lib/libc/net/getnameinfo.c

   1 /*      $NetBSD: getnameinfo.c,v 1.50 2010/06/29 14:44:19 seanb 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 1.50 2010/06/29 14:44:19 seanb 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 #ifndef __minix
  58 #include <net/if_dl.h>
  59 #include <net/if_ieee1394.h>
  60 #include <net/if_types.h>
  61 #include <netatalk/at.h>
  62 #endif /* !__minix */
  63 #include <netinet/in.h>
  64 #include <arpa/inet.h>
  65 #include <arpa/nameser.h>
  66 #include <assert.h>
  67 #include <limits.h>
  68 #include <netdb.h>
  69 #include <resolv.h>
  70 #include <stddef.h>
  71 #include <string.h>
  72
  73 #include "servent.h"
  74
  75 #ifdef __weak_alias
  76 __weak_alias(getnameinfo,_getnameinfo)
  77 #endif
  78
  79 static const struct afd {
  80         int             a_af;
  81         socklen_t       a_addrlen;
  82         socklen_t       a_socklen;
  83         int             a_off;
  84 } afdl [] = {
  85 #ifdef INET6
  86         {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
  87                 offsetof(struct sockaddr_in6, sin6_addr)},
  88 #endif
  89         {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
  90                 offsetof(struct sockaddr_in, sin_addr)},
  91         {0, 0, 0, 0},
  92 };
  93
  94 struct sockinet {
  95         u_char  si_len;
  96         u_char  si_family;
  97         u_short si_port;
  98 };
  99
 100 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
 101     socklen_t, char *, socklen_t, int));
 102 #ifdef INET6
 103 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
 104                                  socklen_t, int));
 105 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t,
 106                                  int));
 107 #endif
 108 #ifndef __minix
 109 static int getnameinfo_atalk __P((const struct sockaddr *, socklen_t, char *,
 110     socklen_t, char *, socklen_t, int));
 111
 112 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
 113     socklen_t, char *, socklen_t, int));
 114 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
 115 #endif /* __minix */
 116
 117 /*
 118  * Top-level getnameinfo() code.  Look at the address family, and pick an
 119  * appropriate function to call.
 120  */
 121 int
 122 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 123         const struct sockaddr *sa;
 124         socklen_t salen;
 125         char *host, *serv;
 126         socklen_t hostlen, 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 #endif /* !__minix */
 145         default:
 146                 return EAI_FAMILY;
 147         }
 148 }
 149
 150 #ifndef __minix
 151 /*
 152  * getnameinfo_atalk():
 153  * Format an AppleTalk address into a printable format.
 154  */
 155 /* ARGSUSED */
 156 static int
 157 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
 158     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 159     int flags)
 160 {
 161         char numserv[8];
 162         int n, m=0;
 163
 164         const struct sockaddr_at *sat =
 165             (const struct sockaddr_at *)(const void *)sa;
 166
 167         if (serv != NULL && servlen > 0) {
 168                 snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
 169                 if (strlen(numserv) + 1 > servlen)
 170                         return EAI_MEMORY;
 171                 strlcpy(serv, numserv, servlen);
 172         }
 173
 174         n = snprintf(host, hostlen, "%u.%u",
 175             ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
 176
 177         if (n < 0 || (socklen_t)(m+n) >= hostlen)
 178                 goto errout;
 179
 180         m += n;
 181
 182         if (sat->sat_range.r_netrange.nr_phase) {
 183                 n = snprintf(host+m, hostlen-m, " phase %u",
 184                         sat->sat_range.r_netrange.nr_phase);
 185
 186                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 187                         goto errout;
 188
 189                 m += n;
 190         }
 191         if (sat->sat_range.r_netrange.nr_firstnet) {
 192                 n = snprintf(host+m, hostlen-m, " range %u - %u",
 193                         ntohs(sat->sat_range.r_netrange.nr_firstnet),
 194                         ntohs(sat->sat_range.r_netrange.nr_lastnet ));
 195
 196                 if (n < 0 || (socklen_t)(m+n) >= hostlen)
 197                         goto errout;
 198
 199                 m += n;
 200         }
 201
 202         return 0;
 203
 204 errout:
 205         if (host && hostlen>0)
 206                 host[m] = '\0'; /* XXX ??? */
 207
 208         return EAI_MEMORY;
 209 }
 210 #endif /* !__minix */
 211
 212 /*
 213  * getnameinfo_inet():
 214  * Format an IPv4 or IPv6 sockaddr into a printable string.
 215  */
 216 static int
 217 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 218         const struct sockaddr *sa;
 219         socklen_t salen;
 220         char *host;
 221         socklen_t hostlen;
 222         char *serv;
 223         socklen_t servlen;
 224         int flags;
 225 {
 226         const struct afd *afd;
 227         struct servent *sp;
 228         struct hostent *hp;
 229         u_short port;
 230         int family, i;
 231         const char *addr;
 232         u_int32_t v4a;
 233         char numserv[512];
 234         char numaddr[512];
 235
 236         /* sa is checked below */
 237         /* host may be NULL */
 238         /* serv may be NULL */
 239
 240         if (sa == NULL)
 241                 return EAI_FAIL;
 242
 243         family = sa->sa_family;
 244         for (i = 0; afdl[i].a_af; i++)
 245                 if (afdl[i].a_af == family) {
 246                         afd = &afdl[i];
 247                         goto found;
 248                 }
 249         return EAI_FAMILY;
 250
 251  found:
 252         if (salen != afd->a_socklen)
 253                 return EAI_FAIL;
 254
 255         /* network byte order */
 256         port = ((const struct sockinet *)(const void *)sa)->si_port;
 257         addr = (const char *)(const void *)sa + afd->a_off;
 258
 259         if (serv == NULL || servlen == 0) {
 260                 /*
 261                  * do nothing in this case.
 262                  * in case you are wondering if "&&" is more correct than
 263                  * "||" here: rfc2553bis-03 says that serv == NULL OR
 264                  * servlen == 0 means that the caller does not want the result.
 265                  */
 266         } else {
 267                 struct servent_data svd;
 268                 struct servent sv;
 269
 270                 if (flags & NI_NUMERICSERV)
 271                         sp = NULL;
 272                 else {
 273                         (void)memset(&svd, 0, sizeof(svd));
 274                         sp = getservbyport_r(port,
 275                                 (flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
 276                 }
 277                 if (sp) {
 278                         if (strlen(sp->s_name) + 1 > servlen) {
 279                                 endservent_r(&svd);
 280                                 return EAI_MEMORY;
 281                         }
 282                         strlcpy(serv, sp->s_name, servlen);
 283                         endservent_r(&svd);
 284                 } else {
 285                         snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
 286                         if (strlen(numserv) + 1 > servlen)
 287                                 return EAI_MEMORY;
 288                         strlcpy(serv, numserv, servlen);
 289                 }
 290         }
 291
 292         switch (sa->sa_family) {
 293         case AF_INET:
 294                 v4a = (u_int32_t)
 295                     ntohl(((const struct sockaddr_in *)
 296                     (const void *)sa)->sin_addr.s_addr);
 297                 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 298                         flags |= NI_NUMERICHOST;
 299                 v4a >>= IN_CLASSA_NSHIFT;
 300                 if (v4a == 0)
 301                         flags |= NI_NUMERICHOST;
 302                 break;
 303 #ifdef INET6
 304         case AF_INET6:
 305             {
 306                 const struct sockaddr_in6 *sin6;
 307                 sin6 = (const struct sockaddr_in6 *)(const void *)sa;
 308                 switch (sin6->sin6_addr.s6_addr[0]) {
 309                 case 0x00:
 310                         if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 311                                 ;
 312                         else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 313                                 ;
 314                         else
 315                                 flags |= NI_NUMERICHOST;
 316                         break;
 317                 default:
 318                         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 319                                 flags |= NI_NUMERICHOST;
 320                         }
 321                         else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 322                                 flags |= NI_NUMERICHOST;
 323                         break;
 324                 }
 325             }
 326                 break;
 327 #endif
 328         }
 329         if (host == NULL || hostlen == 0) {
 330                 /*
 331                  * do nothing in this case.
 332                  * in case you are wondering if "&&" is more correct than
 333                  * "||" here: rfc2553bis-03 says that host == NULL or
 334                  * hostlen == 0 means that the caller does not want the result.
 335                  */
 336         } else if (flags & NI_NUMERICHOST) {
 337                 size_t numaddrlen;
 338
 339                 /* NUMERICHOST and NAMEREQD conflicts with each other */
 340                 if (flags & NI_NAMEREQD)
 341                         return EAI_NONAME;
 342
 343                 switch(afd->a_af) {
 344 #ifdef INET6
 345                 case AF_INET6:
 346                 {
 347                         int error;
 348
 349                         if ((error = ip6_parsenumeric(sa, addr, host,
 350                                                       hostlen, flags)) != 0)
 351                                 return(error);
 352                         break;
 353                 }
 354 #endif
 355                 default:
 356                         if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
 357                             == NULL)
 358                                 return EAI_SYSTEM;
 359                         numaddrlen = strlen(numaddr);
 360                         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 361                                 return EAI_MEMORY;
 362                         strlcpy(host, numaddr, hostlen);
 363                         break;
 364                 }
 365         } else {
 366                 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
 367
 368                 if (hp) {
 369 #if 0
 370                         /*
 371                          * commented out, since "for local host" is not
 372                          * implemented here - see RFC2553 p30
 373                          */
 374                         if (flags & NI_NOFQDN) {
 375                                 char *p;
 376                                 p = strchr(hp->h_name, '.');
 377                                 if (p)
 378                                         *p = '\0';
 379                         }
 380 #endif
 381                         if (strlen(hp->h_name) + 1 > hostlen) {
 382                                 return EAI_MEMORY;
 383                         }
 384                         strlcpy(host, hp->h_name, hostlen);
 385                 } else {
 386                         if (flags & NI_NAMEREQD)
 387                                 return EAI_NONAME;
 388                         switch(afd->a_af) {
 389 #ifdef INET6
 390                         case AF_INET6:
 391                         {
 392                                 int error;
 393
 394                                 if ((error = ip6_parsenumeric(sa, addr, host,
 395                                                               hostlen,
 396                                                               flags)) != 0)
 397                                         return(error);
 398                                 break;
 399                         }
 400 #endif
 401                         default:
 402                                 if (inet_ntop(afd->a_af, addr, host,
 403                                     hostlen) == NULL)
 404                                         return EAI_SYSTEM;
 405                                 break;
 406                         }
 407                 }
 408         }
 409         return(0);
 410 }
 411
 412 #ifdef INET6
 413 static int
 414 ip6_parsenumeric(sa, addr, host, hostlen, flags)
 415         const struct sockaddr *sa;
 416         const char *addr;
 417         char *host;
 418         socklen_t hostlen;
 419         int flags;
 420 {
 421         size_t numaddrlen;
 422         char numaddr[512];
 423
 424         _DIAGASSERT(sa != NULL);
 425         _DIAGASSERT(addr != NULL);
 426         _DIAGASSERT(host != NULL);
 427
 428         if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
 429                 return EAI_SYSTEM;
 430
 431         numaddrlen = strlen(numaddr);
 432         if (numaddrlen + 1 > hostlen) /* don't forget terminator */
 433                 return EAI_OVERFLOW;
 434         strlcpy(host, numaddr, hostlen);
 435
 436         if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
 437                 char zonebuf[MAXHOSTNAMELEN];
 438                 int zonelen;
 439
 440                 zonelen = ip6_sa2str(
 441                     (const struct sockaddr_in6 *)(const void *)sa,
 442                     zonebuf, sizeof(zonebuf), flags);
 443                 if (zonelen < 0)
 444                         return EAI_OVERFLOW;
 445                 if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
 446                         return EAI_OVERFLOW;
 447                 /* construct <numeric-addr><delim><zoneid> */
 448                 memcpy(host + numaddrlen + 1, zonebuf,
 449                     (size_t)zonelen);
 450                 host[numaddrlen] = SCOPE_DELIMITER;
 451                 host[numaddrlen + 1 + zonelen] = '\0';
 452         }
 453
 454         return 0;
 455 }
 456
 457 /* ARGSUSED */
 458 static int
 459 ip6_sa2str(sa6, buf, bufsiz, flags)
 460         const struct sockaddr_in6 *sa6;
 461         char *buf;
 462         size_t bufsiz;
 463         int flags;
 464 {
 465         unsigned int ifindex;
 466         const struct in6_addr *a6;
 467         int n;
 468
 469         _DIAGASSERT(sa6 != NULL);
 470         _DIAGASSERT(buf != NULL);
 471
 472         ifindex = (unsigned int)sa6->sin6_scope_id;
 473         a6 = &sa6->sin6_addr;
 474
 475 #ifdef NI_NUMERICSCOPE
 476         if ((flags & NI_NUMERICSCOPE) != 0) {
 477                 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 478                 if (n < 0 || (size_t)n >= bufsiz)
 479                         return -1;
 480                 else
 481                         return n;
 482         }
 483 #endif
 484
 485         /* if_indextoname() does not take buffer size.  not a good api... */
 486         if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
 487             bufsiz >= IF_NAMESIZE) {
 488                 char *p = if_indextoname(ifindex, buf);
 489                 if (p) {
 490                         return(strlen(p));
 491                 }
 492         }
 493
 494         /* last resort */
 495         n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
 496         if (n < 0 || (size_t) n >= bufsiz)
 497                 return -1;
 498         else
 499                 return n;
 500 }
 501 #endif /* INET6 */
 502
 503
 504 #ifndef __minix
 505 /*
 506  * getnameinfo_link():
 507  * Format a link-layer address into a printable format, paying attention to
 508  * the interface type.
 509  */
 510 /* ARGSUSED */
 511 static int
 512 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
 513     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
 514     int flags)
 515 {
 516         const struct sockaddr_dl *sdl =
 517             (const struct sockaddr_dl *)(const void *)sa;
 518         const struct ieee1394_hwaddr *iha;
 519         int n;
 520
 521         if (serv != NULL && servlen > 0)
 522                 *serv = '\0';
 523
 524         if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
 525                 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
 526                 if (n < 0 || (socklen_t) n > hostlen) {
 527                         *host = '\0';
 528                         return EAI_MEMORY;
 529                 }
 530                 return 0;
 531         }
 532
 533         switch (sdl->sdl_type) {
 534 #ifdef IFT_ECONET
 535         case IFT_ECONET:
 536                 if (sdl->sdl_alen < 2)
 537                         return EAI_FAMILY;
 538                 if (CLLADDR(sdl)[1] == 0)
 539                         n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
 540                 else
 541                         n = snprintf(host, hostlen, "%u.%u",
 542                             CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
 543                 if (n < 0 || (socklen_t) n >= hostlen) {
 544                         *host = '\0';
 545                         return EAI_MEMORY;
 546                 } else
 547                         return 0;
 548 #endif
 549         case IFT_IEEE1394:
 550                 if (sdl->sdl_alen < sizeof(iha->iha_uid))
 551                         return EAI_FAMILY;
 552                 iha =
 553                     (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
 554                 return hexname(iha->iha_uid, sizeof(iha->iha_uid),
 555                     host, hostlen);
 556         /*
 557          * The following have zero-length addresses.
 558          * IFT_ATM      (net/if_atmsubr.c)
 559          * IFT_FAITH    (net/if_faith.c)
 560          * IFT_GIF      (net/if_gif.c)
 561          * IFT_LOOP     (net/if_loop.c)
 562          * IFT_PPP      (net/if_ppp.c, net/if_spppsubr.c)
 563          * IFT_SLIP     (net/if_sl.c, net/if_strip.c)
 564          * IFT_STF      (net/if_stf.c)
 565          * IFT_L2VLAN   (net/if_vlan.c)
 566          * IFT_PROPVIRTUAL (net/if_bridge.h>
 567          */
 568         /*
 569          * The following use IPv4 addresses as link-layer addresses:
 570          * IFT_OTHER    (net/if_gre.c)
 571          */
 572         case IFT_ARCNET: /* default below is believed correct for all these. */
 573         case IFT_ETHER:
 574         case IFT_FDDI:
 575         case IFT_HIPPI:
 576         case IFT_ISO88025:
 577         default:
 578                 return hexname((const u_int8_t *)CLLADDR(sdl),
 579                     (size_t)sdl->sdl_alen, host, hostlen);
 580         }
 581 }
 582
 583 static int
 584 hexname(cp, len, host, hostlen)
 585         const u_int8_t *cp;
 586         char *host;
 587         size_t len;
 588         socklen_t hostlen;
 589 {
 590         int n;
 591         size_t i;
 592         char *outp = host;
 593
 594         *outp = '\0';
 595         for (i = 0; i < len; i++) {
 596                 n = snprintf(outp, hostlen, "%s%02x",
 597                     i ? ":" : "", cp[i]);
 598                 if (n < 0 || (socklen_t) n >= hostlen) {
 599                         *host = '\0';
 600                         return EAI_MEMORY;
 601                 }
 602                 outp += n;
 603                 hostlen -= n;
 604         }
 605         return 0;
 606 }
 607 #endif /* !__minix */