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