src/icmp/pinger.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 42    ICMP Pinger program
   5  * AUTHOR: Duane Wessels
   6  *
   7  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   8  * ----------------------------------------------------------
   9  *
  10  *  Squid is the result of efforts by numerous individuals from
  11  *  the Internet community; see the CONTRIBUTORS file for full
  12  *  details.   Many organizations have provided support for Squid's
  13  *  development; see the SPONSORS file for full details.  Squid is
  14  *  Copyrighted (C) 2001 by the Regents of the University of
  15  *  California; see the COPYRIGHT file for full details.  Squid
  16  *  incorporates software developed and/or copyrighted by other
  17  *  sources; see the CREDITS file for full details.
  18  *
  19  *  This program is free software; you can redistribute it and/or modify
  20  *  it under the terms of the GNU General Public License as published by
  21  *  the Free Software Foundation; either version 2 of the License, or
  22  *  (at your option) any later version.
  23  *
  24  *  This program is distributed in the hope that it will be useful,
  25  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  *  GNU General Public License for more details.
  28  *
  29  *  You should have received a copy of the GNU General Public License
  30  *  along with this program; if not, write to the Free Software
  31  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  32  *
  33  */
  34
  35 #define SQUID_HELPER 1
  36
  37 /**
  38  \defgroup pinger pinger
  39  \ingroup ExternalPrograms
  40  \par
  41  *   Although it would be possible for Squid to send and receive
  42  *   ICMP messages directly, we use an external process for
  43  *   two important reasons:
  44  *
  45  \li Because squid handles many filedescriptors simultaneously,
  46  *   we get much more accurate RTT measurements when ICMP is
  47  *   handled by a separate process.
  48  *
  49  \li Superuser privileges are required to send and receive ICMP.
  50  *   Rather than require Squid to be started as root, we prefer
  51  *   to have the smaller and simpler pinger program installed
  52  *   with setuid permissions.
  53  *
  54  \par
  55  *   If you want to use Squid's ICMP features (highly recommended!)
  56  *   When USE_ICMP is defined, Squid will send ICMP pings
  57  *   to origin server sites.
  58  *   This information is used in numerous ways:
  59  \li  - Sent in ICP replies so neighbor caches know how close
  60  *      you are to the source.
  61  \li  - For finding the closest instance of a URN.
  62  \li  - With the 'test_reachability' option.  Squid will return
  63  *      ICP_OP_MISS_NOFETCH for sites which it cannot ping.
  64  */
  65
  66 #include "squid.h"
  67 #include "SquidTime.h"
  68
  69 #if USE_ICMP
  70
  71 #include "Icmp4.h"
  72 #include "Icmp6.h"
  73 #include "IcmpPinger.h"
  74
  75 #ifdef _SQUID_MSWIN_
  76
  77 #if HAVE_WINSOCK2_H
  78 #include <winsock2.h>
  79 #elif HAVE_WINSOCK_H
  80 #include <winsock.h>
  81 #endif
  82 #include <process.h>
  83 #include "fde.h"
  84
  85 #define PINGER_TIMEOUT 5
  86
  87 /* windows uses the control socket for feedback to squid */
  88 #define LINK_TO_SQUID squid_link
  89
  90 // windows still requires WSAFD but there are too many dependancy problems
  91 // to just link to win32.cc where it is normally defined.
  92
  93 int
  94 Win32__WSAFDIsSet(int fd, fd_set FAR * set)
  95 {
  96     fde *F = &fd_table[fd];
  97     SOCKET s = F->win32.handle;
  98
  99     return __WSAFDIsSet(s, set);
 100 }
 101
 102 #else
 103
 104 #define PINGER_TIMEOUT 10
 105
 106 /* non-windows use STDOUT for feedback to squid */
 107 #define LINK_TO_SQUID   1
 108
 109 #endif  /* _SQUID_MSWIN_ */
 110
 111 // ICMP Engines are declared global here so they can call each other easily.
 112 IcmpPinger control;
 113 Icmp4 icmp4;
 114 Icmp6 icmp6;
 115
 116 int icmp_pkts_sent = 0;
 117
 118 /**
 119  \ingroup pinger
 120  \par This is the pinger external process.
 121  *
 122  \param argc Ignored.
 123  \param argv Ignored.
 124  */
 125 int
 126 main(int argc, char *argv[])
 127 {
 128     fd_set R;
 129     int x;
 130     int max_fd = 0;
 131
 132     struct timeval tv;
 133     const char *debug_args = "ALL,10";
 134     char *t;
 135     time_t last_check_time = 0;
 136
 137     /*
 138      * cevans - do this first. It grabs a raw socket. After this we can
 139      * drop privs
 140      */
 141     int icmp4_worker = -1;
 142     int icmp6_worker = -1;
 143     int squid_link = -1;
 144
 145     /** start by initializing the pinger debug cache.log-pinger. */
 146     if ((t = getenv("SQUID_DEBUG")))
 147         debug_args = xstrdup(t);
 148
 149     getCurrentTime();
 150
 151     _db_init(NULL, debug_args);
 152
 153     debugs(42, 0, "pinger: Initialising ICMP pinger ...");
 154
 155     icmp4_worker = icmp4.Open();
 156     if (icmp4_worker < 0) {
 157         debugs(42, 0, "pinger: Unable to start ICMP pinger.");
 158     }
 159     max_fd = max(max_fd, icmp4_worker);
 160
 161 #if USE_IPV6
 162     icmp6_worker = icmp6.Open();
 163     if (icmp6_worker <0 ) {
 164         debugs(42, 0, "pinger: Unable to start ICMPv6 pinger.");
 165     }
 166     max_fd = max(max_fd, icmp6_worker);
 167 #endif
 168
 169     /** abort if neither worker could open a socket. */
 170     if (icmp4_worker < 0 && icmp6_worker < 0) {
 171         debugs(42, 0, "FATAL: pinger: Unable to open any ICMP sockets.");
 172         exit(1);
 173     }
 174
 175     if ( (squid_link = control.Open()) < 0) {
 176         debugs(42, 0, "FATAL: pinger: Unable to setup Pinger control sockets.");
 177         icmp4.Close();
 178         icmp6.Close();
 179         exit(1); // fatal error if the control channel fails.
 180     }
 181     max_fd = max(max_fd, squid_link);
 182
 183     setgid(getgid());
 184     setuid(getuid());
 185
 186     last_check_time = squid_curtime;
 187
 188     for (;;) {
 189         tv.tv_sec = PINGER_TIMEOUT;
 190         tv.tv_usec = 0;
 191         FD_ZERO(&R);
 192         if (icmp4_worker >= 0) {
 193             FD_SET(icmp4_worker, &R);
 194         }
 195         if (icmp6_worker >= 0) {
 196             FD_SET(icmp6_worker, &R);
 197         }
 198
 199         FD_SET(squid_link, &R);
 200         x = select(10, &R, NULL, NULL, &tv);
 201         getCurrentTime();
 202
 203         if (x < 0) {
 204             debugs(42, 0, HERE << " FATAL Shutdown. select()==" << x << ", ERR: " << xstrerror());
 205             control.Close();
 206             exit(1);
 207         }
 208
 209         if (FD_ISSET(squid_link, &R)) {
 210             control.Recv();
 211         }
 212
 213         if (icmp6_worker >= 0 && FD_ISSET(icmp6_worker, &R)) {
 214             icmp6.Recv();
 215         }
 216         if (icmp4_worker >= 0 && FD_ISSET(icmp4_worker, &R)) {
 217             icmp4.Recv();
 218         }
 219
 220         if (PINGER_TIMEOUT + last_check_time < squid_curtime) {
 221             if (send(LINK_TO_SQUID, &tv, 0, 0) < 0) {
 222                 debugs(42, 0, "pinger: Closing. No requests in last " << PINGER_TIMEOUT << " seconds.");
 223                 control.Close();
 224                 exit(1);
 225             }
 226
 227             last_check_time = squid_curtime;
 228         }
 229     }
 230
 231     /* NOTREACHED */
 232     return 0;
 233 }
 234
 235 #else
 236 #include <stdio.h>
 237 int
 238 main(int argc, char *argv[])
 239 {
 240     fprintf(stderr, "%s: ICMP support not compiled in.\n", argv[0]);
 241     return 1;
 242 }
 243
 244 #endif /* USE_ICMP */