contrib/dhcp-3.0/server/bootp.c

   1 /* bootp.c
   2
   3    BOOTP Protocol support. */
   4
   5 /*
   6  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   7  * Copyright (c) 1995-2003 by Internet Software Consortium
   8  *
   9  * Permission to use, copy, modify, and distribute this software for any
  10  * purpose with or without fee is hereby granted, provided that the above
  11  * copyright notice and this permission notice appear in all copies.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  19  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20  *
  21  *   Internet Systems Consortium, Inc.
  22  *   950 Charter Street
  23  *   Redwood City, CA 94063
  24  *   <info@isc.org>
  25  *   http://www.isc.org/
  26  *
  27  * This software has been written for Internet Systems Consortium
  28  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
  29  * To learn more about Internet Systems Consortium, see
  30  * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
  31  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
  32  * ``http://www.nominum.com''.
  33  */
  34
  35 #ifndef lint
  36 static char copyright[] =
  37 "$Id: bootp.c,v 1.69.2.8 2004/09/01 17:06:36 dhankins Exp $ Copyright (c) 2004 Internet Systems Consortium.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #include "dhcpd.h"
  41
  42 #if defined (TRACING)
  43 # define send_packet trace_packet_send
  44 #endif
  45
  46 void bootp (packet)
  47         struct packet *packet;
  48 {
  49         int result;
  50         struct host_decl *hp = (struct host_decl *)0;
  51         struct host_decl *host = (struct host_decl *)0;
  52         struct packet outgoing;
  53         struct dhcp_packet raw;
  54         struct sockaddr_in to;
  55         struct in_addr from;
  56         struct hardware hto;
  57         struct option_state *options = (struct option_state *)0;
  58         struct subnet *subnet;
  59         struct lease *lease;
  60         struct iaddr ip_address;
  61         unsigned i;
  62         struct data_string d1;
  63         struct option_cache *oc;
  64         char msgbuf [1024];
  65         int ignorep;
  66         int peer_has_leases = 0;
  67
  68         if (packet -> raw -> op != BOOTREQUEST)
  69                 return;
  70
  71         /* %Audit% This is log output. %2004.06.17,Safe%
  72          * If we truncate we hope the user can get a hint from the log.
  73          */
  74         snprintf (msgbuf, sizeof msgbuf, "BOOTREQUEST from %s via %s",
  75                  print_hw_addr (packet -> raw -> htype,
  76                                 packet -> raw -> hlen,
  77                                 packet -> raw -> chaddr),
  78                  packet -> raw -> giaddr.s_addr
  79                  ? inet_ntoa (packet -> raw -> giaddr)
  80                  : packet -> interface -> name);
  81
  82
  83
  84         if (!locate_network (packet)) {
  85                 log_info ("%s: network unknown", msgbuf);
  86                 return;
  87         }
  88
  89         find_hosts_by_haddr (&hp, packet -> raw -> htype,
  90                              packet -> raw -> chaddr,
  91                              packet -> raw -> hlen, MDL);
  92
  93         lease  = (struct lease *)0;
  94         find_lease (&lease, packet, packet -> shared_network,
  95                     0, 0, (struct lease *)0, MDL);
  96
  97         /* Find an IP address in the host_decl that matches the
  98            specified network. */
  99         subnet = (struct subnet *)0;
 100         if (hp)
 101                 find_host_for_network (&subnet, &hp, &ip_address,
 102                                        packet -> shared_network);
 103
 104         if (!subnet) {
 105                 struct host_decl *h;
 106                 /* We didn't find an applicable host declaration.
 107                    Just in case we may be able to dynamically assign
 108                    an address, see if there's a host declaration
 109                    that doesn't have an ip address associated with it. */
 110                 for (h = hp; h; h = h -> n_ipaddr) {
 111                         if (!h -> fixed_addr) {
 112                                 host_reference (&host, h, MDL);
 113                                 break;
 114                         }
 115                 }
 116                 if (hp) {
 117                         host_dereference (&hp, MDL);
 118                         if (host)
 119                                 host_reference (&hp, host, MDL);
 120                 }
 121
 122                 /* If a lease has already been assigned to this client,
 123                    use it. */
 124                 if (lease) {
 125                         if (host && host != lease -> host) {
 126                                 if (lease -> host)
 127                                         host_dereference (&lease -> host, MDL);
 128                                 host_reference (&lease -> host, host, MDL);
 129                         }
 130                         ack_lease (packet, lease, 0, 0, msgbuf, 0);
 131                         goto out;
 132                 }
 133
 134                 /* Otherwise, try to allocate one. */
 135                 allocate_lease (&lease, packet,
 136                                 packet -> shared_network -> pools,
 137                                 &peer_has_leases);
 138                 if (lease) {
 139                         if (host && host != lease -> host) {
 140                                 if (lease -> host)
 141                                         host_dereference (&lease -> host, MDL);
 142                                 host_reference (&lease -> host, host, MDL);
 143                         } else if (lease -> host)
 144                                 host_dereference (&lease -> host, MDL);
 145                         ack_lease (packet, lease, 0, 0, msgbuf, 0);
 146                         goto out;
 147                 }
 148
 149                 /* We couldn't find an address to give this bootp client. */
 150                 log_info ("%s: BOOTP from unknown client and no dynamic leases",
 151                         msgbuf);
 152                 goto out;
 153         }
 154
 155         /* Run the executable statements to compute the client and server
 156            options. */
 157         option_state_allocate (&options, MDL);
 158
 159         /* Execute the subnet statements. */
 160         execute_statements_in_scope ((struct binding_value **)0,
 161                                      packet, lease, (struct client_state *)0,
 162                                      packet -> options, options,
 163                                      &lease -> scope, lease -> subnet -> group,
 164                                      (struct group *)0);
 165
 166         /* Execute statements from class scopes. */
 167         for (i = packet -> class_count; i > 0; i--) {
 168                 execute_statements_in_scope
 169                         ((struct binding_value **)0,
 170                          packet, lease, (struct client_state *)0,
 171                          packet -> options, options,
 172                          &lease -> scope, packet -> classes [i - 1] -> group,
 173                          lease -> subnet -> group);
 174         }
 175
 176         /* Execute the host statements. */
 177         execute_statements_in_scope ((struct binding_value **)0,
 178                                      packet, lease, (struct client_state *)0,
 179                                      packet -> options, options,
 180                                      &lease -> scope,
 181                                      hp -> group, subnet -> group);
 182
 183         /* Drop the request if it's not allowed for this client. */
 184         if ((oc = lookup_option (&server_universe, options, SV_ALLOW_BOOTP)) &&
 185             !evaluate_boolean_option_cache (&ignorep, packet, lease,
 186                                             (struct client_state *)0,
 187                                             packet -> options, options,
 188                                             &lease -> scope, oc, MDL)) {
 189                 if (!ignorep)
 190                         log_info ("%s: bootp disallowed", msgbuf);
 191                 goto out;
 192         }
 193
 194         if ((oc = lookup_option (&server_universe,
 195                                  options, SV_ALLOW_BOOTING)) &&
 196             !evaluate_boolean_option_cache (&ignorep, packet, lease,
 197                                             (struct client_state *)0,
 198                                             packet -> options, options,
 199                                             &lease -> scope, oc, MDL)) {
 200                 if (!ignorep)
 201                         log_info ("%s: booting disallowed", msgbuf);
 202                 goto out;
 203         }
 204
 205         /* Set up the outgoing packet... */
 206         memset (&outgoing, 0, sizeof outgoing);
 207         memset (&raw, 0, sizeof raw);
 208         outgoing.raw = &raw;
 209
 210         /* If we didn't get a known vendor magic number on the way in,
 211            just copy the input options to the output. */
 212         if (!packet -> options_valid &&
 213             !(evaluate_boolean_option_cache
 214               (&ignorep, packet, lease, (struct client_state *)0,
 215                packet -> options, options, &lease -> scope,
 216                lookup_option (&server_universe, options,
 217                               SV_ALWAYS_REPLY_RFC1048), MDL))) {
 218                 memcpy (outgoing.raw -> options,
 219                         packet -> raw -> options, DHCP_OPTION_LEN);
 220                 outgoing.packet_length = BOOTP_MIN_LEN;
 221         } else {
 222
 223                 /* Use the subnet mask from the subnet declaration if no other
 224                    mask has been provided. */
 225
 226                 oc = (struct option_cache *)0;
 227                 i = DHO_SUBNET_MASK;
 228                 if (!lookup_option (&dhcp_universe, options, i)) {
 229                         if (option_cache_allocate (&oc, MDL)) {
 230                                 if (make_const_data
 231                                     (&oc -> expression,
 232                                      lease -> subnet -> netmask.iabuf,
 233                                      lease -> subnet -> netmask.len,
 234                                      0, 0, MDL)) {
 235                                         oc -> option =
 236                                                 dhcp_universe.options [i];
 237                                         save_option (&dhcp_universe,
 238                                                      options, oc);
 239                                 }
 240                                 option_cache_dereference (&oc, MDL);
 241                         }
 242                 }
 243
 244                 /* Pack the options into the buffer.  Unlike DHCP, we
 245                    can't pack options into the filename and server
 246                    name buffers. */
 247
 248                 outgoing.packet_length =
 249                         cons_options (packet, outgoing.raw, lease,
 250                                       (struct client_state *)0, 0,
 251                                       packet -> options, options,
 252                                       &lease -> scope,
 253                                       0, 0, 1, (struct data_string *)0,
 254                                       (const char *)0);
 255                 if (outgoing.packet_length < BOOTP_MIN_LEN)
 256                         outgoing.packet_length = BOOTP_MIN_LEN;
 257         }
 258
 259         /* Take the fields that we care about... */
 260         raw.op = BOOTREPLY;
 261         raw.htype = packet -> raw -> htype;
 262         raw.hlen = packet -> raw -> hlen;
 263         memcpy (raw.chaddr, packet -> raw -> chaddr, sizeof raw.chaddr);
 264         raw.hops = packet -> raw -> hops;
 265         raw.xid = packet -> raw -> xid;
 266         raw.secs = packet -> raw -> secs;
 267         raw.flags = packet -> raw -> flags;
 268         raw.ciaddr = packet -> raw -> ciaddr;
 269         memcpy (&raw.yiaddr, ip_address.iabuf, sizeof raw.yiaddr);
 270
 271         /* If we're always supposed to broadcast to this client, set
 272            the broadcast bit in the bootp flags field. */
 273         if ((oc = lookup_option (&server_universe,
 274                                 options, SV_ALWAYS_BROADCAST)) &&
 275             evaluate_boolean_option_cache (&ignorep, packet, lease,
 276                                            (struct client_state *)0,
 277                                            packet -> options, options,
 278                                            &lease -> scope, oc, MDL))
 279                 raw.flags |= htons (BOOTP_BROADCAST);
 280
 281         /* Figure out the address of the next server. */
 282         memset (&d1, 0, sizeof d1);
 283         oc = lookup_option (&server_universe, options, SV_NEXT_SERVER);
 284         if (oc &&
 285             evaluate_option_cache (&d1, packet, lease,
 286                                    (struct client_state *)0,
 287                                    packet -> options, options,
 288                                    &lease -> scope, oc, MDL)) {
 289                 /* If there was more than one answer, take the first. */
 290                 if (d1.len >= 4 && d1.data)
 291                         memcpy (&raw.siaddr, d1.data, 4);
 292                 data_string_forget (&d1, MDL);
 293         } else {
 294                 if (lease -> subnet -> shared_network -> interface)
 295                         raw.siaddr = (lease -> subnet -> shared_network ->
 296                                       interface -> primary_address);
 297                 else
 298                         raw.siaddr = packet -> interface -> primary_address;
 299         }
 300
 301         raw.giaddr = packet -> raw -> giaddr;
 302
 303         /* Figure out the filename. */
 304         oc = lookup_option (&server_universe, options, SV_FILENAME);
 305         if (oc &&
 306             evaluate_option_cache (&d1, packet, lease,
 307                                    (struct client_state *)0,
 308                                    packet -> options, options,
 309                                    &lease -> scope, oc, MDL)) {
 310                 memcpy (raw.file, d1.data,
 311                         d1.len > sizeof raw.file ? sizeof raw.file : d1.len);
 312                 if (sizeof raw.file > d1.len)
 313                         memset (&raw.file [d1.len],
 314                                 0, (sizeof raw.file) - d1.len);
 315                 data_string_forget (&d1, MDL);
 316         } else
 317                 memcpy (raw.file, packet -> raw -> file, sizeof raw.file);
 318
 319         /* Choose a server name as above. */
 320         oc = lookup_option (&server_universe, options, SV_SERVER_NAME);
 321         if (oc &&
 322             evaluate_option_cache (&d1, packet, lease,
 323                                    (struct client_state *)0,
 324                                    packet -> options, options,
 325                                    &lease -> scope, oc, MDL)) {
 326                 memcpy (raw.sname, d1.data,
 327                         d1.len > sizeof raw.sname ? sizeof raw.sname : d1.len);
 328                 if (sizeof raw.sname > d1.len)
 329                         memset (&raw.sname [d1.len],
 330                                 0, (sizeof raw.sname) - d1.len);
 331                 data_string_forget (&d1, MDL);
 332         }
 333
 334         /* Execute the commit statements, if there are any. */
 335         execute_statements ((struct binding_value **)0,
 336                             packet, lease, (struct client_state *)0,
 337                             packet -> options,
 338                             options, &lease -> scope, lease -> on_commit);
 339
 340         /* We're done with the option state. */
 341         option_state_dereference (&options, MDL);
 342
 343         /* Set up the hardware destination address... */
 344         hto.hbuf [0] = packet -> raw -> htype;
 345         hto.hlen = packet -> raw -> hlen + 1;
 346         memcpy (&hto.hbuf [1], packet -> raw -> chaddr, packet -> raw -> hlen);
 347
 348         from = packet -> interface -> primary_address;
 349
 350         /* Report what we're doing... */
 351         log_info ("%s", msgbuf);
 352         log_info ("BOOTREPLY for %s to %s (%s) via %s",
 353               piaddr (ip_address), hp -> name,
 354               print_hw_addr (packet -> raw -> htype,
 355                              packet -> raw -> hlen,
 356                              packet -> raw -> chaddr),
 357               packet -> raw -> giaddr.s_addr
 358               ? inet_ntoa (packet -> raw -> giaddr)
 359               : packet -> interface -> name);
 360
 361         /* Set up the parts of the address that are in common. */
 362         to.sin_family = AF_INET;
 363 #ifdef HAVE_SA_LEN
 364         to.sin_len = sizeof to;
 365 #endif
 366         memset (to.sin_zero, 0, sizeof to.sin_zero);
 367
 368         /* If this was gatewayed, send it back to the gateway... */
 369         if (raw.giaddr.s_addr) {
 370                 to.sin_addr = raw.giaddr;
 371                 to.sin_port = local_port;
 372
 373                 if (fallback_interface) {
 374                         result = send_packet (fallback_interface,
 375                                               (struct packet *)0,
 376                                               &raw, outgoing.packet_length,
 377                                               from, &to, &hto);
 378                         goto out;
 379                 }
 380
 381         /* If it comes from a client that already knows its address
 382            and is not requesting a broadcast response, and we can
 383            unicast to a client without using the ARP protocol, sent it
 384            directly to that client. */
 385         } else if (!(raw.flags & htons (BOOTP_BROADCAST)) &&
 386                    can_unicast_without_arp (packet -> interface)) {
 387                 to.sin_addr = raw.yiaddr;
 388                 to.sin_port = remote_port;
 389
 390         /* Otherwise, broadcast it on the local network. */
 391         } else {
 392                 to.sin_addr = limited_broadcast;
 393                 to.sin_port = remote_port; /* XXX */
 394         }
 395
 396         errno = 0;
 397         result = send_packet (packet -> interface,
 398                               packet, &raw, outgoing.packet_length,
 399                               from, &to, &hto);
 400       out:
 401         if (options)
 402                 option_state_dereference (&options, MDL);
 403         if (lease)
 404                 lease_dereference (&lease, MDL);
 405         if (hp)
 406                 host_dereference (&hp, MDL);
 407         if (host)
 408                 host_dereference (&host, MDL);
 409         if (subnet)
 410                 subnet_dereference (&subnet, MDL);
 411 }