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