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/* $Id: udns_rr_txt.c,v 1.15 2006/11/28 22:45:20 mjt Exp $
parse/query TXT records
Copyright (C) 2005 Michael Tokarev <mjt@corpit.ru>
This file is part of UDNS library, an async DNS stub resolver.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library, in file named COPYING.LGPL; if not,
write to the Free Software Foundation, Inc., 59 Temple Place,
Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include "udns.h"
int
dns_parse_txt(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end,
void **result) {
struct dns_rr_txt *ret;
struct dns_parse p;
struct dns_rr rr;
int r, l;
dnsc_t *sp;
dnscc_t *cp, *ep;
assert(dns_get16(cur+0) == DNS_T_TXT);
/* first, validate the answer and count size of the result */
l = 0;
dns_initparse(&p, qdn, pkt, cur, end);
while((r = dns_nextrr(&p, &rr)) > 0) {
cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
while(cp < ep) {
r = *cp++;
if (cp + r > ep)
return DNS_E_PROTOCOL;
l += r;
cp += r;
}
}
if (r < 0)
return DNS_E_PROTOCOL;
if (!p.dnsp_nrr)
return DNS_E_NODATA;
/* next, allocate and set up result */
l += (sizeof(struct dns_txt) + 1) * p.dnsp_nrr + dns_stdrr_size(&p);
ret = malloc(sizeof(*ret) + l);
if (!ret)
return DNS_E_NOMEM;
ret->dnstxt_nrr = p.dnsp_nrr;
ret->dnstxt_txt = (struct dns_txt *)(ret+1);
/* and 3rd, fill in result, finally */
sp = (dnsc_t*)(ret->dnstxt_txt + p.dnsp_nrr);
for(dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr) > 0; ++r) {
ret->dnstxt_txt[r].txt = sp;
cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
while(cp < ep) {
l = *cp++;
memcpy(sp, cp, l);
sp += l;
cp += l;
}
ret->dnstxt_txt[r].len = sp - ret->dnstxt_txt[r].txt;
*sp++ = '\0';
}
dns_stdrr_finish((struct dns_rr_null *)ret, (char*)sp, &p);
*result = ret;
return 0;
}
struct dns_query *
dns_submit_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags,
dns_query_txt_fn *cbck, void *data) {
return
dns_submit_p(ctx, name, qcls, DNS_T_TXT, flags,
dns_parse_txt, (dns_query_fn *)cbck, data);
}
struct dns_rr_txt *
dns_resolve_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags) {
return (struct dns_rr_txt *)
dns_resolve_p(ctx, name, qcls, DNS_T_TXT, flags, dns_parse_txt);
}
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