resolv/res_mkquery.c

   1 /*
   2  * Copyright (c) 1985, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  */
  49
  50 /*
  51  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  52  *
  53  * Permission to use, copy, modify, and distribute this software for any
  54  * purpose with or without fee is hereby granted, provided that the above
  55  * copyright notice and this permission notice appear in all copies.
  56  *
  57  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  58  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  59  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  60  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  61  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  62  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  63  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  64  * SOFTWARE.
  65  */
  66
  67 #include <sys/types.h>
  68 #include <sys/param.h>
  69 #include <netinet/in.h>
  70 #include <arpa/nameser.h>
  71 #include <netdb.h>
  72 #include <resolv/resolv-internal.h>
  73 #include <stdio.h>
  74 #include <string.h>
  75 #include <sys/time.h>
  76
  77 /* Options.  Leave them on. */
  78 /* #define DEBUG */
  79
  80 #include <hp-timing.h>
  81 #include <stdint.h>
  82 #if HP_TIMING_AVAIL
  83 # define RANDOM_BITS(Var) { uint64_t v64; HP_TIMING_NOW (v64); Var = v64; }
  84 #endif
  85
  86 /*
  87  * Form all types of queries.
  88  * Returns the size of the result or -1.
  89  */
  90 int
  91 res_nmkquery(res_state statp,
  92              int op,                    /* opcode of query */
  93              const char *dname,         /* domain name */
  94              int class, int type,       /* class and type of query */
  95              const u_char *data,        /* resource record data */
  96              int datalen,               /* length of data */
  97              const u_char *newrr_in,    /* new rr for modify or append */
  98              u_char *buf,               /* buffer to put query */
  99              int buflen)                /* size of buffer */
 100 {
 101         HEADER *hp;
 102         u_char *cp;
 103         int n;
 104         u_char *dnptrs[20], **dpp, **lastdnptr;
 105
 106         if (class < 0 || class > 65535
 107             || type < 0 || type > 65535)
 108           return -1;
 109
 110 #ifdef DEBUG
 111         if (statp->options & RES_DEBUG)
 112                 printf(";; res_nmkquery(%s, %s, %s, %s)\n",
 113                        _res_opcodes[op], dname, p_class(class), p_type(type));
 114 #endif
 115         /*
 116          * Initialize header fields.
 117          */
 118         if ((buf == NULL) || (buflen < HFIXEDSZ))
 119                 return (-1);
 120         memset(buf, 0, HFIXEDSZ);
 121         hp = (HEADER *) buf;
 122         /* We randomize the IDs every time.  The old code just
 123            incremented by one after the initial randomization which
 124            still predictable if the application does multiple
 125            requests.  */
 126         int randombits;
 127         do
 128           {
 129 #ifdef RANDOM_BITS
 130             RANDOM_BITS (randombits);
 131 #else
 132             struct timeval tv;
 133             __gettimeofday (&tv, NULL);
 134             randombits = (tv.tv_sec << 8) ^ tv.tv_usec;
 135 #endif
 136           }
 137         while ((randombits & 0xffff) == 0);
 138         statp->id = (statp->id + randombits) & 0xffff;
 139         hp->id = statp->id;
 140         hp->opcode = op;
 141         hp->rd = (statp->options & RES_RECURSE) != 0;
 142         hp->rcode = NOERROR;
 143         cp = buf + HFIXEDSZ;
 144         buflen -= HFIXEDSZ;
 145         dpp = dnptrs;
 146         *dpp++ = buf;
 147         *dpp++ = NULL;
 148         lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
 149         /*
 150          * perform opcode specific processing
 151          */
 152         switch (op) {
 153         case NS_NOTIFY_OP:
 154                 if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0)
 155                         return (-1);
 156                 goto compose;
 157
 158         case QUERY:
 159                 if ((buflen -= QFIXEDSZ) < 0)
 160                         return (-1);
 161         compose:
 162                 n = ns_name_compress(dname, cp, buflen,
 163                                      (const u_char **) dnptrs,
 164                                      (const u_char **) lastdnptr);
 165                 if (n < 0)
 166                         return (-1);
 167                 cp += n;
 168                 buflen -= n;
 169                 NS_PUT16 (type, cp);
 170                 NS_PUT16 (class, cp);
 171                 hp->qdcount = htons(1);
 172                 if (op == QUERY || data == NULL)
 173                         break;
 174                 /*
 175                  * Make an additional record for completion domain.
 176                  */
 177                 n = ns_name_compress((char *)data, cp, buflen,
 178                                      (const u_char **) dnptrs,
 179                                      (const u_char **) lastdnptr);
 180                 if (__glibc_unlikely (n < 0))
 181                         return (-1);
 182                 cp += n;
 183                 buflen -= n;
 184                 NS_PUT16 (T_NULL, cp);
 185                 NS_PUT16 (class, cp);
 186                 NS_PUT32 (0, cp);
 187                 NS_PUT16 (0, cp);
 188                 hp->arcount = htons(1);
 189                 break;
 190
 191         default:
 192                 return (-1);
 193         }
 194         return (cp - buf);
 195 }
 196 libresolv_hidden_def (res_nmkquery)
 197
 198
 199 /* attach OPT pseudo-RR, as documented in RFC2671 (EDNS0). */
 200 #ifndef T_OPT
 201 #define T_OPT   41
 202 #endif
 203
 204 int
 205 __res_nopt(res_state statp,
 206            int n0,                /* current offset in buffer */
 207            u_char *buf,           /* buffer to put query */
 208            int buflen,            /* size of buffer */
 209            int anslen)            /* UDP answer buffer size */
 210 {
 211         u_int16_t flags = 0;
 212
 213 #ifdef DEBUG
 214         if ((statp->options & RES_DEBUG) != 0U)
 215                 printf(";; res_nopt()\n");
 216 #endif
 217
 218         HEADER *hp = (HEADER *) buf;
 219         u_char *cp = buf + n0;
 220         u_char *ep = buf + buflen;
 221
 222         if ((ep - cp) < 1 + RRFIXEDSZ)
 223                 return -1;
 224
 225         *cp++ = 0;      /* "." */
 226
 227         NS_PUT16(T_OPT, cp);    /* TYPE */
 228
 229         /* Lowering the advertised buffer size based on the actual
 230            answer buffer size is desirable because the server will
 231            minimize the reply to fit into the UDP packet (and A
 232            non-minimal response might not fit the buffer).
 233
 234            The RESOLV_EDNS_BUFFER_SIZE limit could still result in TCP
 235            fallback and a non-minimal response which has to be
 236            hard-truncated in the stub resolver, but this is price to
 237            pay for avoiding fragmentation.  (This issue does not
 238            affect the nss_dns functions because they use the stub
 239            resolver in such a way that it allocates a properly sized
 240            response buffer.)  */
 241         {
 242           uint16_t buffer_size;
 243           if (anslen < 512)
 244             buffer_size = 512;
 245           else if (anslen > RESOLV_EDNS_BUFFER_SIZE)
 246             buffer_size = RESOLV_EDNS_BUFFER_SIZE;
 247           else
 248             buffer_size = anslen;
 249           NS_PUT16 (buffer_size, cp);
 250         }
 251
 252         *cp++ = NOERROR;        /* extended RCODE */
 253         *cp++ = 0;              /* EDNS version */
 254
 255         if (statp->options & RES_USE_DNSSEC) {
 256 #ifdef DEBUG
 257                 if (statp->options & RES_DEBUG)
 258                         printf(";; res_opt()... ENDS0 DNSSEC\n");
 259 #endif
 260                 flags |= NS_OPT_DNSSEC_OK;
 261         }
 262
 263         NS_PUT16(flags, cp);
 264         NS_PUT16(0, cp);        /* RDLEN */
 265         hp->arcount = htons(ntohs(hp->arcount) + 1);
 266
 267         return cp - buf;
 268 }