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 #include "ip/tools.h"
  74
  75 #if _SQUID_WINDOWS_
  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_WINDOWS_ */
 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     // determine IPv4 or IPv6 capabilities before using sockets.
 152     Ip::ProbeTransport();
 153
 154     _db_init(NULL, debug_args);
 155
 156     debugs(42, DBG_CRITICAL, "pinger: Initialising ICMP pinger ...");
 157
 158     icmp4_worker = icmp4.Open();
 159     if (icmp4_worker < 0) {
 160         debugs(42, DBG_CRITICAL, "pinger: Unable to start ICMP pinger.");
 161     }
 162     max_fd = max(max_fd, icmp4_worker);
 163
 164 #if USE_IPV6
 165     icmp6_worker = icmp6.Open();
 166     if (icmp6_worker <0 ) {
 167         debugs(42, DBG_CRITICAL, "pinger: Unable to start ICMPv6 pinger.");
 168     }
 169     max_fd = max(max_fd, icmp6_worker);
 170 #endif
 171
 172     /** abort if neither worker could open a socket. */
 173     if (icmp4_worker < 0 && icmp6_worker < 0) {
 174         debugs(42, DBG_CRITICAL, "FATAL: pinger: Unable to open any ICMP sockets.");
 175         exit(1);
 176     }
 177
 178     if ( (squid_link = control.Open()) < 0) {
 179         debugs(42, DBG_CRITICAL, "FATAL: pinger: Unable to setup Pinger control sockets.");
 180         icmp4.Close();
 181         icmp6.Close();
 182         exit(1); // fatal error if the control channel fails.
 183     }
 184     max_fd = max(max_fd, squid_link);
 185
 186     if (setgid(getgid()) < 0) {
 187         debugs(42, DBG_CRITICAL, "FATAL: pinger: setgid(" << getgid() << ") failed: " << xstrerror());
 188         icmp4.Close();
 189         icmp6.Close();
 190         exit (1);
 191     }
 192     if (setuid(getuid()) < 0) {
 193         debugs(42, DBG_CRITICAL, "FATAL: pinger: setuid(" << getuid() << ") failed: " << xstrerror());
 194         icmp4.Close();
 195         icmp6.Close();
 196         exit (1);
 197     }
 198
 199     last_check_time = squid_curtime;
 200
 201     for (;;) {
 202         tv.tv_sec = PINGER_TIMEOUT;
 203         tv.tv_usec = 0;
 204         FD_ZERO(&R);
 205         if (icmp4_worker >= 0) {
 206             FD_SET(icmp4_worker, &R);
 207         }
 208         if (icmp6_worker >= 0) {
 209             FD_SET(icmp6_worker, &R);
 210         }
 211
 212         FD_SET(squid_link, &R);
 213         x = select(10, &R, NULL, NULL, &tv);
 214         getCurrentTime();
 215
 216         if (x < 0) {
 217             debugs(42, DBG_CRITICAL, HERE << " FATAL Shutdown. select()==" << x << ", ERR: " << xstrerror());
 218             control.Close();
 219             exit(1);
 220         }
 221
 222         if (FD_ISSET(squid_link, &R)) {
 223             control.Recv();
 224         }
 225
 226         if (icmp6_worker >= 0 && FD_ISSET(icmp6_worker, &R)) {
 227             icmp6.Recv();
 228         }
 229         if (icmp4_worker >= 0 && FD_ISSET(icmp4_worker, &R)) {
 230             icmp4.Recv();
 231         }
 232
 233         if (PINGER_TIMEOUT + last_check_time < squid_curtime) {
 234             if (send(LINK_TO_SQUID, &tv, 0, 0) < 0) {
 235                 debugs(42, DBG_CRITICAL, "pinger: Closing. No requests in last " << PINGER_TIMEOUT << " seconds.");
 236                 control.Close();
 237                 exit(1);
 238             }
 239
 240             last_check_time = squid_curtime;
 241         }
 242     }
 243
 244     /* NOTREACHED */
 245     return 0;
 246 }
 247
 248 #else / * !USE_ICMP */
 249
 250 #include <ostream>
 251 int
 252 main(int argc, char *argv[])
 253 {
 254     std::cerr << argv[0] << ": ICMP support not compiled in." << std::endl;
 255     return 1;
 256 }
 257
 258 #endif /* USE_ICMP */