contrib/dhcp-3.0/common/upf.c

   1 /* upf.c
   2
   3    Ultrix PacketFilter interface code. */
   4
   5 /*
   6  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   7  * Copyright (c) 1996-2003 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: upf.c,v 1.21.2.5 2004/11/24 17:39:16 dhankins Exp $ Copyright (c) 2004 Internet Systems Consortium.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #include "dhcpd.h"
  41 #if defined (USE_UPF_SEND) || defined (USE_UPF_RECEIVE)
  42 #include <sys/ioctl.h>
  43 #include <sys/uio.h>
  44
  45 #include <net/pfilt.h>
  46 #include <netinet/in_systm.h>
  47 #include "includes/netinet/ip.h"
  48 #include "includes/netinet/udp.h"
  49 #include "includes/netinet/if_ether.h"
  50
  51 /* Reinitializes the specified interface after an address change.   This
  52    is not required for packet-filter APIs. */
  53
  54 #ifdef USE_UPF_SEND
  55 void if_reinitialize_send (info)
  56         struct interface_info *info;
  57 {
  58 }
  59 #endif
  60
  61 #ifdef USE_UPF_RECEIVE
  62 void if_reinitialize_receive (info)
  63         struct interface_info *info;
  64 {
  65 }
  66 #endif
  67
  68 /* Called by get_interface_list for each interface that's discovered.
  69    Opens a packet filter for each interface and adds it to the select
  70    mask. */
  71
  72 int if_register_upf (info)
  73         struct interface_info *info;
  74 {
  75         int sock;
  76         char filename[50];
  77         int b;
  78         struct endevp param;
  79
  80         /* Open a UPF device */
  81         for (b = 0; 1; b++) {
  82                 /* %Audit% Cannot exceed 36 bytes. %2004.06.17,Safe% */
  83                 sprintf(filename, "/dev/pf/pfilt%d", b);
  84
  85                 sock = open (filename, O_RDWR, 0);
  86                 if (sock < 0) {
  87                         if (errno == EBUSY) {
  88                                 continue;
  89                         } else {
  90                                 log_fatal ("Can't find free upf: %m");
  91                         }
  92                 } else {
  93                         break;
  94                 }
  95         }
  96
  97         /* Set the UPF device to point at this interface. */
  98         if (ioctl (sock, EIOCSETIF, info -> ifp) < 0)
  99                 log_fatal ("Can't attach interface %s to upf device %s: %m",
 100                        info -> name, filename);
 101
 102         /* Get the hardware address. */
 103         if (ioctl (sock, EIOCDEVP, &param) < 0)
 104                 log_fatal ("Can't get interface %s hardware address: %m",
 105                        info -> name);
 106
 107         /* We only know how to do ethernet. */
 108         if (param.end_dev_type != ENDT_10MB)
 109                 log_fatal ("Invalid device type on network interface %s: %d",
 110                        info -> name, param.end_dev_type);
 111
 112         if (param.end_addr_len != 6)
 113                 log_fatal ("Invalid hardware address length on %s: %d",
 114                        info -> name, param.end_addr_len);
 115
 116         info -> hw_address.hlen = 7;
 117         info -> hw_address.hbuf [0] = ARPHRD_ETHER;
 118         memcpy (&info -> hw_address.hbuf [1], param.end_addr, 6);
 119
 120         return sock;
 121 }
 122 #endif /* USE_UPF_SEND || USE_UPF_RECEIVE */
 123
 124 #ifdef USE_UPF_SEND
 125 void if_register_send (info)
 126         struct interface_info *info;
 127 {
 128         /* If we're using the upf API for sending and receiving,
 129            we don't need to register this interface twice. */
 130 #ifndef USE_UPF_RECEIVE
 131         info -> wfdesc = if_register_upf (info, interface);
 132 #else
 133         info -> wfdesc = info -> rfdesc;
 134 #endif
 135         if (!quiet_interface_discovery)
 136                 log_info ("Sending on   UPF/%s/%s%s%s",
 137                       info -> name,
 138                       print_hw_addr (info -> hw_address.hbuf [0],
 139                                      info -> hw_address.hlen - 1,
 140                                      &info -> hw_address.hbuf [1]),
 141                       (info -> shared_network ? "/" : ""),
 142                       (info -> shared_network ?
 143                        info -> shared_network -> name : ""));
 144 }
 145
 146 void if_deregister_send (info)
 147         struct interface_info *info;
 148 {
 149 #ifndef USE_UPF_RECEIVE
 150         close (info -> wfdesc);
 151 #endif
 152         info -> wfdesc = -1;
 153         if (!quiet_interface_discovery)
 154                 log_info ("Disabling output on UPF/%s/%s%s%s",
 155                       info -> name,
 156                       print_hw_addr (info -> hw_address.hbuf [0],
 157                                      info -> hw_address.hlen - 1,
 158                                      &info -> hw_address.hbuf [1]),
 159                       (info -> shared_network ? "/" : ""),
 160                       (info -> shared_network ?
 161                        info -> shared_network -> name : ""));
 162 }
 163 #endif /* USE_UPF_SEND */
 164
 165 #ifdef USE_UPF_RECEIVE
 166 /* Packet filter program...
 167    XXX Changes to the filter program may require changes to the constant
 168    offsets used in if_register_send to patch the UPF program! XXX */
 169
 170
 171 void if_register_receive (info)
 172         struct interface_info *info;
 173 {
 174         int flag = 1;
 175         u_int32_t addr;
 176         struct enfilter pf;
 177         u_int32_t bits;
 178
 179         /* Open a UPF device and hang it on this interface... */
 180         info -> rfdesc = if_register_upf (info);
 181
 182         /* Allow the copyall flag to be set... */
 183         if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
 184                 log_fatal ("Can't set ALLOWCOPYALL: %m");
 185
 186         /* Clear all the packet filter mode bits first... */
 187         flag = (ENHOLDSIG | ENBATCH | ENTSTAMP | ENPROMISC |
 188                 ENNONEXCL | ENCOPYALL);
 189         if (ioctl (info -> rfdesc, EIOCMBIC, &flag) < 0)
 190                 log_fatal ("Can't clear pfilt bits: %m");
 191
 192         /* Set the ENBATCH and ENCOPYALL bits... */
 193         bits = ENBATCH | ENCOPYALL;
 194         if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
 195                 log_fatal ("Can't set ENBATCH|ENCOPYALL: %m");
 196
 197         /* Set up the UPF filter program. */
 198         /* XXX Unlike the BPF filter program, this one won't work if the
 199            XXX IP packet is fragmented or if there are options on the IP
 200            XXX header. */
 201         pf.enf_Priority = 0;
 202         pf.enf_FilterLen = 0;
 203
 204         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 6;
 205         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
 206         pf.enf_Filter [pf.enf_FilterLen++] = htons (ETHERTYPE_IP);
 207         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT;
 208         pf.enf_Filter [pf.enf_FilterLen++] = htons (IPPROTO_UDP);
 209         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 11;
 210         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
 211         pf.enf_Filter [pf.enf_FilterLen++] = htons (0xFF);
 212         pf.enf_Filter [pf.enf_FilterLen++] = ENF_CAND;
 213         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 18;
 214         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
 215         pf.enf_Filter [pf.enf_FilterLen++] = local_port;
 216
 217         if (ioctl (info -> rfdesc, EIOCSETF, &pf) < 0)
 218                 log_fatal ("Can't install packet filter program: %m");
 219         if (!quiet_interface_discovery)
 220                 log_info ("Listening on UPF/%s/%s%s%s",
 221                       info -> name,
 222                       print_hw_addr (info -> hw_address.hbuf [0],
 223                                      info -> hw_address.hlen - 1,
 224                                      &info -> hw_address.hbuf [1]),
 225                       (info -> shared_network ? "/" : ""),
 226                       (info -> shared_network ?
 227                        info -> shared_network -> name : ""));
 228 }
 229
 230 void if_deregister_receive (info)
 231         struct interface_info *info;
 232 {
 233         close (info -> rfdesc);
 234         info -> rfdesc = -1;
 235         if (!quiet_interface_discovery)
 236                 log_info ("Disabling input on UPF/%s/%s%s%s",
 237                       info -> name,
 238                       print_hw_addr (info -> hw_address.hbuf [0],
 239                                      info -> hw_address.hlen - 1,
 240                                      &info -> hw_address.hbuf [1]),
 241                       (info -> shared_network ? "/" : ""),
 242                       (info -> shared_network ?
 243                        info -> shared_network -> name : ""));
 244 }
 245 #endif /* USE_UPF_RECEIVE */
 246
 247 #ifdef USE_UPF_SEND
 248 ssize_t send_packet (interface, packet, raw, len, from, to, hto)
 249         struct interface_info *interface;
 250         struct packet *packet;
 251         struct dhcp_packet *raw;
 252         size_t len;
 253         struct in_addr from;
 254         struct sockaddr_in *to;
 255         struct hardware *hto;
 256 {
 257         unsigned hbufp = 0, ibufp = 0;
 258         double hw [4];
 259         double ip [32];
 260         struct iovec iov [3];
 261         int result;
 262         int fudge;
 263
 264         if (!strcmp (interface -> name, "fallback"))
 265                 return send_fallback (interface, packet, raw,
 266                                       len, from, to, hto);
 267
 268         /* Assemble the headers... */
 269         assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
 270         assemble_udp_ip_header (interface,
 271                                 (unsigned char *)ip, &ibufp, from.s_addr,
 272                                 to -> sin_addr.s_addr, to -> sin_port,
 273                                 (unsigned char *)raw, len);
 274
 275         /* Fire it off */
 276         iov [0].iov_base = ((char *)hw);
 277         iov [0].iov_len = hbufp;
 278         iov [1].iov_base = ((char *)ip);
 279         iov [1].iov_len = ibufp;
 280         iov [2].iov_base = (char *)raw;
 281         iov [2].iov_len = len;
 282
 283         result = writev(interface -> wfdesc, iov, 3);
 284         if (result < 0)
 285                 log_error ("send_packet: %m");
 286         return result;
 287 }
 288 #endif /* USE_UPF_SEND */
 289
 290 #ifdef USE_UPF_RECEIVE
 291 ssize_t receive_packet (interface, buf, len, from, hfrom)
 292         struct interface_info *interface;
 293         unsigned char *buf;
 294         size_t len;
 295         struct sockaddr_in *from;
 296         struct hardware *hfrom;
 297 {
 298         int nread;
 299         int length = 0;
 300         int offset = 0;
 301         unsigned char ibuf [1500 + sizeof (struct enstamp)];
 302         int bufix = 0;
 303
 304         length = read (interface -> rfdesc, ibuf, sizeof ibuf);
 305         if (length <= 0)
 306                 return length;
 307
 308         bufix = sizeof (struct enstamp);
 309         /* Decode the physical header... */
 310         offset = decode_hw_header (interface, ibuf, bufix, hfrom);
 311
 312         /* If a physical layer checksum failed (dunno of any
 313            physical layer that supports this, but WTH), skip this
 314            packet. */
 315         if (offset < 0) {
 316                 return 0;
 317         }
 318
 319         bufix += offset;
 320         length -= offset;
 321
 322         /* Decode the IP and UDP headers... */
 323         offset = decode_udp_ip_header (interface, ibuf, bufix,
 324                                        from, length);
 325
 326         /* If the IP or UDP checksum was bad, skip the packet... */
 327         if (offset < 0)
 328                 return 0;
 329
 330         bufix += offset;
 331         length -= offset;
 332
 333         /* Copy out the data in the packet... */
 334         memcpy (buf, &ibuf [bufix], length);
 335         return length;
 336 }
 337
 338 int can_unicast_without_arp (ip)
 339         struct interface_info *ip;
 340 {
 341         return 1;
 342 }
 343
 344 int can_receive_unicast_unconfigured (ip)
 345         struct interface_info *ip;
 346 {
 347         return 1;
 348 }
 349
 350 int supports_multiple_interfaces (ip)
 351         struct interface_info *ip;
 352 {
 353         return 1;
 354 }
 355
 356 void maybe_setup_fallback ()
 357 {
 358         isc_result_t status;
 359         struct interface_info *fbi = (struct interface_info *)0;
 360         if (setup_fallback (&fbi, MDL)) {
 361                 if_register_fallback (fbi);
 362                 status = omapi_register_io_object ((omapi_object_t *)fbi,
 363                                                    if_readsocket, 0,
 364                                                    fallback_discard, 0, 0);
 365                 if (status != ISC_R_SUCCESS)
 366                         log_fatal ("Can't register I/O handle for %s: %s",
 367                                    fbi -> name, isc_result_totext (status));
 368                 interface_dereference (&fbi, MDL);
 369         }
 370 }
 371 #endif