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94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/* libanode: the Anode C reference implementation
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* Copyright (C) 2009-2010 Adam Ierymenko <adam.ierymenko@gmail.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <resolv.h>
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#include <netdb.h>
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#include "dns_txt.h"
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#ifndef C_IN
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#define C_IN ns_c_in
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#endif
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#ifndef T_TXT
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#define T_TXT ns_t_txt
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#endif
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static volatile int Anode_resolver_initialized = 0;
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int Anode_sync_resolve_txt(const char *host,char *txt,unsigned int txt_len)
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{
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unsigned char answer[16384],*pptr,*end;
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char name[16384];
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int len,explen,i;
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if (!Anode_resolver_initialized) {
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Anode_resolver_initialized = 1;
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res_init();
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}
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/* Do not taunt happy fun ball. */
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len = res_search(host,C_IN,T_TXT,answer,sizeof(answer));
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if (len > 12) {
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pptr = answer + 12;
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end = answer + len;
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explen = dn_expand(answer,end,pptr,name,sizeof(name));
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if (explen > 0) {
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pptr += explen;
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if ((pptr + 2) >= end) return 2;
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if (ntohs(*((uint16_t *)pptr)) == T_TXT) {
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pptr += 4;
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if (pptr >= end) return 2;
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explen = dn_expand(answer,end,pptr,name,sizeof(name));
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if (explen > 0) {
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pptr += explen;
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if ((pptr + 2) >= end) return 2;
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if (ntohs(*((uint16_t *)pptr)) == T_TXT) {
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pptr += 10;
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if (pptr >= end) return 2;
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len = *(pptr++);
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if (len <= 0) return 2;
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if ((pptr + len) > end) return 2;
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if (txt_len < (len + 1))
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return 4;
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else {
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for(i=0;i<len;++i)
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txt[i] = pptr[i];
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txt[len] = (char)0;
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return 0;
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}
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}
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}
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}
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}
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}
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return 1;
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}
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