,
 324                                                               hostlen,
 325                                                               flags)) != 0)
 326                                         return(error);
 327                                 break;
 328                         }
 329 #endif
 330                         default:
 331                                 if (inet_ntop(afd->a_af, addr, host,
 332                                     hostlen) == NULL)
 333                                         return EAI_SYSTEM;
 334                                 break;
 335                         }
 336                 }
 337         }
 338         return(0);
 339 }
 340
 341 #ifdef INET6
 342 static int
 343 ip6_parsenumeric(sa, addr, host, hostlen, flags)
 344         const struct sockaddr *sa;
 345         const char *addr;
 346         char *host;
 347         socklen_t hostlen;
 348         int flags;
 349 {
 350         size_t numaddrlen;
 351         char numaddr[512];
 352
 353         _DIAGASSERT(sa != NULL);
 354         _DIAGASSERT(addr != NULL);
 355         _DIAGASSERT(host != NULL);
 356
 357         if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
 358                 return EAI_SYSTEM;
 359
 360         numaddrlen = strlen(numaddr);
 361         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 362                 return EAI_OVERFLOW;
 363         strlcpy(host, numaddr, hostlen);
 364
 365         if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
 366                 char zonebuf[MAXHOSTNAMELEN];
 367                 int zonelen;
 368
 369                 zonelen = ip6_sa2str(
 370                     (const struct sockaddr_in6 *)(const void *)sa,
 371                     zonebuf, sizeof(zonebuf), flags);
 372                 if (zonelen < 0)
 373                         return EAI_OVERFLOW;
 374                 if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
 375                         return EAI_OVERFLOW;
 376                 /* construct <numeric-addr><delim><zoneid> */
 377                 memcpy(host + numaddrlen + 1, zonebuf,
 378                     (size_t)zonelen);
 379                 host[numaddrlen] = SCOPE_DELIMITER;
 380                 host[numaddrlen + 1 + zonelen] = '\0';
 381         }
 382
 383         return 0;
 384 }
 385
 386 /* ARGSUSED */
 387 static int
 388 ip6_sa2str(sa6, buf, bufsiz, flags)
 389         const struct sockaddr_in6 *sa6;
 390         char *buf;
 391         size_t bufsiz;
 392         int flags;
 393 {
 394         unsigned int ifindex;
 395         const struct in6_addr *a6;
 396         int n;
 397
 398         _DIAGASSERT(sa6 != NULL);
 399         _DIAGASSERT(buf != NULL);
 400
 401         ifindex = (unsigned int)sa6->sin6_scope_id;
 402         a6 = &sa6->sin6_addr;
 403
 404 #ifdef NI_NUMERICSCOPE
 405         if ((flags & NI_NUMERICSCOPE) != 0) {
 406                 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 407                 if (n < 0 || (size_t)n >= bufsiz)
 408                         return -1;
 409                 else
 410                         return n;
 411         }
 412 #endif
 413
 414         /* if_indextoname() does not take buffer size.  not a good api... */
 415         if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
 416             bufsiz >= IF_NAMESIZE) {
 417                 char *p = if_indextoname(ifindex, buf);
 418                 if (p) {
 419                         return(strlen(p));
 420                 }
 421         }
 422
 423         /* last resort */
 424         n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 425         if (n < 0 || (size_t) n >= bufsiz)
 426                 return -1;
 427         else
 428                 return n;
 429 }
 430 #endif /* INET6 */
 431
 432
 433 /*
 434  * getnameinfo_link():
 435  * Format a link-layer address into a printable format, paying attention to
 436  * the interface type.
 437  */
 438 /* ARGSUSED */
 439 static int
 440 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
 441     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 442     int flags)
 443 {
 444         const struct sockaddr_dl *sdl =
 445             (const struct sockaddr_dl *)(const void *)sa;
 446         const struct ieee1394_hwaddr *iha;
 447         int n;
 448
 449         if (serv != NULL && servlen > 0)
 450                 *serv = '\0';
 451
 452         if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
 453                 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
 454                 if (n < 0 || (socklen_t) n > hostlen) {
 455                         *host = '\0';
 456                         return EAI_MEMORY;
 457                 }
 458                 return 0;
 459         }
 460
 461         switch (sdl->sdl_type) {
 462 #ifdef IFT_ECONET
 463         case IFT_ECONET:
 464                 if (sdl->sdl_alen < 2)
 465                         return EAI_FAMILY;
 466                 if (CLLADDR(sdl)[1] == 0)
 467                         n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
 468                 else
 469                         n = snprintf(host, hostlen, "%u.%u",
 470                             CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
 471                 if (n < 0 || (socklen_t) n >= hostlen) {
 472                         *host = '\0';
 473                         return EAI_MEMORY;
 474                 } else
 475                         return 0;
 476 #endif
 477         case IFT_IEEE1394:
 478                 if (sdl->sdl_alen < sizeof(iha->iha_uid))
 479                         return EAI_FAMILY;
 480                 iha =
 481                     (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
 482                 return hexname(iha->iha_uid, sizeof(iha->iha_uid),
 483                     host, hostlen);
 484         /*
 485          * The following have zero-length addresses.
 486          * IFT_ATM      (net/if_atmsubr.c)
 487          * IFT_FAITH    (net/if_faith.c)
 488          * IFT_GIF      (net/if_gif.c)
 489          * IFT_LOOP     (net/if_loop.c)
 490          * IFT_PPP      (net/if_ppp.c, net/if_spppsubr.c)
 491          * IFT_SLIP     (net/if_sl.c, net/if_strip.c)
 492          * IFT_STF      (net/if_stf.c)
 493          * IFT_L2VLAN   (net/if_vlan.c)
 494          * IFT_PROPVIRTUAL (net/if_bridge.h>
 495          */
 496         /*
 497          * The following use IPv4 addresses as link-layer addresses:
 498          * IFT_OTHER    (net/if_gre.c)
 499          */
 500         case IFT_ARCNET: /* default below is believed correct for all these. */
 501         case IFT_ETHER:
 502         case IFT_FDDI:
 503         case IFT_HIPPI:
 504         case IFT_ISO88025:
 505         default:
 506                 return hexname((const u_int8_t *)CLLADDR(sdl),
 507                     (size_t)sdl->sdl_alen, host, hostlen);
 508         }
 509 }
 510
 511 static int
 512 hexname(cp, len, host, hostlen)
 513         const u_int8_t *cp;
 514         char *host;
 515         size_t len;
 516         socklen_t hostlen;
 517 {
 518         int n;
 519         size_t i;
 520         char *outp = host;
 521
 522         *outp = '\0';
 523         for (i = 0; i < len; i++) {
 524                 n = snprintf(outp, hostlen, "%s%02x",
 525                     i ? ":" : "", cp[i]);
 526                 if (n < 0 || (socklen_t) n >= hostlen) {
 527                         *host = '\0';
 528                         return EAI_MEMORY;
 529                 }
 530                 outp += n;
 531                 hostlen -= n;
 532         }
 533         return 0;
 534 }