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 sin6 = (const struct sockaddr_in6 *)sa; 233 switch (sin6->sin6_addr.s6_addr[0]) { 234 case 0x00: 235 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 236 ; 237 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 238 ; 239 else 240 flags |= NI_NUMERICHOST; 241 break; 242 default: 243 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 244 flags |= NI_NUMERICHOST; 245 } 246 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 247 flags |= NI_NUMERICHOST; 248 break; 249 } 250 } 251 break; 252 #endif 253 } 254 if (host == NULL || hostlen == 0) { 255 /* 256 * do nothing in this case. 257 * in case you are wondering if "&&" is more correct than 258 * "||" here: rfc2553bis-03 says that host == NULL or 259 * hostlen == 0 means that the caller does not want the result. 260 */ 261 } else if (flags & NI_NUMERICHOST) { 262 size_t numaddrlen; 263 264 /* NUMERICHOST and NAMEREQD conflicts with each other */ 265 if (flags & NI_NAMEREQD) 266 return EAI_NONAME; 267 268 switch(afd->a_af) { 269 #ifdef INET6 270 case AF_INET6: 271 { 272 int error; 273 274 if ((error = ip6_parsenumeric(sa, addr, host, 275 hostlen, flags)) != 0) 276 return(error); 277 break; 278 } 279 #endif 280 default: 281 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 282 == NULL) 283 return EAI_SYSTEM; 284 numaddrlen = strlen(numaddr); 285 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 286 return EAI_MEMORY; 287 strlcpy(host, numaddr, hostlen); 288 break; 289 } 290 } else { 291 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 292 293 if (hp) { 294 #if 0 295 /* 296 * commented out, since "for local host" is not 297 * implemented here - see RFC2553 p30 298 */ 299 if (flags & NI_NOFQDN) { 300 char *p; 301 p = strchr(hp->h_name, '.'); 302 if (p) 303 *p = '\0'; 304 } 305 #endif 306 if (strlen(hp->h_name) + 1 > hostlen) { 307 freehostent(hp); 308 return EAI_MEMORY; 309 } 310 strlcpy(host, hp->h_name, hostlen); 311 freehostent(hp); 312 } else { 313 if (flags & NI_NAMEREQD) 314 return EAI_NONAME; 315 switch(afd->a_af) { 316 #ifdef INET6 317 case AF_INET6: 318 { 319 int error; 320 321 if ((error = ip6_parsenumeric(sa, addr, host, 322 hostlen, 323 flags)) != 0) 324 return(error); 325 break; 326 } 327 #endif 328 default: 329 if (inet_ntop(afd->a_af, addr, host, 330 hostlen) == NULL) 331 return EAI_SYSTEM; 332 break; 333 } 334 } 335 } 336 return(0); 337 } 338 339 #ifdef INET6 340 static int 341 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, 342 char *host, size_t hostlen, int flags) 343 { 344 size_t numaddrlen; 345 char numaddr[512]; 346 347 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 348 return EAI_SYSTEM; 349 350 numaddrlen = strlen(numaddr); 351 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 352 return EAI_OVERFLOW; 353 strlcpy(host, numaddr, hostlen); 354 355 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 356 char zonebuf[MAXHOSTNAMELEN]; 357 int zonelen; 358 359 zonelen = ip6_sa2str( 360 (const struct sockaddr_in6 *)(const void *)sa, 361 zonebuf, sizeof(zonebuf), flags); 362 if (zonelen < 0) 363 return EAI_OVERFLOW; 364 if (zonelen + 1 + numaddrlen + 1 > hostlen) 365 return EAI_OVERFLOW; 366 367 /* construct <numeric-addr><delim><zoneid> */ 368 memcpy(host + numaddrlen + 1, zonebuf, 369 (size_t)zonelen); 370 host[numaddrlen] = SCOPE_DELIMITER; 371 host[numaddrlen + 1 + zonelen] = '\0'; 372 } 373 374 return 0; 375 } 376 377 /* ARGSUSED */ 378 static int 379 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 380 { 381 unsigned int ifindex; 382 const struct in6_addr *a6; 383 int n; 384 385 ifindex = (unsigned int)sa6->sin6_scope_id; 386 a6 = &sa6->sin6_addr; 387 388 if ((flags & NI_NUMERICSCOPE) != 0) { 389 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 390 if (n < 0 || n >= bufsiz) 391 return -1; 392 else 393 return n; 394 } 395 396 /* if_indextoname() does not take buffer size. not a good api... */ 397 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 398 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 399 char *p = if_indextoname(ifindex, buf); 400 if (p) { 401 return(strlen(p)); 402 } 403 } 404 405 /* last resort */ 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 /* INET6 */ 413 414 /* 415 * getnameinfo_link(): 416 * Format a link-layer address into a printable format, paying attention to 417 * the interface type. 418 */ 419 /* ARGSUSED */ 420 static int 421 getnameinfo_link(const struct afd *afd, 422 const struct sockaddr *sa, socklen_t salen, 423 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 424 { 425 const struct sockaddr_dl *sdl = 426 (const struct sockaddr_dl *)(const void *)sa; 427 const struct fw_hwaddr *iha; 428 int n; 429 430 if (serv != NULL && servlen > 0) 431 *serv = '\0'; 432 433 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 434 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 435 if (n >= hostlen) { 436 *host = '\0'; 437 return (EAI_MEMORY); 438 } 439 return (0); 440 } 441 442 if (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0) { 443 n = sdl->sdl_nlen; 444 if (n >= hostlen) { 445 *host = '\0'; 446 return (EAI_MEMORY); 447 } 448 memcpy(host, sdl->sdl_data, sdl->sdl_nlen); 449 host[n] = '\0'; 450 return (0); 451 } 452 453 switch (sdl->sdl_type) { 454 case IFT_IEEE1394: 455 if (sdl->sdl_alen < sizeof(iha->sender_unique_ID_hi) + 456 sizeof(iha->sender_unique_ID_lo)) 457 return EAI_FAMILY; 458 iha = (const struct fw_hwaddr *)(const void *)LLADDR(sdl); 459 return hexname((const u_int8_t *)&iha->sender_unique_ID_hi, 460 sizeof(iha->sender_unique_ID_hi) + 461 sizeof(iha->sender_unique_ID_lo), 462 host, hostlen); 463 /* 464 * The following have zero-length addresses. 465 * IFT_GIF (net/if_gif.c) 466 * IFT_LOOP (net/if_loop.c) 467 * IFT_PPP (net/if_tuntap.c) 468 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 469 * IFT_STF (net/if_stf.c) 470 * IFT_L2VLAN (net/if_vlan.c) 471 * IFT_BRIDGE (net/if_bridge.h> 472 */ 473 /* 474 * The following use IPv4 addresses as link-layer addresses: 475 * IFT_OTHER (net/if_gre.c) 476 * IFT_OTHER (netinet/ip_ipip.c) 477 */ 478 /* default below is believed correct for all these. */ 479 case IFT_ETHER: 480 case IFT_FDDI: 481 case IFT_HIPPI: 482 case IFT_ISO88025: 483 default: 484 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 485 host, hostlen); 486 } 487 } 488 489 static int 490 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen) 491 { 492 int i, n; 493 char *outp = host; 494 495 *outp = '\0'; 496 for (i = 0; i < len; i++) { 497 n = snprintf(outp, hostlen, "%s%02x", 498 i ? ":" : "", cp[i]); 499 if (n < 0 || n >= hostlen) { 500 *host = '\0'; 501 return EAI_MEMORY; 502 } 503 outp += n; 504 hostlen -= n; 505 } 506 return 0; 507 } 508 509 /* 510 * getnameinfo_un(): 511 * Format a UNIX IPC domain address (pathname). 512 */ 513 /* ARGSUSED */ 514 static int 515 getnameinfo_un(const struct afd *afd, 516 const struct sockaddr *sa, socklen_t salen, 517 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 518 { 519 size_t pathlen; 520 521 if (serv != NULL && servlen > 0) 522 *serv = '\0'; 523 if (host != NULL && hostlen > 0) { 524 pathlen = salen - afd->a_off; 525 526 if (pathlen + 1 > hostlen) { 527 *host = '\0'; 528 return (EAI_MEMORY); 529 } 530 strlcpy(host, (const char *)sa + afd->a_off, pathlen + 1); 531 } 532 533 return (0); 534 } 535