You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

110 lines
3.3 KiB

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