1 /* $NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos Exp $ */ 2 /* $KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $ */ 3 4 /* 5 * Copyright (c) 2000 Ben Harris. 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/cdefs.h> 49 #if defined(LIBC_SCCS) && !defined(lint) 50 __RCSID("$NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos Exp $"); 51 #endif /* LIBC_SCCS and not lint */ 52 53 #include <sys/types.h> 54 #include <sys/socket.h> 55 #include <sys/un.h> 56 #include <net/if.h> 57 #include <netinet/in.h> 58 #include <arpa/inet.h> 59 #include <assert.h> 60 #include <limits.h> 61 #include <netdb.h> 62 #include <arpa/nameser.h> 63 #include "resolv_netid.h" 64 #include "resolv_private.h" 65 #include <stdlib.h> 66 #include <unistd.h> 67 #include <errno.h> 68 #include <stddef.h> 69 #include <string.h> 70 71 static const struct afd { 72 int a_af; 73 socklen_t a_addrlen; 74 socklen_t a_socklen; 75 int a_off; 76 } afdl [] = { 77 #ifdef INET6 78 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 79 offsetof(struct sockaddr_in6, sin6_addr)}, 80 #endif 81 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 82 offsetof(struct sockaddr_in, sin_addr)}, 83 {0, 0, 0, 0}, 84 }; 85 86 struct sockinet { 87 u_char si_len; 88 u_char si_family; 89 u_short si_port; 90 }; 91 92 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 93 socklen_t, char *, socklen_t, int, unsigned, unsigned); 94 #ifdef INET6 95 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 96 socklen_t, int); 97 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 98 #endif 99 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *, 100 socklen_t, char *, socklen_t, int); 101 102 /* 103 * Top-level getnameinfo() code. Look at the address family, and pick an 104 * appropriate function to call. 105 */ 106 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, 107 char* serv, size_t servlen, int flags) 108 { 109 return android_getnameinfofornet(sa, salen, host, hostlen, serv, servlen, flags, 110 NETID_UNSET, MARK_UNSET); 111 } 112 113 int android_getnameinfofornet(const struct sockaddr* sa, socklen_t salen, char* host, 114 size_t hostlen, char* serv, size_t servlen, int flags, unsigned netid, 115 unsigned mark) 116 { 117 switch (sa->sa_family) { 118 case AF_INET: 119 case AF_INET6: 120 return getnameinfo_inet(sa, salen, host, hostlen, 121 serv, servlen, flags, netid, mark); 122 case AF_LOCAL: 123 return getnameinfo_local(sa, salen, host, hostlen, 124 serv, servlen, flags); 125 default: 126 return EAI_FAMILY; 127 } 128 } 129 130 /* 131 * getnameinfo_local(): 132 * Format an local address into a printable format. 133 */ 134 /* ARGSUSED */ 135 static int 136 getnameinfo_local(const struct sockaddr *sa, socklen_t salen, 137 char *host, socklen_t hostlen, char *serv, socklen_t servlen, 138 int flags __attribute__((unused))) 139 { 140 const struct sockaddr_un *sun = 141 (const struct sockaddr_un *)(const void *)sa; 142 143 if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) { 144 return EAI_FAMILY; 145 } 146 147 if (serv != NULL && servlen > 0) 148 serv[0] = '\0'; 149 150 if (host && hostlen > 0) 151 strlcpy(host, sun->sun_path, 152 MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen)); 153 154 return 0; 155 } 156 157 /* 158 * getnameinfo_inet(): 159 * Format an IPv4 or IPv6 sockaddr into a printable string. 160 */ 161 static int 162 getnameinfo_inet(const struct sockaddr* sa, socklen_t salen, 163 char *host, socklen_t hostlen, 164 char *serv, socklen_t servlen, 165 int flags, unsigned netid, unsigned mark) 166 { 167 const struct afd *afd; 168 struct servent *sp; 169 struct hostent *hp; 170 u_short port; 171 int family, i; 172 const char *addr; 173 uint32_t v4a; 174 char numserv[512]; 175 char numaddr[512]; 176 177 /* sa is checked below */ 178 /* host may be NULL */ 179 /* serv may be NULL */ 180 181 if (sa == NULL) 182 return EAI_FAIL; 183 184 family = sa->sa_family; 185 for (i = 0; afdl[i].a_af; i++) 186 if (afdl[i].a_af == family) { 187 afd = &afdl[i]; 188 goto found; 189 } 190 return EAI_FAMILY; 191 192 found: 193 // http://b/1889275: callers should be allowed to provide too much 194 // space, but not too little. 195 if (salen < afd->a_socklen) { 196 return EAI_FAMILY; 197 } 198 199 /* network byte order */ 200 port = ((const struct sockinet *)(const void *)sa)->si_port; 201 addr = (const char *)(const void *)sa + afd->a_off; 202 203 if (serv == NULL || servlen == 0) { 204 /* 205 * do nothing in this case. 206 * in case you are wondering if "&&" is more correct than 207 * "||" here: rfc2553bis-03 says that serv == NULL OR 208 * servlen == 0 means that the caller does not want the result. 209 */ 210 } else { 211 if (flags & NI_NUMERICSERV) 212 sp = NULL; 213 else { 214 sp = getservbyport(port, 215 (flags & NI_DGRAM) ? "udp" : "tcp"); 216 } 217 if (sp) { 218 if (strlen(sp->s_name) + 1 > (size_t)servlen) 219 return EAI_MEMORY; 220 strlcpy(serv, sp->s_name, servlen); 221 } else { 222 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 223 if (strlen(numserv) + 1 > (size_t)servlen) 224 return EAI_MEMORY; 225 strlcpy(serv, numserv, servlen); 226 } 227 } 228 229 switch (sa->sa_family) { 230 case AF_INET: 231 v4a = (uint32_t) 232 ntohl(((const struct sockaddr_in *) 233 (const void *)sa)->sin_addr.s_addr); 234 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 235 flags |= NI_NUMERICHOST; 236 v4a >>= IN_CLASSA_NSHIFT; 237 if (v4a == 0) 238 flags |= NI_NUMERICHOST; 239 break; 240 #ifdef INET6 241 case AF_INET6: 242 { 243 const struct sockaddr_in6 *sin6; 244 sin6 = (const struct sockaddr_in6 *)(const void *)sa; 245 switch (sin6->sin6_addr.s6_addr[0]) { 246 case 0x00: 247 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 248 ; 249 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 250 ; 251 else 252 flags |= NI_NUMERICHOST; 253 break; 254 default: 255 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 256 flags |= NI_NUMERICHOST; 257 } 258 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 259 flags |= NI_NUMERICHOST; 260 break; 261 } 262 } 263 break; 264 #endif 265 } 266 if (host == NULL || hostlen == 0) { 267 /* 268 * do nothing in this case. 269 * in case you are wondering if "&&" is more correct than 270 * "||" here: rfc2553bis-03 says that host == NULL or 271 * hostlen == 0 means that the caller does not want the result. 272 */ 273 } else if (flags & NI_NUMERICHOST) { 274 size_t numaddrlen; 275 276 /* NUMERICHOST and NAMEREQD conflicts with each other */ 277 if (flags & NI_NAMEREQD) 278 return EAI_NONAME; 279 280 switch(afd->a_af) { 281 #ifdef INET6 282 case AF_INET6: 283 { 284 int error; 285 286 if ((error = ip6_parsenumeric(sa, addr, host, 287 hostlen, flags)) != 0) 288 return(error); 289 break; 290 } 291 #endif 292 default: 293 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 294 == NULL) 295 return EAI_SYSTEM; 296 numaddrlen = strlen(numaddr); 297 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 298 return EAI_MEMORY; 299 strlcpy(host, numaddr, hostlen); 300 break; 301 } 302 } else { 303 // This code should only run in the app context, not inside netd, so netid is 304 // the app's netid. netd doesn't use getnameinfo for network requests. 305 const struct android_net_context netcontext = { .app_netid = netid, .app_mark = mark }; 306 hp = android_gethostbyaddrfornetcontext_proxy(addr, afd->a_addrlen, afd->a_af, &netcontext); 307 if (hp) { 308 #if 0 309 /* 310 * commented out, since "for local host" is not 311 * implemented here - see RFC2553 p30 312 */ 313 if (flags & NI_NOFQDN) { 314 char *p; 315 p = strchr(hp->h_name, '.'); 316 if (p) 317 TODO: Before uncommenting rewrite to avoid modifying hp. 318 *p = '\0'; 319 } 320 #endif 321 if (strlen(hp->h_name) + 1 > (size_t)hostlen) { 322 return EAI_MEMORY; 323 } 324 strlcpy(host, hp->h_name, hostlen); 325 } else { 326 if (flags & NI_NAMEREQD) 327 return EAI_NONAME; 328 switch(afd->a_af) { 329 #ifdef INET6 330 case AF_INET6: 331 { 332 int error; 333 334 if ((error = ip6_parsenumeric(sa, addr, host, 335 hostlen, 336 flags)) != 0) 337 return(error); 338 break; 339 } 340 #endif 341 default: 342 if (inet_ntop(afd->a_af, addr, host, 343 hostlen) == NULL) 344 return EAI_SYSTEM; 345 break; 346 } 347 } 348 } 349 return(0); 350 } 351 352 #ifdef INET6 353 static int 354 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 355 socklen_t hostlen, int flags) 356 { 357 size_t numaddrlen; 358 char numaddr[512]; 359 360 assert(sa != NULL); 361 assert(addr != NULL); 362 assert(host != NULL); 363 364 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 365 return EAI_SYSTEM; 366 367 numaddrlen = strlen(numaddr); 368 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 369 return EAI_OVERFLOW; 370 strlcpy(host, numaddr, hostlen); 371 372 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { 373 char zonebuf[MAXHOSTNAMELEN]; 374 int zonelen; 375 376 zonelen = ip6_sa2str( 377 (const struct sockaddr_in6 *)(const void *)sa, 378 zonebuf, sizeof(zonebuf), flags); 379 if (zonelen < 0) 380 return EAI_OVERFLOW; 381 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) 382 return EAI_OVERFLOW; 383 /* construct <numeric-addr><delim><zoneid> */ 384 memcpy(host + numaddrlen + 1, zonebuf, 385 (size_t)zonelen); 386 host[numaddrlen] = SCOPE_DELIMITER; 387 host[numaddrlen + 1 + zonelen] = '\0'; 388 } 389 390 return 0; 391 } 392 393 /* ARGSUSED */ 394 static int 395 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 396 { 397 unsigned int ifindex; 398 const struct in6_addr *a6; 399 int n; 400 401 assert(sa6 != NULL); 402 assert(buf != NULL); 403 404 ifindex = (unsigned int)sa6->sin6_scope_id; 405 a6 = &sa6->sin6_addr; 406 407 #ifdef NI_NUMERICSCOPE 408 if ((flags & NI_NUMERICSCOPE) != 0) { 409 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 410 if (n < 0 || n >= bufsiz) 411 return -1; 412 else 413 return n; 414 } 415 #endif 416 417 /* if_indextoname() does not take buffer size. not a good api... */ 418 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && 419 bufsiz >= IF_NAMESIZE) { 420 char *p = if_indextoname(ifindex, buf); 421 if (p) { 422 return(strlen(p)); 423 } 424 } 425 426 /* last resort */ 427 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 428 if (n < 0 || (size_t) n >= bufsiz) 429 return -1; 430 else 431 return n; 432 } 433 #endif /* INET6 */ 434
