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#if defined(ANDROID_CHANGES) && defined(AF_LINK) 57#include <net/if_dl.h> 58#endif 59#include <net/if_ieee1394.h> 60#include <net/if_types.h> 61#include <netinet/in.h> 62#include <arpa/inet.h> 63#include "arpa_nameser.h" 64#include <assert.h> 65#include <limits.h> 66#include <netdb.h> 67#ifdef ANDROID_CHANGES 68#include "resolv_private.h" 69#include <sys/system_properties.h> 70#include <stdlib.h> 71#include <unistd.h> 72#include <sys/un.h> 73#include <errno.h> 74#else 75#include <resolv.h> 76#endif 77#include <stddef.h> 78#include <string.h> 79 80static const struct afd { 81 int a_af; 82 socklen_t a_addrlen; 83 socklen_t a_socklen; 84 int a_off; 85} afdl [] = { 86#ifdef INET6 87 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 88 offsetof(struct sockaddr_in6, sin6_addr)}, 89#endif 90 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 91 offsetof(struct sockaddr_in, sin_addr)}, 92 {0, 0, 0, 0}, 93}; 94 95struct sockinet { 96 u_char si_len; 97 u_char si_family; 98 u_short si_port; 99}; 100 101static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *, 102 socklen_t, char *, socklen_t, int)); 103#ifdef INET6 104static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *, 105 socklen_t, int)); 106static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, 107 int)); 108#endif 109#if defined(ANDROID_CHANGES) && defined(AF_LINK) 110static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *, 111 socklen_t, char *, socklen_t, int)); 112#endif 113static int hexname __P((const u_int8_t *, size_t, char *, socklen_t)); 114 115// This should be synchronized to ResponseCode.h 116static const int DnsProxyQueryResult = 222; 117 118 119/* 120 * Top-level getnameinfo() code. Look at the address family, and pick an 121 * appropriate function to call. 122 */ 123int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags) 124{ 125 switch (sa->sa_family) { 126 case AF_INET: 127 case AF_INET6: 128 return getnameinfo_inet(sa, salen, host, hostlen, 129 serv, servlen, flags); 130#if defined(ANDROID_CHANGES) && defined(AF_LINK) 131 case AF_LINK: 132 return getnameinfo_link(sa, salen, host, hostlen, 133 serv, servlen, flags); 134#endif 135 default: 136 return EAI_FAMILY; 137 } 138} 139 140#ifdef ANDROID_CHANGES 141/* On success length of the host name is returned. A return 142 * value of 0 means there's no host name associated with 143 * the address. On failure -1 is returned in which case 144 * normal execution flow shall continue. */ 145static int 146android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily) { 147 148 int sock; 149 const int one = 1; 150 struct sockaddr_un proxy_addr; 151 const char* cache_mode = getenv("ANDROID_DNS_MODE"); 152 FILE* proxy = NULL; 153 int result = -1; 154 155 if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { 156 // Don't use the proxy in local mode. This is used by the 157 // proxy itself. 158 return -1; 159 } 160 161 // Temporary cautious hack to disable the DNS proxy for processes 162 // requesting special treatment. Ideally the DNS proxy should 163 // accomodate these apps, though. 164 char propname[PROP_NAME_MAX]; 165 char propvalue[PROP_VALUE_MAX]; 166 snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); 167 if (__system_property_get(propname, propvalue) > 0) { 168 return -1; 169 } 170 // create socket 171 sock = socket(AF_UNIX, SOCK_STREAM, 0); 172 if (sock < 0) { 173 return -1; 174 } 175 176 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); 177 memset(&proxy_addr, 0, sizeof(proxy_addr)); 178 proxy_addr.sun_family = AF_UNIX; 179 strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", 180 sizeof(proxy_addr.sun_path)); 181 if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) (void*) &proxy_addr, 182 sizeof(proxy_addr))) != 0) { 183 close(sock); 184 return -1; 185 } 186 187 // send request to DnsProxyListener 188 proxy = fdopen(sock,"r+"); 189 if (proxy == NULL) { 190 goto exit; 191 } 192 193 char buf[INET6_ADDRSTRLEN]; // big enough for IPv4 and IPv6 194 const char* addrStr = inet_ntop(addrFamily, addr, buf, sizeof(buf)); 195 if (addrStr == NULL) { 196 goto exit; 197 } 198 if (fprintf(proxy, "gethostbyaddr %s %d %d", addrStr, addrLen, addrFamily) < 0) { 199 goto exit; 200 } 201 202 // literal NULL byte at end, required by FrameworkListener 203 if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { 204 goto exit; 205 } 206 207 result = 0; 208 char msg_buf[4]; 209 // read result code for gethostbyaddr 210 if (fread(msg_buf, 1, sizeof(msg_buf), proxy) != sizeof(msg_buf)) { 211 goto exit; 212 } 213 214 int result_code = (int)strtol(msg_buf, NULL, 10); 215 // verify the code itself 216 if (result_code != DnsProxyQueryResult) { 217 goto exit; 218 } 219 220 uint32_t name_len; 221 if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) { 222 goto exit; 223 } 224 225 name_len = ntohl(name_len); 226 if (name_len <= 0 || name_len >= nameBufLen) { 227 goto exit; 228 } 229 230 if (fread(nameBuf, name_len, 1, proxy) != 1) { 231 goto exit; 232 } 233 234 result = name_len; 235 236 exit: 237 if (proxy != NULL) { 238 fclose(proxy); 239 } 240 241 return result; 242} 243#endif 244/* 245 * getnameinfo_inet(): 246 * Format an IPv4 or IPv6 sockaddr into a printable string. 247 */ 248static int 249getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags) 250 const struct sockaddr *sa; 251 socklen_t salen; 252 char *host; 253 socklen_t hostlen; 254 char *serv; 255 socklen_t servlen; 256 int flags; 257{ 258 const struct afd *afd; 259 struct servent *sp; 260 struct hostent *hp; 261 u_short port; 262 int family, i; 263 const char *addr; 264 u_int32_t v4a; 265 char numserv[512]; 266 char numaddr[512]; 267 268 /* sa is checked below */ 269 /* host may be NULL */ 270 /* serv may be NULL */ 271 272 if (sa == NULL) 273 return EAI_FAIL; 274 275#ifdef BSD4_4 276 if (sa->sa_len != salen) 277 return EAI_FAIL; 278#endif 279 280 family = sa->sa_family; 281 for (i = 0; afdl[i].a_af; i++) 282 if (afdl[i].a_af == family) { 283 afd = &afdl[i]; 284 goto found; 285 } 286 return EAI_FAMILY; 287 288 found: 289 if (salen != afd->a_socklen) 290 return EAI_FAIL; 291 292 /* network byte order */ 293 port = ((const struct sockinet *)(const void *)sa)->si_port; 294 addr = (const char *)(const void *)sa + afd->a_off; 295 296 if (serv == NULL || servlen == 0) { 297 /* 298 * do nothing in this case. 299 * in case you are wondering if "&&" is more correct than 300 * "||" here: rfc2553bis-03 says that serv == NULL OR 301 * servlen == 0 means that the caller does not want the result. 302 */ 303 } else { 304 if (flags & NI_NUMERICSERV) 305 sp = NULL; 306 else { 307 sp = getservbyport(port, 308 (flags & NI_DGRAM) ? "udp" : "tcp"); 309 } 310 if (sp) { 311 if (strlen(sp->s_name) + 1 > (size_t)servlen) 312 return EAI_MEMORY; 313 strlcpy(serv, sp->s_name, servlen); 314 } else { 315 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 316 if (strlen(numserv) + 1 > (size_t)servlen) 317 return EAI_MEMORY; 318 strlcpy(serv, numserv, servlen); 319 } 320 } 321 322 switch (sa->sa_family) { 323 case AF_INET: 324 v4a = (u_int32_t) 325 ntohl(((const struct sockaddr_in *) 326 (const void *)sa)->sin_addr.s_addr); 327 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 328 flags |= NI_NUMERICHOST; 329 v4a >>= IN_CLASSA_NSHIFT; 330 if (v4a == 0) 331 flags |= NI_NUMERICHOST; 332 break; 333#ifdef INET6 334 case AF_INET6: 335 { 336 const struct sockaddr_in6 *sin6; 337 sin6 = (const struct sockaddr_in6 *)(const void *)sa; 338 switch (sin6->sin6_addr.s6_addr[0]) { 339 case 0x00: 340 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 341 ; 342 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 343 ; 344 else 345 flags |= NI_NUMERICHOST; 346 break; 347 default: 348 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 349 flags |= NI_NUMERICHOST; 350 } 351 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 352 flags |= NI_NUMERICHOST; 353 break; 354 } 355 } 356 break; 357#endif 358 } 359 if (host == NULL || hostlen == 0) { 360 /* 361 * do nothing in this case. 362 * in case you are wondering if "&&" is more correct than 363 * "||" here: rfc2553bis-03 says that host == NULL or 364 * hostlen == 0 means that the caller does not want the result. 365 */ 366 } else if (flags & NI_NUMERICHOST) { 367 size_t numaddrlen; 368 369 /* NUMERICHOST and NAMEREQD conflicts with each other */ 370 if (flags & NI_NAMEREQD) 371 return EAI_NONAME; 372 373 switch(afd->a_af) { 374#ifdef INET6 375 case AF_INET6: 376 { 377 int error; 378 379 if ((error = ip6_parsenumeric(sa, addr, host, 380 hostlen, flags)) != 0) 381 return(error); 382 break; 383 } 384#endif 385 default: 386 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 387 == NULL) 388 return EAI_SYSTEM; 389 numaddrlen = strlen(numaddr); 390 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 391 return EAI_MEMORY; 392 strlcpy(host, numaddr, hostlen); 393 break; 394 } 395 } else { 396#ifdef ANDROID_CHANGES 397 struct hostent android_proxy_hostent; 398 char android_proxy_buf[MAXDNAME]; 399 400 int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf, 401 MAXDNAME, addr, afd->a_addrlen, afd->a_af); 402 if (hostnamelen > 0) { 403 hp = &android_proxy_hostent; 404 hp->h_name = android_proxy_buf; 405 } else if (!hostnamelen) { 406 hp = NULL; 407 } else { 408 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); 409 } 410#else 411 hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af); 412#endif 413 414 if (hp) { 415#if defined(ANDROID_CHANGES) && defined(AF_LINK) 416 /* 417 * commented out, since "for local host" is not 418 * implemented here - see RFC2553 p30 419 */ 420 if (flags & NI_NOFQDN) { 421 char *p; 422 p = strchr(hp->h_name, '.'); 423 if (p) 424 *p = '\0'; 425 } 426#endif 427 if (strlen(hp->h_name) + 1 > (size_t)hostlen) { 428 return EAI_MEMORY; 429 } 430 strlcpy(host, hp->h_name, hostlen); 431 } else { 432 if (flags & NI_NAMEREQD) 433 return EAI_NONAME; 434 switch(afd->a_af) { 435#ifdef INET6 436 case AF_INET6: 437 { 438 int error; 439 440 if ((error = ip6_parsenumeric(sa, addr, host, 441 hostlen, 442 flags)) != 0) 443 return(error); 444 break; 445 } 446#endif 447 default: 448 if (inet_ntop(afd->a_af, addr, host, 449 hostlen) == NULL) 450 return EAI_SYSTEM; 451 break; 452 } 453 } 454 } 455 return(0); 456} 457 458#ifdef INET6 459static int 460ip6_parsenumeric(sa, addr, host, hostlen, flags) 461 const struct sockaddr *sa; 462 const char *addr; 463 char *host; 464 socklen_t hostlen; 465 int flags; 466{ 467 size_t numaddrlen; 468 char numaddr[512]; 469 470 assert(sa != NULL); 471 assert(addr != NULL); 472 assert(host != NULL); 473 474 if (hostlen < 0) 475 return EAI_OVERFLOW; 476 477 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 478 return EAI_SYSTEM; 479 480 numaddrlen = strlen(numaddr); 481 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 482 return EAI_OVERFLOW; 483 strlcpy(host, numaddr, hostlen); 484 485 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { 486 char zonebuf[MAXHOSTNAMELEN]; 487 int zonelen; 488 489 zonelen = ip6_sa2str( 490 (const struct sockaddr_in6 *)(const void *)sa, 491 zonebuf, sizeof(zonebuf), flags); 492 if (zonelen < 0) 493 return EAI_OVERFLOW; 494 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) 495 return EAI_OVERFLOW; 496 /* construct <numeric-addr><delim><zoneid> */ 497 memcpy(host + numaddrlen + 1, zonebuf, 498 (size_t)zonelen); 499 host[numaddrlen] = SCOPE_DELIMITER; 500 host[numaddrlen + 1 + zonelen] = '\0'; 501 } 502 503 return 0; 504} 505 506/* ARGSUSED */ 507static int 508ip6_sa2str(sa6, buf, bufsiz, flags) 509 const struct sockaddr_in6 *sa6; 510 char *buf; 511 size_t bufsiz; 512 int flags; 513{ 514 unsigned int ifindex; 515 const struct in6_addr *a6; 516 int n; 517 518 assert(sa6 != NULL); 519 assert(buf != NULL); 520 521 ifindex = (unsigned int)sa6->sin6_scope_id; 522 a6 = &sa6->sin6_addr; 523 524#ifdef NI_NUMERICSCOPE 525 if ((flags & NI_NUMERICSCOPE) != 0) { 526 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 527 if (n < 0 || n >= bufsiz) 528 return -1; 529 else 530 return n; 531 } 532#endif 533 534 /* if_indextoname() does not take buffer size. not a good api... */ 535 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && 536 bufsiz >= IF_NAMESIZE) { 537 char *p = if_indextoname(ifindex, buf); 538 if (p) { 539 return(strlen(p)); 540 } 541 } 542 543 /* last resort */ 544 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 545 if (n < 0 || (size_t) n >= bufsiz) 546 return -1; 547 else 548 return n; 549} 550#endif /* INET6 */ 551 552 553#if defined(ANDROID_CHANGES) && defined(AF_LINK) 554/* 555 * getnameinfo_link(): 556 * Format a link-layer address into a printable format, paying attention to 557 * the interface type. 558 */ 559/* ARGSUSED */ 560static int 561getnameinfo_link(const struct sockaddr *sa, socklen_t salen, 562 char *host, socklen_t hostlen, char *serv, socklen_t servlen, 563 int flags) 564{ 565 const struct sockaddr_dl *sdl = 566 (const struct sockaddr_dl *)(const void *)sa; 567 const struct ieee1394_hwaddr *iha; 568 int n; 569 570 if (serv != NULL && servlen > 0) 571 *serv = '\0'; 572 573 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 574 n = snprintf(host, hostlen, "link#%u", sdl->sdl_index); 575 if (n < 0 || (socklen_t) n > hostlen) { 576 *host = '\0'; 577 return EAI_MEMORY; 578 } 579 return 0; 580 } 581 582 switch (sdl->sdl_type) { 583#ifdef IFT_ECONET 584 case IFT_ECONET: 585 if (sdl->sdl_alen < 2) 586 return EAI_FAMILY; 587 if (CLLADDR(sdl)[1] == 0) 588 n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]); 589 else 590 n = snprintf(host, hostlen, "%u.%u", 591 CLLADDR(sdl)[1], CLLADDR(sdl)[0]); 592 if (n < 0 || (socklen_t) n >= hostlen) { 593 *host = '\0'; 594 return EAI_MEMORY; 595 } else 596 return 0; 597#endif 598 case IFT_IEEE1394: 599 if (sdl->sdl_alen < sizeof(iha->iha_uid)) 600 return EAI_FAMILY; 601 iha = 602 (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl); 603 return hexname(iha->iha_uid, sizeof(iha->iha_uid), 604 host, hostlen); 605 /* 606 * The following have zero-length addresses. 607 * IFT_ATM (net/if_atmsubr.c) 608 * IFT_FAITH (net/if_faith.c) 609 * IFT_GIF (net/if_gif.c) 610 * IFT_LOOP (net/if_loop.c) 611 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) 612 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 613 * IFT_STF (net/if_stf.c) 614 * IFT_L2VLAN (net/if_vlan.c) 615 * IFT_PROPVIRTUAL (net/if_bridge.h> 616 */ 617 /* 618 * The following use IPv4 addresses as link-layer addresses: 619 * IFT_OTHER (net/if_gre.c) 620 */ 621 case IFT_ARCNET: /* default below is believed correct for all these. */ 622 case IFT_ETHER: 623 case IFT_FDDI: 624 case IFT_HIPPI: 625 case IFT_ISO88025: 626 default: 627 return hexname((const u_int8_t *)CLLADDR(sdl), 628 (size_t)sdl->sdl_alen, host, hostlen); 629 } 630} 631#endif 632 633static int 634hexname(cp, len, host, hostlen) 635 const u_int8_t *cp; 636 char *host; 637 size_t len; 638 socklen_t hostlen; 639{ 640 int n; 641 size_t i; 642 char *outp = host; 643 644 *outp = '\0'; 645 for (i = 0; i < len; i++) { 646 n = snprintf(outp, hostlen, "%s%02x", 647 i ? ":" : "", cp[i]); 648 if (n < 0 || (socklen_t) n >= hostlen) { 649 *host = '\0'; 650 return EAI_MEMORY; 651 } 652 outp += n; 653 hostlen -= n; 654 } 655 return 0; 656} 657