dlls/dnsapi/ns_parse.c

   1 /*
   2  * Copyright (c) 1996,1999 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #include "config.h"
  19
  20 #ifdef HAVE_RESOLV
  21
  22 #include <sys/types.h>
  23
  24 #ifdef HAVE_NETINET_IN_H
  25 # include <netinet/in.h>
  26 #endif
  27 #ifdef HAVE_ARPA_NAMESER_H
  28 # include <arpa/nameser.h>
  29 #endif
  30
  31 #include <errno.h>
  32 #ifdef HAVE_RESOLV_H
  33 # include <resolv.h>
  34 #endif
  35 #include <string.h>
  36
  37 /* Forward. */
  38
  39 static void     setsection(ns_msg *msg, ns_sect sect);
  40
  41 /* Macros. */
  42
  43 #define RETERR(err) do { return (-1); } while (0)
  44
  45 #ifdef HAVE_NS_MSG__MSG_PTR
  46 # define NS_PTR(ns_msg) ((ns_msg)->_msg_ptr)
  47 #else
  48 # define NS_PTR(ns_msg) ((ns_msg)->_ptr)
  49 #endif
  50
  51 /* Public. */
  52
  53 static int
  54 dns_ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  55         const u_char *optr = ptr;
  56
  57         for ((void)NULL; count > 0; count--) {
  58                 int b, rdlength;
  59
  60                 b = dn_skipname(ptr, eom);
  61                 if (b < 0)
  62                         RETERR(EMSGSIZE);
  63                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  64                 if (section != ns_s_qd) {
  65                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
  66                                 RETERR(EMSGSIZE);
  67                         ptr += NS_INT32SZ/*TTL*/;
  68                         NS_GET16(rdlength, ptr);
  69                         ptr += rdlength/*RData*/;
  70                 }
  71         }
  72         if (ptr > eom)
  73                 RETERR(EMSGSIZE);
  74         return (ptr - optr);
  75 }
  76
  77 int
  78 dns_ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
  79         const u_char *eom = msg + msglen;
  80         int i;
  81
  82         memset(handle, 0x5e, sizeof *handle);
  83         handle->_msg = msg;
  84         handle->_eom = eom;
  85         if (msg + NS_INT16SZ > eom)
  86                 RETERR(EMSGSIZE);
  87         NS_GET16(handle->_id, msg);
  88         if (msg + NS_INT16SZ > eom)
  89                 RETERR(EMSGSIZE);
  90         NS_GET16(handle->_flags, msg);
  91         for (i = 0; i < ns_s_max; i++) {
  92                 if (msg + NS_INT16SZ > eom)
  93                         RETERR(EMSGSIZE);
  94                 NS_GET16(handle->_counts[i], msg);
  95         }
  96         for (i = 0; i < ns_s_max; i++)
  97                 if (handle->_counts[i] == 0)
  98                         handle->_sections[i] = NULL;
  99                 else {
 100                         int b = dns_ns_skiprr(msg, eom, (ns_sect)i,
 101                                           handle->_counts[i]);
 102
 103                         if (b < 0)
 104                                 return (-1);
 105                         handle->_sections[i] = msg;
 106                         msg += b;
 107                 }
 108         if (msg != eom)
 109                 RETERR(EMSGSIZE);
 110         setsection(handle, ns_s_max);
 111         return (0);
 112 }
 113
 114 int
 115 dns_ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 116         int b;
 117
 118         /* Make section right. */
 119         if (section < 0 || section >= ns_s_max)
 120                 RETERR(ENODEV);
 121         if (section != handle->_sect)
 122                 setsection(handle, section);
 123
 124         /* Make rrnum right. */
 125         if (rrnum == -1)
 126                 rrnum = handle->_rrnum;
 127         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 128                 RETERR(ENODEV);
 129         if (rrnum < handle->_rrnum)
 130                 setsection(handle, section);
 131         if (rrnum > handle->_rrnum) {
 132                 b = dns_ns_skiprr(NS_PTR(handle), handle->_eom, section,
 133                               rrnum - handle->_rrnum);
 134
 135                 if (b < 0)
 136                         return (-1);
 137                 NS_PTR(handle) += b;
 138                 handle->_rrnum = rrnum;
 139         }
 140
 141         /* Do the parse. */
 142         b = dn_expand(handle->_msg, handle->_eom,
 143                       NS_PTR(handle), rr->name, NS_MAXDNAME);
 144         if (b < 0)
 145                 return (-1);
 146         NS_PTR(handle) += b;
 147         if (NS_PTR(handle) + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 148                 RETERR(EMSGSIZE);
 149         NS_GET16(rr->type, NS_PTR(handle));
 150         NS_GET16(rr->rr_class, NS_PTR(handle));
 151         if (section == ns_s_qd) {
 152                 rr->ttl = 0;
 153                 rr->rdlength = 0;
 154                 rr->rdata = NULL;
 155         } else {
 156                 if (NS_PTR(handle) + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 157                         RETERR(EMSGSIZE);
 158                 NS_GET32(rr->ttl, NS_PTR(handle));
 159                 NS_GET16(rr->rdlength, NS_PTR(handle));
 160                 if (NS_PTR(handle) + rr->rdlength > handle->_eom)
 161                         RETERR(EMSGSIZE);
 162                 rr->rdata = NS_PTR(handle);
 163                 NS_PTR(handle) += rr->rdlength;
 164         }
 165         if (++handle->_rrnum > handle->_counts[(int)section])
 166                 setsection(handle, (ns_sect)((int)section + 1));
 167
 168         /* All done. */
 169         return (0);
 170 }
 171
 172 /* Private. */
 173
 174 static void
 175 setsection(ns_msg *msg, ns_sect sect) {
 176         msg->_sect = sect;
 177         if (sect == ns_s_max) {
 178                 msg->_rrnum = -1;
 179                 NS_PTR(msg) = NULL;
 180         } else {
 181                 msg->_rrnum = 0;
 182                 NS_PTR(msg) = msg->_sections[(int)sect];
 183         }
 184 }
 185
 186 #endif