1 /* $FreeBSD: src/lib/libc/net/getnameinfo.c,v 1.20 2007/02/28 21:18:38 bms Exp $ */ 2 /* $DragonFly: src/lib/libc/net/getnameinfo.c,v 1.5 2008/10/04 22:09:17 swildner Exp $ */ 3 /* $KAME: getnameinfo.c,v 1.61 2002/06/27 09:25:47 itojun Exp $ */ 4 5 /* 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * Copyright (c) 2000 Ben Harris. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the project nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * Issues to be discussed: 37 * - Thread safe-ness must be checked 38 * - RFC2553 says that we should raise error on short buffer. X/Open says 39 * we need to truncate the result. We obey RFC2553 (and X/Open should be 40 * modified). ipngwg rough consensus seems to follow RFC2553. 41 * - What is "local" in NI_FQDN? 42 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other. 43 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if 44 * sin6_scope_id is filled - standardization status? 45 * XXX breaks backward compat for code that expects no scopeid. 46 * beware on merge. 47 */ 48 49 #include <sys/types.h> 50 #include <sys/socket.h> 51 #include <net/if.h> 52 #include <net/if_dl.h> 53 #include <net/if_types.h> 54 #include <netinet/in.h> 55 #include <arpa/inet.h> 56 #include <arpa/nameser.h> 57 #include <netdb.h> 58 #include <resolv.h> 59 #include <string.h> 60 #include <stddef.h> 61 #include <errno.h> 62 63 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 64 size_t, char *, size_t, int); 65 #ifdef INET6 66 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 67 size_t, int); 68 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 69 #endif 70 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *, 71 size_t, char *, size_t, int); 72 static int hexname(const u_int8_t *, size_t, char *, size_t); 73 74 int 75 getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, 76 size_t hostlen, char *serv, size_t servlen, int flags) 77 { 78 79 switch (sa->sa_family) { 80 case AF_INET: 81 #ifdef INET6 82 case AF_INET6: 83 #endif 84 return getnameinfo_inet(sa, salen, host, hostlen, serv, 85 servlen, flags); 86 case AF_LINK: 87 return getnameinfo_link(sa, salen, host, hostlen, serv, 88 servlen, flags); 89 default: 90 return EAI_FAMILY; 91 } 92 } 93 94 static const struct afd { 95 int a_af; 96 size_t a_addrlen; 97 socklen_t a_socklen; 98 int a_off; 99 } afdl [] = { 100 #ifdef INET6 101 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 102 offsetof(struct sockaddr_in6, sin6_addr)}, 103 #endif 104 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 105 offsetof(struct sockaddr_in, sin_addr)}, 106 {0, 0, 0}, 107 }; 108 109 struct sockinet { 110 u_char si_len; 111 u_char si_family; 112 u_short si_port; 113 }; 114 115 static int 116 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen, char *host, 117 size_t hostlen, char *serv, size_t servlen, int flags) 118 { 119 const struct afd *afd; 120 struct servent *sp; 121 struct hostent *hp; 122 u_short port; 123 int family, i; 124 const char *addr; 125 u_int32_t v4a; 126 int h_error; 127 char numserv[512]; 128 char numaddr[512]; 129 130 if (sa == NULL) 131 return EAI_FAIL; 132 133 family = sa->sa_family; 134 for (i = 0; afdl[i].a_af; i++) 135 if (afdl[i].a_af == family) { 136 afd = &afdl[i]; 137 goto found; 138 } 139 return EAI_FAMILY; 140 141 found: 142 if (salen != afd->a_socklen) 143 return EAI_FAIL; 144 145 /* network byte order */ 146 port = ((const struct sockinet *)sa)->si_port; 147 addr = (const char *)sa + afd->a_off; 148 149 if (serv == NULL || servlen == 0) { 150 /* 151 * do nothing in this case. 152 * in case you are wondering if "&&" is more correct than 153 * "||" here: rfc2553bis-03 says that serv == NULL OR 154 * servlen == 0 means that the caller does not want the result. 155 */ 156 } else { 157 if (flags & NI_NUMERICSERV) 158 sp = NULL; 159 else { 160 sp = getservbyport(port, 161 (flags & NI_DGRAM) ? "udp" : "tcp"); 162 } 163 if (sp) { 164 if (strlen(sp->s_name) + 1 > servlen) 165 return EAI_MEMORY; 166 strlcpy(serv, sp->s_name, servlen); 167 } else { 168 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 169 if (strlen(numserv) + 1 > servlen) 170 return EAI_MEMORY; 171 strlcpy(serv, numserv, servlen); 172 } 173 } 174 175 switch (sa->sa_family) { 176 case AF_INET: 177 v4a = (u_int32_t) 178 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 179 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 180 flags |= NI_NUMERICHOST; 181 v4a >>= IN_CLASSA_NSHIFT; 182 if (v4a == 0) 183 flags |= NI_NUMERICHOST; 184 break; 185 #ifdef INET6 186 case AF_INET6: 187 { 188 const struct sockaddr_in6 *sin6; 189 sin6 = (const struct sockaddr_in6 *)sa; 190 switch (sin6->sin6_addr.s6_addr[0]) { 191 case 0x00: 192 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 193 ; 194 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 195 ; 196 else 197 flags |= NI_NUMERICHOST; 198 break; 199 default: 200 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 201 flags |= NI_NUMERICHOST; 202 } 203 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 204 flags |= NI_NUMERICHOST; 205 break; 206 } 207 } 208 break; 209 #endif 210 } 211 if (host == NULL || hostlen == 0) { 212 /* 213 * do nothing in this case. 214 * in case you are wondering if "&&" is more correct than 215 * "||" here: rfc2553bis-03 says that host == NULL or 216 * hostlen == 0 means that the caller does not want the result. 217 */ 218 } else if (flags & NI_NUMERICHOST) { 219 size_t numaddrlen; 220 221 /* NUMERICHOST and NAMEREQD conflicts with each other */ 222 if (flags & NI_NAMEREQD) 223 return EAI_NONAME; 224 225 switch(afd->a_af) { 226 #ifdef INET6 227 case AF_INET6: 228 { 229 int error; 230 231 if ((error = ip6_parsenumeric(sa, addr, host, 232 hostlen, flags)) != 0) 233 return(error); 234 break; 235 } 236 #endif 237 default: 238 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 239 == NULL) 240 return EAI_SYSTEM; 241 numaddrlen = strlen(numaddr); 242 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 243 return EAI_MEMORY; 244 strlcpy(host, numaddr, hostlen); 245 break; 246 } 247 } else { 248 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 249 250 if (hp) { 251 #if 0 252 /* 253 * commented out, since "for local host" is not 254 * implemented here - see RFC2553 p30 255 */ 256 if (flags & NI_NOFQDN) { 257 char *p; 258 p = strchr(hp->h_name, '.'); 259 if (p) 260 *p = '\0'; 261 } 262 #endif 263 if (strlen(hp->h_name) + 1 > hostlen) { 264 freehostent(hp); 265 return EAI_MEMORY; 266 } 267 strlcpy(host, hp->h_name, hostlen); 268 freehostent(hp); 269 } else { 270 if (flags & NI_NAMEREQD) 271 return EAI_NONAME; 272 switch(afd->a_af) { 273 #ifdef INET6 274 case AF_INET6: 275 { 276 int error; 277 278 if ((error = ip6_parsenumeric(sa, addr, host, 279 hostlen, 280 flags)) != 0) 281 return(error); 282 break; 283 } 284 #endif 285 default: 286 if (inet_ntop(afd->a_af, addr, host, 287 hostlen) == NULL) 288 return EAI_SYSTEM; 289 break; 290 } 291 } 292 } 293 return(0); 294 } 295 296 #ifdef INET6 297 static int 298 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 299 size_t hostlen, int flags) 300 { 301 size_t numaddrlen; 302 char numaddr[512]; 303 304 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 305 return EAI_SYSTEM; 306 307 numaddrlen = strlen(numaddr); 308 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 309 return EAI_OVERFLOW; 310 strlcpy(host, numaddr, hostlen); 311 312 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 313 char zonebuf[MAXHOSTNAMELEN]; 314 int zonelen; 315 316 zonelen = ip6_sa2str( 317 (const struct sockaddr_in6 *)(const void *)sa, 318 zonebuf, sizeof(zonebuf), flags); 319 if (zonelen < 0) 320 return EAI_OVERFLOW; 321 if (zonelen + 1 + numaddrlen + 1 > hostlen) 322 return EAI_OVERFLOW; 323 324 /* construct <numeric-addr><delim><zoneid> */ 325 memcpy(host + numaddrlen + 1, zonebuf, 326 (size_t)zonelen); 327 host[numaddrlen] = SCOPE_DELIMITER; 328 host[numaddrlen + 1 + zonelen] = '\0'; 329 } 330 331 return 0; 332 } 333 334 /* ARGSUSED */ 335 static int 336 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 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 #ifdef NI_NUMERICSCOPE 346 if ((flags & NI_NUMERICSCOPE) != 0) { 347 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 348 if (n < 0 || n >= bufsiz) 349 return -1; 350 else 351 return n; 352 } 353 #endif 354 355 /* if_indextoname() does not take buffer size. not a good api... */ 356 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 357 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 358 char *p = if_indextoname(ifindex, buf); 359 if (p) { 360 return(strlen(p)); 361 } 362 } 363 364 /* last resort */ 365 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 366 if (n < 0 || (size_t)n >= bufsiz) 367 return -1; 368 else 369 return n; 370 } 371 #endif /* INET6 */ 372 373 /* 374 * getnameinfo_link(): 375 * Format a link-layer address into a printable format, paying attention to 376 * the interface type. 377 */ 378 /* ARGSUSED */ 379 static int 380 getnameinfo_link(const struct sockaddr *sa, socklen_t salen, char *host, 381 size_t hostlen, char *serv, size_t servlen, int flags) 382 { 383 const struct sockaddr_dl *sdl = 384 (const struct sockaddr_dl *)(const void *)sa; 385 int n; 386 387 if (serv != NULL && servlen > 0) 388 *serv = '\0'; 389 390 if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) { 391 n = snprintf(host, hostlen, "link#%d", sdl->sdl_index); 392 if (n > hostlen) { 393 *host = '\0'; 394 return EAI_MEMORY; 395 } 396 return 0; 397 } 398 399 switch (sdl->sdl_type) { 400 /* 401 * The following have zero-length addresses. 402 * IFT_ATM (net/if_atmsubr.c) 403 * IFT_FAITH (net/if_faith.c) 404 * IFT_GIF (net/if_gif.c) 405 * IFT_LOOP (net/if_loop.c) 406 * IFT_PPP (net/if_ppp.c, net/if_spppsubr.c) 407 * IFT_SLIP (net/if_sl.c, net/if_strip.c) 408 * IFT_STF (net/if_stf.c) 409 * IFT_L2VLAN (net/if_vlan.c) 410 * IFT_BRIDGE (net/if_bridge.h> 411 */ 412 /* 413 * The following use IPv4 addresses as link-layer addresses: 414 * IFT_OTHER (net/if_gre.c) 415 * IFT_OTHER (netinet/ip_ipip.c) 416 */ 417 /* default below is believed correct for all these. */ 418 case IFT_ARCNET: 419 case IFT_ETHER: 420 case IFT_FDDI: 421 case IFT_HIPPI: 422 case IFT_ISO88025: 423 default: 424 return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen, 425 host, hostlen); 426 } 427 } 428 429 static int 430 hexname(const u_int8_t *cp, size_t len, char *host, size_t hostlen) 431 { 432 int i, n; 433 char *outp = host; 434 435 *outp = '\0'; 436 for (i = 0; i < len; i++) { 437 n = snprintf(outp, hostlen, "%s%02x", 438 i ? ":" : "", cp[i]); 439 if (n < 0 || n >= hostlen) { 440 *host = '\0'; 441 return EAI_MEMORY; 442 } 443 outp += n; 444 hostlen -= n; 445 } 446 return 0; 447 } 448