1 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * Copyright (c) 2000 Ben Harris. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * Issues to be discussed: 35 * - Thread safe-ness must be checked 36 * - RFC2553 says that we should raise error on short buffer. X/Open says 37 * we need to truncate the result. We obey RFC2553 (and X/Open should be 38 * modified). ipngwg rough consensus seems to follow RFC2553. 39 * - What is "local" in NI_FQDN? 40 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other. 41 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if 42 * sin6_scope_id is filled - standardization status? 43 * XXX breaks backward compat for code that expects no scopeid. 44 * beware on merge. 45 */ 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 #include <sys/types.h> 51 #include <sys/socket.h> 52 #include <sys/un.h> 53 #include <net/if.h> 54 #include <net/if_dl.h> 55 #include <net/if_types.h> 56 #include <net/firewire.h> 57 #include <netinet/in.h> 58 #include <arpa/inet.h> 59 #include <arpa/nameser.h> 60 #include <netdb.h> 61 #include <resolv.h> 62 #include <string.h> 63 #include <stddef.h> 64 #include <errno.h> 65 66 static const struct afd *find_afd(int); 67 static int getnameinfo_inet(const struct afd *, 68 const struct sockaddr *, socklen_t, char *, 69 size_t, char *, size_t, int); 70 #ifdef INET6 71 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 72 size_t, int); 73 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 74 #endif 75 static int getnameinfo_link(const struct afd *, 76 const struct sockaddr *, socklen_t, char *, 77 size_t, char *, size_t, int); 78 static int hexname(const u_int8_t *, size_t, char *, size_t); 79 static int getnameinfo_un(const struct afd *, 80 const struct sockaddr *, socklen_t, char *, 81 size_t, char *, size_t, int); 82 83 static const struct afd { 84 int a_af; 85 size_t a_addrlen; 86 socklen_t a_socklen; 87 int a_off; 88 int (*a_func)(const struct afd *, 89 const struct sockaddr *, socklen_t, char *, 90 size_t, char *, size_t, int); 91 } afdl [] = { 92 #ifdef INET6 93 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 94 offsetof(struct sockaddr_in6, sin6_addr), 95 getnameinfo_inet}, 96 #endif 97 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 98 offsetof(struct sockaddr_in, sin_addr), 99 getnameinfo_inet}, 100 #define sizeofmember(type, member) (sizeof(((type *)0)->member)) 101 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path), 102 sizeof(struct sockaddr_un), 103 offsetof(struct sockaddr_un, sun_path), 104 getnameinfo_un}, 105 {PF_LINK, sizeofmember(struct sockaddr_dl, sdl_data), 106 sizeof(struct sockaddr_dl), 107 offsetof(struct sockaddr_dl, sdl_data), 108 getnameinfo_link}, 109 {0, 0, 0}, 110 }; 111 112 int 113 getnameinfo(const struct sockaddr *sa, socklen_t salen, 114 char *host, size_t hostlen, char *serv, size_t servlen, 115 int flags) 116 { 117 const struct afd *afd; 118 119 if (sa == NULL) 120 return (EAI_FAIL); 121 122 afd = find_afd(sa->sa_family); 123 if (afd == NULL) 124 return (EAI_FAMILY); 125 switch (sa->sa_family) { 126 case PF_LOCAL: 127 /* 128 * PF_LOCAL uses variable sa->sa_len depending on the 129 * content length of sun_path. Require 1 byte in 130 * sun_path at least. 131 */ 132 if (salen > afd->a_socklen || 133 salen <= afd->a_socklen - 134 sizeofmember(struct sockaddr_un, sun_path)) 135 return (EAI_FAIL); 136 break; 137 case PF_LINK: 138 if (salen <= afd->a_socklen - 139 sizeofmember(struct sockaddr_dl, sdl_data)) 140 return (EAI_FAIL); 141 break; 142 default: 143 if (salen != afd->a_socklen) 144 return (EAI_FAIL); 145 break; 146 } 147 148 return ((*afd->a_func)(afd, sa, salen, host, hostlen, 149 serv, servlen, flags)); 150 } 151 152 static const struct afd * 153 find_afd(int af) 154 { 155 const struct afd *afd; 156 157 if (af == PF_UNSPEC) 158 return (NULL); 159 for (afd = &afdl[0]; afd->a_af > 0; afd++) { 160 if (afd->a_af == af) 161 return (afd); 162 } 163 return (NULL); 164 } 165 166 static int 167 getnameinfo_inet(const struct afd *afd, 168 const struct sockaddr *sa, socklen_t salen, 169 char *host, size_t hostlen, char *serv, size_t servlen, 170 int flags) 171 { 172 struct servent *sp; 173 struct hostent *hp; 174 u_short port; 175 const char *addr; 176 u_int32_t v4a; 177 int h_error; 178 char numserv[512]; 179 char numaddr[512]; 180 181 /* network byte order */ 182 port = ((const struct sockaddr_in *)sa)->sin_port; 183 addr = (const char *)sa + afd->a_off; 184 185 if (serv == NULL || servlen == 0) { 186 /* 187 * do nothing in this case. 188 * in case you are wondering if "&&" is more correct than 189 * "||" here: rfc2553bis-03 says that serv == NULL OR 190 * servlen == 0 means that the caller does not want the result. 191 */ 192 } else { 193 if (flags & NI_NUMERICSERV) 194 sp = NULL; 195 else { 196 sp = getservbyport(port, 197 (flags & NI_DGRAM) ? "udp" : "tcp"); 198 } 199 if (sp) { 200 if (strlen(sp->s_name) + 1 > servlen) 201 return EAI_MEMORY; 202 strlcpy(serv, sp->s_name, servlen); 203 } else { 204 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 205 if (strlen(numserv) + 1 > servlen) 206 return EAI_MEMORY; 207 strlcpy(serv, numserv, servlen); 208 } 209 } 210 211 switch (sa->sa_family) { 212 case AF_INET: 213 v4a = (u_int32_t) 214 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 215 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 216 flags |= NI_NUMERICHOST; 217 v4a >>= IN_CLASSA_NSHIFT; 218 if (v4a == 0) 219 flags |= NI_NUMERICHOST; 220 break; 221 #ifdef INET6 222 case AF_INET6: 223 { 224 const struct sockaddr_in6 *sin6; 225 sin6 = (const struct sockaddr_in6 *)sa; 226 switch (sin6->sin6_addr.s6_addr[0]) { 227 case 0x00: 228 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 229 ; 230 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 231 ; 232 else 233 flags |= NI_NUMERICHOST; 234 break; 235 default: 236 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 237 flags |= NI_NUMERICHOST; 238 } 239 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 240 flags |= NI_NUMERICHOST; 241 break; 242 } 243 } 244 break; 245 #endif 246 } 247 if (host == NULL || hostlen == 0) { 248 /* 249 * do nothing in this case. 250 * in case you are wondering if "&&" is more correct than 251 * "||" here: rfc2553bis-03 says that host == NULL or 252 * hostlen == 0 means that the caller does not want the result. 253 */ 254 } else if (flags & NI_NUMERICHOST) { 255 size_t numaddrlen; 256 257 /* NUMERICHOST and NAMEREQD conflicts with each other */ 258 if (flags & NI_NAMEREQD) 259 return EAI_NONAME; 260 261 switch(afd->a_af) { 262 #ifdef INET6 263 case AF_INET6: 264 { 265 int error; 266 267 if ((error = ip6_parsenumeric(sa, addr, host, 268 hostlen, flags)) != 0) 269 return(error); 270 break; 271 } 272 #endif 273 default: 274 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 275 == NULL) 276 return EAI_SYSTEM; 277 numaddrlen = strlen(numaddr); 278 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 279 return EAI_MEMORY; 280 strlcpy(host, numaddr, hostlen); 281 break; 282 } 283 } else { 284 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 285 286 if (hp) { 287 #if 0 288 /* 289 * commented out, since "for local host" is not 290 * implemented here - see RFC2553 p30 291 */ 292 if (flags & NI_NOFQDN) { 293 char *p; 294 p = strchr(hp->h_name, '.'); 295 if (p) 296 *p = '\0'; 297 } 298 #endif 299 if (strlen(hp->h_name) + 1 > hostlen) { 300 freehostent(hp); 301 return EAI_MEMORY; 302 } 303 strlcpy(host, hp->h_name, hostlen); 304 freehostent(hp); 305 } else { 306 if (flags & NI_NAMEREQD) 307 return EAI_NONAME; 308 switch(afd->a_af) { 309 #ifdef INET6 310 case AF_INET6: 311 { 312 int error; 313 314 if ((error = ip6_parsenumeric(sa, addr, host, 315 hostlen, 316 flags)) != 0) 317 return(error); 318 break; 319 } 320 #endif 321 default: 322 if (inet_ntop(afd->a_af, addr, host, 323 hostlen) == NULL) 324 return EAI_SYSTEM; 325 break; 326 } 327 } 328 } 329 return(0); 330 } 331 332 #ifdef INET6 333 static int 334 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, 335 char *host, size_t hostlen, int flags) 336 { 337 size_t numaddrlen; 338 char numaddr[512]; 339 340 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 341 return EAI_SYSTEM; 342 343 numaddrlen = strlen(numaddr); 344 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 345 return EAI_OVERFLOW; 346 strlcpy(host, numaddr, hostlen); 347 348 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 349 char zonebuf[MAXHOSTNAMELEN]; 350 int zonelen; 351 352 zonelen = ip6_sa2str( 353 (const struct sockaddr_in6 *)(const void *)sa, 354 zonebuf, sizeof(zonebuf), flags); 355 if (zonelen < 0) 356 return EAI_OVERFLOW; 357 if (zonelen + 1 + numaddrlen + 1 > hostlen) 358 return EAI_OVERFLOW; 359 360 /* construct <numeric-addr><delim><zoneid> */ 361 memcpy(host + numaddrlen + 1, zonebuf, 362 (size_t)zonelen); 363 host[numaddrlen] = SCOPE_DELIMITER; 364 host[numaddrlen + 1 + zonelen] = '\0'; 365 } 366 367 return 0; 368 } 369 370 /* ARGSUSED */ 371 static int 372 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 373 { 374 unsigned int ifindex; 375 const struct in6_addr *a6; 376 int n; 377 378 ifindex = (unsigned int)sa6->sin6_scope_id; 379 a6 = &sa6->sin6_addr; 380 381 if ((flags & NI_NUMERICSCOPE) != 0) { 382 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 383 if (n < 0 || n >= bufsiz) 384 return -1; 385 else 386 return n; 387 } 388 389 /* if_indextoname() does not take buffer size. not a good api... */ 390 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 391 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 392 char *p = if_indextoname(ifindex, buf); 393 if (p) { 394 return(strlen(p)); 395 } 396 } 397 398 /* last resort */ 399 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 400 if (n < 0 || (size_t)n >= bufsiz) 401 return -1; 402 else 403 return n; 404 } 405 #endif /* INET6 */ 406 407 /* 408 * getnameinfo_link(): 409 * Format a link-layer address into a printable format, paying attention to 410 * the interface type. 411 */ 412 /* ARGSUSED */ 413 static int 414 getnameinfo_link(const struct afd *afd, 415 const struct sockaddr *sa, socklen_t salen, 416 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 417 { 418 const struct sockaddr_dl *sdl = 419 (const struct sockaddr_dl *)(const void *)sa; 420 const struct fw_hwaddr *iha; 421 int n; 422 423 if (serv != NULL && servlen > 0) 424 *serv = '\0'; 425 426 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 427 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 428 if (n >= hostlen) { 429 *host = '\0'; 430 return (EAI_MEMORY); 431 } 432 return (0); 433 } 434 435 if (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0) { 436 n = sdl->sdl_nlen; 437 if (n >= hostlen) { 438 *host = '\0'; 439 return (EAI_MEMORY); 440 } 441 memcpy(host, sdl->sdl_data, sdl->sdl_nlen); 442 host[n] = '\0'; 443 return (0); 444 } 445 446 switch (sdl->sdl_type) { 447 case IFT_IEEE1394: 448 if (sdl->sdl_alen < sizeof(iha->sender_unique_ID_hi) + 449 sizeof(iha->sender_unique_ID_lo)) 450 return EAI_FAMILY; 451 iha = (const struct fw_hwaddr *)(const void *)LLADDR(sdl); 452 return hexname((const u_int8_t *)&iha->sender_unique_ID_hi, 453 sizeof(iha->sender_unique_ID_hi) + 454 sizeof(iha->sender_unique_ID_lo), 455 host, hostlen); 456 /* 457 * The following have zero-length addresses. 458 * IFT_ATM (net/if_atmsubr.c) 459 * IFT_GIF (net/if_gif.c) 460 * IFT_LOOP (net/if_loop.c) 461 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) 462 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 463 * IFT_STF (net/if_stf.c) 464 * IFT_L2VLAN (net/if_vlan.c) 465 * IFT_BRIDGE (net/if_bridge.h> 466 */ 467 /* 468 * The following use IPv4 addresses as link-layer addresses: 469 * IFT_OTHER (net/if_gre.c) 470 * IFT_OTHER (netinet/ip_ipip.c) 471 */ 472 /* default below is believed correct for all these. */ 473 case IFT_ARCNET: 474 case IFT_ETHER: 475 case IFT_FDDI: 476 case IFT_HIPPI: 477 case IFT_ISO88025: 478 default: 479 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 480 host, hostlen); 481 } 482 } 483 484 static int 485 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen) 486 { 487 int i, n; 488 char *outp = host; 489 490 *outp = '\0'; 491 for (i = 0; i < len; i++) { 492 n = snprintf(outp, hostlen, "%s%02x", 493 i ? ":" : "", cp[i]); 494 if (n < 0 || n >= hostlen) { 495 *host = '\0'; 496 return EAI_MEMORY; 497 } 498 outp += n; 499 hostlen -= n; 500 } 501 return 0; 502 } 503 504 /* 505 * getnameinfo_un(): 506 * Format a UNIX IPC domain address (pathname). 507 */ 508 /* ARGSUSED */ 509 static int 510 getnameinfo_un(const struct afd *afd, 511 const struct sockaddr *sa, socklen_t salen, 512 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 513 { 514 size_t pathlen; 515 516 if (serv != NULL && servlen > 0) 517 *serv = '\0'; 518 if (host != NULL && hostlen > 0) { 519 pathlen = sa->sa_len - afd->a_off; 520 521 if (pathlen + 1 > hostlen) { 522 *host = '\0'; 523 return (EAI_MEMORY); 524 } 525 strlcpy(host, (const char *)sa + afd->a_off, pathlen + 1); 526 } 527 528 return (0); 529 } 530