src/dns.cc

   1
   2 /*
   3  * $Id: dns.cc,v 1.100 2007/04/28 22:26:37 hno Exp $
   4  *
   5  * DEBUG: section 34    Dnsserver interface
   6  * AUTHOR: Harvest Derived
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "Store.h"
  38 #include "wordlist.h"
  39 #include "SquidTime.h"
  40 #include "CacheManager.h"
  41 #include "helper.h"
  42
  43 /* MS VisualStudio Projects are monolitich, so we need the following
  44    #if to include the external DNS code in compile process when
  45    using external DNS.
  46  */
  47 #if USE_DNSSERVERS
  48
  49 static helper *dnsservers = NULL;
  50
  51 static void
  52 dnsStats(StoreEntry * sentry)
  53 {
  54     storeAppendPrintf(sentry, "Dnsserver Statistics:\n");
  55     helperStats(sentry, dnsservers);
  56 }
  57
  58 void
  59 dnsInit(void)
  60 {
  61     wordlist *w;
  62
  63     if (!Config.Program.dnsserver)
  64         return;
  65
  66     if (dnsservers == NULL)
  67         dnsservers = helperCreate("dnsserver");
  68
  69     dnsservers->n_to_start = Config.dnsChildren;
  70
  71     dnsservers->ipc_type = IPC_STREAM;
  72
  73     assert(dnsservers->cmdline == NULL);
  74
  75     wordlistAdd(&dnsservers->cmdline, Config.Program.dnsserver);
  76
  77     if (Config.onoff.res_defnames)
  78         wordlistAdd(&dnsservers->cmdline, "-D");
  79
  80     for (w = Config.dns_nameservers; w != NULL; w = w->next) {
  81         wordlistAdd(&dnsservers->cmdline, "-s");
  82         wordlistAdd(&dnsservers->cmdline, w->key);
  83     }
  84
  85     helperOpenServers(dnsservers);
  86 }
  87
  88 void
  89 dnsRegisterWithCacheManager(CacheManager & manager)
  90 {
  91     manager.registerAction("dns",
  92                            "Dnsserver Statistics",
  93                            dnsStats, 0, 1);
  94 }
  95
  96 void
  97 dnsShutdown(void)
  98 {
  99     if (!dnsservers)
 100         return;
 101
 102     helperShutdown(dnsservers);
 103
 104     wordlistDestroy(&dnsservers->cmdline);
 105
 106     if (!shutting_down)
 107         return;
 108
 109     helperFree(dnsservers);
 110
 111     dnsservers = NULL;
 112 }
 113
 114 void
 115 dnsSubmit(const char *lookup, HLPCB * callback, void *data)
 116 {
 117     char buf[256];
 118     static time_t first_warn = 0;
 119     snprintf(buf, 256, "%s\n", lookup);
 120
 121     if (dnsservers->stats.queue_size >= dnsservers->n_running * 2) {
 122         if (first_warn == 0)
 123             first_warn = squid_curtime;
 124
 125         if (squid_curtime - first_warn > 3 * 60)
 126             fatal("DNS servers not responding for 3 minutes");
 127
 128         debugs(34, 1, "dnsSubmit: queue overload, rejecting " << lookup);
 129
 130         callback(data, (char *)"$fail Temporary network problem, please retry later");
 131
 132         return;
 133     }
 134
 135     first_warn = 0;
 136     helperSubmit(dnsservers, buf, callback, data);
 137 }
 138
 139 #ifdef SQUID_SNMP
 140 /*
 141  * The function to return the DNS via SNMP
 142  */
 143 variable_list *
 144 snmp_netDnsFn(variable_list * Var, snint * ErrP)
 145 {
 146     variable_list *Answer = NULL;
 147     debugs(49, 5, "snmp_netDnsFn: Processing request: " << Var->name[LEN_SQ_NET + 1]);
 148     snmpDebugOid(5, Var->name, Var->name_length);
 149     *ErrP = SNMP_ERR_NOERROR;
 150
 151     switch (Var->name[LEN_SQ_NET + 1]) {
 152
 153     case DNS_REQ:
 154         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 155                                       dnsservers->stats.requests,
 156                                       SMI_COUNTER32);
 157         break;
 158
 159     case DNS_REP:
 160         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 161                                       dnsservers->stats.replies,
 162                                       SMI_COUNTER32);
 163         break;
 164
 165     case DNS_SERVERS:
 166         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 167                                       dnsservers->n_running,
 168                                       SMI_COUNTER32);
 169         break;
 170
 171     default:
 172         *ErrP = SNMP_ERR_NOSUCHNAME;
 173         break;
 174     }
 175
 176     return Answer;
 177 }
 178
 179 #endif /*SQUID_SNMP */
 180 #endif /* USE_DNSSERVERS */