diff options
Diffstat (limited to 'dhcpcd/bpf-filter.h')
| -rw-r--r-- | dhcpcd/bpf-filter.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/dhcpcd/bpf-filter.h b/dhcpcd/bpf-filter.h new file mode 100644 index 00000000..9bd15d8d --- /dev/null +++ b/dhcpcd/bpf-filter.h @@ -0,0 +1,101 @@ +/* + * dhcpcd - DHCP client daemon + * Copyright (c) 2006-2008 Roy Marples <roy@marples.name> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef BPF_ETHCOOK +# define BPF_ETHCOOK 0 +#endif +#ifndef BPF_WHOLEPACKET +# define BPF_WHOLEPACKET ~0U +#endif +static const struct bpf_insn arp_bpf_filter [] = { +#ifndef BPF_SKIPTYPE + /* Make sure this is an ARP packet... */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3), +#endif + /* Make sure this is an ARP REQUEST... */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0), + /* or ARP REPLY... */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), + /* If we passed all the tests, ask for the whole packet. */ + BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET), + /* Otherwise, drop it. */ + BPF_STMT(BPF_RET + BPF_K, 0), +}; +static const size_t arp_bpf_filter_len = + sizeof(arp_bpf_filter) / sizeof(arp_bpf_filter[0]); + + +/* dhcp_bpf_filter taken from bpf.c in dhcp-3.1.0 + * + * Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC") + * Copyright (c) 1996-2003 by Internet Software Consortium + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT + * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + * Internet Systems Consortium, Inc. + * 950 Charter Street + * Redwood City, CA 94063 + * <info@isc.org> + * http://www.isc.org/ + */ + +static const struct bpf_insn dhcp_bpf_filter [] = { +#ifndef BPF_SKIPTYPE + /* Make sure this is an IP packet... */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8), +#endif + /* Make sure it's a UDP packet... */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 23 + BPF_ETHCOOK), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6), + /* Make sure this isn't a fragment... */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK), + BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0), + /* Get the IP header length... */ + BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, 14 + BPF_ETHCOOK), + /* Make sure it's to the right port... */ + BPF_STMT(BPF_LD + BPF_H + BPF_IND, 16 + BPF_ETHCOOK), + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1), + /* If we passed all the tests, ask for the whole packet. */ + BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET), + /* Otherwise, drop it. */ + BPF_STMT(BPF_RET + BPF_K, 0), +}; +static const size_t dhcp_bpf_filter_len = + sizeof(dhcp_bpf_filter) / sizeof(dhcp_bpf_filter[0]); |