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(const struct sockaddr *sa, socklen_t salen, 90 char *host, size_t hostlen, char *serv, size_t servlen, 91 int flags) 92 { 93 const struct afd *afd; 94 struct servent *sp; 95 struct hostent *hp; 96 u_short port; 97 int family, i; 98 const char *addr; 99 u_int32_t v4a; 100 int h_error; 101 char numserv[512]; 102 char numaddr[512]; 103 104 if (sa == NULL) 105 return EAI_FAIL; 106 107 family = sa->sa_family; 108 for (i = 0; afdl[i].a_af; i++) 109 if (afdl[i].a_af == family) { 110 afd = &afdl[i]; 111 goto found; 112 } 113 return EAI_FAMILY; 114 115 found: 116 if (salen != afd->a_socklen) 117 return EAI_FAIL; 118 119 /* network byte order */ 120 port = ((const struct sockinet *)sa)->si_port; 121 addr = (const char *)sa + afd->a_off; 122 123 if (serv == NULL || servlen == 0) { 124 /* 125 * do nothing in this case. 126 * in case you are wondering if "&&" is more correct than 127 * "||" here: rfc2553bis-03 says that serv == NULL OR 128 * servlen == 0 means that the caller does not want the result. 129 */ 130 } else { 131 if (flags & NI_NUMERICSERV) 132 sp = NULL; 133 else { 134 sp = getservbyport(port, 135 (flags & NI_DGRAM) ? "udp" : "tcp"); 136 } 137 if (sp) { 138 if (strlen(sp->s_name) + 1 > servlen) 139 return EAI_MEMORY; 140 strlcpy(serv, sp->s_name, servlen); 141 } else { 142 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 143 if (strlen(numserv) + 1 > servlen) 144 return EAI_MEMORY; 145 strlcpy(serv, numserv, servlen); 146 } 147 } 148 149 switch (sa->sa_family) { 150 case AF_INET: 151 v4a = (u_int32_t) 152 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 153 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 154 flags |= NI_NUMERICHOST; 155 v4a >>= IN_CLASSA_NSHIFT; 156 if (v4a == 0) 157 flags |= NI_NUMERICHOST; 158 break; 159 #ifdef INET6 160 case AF_INET6: 161 { 162 const struct sockaddr_in6 *sin6; 163 sin6 = (const struct sockaddr_in6 *)sa; 164 switch (sin6->sin6_addr.s6_addr[0]) { 165 case 0x00: 166 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 167 ; 168 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 169 ; 170 else 171 flags |= NI_NUMERICHOST; 172 break; 173 default: 174 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 175 flags |= NI_NUMERICHOST; 176 } 177 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 178 flags |= NI_NUMERICHOST; 179 break; 180 } 181 } 182 break; 183 #endif 184 } 185 if (host == NULL || hostlen == 0) { 186 /* 187 * do nothing in this case. 188 * in case you are wondering if "&&" is more correct than 189 * "||" here: rfc2553bis-03 says that host == NULL or 190 * hostlen == 0 means that the caller does not want the result. 191 */ 192 } else if (flags & NI_NUMERICHOST) { 193 size_t numaddrlen; 194 195 /* NUMERICHOST and NAMEREQD conflicts with each other */ 196 if (flags & NI_NAMEREQD) 197 return EAI_NONAME; 198 199 switch(afd->a_af) { 200 #ifdef INET6 201 case AF_INET6: 202 { 203 int error; 204 205 if ((error = ip6_parsenumeric(sa, addr, host, 206 hostlen, flags)) != 0) 207 return(error); 208 break; 209 } 210 #endif 211 default: 212 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 213 == NULL) 214 return EAI_SYSTEM; 215 numaddrlen = strlen(numaddr); 216 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 217 return EAI_MEMORY; 218 strlcpy(host, numaddr, hostlen); 219 break; 220 } 221 } else { 222 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 223 224 if (hp) { 225 #if 0 226 /* 227 * commented out, since "for local host" is not 228 * implemented here - see RFC2553 p30 229 */ 230 if (flags & NI_NOFQDN) { 231 char *p; 232 p = strchr(hp->h_name, '.'); 233 if (p) 234 *p = '\0'; 235 } 236 #endif 237 if (strlen(hp->h_name) + 1 > hostlen) { 238 freehostent(hp); 239 return EAI_MEMORY; 240 } 241 strlcpy(host, hp->h_name, hostlen); 242 freehostent(hp); 243 } else { 244 if (flags & NI_NAMEREQD) 245 return EAI_NONAME; 246 switch(afd->a_af) { 247 #ifdef INET6 248 case AF_INET6: 249 { 250 int error; 251 252 if ((error = ip6_parsenumeric(sa, addr, host, 253 hostlen, 254 flags)) != 0) 255 return(error); 256 break; 257 } 258 #endif 259 default: 260 if (inet_ntop(afd->a_af, addr, host, 261 hostlen) == NULL) 262 return EAI_SYSTEM; 263 break; 264 } 265 } 266 } 267 return(0); 268 } 269 270 #ifdef INET6 271 static int 272 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, 273 char *host, size_t hostlen, int flags) 274 { 275 size_t numaddrlen; 276 char numaddr[512]; 277 278 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 279 return EAI_SYSTEM; 280 281 numaddrlen = strlen(numaddr); 282 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 283 return EAI_MEMORY; 284 strlcpy(host, numaddr, hostlen); 285 286 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 287 char zonebuf[MAXHOSTNAMELEN]; 288 int zonelen; 289 290 zonelen = ip6_sa2str( 291 (const struct sockaddr_in6 *)(const void *)sa, 292 zonebuf, sizeof(zonebuf), flags); 293 if (zonelen < 0) 294 return EAI_MEMORY; 295 if (zonelen + 1 + numaddrlen + 1 > hostlen) 296 return EAI_MEMORY; 297 298 /* construct <numeric-addr><delim><zoneid> */ 299 memcpy(host + numaddrlen + 1, zonebuf, 300 (size_t)zonelen); 301 host[numaddrlen] = SCOPE_DELIMITER; 302 host[numaddrlen + 1 + zonelen] = '\0'; 303 } 304 305 return 0; 306 } 307 308 /* ARGSUSED */ 309 static int 310 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 311 { 312 unsigned int ifindex; 313 const struct in6_addr *a6; 314 int n; 315 316 ifindex = (unsigned int)sa6->sin6_scope_id; 317 a6 = &sa6->sin6_addr; 318 319 #ifdef NI_NUMERICSCOPE 320 if ((flags & NI_NUMERICSCOPE) != 0) { 321 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 322 if (n < 0 || n >= bufsiz) 323 return -1; 324 else 325 return n; 326 } 327 #endif 328 329 /* if_indextoname() does not take buffer size. not a good api... */ 330 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 331 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 332 char *p = if_indextoname(ifindex, buf); 333 if (p) { 334 return(strlen(p)); 335 } 336 } 337 338 /* last resort */ 339 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 340 if (n < 0 || (size_t)n >= bufsiz) 341 return -1; 342 else 343 return n; 344 } 345 #endif /* INET6 */ 346