Improved error discrimination / set of errors.

[adns] / src / parse.c

/*
 * parse.c
 * - parsing assistance functions (mainly for domains inside datagrams)
 */
/*
 *  This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software Foundation,
 *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
 */

#include "internal.h"

int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) {
  char qbuf[10];
  int i, ch;
  
  while (len) {
    qbuf[0]= 0;
    for (i=0; i<len; i++) {
      ch= buf[i];
      if (ch == '.' || ch == '"' || ch == '(' || ch == ')' ||
          ch == '@' || ch == ';' || ch == '$' || ch == '\\') {
        sprintf(qbuf,"\\%c",ch);
        break;
      } else if (ch <= ' ' || ch >= 127) {
        sprintf(qbuf,"\\%03o",ch);
        break;
      }
    }
    if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf)))
      return 0;
    if (i<len) i++;
    buf+= i;
    len-= i;
  }
  return 1;
}

void adns__findlabel_start(findlabel_state *fls, adns_state ads,
                           int serv, adns_query qu,
                           const byte *dgram, int dglen, int max,
                           int dmbegin, int *dmend_rlater) {
  fls->ads= ads;
  fls->qu= qu;
  fls->serv= serv;
  fls->dgram= dgram;
  fls->dglen= dglen;
  fls->max= max;
  fls->cbyte= dmbegin;
  fls->namelen= 0;
  fls->dmend_r= dmend_rlater;
}

adns_status adns__findlabel_next(findlabel_state *fls,
                                 int *lablen_r, int *labstart_r) {
  int lablen, jumped, jumpto;
  const char *dgram;

  jumped= 0;
  dgram= fls->dgram;
  for (;;) {
    if (fls->cbyte >= fls->dglen) goto x_truncated;
    if (fls->cbyte >= fls->max) goto x_badresponse;
    GET_B(fls->cbyte,lablen);
    if (!(lablen & 0x0c0)) break;
    if ((lablen & 0x0c0) != 0x0c0) return adns_s_unknownformat;
    if (jumped++) {
      adns__diag(fls->ads,fls->serv,fls->qu,"compressed datagram contains loop");
      return adns_s_invalidresponse;
    }
    if (fls->cbyte >= fls->dglen) goto x_truncated;
    if (fls->cbyte >= fls->max) goto x_badresponse;
    GET_B(fls->cbyte,jumpto);
    jumpto |= (lablen&0x3f)<<8;
    if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
    fls->cbyte= jumpto;
    fls->dmend_r= 0; fls->max= fls->dglen+1;
  }
  if (labstart_r) *labstart_r= fls->cbyte;
  if (lablen) {
    if (fls->namelen) fls->namelen++;
    fls->namelen+= lablen;
    if (fls->namelen > DNS_MAXDOMAIN) return adns_s_answerdomaintoolong;
    fls->cbyte+= lablen;
    if (fls->cbyte > fls->dglen) goto x_truncated;
    if (fls->cbyte > fls->max) goto x_badresponse;
  } else {
    if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte;
  }
  *lablen_r= lablen;
/*if (labstart_r) fprintf(stderr,"label %d >%.*s<\n",lablen,lablen,fls->dgram+*labstart_r);*/
  return adns_s_ok;

 x_truncated:
  *lablen_r= -1;
  return adns_s_ok;

 x_badresponse: 
  adns__diag(fls->ads,fls->serv,fls->qu,"label in domain runs beyond end of domain");
  return adns_s_invalidresponse;
}

adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu,
                               vbuf *vb, adns_queryflags flags,
                               const byte *dgram, int dglen, int *cbyte_io, int max) {
  findlabel_state fls;
  
  int lablen, labstart, i, ch;
  adns_status st;

  adns__findlabel_start(&fls,ads, serv,qu, dgram,dglen,max, *cbyte_io,cbyte_io);
  vb->used= 0;
  for (;;) {
    st= adns__findlabel_next(&fls,&lablen,&labstart);
    if (st) return st;
    if (lablen<0) { vb->used=0; return adns_s_ok; }
    if (!lablen) break;
    if (vb->used)
      if (!adns__vbuf_append(vb,".",1)) return adns_s_nomemory;
    if (flags & pdf_quoteok) {
      if (!vbuf__append_quoted1035(vb,dgram+labstart,lablen))
        return adns_s_nomemory;
    } else {
      ch= dgram[labstart];
      if (!ctype_alpha(ch) && !ctype_digit(ch)) return adns_s_answerdomaininvalid;
      for (i= labstart+1; i<labstart+lablen; i++) {
        ch= dgram[i];
        if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch))
          return adns_s_answerdomaininvalid;
      }
      if (!adns__vbuf_append(vb,dgram+labstart,lablen))
        return adns_s_nomemory;
    }
  }
  if (!adns__vbuf_append(vb,"",1)) return adns_s_nomemory;
  return adns_s_ok;
}
        
adns_status adns__findrr_anychk(adns_query qu, int serv,
                                const byte *dgram, int dglen, int *cbyte_io,
                                int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
                                const byte *eo_dgram, int eo_dglen, int eo_cbyte,
                                int *eo_matched_r) {
  findlabel_state fls, eo_fls;
  int cbyte;
  
  int tmp, rdlen, mismatch;
  int lablen, labstart, ch;
  int eo_lablen, eo_labstart, eo_ch;
  adns_status st;

  cbyte= *cbyte_io;

  adns__findlabel_start(&fls,qu->ads, serv,qu, dgram,dglen,dglen,cbyte,&cbyte);
  if (eo_dgram) {
    adns__findlabel_start(&eo_fls,qu->ads, -1,0, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0);
    mismatch= 0;
  } else {
    mismatch= 1;
  }
  
  for (;;) {
    st= adns__findlabel_next(&fls,&lablen,&labstart);
    if (st) return st;
    if (lablen<0) goto x_truncated;

    if (!mismatch) {
      st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart);
      assert(!st); assert(eo_lablen>=0);
      if (lablen != eo_lablen) mismatch= 1;
      while (!mismatch && eo_lablen-- > 0) {
        ch= dgram[labstart++]; if (ctype_alpha(ch)) ch &= ~32;
        eo_ch= eo_dgram[eo_labstart++]; if (ctype_alpha(eo_ch)) eo_ch &= ~32;
        if (ch != eo_ch) mismatch= 1;
      }
    }
    if (!lablen) break;
  }
  if (eo_matched_r) *eo_matched_r= !mismatch;
   
  if (cbyte+10>dglen) goto x_truncated;
  GET_W(cbyte,tmp); *type_r= tmp;
  GET_W(cbyte,tmp); *class_r= tmp;
  cbyte+= 4; /* we skip the TTL */
  GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= rdlen;
  if (rdstart_r) *rdstart_r= cbyte;
  cbyte+= rdlen;
  if (cbyte>dglen) goto x_truncated;
  *cbyte_io= cbyte;
  return adns_s_ok;

 x_truncated:
  *type_r= -1;
  return 0;
}

adns_status adns__findrr(adns_query qu, int serv,
                         const byte *dgram, int dglen, int *cbyte_io,
                         int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
                         int *ownermatchedquery_r) {
  if (!ownermatchedquery_r) {
    return adns__findrr_anychk(qu,serv,
                               dgram,dglen,cbyte_io,
                               type_r,class_r,rdlen_r,rdstart_r,
                               0,0,0, 0);
  } else if (!qu->cname_dgram) {
    return adns__findrr_anychk(qu,serv,
                               dgram,dglen,cbyte_io,
                               type_r,class_r,rdlen_r,rdstart_r,
                               qu->query_dgram,qu->query_dglen,DNS_HDRSIZE,
                               ownermatchedquery_r);
  } else {
    return adns__findrr_anychk(qu,serv,
                               dgram,dglen,cbyte_io,
                               type_r,class_r,rdlen_r,rdstart_r,
                               qu->cname_dgram,qu->cname_dglen,qu->cname_begin,
                               ownermatchedquery_r);
  }
}