99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
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/* udns_rr_txt.c
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parse/query TXT records
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Copyright (C) 2005 Michael Tokarev <mjt@corpit.ru>
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This file is part of UDNS library, an async DNS stub resolver.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library, in file named COPYING.LGPL; if not,
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write to the Free Software Foundation, Inc., 59 Temple Place,
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Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "udns.h"
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int
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dns_parse_txt(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end,
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void **result) {
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struct dns_rr_txt *ret;
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struct dns_parse p;
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struct dns_rr rr;
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int r, l;
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dnsc_t *sp;
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dnscc_t *cp, *ep;
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assert(dns_get16(cur+0) == DNS_T_TXT);
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/* first, validate the answer and count size of the result */
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l = 0;
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dns_initparse(&p, qdn, pkt, cur, end);
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while((r = dns_nextrr(&p, &rr)) > 0) {
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cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
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while(cp < ep) {
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r = *cp++;
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if (cp + r > ep)
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return DNS_E_PROTOCOL;
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l += r;
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cp += r;
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}
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}
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if (r < 0)
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return DNS_E_PROTOCOL;
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if (!p.dnsp_nrr)
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return DNS_E_NODATA;
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/* next, allocate and set up result */
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l += (sizeof(struct dns_txt) + 1) * p.dnsp_nrr + dns_stdrr_size(&p);
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ret = malloc(sizeof(*ret) + l);
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if (!ret)
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return DNS_E_NOMEM;
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ret->dnstxt_nrr = p.dnsp_nrr;
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ret->dnstxt_txt = (struct dns_txt *)(ret+1);
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/* and 3rd, fill in result, finally */
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sp = (dnsc_t*)(ret->dnstxt_txt + p.dnsp_nrr);
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for(dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr) > 0; ++r) {
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ret->dnstxt_txt[r].txt = sp;
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cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
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while(cp < ep) {
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l = *cp++;
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memcpy(sp, cp, l);
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sp += l;
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cp += l;
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}
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ret->dnstxt_txt[r].len = sp - ret->dnstxt_txt[r].txt;
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*sp++ = '\0';
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}
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dns_stdrr_finish((struct dns_rr_null *)ret, (char*)sp, &p);
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*result = ret;
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return 0;
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}
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struct dns_query *
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dns_submit_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags,
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dns_query_txt_fn *cbck, void *data) {
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return
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dns_submit_p(ctx, name, qcls, DNS_T_TXT, flags,
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dns_parse_txt, (dns_query_fn *)cbck, data);
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}
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struct dns_rr_txt *
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dns_resolve_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags) {
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return (struct dns_rr_txt *)
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dns_resolve_p(ctx, name, qcls, DNS_T_TXT, flags, dns_parse_txt);
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}
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