server/dhcpd.c

   1 /* dhcpd.c
   2
   3    DHCP Server Daemon. */
   4
   5 /*
   6  * Copyright (c) 1995, 1996, 1997, 1998, 1999
   7  * The Internet Software Consortium.   All rights reserved.
   8  *
   9  * Redistribution and use of this source file, source files derived in whole
  10  * or in part from this source file, and binary files derived in whole or in
  11  * part from this source file, with or without modification, are permitted
  12  * provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  *    This copyright notice must appear directly below any initial commentary
  17  *    describing the file, and may not be preceded by any other copyright
  18  *    notice.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  * 3. Neither the name of The Internet Software Consortium (hereafter
  23  *    referred to as "the ISC") nor the names of its contributors may be
  24  *    used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  * 4. This software is a part of the ISC DHCP Distribution.  Redistributions
  27  *    of this source file or binary files derived from this source file
  28  *    MUST include all documentation accompanying the ISC release from
  29  *    which such redistributions are derived of this source file, specifically
  30  *    the following files (listed relative to the top of the ISC DHCP
  31  *    distribution directory tree):
  32  *
  33  *              README
  34  *              common/dhcp-contrib.5
  35  *              common/dhcp-options.5
  36  *              server/dhcpd.8
  37  *              server/dhcpd.conf.5
  38  *              server/dhcpd.leases.5
  39  *              client/dhclient.8
  40  *              client/dhclient.conf.5
  41  *              client/dhclient-script.8
  42  *              client/dhclient.leases.5
  43  *              relay/dhcrelay.8
  44  *
  45  *    Absence of these files from a distribution you receive does not excuse
  46  *    you from this requirement - if the distribution you receive does not
  47  *    contain these files, you must get them from the ISC and include them
  48  *    in any redistribution of this source file or any derivative work based
  49  *    wholly or in part on this source file.   It is permissible in a binary
  50  *    redistribution derived from this source file to include formatted
  51  *    versions of the manual pages mentioned above, and also to add to or
  52  *    correct the manual pages and README file mentioned above so long as the
  53  *    sections labeled CONTRIBUTIONS in these documents are unchanged except
  54  *    with respect to formatting, so long as the order in which the
  55  *    CONTRIBUTIONS section appears in these documents is not changed, and
  56  *    so long as the dhcp-contrib.5 manual page is unchanged except with
  57  *    respect to formatting.   It is also permissible to redistribute this
  58  *    source file, source files derived wholly or in part from this source
  59  *    file, and binaries derived wholly or in part from this source file
  60  *    accompanied by the aforementioned manual pages translated into another
  61  *    language.   In this case, the CONTRIBUTIONS section and the
  62  *    dhcp-contrib.5 section may either be left in their original language
  63  *    or translated into the new language with such care and diligence as
  64  *    is required to preserve the original meaning.
  65  * 5. If, in addition to the documentation mentioned in section 4, this
  66  *    source file, a source file derived wholly or in part from this source
  67  *    file, or a binary file derived wholly or in part from this source file
  68  *    is redistributed with additional printed or electronic documentation,
  69  *    then that documentation must refer to the dhcp-contrib.5 manual page
  70  *    in as conspicuous a way as the aforementioned documentation refers to
  71  *    it, and the dhcp-contrib.5 manual page must be converted into the same
  72  *    format and be made easily accessible to any recipient of such
  73  *    redistributions.
  74  *
  75  * THIS SOFTWARE IS PROVIDED BY THE ISC AND CONTRIBUTORS ``AS IS'' AND ANY
  76  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  77  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  78  * DISCLAIMED.  IN NO EVENT SHALL THE ISC OR CONTRIBUTORS BE LIABLE FOR ANY
  79  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  80  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  81  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  82  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  83  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
  84  * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  85  * SUCH DAMAGE.
  86  *
  87  * This software has been written for the ISC by Ted Lemon <mellon@isc.org>
  88  * in cooperation with Vixie Enterprises and Internet Engines, Inc.  To
  89  * learn more about the ISC, see ``http://www.vix.com/isc''.   Development
  90  * of this software is funded through contributions and support contracts.
  91  * Please see the dhcp-contrib manual page that accompanies this file for
  92  * information on how you can contribute.
  93  */
  94
  95 #ifndef lint
  96 static char ocopyright[] =
  97 "$Id: dhcpd.c,v 1.58 1999/03/16 00:56:36 mellon Exp $ Copyright 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.";
  98 #endif
  99
 100   static char copyright[] =
 101 "Copyright 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.";
 102 static char arr [] = "All rights reserved.";
 103 static char message [] = "Internet Software Consortium DHCP Server V3.0-alpha 980315";
 104 static char contrib [] = "\nPlease contribute if you find this software useful.";
 105 static char url [] = "For info, please visit http://www.isc.org/dhcp-contrib.html\n";
 106
 107 #include "dhcpd.h"
 108
 109 static void usage PROTO ((void));
 110
 111 TIME cur_time;
 112 struct group root_group;
 113
 114 struct iaddr server_identifier;
 115 int server_identifier_matched;
 116
 117 u_int16_t local_port;
 118 u_int16_t remote_port;
 119
 120 int log_priority;
 121 #ifdef DEBUG
 122 int log_perror = -1;
 123 #else
 124 int log_perror = 1;
 125 #endif
 126
 127 char *path_dhcpd_conf = _PATH_DHCPD_CONF;
 128 char *path_dhcpd_db = _PATH_DHCPD_DB;
 129 char *path_dhcpd_pid = _PATH_DHCPD_PID;
 130
 131 int dhcp_max_agent_option_packet_length = DHCP_MTU_MAX;
 132
 133 int main (argc, argv, envp)
 134         int argc;
 135         char **argv, **envp;
 136 {
 137         int i, status;
 138         struct servent *ent;
 139         char *s;
 140         int cftest = 0;
 141 #ifndef DEBUG
 142         int pidfilewritten = 0;
 143         int pid;
 144         char pbuf [20];
 145         int daemon = 1;
 146 #endif
 147         int quiet = 0;
 148
 149         /* Initially, log errors to stderr as well as to syslogd. */
 150 #ifdef SYSLOG_4_2
 151         openlog ("dhcpd", LOG_NDELAY);
 152         log_priority = DHCPD_LOG_FACILITY;
 153 #else
 154         openlog ("dhcpd", LOG_NDELAY, DHCPD_LOG_FACILITY);
 155 #endif
 156
 157 #ifndef DEBUG
 158 #ifndef SYSLOG_4_2
 159 #ifndef __CYGWIN32__ /* XXX */
 160         setlogmask (LOG_UPTO (LOG_INFO));
 161 #endif
 162 #endif
 163 #endif
 164
 165         for (i = 1; i < argc; i++) {
 166                 if (!strcmp (argv [i], "-p")) {
 167                         if (++i == argc)
 168                                 usage ();
 169                         for (s = argv [i]; *s; s++)
 170                                 if (!isdigit (*s))
 171                                         log_fatal ("%s: not a valid UDP port",
 172                                                argv [i]);
 173                         status = atoi (argv [i]);
 174                         if (status < 1 || status > 65535)
 175                                 log_fatal ("%s: not a valid UDP port",
 176                                        argv [i]);
 177                         local_port = htons (status);
 178                         log_debug ("binding to user-specified port %d",
 179                                ntohs (local_port));
 180                 } else if (!strcmp (argv [i], "-f")) {
 181 #ifndef DEBUG
 182                         daemon = 0;
 183 #endif
 184                 } else if (!strcmp (argv [i], "-d")) {
 185 #ifndef DEBUG
 186                         daemon = 0;
 187 #endif
 188                         log_perror = -1;
 189                 } else if (!strcmp (argv [i], "-cf")) {
 190                         if (++i == argc)
 191                                 usage ();
 192                         path_dhcpd_conf = argv [i];
 193                 } else if (!strcmp (argv [i], "-lf")) {
 194                         if (++i == argc)
 195                                 usage ();
 196                         path_dhcpd_db = argv [i];
 197                 } else if (!strcmp (argv [i], "-pf")) {
 198                         if (++i == argc)
 199                                 usage ();
 200                         path_dhcpd_pid = argv [i];
 201                 } else if (!strcmp (argv [i], "-t")) {
 202                         /* test configurations only */
 203 #ifndef DEBUG
 204                         daemon = 0;
 205 #endif
 206                         cftest = 1;
 207                         log_perror = -1;
 208                 } else if (!strcmp (argv [i], "-q")) {
 209                         quiet = 1;
 210                         quiet_interface_discovery = 1;
 211                 } else if (argv [i][0] == '-') {
 212                         usage ();
 213                 } else {
 214                         struct interface_info *tmp =
 215                                 ((struct interface_info *)
 216                                  dmalloc (sizeof *tmp, "get_interface_list"));
 217                         if (!tmp)
 218                                 log_fatal ("Insufficient memory to %s %s",
 219                                        "record interface", argv [i]);
 220                         memset (tmp, 0, sizeof *tmp);
 221                         strcpy (tmp -> name, argv [i]);
 222                         tmp -> next = interfaces;
 223                         tmp -> flags = INTERFACE_REQUESTED;
 224                         interfaces = tmp;
 225                 }
 226         }
 227
 228         if (!quiet) {
 229                 log_info (message);
 230                 log_info (copyright);
 231                 log_info (arr);
 232                 log_info (contrib);
 233                 log_info (url);
 234         }
 235
 236         /* Default to the DHCP/BOOTP port. */
 237         if (!local_port)
 238         {
 239                 ent = getservbyname ("dhcp", "udp");
 240                 if (!ent)
 241                         local_port = htons (67);
 242                 else
 243                         local_port = ent -> s_port;
 244 #ifndef __CYGWIN32__ /* XXX */
 245                 endservent ();
 246 #endif
 247         }
 248
 249         remote_port = htons (ntohs (local_port) + 1);
 250
 251         /* Get the current time... */
 252         GET_TIME (&cur_time);
 253
 254         /* Initialize DNS support... */
 255 #if 0
 256         dns_startup ();
 257 #endif
 258
 259         /* Start the interactive client listener. */
 260         interact_startup ();
 261
 262         /* Set up the client classification system. */
 263         classification_setup ();
 264
 265         /* Read the dhcpd.conf file... */
 266         if (!readconf ())
 267                 log_fatal ("Configuration file errors encountered -- exiting");
 268
 269         /* test option should cause an early exit */
 270         if (cftest)
 271                 exit(0);
 272
 273         /* Start up the database... */
 274         db_startup ();
 275
 276         /* Discover all the network interfaces and initialize them. */
 277         discover_interfaces (DISCOVER_SERVER);
 278
 279         /* Initialize icmp support... */
 280         icmp_startup (1, lease_pinged);
 281
 282 #ifndef DEBUG
 283         if (daemon) {
 284                 /* First part of becoming a daemon... */
 285                 if ((pid = fork ()) < 0)
 286                         log_fatal ("Can't fork daemon: %m");
 287                 else if (pid)
 288                         exit (0);
 289         }
 290
 291         /* Read previous pid file. */
 292         if ((i = open (path_dhcpd_pid, O_RDONLY)) >= 0) {
 293                 status = read (i, pbuf, (sizeof pbuf) - 1);
 294                 close (i);
 295                 pbuf [status] = 0;
 296                 pid = atoi (pbuf);
 297
 298                 /* If the previous server process is not still running,
 299                    write a new pid file immediately. */
 300                 if (pid && (pid == getpid() || kill (pid, 0) < 0)) {
 301                         unlink (path_dhcpd_pid);
 302                         if ((i = open (path_dhcpd_pid,
 303                                        O_WRONLY | O_CREAT, 0640)) >= 0) {
 304                                 sprintf (pbuf, "%d\n", (int)getpid ());
 305                                 write (i, pbuf, strlen (pbuf));
 306                                 close (i);
 307                                 pidfilewritten = 1;
 308                         }
 309                 } else
 310                         log_fatal ("There's already a DHCP server running.\n");
 311         }
 312
 313         /* If we were requested to log to stdout on the command line,
 314            keep doing so; otherwise, stop. */
 315         if (log_perror == -1)
 316                 log_perror = 1;
 317         else
 318                 log_perror = 0;
 319
 320         if (daemon) {
 321                 /* Become session leader and get pid... */
 322                 close (0);
 323                 close (1);
 324                 close (2);
 325                 pid = setsid ();
 326         }
 327
 328         /* If we didn't write the pid file earlier because we found a
 329            process running the logged pid, but we made it to here,
 330            meaning nothing is listening on the bootp port, then write
 331            the pid file out - what's in it now is bogus anyway. */
 332         if (!pidfilewritten) {
 333                 unlink (path_dhcpd_pid);
 334                 if ((i = open (path_dhcpd_pid,
 335                                O_WRONLY | O_CREAT, 0640)) >= 0) {
 336                         sprintf (pbuf, "%d\n", (int)getpid ());
 337                         write (i, pbuf, strlen (pbuf));
 338                         close (i);
 339                         pidfilewritten = 1;
 340                 }
 341         }
 342 #endif /* !DEBUG */
 343
 344         /* Set up the bootp packet handler... */
 345         bootp_packet_handler = do_packet;
 346
 347         /* Receive packets and dispatch them... */
 348         dispatch ();
 349
 350         /* Not reached */
 351         return 0;
 352 }
 353
 354 /* Print usage message. */
 355
 356 static void usage ()
 357 {
 358         log_info (message);
 359         log_info (copyright);
 360         log_info (arr);
 361
 362         log_fatal ("Usage: dhcpd [-p <UDP port #>] [-d] [-f] [-cf config-file]%s",
 363                "\n            [-lf lease-file] [if0 [...ifN]]");
 364 }
 365
 366 void cleanup ()
 367 {
 368 }
 369
 370 void lease_pinged (from, packet, length)
 371         struct iaddr from;
 372         u_int8_t *packet;
 373         int length;
 374 {
 375         struct lease *lp;
 376
 377         /* Don't try to look up a pinged lease if we aren't trying to
 378            ping one - otherwise somebody could easily make us churn by
 379            just forging repeated ICMP EchoReply packets for us to look
 380            up. */
 381         if (!outstanding_pings)
 382                 return;
 383
 384         lp = find_lease_by_ip_addr (from);
 385
 386         if (!lp) {
 387                 log_info ("unexpected ICMP Echo Reply from %s", piaddr (from));
 388                 return;
 389         }
 390
 391         if (!lp -> state) {
 392                 log_error ("ICMP Echo Reply for %s arrived late or is spurious.\n",
 393                       piaddr (from));
 394                 return;
 395         }
 396
 397         if (lp -> ends > cur_time) {
 398                 log_error ("ICMP Echo reply arrived while lease %s was valid.\n",
 399                       piaddr (from));
 400         }
 401
 402         /* At this point it looks like we pinged a lease and got a
 403            response, which shouldn't have happened. */
 404         data_string_forget (&lp -> state -> parameter_request_list,
 405                             "lease_pinged");
 406         free_lease_state (lp -> state, "lease_pinged");
 407         lp -> state = (struct lease_state *)0;
 408
 409         abandon_lease (lp, "pinged before offer");
 410         cancel_timeout (lease_ping_timeout, lp);
 411         --outstanding_pings;
 412 }
 413
 414 void lease_ping_timeout (vlp)
 415         void *vlp;
 416 {
 417         struct lease *lp = vlp;
 418
 419         --outstanding_pings;
 420         dhcp_reply (lp);
 421 }