common/upf.c

   1 /* upf.c
   2
   3    Ultrix PacketFilter interface code. */
   4
   5 /*
   6  * Copyright (c) 1996-2000 Internet Software Consortium.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of The Internet Software Consortium nor the names
  19  *    of its contributors may be used to endorse or promote products derived
  20  *    from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
  23  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  24  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  26  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
  27  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  29  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  30  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * This software has been written for the Internet Software Consortium
  37  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
  38  * To learn more about the Internet Software Consortium, see
  39  * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
  40  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
  41  * ``http://www.nominum.com''.
  42  */
  43
  44 #ifndef lint
  45 static char copyright[] =
  46 "$Id: upf.c,v 1.17 2000/03/17 03:59:02 mellon Exp $ Copyright (c) 1996-2000 The Internet Software Consortium.  All rights reserved.\n";
  47 #endif /* not lint */
  48
  49 #include "dhcpd.h"
  50 #if defined (USE_UPF_SEND) || defined (USE_UPF_RECEIVE)
  51 #include <sys/ioctl.h>
  52 #include <sys/uio.h>
  53
  54 #include <net/pfilt.h>
  55 #include <netinet/in_systm.h>
  56 #include "includes/netinet/ip.h"
  57 #include "includes/netinet/udp.h"
  58 #include "includes/netinet/if_ether.h"
  59
  60 /* Reinitializes the specified interface after an address change.   This
  61    is not required for packet-filter APIs. */
  62
  63 #ifdef USE_UPF_SEND
  64 void if_reinitialize_send (info)
  65         struct interface_info *info;
  66 {
  67 }
  68 #endif
  69
  70 #ifdef USE_UPF_RECEIVE
  71 void if_reinitialize_receive (info)
  72         struct interface_info *info;
  73 {
  74 }
  75 #endif
  76
  77 /* Called by get_interface_list for each interface that's discovered.
  78    Opens a packet filter for each interface and adds it to the select
  79    mask. */
  80
  81 int if_register_upf (info)
  82         struct interface_info *info;
  83 {
  84         int sock;
  85         char filename[50];
  86         int b;
  87         struct endevp param;
  88
  89         /* Open a UPF device */
  90         for (b = 0; 1; b++) {
  91 #ifndef NO_SNPRINTF
  92                 snprintf(filename, sizeof(filename), "/dev/pf/pfilt%d", b);
  93 #else
  94                 sprintf(filename, "/dev/pf/pfilt%d", b);
  95 #endif
  96                 sock = open (filename, O_RDWR, 0);
  97                 if (sock < 0) {
  98                         if (errno == EBUSY) {
  99                                 continue;
 100                         } else {
 101                                 log_fatal ("Can't find free upf: %m");
 102                         }
 103                 } else {
 104                         break;
 105                 }
 106         }
 107
 108         /* Set the UPF device to point at this interface. */
 109         if (ioctl (sock, EIOCSETIF, info -> ifp) < 0)
 110                 log_fatal ("Can't attach interface %s to upf device %s: %m",
 111                        info -> name, filename);
 112
 113         /* Get the hardware address. */
 114         if (ioctl (sock, EIOCDEVP, &param) < 0)
 115                 log_fatal ("Can't get interface %s hardware address: %m",
 116                        info -> name);
 117
 118         /* We only know how to do ethernet. */
 119         if (param.end_dev_type != ENDT_10MB)
 120                 log_fatal ("Invalid device type on network interface %s: %d",
 121                        info -> name, param.end_dev_type);
 122
 123         if (param.end_addr_len != 6)
 124                 log_fatal ("Invalid hardware address length on %s: %d",
 125                        info -> name, param.end_addr_len);
 126
 127         info -> hw_address.hlen = 7;
 128         info -> hw_address.hbuf [0] = ARPHRD_ETHER;
 129         memcpy (&info -> hw_address.hbuf [1], param.end_addr, 6);
 130
 131         return sock;
 132 }
 133 #endif /* USE_UPF_SEND || USE_UPF_RECEIVE */
 134
 135 #ifdef USE_UPF_SEND
 136 void if_register_send (info)
 137         struct interface_info *info;
 138 {
 139         /* If we're using the upf API for sending and receiving,
 140            we don't need to register this interface twice. */
 141 #ifndef USE_UPF_RECEIVE
 142         info -> wfdesc = if_register_upf (info, interface);
 143 #else
 144         info -> wfdesc = info -> rfdesc;
 145 #endif
 146         if (!quiet_interface_discovery)
 147                 log_info ("Sending on   UPF/%s/%s%s%s",
 148                       info -> name,
 149                       print_hw_addr (info -> hw_address.hbuf [0],
 150                                      info -> hw_address.hlen - 1,
 151                                      &info -> hw_address.hbuf [1]),
 152                       (info -> shared_network ? "/" : ""),
 153                       (info -> shared_network ?
 154                        info -> shared_network -> name : ""));
 155 }
 156
 157 void if_deregister_send (info)
 158         struct interface_info *info;
 159 {
 160 #ifndef USE_UPF_RECEIVE
 161         close (info -> wfdesc);
 162 #endif
 163         info -> wfdesc = -1;
 164         if (!quiet_interface_discovery)
 165                 log_info ("Disabling output on UPF/%s/%s%s%s",
 166                       info -> name,
 167                       print_hw_addr (info -> hw_address.hbuf [0],
 168                                      info -> hw_address.hlen - 1,
 169                                      &info -> hw_address.hbuf [1]),
 170                       (info -> shared_network ? "/" : ""),
 171                       (info -> shared_network ?
 172                        info -> shared_network -> name : ""));
 173 }
 174 #endif /* USE_UPF_SEND */
 175
 176 #ifdef USE_UPF_RECEIVE
 177 /* Packet filter program...
 178    XXX Changes to the filter program may require changes to the constant
 179    offsets used in if_register_send to patch the UPF program! XXX */
 180
 181
 182 void if_register_receive (info)
 183         struct interface_info *info;
 184 {
 185         int flag = 1;
 186         u_int32_t addr;
 187         struct enfilter pf;
 188         u_int32_t bits;
 189
 190         /* Open a UPF device and hang it on this interface... */
 191         info -> rfdesc = if_register_upf (info);
 192
 193         /* Allow the copyall flag to be set... */
 194         if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
 195                 log_fatal ("Can't set ALLOWCOPYALL: %m");
 196
 197         /* Clear all the packet filter mode bits first... */
 198         flag = (ENHOLDSIG | ENBATCH | ENTSTAMP | ENPROMISC |
 199                 ENNONEXCL | ENCOPYALL);
 200         if (ioctl (info -> rfdesc, EIOCMBIC, &flag) < 0)
 201                 log_fatal ("Can't clear pfilt bits: %m");
 202
 203         /* Set the ENBATCH and ENCOPYALL bits... */
 204         bits = ENBATCH | ENCOPYALL;
 205         if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
 206                 log_fatal ("Can't set ENBATCH|ENCOPYALL: %m");
 207
 208         /* Set up the UPF filter program. */
 209         /* XXX Unlike the BPF filter program, this one won't work if the
 210            XXX IP packet is fragmented or if there are options on the IP
 211            XXX header. */
 212         pf.enf_Priority = 0;
 213         pf.enf_FilterLen = 0;
 214
 215         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 6;
 216         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
 217         pf.enf_Filter [pf.enf_FilterLen++] = htons (ETHERTYPE_IP);
 218         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT;
 219         pf.enf_Filter [pf.enf_FilterLen++] = htons (IPPROTO_UDP);
 220         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 11;
 221         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
 222         pf.enf_Filter [pf.enf_FilterLen++] = htons (0xFF);
 223         pf.enf_Filter [pf.enf_FilterLen++] = ENF_CAND;
 224         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHWORD + 18;
 225         pf.enf_Filter [pf.enf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
 226         pf.enf_Filter [pf.enf_FilterLen++] = local_port;
 227
 228         if (ioctl (info -> rfdesc, EIOCSETF, &pf) < 0)
 229                 log_fatal ("Can't install packet filter program: %m");
 230         if (!quiet_interface_discovery)
 231                 log_info ("Listening on UPF/%s/%s%s%s",
 232                       info -> name,
 233                       print_hw_addr (info -> hw_address.hbuf [0],
 234                                      info -> hw_address.hlen - 1,
 235                                      &info -> hw_address.hbuf [1]),
 236                       (info -> shared_network ? "/" : ""),
 237                       (info -> shared_network ?
 238                        info -> shared_network -> name : ""));
 239 }
 240
 241 void if_deregister_receive (info)
 242         struct interface_info *info;
 243 {
 244         close (info -> rfdesc);
 245         info -> rfdesc = -1;
 246         if (!quiet_interface_discovery)
 247                 log_info ("Disabling input on UPF/%s/%s%s%s",
 248                       info -> name,
 249                       print_hw_addr (info -> hw_address.hbuf [0],
 250                                      info -> hw_address.hlen - 1,
 251                                      &info -> hw_address.hbuf [1]),
 252                       (info -> shared_network ? "/" : ""),
 253                       (info -> shared_network ?
 254                        info -> shared_network -> name : ""));
 255 }
 256 #endif /* USE_UPF_RECEIVE */
 257
 258 #ifdef USE_UPF_SEND
 259 ssize_t send_packet (interface, packet, raw, len, from, to, hto)
 260         struct interface_info *interface;
 261         struct packet *packet;
 262         struct dhcp_packet *raw;
 263         size_t len;
 264         struct in_addr from;
 265         struct sockaddr_in *to;
 266         struct hardware *hto;
 267 {
 268         unsigned bufp = 0;
 269         unsigned char buf [256];
 270         struct iovec iov [2];
 271         int result;
 272
 273         if (!strcmp (interface -> name, "fallback"))
 274                 return send_fallback (interface, packet, raw,
 275                                       len, from, to, hto);
 276
 277         /* Assemble the headers... */
 278         assemble_hw_header (interface, buf, &bufp, hto);
 279         assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
 280                                 to -> sin_addr.s_addr, to -> sin_port,
 281                                 (unsigned char *)raw, len);
 282
 283         /* Fire it off */
 284         iov [0].iov_base = (char *)buf;
 285         iov [0].iov_len = bufp;
 286         iov [1].iov_base = (char *)raw;
 287         iov [1].iov_len = len;
 288
 289         result = writev(interface -> wfdesc, iov, 2);
 290         if (result < 0)
 291                 log_error ("send_packet: %m");
 292         return result;
 293 }
 294 #endif /* USE_UPF_SEND */
 295
 296 #ifdef USE_UPF_RECEIVE
 297 ssize_t receive_packet (interface, buf, len, from, hfrom)
 298         struct interface_info *interface;
 299         unsigned char *buf;
 300         size_t len;
 301         struct sockaddr_in *from;
 302         struct hardware *hfrom;
 303 {
 304         int nread;
 305         int length = 0;
 306         int offset = 0;
 307         unsigned char ibuf [1500 + sizeof (struct enstamp)];
 308         int bufix = 0;
 309
 310         length = read (interface -> rfdesc, ibuf, sizeof ibuf);
 311         if (length <= 0)
 312                 return length;
 313
 314         bufix = sizeof (struct enstamp);
 315         /* Decode the physical header... */
 316         offset = decode_hw_header (interface, ibuf, bufix, hfrom);
 317
 318         /* If a physical layer checksum failed (dunno of any
 319            physical layer that supports this, but WTH), skip this
 320            packet. */
 321         if (offset < 0) {
 322                 return 0;
 323         }
 324
 325         bufix += offset;
 326         length -= offset;
 327
 328         /* Decode the IP and UDP headers... */
 329         offset = decode_udp_ip_header (interface, ibuf, bufix,
 330                                        from, (unsigned char *)0, length);
 331
 332         /* If the IP or UDP checksum was bad, skip the packet... */
 333         if (offset < 0)
 334                 return 0;
 335
 336         bufix += offset;
 337         length -= offset;
 338
 339         /* Copy out the data in the packet... */
 340         memcpy (buf, &ibuf [bufix], length);
 341         return length;
 342 }
 343
 344 int can_unicast_without_arp (ip)
 345         struct interface_info *ip;
 346 {
 347         return 1;
 348 }
 349
 350 int can_receive_unicast_unconfigured (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;
 360         fbi = setup_fallback ();
 361         if (fbi) {
 362                 if_register_fallback (fbi);
 363                 fbi -> refcnt = 1;
 364                 fbi -> type = dhcp_type_interface;
 365                 status = omapi_register_io_object ((omapi_object_t *)fbi,
 366                                                    if_readsocket, 0,
 367                                                    fallback_discard, 0, 0);
 368                 if (status != ISC_R_SUCCESS)
 369                         log_fatal ("Can't register I/O handle for %s: %s",
 370                                    fbi -> name, isc_result_totext (status));
 371         }
 372 }
 373 #endif