/*
 * parse.c
 * - parsing assistance functions (mainly for domains inside datagrams)
 */
/*
 *  This file is
 *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
 *
 *  It is part of adns, which is
 *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
 *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
 *  
 *  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. 
 *
 * $Id: parse.c,v 1.2 2003/06/14 13:55:50 tr-ircd Exp $
 */

#include "struct.h"
#include "fileio.h"
#include "ircsprintf.h"
#include "internal.h"

int vbuf__append_quoted1035(vbuf * vb, const byte * buf, int len)
{
    byte qbuf[10];
    int i, ch;

    while (len) {
	qbuf[0] = 0;
	for (i = 0; i < len; i++) {
	    ch = buf[i];
	    if (ch <= ' ' || ch >= 127) {
		ircsprintf((char *) qbuf, "\\%03o", ch);
		break;
	    } else if (!ctype_domainunquoted(ch)) {
		ircsprintf((char *) qbuf, "\\%c", ch);
		break;
	    }
	}
	if (!adns__vbuf_append(vb, buf, i) ||
	    !adns__vbuf_append(vb, qbuf, strlen((const char *) 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, jumpto;
    const char *dgram;

    dgram = (const char *) 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 (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;
    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, parsedomain_flags flags,
			       const byte * dgram, int dglen, int *cbyte_io, int max)
{
findlabel_state fls;

    adns__findlabel_start(&fls, ads, serv, qu, dgram, dglen, max, *cbyte_io, cbyte_io);
    vb->used = 0;
    return adns__parse_domain_more(&fls, ads, qu, vb, flags, dgram);
}

adns_status adns__parse_domain_more(findlabel_state * fls, adns_state ads,
				    adns_query qu, vbuf * vb,
				    parsedomain_flags flags, const byte * dgram)
{
int lablen, labstart, i, ch, first;
adns_status st;

    first = 1;
    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 (first) {
	    first = 0;
	} else {
	    if (!adns__vbuf_append(vb, (const byte *) ".", 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, (const byte *) "", 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, unsigned long *ttl_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;
unsigned long ttl;
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;

    GET_L(cbyte, ttl);
    if (ttl > MAXTTLBELIEVE)
	ttl = MAXTTLBELIEVE;
    *ttl_r = 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, unsigned long *ttl_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, ttl_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, ttl_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, ttl_r, rdlen_r, rdstart_r,
				   qu->cname_dgram, qu->cname_dglen,
				   qu->cname_begin, ownermatchedquery_r);
    }
}