usr/src/lib/libresolv2/common/resolv/res_mkquery.c

   1 /*
   2  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6
   7 /*
   8  * Portions Copyright (C) 2004, 2005, 2008  Internet Systems Consortium, Inc. ("ISC")
   9  * Portions Copyright (C) 1996, 1997, 1988, 1999, 2001, 2003  Internet Software Consortium.
  10  *
  11  * Permission to use, copy, modify, and/or distribute this software for any
  12  * purpose with or without fee is hereby granted, provided that the above
  13  * copyright notice and this permission notice appear in all copies.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  16  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  17  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  18  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  19  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  20  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  21  * PERFORMANCE OF THIS SOFTWARE.
  22  */
  23
  24 /*
  25  * Copyright (c) 1985, 1993
  26  *    The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 /*
  58  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  59  *
  60  * Permission to use, copy, modify, and distribute this software for any
  61  * purpose with or without fee is hereby granted, provided that the above
  62  * copyright notice and this permission notice appear in all copies, and that
  63  * the name of Digital Equipment Corporation not be used in advertising or
  64  * publicity pertaining to distribution of the document or software without
  65  * specific, written prior permission.
  66  *
  67  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  68  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  69  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  70  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  71  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  72  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  73  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  74  * SOFTWARE.
  75  */
  76
  77 #if defined(LIBC_SCCS) && !defined(lint)
  78 static const char sccsid[] = "@(#)res_mkquery.c 8.1 (Berkeley) 6/4/93";
  79 static const char rcsid[] = "$Id: res_mkquery.c,v 1.10 2008/12/11 09:59:00 marka Exp $";
  80 #endif /* LIBC_SCCS and not lint */
  81
  82 #include "port_before.h"
  83 #include <sys/types.h>
  84 #include <sys/param.h>
  85 #include <netinet/in.h>
  86 #include <arpa/nameser.h>
  87
  88 #ifdef SUNW_CONFCHECK
  89 #include <sys/socket.h>
  90 #include <errno.h>
  91 #include <sys/stat.h>
  92 #endif /* SUNW_CONFCHECK */
  93
  94
  95 #include <netdb.h>
  96 #include <resolv.h>
  97 #include <stdio.h>
  98 #include <string.h>
  99 #include "port_after.h"
 100
 101 /* Options.  Leave them on. */
 102 #define DEBUG
 103
 104 extern const char *_res_opcodes[];
 105
 106 #ifdef SUNW_CONFCHECK
 107 static int      _confcheck(res_state statp);
 108 #endif /* SUNW_CONFCHECK */
 109
 110
 111 /*%
 112  * Form all types of queries.
 113  * Returns the size of the result or -1.
 114  */
 115 int
 116 res_nmkquery(res_state statp,
 117              int op,                    /*!< opcode of query  */
 118              const char *dname,         /*!< domain name  */
 119              int class, int type,       /*!< class and type of query  */
 120              const u_char *data,        /*!< resource record data  */
 121              int datalen,               /*!< length of data  */
 122              const u_char *newrr_in,    /*!< new rr for modify or append  */
 123              u_char *buf,               /*!< buffer to put query  */
 124              int buflen)                /*!< size of buffer  */
 125 {
 126         register HEADER *hp;
 127         register u_char *cp, *ep;
 128         register int n;
 129         u_char *dnptrs[20], **dpp, **lastdnptr;
 130
 131         UNUSED(newrr_in);
 132
 133 #ifdef DEBUG
 134         if (statp->options & RES_DEBUG)
 135                 printf(";; res_nmkquery(%s, %s, %s, %s)\n",
 136                        _res_opcodes[op], dname, p_class(class), p_type(type));
 137 #endif
 138
 139 #ifdef SUNW_CONFCHECK
 140         /*
 141          * 1247019, 1265838, and 4034368: Check to see if we can
 142          * bailout quickly.
 143          */
 144         if (_confcheck(statp) == -1) {
 145                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 146                 return(-1);
 147         }
 148 #endif /* SUNW_CONFCHECK */
 149
 150         /*
 151          * Initialize header fields.
 152          */
 153         if ((buf == NULL) || (buflen < HFIXEDSZ))
 154                 return (-1);
 155         memset(buf, 0, HFIXEDSZ);
 156         hp = (HEADER *) buf;
 157         statp->id = res_nrandomid(statp);
 158         hp->id = htons(statp->id);
 159         hp->opcode = op;
 160         hp->rd = (statp->options & RES_RECURSE) != 0U;
 161         hp->rcode = NOERROR;
 162         cp = buf + HFIXEDSZ;
 163         ep = buf + buflen;
 164         dpp = dnptrs;
 165         *dpp++ = buf;
 166         *dpp++ = NULL;
 167         lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
 168         /*
 169          * perform opcode specific processing
 170          */
 171         switch (op) {
 172         case QUERY:     /*FALLTHROUGH*/
 173         case NS_NOTIFY_OP:
 174                 if (ep - cp < QFIXEDSZ)
 175                         return (-1);
 176                 if ((n = dn_comp(dname, cp, ep - cp - QFIXEDSZ, dnptrs,
 177                     lastdnptr)) < 0)
 178                         return (-1);
 179                 cp += n;
 180                 ns_put16(type, cp);
 181                 cp += INT16SZ;
 182                 ns_put16(class, cp);
 183                 cp += INT16SZ;
 184                 hp->qdcount = htons(1);
 185                 if (op == QUERY || data == NULL)
 186                         break;
 187                 /*
 188                  * Make an additional record for completion domain.
 189                  */
 190                 if ((ep - cp) < RRFIXEDSZ)
 191                         return (-1);
 192                 n = dn_comp((const char *)data, cp, ep - cp - RRFIXEDSZ,
 193                             dnptrs, lastdnptr);
 194                 if (n < 0)
 195                         return (-1);
 196                 cp += n;
 197                 ns_put16(T_NULL, cp);
 198                 cp += INT16SZ;
 199                 ns_put16(class, cp);
 200                 cp += INT16SZ;
 201                 ns_put32(0, cp);
 202                 cp += INT32SZ;
 203                 ns_put16(0, cp);
 204                 cp += INT16SZ;
 205                 hp->arcount = htons(1);
 206                 break;
 207
 208         case IQUERY:
 209                 /*
 210                  * Initialize answer section
 211                  */
 212                 if (ep - cp < 1 + RRFIXEDSZ + datalen)
 213                         return (-1);
 214                 *cp++ = '\0';   /*%< no domain name */
 215                 ns_put16(type, cp);
 216                 cp += INT16SZ;
 217                 ns_put16(class, cp);
 218                 cp += INT16SZ;
 219                 ns_put32(0, cp);
 220                 cp += INT32SZ;
 221                 ns_put16(datalen, cp);
 222                 cp += INT16SZ;
 223                 if (datalen) {
 224                         memcpy(cp, data, datalen);
 225                         cp += datalen;
 226                 }
 227                 hp->ancount = htons(1);
 228                 break;
 229
 230         default:
 231                 return (-1);
 232         }
 233         return (cp - buf);
 234 }
 235
 236 #ifdef RES_USE_EDNS0
 237 /* attach OPT pseudo-RR, as documented in RFC2671 (EDNS0). */
 238
 239 int
 240 res_nopt(res_state statp,
 241          int n0,                /*%< current offset in buffer */
 242          u_char *buf,           /*%< buffer to put query */
 243          int buflen,            /*%< size of buffer */
 244          int anslen)            /*%< UDP answer buffer size */
 245 {
 246         register HEADER *hp;
 247         register u_char *cp, *ep;
 248         u_int16_t flags = 0;
 249
 250 #ifdef DEBUG
 251         if ((statp->options & RES_DEBUG) != 0U)
 252                 printf(";; res_nopt()\n");
 253 #endif
 254
 255         hp = (HEADER *) buf;
 256         cp = buf + n0;
 257         ep = buf + buflen;
 258
 259         if ((ep - cp) < 1 + RRFIXEDSZ)
 260                 return (-1);
 261
 262         *cp++ = 0;                              /*%< "." */
 263         ns_put16(ns_t_opt, cp);                 /*%< TYPE */
 264         cp += INT16SZ;
 265         ns_put16(anslen & 0xffff, cp);          /*%< CLASS = UDP payload size */
 266         cp += INT16SZ;
 267         *cp++ = NOERROR;                        /*%< extended RCODE */
 268         *cp++ = 0;                              /*%< EDNS version */
 269
 270         if (statp->options & RES_USE_DNSSEC) {
 271 #ifdef DEBUG
 272                 if (statp->options & RES_DEBUG)
 273                         printf(";; res_opt()... ENDS0 DNSSEC\n");
 274 #endif
 275                 flags |= NS_OPT_DNSSEC_OK;
 276         }
 277         ns_put16(flags, cp);
 278         cp += INT16SZ;
 279
 280         ns_put16(0U, cp);                       /*%< RDLEN */
 281         cp += INT16SZ;
 282
 283         hp->arcount = htons(ntohs(hp->arcount) + 1);
 284
 285         return (cp - buf);
 286 }
 287
 288 /*
 289  * Construct variable data (RDATA) block for OPT psuedo-RR, append it
 290  * to the buffer, then update the RDLEN field (previously set to zero by
 291  * res_nopt()) with the new RDATA length.
 292  */
 293 int
 294 res_nopt_rdata(res_state statp,
 295           int n0,               /*%< current offset in buffer */
 296           u_char *buf,          /*%< buffer to put query */
 297           int buflen,           /*%< size of buffer */
 298           u_char *rdata,        /*%< ptr to start of opt rdata */
 299           u_short code,         /*%< OPTION-CODE */
 300           u_short len,          /*%< OPTION-LENGTH */
 301           u_char *data)         /*%< OPTION_DATA */
 302 {
 303         register u_char *cp, *ep;
 304
 305 #ifdef DEBUG
 306         if ((statp->options & RES_DEBUG) != 0U)
 307                 printf(";; res_nopt_rdata()\n");
 308 #endif
 309
 310         cp = buf + n0;
 311         ep = buf + buflen;
 312
 313         if ((ep - cp) < (4 + len))
 314                 return (-1);
 315
 316         if (rdata < (buf + 2) || rdata >= ep)
 317                 return (-1);
 318
 319         ns_put16(code, cp);
 320         cp += INT16SZ;
 321
 322         ns_put16(len, cp);
 323         cp += INT16SZ;
 324
 325         memcpy(cp, data, len);
 326         cp += len;
 327
 328         len = cp - rdata;
 329         ns_put16(len, rdata - 2);       /* Update RDLEN field */
 330
 331         return (cp - buf);
 332 }
 333 #endif
 334
 335 #ifdef SUNW_CONFCHECK
 336
 337 /*
 338  * Time out quickly if there is no /etc/resolv.conf and a TCP connection
 339  * to the local DNS server fails.
 340  */
 341 static int _confcheck(res_state statp)
 342 {
 343         int ns;
 344         struct stat rc_stat;
 345         struct sockaddr_in ns_sin;
 346
 347         /* First, we check to see if /etc/resolv.conf exists.
 348          * If it doesn't, then it is likely that the localhost is
 349          * the nameserver.
 350          */
 351         if (stat(_PATH_RESCONF, &rc_stat) == -1 && errno == ENOENT) {
 352
 353                 /* Next, we check to see if _res.nsaddr is set to loopback.
 354                  * If it isn't, it has been altered by the application
 355                  * explicitly and we then want to bail with success.
 356                  */
 357                 if (statp->nsaddr.sin_addr.S_un.S_addr ==
 358                                 htonl(INADDR_LOOPBACK)) {
 359
 360                         /* Lastly, we try to connect to the TCP port of the
 361                          * nameserver.  If this fails, then we know that
 362                          * DNS is misconfigured and we can quickly exit.
 363                          */
 364                         ns = socket(AF_INET, SOCK_STREAM, 0);
 365                         IN_SET_LOOPBACK_ADDR(&ns_sin);
 366                         ns_sin.sin_port = htons(NAMESERVER_PORT);
 367                         if (connect(ns, (struct sockaddr *) &ns_sin,
 368                                     sizeof ns_sin) == -1) {
 369                                 close(ns);
 370                                 return(-1);
 371                         }
 372                         else {
 373                                 close(ns);
 374
 375                                 return(0);
 376                         }
 377                 }
 378
 379                 return(0);
 380         }
 381
 382         return (0);
 383 }
 384 #endif /* SUNW_CONFCHECK */
 385
 386 /*! \file */