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 <net/if.h> 53 #include <net/if_dl.h> 54 #include <net/if_types.h> 55 #include <netinet/in.h> 56 #include <arpa/inet.h> 57 #include <arpa/nameser.h> 58 #include <netdb.h> 59 #include <resolv.h> 60 #include <string.h> 61 #include <stddef.h> 62 #include <errno.h> 63 64 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 65 size_t, char *, size_t, int); 66 #ifdef INET6 67 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 68 size_t, int); 69 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 70 #endif 71 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *, 72 size_t, char *, size_t, int); 73 static int hexname(const u_int8_t *, size_t, char *, size_t); 74 75 int 76 getnameinfo(const struct sockaddr *sa, socklen_t salen, 77 char *host, size_t hostlen, char *serv, size_t servlen, 78 int flags) 79 { 80 81 switch (sa->sa_family) { 82 case AF_INET: 83 #ifdef INET6 84 case AF_INET6: 85 #endif 86 return getnameinfo_inet(sa, salen, host, hostlen, serv, 87 servlen, flags); 88 case AF_LINK: 89 return getnameinfo_link(sa, salen, host, hostlen, serv, 90 servlen, flags); 91 default: 92 return EAI_FAMILY; 93 } 94 } 95 96 static const struct afd { 97 int a_af; 98 size_t a_addrlen; 99 socklen_t a_socklen; 100 int a_off; 101 } afdl [] = { 102 #ifdef INET6 103 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 104 offsetof(struct sockaddr_in6, sin6_addr)}, 105 #endif 106 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 107 offsetof(struct sockaddr_in, sin_addr)}, 108 {0, 0, 0}, 109 }; 110 111 struct sockinet { 112 u_char si_len; 113 u_char si_family; 114 u_short si_port; 115 }; 116 117 static int 118 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen, 119 char *host, size_t hostlen, char *serv, size_t servlen, 120 int flags) 121 { 122 const struct afd *afd; 123 struct servent *sp; 124 struct hostent *hp; 125 u_short port; 126 int family, i; 127 const char *addr; 128 u_int32_t v4a; 129 int h_error; 130 char numserv[512]; 131 char numaddr[512]; 132 133 if (sa == NULL) 134 return EAI_FAIL; 135 136 family = sa->sa_family; 137 for (i = 0; afdl[i].a_af; i++) 138 if (afdl[i].a_af == family) { 139 afd = &afdl[i]; 140 goto found; 141 } 142 return EAI_FAMILY; 143 144 found: 145 if (salen != afd->a_socklen) 146 return EAI_FAIL; 147 148 /* network byte order */ 149 port = ((const struct sockinet *)sa)->si_port; 150 addr = (const char *)sa + afd->a_off; 151 152 if (serv == NULL || servlen == 0) { 153 /* 154 * do nothing in this case. 155 * in case you are wondering if "&&" is more correct than 156 * "||" here: rfc2553bis-03 says that serv == NULL OR 157 * servlen == 0 means that the caller does not want the result. 158 */ 159 } else { 160 if (flags & NI_NUMERICSERV) 161 sp = NULL; 162 else { 163 sp = getservbyport(port, 164 (flags & NI_DGRAM) ? "udp" : "tcp"); 165 } 166 if (sp) { 167 if (strlen(sp->s_name) + 1 > servlen) 168 return EAI_MEMORY; 169 strlcpy(serv, sp->s_name, servlen); 170 } else { 171 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 172 if (strlen(numserv) + 1 > servlen) 173 return EAI_MEMORY; 174 strlcpy(serv, numserv, servlen); 175 } 176 } 177 178 switch (sa->sa_family) { 179 case AF_INET: 180 v4a = (u_int32_t) 181 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 182 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 183 flags |= NI_NUMERICHOST; 184 v4a >>= IN_CLASSA_NSHIFT; 185 if (v4a == 0) 186 flags |= NI_NUMERICHOST; 187 break; 188 #ifdef INET6 189 case AF_INET6: 190 { 191 const struct sockaddr_in6 *sin6; 192 sin6 = (const struct sockaddr_in6 *)sa; 193 switch (sin6->sin6_addr.s6_addr[0]) { 194 case 0x00: 195 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 196 ; 197 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 198 ; 199 else 200 flags |= NI_NUMERICHOST; 201 break; 202 default: 203 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 204 flags |= NI_NUMERICHOST; 205 } 206 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 207 flags |= NI_NUMERICHOST; 208 break; 209 } 210 } 211 break; 212 #endif 213 } 214 if (host == NULL || hostlen == 0) { 215 /* 216 * do nothing in this case. 217 * in case you are wondering if "&&" is more correct than 218 * "||" here: rfc2553bis-03 says that host == NULL or 219 * hostlen == 0 means that the caller does not want the result. 220 */ 221 } else if (flags & NI_NUMERICHOST) { 222 size_t numaddrlen; 223 224 /* NUMERICHOST and NAMEREQD conflicts with each other */ 225 if (flags & NI_NAMEREQD) 226 return EAI_NONAME; 227 228 switch(afd->a_af) { 229 #ifdef INET6 230 case AF_INET6: 231 { 232 int error; 233 234 if ((error = ip6_parsenumeric(sa, addr, host, 235 hostlen, flags)) != 0) 236 return(error); 237 break; 238 } 239 #endif 240 default: 241 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 242 == NULL) 243 return EAI_SYSTEM; 244 numaddrlen = strlen(numaddr); 245 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 246 return EAI_MEMORY; 247 strlcpy(host, numaddr, hostlen); 248 break; 249 } 250 } else { 251 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 252 253 if (hp) { 254 #if 0 255 /* 256 * commented out, since "for local host" is not 257 * implemented here - see RFC2553 p30 258 */ 259 if (flags & NI_NOFQDN) { 260 char *p; 261 p = strchr(hp->h_name, '.'); 262 if (p) 263 *p = '\0'; 264 } 265 #endif 266 if (strlen(hp->h_name) + 1 > hostlen) { 267 freehostent(hp); 268 return EAI_MEMORY; 269 } 270 strlcpy(host, hp->h_name, hostlen); 271 freehostent(hp); 272 } else { 273 if (flags & NI_NAMEREQD) 274 return EAI_NONAME; 275 switch(afd->a_af) { 276 #ifdef INET6 277 case AF_INET6: 278 { 279 int error; 280 281 if ((error = ip6_parsenumeric(sa, addr, host, 282 hostlen, 283 flags)) != 0) 284 return(error); 285 break; 286 } 287 #endif 288 default: 289 if (inet_ntop(afd->a_af, addr, host, 290 hostlen) == NULL) 291 return EAI_SYSTEM; 292 break; 293 } 294 } 295 } 296 return(0); 297 } 298 299 #ifdef INET6 300 static int 301 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, 302 char *host, size_t hostlen, int flags) 303 { 304 size_t numaddrlen; 305 char numaddr[512]; 306 307 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 308 return EAI_SYSTEM; 309 310 numaddrlen = strlen(numaddr); 311 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 312 return EAI_OVERFLOW; 313 strlcpy(host, numaddr, hostlen); 314 315 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 316 char zonebuf[MAXHOSTNAMELEN]; 317 int zonelen; 318 319 zonelen = ip6_sa2str( 320 (const struct sockaddr_in6 *)(const void *)sa, 321 zonebuf, sizeof(zonebuf), flags); 322 if (zonelen < 0) 323 return EAI_OVERFLOW; 324 if (zonelen + 1 + numaddrlen + 1 > hostlen) 325 return EAI_OVERFLOW; 326 327 /* construct <numeric-addr><delim><zoneid> */ 328 memcpy(host + numaddrlen + 1, zonebuf, 329 (size_t)zonelen); 330 host[numaddrlen] = SCOPE_DELIMITER; 331 host[numaddrlen + 1 + zonelen] = '\0'; 332 } 333 334 return 0; 335 } 336 337 /* ARGSUSED */ 338 static int 339 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 340 { 341 unsigned int ifindex; 342 const struct in6_addr *a6; 343 int n; 344 345 ifindex = (unsigned int)sa6->sin6_scope_id; 346 a6 = &sa6->sin6_addr; 347 348 #ifdef NI_NUMERICSCOPE 349 if ((flags & NI_NUMERICSCOPE) != 0) { 350 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 351 if (n < 0 || n >= bufsiz) 352 return -1; 353 else 354 return n; 355 } 356 #endif 357 358 /* if_indextoname() does not take buffer size. not a good api... */ 359 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 360 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 361 char *p = if_indextoname(ifindex, buf); 362 if (p) { 363 return(strlen(p)); 364 } 365 } 366 367 /* last resort */ 368 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 369 if (n < 0 || (size_t)n >= bufsiz) 370 return -1; 371 else 372 return n; 373 } 374 #endif /* INET6 */ 375 376 /* 377 * getnameinfo_link(): 378 * Format a link-layer address into a printable format, paying attention to 379 * the interface type. 380 */ 381 /* ARGSUSED */ 382 static int 383 getnameinfo_link(const struct sockaddr *sa, socklen_t salen, 384 char *host, size_t hostlen, char *serv, size_t servlen, int flags) 385 { 386 const struct sockaddr_dl *sdl = 387 (const struct sockaddr_dl *)(const void *)sa; 388 int n; 389 390 if (serv != NULL && servlen > 0) 391 *serv = '\0'; 392 393 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 394 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 395 if (n > hostlen) { 396 *host = '\0'; 397 return EAI_MEMORY; 398 } 399 return 0; 400 } 401 402 switch (sdl->sdl_type) { 403 /* 404 * The following have zero-length addresses. 405 * IFT_ATM (net/if_atmsubr.c) 406 * IFT_FAITH (net/if_faith.c) 407 * IFT_GIF (net/if_gif.c) 408 * IFT_LOOP (net/if_loop.c) 409 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) 410 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 411 * IFT_STF (net/if_stf.c) 412 * IFT_L2VLAN (net/if_vlan.c) 413 * IFT_BRIDGE (net/if_bridge.h> 414 */ 415 /* 416 * The following use IPv4 addresses as link-layer addresses: 417 * IFT_OTHER (net/if_gre.c) 418 * IFT_OTHER (netinet/ip_ipip.c) 419 */ 420 /* default below is believed correct for all these. */ 421 case IFT_ARCNET: 422 case IFT_ETHER: 423 case IFT_FDDI: 424 case IFT_HIPPI: 425 case IFT_ISO88025: 426 default: 427 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 428 host, hostlen); 429 } 430 } 431 432 static int 433 hexname(cp, len, host, hostlen) 434 const u_int8_t *cp; 435 char *host; 436 size_t len, hostlen; 437 { 438 int i, n; 439 char *outp = host; 440 441 *outp = '\0'; 442 for (i = 0; i < len; i++) { 443 n = snprintf(outp, hostlen, "%s%02x", 444 i ? ":" : "", cp[i]); 445 if (n < 0 || n >= hostlen) { 446 *host = '\0'; 447 return EAI_MEMORY; 448 } 449 outp += n; 450 hostlen -= n; 451 } 452 return 0; 453 } 454