lib/libc/net/getnameinfo.c

   1 /*      $NetBSD: getnameinfo.c,v 1.54 2013/08/16 15:27:12 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 1.54 2013/08/16 15:27:12 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 #if !defined(__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 /* !defined(__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 #include "hostent.h"
  76
  77 #ifdef __weak_alias
  78 __weak_alias(getnameinfo,_getnameinfo)
  79 #endif
  80
  81 static const struct afd {
  82         int             a_af;
  83         socklen_t       a_addrlen;
  84         socklen_t       a_socklen;
  85         int             a_off;
  86 } afdl [] = {
  87 #ifdef INET6
  88         {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
  89                 offsetof(struct sockaddr_in6, sin6_addr)},
  90 #endif
  91         {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
  92                 offsetof(struct sockaddr_in, sin_addr)},
  93         {0, 0, 0, 0},
  94 };
  95
  96 struct sockinet {
  97         u_char  si_len;
  98         u_char  si_family;
  99         u_short si_port;
 100 };
 101
 102 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
 103     socklen_t, char *, socklen_t, int);
 104 #ifdef INET6
 105 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
 106                                  socklen_t, int);
 107 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
 108 #endif
 109 #if !defined(__minix)
 110 static int getnameinfo_atalk(const struct sockaddr *, socklen_t, char *,
 111     socklen_t, char *, socklen_t, int);
 112 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
 113     socklen_t, char *, socklen_t, int);
 114
 115 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
 116     socklen_t, char *, socklen_t, int);
 117 static int hexname(const uint8_t *, size_t, char *, socklen_t);
 118 #endif /* !defined(__minix) */
 119
 120 /*
 121  * Top-level getnameinfo() code.  Look at the address family, and pick an
 122  * appropriate function to call.
 123  */
 124 int
 125 getnameinfo(const struct sockaddr *sa, socklen_t salen,
 126         char *host, socklen_t hostlen,
 127         char *serv, socklen_t servlen,
 128         int flags)
 129 {
 130
 131         switch (sa->sa_family) {
 132 #if !defined(__minix)
 133         case AF_APPLETALK:
 134                 return getnameinfo_atalk(sa, salen, host, hostlen,
 135                     serv, servlen, flags);
 136 #endif /* !defined(__minix) */
 137         case AF_INET:
 138         case AF_INET6:
 139                 return getnameinfo_inet(sa, salen, host, hostlen,
 140                     serv, servlen, flags);
 141 #if !defined(__minix)
 142         case AF_LINK:
 143                 return getnameinfo_link(sa, salen, host, hostlen,
 144                     serv, servlen, flags);
 145         case AF_LOCAL:
 146                 return getnameinfo_local(sa, salen, host, hostlen,
 147                     serv, servlen, flags);
 148 #endif /* !defined(__minix) */
 149         default:
 150                 return EAI_FAMILY;
 151         }
 152 }
 153
 154 #if !defined(__minix)
 155 /*
 156  * getnameinfo_atalk():
 157  * Format an AppleTalk address into a printable format.
 158  */
 159 /* ARGSUSED */
 160 static int
 161 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
 162     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 163     int flags)
 164 {
 165         char numserv[8];
 166         int n, m=0;
 167
 168         const struct sockaddr_at *sat =
 169             (const struct sockaddr_at *)(const void *)sa;
 170
 171         if (serv != NULL && servlen > 0) {
 172                 snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
 173                 if (strlen(numserv) + 1 > servlen)
 174                         return EAI_MEMORY;
 175                 strlcpy(serv, numserv, servlen);
 176         }
 177
 178         n = snprintf(host, hostlen, "%u.%u",
 179             ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
 180
 181         if (n < 0 || (socklen_t)(m+n) >= hostlen)
 182                 goto errout;
 183
 184         m += n;
 185
 186         if (sat->sat_range.r_netrange.nr_phase) {
 187                 n = snprintf(host+m, hostlen-m, " phase %u",
 188                         sat->sat_range.r_netrange.nr_phase);
 189
 190                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 191                         goto errout;
 192
 193                 m += n;
 194         }
 195         if (sat->sat_range.r_netrange.nr_firstnet) {
 196                 n = snprintf(host+m, hostlen-m, " range %u - %u",
 197                         ntohs(sat->sat_range.r_netrange.nr_firstnet),
 198                         ntohs(sat->sat_range.r_netrange.nr_lastnet ));
 199
 200                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 201                         goto errout;
 202
 203                 m += n;
 204         }
 205
 206         return 0;
 207
 208 errout:
 209         if (host && hostlen>0)
 210                 host[m] = '\0'; /* XXX ??? */
 211
 212         return EAI_MEMORY;
 213 }
 214
 215 /*
 216  * getnameinfo_local():
 217  * Format an local address into a printable format.
 218  */
 219 /* ARGSUSED */
 220 static int
 221 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
 222     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 223     int flags)
 224 {
 225         const struct sockaddr_un *sun =
 226             (const struct sockaddr_un *)(const void *)sa;
 227
 228         if (serv != NULL && servlen > 0)
 229                 serv[0] = '\0';
 230
 231         if (host && hostlen > 0)
 232                 strlcpy(host, sun->sun_path,
 233                     MIN(sizeof(sun->sun_path) + 1, hostlen));
 234
 235         return 0;
 236 }
 237 #endif /* !defined(__minix) */
 238
 239 /*
 240  * getnameinfo_inet():
 241  * Format an IPv4 or IPv6 sockaddr into a printable string.
 242  */
 243 static int
 244 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
 245         char *host, socklen_t hostlen,
 246         char *serv, socklen_t servlen,
 247         int flags)
 248 {
 249         const struct afd *afd;
 250         struct servent *sp;
 251         struct hostent *hp;
 252         u_short port;
 253         int family, i;
 254         const char *addr;
 255         uint32_t v4a;
 256         char numserv[512];
 257         char numaddr[512];
 258
 259         /* sa is checked below */
 260         /* host may be NULL */
 261         /* serv may be NULL */
 262
 263         if (sa == NULL)
 264                 return EAI_FAIL;
 265
 266         family = sa->sa_family;
 267         for (i = 0; afdl[i].a_af; i++)
 268                 if (afdl[i].a_af == family) {
 269                         afd = &afdl[i];
 270                         goto found;
 271                 }
 272         return EAI_FAMILY;
 273
 274  found:
 275         if (salen != afd->a_socklen)
 276                 return EAI_FAIL;
 277
 278         /* network byte order */
 279         port = ((const struct sockinet *)(const void *)sa)->si_port;
 280         addr = (const char *)(const void *)sa + afd->a_off;
 281
 282         if (serv == NULL || servlen == 0) {
 283                 /*
 284                  * do nothing in this case.
 285                  * in case you are wondering if "&&" is more correct than
 286                  * "||" here: rfc2553bis-03 says that serv == NULL OR
 287                  * servlen == 0 means that the caller does not want the result.
 288                  */
 289         } else {
 290                 struct servent_data svd;
 291                 struct servent sv;
 292
 293                 if (flags & NI_NUMERICSERV)
 294                         sp = NULL;
 295                 else {
 296                         (void)memset(&svd, 0, sizeof(svd));
 297                         sp = getservbyport_r(port,
 298                                 (flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
 299                 }
 300                 if (sp) {
 301                         if (strlen(sp->s_name) + 1 > servlen) {
 302                                 endservent_r(&svd);
 303                                 return EAI_MEMORY;
 304                         }
 305                         strlcpy(serv, sp->s_name, servlen);
 306                         endservent_r(&svd);
 307                 } else {
 308                         snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
 309                         if (strlen(numserv) + 1 > servlen)
 310                                 return EAI_MEMORY;
 311                         strlcpy(serv, numserv, servlen);
 312                 }
 313         }
 314
 315         switch (sa->sa_family) {
 316         case AF_INET:
 317                 v4a = (uint32_t)
 318                     ntohl(((const struct sockaddr_in *)
 319                     (const void *)sa)->sin_addr.s_addr);
 320                 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 321                         flags |= NI_NUMERICHOST;
 322                 v4a >>= IN_CLASSA_NSHIFT;
 323                 if (v4a == 0)
 324                         flags |= NI_NUMERICHOST;
 325                 break;
 326 #ifdef INET6
 327         case AF_INET6:
 328             {
 329                 const struct sockaddr_in6 *sin6;
 330                 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
 331                 switch (sin6->sin6_addr.s6_addr[0]) {
 332                 case 0x00:
 333                         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 334                                 ;
 335                         else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 336                                 ;
 337                         else
 338                                 flags |= NI_NUMERICHOST;
 339                         break;
 340                 default:
 341                         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 342                                 flags |= NI_NUMERICHOST;
 343                         }
 344                         else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 345                                 flags |= NI_NUMERICHOST;
 346                         break;
 347                 }
 348             }
 349                 break;
 350 #endif
 351         }
 352         if (host == NULL || hostlen == 0) {
 353                 /*
 354                  * do nothing in this case.
 355                  * in case you are wondering if "&&" is more correct than
 356                  * "||" here: rfc2553bis-03 says that host == NULL or
 357                  * hostlen == 0 means that the caller does not want the result.
 358                  */
 359         } else if (flags & NI_NUMERICHOST) {
 360                 size_t numaddrlen;
 361
 362                 /* NUMERICHOST and NAMEREQD conflicts with each other */
 363                 if (flags & NI_NAMEREQD)
 364                         return EAI_NONAME;
 365
 366                 switch(afd->a_af) {
 367 #ifdef INET6
 368                 case AF_INET6:
 369                 {
 370                         int error;
 371
 372                         if ((error = ip6_parsenumeric(sa, addr, host,
 373                                                       hostlen, flags)) != 0)
 374                                 return(error);
 375                         break;
 376                 }
 377 #endif
 378                 default:
 379                         if (inet_ntop(afd->a_af, addr, numaddr,
 380                             (socklen_t)sizeof(numaddr)) == NULL)
 381                                 return EAI_SYSTEM;
 382                         numaddrlen = strlen(numaddr);
 383                         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 384                                 return EAI_MEMORY;
 385                         strlcpy(host, numaddr, hostlen);
 386                         break;
 387                 }
 388         } else {
 389                 struct hostent hent;
 390                 char hbuf[4096];
 391                 int he;
 392                 hp = gethostbyaddr_r(addr, afd->a_addrlen, afd->a_af, &hent,
 393                     hbuf, sizeof(hbuf), &he);
 394
 395                 if (hp) {
 396 #if 0
 397                         /*
 398                          * commented out, since "for local host" is not
 399                          * implemented here - see RFC2553 p30
 400                          */
 401                         if (flags & NI_NOFQDN) {
 402                                 char *p;
 403                                 p = strchr(hp->h_name, '.');
 404                                 if (p)
 405                                         *p = '\0';
 406                         }
 407 #endif
 408                         if (strlen(hp->h_name) + 1 > hostlen) {
 409                                 return EAI_MEMORY;
 410                         }
 411                         strlcpy(host, hp->h_name, hostlen);
 412                 } else {
 413                         if (flags & NI_NAMEREQD)
 414                                 return EAI_NONAME;
 415                         switch(afd->a_af) {
 416 #ifdef INET6
 417                         case AF_INET6:
 418                         {
 419                                 int error;
 420
 421                                 if ((error = ip6_parsenumeric(sa, addr, host,
 422                                                               hostlen,
 423                                                               flags)) != 0)
 424                                         return(error);
 425                                 break;
 426                         }
 427 #endif
 428                         default:
 429                                 if (inet_ntop(afd->a_af, addr, host,
 430                                     hostlen) == NULL)
 431                                         return EAI_SYSTEM;
 432                                 break;
 433                         }
 434                 }
 435         }
 436         return(0);
 437 }
 438
 439 #ifdef INET6
 440 static int
 441 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
 442         socklen_t hostlen, int flags)
 443 {
 444         size_t numaddrlen;
 445         char numaddr[512];
 446
 447         _DIAGASSERT(sa != NULL);
 448         _DIAGASSERT(addr != NULL);
 449         _DIAGASSERT(host != NULL);
 450
 451         if (inet_ntop(AF_INET6, addr, numaddr, (socklen_t)sizeof(numaddr))
 452             == NULL)
 453                 return EAI_SYSTEM;
 454
 455         numaddrlen = strlen(numaddr);
 456         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 457                 return EAI_OVERFLOW;
 458         strlcpy(host, numaddr, hostlen);
 459
 460         if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
 461                 char zonebuf[MAXHOSTNAMELEN];
 462                 int zonelen;
 463
 464                 zonelen = ip6_sa2str(
 465                     (const struct sockaddr_in6 *)(const void *)sa,
 466                     zonebuf, sizeof(zonebuf), flags);
 467                 if (zonelen < 0)
 468                         return EAI_OVERFLOW;
 469                 if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
 470                         return EAI_OVERFLOW;
 471                 /* construct <numeric-addr><delim><zoneid> */
 472                 memcpy(host + numaddrlen + 1, zonebuf,
 473                     (size_t)zonelen);
 474                 host[numaddrlen] = SCOPE_DELIMITER;
 475                 host[numaddrlen + 1 + zonelen] = '\0';
 476         }
 477
 478         return 0;
 479 }
 480
 481 /* ARGSUSED */
 482 static int
 483 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
 484 {
 485         unsigned int ifindex;
 486         const struct in6_addr *a6;
 487         int n;
 488
 489         _DIAGASSERT(sa6 != NULL);
 490         _DIAGASSERT(buf != NULL);
 491
 492         ifindex = (unsigned int)sa6->sin6_scope_id;
 493         a6 = &sa6->sin6_addr;
 494
 495 #ifdef NI_NUMERICSCOPE
 496         if ((flags & NI_NUMERICSCOPE) != 0) {
 497                 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 498                 if (n < 0 || (size_t)n >= bufsiz)
 499                         return -1;
 500                 else
 501                         return n;
 502         }
 503 #endif
 504
 505         /* if_indextoname() does not take buffer size.  not a good api... */
 506         if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
 507             bufsiz >= IF_NAMESIZE) {
 508                 char *p = if_indextoname(ifindex, buf);
 509                 if (p) {
 510                         return (int)strlen(p);
 511                 }
 512         }
 513
 514         /* last resort */
 515         n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 516         if (n < 0 || (size_t) n >= bufsiz)
 517                 return -1;
 518         else
 519                 return n;
 520 }
 521 #endif /* INET6 */
 522
 523
 524 #if !defined(__minix)
 525 /*
 526  * getnameinfo_link():
 527  * Format a link-layer address into a printable format, paying attention to
 528  * the interface type.
 529  */
 530 /* ARGSUSED */
 531 static int
 532 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
 533     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 534     int flags)
 535 {
 536         const struct sockaddr_dl *sdl =
 537             (const struct sockaddr_dl *)(const void *)sa;
 538         const struct ieee1394_hwaddr *iha;
 539         int n;
 540
 541         if (serv != NULL && servlen > 0)
 542                 *serv = '\0';
 543
 544         if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
 545                 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
 546                 if (n < 0 || (socklen_t) n > hostlen) {
 547                         *host = '\0';
 548                         return EAI_MEMORY;
 549                 }
 550                 return 0;
 551         }
 552
 553         switch (sdl->sdl_type) {
 554 #ifdef IFT_ECONET
 555         case IFT_ECONET:
 556                 if (sdl->sdl_alen < 2)
 557                         return EAI_FAMILY;
 558                 if (CLLADDR(sdl)[1] == 0)
 559                         n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
 560                 else
 561                         n = snprintf(host, hostlen, "%u.%u",
 562                             CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
 563                 if (n < 0 || (socklen_t) n >= hostlen) {
 564                         *host = '\0';
 565                         return EAI_MEMORY;
 566                 } else
 567                         return 0;
 568 #endif
 569         case IFT_IEEE1394:
 570                 if (sdl->sdl_alen < sizeof(iha->iha_uid))
 571                         return EAI_FAMILY;
 572                 iha =
 573                     (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
 574                 return hexname(iha->iha_uid, sizeof(iha->iha_uid),
 575                     host, hostlen);
 576         /*
 577          * The following have zero-length addresses.
 578          * IFT_ATM      (net/if_atmsubr.c)
 579          * IFT_FAITH    (net/if_faith.c)
 580          * IFT_GIF      (net/if_gif.c)
 581          * IFT_LOOP     (net/if_loop.c)
 582          * IFT_PPP      (net/if_ppp.c, net/if_spppsubr.c)
 583          * IFT_SLIP     (net/if_sl.c, net/if_strip.c)
 584          * IFT_STF      (net/if_stf.c)
 585          * IFT_L2VLAN   (net/if_vlan.c)
 586          * IFT_PROPVIRTUAL (net/if_bridge.h>
 587          */
 588         /*
 589          * The following use IPv4 addresses as link-layer addresses:
 590          * IFT_OTHER    (net/if_gre.c)
 591          */
 592         case IFT_ARCNET: /* default below is believed correct for all these. */
 593         case IFT_ETHER:
 594         case IFT_FDDI:
 595         case IFT_HIPPI:
 596         case IFT_ISO88025:
 597         default:
 598                 return hexname((const uint8_t *)CLLADDR(sdl),
 599                     (size_t)sdl->sdl_alen, host, hostlen);
 600         }
 601 }
 602
 603 static int
 604 hexname(const uint8_t *cp, size_t len, char *host, socklen_t hostlen)
 605 {
 606         int n;
 607         size_t i;
 608         char *outp = host;
 609
 610         *outp = '\0';
 611         for (i = 0; i < len; i++) {
 612                 n = snprintf(outp, hostlen, "%s%02x",
 613                     i ? ":" : "", cp[i]);
 614                 if (n < 0 || (socklen_t) n >= hostlen) {
 615                         *host = '\0';
 616                         return EAI_MEMORY;
 617                 }
 618                 outp += n;
 619                 hostlen -= n;
 620         }
 621         return 0;
 622 }
 623 #endif /* !defined(__minix) */