1 /* $NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos 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 1.53 2012/09/26 23:13:00 christos Exp $"); 51 #endif /* LIBC_SCCS and not lint */ 52 53 #include <sys/types.h> 54 #include <sys/socket.h> 55 #include <sys/un.h> 56 #include <net/if.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 <assert.h> 62 #include <limits.h> 63 #include <netdb.h> 64 #include "arpa_nameser.h" 65 #include "resolv_private.h" 66 #include <sys/system_properties.h> 67 #include <stdlib.h> 68 #include <unistd.h> 69 #include <errno.h> 70 #define MIN(x,y) ((x) < (y) ? (x) : (y)) 71 #include <stddef.h> 72 #include <string.h> 73 74 static const struct afd { 75 int a_af; 76 socklen_t a_addrlen; 77 socklen_t a_socklen; 78 int a_off; 79 } afdl [] = { 80 #ifdef INET6 81 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 82 offsetof(struct sockaddr_in6, sin6_addr)}, 83 #endif 84 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 85 offsetof(struct sockaddr_in, sin_addr)}, 86 {0, 0, 0, 0}, 87 }; 88 89 struct sockinet { 90 u_char si_len; 91 u_char si_family; 92 u_short si_port; 93 }; 94 95 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 96 socklen_t, char *, socklen_t, int, const char*, int); 97 #ifdef INET6 98 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 99 socklen_t, int); 100 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 101 #endif 102 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *, 103 socklen_t, char *, socklen_t, int); 104 105 /* 106 * Top-level getnameinfo() code. Look at the address family, and pick an 107 * appropriate function to call. 108 */ 109 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags) 110 { 111 return android_getnameinfoforiface(sa, salen, host, hostlen, serv, servlen, flags, NULL, 0); 112 } 113 114 int android_getnameinfoforiface(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, char* serv, size_t servlen, int flags, const char* iface, int mark) 115 { 116 switch (sa->sa_family) { 117 case AF_INET: 118 case AF_INET6: 119 return getnameinfo_inet(sa, salen, host, hostlen, 120 serv, servlen, flags, iface, mark); 121 case AF_LOCAL: 122 return getnameinfo_local(sa, salen, host, hostlen, 123 serv, servlen, flags); 124 default: 125 return EAI_FAMILY; 126 } 127 } 128 129 /* 130 * getnameinfo_local(): 131 * Format an local address into a printable format. 132 */ 133 /* ARGSUSED */ 134 static int 135 getnameinfo_local(const struct sockaddr *sa, socklen_t salen, 136 char *host, socklen_t hostlen, char *serv, socklen_t servlen, 137 int flags __attribute__((unused))) 138 { 139 const struct sockaddr_un *sun = 140 (const struct sockaddr_un *)(const void *)sa; 141 142 if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) { 143 return EAI_FAMILY; 144 } 145 146 if (serv != NULL && servlen > 0) 147 serv[0] = '\0'; 148 149 if (host && hostlen > 0) 150 strlcpy(host, sun->sun_path, 151 MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen)); 152 153 return 0; 154 } 155 156 /* On success length of the host name is returned. A return 157 * value of 0 means there's no host name associated with 158 * the address. On failure -1 is returned in which case 159 * normal execution flow shall continue. */ 160 static int 161 android_gethostbyaddr_proxy(char* nameBuf, size_t nameBufLen, const void *addr, socklen_t addrLen, int addrFamily, const char* iface, int mark) 162 { 163 struct hostent *hostResult = 164 android_gethostbyaddrforiface_proxy(addr, addrLen, addrFamily, iface, mark); 165 166 if (hostResult == NULL) return 0; 167 168 int lengthResult = strlen(hostResult->h_name); 169 170 if (nameBuf) strncpy(nameBuf, hostResult->h_name, nameBufLen); 171 return lengthResult; 172 } 173 174 /* 175 * getnameinfo_inet(): 176 * Format an IPv4 or IPv6 sockaddr into a printable string. 177 */ 178 static int 179 getnameinfo_inet(const struct sockaddr* sa, socklen_t salen, 180 char *host, socklen_t hostlen, 181 char *serv, socklen_t servlen, 182 int flags, const char* iface, int mark) 183 { 184 const struct afd *afd; 185 struct servent *sp; 186 struct hostent *hp; 187 u_short port; 188 int family, i; 189 const char *addr; 190 uint32_t v4a; 191 char numserv[512]; 192 char numaddr[512]; 193 194 /* sa is checked below */ 195 /* host may be NULL */ 196 /* serv may be NULL */ 197 198 if (sa == NULL) 199 return EAI_FAIL; 200 201 family = sa->sa_family; 202 for (i = 0; afdl[i].a_af; i++) 203 if (afdl[i].a_af == family) { 204 afd = &afdl[i]; 205 goto found; 206 } 207 return EAI_FAMILY; 208 209 found: 210 // http://b/1889275: callers should be allowed to provide too much 211 // space, but not too little. 212 if (salen < afd->a_socklen) { 213 return EAI_FAMILY; 214 } 215 216 /* network byte order */ 217 port = ((const struct sockinet *)(const void *)sa)->si_port; 218 addr = (const char *)(const void *)sa + afd->a_off; 219 220 if (serv == NULL || servlen == 0) { 221 /* 222 * do nothing in this case. 223 * in case you are wondering if "&&" is more correct than 224 * "||" here: rfc2553bis-03 says that serv == NULL OR 225 * servlen == 0 means that the caller does not want the result. 226 */ 227 } else { 228 if (flags & NI_NUMERICSERV) 229 sp = NULL; 230 else { 231 sp = getservbyport(port, 232 (flags & NI_DGRAM) ? "udp" : "tcp"); 233 } 234 if (sp) { 235 if (strlen(sp->s_name) + 1 > (size_t)servlen) 236 return EAI_MEMORY; 237 strlcpy(serv, sp->s_name, servlen); 238 } else { 239 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 240 if (strlen(numserv) + 1 > (size_t)servlen) 241 return EAI_MEMORY; 242 strlcpy(serv, numserv, servlen); 243 } 244 } 245 246 switch (sa->sa_family) { 247 case AF_INET: 248 v4a = (uint32_t) 249 ntohl(((const struct sockaddr_in *) 250 (const void *)sa)->sin_addr.s_addr); 251 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 252 flags |= NI_NUMERICHOST; 253 v4a >>= IN_CLASSA_NSHIFT; 254 if (v4a == 0) 255 flags |= NI_NUMERICHOST; 256 break; 257 #ifdef INET6 258 case AF_INET6: 259 { 260 const struct sockaddr_in6 *sin6; 261 sin6 = (const struct sockaddr_in6 *)(const void *)sa; 262 switch (sin6->sin6_addr.s6_addr[0]) { 263 case 0x00: 264 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 265 ; 266 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 267 ; 268 else 269 flags |= NI_NUMERICHOST; 270 break; 271 default: 272 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 273 flags |= NI_NUMERICHOST; 274 } 275 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 276 flags |= NI_NUMERICHOST; 277 break; 278 } 279 } 280 break; 281 #endif 282 } 283 if (host == NULL || hostlen == 0) { 284 /* 285 * do nothing in this case. 286 * in case you are wondering if "&&" is more correct than 287 * "||" here: rfc2553bis-03 says that host == NULL or 288 * hostlen == 0 means that the caller does not want the result. 289 */ 290 } else if (flags & NI_NUMERICHOST) { 291 size_t numaddrlen; 292 293 /* NUMERICHOST and NAMEREQD conflicts with each other */ 294 if (flags & NI_NAMEREQD) 295 return EAI_NONAME; 296 297 switch(afd->a_af) { 298 #ifdef INET6 299 case AF_INET6: 300 { 301 int error; 302 303 if ((error = ip6_parsenumeric(sa, addr, host, 304 hostlen, flags)) != 0) 305 return(error); 306 break; 307 } 308 #endif 309 default: 310 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 311 == NULL) 312 return EAI_SYSTEM; 313 numaddrlen = strlen(numaddr); 314 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 315 return EAI_MEMORY; 316 strlcpy(host, numaddr, hostlen); 317 break; 318 } 319 } else { 320 struct hostent android_proxy_hostent; 321 char android_proxy_buf[MAXDNAME]; 322 323 int hostnamelen = android_gethostbyaddr_proxy(android_proxy_buf, 324 MAXDNAME, addr, afd->a_addrlen, afd->a_af, iface, mark); 325 if (hostnamelen > 0) { 326 hp = &android_proxy_hostent; 327 hp->h_name = android_proxy_buf; 328 } else if (!hostnamelen) { 329 hp = NULL; 330 } else { 331 hp = android_gethostbyaddrforiface(addr, afd->a_addrlen, afd->a_af, 332 iface, mark); 333 } 334 335 if (hp) { 336 #if 0 337 /* 338 * commented out, since "for local host" is not 339 * implemented here - see RFC2553 p30 340 */ 341 if (flags & NI_NOFQDN) { 342 char *p; 343 p = strchr(hp->h_name, '.'); 344 if (p) 345 *p = '\0'; 346 } 347 #endif 348 if (strlen(hp->h_name) + 1 > (size_t)hostlen) { 349 return EAI_MEMORY; 350 } 351 strlcpy(host, hp->h_name, hostlen); 352 } else { 353 if (flags & NI_NAMEREQD) 354 return EAI_NONAME; 355 switch(afd->a_af) { 356 #ifdef INET6 357 case AF_INET6: 358 { 359 int error; 360 361 if ((error = ip6_parsenumeric(sa, addr, host, 362 hostlen, 363 flags)) != 0) 364 return(error); 365 break; 366 } 367 #endif 368 default: 369 if (inet_ntop(afd->a_af, addr, host, 370 hostlen) == NULL) 371 return EAI_SYSTEM; 372 break; 373 } 374 } 375 } 376 return(0); 377 } 378 379 #ifdef INET6 380 static int 381 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 382 socklen_t hostlen, int flags) 383 { 384 size_t numaddrlen; 385 char numaddr[512]; 386 387 assert(sa != NULL); 388 assert(addr != NULL); 389 assert(host != NULL); 390 391 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 392 return EAI_SYSTEM; 393 394 numaddrlen = strlen(numaddr); 395 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 396 return EAI_OVERFLOW; 397 strlcpy(host, numaddr, hostlen); 398 399 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { 400 char zonebuf[MAXHOSTNAMELEN]; 401 int zonelen; 402 403 zonelen = ip6_sa2str( 404 (const struct sockaddr_in6 *)(const void *)sa, 405 zonebuf, sizeof(zonebuf), flags); 406 if (zonelen < 0) 407 return EAI_OVERFLOW; 408 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) 409 return EAI_OVERFLOW; 410 /* construct <numeric-addr><delim><zoneid> */ 411 memcpy(host + numaddrlen + 1, zonebuf, 412 (size_t)zonelen); 413 host[numaddrlen] = SCOPE_DELIMITER; 414 host[numaddrlen + 1 + zonelen] = '\0'; 415 } 416 417 return 0; 418 } 419 420 /* ARGSUSED */ 421 static int 422 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 423 { 424 unsigned int ifindex; 425 const struct in6_addr *a6; 426 int n; 427 428 assert(sa6 != NULL); 429 assert(buf != NULL); 430 431 ifindex = (unsigned int)sa6->sin6_scope_id; 432 a6 = &sa6->sin6_addr; 433 434 #ifdef NI_NUMERICSCOPE 435 if ((flags & NI_NUMERICSCOPE) != 0) { 436 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 437 if (n < 0 || n >= bufsiz) 438 return -1; 439 else 440 return n; 441 } 442 #endif 443 444 /* if_indextoname() does not take buffer size. not a good api... */ 445 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && 446 bufsiz >= IF_NAMESIZE) { 447 char *p = if_indextoname(ifindex, buf); 448 if (p) { 449 return(strlen(p)); 450 } 451 } 452 453 /* last resort */ 454 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 455 if (n < 0 || (size_t) n >= bufsiz) 456 return -1; 457 else 458 return n; 459 } 460 #endif /* INET6 */ 461
