mirror of
https://github.com/matrix-construct/construct
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This could lead to pretty nasty things, like losing DNS (and in the future, ident) queries. That's a Bad Thing™.
359 lines
6.5 KiB
C
359 lines
6.5 KiB
C
/*
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* dns.c: An interface to the resolver module in authd
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* (based somewhat on ircd-ratbox dns.c)
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*
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* Copyright (C) 2005 Aaron Sethman <androsyn@ratbox.org>
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* Copyright (C) 2005-2012 ircd-ratbox development team
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* Copyright (C) 2016 William Pitcock <nenolod@dereferenced.org>
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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 2 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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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* USA
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*/
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#include "stdinc.h"
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#include "rb_lib.h"
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#include "client.h"
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#include "ircd_defs.h"
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#include "parse.h"
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#include "dns.h"
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#include "match.h"
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#include "logger.h"
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#include "s_conf.h"
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#include "client.h"
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#include "send.h"
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#include "numeric.h"
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#include "msg.h"
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#include "hash.h"
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#define DNS_IDTABLE_SIZE 0x2000
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#define DNS_STATTABLE_SIZE 0x10
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#define DNS_HOST_IPV4 ((char)'4')
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#define DNS_HOST_IPV6 ((char)'6')
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#define DNS_REVERSE_IPV4 ((char)'R')
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#define DNS_REVERSE_IPV6 ((char)'S')
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static void submit_dns(uint16_t uid, char type, const char *addr);
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static void submit_dns_stat(uint16_t uid);
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struct dnsreq
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{
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DNSCB callback;
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void *data;
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};
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struct dnsstatreq
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{
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DNSLISTCB callback;
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void *data;
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};
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static struct dnsreq querytable[DNS_IDTABLE_SIZE];
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static struct dnsstatreq stattable[DNS_STATTABLE_SIZE];
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rb_dlink_list nameservers;
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static uint16_t
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assign_dns_id(void)
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{
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static uint16_t id = 1;
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int loopcnt = 0;
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while(1)
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{
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if(++loopcnt > DNS_IDTABLE_SIZE)
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return 0;
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if(id < DNS_IDTABLE_SIZE - 1 || id == 0)
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id++;
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else
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id = 1;
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if(querytable[id].callback == NULL)
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break;
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}
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return (id);
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}
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static uint8_t
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assign_dns_stat_id(void)
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{
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static uint8_t id = 1;
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int loopcnt = 0;
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while(1)
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{
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if(++loopcnt > DNS_STATTABLE_SIZE)
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return 0;
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if(id < DNS_STATTABLE_SIZE - 1 || id == 0)
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id++;
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else
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id = 1;
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if(stattable[id].callback == NULL)
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break;
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}
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return (id);
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}
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static void
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handle_dns_failure(uint16_t xid)
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{
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struct dnsreq *req;
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req = &querytable[xid];
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if(req->callback == NULL)
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return;
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req->callback("FAILED", 0, 0, req->data);
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req->callback = NULL;
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req->data = NULL;
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}
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static void
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handle_dns_stat_failure(uint8_t xid)
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{
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struct dnsstatreq *req;
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const char *err[] = { "Unknown failure" };
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req = &stattable[xid];
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if(req->callback == NULL)
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return;
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req->callback(1, err, 2, req->data);
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req->callback = NULL;
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req->data = NULL;
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}
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void
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cancel_lookup(uint16_t xid)
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{
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querytable[xid].callback = NULL;
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querytable[xid].data = NULL;
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}
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void
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cancel_dns_stats(uint16_t xid)
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{
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stattable[xid].callback = NULL;
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stattable[xid].data = NULL;
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}
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uint16_t
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lookup_hostname(const char *hostname, int aftype, DNSCB callback, void *data)
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{
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struct dnsreq *req;
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int aft;
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uint16_t nid;
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check_authd();
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nid = assign_dns_id();
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if((nid = assign_dns_id()) == 0)
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return 0;
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req = &querytable[nid];
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req->callback = callback;
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req->data = data;
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#ifdef RB_IPV6
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if(aftype == AF_INET6)
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aft = 6;
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else
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#endif
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aft = 4;
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submit_dns(nid, aft == 4 ? DNS_HOST_IPV4 : DNS_HOST_IPV6, hostname);
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return (nid);
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}
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uint16_t
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lookup_ip(const char *addr, int aftype, DNSCB callback, void *data)
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{
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struct dnsreq *req;
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int aft;
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uint16_t nid;
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check_authd();
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if((nid = assign_dns_id()) == 0)
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return 0;
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req = &querytable[nid];
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req->callback = callback;
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req->data = data;
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#ifdef RB_IPV6
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if(aftype == AF_INET6)
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aft = 6;
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else
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#endif
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aft = 4;
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submit_dns(nid, aft == 4 ? DNS_REVERSE_IPV4 : DNS_REVERSE_IPV6, addr);
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return (nid);
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}
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uint8_t
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get_nameservers(DNSLISTCB callback, void *data)
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{
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struct dnsstatreq *req;
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uint8_t nid;
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check_authd();
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if((nid = assign_dns_stat_id()) == 0)
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return 0;
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req = &stattable[nid];
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req->callback = callback;
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req->data = data;
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submit_dns_stat(nid);
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return (nid);
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}
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void
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dns_results_callback(const char *callid, const char *status, const char *type, const char *results)
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{
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struct dnsreq *req;
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uint16_t nid;
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int st;
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int aft;
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long lnid = strtol(callid, NULL, 16);
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if(lnid > DNS_IDTABLE_SIZE || lnid == 0)
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return;
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nid = (uint16_t)lnid;
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req = &querytable[nid];
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st = (*status == 'O');
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aft = *type == '6' || *type == 'S' ? 6 : 4;
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if(req->callback == NULL)
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{
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/* got cancelled..oh well */
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req->data = NULL;
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return;
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}
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#ifdef RB_IPV6
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if(aft == 6)
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aft = AF_INET6;
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else
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#endif
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aft = AF_INET;
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req->callback(results, st, aft, req->data);
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req->callback = NULL;
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req->data = NULL;
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}
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void
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dns_stats_results_callback(const char *callid, const char *status, int resc, const char *resv[])
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{
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struct dnsstatreq *req;
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uint8_t nid;
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int st, i;
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long lnid = strtol(callid, NULL, 16);
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if(lnid > DNS_STATTABLE_SIZE || lnid == 0)
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return;
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nid = (uint8_t)lnid;
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req = &stattable[nid];
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if(req->callback == NULL)
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{
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req->data = NULL;
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return;
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}
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switch(*status)
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{
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case 'Y':
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st = 0;
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break;
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case 'X':
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/* Error */
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st = 1;
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break;
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default:
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/* Shouldn't happen... */
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return;
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}
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/* Query complete */
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req->callback(resc, resv, st, stattable[nid].data);
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req->data = NULL;
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req->callback = NULL;
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}
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static void
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get_nameservers_cb(int resc, const char *resv[], int status, void *data)
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{
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if(status == 0)
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{
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rb_dlink_node *n, *tn;
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RB_DLINK_FOREACH_SAFE(n, tn, nameservers.head)
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{
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/* Clean up old nameservers */
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rb_free(n->data);
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rb_dlinkDestroy(n, &nameservers);
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}
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for(int i = 0; i < resc; i++)
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rb_dlinkAddAlloc(rb_strdup(resv[i]), &nameservers);
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}
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else
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{
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const char *error = resc ? resv[resc] : "Unknown error";
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iwarn("Error getting DNS servers: %s", error);
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}
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}
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void
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init_nameserver_cache(void)
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{
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(void)get_nameservers(get_nameservers_cb, NULL);
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}
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bool
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reload_nameservers(void)
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{
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if(authd_helper == NULL)
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{
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/* Shit */
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return false;
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}
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rb_helper_write(authd_helper, "C D");
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init_nameserver_cache();
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return true;
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}
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static void
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submit_dns(uint16_t nid, char type, const char *addr)
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{
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if(authd_helper == NULL)
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{
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handle_dns_failure(nid);
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return;
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}
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rb_helper_write(authd_helper, "D %x %c %s", nid, type, addr);
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}
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static void
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submit_dns_stat(uint16_t nid)
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{
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if(authd_helper == NULL)
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{
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handle_dns_stat_failure(nid);
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return;
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}
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rb_helper_write(authd_helper, "S %x D", nid);
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}
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