8eeb8277e5
dhcpcd is a small DHCP client, supporting most, if not all, features of dhclient. It is much smaller (1/6 of the size on amd64), but still supports many of the more advanced modern RFCs like IPv4LL (RFC 3927), Classless Static Routes (RFC 3442) and Node-specific Client Identifiers (RFC 4361). It was written by Roy Marpled, partly in reply to the discussion of the DHCP client Sommer of Code project.
108 lines
4.1 KiB
C
108 lines
4.1 KiB
C
/*
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* dhcpcd - DHCP client daemon
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* Copyright 2006-2008 Roy Marples <roy@marples.name>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef BPF_ETHCOOK
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# define BPF_ETHCOOK 0
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#endif
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#ifndef BPF_WHOLEPACKET
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# define BPF_WHOLEPACKET ~0U
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#endif
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static const struct bpf_insn const arp_bpf_filter [] = {
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#ifndef BPF_SKIPTYPE
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/* Make sure this is an ARP packet... */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3),
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#endif
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/* Make sure this is an ARP REPLY... */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1),
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/* If we passed all the tests, ask for the whole packet. */
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BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
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/* Otherwise, drop it. */
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BPF_STMT(BPF_RET + BPF_K, 0),
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};
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static const size_t arp_bpf_filter_len =
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sizeof(arp_bpf_filter) / sizeof(arp_bpf_filter[0]);
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/* dhcp_bpf_filter taken from bpf.c in dhcp-3.1.0
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*
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* Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996-2003 by Internet Software Consortium
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Internet Systems Consortium, Inc.
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* 950 Charter Street
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* Redwood City, CA 94063
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* <info@isc.org>
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* http://www.isc.org/
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*/
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static const struct bpf_insn const dhcp_bpf_filter [] = {
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#ifndef BPF_SKIPTYPE
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/* Make sure this is an IP packet... */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
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#endif
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/* Make sure it's a UDP packet... */
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BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 23 + BPF_ETHCOOK),
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
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/* Make sure this isn't a fragment... */
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BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
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BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
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/* Get the IP header length... */
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BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, 14 + BPF_ETHCOOK),
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/* Make sure it's to the right port... */
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BPF_STMT(BPF_LD + BPF_H + BPF_IND, 16 + BPF_ETHCOOK),
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BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1),
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/* If we passed all the tests, ask for the whole packet. */
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BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
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/* Otherwise, drop it. */
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BPF_STMT(BPF_RET + BPF_K, 0),
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};
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static const size_t dhcp_bpf_filter_len =
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sizeof(dhcp_bpf_filter) / sizeof(dhcp_bpf_filter[0]);
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