src/icmp/pinger.cc

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