src/dns.cc

   1
   2 /*
   3  * $Id$
   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 static void
  59 dnsRegisterWithCacheManager(void)
  60 {
  61     CacheManager::GetInstance()->
  62     registerAction("dns", "Dnsserver Statistics", dnsStats, 0, 1);
  63 }
  64
  65 void
  66 dnsInit(void)
  67 {
  68     wordlist *w;
  69
  70     dnsRegisterWithCacheManager();
  71
  72     if (!Config.Program.dnsserver)
  73         return;
  74
  75     if (dnsservers == NULL)
  76         dnsservers = helperCreate("dnsserver");
  77
  78     dnsservers->n_to_start = Config.dnsChildren;
  79
  80     dnsservers->ipc_type = IPC_STREAM;
  81
  82     assert(dnsservers->cmdline == NULL);
  83
  84     wordlistAdd(&dnsservers->cmdline, Config.Program.dnsserver);
  85
  86     if (Config.onoff.res_defnames)
  87         wordlistAdd(&dnsservers->cmdline, "-D");
  88
  89     for (w = Config.dns_nameservers; w != NULL; w = w->next) {
  90         wordlistAdd(&dnsservers->cmdline, "-s");
  91         wordlistAdd(&dnsservers->cmdline, w->key);
  92     }
  93
  94     helperOpenServers(dnsservers);
  95 }
  96
  97 void
  98 dnsShutdown(void)
  99 {
 100     if (!dnsservers)
 101         return;
 102
 103     helperShutdown(dnsservers);
 104
 105     wordlistDestroy(&dnsservers->cmdline);
 106
 107     if (!shutting_down)
 108         return;
 109
 110     helperFree(dnsservers);
 111
 112     dnsservers = NULL;
 113 }
 114
 115 void
 116 dnsSubmit(const char *lookup, HLPCB * callback, void *data)
 117 {
 118     char buf[256];
 119     static time_t first_warn = 0;
 120     snprintf(buf, 256, "%s\n", lookup);
 121
 122     if (dnsservers->stats.queue_size >= dnsservers->n_running * 2) {
 123         if (first_warn == 0)
 124             first_warn = squid_curtime;
 125
 126         if (squid_curtime - first_warn > 3 * 60)
 127             fatal("DNS servers not responding for 3 minutes");
 128
 129         debugs(34, 1, "dnsSubmit: queue overload, rejecting " << lookup);
 130
 131         callback(data, (char *)"$fail Temporary network problem, please retry later");
 132
 133         return;
 134     }
 135
 136     first_warn = 0;
 137     helperSubmit(dnsservers, buf, callback, data);
 138 }
 139
 140 #ifdef SQUID_SNMP
 141 /*
 142  * The function to return the DNS via SNMP
 143  */
 144 variable_list *
 145 snmp_netDnsFn(variable_list * Var, snint * ErrP)
 146 {
 147     variable_list *Answer = NULL;
 148     debugs(49, 5, "snmp_netDnsFn: Processing request: " << Var->name[LEN_SQ_NET + 1]);
 149     snmpDebugOid(5, Var->name, Var->name_length);
 150     *ErrP = SNMP_ERR_NOERROR;
 151
 152     switch (Var->name[LEN_SQ_NET + 1]) {
 153
 154     case DNS_REQ:
 155         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 156                                       dnsservers->stats.requests,
 157                                       SMI_COUNTER32);
 158         break;
 159
 160     case DNS_REP:
 161         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 162                                       dnsservers->stats.replies,
 163                                       SMI_COUNTER32);
 164         break;
 165
 166     case DNS_SERVERS:
 167         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 168                                       dnsservers->n_running,
 169                                       SMI_COUNTER32);
 170         break;
 171
 172     default:
 173         *ErrP = SNMP_ERR_NOSUCHNAME;
 174         break;
 175     }
 176
 177     return Answer;
 178 }
 179
 180 #endif /*SQUID_SNMP */
 181 #endif /* USE_DNSSERVERS */