92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
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/* udns_rr_mx.c
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parse/query MX IN 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_mx(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_mx *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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char *sp;
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dnsc_t mx[DNS_MAXDN];
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assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_MX);
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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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cur = rr.dnsrr_dptr + 2;
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r = dns_getdn(pkt, &cur, end, mx, sizeof(mx));
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if (r <= 0 || cur != rr.dnsrr_dend)
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return DNS_E_PROTOCOL;
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l += dns_dntop_size(mx);
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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 += dns_stdrr_size(&p);
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ret = malloc(sizeof(*ret) + sizeof(struct dns_mx) * p.dnsp_nrr + l);
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if (!ret)
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return DNS_E_NOMEM;
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ret->dnsmx_nrr = p.dnsp_nrr;
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ret->dnsmx_mx = (struct dns_mx *)(ret+1);
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/* and 3rd, fill in result, finally */
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sp = (char*)(ret->dnsmx_mx + p.dnsp_nrr);
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for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) {
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ret->dnsmx_mx[r].name = sp;
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cur = rr.dnsrr_dptr;
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ret->dnsmx_mx[r].priority = dns_get16(cur);
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cur += 2;
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dns_getdn(pkt, &cur, end, mx, sizeof(mx));
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sp += dns_dntop(mx, sp, DNS_MAXNAME);
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}
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dns_stdrr_finish((struct dns_rr_null *)ret, 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_mx(struct dns_ctx *ctx, const char *name, int flags,
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dns_query_mx_fn *cbck, void *data) {
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return
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dns_submit_p(ctx, name, DNS_C_IN, DNS_T_MX, flags,
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dns_parse_mx, (dns_query_fn *)cbck, data);
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}
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struct dns_rr_mx *
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dns_resolve_mx(struct dns_ctx *ctx, const char *name, int flags) {
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return (struct dns_rr_mx *)
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dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_MX, flags, dns_parse_mx);
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}
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