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 size_t a_addrlen; 64 socklen_t 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 family = sa->sa_family; 113 for (i = 0; afdl[i].a_af; i++) 114 if (afdl[i].a_af == family) { 115 afd = &afdl[i]; 116 goto found; 117 } 118 return EAI_FAMILY; 119 120 found: 121 if (salen != afd->a_socklen) 122 return EAI_FAIL; 123 124 /* network byte order */ 125 port = ((const struct sockinet *)sa)->si_port; 126 addr = (const char *)sa + afd->a_off; 127 128 if (serv == NULL || servlen == 0) { 129 /* 130 * do nothing in this case. 131 * in case you are wondering if "&&" is more correct than 132 * "||" here: rfc2553bis-03 says that serv == NULL OR 133 * servlen == 0 means that the caller does not want the result. 134 */ 135 } else { 136 if (flags & NI_NUMERICSERV) 137 sp = NULL; 138 else { 139 sp = getservbyport(port, 140 (flags & NI_DGRAM) ? "udp" : "tcp"); 141 } 142 if (sp) { 143 if (strlen(sp->s_name) + 1 > servlen) 144 return EAI_MEMORY; 145 strlcpy(serv, sp->s_name, servlen); 146 } else { 147 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 148 if (strlen(numserv) + 1 > servlen) 149 return EAI_MEMORY; 150 strlcpy(serv, numserv, servlen); 151 } 152 } 153 154 switch (sa->sa_family) { 155 case AF_INET: 156 v4a = (u_int32_t) 157 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 158 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 159 flags |= NI_NUMERICHOST; 160 v4a >>= IN_CLASSA_NSHIFT; 161 if (v4a == 0) 162 flags |= NI_NUMERICHOST; 163 break; 164 #ifdef INET6 165 case AF_INET6: 166 { 167 const struct sockaddr_in6 *sin6; 168 sin6 = (const struct sockaddr_in6 *)sa; 169 switch (sin6->sin6_addr.s6_addr[0]) { 170 case 0x00: 171 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 172 ; 173 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 174 ; 175 else 176 flags |= NI_NUMERICHOST; 177 break; 178 default: 179 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 180 flags |= NI_NUMERICHOST; 181 } 182 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 183 flags |= NI_NUMERICHOST; 184 break; 185 } 186 } 187 break; 188 #endif 189 } 190 if (host == NULL || hostlen == 0) { 191 /* 192 * do nothing in this case. 193 * in case you are wondering if "&&" is more correct than 194 * "||" here: rfc2553bis-03 says that host == NULL or 195 * hostlen == 0 means that the caller does not want the result. 196 */ 197 } else if (flags & NI_NUMERICHOST) { 198 size_t numaddrlen; 199 200 /* NUMERICHOST and NAMEREQD conflicts with each other */ 201 if (flags & NI_NAMEREQD) 202 return EAI_NONAME; 203 204 switch(afd->a_af) { 205 #ifdef INET6 206 case AF_INET6: 207 { 208 int error; 209 210 if ((error = ip6_parsenumeric(sa, addr, host, 211 hostlen, flags)) != 0) 212 return(error); 213 break; 214 } 215 #endif 216 default: 217 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 218 == NULL) 219 return EAI_SYSTEM; 220 numaddrlen = strlen(numaddr); 221 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 222 return EAI_MEMORY; 223 strlcpy(host, numaddr, hostlen); 224 break; 225 } 226 } else { 227 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 228 229 if (hp) { 230 #if 0 231 /* 232 * commented out, since "for local host" is not 233 * implemented here - see RFC2553 p30 234 */ 235 if (flags & NI_NOFQDN) { 236 char *p; 237 p = strchr(hp->h_name, '.'); 238 if (p) 239 *p = '\0'; 240 } 241 #endif 242 if (strlen(hp->h_name) + 1 > hostlen) { 243 freehostent(hp); 244 return EAI_MEMORY; 245 } 246 strlcpy(host, hp->h_name, hostlen); 247 freehostent(hp); 248 } else { 249 if (flags & NI_NAMEREQD) 250 return EAI_NONAME; 251 switch(afd->a_af) { 252 #ifdef INET6 253 case AF_INET6: 254 { 255 int error; 256 257 if ((error = ip6_parsenumeric(sa, addr, host, 258 hostlen, 259 flags)) != 0) 260 return(error); 261 break; 262 } 263 #endif 264 default: 265 if (inet_ntop(afd->a_af, addr, host, 266 hostlen) == NULL) 267 return EAI_SYSTEM; 268 break; 269 } 270 } 271 } 272 return(0); 273 } 274 275 #ifdef INET6 276 static int 277 ip6_parsenumeric(sa, addr, host, hostlen, flags) 278 const struct sockaddr *sa; 279 const char *addr; 280 char *host; 281 size_t hostlen; 282 int flags; 283 { 284 size_t numaddrlen; 285 char numaddr[512]; 286 287 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 288 return EAI_SYSTEM; 289 290 numaddrlen = strlen(numaddr); 291 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 292 return EAI_MEMORY; 293 strlcpy(host, numaddr, hostlen); 294 295 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 296 char zonebuf[MAXHOSTNAMELEN]; 297 int zonelen; 298 299 zonelen = ip6_sa2str( 300 (const struct sockaddr_in6 *)(const void *)sa, 301 zonebuf, sizeof(zonebuf), flags); 302 if (zonelen < 0) 303 return EAI_MEMORY; 304 if (zonelen + 1 + numaddrlen + 1 > hostlen) 305 return EAI_MEMORY; 306 307 /* construct <numeric-addr><delim><zoneid> */ 308 memcpy(host + numaddrlen + 1, zonebuf, 309 (size_t)zonelen); 310 host[numaddrlen] = SCOPE_DELIMITER; 311 host[numaddrlen + 1 + zonelen] = '\0'; 312 } 313 314 return 0; 315 } 316 317 /* ARGSUSED */ 318 static int 319 ip6_sa2str(sa6, buf, bufsiz, flags) 320 const struct sockaddr_in6 *sa6; 321 char *buf; 322 size_t bufsiz; 323 int flags; 324 { 325 unsigned int ifindex; 326 const struct in6_addr *a6; 327 int n; 328 329 ifindex = (unsigned int)sa6->sin6_scope_id; 330 a6 = &sa6->sin6_addr; 331 332 #ifdef NI_NUMERICSCOPE 333 if ((flags & NI_NUMERICSCOPE) != 0) { 334 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 335 if (n < 0 || n >= bufsiz) 336 return -1; 337 else 338 return n; 339 } 340 #endif 341 342 /* if_indextoname() does not take buffer size. not a good api... */ 343 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 344 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 345 char *p = if_indextoname(ifindex, buf); 346 if (p) { 347 return(strlen(p)); 348 } 349 } 350 351 /* last resort */ 352 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 353 if (n < 0 || (size_t)n >= bufsiz) 354 return -1; 355 else 356 return n; 357 } 358 #endif /* INET6 */ 359