1 /* $FreeBSD: src/lib/libc/net/getnameinfo.c,v 1.4.2.5 2002/07/31 10:11:09 ume Exp $ */ 2 /* $DragonFly: src/lib/libc/net/getnameinfo.c,v 1.4 2005/11/13 02:04:47 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 * 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 <netinet/in.h> 52 #include <arpa/inet.h> 53 #include <arpa/nameser.h> 54 #include <netdb.h> 55 #include <resolv.h> 56 #include <string.h> 57 #include <stddef.h> 58 #include <errno.h> 59 60 static const struct afd { 61 int a_af; 62 int a_addrlen; 63 int a_socklen; 64 int a_off; 65 } afdl [] = { 66 #ifdef INET6 67 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 68 offsetof(struct sockaddr_in6, sin6_addr)}, 69 #endif 70 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 71 offsetof(struct sockaddr_in, sin_addr)}, 72 {0, 0, 0}, 73 }; 74 75 struct sockinet { 76 u_char si_len; 77 u_char si_family; 78 u_short si_port; 79 }; 80 81 #ifdef INET6 82 static int ip6_parsenumeric (const struct sockaddr *, const char *, char *, 83 size_t, int); 84 static int ip6_sa2str (const struct sockaddr_in6 *, char *, size_t, int); 85 #endif 86 87 int 88 getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, 89 size_t hostlen, char *serv, size_t servlen, int flags) 90 { 91 const struct afd *afd; 92 struct servent *sp; 93 struct hostent *hp; 94 u_short port; 95 int family, i; 96 const char *addr; 97 u_int32_t v4a; 98 int h_error; 99 char numserv[512]; 100 char numaddr[512]; 101 102 if (sa == NULL) 103 return EAI_FAIL; 104 105 if (sa->sa_len != salen) 106 return EAI_FAIL; 107 108 family = sa->sa_family; 109 for (i = 0; afdl[i].a_af; i++) 110 if (afdl[i].a_af == family) { 111 afd = &afdl[i]; 112 goto found; 113 } 114 return EAI_FAMILY; 115 116 found: 117 if (salen != afd->a_socklen) 118 return EAI_FAIL; 119 120 /* network byte order */ 121 port = ((const struct sockinet *)sa)->si_port; 122 addr = (const char *)sa + afd->a_off; 123 124 if (serv == NULL || servlen == 0) { 125 /* 126 * do nothing in this case. 127 * in case you are wondering if "&&" is more correct than 128 * "||" here: rfc2553bis-03 says that serv == NULL OR 129 * servlen == 0 means that the caller does not want the result. 130 */ 131 } else { 132 if (flags & NI_NUMERICSERV) 133 sp = NULL; 134 else { 135 sp = getservbyport(port, 136 (flags & NI_DGRAM) ? "udp" : "tcp"); 137 } 138 if (sp) { 139 if (strlen(sp->s_name) + 1 > servlen) 140 return EAI_MEMORY; 141 strlcpy(serv, sp->s_name, servlen); 142 } else { 143 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 144 if (strlen(numserv) + 1 > servlen) 145 return EAI_MEMORY; 146 strlcpy(serv, numserv, servlen); 147 } 148 } 149 150 switch (sa->sa_family) { 151 case AF_INET: 152 v4a = (u_int32_t) 153 ntohl(((const struct sockaddr_in *)sa)->sin_addr.s_addr); 154 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 155 flags |= NI_NUMERICHOST; 156 v4a >>= IN_CLASSA_NSHIFT; 157 if (v4a == 0) 158 flags |= NI_NUMERICHOST; 159 break; 160 #ifdef INET6 161 case AF_INET6: 162 { 163 const struct sockaddr_in6 *sin6; 164 sin6 = (const struct sockaddr_in6 *)sa; 165 switch (sin6->sin6_addr.s6_addr[0]) { 166 case 0x00: 167 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 168 ; 169 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 170 ; 171 else 172 flags |= NI_NUMERICHOST; 173 break; 174 default: 175 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 176 flags |= NI_NUMERICHOST; 177 } 178 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 179 flags |= NI_NUMERICHOST; 180 break; 181 } 182 } 183 break; 184 #endif 185 } 186 if (host == NULL || hostlen == 0) { 187 /* 188 * do nothing in this case. 189 * in case you are wondering if "&&" is more correct than 190 * "||" here: rfc2553bis-03 says that host == NULL or 191 * hostlen == 0 means that the caller does not want the result. 192 */ 193 } else if (flags & NI_NUMERICHOST) { 194 int numaddrlen; 195 196 /* NUMERICHOST and NAMEREQD conflicts with each other */ 197 if (flags & NI_NAMEREQD) 198 return EAI_NONAME; 199 200 switch(afd->a_af) { 201 #ifdef INET6 202 case AF_INET6: 203 { 204 int error; 205 206 if ((error = ip6_parsenumeric(sa, addr, host, 207 hostlen, flags)) != 0) 208 return(error); 209 break; 210 } 211 #endif 212 default: 213 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 214 == NULL) 215 return EAI_SYSTEM; 216 numaddrlen = strlen(numaddr); 217 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 218 return EAI_MEMORY; 219 strlcpy(host, numaddr, hostlen); 220 break; 221 } 222 } else { 223 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error); 224 225 if (hp) { 226 #if 0 227 /* 228 * commented out, since "for local host" is not 229 * implemented here - see RFC2553 p30 230 */ 231 if (flags & NI_NOFQDN) { 232 char *p; 233 p = strchr(hp->h_name, '.'); 234 if (p) 235 *p = '\0'; 236 } 237 #endif 238 if (strlen(hp->h_name) + 1 > hostlen) { 239 freehostent(hp); 240 return EAI_MEMORY; 241 } 242 strlcpy(host, hp->h_name, hostlen); 243 freehostent(hp); 244 } else { 245 if (flags & NI_NAMEREQD) 246 return EAI_NONAME; 247 switch(afd->a_af) { 248 #ifdef INET6 249 case AF_INET6: 250 { 251 int error; 252 253 if ((error = ip6_parsenumeric(sa, addr, host, 254 hostlen, 255 flags)) != 0) 256 return(error); 257 break; 258 } 259 #endif 260 default: 261 if (inet_ntop(afd->a_af, addr, host, 262 hostlen) == NULL) 263 return EAI_SYSTEM; 264 break; 265 } 266 } 267 } 268 return(0); 269 } 270 271 #ifdef INET6 272 static int 273 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 274 size_t hostlen, int flags) 275 { 276 int numaddrlen; 277 char numaddr[512]; 278 279 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 280 return EAI_SYSTEM; 281 282 numaddrlen = strlen(numaddr); 283 if (numaddrlen + 1 > hostlen) /* don't forget terminator */ 284 return EAI_MEMORY; 285 strlcpy(host, numaddr, hostlen); 286 287 if (((const struct sockaddr_in6 *)sa)->sin6_scope_id) { 288 char zonebuf[MAXHOSTNAMELEN]; 289 int zonelen; 290 291 zonelen = ip6_sa2str( 292 (const struct sockaddr_in6 *)(const void *)sa, 293 zonebuf, sizeof(zonebuf), flags); 294 if (zonelen < 0) 295 return EAI_MEMORY; 296 if (zonelen + 1 + numaddrlen + 1 > hostlen) 297 return EAI_MEMORY; 298 299 /* construct <numeric-addr><delim><zoneid> */ 300 memcpy(host + numaddrlen + 1, zonebuf, 301 (size_t)zonelen); 302 host[numaddrlen] = SCOPE_DELIMITER; 303 host[numaddrlen + 1 + zonelen] = '\0'; 304 } 305 306 return 0; 307 } 308 309 /* ARGSUSED */ 310 static int 311 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 312 { 313 unsigned int ifindex; 314 const struct in6_addr *a6; 315 int n; 316 317 ifindex = (unsigned int)sa6->sin6_scope_id; 318 a6 = &sa6->sin6_addr; 319 320 #ifdef NI_NUMERICSCOPE 321 if ((flags & NI_NUMERICSCOPE) != 0) { 322 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 323 if (n < 0 || n >= bufsiz) 324 return -1; 325 else 326 return n; 327 } 328 #endif 329 330 /* if_indextoname() does not take buffer size. not a good api... */ 331 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 332 IN6_IS_ADDR_MC_NODELOCAL(a6)) && bufsiz >= IF_NAMESIZE) { 333 char *p = if_indextoname(ifindex, buf); 334 if (p) { 335 return(strlen(p)); 336 } 337 } 338 339 /* last resort */ 340 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 341 if (n < 0 || n >= bufsiz) 342 return -1; 343 else 344 return n; 345 } 346 #endif /* INET6 */ 347