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Member "udns-0.4/udns_rr_mx.c" (5 Jul 2011, 2878 Bytes) of package /linux/misc/dns/udns-0.4.tar.gz:


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    1 /* udns_rr_mx.c
    2    parse/query MX IN 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 <string.h>
   25 #include <stdlib.h>
   26 #include <assert.h>
   27 #include "udns.h"
   28 
   29 int
   30 dns_parse_mx(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end,
   31              void **result) {
   32   struct dns_rr_mx *ret;
   33   struct dns_parse p;
   34   struct dns_rr rr;
   35   int r, l;
   36   char *sp;
   37   dnsc_t mx[DNS_MAXDN];
   38 
   39   assert(dns_get16(cur+2) == DNS_C_IN && dns_get16(cur+0) == DNS_T_MX);
   40 
   41   /* first, validate the answer and count size of the result */
   42   l = 0;
   43   dns_initparse(&p, qdn, pkt, cur, end);
   44   while((r = dns_nextrr(&p, &rr)) > 0) {
   45     cur = rr.dnsrr_dptr + 2;
   46     r = dns_getdn(pkt, &cur, end, mx, sizeof(mx));
   47     if (r <= 0 || cur != rr.dnsrr_dend)
   48       return DNS_E_PROTOCOL;
   49     l += dns_dntop_size(mx);
   50   }
   51   if (r < 0)
   52     return DNS_E_PROTOCOL;
   53   if (!p.dnsp_nrr)
   54     return DNS_E_NODATA;
   55 
   56   /* next, allocate and set up result */
   57   l += dns_stdrr_size(&p);
   58   ret = malloc(sizeof(*ret) + sizeof(struct dns_mx) * p.dnsp_nrr + l);
   59   if (!ret)
   60     return DNS_E_NOMEM;
   61   ret->dnsmx_nrr = p.dnsp_nrr;
   62   ret->dnsmx_mx = (struct dns_mx *)(ret+1);
   63 
   64   /* and 3rd, fill in result, finally */
   65   sp = (char*)(ret->dnsmx_mx + p.dnsp_nrr);
   66   for (dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr); ++r) {
   67     ret->dnsmx_mx[r].name = sp;
   68     cur = rr.dnsrr_dptr;
   69     ret->dnsmx_mx[r].priority = dns_get16(cur);
   70     cur += 2;
   71     dns_getdn(pkt, &cur, end, mx, sizeof(mx));
   72     sp += dns_dntop(mx, sp, DNS_MAXNAME);
   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_mx(struct dns_ctx *ctx, const char *name, int flags,
   81               dns_query_mx_fn *cbck, void *data) {
   82   return
   83     dns_submit_p(ctx, name, DNS_C_IN, DNS_T_MX, flags,
   84                  dns_parse_mx, (dns_query_fn *)cbck, data);
   85 }
   86 
   87 struct dns_rr_mx *
   88 dns_resolve_mx(struct dns_ctx *ctx, const char *name, int flags) {
   89   return (struct dns_rr_mx *)
   90     dns_resolve_p(ctx, name, DNS_C_IN, DNS_T_MX, flags, dns_parse_mx);
   91 }