workbench/network/stacks/AROSTCP/dhcp/common/bpf.c

   1 /* bpf.c
   2
   3    BPF socket interface code, originally contributed by Archie Cobbs. */
   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 was contributed to Internet Systems Consortium
  28  * by Archie Cobbs.
  29  *
  30  * Patches for FDDI support on Digital Unix were written by Bill
  31  * Stapleton, and maintained for a while by Mike Meredith before he
  32  * managed to get me to integrate them.
  33  */
  34
  35 #if 0
  36 static char copyright[] =
  37 "$Id$ Copyright (c) 2004 Internet Systems Consortium.  All rights reserved.\n";
  38 #endif
  39
  40 #if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE) \
  41                                 || defined (USE_LPF_RECEIVE)
  42 # if defined (USE_LPF_RECEIVE)
  43 #  include "dhcpd.h"
  44 #  include <asm/types.h>
  45 #  include <linux/filter.h>
  46 #  define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
  47 # else
  48 /* This one's for BSD based OSes (dunno if it breaks any other OSes) */
  49 # define USE_SOCKET_FALLBACK
  50 #  include "dhcpd.h"
  51 #  include <sys/ioctl.h>
  52 #  include <sys/uio.h>
  53 #  include "/usr/include/net/bpf.h"
  54 #  if defined (NEED_OSF_PFILT_HACKS)
  55 #   include </usr/include/net/pfilt.h>
  56 #  endif
  57 # endif
  58
  59 #include <netinet/in_systm.h>
  60 #include "includes/netinet/ip.h"
  61 #include "includes/netinet/udp.h"
  62 #include "includes/netinet/if_ether.h"
  63 #endif
  64
  65 /* Reinitializes the specified interface after an address change.   This
  66    is not required for packet-filter APIs. */
  67
  68 #ifdef USE_BPF_SEND
  69 void if_reinitialize_send (info)
  70         struct interface_info *info;
  71 {
  72 }
  73 #endif
  74
  75 #ifdef USE_BPF_RECEIVE
  76 void if_reinitialize_receive (info)
  77         struct interface_info *info;
  78 {
  79 }
  80 #endif
  81
  82 /* Called by get_interface_list for each interface that's discovered.
  83    Opens a packet filter for each interface and adds it to the select
  84    mask. */
  85
  86 #if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)
  87 int if_register_bpf (info)
  88         struct interface_info *info;
  89 {
  90         int sock;
  91         char filename[50];
  92         int b;
  93
  94         /* Open a BPF device */
  95         for (b = 0; 1; b++) {
  96                 /* %Audit% 31 bytes max. %2004.06.17,Safe% */
  97                 sprintf(filename, BPF_FORMAT, b);
  98                 sock = open (filename, O_RDWR, 0);
  99                 if (sock < 0) {
 100                         if (errno == EBUSY) {
 101                                 continue;
 102                         } else {
 103                                 if (!b)
 104                                         log_fatal ("No bpf devices.%s%s%s",
 105                                                "   Please read the README",
 106                                                " section for your operating",
 107                                                " system.");
 108                                 log_fatal ("Can't find free bpf: %m");
 109                         }
 110                 } else {
 111                         break;
 112                 }
 113         }
 114
 115         /* Set the BPF device to point at this interface. */
 116         if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
 117                 log_fatal ("Can't attach interface %s to bpf device %s: %m",
 118                        info -> name, filename);
 119
 120         return sock;
 121 }
 122 #endif /* USE_BPF_SEND || USE_BPF_RECEIVE */
 123
 124 #ifdef USE_BPF_SEND
 125 void if_register_send (info)
 126         struct interface_info *info;
 127 {
 128         /* If we're using the bpf API for sending and receiving,
 129            we don't need to register this interface twice. */
 130 #ifndef USE_BPF_RECEIVE
 131         info -> wfdesc = if_register_bpf (info, interface);
 132 #else
 133         info -> wfdesc = info -> rfdesc;
 134 #endif
 135         if (!quiet_interface_discovery)
 136                 log_info ("Sending on   BPF/%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         /* If we're using the bpf API for sending and receiving,
 150            we don't need to register this interface twice. */
 151 #ifndef USE_BPF_RECEIVE
 152         close (info -> wfdesc);
 153 #endif
 154         info -> wfdesc = -1;
 155
 156         if (!quiet_interface_discovery)
 157                 log_info ("Disabling output on BPF/%s/%s%s%s",
 158                       info -> name,
 159                       print_hw_addr (info -> hw_address.hbuf [0],
 160                                      info -> hw_address.hlen - 1,
 161                                      &info -> hw_address.hbuf [1]),
 162                       (info -> shared_network ? "/" : ""),
 163                       (info -> shared_network ?
 164                        info -> shared_network -> name : ""));
 165 }
 166 #endif /* USE_BPF_SEND */
 167
 168 #if defined (USE_BPF_RECEIVE) || defined (USE_LPF_RECEIVE)
 169 /* Packet filter program...
 170    XXX Changes to the filter program may require changes to the constant
 171    offsets used in if_register_send to patch the BPF program! XXX */
 172
 173 struct bpf_insn dhcp_bpf_filter [] = {
 174         /* Make sure this is an IP packet... */
 175         BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
 176         BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
 177
 178         /* Make sure it's a UDP packet... */
 179         BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
 180         BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
 181
 182         /* Make sure this isn't a fragment... */
 183         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
 184         BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
 185
 186         /* Get the IP header length... */
 187         BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
 188
 189         /* Make sure it's to the right port... */
 190         BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
 191         BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1),             /* patch */
 192
 193         /* If we passed all the tests, ask for the whole packet. */
 194         BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
 195
 196         /* Otherwise, drop it. */
 197         BPF_STMT(BPF_RET+BPF_K, 0),
 198 };
 199
 200 #if defined (DEC_FDDI)
 201 struct bpf_insn *bpf_fddi_filter;
 202 #endif
 203
 204 int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
 205 #if defined (HAVE_TR_SUPPORT)
 206 struct bpf_insn dhcp_bpf_tr_filter [] = {
 207         /* accept all token ring packets due to variable length header */
 208         /* if we want to get clever, insert the program here */
 209
 210         /* If we passed all the tests, ask for the whole packet. */
 211         BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
 212
 213         /* Otherwise, drop it. */
 214         BPF_STMT(BPF_RET+BPF_K, 0),
 215 };
 216
 217 int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
 218                               sizeof (struct bpf_insn));
 219 #endif /* HAVE_TR_SUPPORT */
 220 #endif /* USE_LPF_RECEIVE || USE_BPF_RECEIVE */
 221
 222 #if defined (USE_BPF_RECEIVE)
 223 void if_register_receive (info)
 224         struct interface_info *info;
 225 {
 226         int flag = 1;
 227         struct bpf_version v;
 228         u_int32_t addr;
 229         struct bpf_program p;
 230         u_int32_t bits;
 231 #ifdef DEC_FDDI
 232         int link_layer;
 233 #endif /* DEC_FDDI */
 234
 235         /* Open a BPF device and hang it on this interface... */
 236         info -> rfdesc = if_register_bpf (info);
 237
 238         /* Make sure the BPF version is in range... */
 239         if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
 240                 log_fatal ("Can't get BPF version: %m");
 241
 242         if (v.bv_major != BPF_MAJOR_VERSION ||
 243             v.bv_minor < BPF_MINOR_VERSION)
 244                 log_fatal ("BPF version mismatch - recompile DHCP!");
 245
 246         /* Set immediate mode so that reads return as soon as a packet
 247            comes in, rather than waiting for the input buffer to fill with
 248            packets. */
 249         if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
 250                 log_fatal ("Can't set immediate mode on bpf device: %m");
 251
 252 #ifdef NEED_OSF_PFILT_HACKS
 253         /* Allow the copyall flag to be set... */
 254         if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
 255                 log_fatal ("Can't set ALLOWCOPYALL: %m");
 256
 257         /* Clear all the packet filter mode bits first... */
 258         bits = 0;
 259         if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
 260                 log_fatal ("Can't clear pfilt bits: %m");
 261
 262         /* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
 263         bits = ENBATCH | ENCOPYALL | ENBPFHDR;
 264         if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
 265                 log_fatal ("Can't set ENBATCH|ENCOPYALL|ENBPFHDR: %m");
 266 #endif
 267         /* Get the required BPF buffer length from the kernel. */
 268         if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
 269                 log_fatal ("Can't get bpf buffer length: %m");
 270         info -> rbuf = dmalloc (info -> rbuf_max, MDL);
 271         if (!info -> rbuf)
 272                 log_fatal ("Can't allocate %ld bytes for bpf input buffer.",
 273                            (long)(info -> rbuf_max));
 274         info -> rbuf_offset = 0;
 275         info -> rbuf_len = 0;
 276
 277         /* Set up the bpf filter program structure. */
 278         p.bf_len = dhcp_bpf_filter_len;
 279
 280 #ifdef DEC_FDDI
 281         /* See if this is an FDDI interface, flag it for later. */
 282         if (ioctl(info -> rfdesc, BIOCGDLT, &link_layer) >= 0 &&
 283             link_layer == DLT_FDDI) {
 284                 if (!bpf_fddi_filter) {
 285                         bpf_fddi_filter = dmalloc (sizeof bpf_fddi_filter,
 286                                                     MDL);
 287                         if (!bpf_fddi_filter)
 288                                 log_fatal ("No memory for FDDI filter.");
 289                         memcpy (bpf_fddi_filter,
 290                                 dhcp_bpf_filter, sizeof dhcp_bpf_filter);
 291                         /* Patch the BPF program to account for the difference
 292                            in length between ethernet headers (14), FDDI and
 293                            802.2 headers (16 +8=24, +10).
 294                            XXX changes to filter program may require changes to
 295                            XXX the insn number(s) used below! */
 296                         bpf_fddi_filter[0].k += 10;
 297                         bpf_fddi_filter[2].k += 10;
 298                         bpf_fddi_filter[4].k += 10;
 299                         bpf_fddi_filter[6].k += 10;
 300                         bpf_fddi_filter[7].k += 10;
 301                 }
 302                 p.bf_insns = bpf_fddi_filter;
 303         } else
 304 #endif /* DEC_FDDI */
 305         p.bf_insns = dhcp_bpf_filter;
 306
 307         /* Patch the server port into the BPF  program...
 308            XXX changes to filter program may require changes
 309            to the insn number(s) used below! XXX */
 310         dhcp_bpf_filter [8].k = ntohs (local_port);
 311
 312         if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
 313                 log_fatal ("Can't install packet filter program: %m");
 314         if (!quiet_interface_discovery)
 315                 log_info ("Listening on BPF/%s/%s%s%s",
 316                       info -> name,
 317                       print_hw_addr (info -> hw_address.hbuf [0],
 318                                      info -> hw_address.hlen - 1,
 319                                      &info -> hw_address.hbuf [1]),
 320                       (info -> shared_network ? "/" : ""),
 321                       (info -> shared_network ?
 322                        info -> shared_network -> name : ""));
 323 }
 324
 325 void if_deregister_receive (info)
 326         struct interface_info *info;
 327 {
 328         close (info -> rfdesc);
 329         info -> rfdesc = -1;
 330
 331         if (!quiet_interface_discovery)
 332                 log_info ("Disabling input on BPF/%s/%s%s%s",
 333                       info -> name,
 334                       print_hw_addr (info -> hw_address.hbuf [0],
 335                                      info -> hw_address.hlen - 1,
 336                                      &info -> hw_address.hbuf [1]),
 337                       (info -> shared_network ? "/" : ""),
 338                       (info -> shared_network ?
 339                        info -> shared_network -> name : ""));
 340 }
 341 #endif /* USE_BPF_RECEIVE */
 342
 343 #ifdef USE_BPF_SEND
 344 ssize_t send_packet (interface, packet, raw, len, from, to, hto)
 345         struct interface_info *interface;
 346         struct packet *packet;
 347         struct dhcp_packet *raw;
 348         size_t len;
 349         struct in_addr from;
 350         struct sockaddr_in *to;
 351         struct hardware *hto;
 352 {
 353         unsigned hbufp = 0, ibufp = 0;
 354         double hw [4];
 355         double ip [32];
 356         struct iovec iov [3];
 357         int result;
 358         int fudge;
 359
 360         if (!strcmp (interface -> name, "fallback"))
 361                 return send_fallback (interface, packet, raw,
 362                                       len, from, to, hto);
 363
 364         /* Assemble the headers... */
 365         assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
 366         assemble_udp_ip_header (interface,
 367                                 (unsigned char *)ip, &ibufp, from.s_addr,
 368                                 to -> sin_addr.s_addr, to -> sin_port,
 369                                 (unsigned char *)raw, len);
 370
 371         /* Fire it off */
 372         iov [0].iov_base = ((char *)hw);
 373         iov [0].iov_len = hbufp;
 374         iov [1].iov_base = ((char *)ip);
 375         iov [1].iov_len = ibufp;
 376         iov [2].iov_base = (char *)raw;
 377         iov [2].iov_len = len;
 378
 379         result = writev(interface -> wfdesc, iov, 3);
 380         if (result < 0)
 381                 log_error ("send_packet: %m");
 382         return result;
 383 }
 384 #endif /* USE_BPF_SEND */
 385
 386 #ifdef USE_BPF_RECEIVE
 387 ssize_t receive_packet (interface, buf, len, from, hfrom)
 388         struct interface_info *interface;
 389         unsigned char *buf;
 390         size_t len;
 391         struct sockaddr_in *from;
 392         struct hardware *hfrom;
 393 {
 394         int length = 0;
 395         int offset = 0;
 396         struct bpf_hdr hdr;
 397
 398         /* All this complexity is because BPF doesn't guarantee
 399            that only one packet will be returned at a time.   We're
 400            getting what we deserve, though - this is a terrible abuse
 401            of the BPF interface.   Sigh. */
 402
 403         /* Process packets until we get one we can return or until we've
 404            done a read and gotten nothing we can return... */
 405
 406         do {
 407                 /* If the buffer is empty, fill it. */
 408                 if (interface -> rbuf_offset == interface -> rbuf_len) {
 409                         length = read (interface -> rfdesc,
 410                                        interface -> rbuf,
 411                                        (size_t)interface -> rbuf_max);
 412                         if (length <= 0) {
 413 #ifdef __FreeBSD__
 414                                 if (errno == ENXIO) {
 415 #else
 416                                 if (errno == EIO) {
 417 #endif
 418                                         dhcp_interface_remove
 419                                                 ((omapi_object_t *)interface,
 420                                                  (omapi_object_t *)0);
 421                                 }
 422                                 return length;
 423                         }
 424                         interface -> rbuf_offset = 0;
 425                         interface -> rbuf_len = BPF_WORDALIGN (length);
 426                 }
 427
 428                 /* If there isn't room for a whole bpf header, something went
 429                    wrong, but we'll ignore it and hope it goes away... XXX */
 430                 if (interface -> rbuf_len -
 431                     interface -> rbuf_offset < sizeof hdr) {
 432                         interface -> rbuf_offset = interface -> rbuf_len;
 433                         continue;
 434                 }
 435
 436                 /* Copy out a bpf header... */
 437                 memcpy (&hdr, &interface -> rbuf [interface -> rbuf_offset],
 438                         sizeof hdr);
 439
 440                 /* If the bpf header plus data doesn't fit in what's left
 441                    of the buffer, stick head in sand yet again... */
 442                 if (interface -> rbuf_offset +
 443                     hdr.bh_hdrlen + hdr.bh_caplen > interface -> rbuf_len) {
 444                         interface -> rbuf_offset = interface -> rbuf_len;
 445                         continue;
 446                 }
 447
 448                 /* If the captured data wasn't the whole packet, or if
 449                    the packet won't fit in the input buffer, all we
 450                    can do is drop it. */
 451                 if (hdr.bh_caplen != hdr.bh_datalen) {
 452                         interface -> rbuf_offset =
 453                                 BPF_WORDALIGN (interface -> rbuf_offset +
 454                                                hdr.bh_hdrlen + hdr.bh_caplen);
 455                         continue;
 456                 }
 457
 458                 /* Skip over the BPF header... */
 459                 interface -> rbuf_offset += hdr.bh_hdrlen;
 460
 461                 /* Decode the physical header... */
 462                 offset = decode_hw_header (interface,
 463                                            interface -> rbuf,
 464                                            interface -> rbuf_offset,
 465                                            hfrom);
 466
 467                 /* If a physical layer checksum failed (dunno of any
 468                    physical layer that supports this, but WTH), skip this
 469                    packet. */
 470                 if (offset < 0) {
 471                         interface -> rbuf_offset =
 472                                 BPF_WORDALIGN (interface -> rbuf_offset +
 473                                                hdr.bh_caplen);
 474                         continue;
 475                 }
 476                 interface -> rbuf_offset += offset;
 477                 hdr.bh_caplen -= offset;
 478
 479                 /* Decode the IP and UDP headers... */
 480                 offset = decode_udp_ip_header (interface,
 481                                                interface -> rbuf,
 482                                                interface -> rbuf_offset,
 483                                                from,
 484                                                hdr.bh_caplen);
 485
 486                 /* If the IP or UDP checksum was bad, skip the packet... */
 487                 if (offset < 0) {
 488                         interface -> rbuf_offset =
 489                                 BPF_WORDALIGN (interface -> rbuf_offset +
 490                                                hdr.bh_caplen);
 491                         continue;
 492                 }
 493                 interface -> rbuf_offset = interface -> rbuf_offset + offset;
 494                 hdr.bh_caplen -= offset;
 495
 496                 /* If there's not enough room to stash the packet data,
 497                    we have to skip it (this shouldn't happen in real
 498                    life, though). */
 499                 if (hdr.bh_caplen > len) {
 500                         interface -> rbuf_offset =
 501                                 BPF_WORDALIGN (interface -> rbuf_offset +
 502                                                hdr.bh_caplen);
 503                         continue;
 504                 }
 505
 506                 /* Copy out the data in the packet... */
 507                 memcpy (buf, interface -> rbuf + interface -> rbuf_offset,
 508                         hdr.bh_caplen);
 509                 interface -> rbuf_offset =
 510                         BPF_WORDALIGN (interface -> rbuf_offset +
 511                                        hdr.bh_caplen);
 512                 return hdr.bh_caplen;
 513         } while (!length);
 514         return 0;
 515 }
 516
 517 int can_unicast_without_arp (ip)
 518         struct interface_info *ip;
 519 {
 520         return 1;
 521 }
 522
 523 int can_receive_unicast_unconfigured (ip)
 524         struct interface_info *ip;
 525 {
 526         return 1;
 527 }
 528
 529 int supports_multiple_interfaces (ip)
 530         struct interface_info *ip;
 531 {
 532         return 1;
 533 }
 534
 535 void maybe_setup_fallback ()
 536 {
 537         isc_result_t status;
 538         struct interface_info *fbi = (struct interface_info *)0;
 539         if (setup_fallback (&fbi, MDL)) {
 540                 if_register_fallback (fbi);
 541                 status = omapi_register_io_object ((omapi_object_t *)fbi,
 542                                                    if_readsocket, 0,
 543                                                    fallback_discard, 0, 0);
 544                 if (status != ISC_R_SUCCESS)
 545                         log_fatal ("Can't register I/O handle for %s: %s",
 546                                    fbi -> name, isc_result_totext (status));
 547                 interface_dereference (&fbi, MDL);
 548         }
 549 }
 550 #endif