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) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
   8  *
   9  *  It is part of adns, which is
  10  *    Copyright (C) 1997-1999 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 == '"' || ch == '(' || ch == ')' ||
  39           ch == '@' || ch == ';' || ch == '$' || ch == '\\') {
  40         sprintf(qbuf,"\\%c",ch);
  41         break;
  42       } else if (ch <= ' ' || ch >= 127) {
  43         sprintf(qbuf,"\\%03o",ch);
  44         break;
  45       }
  46     }
  47     if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf)))
  48       return 0;
  49     if (i<len) i++;
  50     buf+= i;
  51     len-= i;
  52   }
  53   return 1;
  54 }
  55
  56 void adns__findlabel_start(findlabel_state *fls, adns_state ads,
  57                            int serv, adns_query qu,
  58                            const byte *dgram, int dglen, int max,
  59                            int dmbegin, int *dmend_rlater) {
  60   fls->ads= ads;
  61   fls->qu= qu;
  62   fls->serv= serv;
  63   fls->dgram= dgram;
  64   fls->dglen= dglen;
  65   fls->max= max;
  66   fls->cbyte= dmbegin;
  67   fls->namelen= 0;
  68   fls->dmend_r= dmend_rlater;
  69 }
  70
  71 adns_status adns__findlabel_next(findlabel_state *fls,
  72                                  int *lablen_r, int *labstart_r) {
  73   int lablen, jumped, jumpto;
  74   const char *dgram;
  75
  76   jumped= 0;
  77   dgram= fls->dgram;
  78   for (;;) {
  79     if (fls->cbyte >= fls->dglen) goto x_truncated;
  80     if (fls->cbyte >= fls->max) goto x_badresponse;
  81     GET_B(fls->cbyte,lablen);
  82     if (!(lablen & 0x0c0)) break;
  83     if ((lablen & 0x0c0) != 0x0c0) return adns_s_unknownformat;
  84     if (jumped++) {
  85       adns__diag(fls->ads,fls->serv,fls->qu,"compressed datagram contains loop");
  86       return adns_s_invalidresponse;
  87     }
  88     if (fls->cbyte >= fls->dglen) goto x_truncated;
  89     if (fls->cbyte >= fls->max) goto x_badresponse;
  90     GET_B(fls->cbyte,jumpto);
  91     jumpto |= (lablen&0x3f)<<8;
  92     if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
  93     fls->cbyte= jumpto;
  94     fls->dmend_r= 0; fls->max= fls->dglen+1;
  95   }
  96   if (labstart_r) *labstart_r= fls->cbyte;
  97   if (lablen) {
  98     if (fls->namelen) fls->namelen++;
  99     fls->namelen+= lablen;
 100     if (fls->namelen > DNS_MAXDOMAIN) return adns_s_answerdomaintoolong;
 101     fls->cbyte+= lablen;
 102     if (fls->cbyte > fls->dglen) goto x_truncated;
 103     if (fls->cbyte > fls->max) goto x_badresponse;
 104   } else {
 105     if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
 106   }
 107   *lablen_r= lablen;
 108 /*if (labstart_r) fprintf(stderr,"label %d >%.*s<\n",lablen,lablen,fls->dgram+*labstart_r);*/
 109   return adns_s_ok;
 110
 111  x_truncated:
 112   *lablen_r= -1;
 113   return adns_s_ok;
 114
 115  x_badresponse:
 116   adns__diag(fls->ads,fls->serv,fls->qu,"label in domain runs beyond end of domain");
 117   return adns_s_invalidresponse;
 118 }
 119
 120 adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
 121                                vbuf *vb, adns_queryflags flags,
 122                                const byte *dgram, int dglen, int *cbyte_io, int max) {
 123   findlabel_state fls;
 124
 125   adns__findlabel_start(&fls,ads, serv,qu, dgram,dglen,max, *cbyte_io,cbyte_io);
 126   vb->used= 0;
 127   return adns__parse_domain_more(&fls,ads,qu, vb,flags,dgram);
 128 }
 129
 130 adns_status adns__parse_domain_more(findlabel_state *fls, adns_state ads,
 131                                     adns_query qu, vbuf *vb, parsedomain_flags flags,
 132                                     const byte *dgram) {
 133   int lablen, labstart, i, ch, first;
 134   adns_status st;
 135
 136   first= 1;
 137   for (;;) {
 138     st= adns__findlabel_next(fls,&lablen,&labstart);
 139     if (st) return st;
 140     if (lablen<0) { vb->used=0; return adns_s_ok; }
 141     if (!lablen) break;
 142     if (first) {
 143       first= 0;
 144     } else {
 145       if (!adns__vbuf_append(vb,".",1)) return adns_s_nomemory;
 146     }
 147     if (flags & pdf_quoteok) {
 148       if (!vbuf__append_quoted1035(vb,dgram+labstart,lablen))
 149         return adns_s_nomemory;
 150     } else {
 151       ch= dgram[labstart];
 152       if (!ctype_alpha(ch) && !ctype_digit(ch)) return adns_s_answerdomaininvalid;
 153       for (i= labstart+1; i<labstart+lablen; i++) {
 154         ch= dgram[i];
 155         if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch))
 156           return adns_s_answerdomaininvalid;
 157       }
 158       if (!adns__vbuf_append(vb,dgram+labstart,lablen))
 159         return adns_s_nomemory;
 160     }
 161   }
 162   if (!adns__vbuf_append(vb,"",1)) return adns_s_nomemory;
 163   return adns_s_ok;
 164 }
 165
 166 adns_status adns__findrr_anychk(adns_query qu, int serv,
 167                                 const byte *dgram, int dglen, int *cbyte_io,
 168                                 int *type_r, int *class_r, unsigned long *ttl_r,
 169                                 int *rdlen_r, int *rdstart_r,
 170                                 const byte *eo_dgram, int eo_dglen, int eo_cbyte,
 171                                 int *eo_matched_r) {
 172   findlabel_state fls, eo_fls;
 173   int cbyte;
 174
 175   int tmp, rdlen, mismatch;
 176   unsigned long ttl;
 177   int lablen, labstart, ch;
 178   int eo_lablen, eo_labstart, eo_ch;
 179   adns_status st;
 180
 181   cbyte= *cbyte_io;
 182
 183   adns__findlabel_start(&fls,qu->ads, serv,qu, dgram,dglen,dglen,cbyte,&cbyte);
 184   if (eo_dgram) {
 185     adns__findlabel_start(&eo_fls,qu->ads, -1,0, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0);
 186     mismatch= 0;
 187   } else {
 188     mismatch= 1;
 189   }
 190
 191   for (;;) {
 192     st= adns__findlabel_next(&fls,&lablen,&labstart);
 193     if (st) return st;
 194     if (lablen<0) goto x_truncated;
 195
 196     if (!mismatch) {
 197       st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart);
 198       assert(!st); assert(eo_lablen>=0);
 199       if (lablen != eo_lablen) mismatch= 1;
 200       while (!mismatch && eo_lablen-- > 0) {
 201         ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32;
 202         eo_ch= eo_dgram[eo_labstart++]; if (ctype_alpha(eo_ch)) eo_ch &= ~32;
 203         if (ch != eo_ch) mismatch= 1;
 204       }
 205     }
 206     if (!lablen) break;
 207   }
 208   if (eo_matched_r) *eo_matched_r= !mismatch;
 209
 210   if (cbyte+10>dglen) goto x_truncated;
 211   GET_W(cbyte,tmp); *type_r= tmp;
 212   GET_W(cbyte,tmp); *class_r= tmp;
 213
 214   GET_L(cbyte,ttl);
 215   if (ttl > MAXTTLBELIEVE) ttl= MAXTTLBELIEVE;
 216   *ttl_r= ttl;
 217
 218   GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= rdlen;
 219   if (rdstart_r) *rdstart_r= cbyte;
 220   cbyte+= rdlen;
 221   if (cbyte>dglen) goto x_truncated;
 222   *cbyte_io= cbyte;
 223   return adns_s_ok;
 224
 225  x_truncated:
 226   *type_r= -1;
 227   return 0;
 228 }
 229
 230 adns_status adns__findrr(adns_query qu, int serv,
 231                          const byte *dgram, int dglen, int *cbyte_io,
 232                          int *type_r, int *class_r, unsigned long *ttl_r,
 233                          int *rdlen_r, int *rdstart_r,
 234                          int *ownermatchedquery_r) {
 235   if (!ownermatchedquery_r) {
 236     return adns__findrr_anychk(qu,serv,
 237                                dgram,dglen,cbyte_io,
 238                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 239                                0,0,0, 0);
 240   } else if (!qu->cname_dgram) {
 241     return adns__findrr_anychk(qu,serv,
 242                                dgram,dglen,cbyte_io,
 243                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 244                                qu->query_dgram,qu->query_dglen,DNS_HDRSIZE,
 245                                ownermatchedquery_r);
 246   } else {
 247     return adns__findrr_anychk(qu,serv,
 248                                dgram,dglen,cbyte_io,
 249                                type_r,class_r,ttl_r,rdlen_r,rdstart_r,
 250                                qu->cname_dgram,qu->cname_dglen,qu->cname_begin,
 251                                ownermatchedquery_r);
 252   }
 253 }