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 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Issues to be discussed: 34 * - Thread safe-ness must be checked 35 * - RFC2553 says that we should raise error on short buffer. X/Open says 36 * we need to truncate the result. We obey RFC2553 (and X/Open should be 37 * modified). ipngwg rough consensus seems to follow RFC2553. 38 * - What is "local" in NI_FQDN? 39 * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other. 40 * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if 41 * sin6_scope_id is filled - standardization status? 42 * XXX breaks backward compat for code that expects no scopeid. 43 * beware on merge. 44 */ 45 46 #include <sys/cdefs.h> 47 __FBSDID("$FreeBSD$"); 48 49 #include <sys/types.h> 50 #include <sys/socket.h> 51 #include <net/if.h> 52 #include <netinet/in.h> 53 #include <arpa/inet.h> 54 #include <arpa/nameser.h> 55 #include <netdb.h> 56 #include <resolv.h> 57 #include <string.h> 58 #include <stddef.h> 59 #include <errno.h> 60 61 static const struct afd { 62 int a_af; 63 int a_addrlen; 64 int a_socklen; 65 int a_off; 66 } afdl [] = { 67 #ifdef INET6 68 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 69 offsetof(struct sockaddr_in6, sin6_addr)}, 70 #endif 71 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 72 offsetof(struct sockaddr_in, sin_addr)}, 73 {0, 0, 0}, 74 }; 75 76 struct sockinet { 77 u_char si_len; 78 u_char si_family; 79 u_short si_port; 80 }; 81 82 #ifdef INET6 83 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 84 size_t, int); 85 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 86 #endif 87 88 int 89 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags) 90 const struct sockaddr *sa; 91 socklen_t salen; 92 char *host; 93 size_t hostlen; 94 char *serv; 95 size_t servlen; 96 int flags; 97 { 98 const struct afd *afd; 99 struct servent *sp; 100 struct hostent *hp; 101 u_short port; 102 int family, i; 103 const char *addr; 104 u_int32_t v4a; 105 int h_error; 106 char numserv[512]; 107 char numaddr[512]; 108 109 if (sa == NULL) 110 return EAI_FAIL; 111 112 if (sa->sa_len != salen) 113 return EAI_FAIL; 114 115 family = sa->sa_family; 116 for (i = 0; afdl[i].a_af; i++) 117 if (afdl[i].a_af == family) { 118 afd = &afdl[i]; 119 goto found; 120 } 121 return EAI_FAMILY; 122 123 found: 124 if (salen != afd->a_socklen) 125 return EAI_FAIL; 126 127 /* network byte order */ 128 port = ((const struct sockinet *)sa)->si_port; 129 addr = (const char *)sa + afd->a_off; 130 131 if (serv == NULL || servlen == 0) { 132 /* 133 * do nothing in this case. 134 * in case you are wondering if "&&" is more correct than 135 * "||" here: rfc2553bis-03 says that serv == NULL OR 136 * servlen == 0 means that the caller does not want the result. 137 */ 138 } else { 139 if (flags & NI_NUMERICSERV) 140 sp = NULL; 141 else { 142 sp = getservbyport(port, 143 (flags & NI_DGRAM) ? "udp" : "tcp"); 144 } 145 if (sp) { 146 if (strlen(sp->s_name) + 1 > servlen) 147 return EAI_MEMORY; 148 strlcpy(serv, sp->s_name, servlen); 149 } else { 150 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 151 if (strlen(numserv) + 1 > servlen) 152 return EAI_MEMORY; 153 strlcpy(serv, numserv, servlen); 154 } 155 } 156 157 switch (sa->sa_family) { 158 case AF_INET: 159 v4a = (u_int32_t) 160 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 161 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 162 flags |= NI_NUMERICHOST; 163 v4a >>= IN_CLASSA_NSHIFT; 164 if (v4a == 0) 165 flags |= NI_NUMERICHOST; 166 break; 167 #ifdef INET6 168 case AF_INET6: 169 { 170 const struct sockaddr_in6 *sin6; 171 sin6 = (const struct sockaddr_in6 *)sa; 172 switch (sin6->sin6_addr.s6_addr[0]) { 173 case 0x00: 174 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 175 ; 176 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 177 ; 178 else 179 flags |= NI_NUMERICHOST; 180 break; 181 default: 182 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 183 flags |= NI_NUMERICHOST; 184 } 185 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 186 flags |= NI_NUMERICHOST; 187 break; 188 } 189 } 190 break; 191 #endif 192 } 193 if (host == NULL || hostlen == 0) { 194 /* 195 * do nothing in this case. 196 * in case you are wondering if "&&" is more correct than 197 * "||" here: rfc2553bis-03 says that host == NULL or 198 * hostlen == 0 means that the caller does not want the result. 199 */ 200 } else if (flags & NI_NUMERICHOST) { 201 int numaddrlen; 202 203 /* NUMERICHOST and NAMEREQD conflicts with each other */ 204 if (flags & NI_NAMEREQD) 205 return EAI_NONAME; 206 207 switch(afd->a_af) { 208 #ifdef INET6 209 case AF_INET6: 210 { 211 int error; 212 213 if ((error = ip6_parsenumeric(sa, addr, host, 214 hostlen, flags)) != 0) 215 return(error); 216 break; 217 } 218 #endif 219 default: 220 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 221 == NULL) 222 return EAI_SYSTEM; 223 numaddrlen = strlen(numaddr); 224 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 225 return EAI_MEMORY; 226 strlcpy(host, numaddr, hostlen); 227 break; 228 } 229 } else { 230 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 231 232 if (hp) { 233 #if 0 234 /* 235 * commented out, since "for local host" is not 236 * implemented here - see RFC2553 p30 237 */ 238 if (flags & NI_NOFQDN) { 239 char *p; 240 p = strchr(hp->h_name, '.'); 241 if (p) 242 *p = '\0'; 243 } 244 #endif 245 if (strlen(hp->h_name) + 1 > hostlen) { 246 freehostent(hp); 247 return EAI_MEMORY; 248 } 249 strlcpy(host, hp->h_name, hostlen); 250 freehostent(hp); 251 } else { 252 if (flags & NI_NAMEREQD) 253 return EAI_NONAME; 254 switch(afd->a_af) { 255 #ifdef INET6 256 case AF_INET6: 257 { 258 int error; 259 260 if ((error = ip6_parsenumeric(sa, addr, host, 261 hostlen, 262 flags)) != 0) 263 return(error); 264 break; 265 } 266 #endif 267 default: 268 if (inet_ntop(afd->a_af, addr, host, 269 hostlen) == NULL) 270 return EAI_SYSTEM; 271 break; 272 } 273 } 274 } 275 return(0); 276 } 277 278 #ifdef INET6 279 static int 280 ip6_parsenumeric(sa, addr, host, hostlen, flags) 281 const struct sockaddr *sa; 282 const char *addr; 283 char *host; 284 size_t hostlen; 285 int flags; 286 { 287 int numaddrlen; 288 char numaddr[512]; 289 290 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 291 return EAI_SYSTEM; 292 293 numaddrlen = strlen(numaddr); 294 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 295 return EAI_MEMORY; 296 strlcpy(host, numaddr, hostlen); 297 298 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 299 char zonebuf[MAXHOSTNAMELEN]; 300 int zonelen; 301 302 zonelen = ip6_sa2str( 303 (const struct sockaddr_in6 *)(const void *)sa, 304 zonebuf, sizeof(zonebuf), flags); 305 if (zonelen < 0) 306 return EAI_MEMORY; 307 if (zonelen + 1 + numaddrlen + 1 > hostlen) 308 return EAI_MEMORY; 309 310 /* construct <numeric-addr><delim><zoneid> */ 311 memcpy(host + numaddrlen + 1, zonebuf, 312 (size_t)zonelen); 313 host[numaddrlen] = SCOPE_DELIMITER; 314 host[numaddrlen + 1 + zonelen] = '\0'; 315 } 316 317 return 0; 318 } 319 320 /* ARGSUSED */ 321 static int 322 ip6_sa2str(sa6, buf, bufsiz, flags) 323 const struct sockaddr_in6 *sa6; 324 char *buf; 325 size_t bufsiz; 326 int flags; 327 { 328 unsigned int ifindex; 329 const struct in6_addr *a6; 330 int n; 331 332 ifindex = (unsigned int)sa6->sin6_scope_id; 333 a6 = &sa6->sin6_addr; 334 335 #ifdef NI_NUMERICSCOPE 336 if ((flags & NI_NUMERICSCOPE) != 0) { 337 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 338 if (n < 0 || n >= bufsiz) 339 return -1; 340 else 341 return n; 342 } 343 #endif 344 345 /* if_indextoname() does not take buffer size. not a good api... */ 346 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 347 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 348 char *p = if_indextoname(ifindex, buf); 349 if (p) { 350 return(strlen(p)); 351 } 352 } 353 354 /* last resort */ 355 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 356 if (n < 0 || n >= bufsiz) 357 return -1; 358 else 359 return n; 360 } 361 #endif /* INET6 */ 362