"Fossies" - the Fresh Open Source Software Archive

Member "udns-0.4/udns_rr_ptr.c" (5 Jul 2011, 3384 Bytes) of package /linux/misc/dns/udns-0.4.tar.gz:

    1 /* udns_rr_ptr.c
    2    parse/query PTR records
    3 
    4    Copyright (C) 2005  Michael Tokarev <mjt@corpit.ru>
    5    This file is part of UDNS library, an async DNS stub resolver.
    6 
    7    This library is free software; you can redistribute it and/or
    8    modify it under the terms of the GNU Lesser General Public
    9    License as published by the Free Software Foundation; either
   10    version 2.1 of the License, or (at your option) any later version.
   11 
   12    This library is distributed in the hope that it will be useful,
   13    but WITHOUT ANY WARRANTY; without even the implied warranty of
   14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   15    Lesser General Public License for more details.
   16 
   17    You should have received a copy of the GNU Lesser General Public
   18    License along with this library, in file named COPYING.LGPL; if not,
   19    write to the Free Software Foundation, Inc., 59 Temple Place,
   20    Suite 330, Boston, MA  02111-1307  USA
   21 
   22  */
   23 
   24 #include <stdlib.h>
   25 #include <assert.h>
   26 #include "udns.h"
   27 
   28 int
   29 dns_parse_ptr(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end,
   30               void **result) {
   31   struct dns_rr_ptr *ret;
   32   struct dns_parse p;
   33   struct dns_rr rr;
   34   int r, l, c;
   35   char *sp;
   36   dnsc_t ptr[DNS_MAXDN];
   37 
   38   assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_PTR);
   39 
   40   /* first, validate the answer and count size of the result */
   41   l = c = 0;
   42   dns_initparse(&p, qdn, pkt, cur, end);
   43   while((r = dns_nextrr(&p, &rr)) > 0) {
   44     cur = rr.dnsrr_dptr;
   45     r = dns_getdn(pkt, &cur, end, ptr, sizeof(ptr));
   46     if (r <= 0 || cur != rr.dnsrr_dend)
   47       return DNS_E_PROTOCOL;
   48     l += dns_dntop_size(ptr);
   49     ++c;
   50   }
   51   if (r < 0)
   52     return DNS_E_PROTOCOL;
   53   if (!c)
   54     return DNS_E_NODATA;
   55 
   56   /* next, allocate and set up result */
   57   ret = malloc(sizeof(*ret) + sizeof(char **) * c + l + dns_stdrr_size(&p));
   58   if (!ret)
   59     return DNS_E_NOMEM;
   60   ret->dnsptr_nrr = c;
   61   ret->dnsptr_ptr = (char **)(ret+1);
   62 
   63   /* and 3rd, fill in result, finally */
   64   sp = (char*)(ret->dnsptr_ptr + c);
   65   c = 0;
   66   dns_rewind(&p, qdn);
   67   while((r = dns_nextrr(&p, &rr)) > 0) {
   68     ret->dnsptr_ptr[c] = sp;
   69     cur = rr.dnsrr_dptr;
   70     dns_getdn(pkt, &cur, end, ptr, sizeof(ptr));
   71     sp += dns_dntop(ptr, sp, DNS_MAXNAME);
   72     ++c;
   73   }
   74   dns_stdrr_finish((struct dns_rr_null *)ret, sp, &p);
   75   *result = ret;
   76   return 0;
   77 }
   78 
   79 struct dns_query *
   80 dns_submit_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr,
   81                  dns_query_ptr_fn *cbck, void *data) {
   82   dnsc_t dn[DNS_A4RSIZE];
   83   dns_a4todn(addr, 0, dn, sizeof(dn));
   84   return
   85     dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH,
   86                   dns_parse_ptr, (dns_query_fn *)cbck, data);
   87 }
   88 
   89 struct dns_rr_ptr *
   90 dns_resolve_a4ptr(struct dns_ctx *ctx, const struct in_addr *addr) {
   91   return (struct dns_rr_ptr *)
   92     dns_resolve(ctx, dns_submit_a4ptr(ctx, addr, NULL, NULL));
   93 }
   94 
   95 struct dns_query *
   96 dns_submit_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr,
   97                  dns_query_ptr_fn *cbck, void *data) {
   98   dnsc_t dn[DNS_A6RSIZE];
   99   dns_a6todn(addr, 0, dn, sizeof(dn));
  100   return
  101     dns_submit_dn(ctx, dn, DNS_C_IN, DNS_T_PTR, DNS_NOSRCH,
  102                   dns_parse_ptr, (dns_query_fn *)cbck, data);
  103 }
  104 
  105 struct dns_rr_ptr *
  106 dns_resolve_a6ptr(struct dns_ctx *ctx, const struct in6_addr *addr) {
  107   return (struct dns_rr_ptr *)
  108     dns_resolve(ctx, dns_submit_a6ptr(ctx, addr, NULL, NULL));
  109 }