110 lines
3.3 KiB
C
110 lines
3.3 KiB
C
/* $Id: udns_rr_ptr.c,v 1.15 2005/09/12 11:21:06 mjt Exp $
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parse/query PTR 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 <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_ptr(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_ptr *ret;
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struct dns_parse p;
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struct dns_rr rr;
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int r, l, c;
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char *sp;
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dnsc_t ptr[DNS_MAXDN];
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assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_PTR);
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/* first, validate the answer and count size of the result */
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l = c = 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;
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r = dns_getdn(pkt, &cur, end, ptr, sizeof(ptr));
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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(ptr);
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++c;
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}
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if (r < 0)
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return DNS_E_PROTOCOL;
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if (!c)
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return DNS_E_NODATA;
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/* next, allocate and set up result */
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ret = malloc(sizeof(*ret) + sizeof(char **) * c + l + dns_stdrr_size(&p));
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if (!ret)
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return DNS_E_NOMEM;
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ret->dnsptr_nrr = c;
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ret->dnsptr_ptr = (char **)(ret+1);
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/* and 3rd, fill in result, finally */
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sp = (char*)(ret->dnsptr_ptr + c);
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c = 0;
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dns_rewind(&p, qdn);
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while((r = dns_nextrr(&p, &rr)) > 0) {
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ret->dnsptr_ptr[c] = sp;
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cur = rr.dnsrr_dptr;
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dns_getdn(pkt, &cur, end, ptr, sizeof(ptr));
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sp += dns_dntop(ptr, sp, DNS_MAXNAME);
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++c;
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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_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr,
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dns_query_ptr_fn *cbck, void *data) {
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dnsc_t dn[DNS_A4RSIZE];
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dns_a4todn(addr, 0, dn, sizeof(dn));
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return
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dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH,
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dns_parse_ptr, (dns_query_fn *)cbck, data);
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}
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struct dns_rr_ptr *
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dns_resolve_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr) {
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return (struct dns_rr_ptr *)
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dns_resolve(ctx, dns_submit_a4ptr(ctx, addr, NULL, NULL));
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}
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struct dns_query *
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dns_submit_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr,
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dns_query_ptr_fn *cbck, void *data) {
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dnsc_t dn[DNS_A6RSIZE];
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dns_a6todn(addr, 0, dn, sizeof(dn));
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return
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dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH,
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dns_parse_ptr, (dns_query_fn *)cbck, data);
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}
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struct dns_rr_ptr *
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dns_resolve_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr) {
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return (struct dns_rr_ptr *)
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dns_resolve(ctx, dns_submit_a6ptr(ctx, addr, NULL, NULL));
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}
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