1/* $NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach 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 1.43 2006/02/17 15:58:26 ginsbach Exp $"); 51#endif /* LIBC_SCCS and not lint */ 52 53#include <sys/types.h> 54#include <sys/socket.h> 55#include <net/if.h> 56#include <net/if_dl.h> 57#include <net/if_ieee1394.h> 58#include <net/if_types.h> 59#include <netinet/in.h> 60#include <arpa/inet.h> 61#include "arpa_nameser.h" 62#include <assert.h> 63#include <limits.h> 64#include <netdb.h> 65#ifdef ANDROID_CHANGES 66#include "resolv_private.h" 67#include <sys/system_properties.h> 68#include <stdlib.h> 69#include <unistd.h> 70#include <sys/un.h> 71#include <errno.h> 72#else 73#include <resolv.h> 74#endif 75#include <stddef.h> 76#include <string.h> 77 78static const struct afd { 79 int a_af; 80 socklen_t a_addrlen; 81 socklen_t a_socklen; 82 int a_off; 83} afdl [] = { 84#ifdef INET6 85 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 86 offsetof(struct sockaddr_in6, sin6_addr)}, 87#endif 88 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 89 offsetof(struct sockaddr_in, sin_addr)}, 90 {0, 0, 0, 0}, 91}; 92 93struct sockinet { 94 u_char si_len; 95 u_char si_family; 96 u_short si_port; 97}; 98 99static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *, 100 socklen_t, char *, socklen_t, int)); 101#ifdef INET6 102static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *, 103 socklen_t, int)); 104static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, 105 int)); 106#endif 107static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *, 108 socklen_t, char *, socklen_t, int)); 109static int hexname __P((const u_int8_t *, size_t, char *, socklen_t)); 110 111/* 112 * Top-level getnameinfo() code. Look at the address family, and pick an 113 * appropriate function to call. 114 */ 115int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags) 116{ 117 switch (sa->sa_family) { 118 case AF_INET: 119 case AF_INET6: 120 return getnameinfo_inet(sa, salen, host, hostlen, 121 serv, servlen, flags); 122#if 0 123 case AF_LINK: 124 return getnameinfo_link(sa, salen, host, hostlen, 125 serv, servlen, flags); 126#endif 127 default: 128 return EAI_FAMILY; 129 } 130} 131 132#ifdef ANDROID_CHANGES 133/* On success length of the host name is returned. A return 134 * value of 0 means there's no host name associated with 135 * the address. On failure -1 is returned in which case 136 * normal execution flow shall continue. */ 137static int 138android_gethostbyaddr_proxy(struct hostent* hp, const void *addr, socklen_t addrLen, int addrFamily) { 139 140 int sock; 141 const int one = 1; 142 struct sockaddr_un proxy_addr; 143 const char* cache_mode = getenv("ANDROID_DNS_MODE"); 144 FILE* proxy = NULL; 145 int result = -1; 146 147 if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { 148 // Don't use the proxy in local mode. This is used by the 149 // proxy itself. 150 return -1; 151 } 152 153 // Temporary cautious hack to disable the DNS proxy for processes 154 // requesting special treatment. Ideally the DNS proxy should 155 // accomodate these apps, though. 156 char propname[PROP_NAME_MAX]; 157 char propvalue[PROP_VALUE_MAX]; 158 snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); 159 if (__system_property_get(propname, propvalue) > 0) { 160 return -1; 161 } 162 // create socket 163 sock = socket(AF_UNIX, SOCK_STREAM, 0); 164 if (sock < 0) { 165 return -1; 166 } 167 168 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); 169 memset(&proxy_addr, 0, sizeof(proxy_addr)); 170 proxy_addr.sun_family = AF_UNIX; 171 strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", 172 sizeof(proxy_addr.sun_path)); 173 if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) (void*) &proxy_addr, 174 sizeof(proxy_addr))) != 0) { 175 close(sock); 176 return -1; 177 } 178 179 // send request to DnsProxyListener 180 proxy = fdopen(sock,"r+"); 181 if (proxy == NULL) { 182 goto exit; 183 } 184 185 char buf[INET6_ADDRSTRLEN]; // big enough for IPv4 and IPv6 186 const char* addrStr = inet_ntop(addrFamily, addr, &buf, sizeof(buf)); 187 if (addrStr == NULL) { 188 goto exit; 189 } 190 if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) { 191 goto exit; 192 } 193 194 // literal NULL byte at end, required by FrameworkListener 195 if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { 196 goto exit; 197 } 198 199 result = 0; 200 uint32_t name_len; 201 if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) { 202 goto exit; 203 } 204 205 name_len = ntohl(name_len); 206 if (name_len <= 0) { 207 goto exit; 208 } 209 210 if (fread(hp->h_name, name_len, 1, proxy) != 1) { 211 goto exit; 212 } 213 214 result = name_len; 215 216 exit: 217 if (proxy != NULL) { 218 fclose(proxy); 219 } 220 221 return result; 222} 223#endif 224/* 225 * getnameinfo_inet(): 226 * Format an IPv4 or IPv6 sockaddr into a printable string. 227 */ 228static int 229getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags) 230 const struct sockaddr *sa; 231 socklen_t salen; 232 char *host; 233 socklen_t hostlen; 234 char *serv; 235 socklen_t servlen; 236 int flags; 237{ 238 const struct afd *afd; 239 struct servent *sp; 240 struct hostent *hp; 241 u_short port; 242 int family, i; 243 const char *addr; 244 u_int32_t v4a; 245 char numserv[512]; 246 char numaddr[512]; 247 248 /* sa is checked below */ 249 /* host may be NULL */ 250 /* serv may be NULL */ 251 252 if (sa == NULL) 253 return EAI_FAIL; 254 255#ifdef BSD4_4 256 if (sa->sa_len != salen) 257 return EAI_FAIL; 258#endif 259 260 family = sa->sa_family; 261 for (i = 0; afdl[i].a_af; i++) 262 if (afdl[i].a_af == family) { 263 afd = &afdl[i]; 264 goto found; 265 } 266 return EAI_FAMILY; 267 268 found: 269 if (salen != afd->a_socklen) 270 return EAI_FAIL; 271 272 /* network byte order */ 273 port = ((const struct sockinet *)(const void *)sa)->si_port; 274 addr = (const char *)(const void *)sa + afd->a_off; 275 276 if (serv == NULL || servlen == 0) { 277 /* 278 * do nothing in this case. 279 * in case you are wondering if "&&" is more correct than 280 * "||" here: rfc2553bis-03 says that serv == NULL OR 281 * servlen == 0 means that the caller does not want the result. 282 */ 283 } else { 284 if (flags & NI_NUMERICSERV) 285 sp = NULL; 286 else { 287 sp = getservbyport(port, 288 (flags & NI_DGRAM) ? "udp" : "tcp"); 289 } 290 if (sp) { 291 if (strlen(sp->s_name) + 1 > (size_t)servlen) 292 return EAI_MEMORY; 293 strlcpy(serv, sp->s_name, servlen); 294 } else { 295 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 296 if (strlen(numserv) + 1 > (size_t)servlen) 297 return EAI_MEMORY; 298 strlcpy(serv, numserv, servlen); 299 } 300 } 301 302 switch (sa->sa_family) { 303 case AF_INET: 304 v4a = (u_int32_t) 305 ntohl(((const struct sockaddr_in *) 306 (const void *)sa)->sin_addr.s_addr); 307 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 308 flags |= NI_NUMERICHOST; 309 v4a >>= IN_CLASSA_NSHIFT; 310 if (v4a == 0) 311 flags |= NI_NUMERICHOST; 312 break; 313#ifdef INET6 314 case AF_INET6: 315 { 316 const struct sockaddr_in6 *sin6; 317 sin6 = (const struct sockaddr_in6 *)(const void *)sa; 318 switch (sin6->sin6_addr.s6_addr[0]) { 319 case 0x00: 320 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 321 ; 322 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 323 ; 324 else 325 flags |= NI_NUMERICHOST; 326 break; 327 default: 328 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 329 flags |= NI_NUMERICHOST; 330 } 331 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 332 flags |= NI_NUMERICHOST; 333 break; 334 } 335 } 336 break; 337#endif 338 } 339 if (host == NULL || hostlen == 0) { 340 /* 341 * do nothing in this case. 342 * in case you are wondering if "&&" is more correct than 343 * "||" here: rfc2553bis-03 says that host == NULL or 344 * hostlen == 0 means that the caller does not want the result. 345 */ 346 } else if (flags & NI_NUMERICHOST) { 347 size_t numaddrlen; 348 349 /* NUMERICHOST and NAMEREQD conflicts with each other */ 350 if (flags & NI_NAMEREQD) 351 return EAI_NONAME; 352 353 switch(afd->a_af) { 354#ifdef INET6 355 case AF_INET6: 356 { 357 int error; 358 359 if ((error = ip6_parsenumeric(sa, addr, host, 360 hostlen, flags)) != 0) 361 return(error); 362 break; 363 } 364#endif 365 default: 366 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 367 == NULL) 368 return EAI_SYSTEM; 369 numaddrlen = strlen(numaddr); 370 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 371 return EAI_MEMORY; 372 strlcpy(host, numaddr, hostlen); 373 break; 374 } 375 } else { 376#ifdef ANDROID_CHANGES 377 struct hostent android_proxy_hostent; 378 char android_proxy_buf[MAXDNAME]; 379 android_proxy_hostent.h_name = android_proxy_buf; 380 381 int hostnamelen = android_gethostbyaddr_proxy(&android_proxy_hostent, 382 addr, afd->a_addrlen, afd->a_af); 383 if (hostnamelen >= 0) { 384 hp = (hostnamelen > 0) ? &android_proxy_hostent : NULL; 385 } else { 386 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); 387 } 388#else 389 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); 390#endif 391 392 if (hp) { 393#if 0 394 /* 395 * commented out, since "for local host" is not 396 * implemented here - see RFC2553 p30 397 */ 398 if (flags & NI_NOFQDN) { 399 char *p; 400 p = strchr(hp->h_name, '.'); 401 if (p) 402 *p = '\0'; 403 } 404#endif 405 if (strlen(hp->h_name) + 1 > (size_t)hostlen) { 406 return EAI_MEMORY; 407 } 408 strlcpy(host, hp->h_name, hostlen); 409 } else { 410 if (flags & NI_NAMEREQD) 411 return EAI_NONAME; 412 switch(afd->a_af) { 413#ifdef INET6 414 case AF_INET6: 415 { 416 int error; 417 418 if ((error = ip6_parsenumeric(sa, addr, host, 419 hostlen, 420 flags)) != 0) 421 return(error); 422 break; 423 } 424#endif 425 default: 426 if (inet_ntop(afd->a_af, addr, host, 427 hostlen) == NULL) 428 return EAI_SYSTEM; 429 break; 430 } 431 } 432 } 433 return(0); 434} 435 436#ifdef INET6 437static int 438ip6_parsenumeric(sa, addr, host, hostlen, flags) 439 const struct sockaddr *sa; 440 const char *addr; 441 char *host; 442 socklen_t hostlen; 443 int flags; 444{ 445 size_t numaddrlen; 446 char numaddr[512]; 447 448 assert(sa != NULL); 449 assert(addr != NULL); 450 assert(host != NULL); 451 452 if (hostlen < 0) 453 return EAI_OVERFLOW; 454 455 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 456 return EAI_SYSTEM; 457 458 numaddrlen = strlen(numaddr); 459 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 460 return EAI_OVERFLOW; 461 strlcpy(host, numaddr, hostlen); 462 463 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { 464 char zonebuf[MAXHOSTNAMELEN]; 465 int zonelen; 466 467 zonelen = ip6_sa2str( 468 (const struct sockaddr_in6 *)(const void *)sa, 469 zonebuf, sizeof(zonebuf), flags); 470 if (zonelen < 0) 471 return EAI_OVERFLOW; 472 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) 473 return EAI_OVERFLOW; 474 /* construct <numeric-addr><delim><zoneid> */ 475 memcpy(host + numaddrlen + 1, zonebuf, 476 (size_t)zonelen); 477 host[numaddrlen] = SCOPE_DELIMITER; 478 host[numaddrlen + 1 + zonelen] = '\0'; 479 } 480 481 return 0; 482} 483 484/* ARGSUSED */ 485static int 486ip6_sa2str(sa6, buf, bufsiz, flags) 487 const struct sockaddr_in6 *sa6; 488 char *buf; 489 size_t bufsiz; 490 int flags; 491{ 492 unsigned int ifindex; 493 const struct in6_addr *a6; 494 int n; 495 496 assert(sa6 != NULL); 497 assert(buf != NULL); 498 499 ifindex = (unsigned int)sa6->sin6_scope_id; 500 a6 = &sa6->sin6_addr; 501 502#ifdef NI_NUMERICSCOPE 503 if ((flags & NI_NUMERICSCOPE) != 0) { 504 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 505 if (n < 0 || n >= bufsiz) 506 return -1; 507 else 508 return n; 509 } 510#endif 511 512 /* if_indextoname() does not take buffer size. not a good api... */ 513 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && 514 bufsiz >= IF_NAMESIZE) { 515 char *p = if_indextoname(ifindex, buf); 516 if (p) { 517 return(strlen(p)); 518 } 519 } 520 521 /* last resort */ 522 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 523 if (n < 0 || (size_t) n >= bufsiz) 524 return -1; 525 else 526 return n; 527} 528#endif /* INET6 */ 529 530 531/* 532 * getnameinfo_link(): 533 * Format a link-layer address into a printable format, paying attention to 534 * the interface type. 535 */ 536/* ARGSUSED */ 537static int 538getnameinfo_link(const struct sockaddr *sa, socklen_t salen, 539 char *host, socklen_t hostlen, char *serv, socklen_t servlen, 540 int flags) 541{ 542 const struct sockaddr_dl *sdl = 543 (const struct sockaddr_dl *)(const void *)sa; 544 const struct ieee1394_hwaddr *iha; 545 int n; 546 547 if (serv != NULL && servlen > 0) 548 *serv = '\0'; 549 550 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 551 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index); 552 if (n < 0 || (socklen_t) n > hostlen) { 553 *host = '\0'; 554 return EAI_MEMORY; 555 } 556 return 0; 557 } 558 559 switch (sdl->sdl_type) { 560#ifdef IFT_ECONET 561 case IFT_ECONET: 562 if (sdl->sdl_alen < 2) 563 return EAI_FAMILY; 564 if (CLLADDR(sdl)[1] == 0) 565 n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]); 566 else 567 n = snprintf(host, hostlen, "%u.%u", 568 CLLADDR(sdl)[1], CLLADDR(sdl)[0]); 569 if (n < 0 || (socklen_t) n >= hostlen) { 570 *host = '\0'; 571 return EAI_MEMORY; 572 } else 573 return 0; 574#endif 575 case IFT_IEEE1394: 576 if (sdl->sdl_alen < sizeof(iha->iha_uid)) 577 return EAI_FAMILY; 578 iha = 579 (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl); 580 return hexname(iha->iha_uid, sizeof(iha->iha_uid), 581 host, hostlen); 582 /* 583 * The following have zero-length addresses. 584 * IFT_ATM (net/if_atmsubr.c) 585 * IFT_FAITH (net/if_faith.c) 586 * IFT_GIF (net/if_gif.c) 587 * IFT_LOOP (net/if_loop.c) 588 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) 589 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 590 * IFT_STF (net/if_stf.c) 591 * IFT_L2VLAN (net/if_vlan.c) 592 * IFT_PROPVIRTUAL (net/if_bridge.h> 593 */ 594 /* 595 * The following use IPv4 addresses as link-layer addresses: 596 * IFT_OTHER (net/if_gre.c) 597 */ 598 case IFT_ARCNET: /* default below is believed correct for all these. */ 599 case IFT_ETHER: 600 case IFT_FDDI: 601 case IFT_HIPPI: 602 case IFT_ISO88025: 603 default: 604 return hexname((const u_int8_t *)CLLADDR(sdl), 605 (size_t)sdl->sdl_alen, host, hostlen); 606 } 607} 608 609static int 610hexname(cp, len, host, hostlen) 611 const u_int8_t *cp; 612 char *host; 613 size_t len; 614 socklen_t hostlen; 615{ 616 int n; 617 size_t i; 618 char *outp = host; 619 620 *outp = '\0'; 621 for (i = 0; i < len; i++) { 622 n = snprintf(outp, hostlen, "%s%02x", 623 i ? ":" : "", cp[i]); 624 if (n < 0 || (socklen_t) n >= hostlen) { 625 *host = '\0'; 626 return EAI_MEMORY; 627 } 628 outp += n; 629 hostlen -= n; 630 } 631 return 0; 632} 633