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

   1 /* $NetBSD: bpf-filter.h,v 1.9 2014/11/07 20:51:02 roy Exp $ */
   2
   3 /*
   4  * dhcpcd - DHCP client daemon
   5  * Copyright (c) 2006-2008 Roy Marples <roy@marples.name>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #ifndef BPF_ETHCOOK
  30 # define BPF_ETHCOOK 0
  31 #endif
  32 #ifndef BPF_WHOLEPACKET
  33 # define BPF_WHOLEPACKET ~0U
  34 #endif
  35 static const struct bpf_insn arp_bpf_filter [] = {
  36 #ifndef BPF_SKIPTYPE
  37         /* Make sure this is an ARP packet... */
  38         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
  39         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3),
  40 #endif
  41         /* Make sure this is an ARP REQUEST... */
  42         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  43         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0),
  44         /* or ARP REPLY... */
  45         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  46         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1),
  47         /* If we passed all the tests, ask for the whole packet. */
  48         BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
  49         /* Otherwise, drop it. */
  50         BPF_STMT(BPF_RET + BPF_K, 0),
  51 };
  52 #define arp_bpf_filter_len sizeof(arp_bpf_filter) / sizeof(arp_bpf_filter[0])
  53
  54
  55 /* dhcp_bpf_filter taken from bpf.c in dhcp-3.1.0
  56  *
  57  * Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC")
  58  * Copyright (c) 1996-2003 by Internet Software Consortium
  59  *
  60  * Permission to use, copy, modify, and distribute this software for any
  61  * purpose with or without fee is hereby granted, provided that the above
  62  * copyright notice and this permission notice appear in all copies.
  63  *
  64  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  65  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  66  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  67  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  68  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  69  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  70  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  71  *
  72  *   Internet Systems Consortium, Inc.
  73  *   950 Charter Street
  74  *   Redwood City, CA 94063
  75  *   <info@isc.org>
  76  *   http://www.isc.org/
  77  */
  78
  79 static const struct bpf_insn dhcp_bpf_filter [] = {
  80 #ifndef BPF_SKIPTYPE
  81         /* Make sure this is an IP packet... */
  82         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
  83         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
  84 #endif
  85         /* Make sure it's a UDP packet... */
  86         BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 23 + BPF_ETHCOOK),
  87         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
  88         /* Make sure this isn't a fragment... */
  89         BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
  90         BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
  91         /* Get the IP header length... */
  92         BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, 14 + BPF_ETHCOOK),
  93         /* Make sure it's to the right port... */
  94         BPF_STMT(BPF_LD + BPF_H + BPF_IND, 16 + BPF_ETHCOOK),
  95         BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1),
  96         /* If we passed all the tests, ask for the whole packet. */
  97         BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
  98         /* Otherwise, drop it. */
  99         BPF_STMT(BPF_RET + BPF_K, 0),
 100 };
 101 #define dhcp_bpf_filter_len sizeof(dhcp_bpf_filter) / sizeof(dhcp_bpf_filter[0])