external/bsd/dhcpcd/dist/bpf-filter.h

   1 /*
   2  * dhcpcd - DHCP client daemon
   3  * Copyright (c) 2006-2008 Roy Marples <roy@marples.name>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #ifndef BPF_ETHCOOK
  28 # define BPF_ETHCOOK 0
  29 #endif
  30 #ifndef BPF_WHOLEPACKET
  31 # define BPF_WHOLEPACKET ~0U
  32 #endif
  33 static const struct bpf_insn const arp_bpf_filter [] = {
  34 #ifndef BPF_SKIPTYPE
  35         /* Make sure this is an ARP packet... */
  36         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
  37         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3),
  38 #endif
  39         /* Make sure this is an ARP REQUEST... */
  40         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  41         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0),
  42         /* or ARP REPLY... */
  43         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  44         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1),
  45         /* If we passed all the tests, ask for the whole packet. */
  46         BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
  47         /* Otherwise, drop it. */
  48         BPF_STMT(BPF_RET + BPF_K, 0),
  49 };
  50 static const size_t arp_bpf_filter_len =
  51     sizeof(arp_bpf_filter) / sizeof(arp_bpf_filter[0]);
  52
  53
  54 /* dhcp_bpf_filter taken from bpf.c in dhcp-3.1.0
  55  *
  56  * Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC")
  57  * Copyright (c) 1996-2003 by Internet Software Consortium
  58  *
  59  * Permission to use, copy, modify, and distribute this software for any
  60  * purpose with or without fee is hereby granted, provided that the above
  61  * copyright notice and this permission notice appear in all copies.
  62  *
  63  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  64  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  65  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  66  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  67  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  68  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  69  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  70  *
  71  *   Internet Systems Consortium, Inc.
  72  *   950 Charter Street
  73  *   Redwood City, CA 94063
  74  *   <info@isc.org>
  75  *   http://www.isc.org/
  76  */
  77
  78 static const struct bpf_insn const dhcp_bpf_filter [] = {
  79 #ifndef BPF_SKIPTYPE
  80         /* Make sure this is an IP packet... */
  81         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
  82         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
  83 #endif
  84         /* Make sure it's a UDP packet... */
  85         BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 23 + BPF_ETHCOOK),
  86         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
  87         /* Make sure this isn't a fragment... */
  88         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  89         BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
  90         /* Get the IP header length... */
  91         BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, 14 + BPF_ETHCOOK),
  92         /* Make sure it's to the right port... */
  93         BPF_STMT(BPF_LD + BPF_H + BPF_IND, 16 + BPF_ETHCOOK),
  94         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1),
  95         /* If we passed all the tests, ask for the whole packet. */
  96         BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
  97         /* Otherwise, drop it. */
  98         BPF_STMT(BPF_RET + BPF_K, 0),
  99 };
 100 static const size_t dhcp_bpf_filter_len =
 101     sizeof(dhcp_bpf_filter) / sizeof(dhcp_bpf_filter[0]);