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- Committer: Bazaar Package Importer
- Author(s): Martin Schulze
- Date: 2004-10-30 21:07:22 UTC
- Revision ID: james.westby@ubuntu.com-20041030210722-p0u4682vtncfxnnn
Tags: upstream-2.0pl5
Import upstream version 2.0pl5
- files added:
- client
- client/scripts
- common
- doc
- includes
- includes/arpa
- includes/cf
- includes/netinet
- relay
- server
added
removed
common/bpf.c
1
/* bpf.c
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BPF socket interface code, originally contributed by Archie Cobbs. */
4
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/*
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* Copyright (c) 1995, 1996, 1998, 1999
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* The Internet Software Consortium. All rights reserved.
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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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*
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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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* 3. Neither the name of The Internet Software Consortium nor the names
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* of its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
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* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* 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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* This software has been written for the Internet Software Consortium
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* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
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* Enterprises. To learn more about the Internet Software Consortium,
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* see ``http://www.vix.com/isc''. To learn more about Vixie
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* Enterprises, see ``http://www.vix.com''.
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*/
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#ifndef lint
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static char copyright[] =
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"$Id: bpf.c,v 1.19.2.10 1999/05/27 17:44:51 mellon Exp $ Copyright (c) 1995, 1996, 1998, 1999 The Internet Software Consortium. All rights reserved.\n";
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#endif /* not lint */
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#include "dhcpd.h"
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#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE) \
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|| defined (USE_LPF_RECEIVE)
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# if defined (USE_LPF_RECEIVE)
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# include <asm/types.h>
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# include <linux/filter.h>
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# define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
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# else
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# include <sys/ioctl.h>
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# include <sys/uio.h>
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# include <net/bpf.h>
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# if defined (NEED_OSF_PFILT_HACKS)
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# include <net/pfilt.h>
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# endif
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# endif
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#include <netinet/in_systm.h>
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#include "includes/netinet/ip.h"
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#include "includes/netinet/udp.h"
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#include "includes/netinet/if_ether.h"
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#endif
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/* Reinitializes the specified interface after an address change. This
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is not required for packet-filter APIs. */
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#ifdef USE_BPF_SEND
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void if_reinitialize_send (info)
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struct interface_info *info;
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{
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}
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#endif
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#ifdef USE_BPF_RECEIVE
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void if_reinitialize_receive (info)
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struct interface_info *info;
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{
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}
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#endif
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/* Called by get_interface_list for each interface that's discovered.
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Opens a packet filter for each interface and adds it to the select
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mask. */
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#if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)
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int if_register_bpf (info)
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struct interface_info *info;
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{
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int sock;
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char filename[50];
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int b;
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/* Open a BPF device */
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for (b = 0; 1; b++) {
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#ifndef NO_SNPRINTF
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snprintf(filename, sizeof(filename), BPF_FORMAT, b);
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#else
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sprintf(filename, BPF_FORMAT, b);
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#endif
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sock = open (filename, O_RDWR, 0);
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if (sock < 0) {
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if (errno == EBUSY) {
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continue;
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} else {
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if (!b)
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error ("No bpf devices.%s%s%s",
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" Please read the README",
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" section for your operating",
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" system.");
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error ("Can't find free bpf: %m");
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}
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} else {
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break;
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}
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}
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/* Set the BPF device to point at this interface. */
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if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
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error ("Can't attach interface %s to bpf device %s: %m",
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info -> name, filename);
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return sock;
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}
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#endif /* USE_BPF_SEND || USE_BPF_RECEIVE */
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#ifdef USE_BPF_SEND
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void if_register_send (info)
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struct interface_info *info;
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{
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/* If we're using the bpf API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_BPF_RECEIVE
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info -> wfdesc = if_register_bpf (info, interface);
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#else
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info -> wfdesc = info -> rfdesc;
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#endif
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if (!quiet_interface_discovery)
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note ("Sending on BPF/%s/%s%s%s",
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info -> name,
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print_hw_addr (info -> hw_address.htype,
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info -> hw_address.hlen,
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info -> hw_address.haddr),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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}
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#endif /* USE_BPF_SEND */
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#if defined (USE_BPF_RECEIVE) || defined (USE_LPF_RECEIVE)
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/* Packet filter program...
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XXX Changes to the filter program may require changes to the constant
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offsets used in if_register_send to patch the BPF program! XXX */
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struct bpf_insn dhcp_bpf_filter [] = {
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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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/* Make sure it's a UDP packet... */
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BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
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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),
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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),
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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),
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BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1), /* patch */
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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, (u_int)-1),
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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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int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
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struct bpf_insn dhcp_bpf_tr_filter [] = {
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/* accept all token ring packets due to variable length header */
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/* if we want to get clever, insert the program here */
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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, (u_int)-1),
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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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int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
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sizeof (struct bpf_insn));
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#endif
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#if defined (USE_BPF_RECEIVE)
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void if_register_receive (info)
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struct interface_info *info;
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{
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int flag = 1;
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struct bpf_version v;
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u_int32_t addr;
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struct bpf_program p;
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u_int32_t bits;
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/* Open a BPF device and hang it on this interface... */
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info -> rfdesc = if_register_bpf (info);
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/* Make sure the BPF version is in range... */
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if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
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error ("Can't get BPF version: %m");
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if (v.bv_major != BPF_MAJOR_VERSION ||
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v.bv_minor < BPF_MINOR_VERSION)
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error ("Kernel BPF version out of range - recompile dhcpd!");
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/* Set immediate mode so that reads return as soon as a packet
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comes in, rather than waiting for the input buffer to fill with
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packets. */
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if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
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error ("Can't set immediate mode on bpf device: %m");
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#ifdef NEED_OSF_PFILT_HACKS
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/* Allow the copyall flag to be set... */
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if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
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error ("Can't set ALLOWCOPYALL: %m");
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/* Clear all the packet filter mode bits first... */
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bits = 0;
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if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
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error ("Can't clear pfilt bits: %m");
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/* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
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bits = ENBATCH | ENCOPYALL | ENBPFHDR;
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if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
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error ("Can't set ENBATCH|ENCOPYALL|ENBPFHDR: %m");
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#endif
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/* Get the required BPF buffer length from the kernel. */
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if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
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error ("Can't get bpf buffer length: %m");
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info -> rbuf = malloc (info -> rbuf_max);
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if (!info -> rbuf)
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error ("Can't allocate %d bytes for bpf input buffer.");
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info -> rbuf_offset = 0;
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info -> rbuf_len = 0;
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/* Set up the bpf filter program structure. */
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p.bf_len = dhcp_bpf_filter_len;
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p.bf_insns = dhcp_bpf_filter;
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/* Patch the server port into the BPF program...
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XXX changes to filter program may require changes
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to the insn number(s) used below! XXX */
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dhcp_bpf_filter [8].k = ntohs (local_port);
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if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
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error ("Can't install packet filter program: %m");
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if (!quiet_interface_discovery)
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note ("Listening on BPF/%s/%s%s%s",
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info -> name,
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print_hw_addr (info -> hw_address.htype,
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info -> hw_address.hlen,
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info -> hw_address.haddr),
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(info -> shared_network ? "/" : ""),
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(info -> shared_network ?
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info -> shared_network -> name : ""));
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}
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#endif /* USE_BPF_RECEIVE */
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#ifdef USE_BPF_SEND
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ssize_t send_packet (interface, packet, raw, len, from, to, hto)
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struct interface_info *interface;
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struct packet *packet;
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struct dhcp_packet *raw;
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size_t len;
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struct in_addr from;
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struct sockaddr_in *to;
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struct hardware *hto;
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{
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int bufp = 0;
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unsigned char buf [256];
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struct iovec iov [2];
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int result;
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if (!strcmp (interface -> name, "fallback"))
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return send_fallback (interface, packet, raw,
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len, from, to, hto);
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/* Assemble the headers... */
299
assemble_hw_header (interface, buf, &bufp, hto);
300
assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
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to -> sin_addr.s_addr, to -> sin_port,
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(unsigned char *)raw, len);
303
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/* Fire it off */
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iov [0].iov_base = (char *)buf;
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iov [0].iov_len = bufp;
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iov [1].iov_base = (char *)raw;
308
iov [1].iov_len = len;
309
310
result = writev(interface -> wfdesc, iov, 2);
311
if (result < 0)
312
warn ("send_packet: %m");
313
return result;
314
}
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#endif /* USE_BPF_SEND */
316
317
#ifdef USE_BPF_RECEIVE
318
ssize_t receive_packet (interface, buf, len, from, hfrom)
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struct interface_info *interface;
320
unsigned char *buf;
321
size_t len;
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struct sockaddr_in *from;
323
struct hardware *hfrom;
324
{
325
int length = 0;
326
int offset = 0;
327
struct bpf_hdr hdr;
328
329
/* All this complexity is because BPF doesn't guarantee
330
that only one packet will be returned at a time. We're
331
getting what we deserve, though - this is a terrible abuse
332
of the BPF interface. Sigh. */
333
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/* Process packets until we get one we can return or until we've
335
done a read and gotten nothing we can return... */
336
337
do {
338
/* If the buffer is empty, fill it. */
339
if (interface -> rbuf_offset == interface -> rbuf_len) {
340
length = read (interface -> rfdesc,
341
interface -> rbuf,
342
interface -> rbuf_max);
343
if (length <= 0)
344
return length;
345
interface -> rbuf_offset = 0;
346
interface -> rbuf_len = length;
347
}
348
349
/* If there isn't room for a whole bpf header, something went
350
wrong, but we'll ignore it and hope it goes away... XXX */
351
if (interface -> rbuf_len -
352
interface -> rbuf_offset < sizeof hdr) {
353
interface -> rbuf_offset = interface -> rbuf_len;
354
continue;
355
}
356
357
/* Copy out a bpf header... */
358
memcpy (&hdr, &interface -> rbuf [interface -> rbuf_offset],
359
sizeof hdr);
360
361
/* If the bpf header plus data doesn't fit in what's left
362
of the buffer, stick head in sand yet again... */
363
if (interface -> rbuf_offset +
364
hdr.bh_hdrlen + hdr.bh_caplen > interface -> rbuf_len) {
365
interface -> rbuf_offset = interface -> rbuf_len;
366
continue;
367
}
368
369
/* If the captured data wasn't the whole packet, or if
370
the packet won't fit in the input buffer, all we
371
can do is drop it. */
372
if (hdr.bh_caplen != hdr.bh_datalen) {
373
interface -> rbuf_offset +=
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hdr.bh_hdrlen = hdr.bh_caplen;
375
continue;
376
}
377
378
/* Skip over the BPF header... */
379
interface -> rbuf_offset += hdr.bh_hdrlen;
380
381
/* Decode the physical header... */
382
offset = decode_hw_header (interface,
383
interface -> rbuf,
384
interface -> rbuf_offset,
385
hfrom);
386
387
/* If a physical layer checksum failed (dunno of any
388
physical layer that supports this, but WTH), skip this
389
packet. */
390
if (offset < 0) {
391
interface -> rbuf_offset += hdr.bh_caplen;
392
continue;
393
}
394
interface -> rbuf_offset += offset;
395
hdr.bh_caplen -= offset;
396
397
/* Decode the IP and UDP headers... */
398
offset = decode_udp_ip_header (interface,
399
interface -> rbuf,
400
interface -> rbuf_offset,
401
from,
402
(unsigned char *)0,
403
hdr.bh_caplen);
404
405
/* If the IP or UDP checksum was bad, skip the packet... */
406
if (offset < 0) {
407
interface -> rbuf_offset += hdr.bh_caplen;
408
continue;
409
}
410
interface -> rbuf_offset += offset;
411
hdr.bh_caplen -= offset;
412
413
/* If there's not enough room to stash the packet data,
414
we have to skip it (this shouldn't happen in real
415
life, though). */
416
if (hdr.bh_caplen > len) {
417
interface -> rbuf_offset += hdr.bh_caplen;
418
continue;
419
}
420
421
/* Copy out the data in the packet... */
422
memcpy (buf, interface -> rbuf + interface -> rbuf_offset,
423
hdr.bh_caplen);
424
interface -> rbuf_offset += hdr.bh_caplen;
425
return hdr.bh_caplen;
426
} while (!length);
427
return 0;
428
}
429
430
int can_unicast_without_arp ()
431
{
432
return 1;
433
}
434
435
int can_receive_unicast_unconfigured (ip)
436
struct interface_info *ip;
437
{
438
return 1;
439
}
440
441
void maybe_setup_fallback ()
442
{
443
struct interface_info *fbi;
444
fbi = setup_fallback ();
445
if (fbi) {
446
if_register_fallback (fbi);
447
add_protocol ("fallback", fallback_interface -> wfdesc,
448
fallback_discard, fallback_interface);
449
}
450
}
451
#endif
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