1 /* $FreeBSD: src/lib/libc/net/getnameinfo.c,v 1.20 2007/02/28 21:18:38 bms Exp $ */ 2 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * Copyright (c) 2000 Ben Harris. 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/types.h> 49 #include <sys/socket.h> 50 #include <net/if.h> 51 #include <net/if_dl.h> 52 #include <net/if_types.h> 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 #include <arpa/nameser.h> 56 #include <netdb.h> 57 #include <resolv.h> 58 #include <string.h> 59 #include <stddef.h> 60 #include <errno.h> 61 62 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 63 size_t, char *, size_t, int); 64 #ifdef INET6 65 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 66 size_t, int); 67 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 68 #endif 69 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *, 70 size_t, char *, size_t, int); 71 static int hexname(const u_int8_t *, size_t, char *, size_t); 72 73 int 74 getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, 75 size_t hostlen, char *serv, size_t servlen, int flags) 76 { 77 78 switch (sa->sa_family) { 79 case AF_INET: 80 #ifdef INET6 81 case AF_INET6: 82 #endif 83 return getnameinfo_inet(sa, salen, host, hostlen, serv, 84 servlen, flags); 85 case AF_LINK: 86 return getnameinfo_link(sa, salen, host, hostlen, serv, 87 servlen, flags); 88 default: 89 return EAI_FAMILY; 90 } 91 } 92 93 static const struct afd { 94 int a_af; 95 size_t a_addrlen; 96 socklen_t a_socklen; 97 int a_off; 98 } afdl [] = { 99 #ifdef INET6 100 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 101 offsetof(struct sockaddr_in6, sin6_addr)}, 102 #endif 103 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 104 offsetof(struct sockaddr_in, sin_addr)}, 105 { .a_af = 0 }, 106 }; 107 108 struct sockinet { 109 u_char si_len; 110 u_char si_family; 111 u_short si_port; 112 }; 113 114 static int 115 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen, char *host, 116 size_t hostlen, char *serv, size_t servlen, int flags) 117 { 118 const struct afd *afd; 119 struct servent *sp; 120 struct hostent *hp; 121 u_short port; 122 int family, i; 123 const char *addr; 124 u_int32_t v4a; 125 int h_error; 126 char numserv[512]; 127 char numaddr[512]; 128 129 if (sa == NULL) 130 return EAI_FAIL; 131 132 family = sa->sa_family; 133 for (i = 0; afdl[i].a_af; i++) 134 if (afdl[i].a_af == family) { 135 afd = &afdl[i]; 136 goto found; 137 } 138 return EAI_FAMILY; 139 140 found: 141 if (salen != afd->a_socklen) 142 return EAI_FAIL; 143 144 /* network byte order */ 145 port = ((const struct sockinet *)sa)->si_port; 146 addr = (const char *)sa + afd->a_off; 147 148 if (serv == NULL || servlen == 0) { 149 /* 150 * do nothing in this case. 151 * in case you are wondering if "&&" is more correct than 152 * "||" here: rfc2553bis-03 says that serv == NULL OR 153 * servlen == 0 means that the caller does not want the result. 154 */ 155 } else { 156 if (flags & NI_NUMERICSERV) 157 sp = NULL; 158 else { 159 sp = getservbyport(port, 160 (flags & NI_DGRAM) ? "udp" : "tcp"); 161 } 162 if (sp) { 163 if (strlen(sp->s_name) + 1 > servlen) 164 return EAI_MEMORY; 165 strlcpy(serv, sp->s_name, servlen); 166 } else { 167 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 168 if (strlen(numserv) + 1 > servlen) 169 return EAI_MEMORY; 170 strlcpy(serv, numserv, servlen); 171 } 172 } 173 174 switch (sa->sa_family) { 175 case AF_INET: 176 v4a = (u_int32_t) 177 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 178 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 179 flags |= NI_NUMERICHOST; 180 v4a >>= IN_CLASSA_NSHIFT; 181 if (v4a == 0) 182 flags |= NI_NUMERICHOST; 183 break; 184 #ifdef INET6 185 case AF_INET6: 186 { 187 const struct sockaddr_in6 *sin6; 188 sin6 = (const struct sockaddr_in6 *)sa; 189 switch (sin6->sin6_addr.s6_addr[0]) { 190 case 0x00: 191 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 192 ; 193 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 194 ; 195 else 196 flags |= NI_NUMERICHOST; 197 break; 198 default: 199 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 200 flags |= NI_NUMERICHOST; 201 } 202 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 203 flags |= NI_NUMERICHOST; 204 break; 205 } 206 } 207 break; 208 #endif 209 } 210 if (host == NULL || hostlen == 0) { 211 /* 212 * do nothing in this case. 213 * in case you are wondering if "&&" is more correct than 214 * "||" here: rfc2553bis-03 says that host == NULL or 215 * hostlen == 0 means that the caller does not want the result. 216 */ 217 } else if (flags & NI_NUMERICHOST) { 218 size_t numaddrlen; 219 220 /* NUMERICHOST and NAMEREQD conflicts with each other */ 221 if (flags & NI_NAMEREQD) 222 return EAI_NONAME; 223 224 switch(afd->a_af) { 225 #ifdef INET6 226 case AF_INET6: 227 { 228 int error; 229 230 if ((error = ip6_parsenumeric(sa, addr, host, 231 hostlen, flags)) != 0) 232 return(error); 233 break; 234 } 235 #endif 236 default: 237 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 238 == NULL) 239 return EAI_SYSTEM; 240 numaddrlen = strlen(numaddr); 241 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 242 return EAI_MEMORY; 243 strlcpy(host, numaddr, hostlen); 244 break; 245 } 246 } else { 247 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 248 249 if (hp) { 250 #if 0 251 /* 252 * commented out, since "for local host" is not 253 * implemented here - see RFC2553 p30 254 */ 255 if (flags & NI_NOFQDN) { 256 char *p; 257 p = strchr(hp->h_name, '.'); 258 if (p) 259 *p = '\0'; 260 } 261 #endif 262 if (strlen(hp->h_name) + 1 > hostlen) { 263 freehostent(hp); 264 return EAI_MEMORY; 265 } 266 strlcpy(host, hp->h_name, hostlen); 267 freehostent(hp); 268 } else { 269 if (flags & NI_NAMEREQD) 270 return EAI_NONAME; 271 switch(afd->a_af) { 272 #ifdef INET6 273 case AF_INET6: 274 { 275 int error; 276 277 if ((error = ip6_parsenumeric(sa, addr, host, 278 hostlen, 279 flags)) != 0) 280 return(error); 281 break; 282 } 283 #endif 284 default: 285 if (inet_ntop(afd->a_af, addr, host, 286 hostlen) == NULL) 287 return EAI_SYSTEM; 288 break; 289 } 290 } 291 } 292 return(0); 293 } 294 295 #ifdef INET6 296 static int 297 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 298 size_t hostlen, int flags) 299 { 300 size_t numaddrlen; 301 char numaddr[512]; 302 303 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 304 return EAI_SYSTEM; 305 306 numaddrlen = strlen(numaddr); 307 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 308 return EAI_OVERFLOW; 309 strlcpy(host, numaddr, hostlen); 310 311 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 312 char zonebuf[MAXHOSTNAMELEN]; 313 int zonelen; 314 315 zonelen = ip6_sa2str( 316 (const struct sockaddr_in6 *)(const void *)sa, 317 zonebuf, sizeof(zonebuf), flags); 318 if (zonelen < 0) 319 return EAI_OVERFLOW; 320 if (zonelen + 1 + numaddrlen + 1 > hostlen) 321 return EAI_OVERFLOW; 322 323 /* construct <numeric-addr><delim><zoneid> */ 324 memcpy(host + numaddrlen + 1, zonebuf, 325 (size_t)zonelen); 326 host[numaddrlen] = SCOPE_DELIMITER; 327 host[numaddrlen + 1 + zonelen] = '\0'; 328 } 329 330 return 0; 331 } 332 333 /* ARGSUSED */ 334 static int 335 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, 336 int flags __unused) 337 { 338 unsigned int ifindex; 339 const struct in6_addr *a6; 340 int n; 341 342 ifindex = (unsigned int)sa6->sin6_scope_id; 343 a6 = &sa6->sin6_addr; 344 345 if ((flags & NI_NUMERICSCOPE) != 0) { 346 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 347 if (n < 0 || n >= bufsiz) 348 return -1; 349 else 350 return n; 351 } 352 353 /* if_indextoname() does not take buffer size. not a good api... */ 354 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 355 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 356 char *p = if_indextoname(ifindex, buf); 357 if (p) { 358 return(strlen(p)); 359 } 360 } 361 362 /* last resort */ 363 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 364 if (n < 0 || (size_t)n >= bufsiz) 365 return -1; 366 else 367 return n; 368 } 369 #endif /* INET6 */ 370 371 /* 372 * getnameinfo_link(): 373 * Format a link-layer address into a printable format, paying attention to 374 * the interface type. 375 */ 376 /* ARGSUSED */ 377 static int 378 getnameinfo_link(const struct sockaddr *sa, socklen_t salen __unused, 379 char *host, size_t hostlen, char *serv, size_t servlen, 380 int flags __unused) 381 { 382 const struct sockaddr_dl *sdl = 383 (const struct sockaddr_dl *)(const void *)sa; 384 int n; 385 386 if (serv != NULL && servlen > 0) 387 *serv = '\0'; 388 389 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 390 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 391 if (n > hostlen) { 392 *host = '\0'; 393 return EAI_MEMORY; 394 } 395 return 0; 396 } 397 398 switch (sdl->sdl_type) { 399 /* 400 * The following have zero-length addresses. 401 * IFT_GIF (net/gif/if_gif.c) 402 * IFT_LOOP (net/if_loop.c, net/disc/if_disc.c) 403 * IFT_PPP (net/sppp/if_spppsubr.c) 404 * IFT_SLIP (net/sl/if_sl.c) 405 * IFT_STF (net/stf/if_stf.c) 406 * IFT_L2VLAN (net/vlan/if_vlan.c) 407 * IFT_BRIDGE (net/bridge/if_bridge.c) 408 */ 409 /* 410 * The following use IPv4 addresses as link-layer addresses: 411 * IFT_OTHER (net/gre/if_gre.c) 412 * IFT_OTHER (netproto/ipsec/xform_ipip.c) 413 */ 414 /* default below is believed correct for all these. */ 415 case IFT_ARCNET: 416 case IFT_ETHER: 417 case IFT_FDDI: 418 case IFT_HIPPI: 419 case IFT_ISO88025: 420 default: 421 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 422 host, hostlen); 423 } 424 } 425 426 static int 427 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen) 428 { 429 int i, n; 430 char *outp = host; 431 432 *outp = '\0'; 433 for (i = 0; i < len; i++) { 434 n = snprintf(outp, hostlen, "%s%02x", 435 i ? ":" : "", cp[i]); 436 if (n < 0 || n >= hostlen) { 437 *host = '\0'; 438 return EAI_MEMORY; 439 } 440 outp += n; 441 hostlen -= n; 442 } 443 return 0; 444 } 445