380 lines
11 KiB
C
380 lines
11 KiB
C
/* nit.c
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Network Interface Tap (NIT) network interface code, by Ted Lemon
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with one crucial tidbit of help from Stu Grossmen. */
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/*
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* Copyright (c) 1996, 1998, 1999 The Internet Software Consortium.
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* 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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#ifndef lint
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static char copyright[] =
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"$Id: nit.c,v 1.15.2.4 1999/03/29 22:07:14 mellon Exp $ Copyright (c) 1996 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_NIT_SEND) || defined (USE_NIT_RECEIVE)
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#include <sys/ioctl.h>
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#include <sys/uio.h>
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#include <sys/time.h>
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#include <net/nit.h>
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#include <net/nit_if.h>
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#include <net/nit_pf.h>
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#include <net/nit_buf.h>
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#include <sys/stropts.h>
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#include <net/packetfilt.h>
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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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/* 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_NIT_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_NIT_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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int if_register_nit (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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struct ifreq ifr;
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struct strioctl sio;
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/* Open a NIT device */
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sock = open ("/dev/nit", O_RDWR);
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if (sock < 0)
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error ("Can't open NIT device for %s: %m", info -> name);
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/* Set the NIT device to point at this interface. */
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sio.ic_cmd = NIOCBIND;
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sio.ic_len = sizeof *(info -> ifp);
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sio.ic_dp = (char *)(info -> ifp);
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sio.ic_timout = INFTIM;
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if (ioctl (sock, I_STR, &sio) < 0)
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error ("Can't attach interface %s to nit device: %m",
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info -> name);
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/* Get the low-level address... */
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sio.ic_cmd = SIOCGIFADDR;
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sio.ic_len = sizeof ifr;
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sio.ic_dp = (char *)𝔦
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sio.ic_timout = INFTIM;
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if (ioctl (sock, I_STR, &sio) < 0)
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error ("Can't get physical layer address for %s: %m",
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info -> name);
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/* XXX code below assumes ethernet interface! */
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info -> hw_address.hlen = 6;
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info -> hw_address.htype = ARPHRD_ETHER;
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memcpy (info -> hw_address.haddr, ifr.ifr_ifru.ifru_addr.sa_data, 6);
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if (ioctl (sock, I_PUSH, "pf") < 0)
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error ("Can't push packet filter onto NIT for %s: %m",
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info -> name);
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return sock;
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}
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#endif /* USE_NIT_SEND || USE_NIT_RECEIVE */
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#ifdef USE_NIT_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 nit API for sending and receiving,
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we don't need to register this interface twice. */
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#ifndef USE_NIT_RECEIVE
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struct packetfilt pf;
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struct strioctl sio;
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info -> wfdesc = if_register_nit (info);
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pf.Pf_Priority = 0;
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pf.Pf_FilterLen = 1;
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pf.Pf_Filter [0] = ENF_PUSHZERO;
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/* Set up an NIT filter that rejects everything... */
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sio.ic_cmd = NIOCSETF;
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sio.ic_len = sizeof pf;
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sio.ic_dp = (char *)&pf;
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sio.ic_timout = INFTIM;
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if (ioctl (info -> wfdesc, I_STR, &sio) < 0)
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error ("Can't set NIT filter: %m");
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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 NIT/%s%s%s",
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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_NIT_SEND */
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#ifdef USE_NIT_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 NIT program! XXX */
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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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u_int32_t x;
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struct packetfilt pf;
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struct strioctl sio;
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u_int16_t addr [2];
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struct timeval t;
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/* Open a NIT device and hang it on this interface... */
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info -> rfdesc = if_register_nit (info);
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/* Set the snap length to 0, which means always take the whole
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packet. */
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x = 0;
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if (ioctl (info -> rfdesc, NIOCSSNAP, &x) < 0)
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error ("Can't set NIT snap length on %s: %m", info -> name);
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/* Set the stream to byte stream mode */
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if (ioctl (info -> rfdesc, I_SRDOPT, RMSGN) != 0)
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note ("I_SRDOPT failed on %s: %m", info -> name);
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#if 0
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/* Push on the chunker... */
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if (ioctl (info -> rfdesc, I_PUSH, "nbuf") < 0)
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error ("Can't push chunker onto NIT STREAM: %m");
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/* Set the timeout to zero. */
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t.tv_sec = 0;
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t.tv_usec = 0;
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if (ioctl (info -> rfdesc, NIOCSTIME, &t) < 0)
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error ("Can't set chunk timeout: %m");
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#endif
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/* Ask for no header... */
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x = 0;
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if (ioctl (info -> rfdesc, NIOCSFLAGS, &x) < 0)
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error ("Can't set NIT flags on %s: %m", info -> name);
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/* Set up the NIT filter program. */
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/* XXX Unlike the BPF filter program, this one won't work if the
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XXX IP packet is fragmented or if there are options on the IP
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XXX header. */
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pf.Pf_Priority = 0;
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pf.Pf_FilterLen = 0;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 6;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (ETHERTYPE_IP);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_AND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = htons (0xFF);
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 18;
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pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
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pf.Pf_Filter [pf.Pf_FilterLen++] = local_port;
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/* Install the filter... */
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sio.ic_cmd = NIOCSETF;
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sio.ic_len = sizeof pf;
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sio.ic_dp = (char *)&pf;
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sio.ic_timout = INFTIM;
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if (ioctl (info -> rfdesc, I_STR, &sio) < 0)
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error ("Can't set NIT filter on %s: %m", info -> name);
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if (!quiet_interface_discovery)
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note ("Listening on NIT/%s%s%s",
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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_NIT_RECEIVE */
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#ifdef USE_NIT_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;
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unsigned char buf [1536 + sizeof (struct sockaddr)];
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struct sockaddr *junk;
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struct strbuf ctl, data;
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int hw_end;
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struct sockaddr_in foo;
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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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/* Start with the sockaddr struct... */
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junk = (struct sockaddr *)&buf [0];
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bufp = ((unsigned char *)&junk -> sa_data [0]) - &buf [0];
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/* Assemble the headers... */
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assemble_hw_header (interface, buf, &bufp, hto);
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hw_end = bufp;
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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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raw, len);
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/* Copy the data into the buffer (yuk). */
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memcpy (buf + bufp, raw, len);
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/* Set up the sockaddr structure... */
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#if USE_SIN_LEN
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junk -> sa_len = hw_end - 2; /* XXX */
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#endif
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junk -> sa_family = AF_UNSPEC;
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#if 0 /* Already done. */
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memcpy (junk.sa_data, buf, hw_len);
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#endif
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/* Set up the msg_buf structure... */
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ctl.buf = (char *)&buf [0];
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ctl.maxlen = ctl.len = hw_end;
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data.buf = (char *)&buf [hw_end];
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data.maxlen = data.len = bufp + len - hw_end;
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result = putmsg (interface -> wfdesc, &ctl, &data, 0);
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if (result < 0)
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warn ("send_packet: %m");
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return result;
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}
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#endif /* USE_NIT_SEND */
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#ifdef USE_NIT_RECEIVE
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ssize_t receive_packet (interface, buf, len, from, hfrom)
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struct interface_info *interface;
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unsigned char *buf;
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size_t len;
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struct sockaddr_in *from;
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struct hardware *hfrom;
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{
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int nread;
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int length = 0;
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int offset = 0;
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unsigned char ibuf [1536];
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int bufix = 0;
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length = read (interface -> rfdesc, ibuf, sizeof ibuf);
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if (length <= 0)
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return length;
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/* Decode the physical header... */
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offset = decode_hw_header (interface, ibuf, bufix, hfrom);
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/* If a physical layer checksum failed (dunno of any
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physical layer that supports this, but WTH), skip this
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packet. */
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if (offset < 0) {
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return 0;
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}
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bufix += offset;
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length -= offset;
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/* Decode the IP and UDP headers... */
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offset = decode_udp_ip_header (interface, ibuf, bufix,
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from, (unsigned char *)0, length);
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/* If the IP or UDP checksum was bad, skip the packet... */
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if (offset < 0)
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return 0;
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bufix += offset;
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length -= offset;
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/* Copy out the data in the packet... */
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memcpy (buf, &ibuf [bufix], length);
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return length;
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}
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int can_unicast_without_arp ()
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{
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return 1;
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}
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int can_receive_unicast_unconfigured (ip)
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struct interface_info *ip;
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{
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return 1;
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}
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void maybe_setup_fallback ()
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{
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struct interface_info *fbi;
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fbi = setup_fallback ();
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if (fbi) {
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if_register_fallback (fbi);
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add_protocol ("fallback", fallback_interface -> wfdesc,
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fallback_discard, fallback_interface);
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}
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}
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#endif
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