lib/libc/net/getnameinfo.c

   1 /*      $NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos 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 1.53 2012/09/26 23:13:00 christos 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 <sys/un.h>
  57 #include <net/if.h>
  58 #ifndef __minix
  59 #include <net/if_dl.h>
  60 #include <net/if_ieee1394.h>
  61 #include <net/if_types.h>
  62 #include <netatalk/at.h>
  63 #endif /* !__minix */
  64 #include <netinet/in.h>
  65 #include <arpa/inet.h>
  66 #include <arpa/nameser.h>
  67 #include <assert.h>
  68 #include <limits.h>
  69 #include <netdb.h>
  70 #include <resolv.h>
  71 #include <stddef.h>
  72 #include <string.h>
  73
  74 #include "servent.h"
  75
  76 #ifdef __weak_alias
  77 __weak_alias(getnameinfo,_getnameinfo)
  78 #endif
  79
  80 static const struct afd {
  81         int             a_af;
  82         socklen_t       a_addrlen;
  83         socklen_t       a_socklen;
  84         int             a_off;
  85 } afdl [] = {
  86 #ifdef INET6
  87         {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
  88                 offsetof(struct sockaddr_in6, sin6_addr)},
  89 #endif
  90         {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
  91                 offsetof(struct sockaddr_in, sin_addr)},
  92         {0, 0, 0, 0},
  93 };
  94
  95 struct sockinet {
  96         u_char  si_len;
  97         u_char  si_family;
  98         u_short si_port;
  99 };
 100
 101 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
 102     socklen_t, char *, socklen_t, int);
 103 #ifdef INET6
 104 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
 105                                  socklen_t, int);
 106 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
 107 #endif
 108 #ifndef __minix
 109 static int getnameinfo_atalk(const struct sockaddr *, socklen_t, char *,
 110     socklen_t, char *, socklen_t, int);
 111 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
 112     socklen_t, char *, socklen_t, int);
 113
 114 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
 115     socklen_t, char *, socklen_t, int);
 116 static int hexname(const uint8_t *, size_t, char *, socklen_t);
 117 #endif /* __minix */
 118
 119 /*
 120  * Top-level getnameinfo() code.  Look at the address family, and pick an
 121  * appropriate function to call.
 122  */
 123 int
 124 getnameinfo(const struct sockaddr *sa, socklen_t salen,
 125         char *host, socklen_t hostlen,
 126         char *serv, socklen_t servlen,
 127         int flags)
 128 {
 129
 130         switch (sa->sa_family) {
 131 #ifndef __minix
 132         case AF_APPLETALK:
 133                 return getnameinfo_atalk(sa, salen, host, hostlen,
 134                     serv, servlen, flags);
 135 #endif /* !__minix */
 136         case AF_INET:
 137         case AF_INET6:
 138                 return getnameinfo_inet(sa, salen, host, hostlen,
 139                     serv, servlen, flags);
 140 #ifndef __minix
 141         case AF_LINK:
 142                 return getnameinfo_link(sa, salen, host, hostlen,
 143                     serv, servlen, flags);
 144         case AF_LOCAL:
 145                 return getnameinfo_local(sa, salen, host, hostlen,
 146                     serv, servlen, flags);
 147 #endif /* !__minix */
 148         default:
 149                 return EAI_FAMILY;
 150         }
 151 }
 152
 153 #ifndef __minix
 154 /*
 155  * getnameinfo_atalk():
 156  * Format an AppleTalk address into a printable format.
 157  */
 158 /* ARGSUSED */
 159 static int
 160 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
 161     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 162     int flags)
 163 {
 164         char numserv[8];
 165         int n, m=0;
 166
 167         const struct sockaddr_at *sat =
 168             (const struct sockaddr_at *)(const void *)sa;
 169
 170         if (serv != NULL && servlen > 0) {
 171                 snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
 172                 if (strlen(numserv) + 1 > servlen)
 173                         return EAI_MEMORY;
 174                 strlcpy(serv, numserv, servlen);
 175         }
 176
 177         n = snprintf(host, hostlen, "%u.%u",
 178             ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
 179
 180         if (n < 0 || (socklen_t)(m+n) >= hostlen)
 181                 goto errout;
 182
 183         m += n;
 184
 185         if (sat->sat_range.r_netrange.nr_phase) {
 186                 n = snprintf(host+m, hostlen-m, " phase %u",
 187                         sat->sat_range.r_netrange.nr_phase);
 188
 189                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 190                         goto errout;
 191
 192                 m += n;
 193         }
 194         if (sat->sat_range.r_netrange.nr_firstnet) {
 195                 n = snprintf(host+m, hostlen-m, " range %u - %u",
 196                         ntohs(sat->sat_range.r_netrange.nr_firstnet),
 197                         ntohs(sat->sat_range.r_netrange.nr_lastnet ));
 198
 199                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 200                         goto errout;
 201
 202                 m += n;
 203         }
 204
 205         return 0;
 206
 207 errout:
 208         if (host && hostlen>0)
 209                 host[m] = '\0'; /* XXX ??? */
 210
 211         return EAI_MEMORY;
 212 }
 213
 214 /*
 215  * getnameinfo_local():
 216  * Format an local address into a printable format.
 217  */
 218 /* ARGSUSED */
 219 static int
 220 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
 221     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 222     int flags)
 223 {
 224         const struct sockaddr_un *sun =
 225             (const struct sockaddr_un *)(const void *)sa;
 226
 227         if (serv != NULL && servlen > 0)
 228                 serv[0] = '\0';
 229
 230         if (host && hostlen > 0)
 231                 strlcpy(host, sun->sun_path,
 232                     MIN(sizeof(sun->sun_path) + 1, hostlen));
 233
 234         return 0;
 235 }
 236 #endif /* !__minix */
 237
 238 /*
 239  * getnameinfo_inet():
 240  * Format an IPv4 or IPv6 sockaddr into a printable string.
 241  */
 242 static int
 243 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
 244         char *host, socklen_t hostlen,
 245         char *serv, socklen_t servlen,
 246         int flags)
 247 {
 248         const struct afd *afd;
 249         struct servent *sp;
 250         struct hostent *hp;
 251         u_short port;
 252         int family, i;
 253         const char *addr;
 254         uint32_t v4a;
 255         char numserv[512];
 256         char numaddr[512];
 257
 258         /* sa is checked below */
 259         /* host may be NULL */
 260         /* serv may be NULL */
 261
 262         if (sa == NULL)
 263                 return EAI_FAIL;
 264
 265         family = sa->sa_family;
 266         for (i = 0; afdl[i].a_af; i++)
 267                 if (afdl[i].a_af == family) {
 268                         afd = &afdl[i];
 269                         goto found;
 270                 }
 271         return EAI_FAMILY;
 272
 273  found:
 274         if (salen != afd->a_socklen)
 275                 return EAI_FAIL;
 276
 277         /* network byte order */
 278         port = ((const struct sockinet *)(const void *)sa)->si_port;
 279         addr = (const char *)(const void *)sa + afd->a_off;
 280
 281         if (serv == NULL || servlen == 0) {
 282                 /*
 283                  * do nothing in this case.
 284                  * in case you are wondering if "&&" is more correct than
 285                  * "||" here: rfc2553bis-03 says that serv == NULL OR
 286                  * servlen == 0 means that the caller does not want the result.
 287                  */
 288         } else {
 289                 struct servent_data svd;
 290                 struct servent sv;
 291
 292                 if (flags & NI_NUMERICSERV)
 293                         sp = NULL;
 294                 else {
 295                         (void)memset(&svd, 0, sizeof(svd));
 296                         sp = getservbyport_r(port,
 297                                 (flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
 298                 }
 299                 if (sp) {
 300                         if (strlen(sp->s_name) + 1 > servlen) {
 301                                 endservent_r(&svd);
 302                                 return EAI_MEMORY;
 303                         }
 304                         strlcpy(serv, sp->s_name, servlen);
 305                         endservent_r(&svd);
 306                 } else {
 307                         snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
 308                         if (strlen(numserv) + 1 > servlen)
 309                                 return EAI_MEMORY;
 310                         strlcpy(serv, numserv, servlen);
 311                 }
 312         }
 313
 314         switch (sa->sa_family) {
 315         case AF_INET:
 316                 v4a = (uint32_t)
 317                     ntohl(((const struct sockaddr_in *)
 318                     (const void *)sa)->sin_addr.s_addr);
 319                 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 320                         flags |= NI_NUMERICHOST;
 321                 v4a >>= IN_CLASSA_NSHIFT;
 322                 if (v4a == 0)
 323                         flags |= NI_NUMERICHOST;
 324                 break;
 325 #ifdef INET6
 326         case AF_INET6:
 327             {
 328                 const struct sockaddr_in6 *sin6;
 329                 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
 330                 switch (sin6->sin6_addr.s6_addr[0]) {
 331                 case 0x00:
 332                         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 333                                 ;
 334                         else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 335                                 ;
 336                         else
 337                                 flags |= NI_NUMERICHOST;
 338                         break;
 339                 default:
 340                         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 341                                 flags |= NI_NUMERICHOST;
 342                         }
 343                         else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 344                                 flags |= NI_NUMERICHOST;
 345                         break;
 346                 }
 347             }
 348                 break;
 349 #endif
 350         }
 351         if (host == NULL || hostlen == 0) {
 352                 /*
 353                  * do nothing in this case.
 354                  * in case you are wondering if "&&" is more correct than
 355                  * "||" here: rfc2553bis-03 says that host == NULL or
 356                  * hostlen == 0 means that the caller does not want the result.
 357                  */
 358         } else if (flags & NI_NUMERICHOST) {
 359                 size_t numaddrlen;
 360
 361                 /* NUMERICHOST and NAMEREQD conflicts with each other */
 362                 if (flags & NI_NAMEREQD)
 363                         return EAI_NONAME;
 364
 365                 switch(afd->a_af) {
 366 #ifdef INET6
 367                 case AF_INET6:
 368                 {
 369                         int error;
 370
 371                         if ((error = ip6_parsenumeric(sa, addr, host,
 372                                                       hostlen, flags)) != 0)
 373                                 return(error);
 374                         break;
 375                 }
 376 #endif
 377                 default:
 378                         if (inet_ntop(afd->a_af, addr, numaddr,
 379                             (socklen_t)sizeof(numaddr)) == NULL)
 380                                 return EAI_SYSTEM;
 381                         numaddrlen = strlen(numaddr);
 382                         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 383                                 return EAI_MEMORY;
 384                         strlcpy(host, numaddr, hostlen);
 385                         break;
 386                 }
 387         } else {
 388                 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
 389
 390                 if (hp) {
 391 #if 0
 392                         /*
 393                          * commented out, since "for local host" is not
 394                          * implemented here - see RFC2553 p30
 395                          */
 396                         if (flags & NI_NOFQDN) {
 397                                 char *p;
 398                                 p = strchr(hp->h_name, '.');
 399                                 if (p)
 400                                         *p = '\0';
 401                         }
 402 #endif
 403                         if (strlen(hp->h_name) + 1 > hostlen) {
 404                                 return EAI_MEMORY;
 405                         }
 406                         strlcpy(host, hp->h_name, hostlen);
 407                 } else {
 408                         if (flags & NI_NAMEREQD)
 409                                 return EAI_NONAME;
 410                         switch(afd->a_af) {
 411 #ifdef INET6
 412                         case AF_INET6:
 413                         {
 414                                 int error;
 415
 416                                 if ((error = ip6_parsenumeric(sa, addr, host,
 417                                                               hostlen,
 418                                                               flags)) != 0)
 419                                         return(error);
 420                                 break;
 421                         }
 422 #endif
 423                         default:
 424                                 if (inet_ntop(afd->a_af, addr, host,
 425                                     hostlen) == NULL)
 426                                         return EAI_SYSTEM;
 427                                 break;
 428                         }
 429                 }
 430         }
 431         return(0);
 432 }
 433
 434 #ifdef INET6
 435 static int
 436 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
 437         socklen_t hostlen, int flags)
 438 {
 439         size_t numaddrlen;
 440         char numaddr[512];
 441
 442         _DIAGASSERT(sa != NULL);
 443         _DIAGASSERT(addr != NULL);
 444         _DIAGASSERT(host != NULL);
 445
 446         if (inet_ntop(AF_INET6, addr, numaddr, (socklen_t)sizeof(numaddr))
 447             == NULL)
 448                 return EAI_SYSTEM;
 449
 450         numaddrlen = strlen(numaddr);
 451         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 452                 return EAI_OVERFLOW;
 453         strlcpy(host, numaddr, hostlen);
 454
 455         if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
 456                 char zonebuf[MAXHOSTNAMELEN];
 457                 int zonelen;
 458
 459                 zonelen = ip6_sa2str(
 460                     (const struct sockaddr_in6 *)(const void *)sa,
 461                     zonebuf, sizeof(zonebuf), flags);
 462                 if (zonelen < 0)
 463                         return EAI_OVERFLOW;
 464                 if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
 465                         return EAI_OVERFLOW;
 466                 /* construct <numeric-addr><delim><zoneid> */
 467                 memcpy(host + numaddrlen + 1, zonebuf,
 468                     (size_t)zonelen);
 469                 host[numaddrlen] = SCOPE_DELIMITER;
 470                 host[numaddrlen + 1 + zonelen] = '\0';
 471         }
 472
 473         return 0;
 474 }
 475
 476 /* ARGSUSED */
 477 static int
 478 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
 479 {
 480         unsigned int ifindex;
 481         const struct in6_addr *a6;
 482         int n;
 483
 484         _DIAGASSERT(sa6 != NULL);
 485         _DIAGASSERT(buf != NULL);
 486
 487         ifindex = (unsigned int)sa6->sin6_scope_id;
 488         a6 = &sa6->sin6_addr;
 489
 490 #ifdef NI_NUMERICSCOPE
 491         if ((flags & NI_NUMERICSCOPE) != 0) {
 492                 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 493                 if (n < 0 || (size_t)n >= bufsiz)
 494                         return -1;
 495                 else
 496                         return n;
 497         }
 498 #endif
 499
 500         /* if_indextoname() does not take buffer size.  not a good api... */
 501         if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
 502             bufsiz >= IF_NAMESIZE) {
 503                 char *p = if_indextoname(ifindex, buf);
 504                 if (p) {
 505                         return (int)strlen(p);
 506                 }
 507         }
 508
 509         /* last resort */
 510         n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 511         if (n < 0 || (size_t) n >= bufsiz)
 512                 return -1;
 513         else
 514                 return n;
 515 }
 516 #endif /* INET6 */
 517
 518
 519 #ifndef __minix
 520 /*
 521  * getnameinfo_link():
 522  * Format a link-layer address into a printable format, paying attention to
 523  * the interface type.
 524  */
 525 /* ARGSUSED */
 526 static int
 527 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
 528     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 529     int flags)
 530 {
 531         const struct sockaddr_dl *sdl =
 532             (const struct sockaddr_dl *)(const void *)sa;
 533         const struct ieee1394_hwaddr *iha;
 534         int n;
 535
 536         if (serv != NULL && servlen > 0)
 537                 *serv = '\0';
 538
 539         if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
 540                 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
 541                 if (n < 0 || (socklen_t) n > hostlen) {
 542                         *host = '\0';
 543                         return EAI_MEMORY;
 544                 }
 545                 return 0;
 546         }
 547
 548         switch (sdl->sdl_type) {
 549 #ifdef IFT_ECONET
 550         case IFT_ECONET:
 551                 if (sdl->sdl_alen < 2)
 552                         return EAI_FAMILY;
 553                 if (CLLADDR(sdl)[1] == 0)
 554                         n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
 555                 else
 556                         n = snprintf(host, hostlen, "%u.%u",
 557                             CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
 558                 if (n < 0 || (socklen_t) n >= hostlen) {
 559                         *host = '\0';
 560                         return EAI_MEMORY;
 561                 } else
 562                         return 0;
 563 #endif
 564         case IFT_IEEE1394:
 565                 if (sdl->sdl_alen < sizeof(iha->iha_uid))
 566                         return EAI_FAMILY;
 567                 iha =
 568                     (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
 569                 return hexname(iha->iha_uid, sizeof(iha->iha_uid),
 570                     host, hostlen);
 571         /*
 572          * The following have zero-length addresses.
 573          * IFT_ATM      (net/if_atmsubr.c)
 574          * IFT_FAITH    (net/if_faith.c)
 575          * IFT_GIF      (net/if_gif.c)
 576          * IFT_LOOP     (net/if_loop.c)
 577          * IFT_PPP      (net/if_ppp.c, net/if_spppsubr.c)
 578          * IFT_SLIP     (net/if_sl.c, net/if_strip.c)
 579          * IFT_STF      (net/if_stf.c)
 580          * IFT_L2VLAN   (net/if_vlan.c)
 581          * IFT_PROPVIRTUAL (net/if_bridge.h>
 582          */
 583         /*
 584          * The following use IPv4 addresses as link-layer addresses:
 585          * IFT_OTHER    (net/if_gre.c)
 586          */
 587         case IFT_ARCNET: /* default below is believed correct for all these. */
 588         case IFT_ETHER:
 589         case IFT_FDDI:
 590         case IFT_HIPPI:
 591         case IFT_ISO88025:
 592         default:
 593                 return hexname((const uint8_t *)CLLADDR(sdl),
 594                     (size_t)sdl->sdl_alen, host, hostlen);
 595         }
 596 }
 597
 598 static int
 599 hexname(const uint8_t *cp, size_t len, char *host, socklen_t hostlen)
 600 {
 601         int n;
 602         size_t i;
 603         char *outp = host;
 604
 605         *outp = '\0';
 606         for (i = 0; i < len; i++) {
 607                 n = snprintf(outp, hostlen, "%s%02x",
 608                     i ? ":" : "", cp[i]);
 609                 if (n < 0 || (socklen_t) n >= hostlen) {
 610                         *host = '\0';
 611                         return EAI_MEMORY;
 612                 }
 613                 outp += n;
 614                 hostlen -= n;
 615         }
 616         return 0;
 617 }
 618 #endif /* !__minix */