1 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * Copyright (c) 2000 Ben Harris. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the project nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * Issues to be discussed: 37 * - Thread safe-ness must be checked 38 * - RFC2553 says that we should raise error on short buffer. X/Open says 39 * we need to truncate the result. We obey RFC2553 (and X/Open should be 40 * modified). ipngwg rough consensus seems to follow RFC2553. 41 * - What is "local" in NI_FQDN? 42 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other. 43 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if 44 * sin6_scope_id is filled - standardization status? 45 * XXX breaks backward compat for code that expects no scopeid. 46 * beware on merge. 47 */ 48 49 #include <sys/types.h> 50 #include <sys/socket.h> 51 #include <sys/un.h> 52 #include <net/if.h> 53 #include <net/if_dl.h> 54 #include <net/if_types.h> 55 #include <net/firewire.h> 56 #include <netinet/in.h> 57 #include <arpa/inet.h> 58 #include <arpa/nameser.h> 59 #include <netdb.h> 60 #include <resolv.h> 61 #include <string.h> 62 #include <stddef.h> 63 #include <errno.h> 64 65 static const struct afd *find_afd(int); 66 static int getnameinfo_inet(const struct afd *, 67 const struct sockaddr *, socklen_t, char *, 68 size_t, char *, size_t, int); 69 #ifdef INET6 70 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 71 size_t, int); 72 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 73 #endif 74 static int getnameinfo_link(const struct afd *, 75 const struct sockaddr *, socklen_t, char *, 76 size_t, char *, size_t, int); 77 static int hexname(const u_int8_t *, size_t, char *, size_t); 78 static int getnameinfo_un(const struct afd *, 79 const struct sockaddr *, socklen_t, char *, 80 size_t, char *, size_t, int); 81 82 static const struct afd { 83 int a_af; 84 size_t a_addrlen; 85 socklen_t a_socklen; 86 int a_off; 87 int (*a_func)(const struct afd *, 88 const struct sockaddr *, socklen_t, char *, 89 size_t, char *, size_t, int); 90 } afdl [] = { 91 #ifdef INET6 92 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 93 offsetof(struct sockaddr_in6, sin6_addr), 94 getnameinfo_inet}, 95 #endif 96 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 97 offsetof(struct sockaddr_in, sin_addr), 98 getnameinfo_inet}, 99 #define sizeofmember(type, member) (sizeof(((type *)0)->member)) 100 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path), 101 sizeof(struct sockaddr_un), 102 offsetof(struct sockaddr_un, sun_path), 103 getnameinfo_un}, 104 {PF_LINK, sizeofmember(struct sockaddr_dl, sdl_data), 105 sizeof(struct sockaddr_dl), 106 offsetof(struct sockaddr_dl, sdl_data), 107 getnameinfo_link}, 108 {0, 0, 0}, 109 }; 110 111 int 112 getnameinfo(const struct sockaddr *sa, socklen_t salen, 113 char *host, size_t hostlen, char *serv, size_t servlen, 114 int flags) 115 { 116 const struct afd *afd; 117 118 if (sa == NULL) 119 return (EAI_FAIL); 120 121 afd = find_afd(sa->sa_family); 122 if (afd == NULL) 123 return (EAI_FAMILY); 124 /* 125 * getnameinfo() accepts an salen of sizeof(struct sockaddr_storage) 126 * at maximum as shown in RFC 4038 Sec.6.2.3. 127 */ 128 if (salen > sizeof(struct sockaddr_storage)) 129 return (EAI_FAMILY); 130 131 switch (sa->sa_family) { 132 case PF_LOCAL: 133 /* 134 * PF_LOCAL uses variable salen depending on the 135 * content length of sun_path. Require 1 byte in 136 * sun_path at least. 137 */ 138 if (salen <= afd->a_socklen - 139 sizeofmember(struct sockaddr_un, sun_path)) 140 return (EAI_FAMILY); 141 else if (salen > afd->a_socklen) 142 salen = afd->a_socklen; 143 break; 144 case PF_LINK: 145 if (salen <= afd->a_socklen - 146 sizeofmember(struct sockaddr_dl, sdl_data)) 147 return (EAI_FAMILY); 148 break; 149 default: 150 if (salen < afd->a_socklen) 151 return (EAI_FAMILY); 152 else 153 salen = afd->a_socklen; 154 break; 155 } 156 157 return ((*afd->a_func)(afd, sa, salen, host, hostlen, 158 serv, servlen, flags)); 159 } 160 161 static const struct afd * 162 find_afd(int af) 163 { 164 const struct afd *afd; 165 166 if (af == PF_UNSPEC) 167 return (NULL); 168 for (afd = &afdl[0]; afd->a_af > 0; afd++) { 169 if (afd->a_af == af) 170 return (afd); 171 } 172 return (NULL); 173 } 174 175 static int 176 getnameinfo_inet(const struct afd *afd, 177 const struct sockaddr *sa, socklen_t salen, 178 char *host, size_t hostlen, char *serv, size_t servlen, 179 int flags) 180 { 181 struct servent *sp; 182 struct hostent *hp; 183 u_short port; 184 const char *addr; 185 u_int32_t v4a; 186 int h_error; 187 char numserv[512]; 188 char numaddr[512]; 189 190 /* network byte order */ 191 port = ((const struct sockaddr_in *)sa)->sin_port; 192 addr = (const char *)sa + afd->a_off; 193 194 if (serv == NULL || servlen == 0) { 195 /* 196 * do nothing in this case. 197 * in case you are wondering if "&&" is more correct than 198 * "||" here: rfc2553bis-03 says that serv == NULL OR 199 * servlen == 0 means that the caller does not want the result. 200 */ 201 } else { 202 if (flags & NI_NUMERICSERV) 203 sp = NULL; 204 else { 205 sp = getservbyport(port, 206 (flags & NI_DGRAM) ? "udp" : "tcp"); 207 } 208 if (sp) { 209 if (strlen(sp->s_name) + 1 > servlen) 210 return EAI_MEMORY; 211 strlcpy(serv, sp->s_name, servlen); 212 } else { 213 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 214 if (strlen(numserv) + 1 > servlen) 215 return EAI_MEMORY; 216 strlcpy(serv, numserv, servlen); 217 } 218 } 219 220 switch (sa->sa_family) { 221 case AF_INET: 222 v4a = (u_int32_t) 223 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 224 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a) || 225 IN_ZERONET(v4a)) 226 flags |= NI_NUMERICHOST; 227 break; 228 #ifdef INET6 229 case AF_INET6: 230 { 231 const struct sockaddr_in6 *sin6; 232 233 sin6 = (const struct sockaddr_in6 *)sa; 234 235 /* 236 * https://pubs.opengroup.org/onlinepubs/9699919799/functions/getnameinfo.html 237 * "[IP6] [Option Start] If the socket address structure 238 * contains an IPv4-mapped IPv6 address or an IPv4-compatible 239 * IPv6 address, the implementation shall extract the embedded 240 * IPv4 address and lookup the node name for that IPv4 address. 241 * [Option End]" 242 * => getipnodebyaddr() handles this case for us. 243 * => in case of NI_NUMERICHOST being set, inet_ntop[6] will 244 * handle it too. 245 * 246 * "If the address is the IPv6 unspecified address ( "::" ), 247 * a lookup shall not be performed and the behavior shall be 248 * the same as when the node's name cannot be located." 249 * => getipnodebyaddr() handles this case for us. 250 * => in case of NI_NUMERICHOST being set, 251 * ip6_parsenumeric() -> inet_ntop[6] will handle it too. 252 */ 253 254 /* 255 * We used to exclude link-local from lookups. 256 * Even though calles in the resolver chain may not (yet) 257 * properly deal with them, we no longer do as for link-local 258 * there is a path to resolve these. See: 259 * RFC 6303 4.5. IPv6 Link-Local Addresses 260 * RFC 6762 4. Reverse Address Mapping 261 * 262 * XXX For IPv6 MC the only reference found was 263 * https://www.ietf.org/archive/id/draft-michaelson-as112-ipv6-02.html 264 * but there are also no "empty zone"s for x.0.f.f.ip6.arpa 265 * in DNS servers. Keep catching it here for now and 266 * do not attempt name resolution but return the address string. 267 */ 268 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 269 flags |= NI_NUMERICHOST; 270 } 271 break; 272 #endif 273 } 274 if (host == NULL || hostlen == 0) { 275 /* 276 * do nothing in this case. 277 * in case you are wondering if "&&" is more correct than 278 * "||" here: rfc2553bis-03 says that host == NULL or 279 * hostlen == 0 means that the caller does not want the result. 280 */ 281 } else if (flags & NI_NUMERICHOST) { 282 size_t numaddrlen; 283 284 /* NUMERICHOST and NAMEREQD conflicts with each other */ 285 if (flags & NI_NAMEREQD) 286 return EAI_NONAME; 287 288 switch(afd->a_af) { 289 #ifdef INET6 290 case AF_INET6: 291 { 292 int error; 293 294 if ((error = ip6_parsenumeric(sa, addr, host, 295 hostlen, flags)) != 0) 296 return(error); 297 break; 298 } 299 #endif 300 default: 301 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 302 == NULL) 303 return EAI_SYSTEM; 304 numaddrlen = strlen(numaddr); 305 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 306 return EAI_MEMORY; 307 strlcpy(host, numaddr, hostlen); 308 break; 309 } 310 } else { 311 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 312 313 if (hp) { 314 #if 0 315 /* 316 * commented out, since "for local host" is not 317 * implemented here - see RFC2553 p30 318 */ 319 if (flags & NI_NOFQDN) { 320 char *p; 321 p = strchr(hp->h_name, '.'); 322 if (p) 323 *p = '\0'; 324 } 325 #endif 326 if (strlen(hp->h_name) + 1 > hostlen) { 327 freehostent(hp); 328 return EAI_MEMORY; 329 } 330 strlcpy(host, hp->h_name, hostlen); 331 freehostent(hp); 332 } else { 333 if (flags & NI_NAMEREQD) 334 return EAI_NONAME; 335 switch(afd->a_af) { 336 #ifdef INET6 337 case AF_INET6: 338 { 339 int error; 340 341 if ((error = ip6_parsenumeric(sa, addr, host, 342 hostlen, 343 flags)) != 0) 344 return(error); 345 break; 346 } 347 #endif 348 default: 349 if (inet_ntop(afd->a_af, addr, host, 350 hostlen) == NULL) 351 return EAI_SYSTEM; 352 break; 353 } 354 } 355 } 356 return(0); 357 } 358 359 #ifdef INET6 360 static int 361 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, 362 char *host, size_t hostlen, int flags) 363 { 364 size_t numaddrlen; 365 char numaddr[512]; 366 367 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 368 return EAI_SYSTEM; 369 370 numaddrlen = strlen(numaddr); 371 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 372 return EAI_OVERFLOW; 373 strlcpy(host, numaddr, hostlen); 374 375 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 376 char zonebuf[MAXHOSTNAMELEN]; 377 int zonelen; 378 379 zonelen = ip6_sa2str( 380 (const struct sockaddr_in6 *)(const void *)sa, 381 zonebuf, sizeof(zonebuf), flags); 382 if (zonelen < 0) 383 return EAI_OVERFLOW; 384 if (zonelen + 1 + numaddrlen + 1 > hostlen) 385 return EAI_OVERFLOW; 386 387 /* construct <numeric-addr><delim><zoneid> */ 388 memcpy(host + numaddrlen + 1, zonebuf, 389 (size_t)zonelen); 390 host[numaddrlen] = SCOPE_DELIMITER; 391 host[numaddrlen + 1 + zonelen] = '\0'; 392 } 393 394 return 0; 395 } 396 397 /* ARGSUSED */ 398 static int 399 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 400 { 401 unsigned int ifindex; 402 const struct in6_addr *a6; 403 int n; 404 405 ifindex = (unsigned int)sa6->sin6_scope_id; 406 a6 = &sa6->sin6_addr; 407 408 if ((flags & NI_NUMERICSCOPE) != 0) { 409 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 410 if (n < 0 || n >= bufsiz) 411 return -1; 412 else 413 return n; 414 } 415 416 /* if_indextoname() does not take buffer size. not a good api... */ 417 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 418 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 419 char *p = if_indextoname(ifindex, buf); 420 if (p) { 421 return(strlen(p)); 422 } 423 } 424 425 /* last resort */ 426 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 427 if (n < 0 || (size_t)n >= bufsiz) 428 return -1; 429 else 430 return n; 431 } 432 #endif /* INET6 */ 433 434 /* 435 * getnameinfo_link(): 436 * Format a link-layer address into a printable format, paying attention to 437 * the interface type. 438 */ 439 /* ARGSUSED */ 440 static int 441 getnameinfo_link(const struct afd *afd, 442 const struct sockaddr *sa, socklen_t salen, 443 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 444 { 445 const struct sockaddr_dl *sdl = 446 (const struct sockaddr_dl *)(const void *)sa; 447 const struct fw_hwaddr *iha; 448 int n; 449 450 if (serv != NULL && servlen > 0) 451 *serv = '\0'; 452 453 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 454 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 455 if (n >= hostlen) { 456 *host = '\0'; 457 return (EAI_MEMORY); 458 } 459 return (0); 460 } 461 462 if (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0) { 463 n = sdl->sdl_nlen; 464 if (n >= hostlen) { 465 *host = '\0'; 466 return (EAI_MEMORY); 467 } 468 memcpy(host, sdl->sdl_data, sdl->sdl_nlen); 469 host[n] = '\0'; 470 return (0); 471 } 472 473 switch (sdl->sdl_type) { 474 case IFT_IEEE1394: 475 if (sdl->sdl_alen < sizeof(iha->sender_unique_ID_hi) + 476 sizeof(iha->sender_unique_ID_lo)) 477 return EAI_FAMILY; 478 iha = (const struct fw_hwaddr *)(const void *)LLADDR(sdl); 479 return hexname((const u_int8_t *)&iha->sender_unique_ID_hi, 480 sizeof(iha->sender_unique_ID_hi) + 481 sizeof(iha->sender_unique_ID_lo), 482 host, hostlen); 483 /* 484 * The following have zero-length addresses. 485 * IFT_GIF (net/if_gif.c) 486 * IFT_LOOP (net/if_loop.c) 487 * IFT_PPP (net/if_tuntap.c) 488 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 489 * IFT_STF (net/if_stf.c) 490 * IFT_L2VLAN (net/if_vlan.c) 491 * IFT_BRIDGE (net/if_bridge.h> 492 */ 493 /* 494 * The following use IPv4 addresses as link-layer addresses: 495 * IFT_OTHER (net/if_gre.c) 496 * IFT_OTHER (netinet/ip_ipip.c) 497 */ 498 /* default below is believed correct for all these. */ 499 case IFT_ETHER: 500 case IFT_FDDI: 501 case IFT_HIPPI: 502 case IFT_ISO88025: 503 default: 504 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 505 host, hostlen); 506 } 507 } 508 509 static int 510 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen) 511 { 512 int i, n; 513 char *outp = host; 514 515 *outp = '\0'; 516 for (i = 0; i < len; i++) { 517 n = snprintf(outp, hostlen, "%s%02x", 518 i ? ":" : "", cp[i]); 519 if (n < 0 || n >= hostlen) { 520 *host = '\0'; 521 return EAI_MEMORY; 522 } 523 outp += n; 524 hostlen -= n; 525 } 526 return 0; 527 } 528 529 /* 530 * getnameinfo_un(): 531 * Format a UNIX IPC domain address (pathname). 532 */ 533 /* ARGSUSED */ 534 static int 535 getnameinfo_un(const struct afd *afd, 536 const struct sockaddr *sa, socklen_t salen, 537 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 538 { 539 size_t pathlen; 540 541 if (serv != NULL && servlen > 0) 542 *serv = '\0'; 543 if (host != NULL && hostlen > 0) { 544 pathlen = salen - afd->a_off; 545 546 if (pathlen + 1 > hostlen) { 547 *host = '\0'; 548 return (EAI_MEMORY); 549 } 550 strlcpy(host, (const char *)sa + afd->a_off, pathlen + 1); 551 } 552 553 return (0); 554 } 555