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 /* This macro is modelled after the ones in <netinet/in6.h>. */ 72 /* RFC 6052, section 2.1 */ 73 #define IN6_IS_ADDR_WKP(a) \ 74 ((((a)->s6_addr32[0]) == ntohl(0x0064ff9b)) && \ 75 (((a)->s6_addr32[1]) == 0) && \ 76 (((a)->s6_addr32[2]) == 0)) 77 78 static const struct afd { 79 int a_af; 80 socklen_t a_addrlen; 81 socklen_t a_socklen; 82 int a_off; 83 } afdl [] = { 84 #ifdef INET6 85 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), 86 offsetof(struct sockaddr_in6, sin6_addr)}, 87 #endif 88 {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), 89 offsetof(struct sockaddr_in, sin_addr)}, 90 {0, 0, 0, 0}, 91 }; 92 93 struct sockinet { 94 u_char si_len; 95 u_char si_family; 96 u_short si_port; 97 }; 98 99 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *, 100 socklen_t, char *, socklen_t, int, unsigned, unsigned); 101 #ifdef INET6 102 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *, 103 socklen_t, int); 104 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int); 105 #endif 106 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *, 107 socklen_t, char *, socklen_t, int); 108 109 /* 110 * Top-level getnameinfo() code. Look at the address family, and pick an 111 * appropriate function to call. 112 */ 113 int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t hostlen, 114 char* serv, size_t servlen, int flags) 115 { 116 return android_getnameinfofornet(sa, salen, host, hostlen, serv, servlen, flags, 117 NETID_UNSET, MARK_UNSET); 118 } 119 120 int android_getnameinfofornet(const struct sockaddr* sa, socklen_t salen, char* host, 121 size_t hostlen, char* serv, size_t servlen, int flags, unsigned netid, 122 unsigned mark) 123 { 124 switch (sa->sa_family) { 125 case AF_INET: 126 case AF_INET6: 127 return getnameinfo_inet(sa, salen, host, hostlen, 128 serv, servlen, flags, netid, mark); 129 case AF_LOCAL: 130 return getnameinfo_local(sa, salen, host, hostlen, 131 serv, servlen, flags); 132 default: 133 return EAI_FAMILY; 134 } 135 } 136 137 /* 138 * getnameinfo_local(): 139 * Format an local address into a printable format. 140 */ 141 /* ARGSUSED */ 142 static int 143 getnameinfo_local(const struct sockaddr *sa, socklen_t salen, 144 char *host, socklen_t hostlen, char *serv, socklen_t servlen, 145 int flags __attribute__((unused))) 146 { 147 const struct sockaddr_un *sun = 148 (const struct sockaddr_un *)(const void *)sa; 149 150 if (salen < (socklen_t) offsetof(struct sockaddr_un, sun_path)) { 151 return EAI_FAMILY; 152 } 153 154 if (serv != NULL && servlen > 0) 155 serv[0] = '\0'; 156 157 if (host && hostlen > 0) 158 strlcpy(host, sun->sun_path, 159 MIN((socklen_t) sizeof(sun->sun_path) + 1, hostlen)); 160 161 return 0; 162 } 163 164 /* 165 * getnameinfo_inet(): 166 * Format an IPv4 or IPv6 sockaddr into a printable string. 167 */ 168 static int 169 getnameinfo_inet(const struct sockaddr* sa, socklen_t salen, 170 char *host, socklen_t hostlen, 171 char *serv, socklen_t servlen, 172 int flags, unsigned netid, unsigned mark) 173 { 174 const struct afd *afd; 175 struct servent *sp; 176 struct hostent *hp; 177 u_short port; 178 int family, i; 179 const char *addr; 180 uint32_t v4a; 181 char numserv[512]; 182 char numaddr[512]; 183 184 /* sa is checked below */ 185 /* host may be NULL */ 186 /* serv may be NULL */ 187 188 if (sa == NULL) 189 return EAI_FAIL; 190 191 family = sa->sa_family; 192 for (i = 0; afdl[i].a_af; i++) 193 if (afdl[i].a_af == family) { 194 afd = &afdl[i]; 195 goto found; 196 } 197 return EAI_FAMILY; 198 199 found: 200 // http://b/1889275: callers should be allowed to provide too much 201 // space, but not too little. 202 if (salen < afd->a_socklen) { 203 return EAI_FAMILY; 204 } 205 206 /* network byte order */ 207 port = ((const struct sockinet *)(const void *)sa)->si_port; 208 addr = (const char *)(const void *)sa + afd->a_off; 209 210 if (serv == NULL || servlen == 0) { 211 /* 212 * do nothing in this case. 213 * in case you are wondering if "&&" is more correct than 214 * "||" here: rfc2553bis-03 says that serv == NULL OR 215 * servlen == 0 means that the caller does not want the result. 216 */ 217 } else { 218 if (flags & NI_NUMERICSERV) 219 sp = NULL; 220 else { 221 sp = getservbyport(port, 222 (flags & NI_DGRAM) ? "udp" : "tcp"); 223 } 224 if (sp) { 225 if (strlen(sp->s_name) + 1 > (size_t)servlen) 226 return EAI_MEMORY; 227 strlcpy(serv, sp->s_name, servlen); 228 } else { 229 snprintf(numserv, sizeof(numserv), "%u", ntohs(port)); 230 if (strlen(numserv) + 1 > (size_t)servlen) 231 return EAI_MEMORY; 232 strlcpy(serv, numserv, servlen); 233 } 234 } 235 236 switch (sa->sa_family) { 237 case AF_INET: 238 v4a = (uint32_t) 239 ntohl(((const struct sockaddr_in *) 240 (const void *)sa)->sin_addr.s_addr); 241 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a)) 242 flags |= NI_NUMERICHOST; 243 v4a >>= IN_CLASSA_NSHIFT; 244 if (v4a == 0) 245 flags |= NI_NUMERICHOST; 246 break; 247 #ifdef INET6 248 case AF_INET6: 249 { 250 const struct sockaddr_in6 *sin6; 251 sin6 = (const struct sockaddr_in6 *)(const void *)sa; 252 switch (sin6->sin6_addr.s6_addr[0]) { 253 case 0x00: 254 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 255 ; 256 else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 257 ; 258 else if (IN6_IS_ADDR_WKP(&sin6->sin6_addr)) 259 ; 260 else 261 flags |= NI_NUMERICHOST; 262 break; 263 default: 264 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 265 flags |= NI_NUMERICHOST; 266 } 267 else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) 268 flags |= NI_NUMERICHOST; 269 break; 270 } 271 } 272 break; 273 #endif 274 } 275 if (host == NULL || hostlen == 0) { 276 /* 277 * do nothing in this case. 278 * in case you are wondering if "&&" is more correct than 279 * "||" here: rfc2553bis-03 says that host == NULL or 280 * hostlen == 0 means that the caller does not want the result. 281 */ 282 } else if (flags & NI_NUMERICHOST) { 283 size_t numaddrlen; 284 285 /* NUMERICHOST and NAMEREQD conflicts with each other */ 286 if (flags & NI_NAMEREQD) 287 return EAI_NONAME; 288 289 switch(afd->a_af) { 290 #ifdef INET6 291 case AF_INET6: 292 { 293 int error; 294 295 if ((error = ip6_parsenumeric(sa, addr, host, 296 hostlen, flags)) != 0) 297 return(error); 298 break; 299 } 300 #endif 301 default: 302 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr)) 303 == NULL) 304 return EAI_SYSTEM; 305 numaddrlen = strlen(numaddr); 306 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 307 return EAI_MEMORY; 308 strlcpy(host, numaddr, hostlen); 309 break; 310 } 311 } else { 312 // This code should only run in the app context, not inside netd, so netid is 313 // the app's netid. netd doesn't use getnameinfo for network requests. 314 const struct android_net_context netcontext = { .app_netid = netid, .app_mark = mark }; 315 hp = android_gethostbyaddrfornetcontext_proxy(addr, afd->a_addrlen, afd->a_af, &netcontext); 316 if (hp) { 317 #if 0 318 /* 319 * commented out, since "for local host" is not 320 * implemented here - see RFC2553 p30 321 */ 322 if (flags & NI_NOFQDN) { 323 char *p; 324 p = strchr(hp->h_name, '.'); 325 if (p) 326 TODO: Before uncommenting rewrite to avoid modifying hp. 327 *p = '\0'; 328 } 329 #endif 330 if (strlen(hp->h_name) + 1 > (size_t)hostlen) { 331 return EAI_MEMORY; 332 } 333 strlcpy(host, hp->h_name, hostlen); 334 } else { 335 if (flags & NI_NAMEREQD) 336 return EAI_NONAME; 337 switch(afd->a_af) { 338 #ifdef INET6 339 case AF_INET6: 340 { 341 int error; 342 343 if ((error = ip6_parsenumeric(sa, addr, host, 344 hostlen, 345 flags)) != 0) 346 return(error); 347 break; 348 } 349 #endif 350 default: 351 if (inet_ntop(afd->a_af, addr, host, 352 hostlen) == NULL) 353 return EAI_SYSTEM; 354 break; 355 } 356 } 357 } 358 return(0); 359 } 360 361 #ifdef INET6 362 static int 363 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host, 364 socklen_t hostlen, int flags) 365 { 366 size_t numaddrlen; 367 char numaddr[512]; 368 369 assert(sa != NULL); 370 assert(addr != NULL); 371 assert(host != NULL); 372 373 if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL) 374 return EAI_SYSTEM; 375 376 numaddrlen = strlen(numaddr); 377 if (numaddrlen + 1 > (size_t)hostlen) /* don't forget terminator */ 378 return EAI_OVERFLOW; 379 strlcpy(host, numaddr, hostlen); 380 381 if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) { 382 char zonebuf[MAXHOSTNAMELEN]; 383 int zonelen; 384 385 zonelen = ip6_sa2str( 386 (const struct sockaddr_in6 *)(const void *)sa, 387 zonebuf, sizeof(zonebuf), flags); 388 if (zonelen < 0) 389 return EAI_OVERFLOW; 390 if ((size_t) zonelen + 1 + numaddrlen + 1 > (size_t)hostlen) 391 return EAI_OVERFLOW; 392 /* construct <numeric-addr><delim><zoneid> */ 393 memcpy(host + numaddrlen + 1, zonebuf, 394 (size_t)zonelen); 395 host[numaddrlen] = SCOPE_DELIMITER; 396 host[numaddrlen + 1 + zonelen] = '\0'; 397 } 398 399 return 0; 400 } 401 402 /* ARGSUSED */ 403 static int 404 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags) 405 { 406 unsigned int ifindex; 407 const struct in6_addr *a6; 408 int n; 409 410 assert(sa6 != NULL); 411 assert(buf != NULL); 412 413 ifindex = (unsigned int)sa6->sin6_scope_id; 414 a6 = &sa6->sin6_addr; 415 416 #ifdef NI_NUMERICSCOPE 417 if ((flags & NI_NUMERICSCOPE) != 0) { 418 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 419 if (n < 0 || n >= bufsiz) 420 return -1; 421 else 422 return n; 423 } 424 #endif 425 426 /* if_indextoname() does not take buffer size. not a good api... */ 427 if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) && 428 bufsiz >= IF_NAMESIZE) { 429 char *p = if_indextoname(ifindex, buf); 430 if (p) { 431 return(strlen(p)); 432 } 433 } 434 435 /* last resort */ 436 n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id); 437 if (n < 0 || (size_t) n >= bufsiz) 438 return -1; 439 else 440 return n; 441 } 442 #endif /* INET6 */ 443
