src/icmp/pinger.cc

   1 /*
   2  * $Id: pinger.cc,v 1.62 2008/02/26 21:49:35 amosjeffries Exp $
   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 #endif
  80 #include <process.h>
  81 #include "fde.h"
  82
  83 #define PINGER_TIMEOUT 5
  84
  85 /* windows uses the control socket for feedback to squid */
  86 #define LINK_TO_SQUID squid_link
  87
  88 // windows still requires WSAFD but there are too many dependancy problems
  89 // to just link to win32.cc where it is normally defined.
  90
  91 int
  92 Win32__WSAFDIsSet(int fd, fd_set FAR * set)
  93 {
  94     fde *F = &fd_table[fd];
  95     SOCKET s = F->win32.handle;
  96
  97     return __WSAFDIsSet(s, set);
  98 }
  99
 100 #else
 101
 102 #define PINGER_TIMEOUT 10
 103
 104 /* non-windows use STDOUT for feedback to squid */
 105 #define LINK_TO_SQUID   1
 106
 107 #endif  /* _SQUID_MSWIN_ */
 108
 109 // ICMP Engines are declared global here so they can call each other easily.
 110 IcmpPinger control;
 111 Icmp4 icmp4;
 112 #if USE_IPV6
 113 Icmp6 icmp6;
 114 #endif
 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 #if USE_IPV6
 143     int icmp6_worker = -1;
 144 #endif
 145     int squid_link = -1;
 146
 147     /** start by initializing the pinger debug cache.log-pinger. */
 148     if ((t = getenv("SQUID_DEBUG")))
 149         debug_args = xstrdup(t);
 150
 151     getCurrentTime();
 152
 153     _db_init(NULL, debug_args);
 154
 155     debugs(42, 0, "pinger: Initialising ICMP pinger ...");
 156
 157     icmp4_worker = icmp4.Open();
 158     if (icmp4_worker < 0) {
 159         debugs(42, 0, "pinger: Unable to start ICMP pinger.");
 160     }
 161     max_fd = max(max_fd, icmp4_worker);
 162
 163 #if USE_IPV6
 164     icmp6_worker = icmp6.Open();
 165     if (icmp6_worker <0 ) {
 166         debugs(42, 0, "pinger: Unable to start ICMPv6 pinger.");
 167     }
 168     max_fd = max(max_fd, icmp6_worker);
 169 #endif
 170
 171     /** abort if neither worker could open a socket. */
 172     if (icmp4_worker == -1) {
 173 #if USE_IPV6
 174         if (icmp6_worker == -1)
 175 #endif
 176         {
 177             debugs(42, 0, "FATAL: pinger: Unable to open any ICMP sockets.");
 178             exit(1);
 179         }
 180     }
 181
 182     if ( (squid_link = control.Open()) < 0) {
 183         debugs(42, 0, "FATAL: pinger: Unable to setup Pinger control sockets.");
 184         icmp4.Close();
 185 #if USE_IPV6
 186         icmp6.Close();
 187 #endif
 188         exit(1); // fatal error if the control channel fails.
 189     }
 190     max_fd = max(max_fd, squid_link);
 191
 192     setgid(getgid());
 193     setuid(getuid());
 194
 195     for (;;) {
 196         tv.tv_sec = PINGER_TIMEOUT;
 197         tv.tv_usec = 0;
 198         FD_ZERO(&R);
 199         if (icmp4_worker >= 0) {
 200             FD_SET(icmp4_worker, &R);
 201         }
 202 #if USE_IPV6
 203
 204         if (icmp6_worker >= 0) {
 205             FD_SET(icmp6_worker, &R);
 206         }
 207 #endif
 208         FD_SET(squid_link, &R);
 209         x = select(10, &R, NULL, NULL, &tv);
 210         getCurrentTime();
 211
 212         if (x < 0) {
 213             debugs(42, 0, HERE << " FATAL Shutdown. select()==" << x << ", ERR: " << xstrerror());
 214             control.Close();
 215             exit(1);
 216         }
 217
 218         if (FD_ISSET(squid_link, &R)) {
 219             control.Recv();
 220         }
 221
 222 #if USE_IPV6
 223         if (icmp6_worker >= 0 && FD_ISSET(icmp6_worker, &R)) {
 224             icmp6.Recv();
 225         }
 226 #endif
 227
 228         if (icmp4_worker >= 0 && FD_ISSET(icmp4_worker, &R)) {
 229             icmp4.Recv();
 230         }
 231
 232         if (PINGER_TIMEOUT + last_check_time < squid_curtime) {
 233             if (send(LINK_TO_SQUID, &tv, 0, 0) < 0) {
 234                 debugs(42, 0, "pinger: Closing. No requests in last " << PINGER_TIMEOUT << " seconds.");
 235                 control.Close();
 236                 exit(1);
 237             }
 238
 239             last_check_time = squid_curtime;
 240         }
 241     }
 242
 243     /* NOTREACHED */
 244     return 0;
 245 }
 246
 247 #else
 248 #include <stdio.h>
 249 int
 250 main(int argc, char *argv[])
 251 {
 252     fprintf(stderr, "%s: ICMP support not compiled in.\n", argv[0]);
 253     return 1;
 254 }
 255
 256 #endif /* USE_ICMP */