mdw@git.distorted.org.uk Git - adns/blob - src/parse.c

   1 /*
   2  * parse.c
   3  * - parsing assistance functions (mainly for domains inside datagrams)
   4  */
   5 /*
   6  *  This file is
   7  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
   8  *
   9  *  It is part of adns, which is
  10  *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
  11  *    Copyright (C) 1999 Tony Finch <dot@dotat.at>
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; either version 2, or (at your option)
  16  *  any later version.
  17  *
  18  *  This program is distributed in the hope that it will be useful,
  19  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *  GNU General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License
  24  *  along with this program; if not, write to the Free Software Foundation,
  25  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26  */
  27
  28 #include "internal.h"
  29
  30 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) {
  31   char qbuf[10];
  32   int i, ch;
  33
  34   while (len) {
  35     qbuf[0]= 0;
  36     for (i=0; i<len; i++) {
  37       ch= buf[i];
  38       if (ch <= ' ' || ch >= 127) {
  39         sprintf(qbuf,"\\%03o",ch);
  40         break;
  41       } else if (!ctype_domainunquoted(ch)) {
  42         sprintf(qbuf,"\\%c",ch);
  43         break;
  44       }
  45     }
  46     if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf)))
  47       return 0;
  48     if (i<len) i++;
  49     buf+= i;
  50     len-= i;
  51   }
  52   return 1;
  53 }
  54
  55 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
  56                            int serv, adns_query qu,
  57                            const byte *dgram, int dglen, int max,
  58                            int dmbegin, int *dmend_rlater) {
  59   fls->ads= ads;
  60   fls->qu= qu;
  61   fls->serv= serv;
  62   fls->dgram= dgram;
  63   fls->dglen= dglen;
  64   fls->max= max;
  65   fls->cbyte= dmbegin;
  66   fls->namelen= 0;
  67   fls->dmend_r= dmend_rlater;
  68 }
  69
  70 adns_status adns__findlabel_next(findlabel_state *fls,
  71                                  int *lablen_r, int *labstart_r) {
  72   int lablen, jumped, jumpto;
  73   const char *dgram;
  74
  75   jumped= 0;
  76   dgram= fls->dgram;
  77   for (;;) {
  78     if (fls->cbyte >= fls->dglen) goto x_truncated;
  79     if (fls->cbyte >= fls->max) goto x_badresponse;
  80     GET_B(fls->cbyte,lablen);
  81     if (!(lablen & 0x0c0)) break;
  82     if ((lablen & 0x0c0) != 0x0c0) return adns_s_unknownformat;
  83     if (jumped++) {
  84       adns__diag(fls->ads,fls->serv,fls->qu,"compressed datagram contains loop");
  85       return adns_s_invalidresponse;
  86     }
  87     if (fls->cbyte >= fls->dglen) goto x_truncated;
  88     if (fls->cbyte >= fls->max) goto x_badresponse;
  89     GET_B(fls->cbyte,jumpto);
  90     jumpto |= (lablen&0x3f)<<8;
  91     if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
  92     fls->cbyte= jumpto;
  93     fls->dmend_r= 0; fls->max= fls->dglen+1;
  94   }
  95   if (labstart_r) *labstart_r= fls->cbyte;
  96   if (lablen) {
  97     if (fls->namelen) fls->namelen++;
  98     fls->namelen+= lablen;
  99     if (fls->namelen > DNS_MAXDOMAIN) return adns_s_answerdomaintoolong;
 100     fls->cbyte+= lablen;
 101     if (fls->cbyte > fls->dglen) goto x_truncated;
 102     if (fls->cbyte > fls->max) goto x_badresponse;
 103   } else {
 104     if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
 105   }
 106   *lablen_r= lablen;
 107 /*if (labstart_r) fprintf(stderr,"label %d >%.*s<\n",lablen,lablen,fls->dgram+*labstart_r);*/
 108   return adns_s_ok;
 109
 110  x_truncated:
 111   *lablen_r= -1;
 112   return adns_s_ok;
 113
 114  x_badresponse:
 115   adns__diag(fls->ads,fls->serv,fls->qu,"label in domain runs beyond end of domain");
 116   return adns_s_invalidresponse;
 117 }
 118
 119 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
 120                                vbuf *vb, adns_queryflags flags,
 121                                const byte *dgram, int dglen, int *cbyte_io, int max) {
 122   findlabel_state fls;
 123
 124   adns__findlabel_start(&fls,ads, serv,qu, dgram,dglen,max, *cbyte_io,cbyte_io);
 125   vb->used= 0;
 126   return adns__parse_domain_more(&fls,ads,qu, vb,flags,dgram);
 127 }
 128
 129 adns_status adns__parse_domain_more(findlabel_state *fls, adns_state ads,
 130                                     adns_query qu, vbuf *vb, parsedomain_flags flags,
 131                                     const byte *dgram) {
 132   int lablen, labstart, i, ch, first;
 133   adns_status st;
 134
 135   first= 1;
 136   for (;;) {
 137     st= adns__findlabel_next(fls,&lablen,&labstart);
 138     if (st) return st;
 139     if (lablen<0) { vb->used=0; return adns_s_ok; }
 140     if (!lablen) break;
 141     if (first) {
 142       first= 0;
 143     } else {
 144       if (!adns__vbuf_append(vb,".",1)) return adns_s_nomemory;
 145     }
 146     if (flags & pdf_quoteok) {
 147       if (!vbuf__append_quoted1035(vb,dgram+labstart,lablen))
 148         return adns_s_nomemory;
 149     } else {
 150       ch= dgram[labstart];
 151       if (!ctype_alpha(ch) && !ctype_digit(ch)) return adns_s_answerdomaininvalid;
 152       for (i= labstart+1; i<labstart+lablen; i++) {
 153         ch= dgram[i];
 154         if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch))
 155           return adns_s_answerdomaininvalid;
 156       }
 157       if (!adns__vbuf_append(vb,dgram+labstart,lablen))
 158         return adns_s_nomemory;
 159     }
 160   }
 161   if (!adns__vbuf_append(vb,"",1)) return adns_s_nomemory;
 162   return adns_s_ok;
 163 }
 164
 165 adns_status adns__findrr_anychk(adns_query qu, int serv,
 166                                 const byte *dgram, int dglen, int *cbyte_io,
 167                                 int *type_r, int *class_r, unsigned long *ttl_r,
 168                                 int *rdlen_r, int *rdstart_r,
 169                                 const byte *eo_dgram, int eo_dglen, int eo_cbyte,
 170                                 int *eo_matched_r) {
 171   findlabel_state fls, eo_fls;
 172   int cbyte;
 173
 174   int tmp, rdlen, mismatch;
 175   unsigned long ttl;
 176   int lablen, labstart, ch;
 177   int eo_lablen, eo_labstart, eo_ch;
 178   adns_status st;
 179
 180   cbyte= *cbyte_io;
 181
 182   adns__findlabel_start(&fls,qu->ads, serv,qu, dgram,dglen,dglen,cbyte,&cbyte);
 183   if (eo_dgram) {
 184     adns__findlabel_start(&eo_fls,qu->ads, -1,0, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0);
 185     mismatch= 0;
 186   } else {
 187     mismatch= 1;
 188   }
 189
 190   for (;;) {
 191     st= adns__findlabel_next(&fls,&lablen,&labstart);
 192     if (st) return st;
 193     if (lablen<0) goto x_truncated;
 194
 195     if (!mismatch) {
 196       st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart);
 197       assert(!st); assert(eo_lablen>=0);
 198       if (lablen != eo_lablen) mismatch= 1;
 199       while (!mismatch && eo_lablen-- > 0) {
 200         ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32;
 201         eo_ch= eo_dgram[eo_labstart++]; if (ctype_alpha(eo_ch)) eo_ch &= ~32;
 202         if (ch != eo_ch) mismatch= 1;
 203       }
 204     }
 205     if (!lablen) break;
 206   }
 207   if (eo_matched_r) *eo_matched_r= !mismatch;
 208
 209   if (cbyte+10>dglen) goto x_truncated;
 210   GET_W(cbyte,tmp); *type_r= tmp;
 211   GET_W(cbyte,tmp); *class_r= tmp;
 212
 213   GET_L(cbyte,ttl);
 214   if (ttl > MAXTTLBELIEVE) ttl= MAXTTLBELIEVE;
 215   *ttl_r= ttl;
 216
 217   GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= rdlen;
 218   if (rdstart_r) *rdstart_r= cbyte;
 219   cbyte+= rdlen;
 220   if (cbyte>dglen) goto x_truncated;
 221   *cbyte_io= cbyte;
 222   return adns_s_ok;
 223
 224  x_truncated:
 225   *type_r= -1;
 226   return 0;
 227 }
 228
 229 adns_status adns__findrr(adns_query qu, int serv,
 230                          const byte *dgram, int dglen, int *cbyte_io,
 231                          int *type_r, int *class_r, unsigned long *ttl_r,
 232                          int *rdlen_r, int *rdstart_r,
 233                          int *ownermatchedquery_r) {
 234   if (!ownermatchedquery_r) {
 235     return adns__findrr_anychk(qu,serv,
 236                                dgram,dglen,cbyte_io,
 237                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 238                                0,0,0, 0);
 239   } else if (!qu->cname_dgram) {
 240     return adns__findrr_anychk(qu,serv,
 241                                dgram,dglen,cbyte_io,
 242                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 243                                qu->query_dgram,qu->query_dglen,DNS_HDRSIZE,
 244                                ownermatchedquery_r);
 245   } else {
 246     return adns__findrr_anychk(qu,serv,
 247                                dgram,dglen,cbyte_io,
 248                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 249                                qu->cname_dgram,qu->cname_dglen,qu->cname_begin,
 250                                ownermatchedquery_r);
 251   }
 252 }