root/src/udns/udns_rr_txt.c

Revision 5a9b91bc0a14543e0995eba973fbeacc05aaee8b, 2.9 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 6 years ago)

svn merge -r 327:330 https://labs.omniti.com/reconnoiter/branches/dev/udns .

closes #38

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1 /* $Id: udns_rr_txt.c,v 1.15 2006/11/28 22:45:20 mjt Exp $
2    parse/query TXT 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_txt(dnscc_t *qdn, dnscc_t *pkt, dnscc_t *cur, dnscc_t *end,
31               void **result) {
32   struct dns_rr_txt *ret;
33   struct dns_parse p;
34   struct dns_rr rr;
35   int r, l;
36   dnsc_t *sp;
37   dnscc_t *cp, *ep;
38
39   assert(dns_get16(cur+0) == DNS_T_TXT);
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     cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
46     while(cp < ep) {
47       r = *cp++;
48       if (cp + r > ep)
49         return DNS_E_PROTOCOL;
50       l += r;
51       cp += r;
52     }
53   }
54   if (r < 0)
55     return DNS_E_PROTOCOL;
56   if (!p.dnsp_nrr)
57     return DNS_E_NODATA;
58
59   /* next, allocate and set up result */
60   l +=  (sizeof(struct dns_txt) + 1) * p.dnsp_nrr + dns_stdrr_size(&p);
61   ret = malloc(sizeof(*ret) + l);
62   if (!ret)
63     return DNS_E_NOMEM;
64   ret->dnstxt_nrr = p.dnsp_nrr;
65   ret->dnstxt_txt = (struct dns_txt *)(ret+1);
66
67   /* and 3rd, fill in result, finally */
68   sp = (dnsc_t*)(ret->dnstxt_txt + p.dnsp_nrr);
69   for(dns_rewind(&p, qdn), r = 0; dns_nextrr(&p, &rr) > 0; ++r) {
70     ret->dnstxt_txt[r].txt = sp;
71     cp = rr.dnsrr_dptr; ep = rr.dnsrr_dend;
72     while(cp < ep) {
73       l = *cp++;
74       memcpy(sp, cp, l);
75       sp += l;
76       cp += l;
77     }
78     ret->dnstxt_txt[r].len = sp - ret->dnstxt_txt[r].txt;
79     *sp++ = '\0';
80   }
81   dns_stdrr_finish((struct dns_rr_null *)ret, (char*)sp, &p);
82   *result = ret;
83   return 0;
84 }
85
86 struct dns_query *
87 dns_submit_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags,
88                dns_query_txt_fn *cbck, void *data) {
89   return
90     dns_submit_p(ctx, name, qcls, DNS_T_TXT, flags,
91                  dns_parse_txt, (dns_query_fn *)cbck, data);
92 }
93
94 struct dns_rr_txt *
95 dns_resolve_txt(struct dns_ctx *ctx, const char *name, int qcls, int flags) {
96   return (struct dns_rr_txt *)
97     dns_resolve_p(ctx, name, qcls, DNS_T_TXT, flags, dns_parse_txt);
98 }
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