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 #include "windef.h"
  38
  39 /* Forward. */
  40
  41 static void     setsection(ns_msg *msg, ns_sect sect);
  42
  43 /* Macros. */
  44
  45 #define RETERR(err) do { return (-1); } while (0)
  46
  47 #ifdef HAVE_NS_MSG__MSG_PTR
  48 # define NS_PTR(ns_msg) ((ns_msg)->_msg_ptr)
  49 #else
  50 # define NS_PTR(ns_msg) ((ns_msg)->_ptr)
  51 #endif
  52
  53 #define DNS_NS_GET16(s, cp) do { \
  54     register const u_char *t_cp = (cp); \
  55     (s) = ((WORD)t_cp[0] << 8) \
  56         | ((WORD)t_cp[1]) \
  57         ; \
  58     (cp) += NS_INT16SZ; \
  59 } while (0)
  60
  61 #define DNS_NS_GET32(l, cp) do { \
  62     register const u_char *t_cp = (cp); \
  63     (l) = ((DWORD)t_cp[0] << 24) \
  64         | ((DWORD)t_cp[1] << 16) \
  65         | ((DWORD)t_cp[2] << 8) \
  66         | ((DWORD)t_cp[3]) \
  67         ; \
  68     (cp) += NS_INT32SZ; \
  69 } while (0)
  70
  71 /* Public. */
  72
  73 static int
  74 dns_ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
  75         const u_char *optr = ptr;
  76
  77         while (count-- > 0) {
  78                 int b, rdlength;
  79
  80                 b = dn_skipname(ptr, eom);
  81                 if (b < 0)
  82                         RETERR(EMSGSIZE);
  83                 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
  84                 if (section != ns_s_qd) {
  85                         if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
  86                                 RETERR(EMSGSIZE);
  87                         ptr += NS_INT32SZ/*TTL*/;
  88                         DNS_NS_GET16(rdlength, ptr);
  89                         ptr += rdlength/*RData*/;
  90                 }
  91         }
  92         if (ptr > eom)
  93                 RETERR(EMSGSIZE);
  94         return (ptr - optr);
  95 }
  96
  97 int
  98 dns_ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
  99         const u_char *eom = msg + msglen;
 100         int i;
 101
 102         memset(handle, 0x5e, sizeof *handle);
 103         handle->_msg = msg;
 104         handle->_eom = eom;
 105         if (msg + NS_INT16SZ > eom)
 106                 RETERR(EMSGSIZE);
 107         DNS_NS_GET16(handle->_id, msg);
 108         if (msg + NS_INT16SZ > eom)
 109                 RETERR(EMSGSIZE);
 110         DNS_NS_GET16(handle->_flags, msg);
 111         for (i = 0; i < ns_s_max; i++) {
 112                 if (msg + NS_INT16SZ > eom)
 113                         RETERR(EMSGSIZE);
 114                 DNS_NS_GET16(handle->_counts[i], msg);
 115         }
 116         for (i = 0; i < ns_s_max; i++)
 117                 if (handle->_counts[i] == 0)
 118                         handle->_sections[i] = NULL;
 119                 else {
 120                         int b = dns_ns_skiprr(msg, eom, (ns_sect)i,
 121                                           handle->_counts[i]);
 122
 123                         if (b < 0)
 124                                 return (-1);
 125                         handle->_sections[i] = msg;
 126                         msg += b;
 127                 }
 128         if (msg != eom)
 129                 RETERR(EMSGSIZE);
 130         setsection(handle, ns_s_max);
 131         return (0);
 132 }
 133
 134 int
 135 dns_ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
 136         int b;
 137
 138         /* Make section right. */
 139         if (section >= ns_s_max)
 140                 RETERR(ENODEV);
 141         if (section != handle->_sect)
 142                 setsection(handle, section);
 143
 144         /* Make rrnum right. */
 145         if (rrnum == -1)
 146                 rrnum = handle->_rrnum;
 147         if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
 148                 RETERR(ENODEV);
 149         if (rrnum < handle->_rrnum)
 150                 setsection(handle, section);
 151         if (rrnum > handle->_rrnum) {
 152                 b = dns_ns_skiprr(NS_PTR(handle), handle->_eom, section,
 153                               rrnum - handle->_rrnum);
 154
 155                 if (b < 0)
 156                         return (-1);
 157                 NS_PTR(handle) += b;
 158                 handle->_rrnum = rrnum;
 159         }
 160
 161         /* Do the parse. */
 162         b = dn_expand(handle->_msg, handle->_eom,
 163                       NS_PTR(handle), rr->name, NS_MAXDNAME);
 164         if (b < 0)
 165                 return (-1);
 166         NS_PTR(handle) += b;
 167         if (NS_PTR(handle) + NS_INT16SZ + NS_INT16SZ > handle->_eom)
 168                 RETERR(EMSGSIZE);
 169         DNS_NS_GET16(rr->type, NS_PTR(handle));
 170         DNS_NS_GET16(rr->rr_class, NS_PTR(handle));
 171         if (section == ns_s_qd) {
 172                 rr->ttl = 0;
 173                 rr->rdlength = 0;
 174                 rr->rdata = NULL;
 175         } else {
 176                 if (NS_PTR(handle) + NS_INT32SZ + NS_INT16SZ > handle->_eom)
 177                         RETERR(EMSGSIZE);
 178                 DNS_NS_GET32(rr->ttl, NS_PTR(handle));
 179                 DNS_NS_GET16(rr->rdlength, NS_PTR(handle));
 180                 if (NS_PTR(handle) + rr->rdlength > handle->_eom)
 181                         RETERR(EMSGSIZE);
 182                 rr->rdata = NS_PTR(handle);
 183                 NS_PTR(handle) += rr->rdlength;
 184         }
 185         if (++handle->_rrnum > handle->_counts[(int)section])
 186                 setsection(handle, (ns_sect)((int)section + 1));
 187
 188         /* All done. */
 189         return (0);
 190 }
 191
 192 /* Private. */
 193
 194 static void
 195 setsection(ns_msg *msg, ns_sect sect) {
 196         msg->_sect = sect;
 197         if (sect == ns_s_max) {
 198                 msg->_rrnum = -1;
 199                 NS_PTR(msg) = NULL;
 200         } else {
 201                 msg->_rrnum = 0;
 202                 NS_PTR(msg) = msg->_sections[(int)sect];
 203         }
 204 }
 205
 206 #endif