external/bsd/bind/dist/lib/lwres/getnameinfo.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Portions Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   5  * Portions Copyright (C) 1999-2001, 2003  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /* Id: getnameinfo.c,v 1.39 2007/06/19 23:47:22 tbox Exp */
  21
  22 /*! \file */
  23
  24 /*
  25  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  26  * All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. Neither the name of the project nor the names of its contributors
  37  *    may be used to endorse or promote products derived from this software
  38  *    without specific prior written permission.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  */
  52
  53 /*
  54  * XXX
  55  * Issues to be discussed:
  56  * - Return values.  There seems to be no standard for return value (RFC2553)
  57  *   but INRIA implementation returns EAI_xxx defined for getaddrinfo().
  58  */
  59
  60
  61 /**
  62  *    This function is equivalent to the getnameinfo(3) function defined in
  63  *    RFC2133. lwres_getnameinfo() returns the hostname for the struct
  64  *    sockaddr sa which is salen bytes long. The hostname is of length
  65  *    hostlen and is returned via *host. The maximum length of the hostname
  66  *    is 1025 bytes: #NI_MAXHOST.
  67  *
  68  *    The name of the service associated with the port number in sa is
  69  *    returned in *serv. It is servlen bytes long. The maximum length of the
  70  *    service name is #NI_MAXSERV - 32 bytes.
  71  *
  72  *    The flags argument sets the following bits:
  73  *
  74  * \li   #NI_NOFQDN:
  75  *           A fully qualified domain name is not required for local hosts.
  76  *           The local part of the fully qualified domain name is returned
  77  *           instead.
  78  *
  79  * \li   #NI_NUMERICHOST
  80  *           Return the address in numeric form, as if calling inet_ntop(),
  81  *           instead of a host name.
  82  *
  83  * \li   #NI_NAMEREQD
  84  *           A name is required. If the hostname cannot be found in the DNS
  85  *           and this flag is set, a non-zero error code is returned. If the
  86  *           hostname is not found and the flag is not set, the address is
  87  *           returned in numeric form.
  88  *
  89  * \li   #NI_NUMERICSERV
  90  *           The service name is returned as a digit string representing the
  91  *           port number.
  92  *
  93  * \li   #NI_DGRAM
  94  *           Specifies that the service being looked up is a datagram
  95  *           service, and causes getservbyport() to be called with a second
  96  *           argument of "udp" instead of its default of "tcp". This is
  97  *           required for the few ports (512-514) that have different
  98  *           services for UDP and TCP.
  99  *
 100  * \section getnameinfo_return Return Values
 101  *
 102  *    lwres_getnameinfo() returns 0 on success or a non-zero error code if
 103  *    an error occurs.
 104  *
 105  * \section getname_see See Also
 106  *
 107  *    RFC2133, getservbyport(),
 108  *    lwres_getnamebyaddr(). lwres_net_ntop().
 109  *
 110  * \section getnameinfo_bugs Bugs
 111  *
 112  *    RFC2133 fails to define what the nonzero return values of
 113  *    getnameinfo() are.
 114  */
 115
 116 #include <config.h>
 117
 118 #include <stdio.h>
 119 #include <string.h>
 120
 121 #include <lwres/lwres.h>
 122 #include <lwres/net.h>
 123 #include <lwres/netdb.h>
 124 #include "print_p.h"
 125
 126 #include "assert_p.h"
 127
 128 #define SUCCESS 0
 129
 130 /*% afd structure definition */
 131 static struct afd {
 132         int a_af;
 133         size_t a_addrlen;
 134         size_t a_socklen;
 135 } afdl [] = {
 136         /*!
 137          * First entry is linked last...
 138          */
 139         { AF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in) },
 140         { AF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6) },
 141         {0, 0, 0},
 142 };
 143
 144 #define ENI_NOSERVNAME  1
 145 #define ENI_NOHOSTNAME  2
 146 #define ENI_MEMORY      3
 147 #define ENI_SYSTEM      4
 148 #define ENI_FAMILY      5
 149 #define ENI_SALEN       6
 150 #define ENI_NOSOCKET    7
 151
 152 /*!
 153  * The test against 0 is there to keep the Solaris compiler
 154  * from complaining about "end-of-loop code not reached".
 155  */
 156 #define ERR(code) \
 157         do { result = (code);                   \
 158                 if (result != 0) goto cleanup;  \
 159         } while (0)
 160
 161 /*% lightweight resolver socket address structure to hostname and service name */
 162 int
 163 lwres_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
 164                   size_t hostlen, char *serv, size_t servlen, int flags)
 165 {
 166         struct afd *afd;
 167         struct servent *sp;
 168         unsigned short port;
 169 #ifdef LWRES_PLATFORM_HAVESALEN
 170         size_t len;
 171 #endif
 172         int family, i;
 173         const void *addr;
 174         char *p;
 175 #if 0
 176         unsigned long v4a;
 177         unsigned char pfx;
 178 #endif
 179         char numserv[sizeof("65000")];
 180         char numaddr[sizeof("abcd:abcd:abcd:abcd:abcd:abcd:255.255.255.255")
 181                     + 1 + sizeof("4294967295")];
 182         const char *proto;
 183         lwres_uint32_t lwf = 0;
 184         lwres_context_t *lwrctx = NULL;
 185         lwres_gnbaresponse_t *by = NULL;
 186         int result = SUCCESS;
 187         int n;
 188
 189         if (sa == NULL)
 190                 ERR(ENI_NOSOCKET);
 191
 192 #ifdef LWRES_PLATFORM_HAVESALEN
 193         len = sa->sa_len;
 194         if (len != salen)
 195                 ERR(ENI_SALEN);
 196 #endif
 197
 198         family = sa->sa_family;
 199         for (i = 0; afdl[i].a_af; i++)
 200                 if (afdl[i].a_af == family) {
 201                         afd = &afdl[i];
 202                         goto found;
 203                 }
 204         ERR(ENI_FAMILY);
 205
 206  found:
 207         if (salen != afd->a_socklen)
 208                 ERR(ENI_SALEN);
 209
 210         switch (family) {
 211         case AF_INET:
 212                 port = ((const struct sockaddr_in *)sa)->sin_port;
 213                 addr = &((const struct sockaddr_in *)sa)->sin_addr.s_addr;
 214                 break;
 215
 216         case AF_INET6:
 217                 port = ((const struct sockaddr_in6 *)sa)->sin6_port;
 218                 addr = ((const struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
 219                 break;
 220
 221         default:
 222                 port = 0;
 223                 addr = NULL;
 224                 INSIST(0);
 225         }
 226         proto = (flags & NI_DGRAM) ? "udp" : "tcp";
 227
 228         if (serv == NULL || servlen == 0U) {
 229                 /*
 230                  * Caller does not want service.
 231                  */
 232         } else if ((flags & NI_NUMERICSERV) != 0 ||
 233                    (sp = getservbyport(port, proto)) == NULL) {
 234                 snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
 235                 if ((strlen(numserv) + 1) > servlen)
 236                         ERR(ENI_MEMORY);
 237                 strcpy(serv, numserv);
 238         } else {
 239                 if ((strlen(sp->s_name) + 1) > servlen)
 240                         ERR(ENI_MEMORY);
 241                 strcpy(serv, sp->s_name);
 242         }
 243
 244 #if 0
 245         switch (sa->sa_family) {
 246         case AF_INET:
 247                 v4a = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
 248                 if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
 249                         flags |= NI_NUMERICHOST;
 250                 v4a >>= IN_CLASSA_NSHIFT;
 251                 if (v4a == 0 || v4a == IN_LOOPBACKNET)
 252                         flags |= NI_NUMERICHOST;
 253                 break;
 254
 255         case AF_INET6:
 256                 pfx = ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[0];
 257                 if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
 258                         flags |= NI_NUMERICHOST;
 259                 break;
 260         }
 261 #endif
 262
 263         if (host == NULL || hostlen == 0U) {
 264                 /*
 265                  * What should we do?
 266                  */
 267         } else if (flags & NI_NUMERICHOST) {
 268                 if (lwres_net_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
 269                     == NULL)
 270                         ERR(ENI_SYSTEM);
 271 #if defined(LWRES_HAVE_SIN6_SCOPE_ID)
 272                 if (afd->a_af == AF_INET6 &&
 273                     ((const struct sockaddr_in6 *)sa)->sin6_scope_id) {
 274                         char *p = numaddr + strlen(numaddr);
 275                         const char *stringscope = NULL;
 276 #if 0
 277                         if ((flags & NI_NUMERICSCOPE) == 0) {
 278                                 /*
 279                                  * Vendors may want to add support for
 280                                  * non-numeric scope identifier.
 281                                  */
 282                                 stringscope = foo;
 283                         }
 284 #endif
 285                         if (stringscope == NULL) {
 286                                 snprintf(p, sizeof(numaddr) - (p - numaddr),
 287                                     "%%%u",
 288                                     ((const struct sockaddr_in6 *)sa)->sin6_scope_id);
 289                         } else {
 290                                 snprintf(p, sizeof(numaddr) - (p - numaddr),
 291                                     "%%%s", stringscope);
 292                         }
 293                 }
 294 #endif
 295                 if (strlen(numaddr) + 1 > hostlen)
 296                         ERR(ENI_MEMORY);
 297                 strcpy(host, numaddr);
 298         } else {
 299                 switch (family) {
 300                 case AF_INET:
 301                         lwf = LWRES_ADDRTYPE_V4;
 302                         break;
 303                 case AF_INET6:
 304                         lwf = LWRES_ADDRTYPE_V6;
 305                         break;
 306                 default:
 307                         INSIST(0);
 308                 }
 309
 310                 n = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
 311                 if (n == 0)
 312                         (void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
 313
 314                 if (n == 0)
 315                         n = lwres_getnamebyaddr(lwrctx, lwf,
 316                                                 (lwres_uint16_t)afd->a_addrlen,
 317                                                 addr, &by);
 318                 if (n == 0) {
 319                         if (flags & NI_NOFQDN) {
 320                                 p = strchr(by->realname, '.');
 321                                 if (p)
 322                                         *p = '\0';
 323                         }
 324                         if ((strlen(by->realname) + 1) > hostlen)
 325                                 ERR(ENI_MEMORY);
 326                         strcpy(host, by->realname);
 327                 } else {
 328                         if (flags & NI_NAMEREQD)
 329                                 ERR(ENI_NOHOSTNAME);
 330                         if (lwres_net_ntop(afd->a_af, addr, numaddr,
 331                                            sizeof(numaddr))
 332                             == NULL)
 333                                 ERR(ENI_NOHOSTNAME);
 334                         if ((strlen(numaddr) + 1) > hostlen)
 335                                 ERR(ENI_MEMORY);
 336                         strcpy(host, numaddr);
 337                 }
 338         }
 339         result = SUCCESS;
 340  cleanup:
 341         if (by != NULL)
 342                 lwres_gnbaresponse_free(lwrctx, &by);
 343         if (lwrctx != NULL) {
 344                 lwres_conf_clear(lwrctx);
 345                 lwres_context_destroy(&lwrctx);
 346         }
 347         return (result);
 348 }