425 lines
10 KiB
C
425 lines
10 KiB
C
/* $NetBSD: bpf.c,v 1.8 1997/07/28 05:39:17 thorpej Exp $ */
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/*
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* Copyright (c) 1988, 1992 The University of Utah and the Center
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* for Software Science (CSS).
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Center for Software Science of the University of Utah Computer
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* Science Department. CSS requests users of this software to return
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* to css-dist@cs.utah.edu any improvements that they make and grant
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* CSS redistribution rights.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* from: @(#)bpf.c 8.1 (Berkeley) 6/4/93
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*
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* From: Utah Hdr: bpf.c 3.1 92/07/06
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* Author: Jeff Forys, University of Utah CSS
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: bpf.c,v 1.8 1997/07/28 05:39:17 thorpej Exp $");
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#endif
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/bpf.h>
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#include "defs.h"
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#include "pathnames.h"
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static int BpfFd = -1;
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static unsigned BpfLen = 0;
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static u_int8_t *BpfPkt = NULL;
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/*
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** BpfOpen -- Open and initialize a BPF device.
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**
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** Parameters:
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** None.
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**
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** Returns:
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** File descriptor of opened BPF device (for select() etc).
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**
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** Side Effects:
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** If an error is encountered, the program terminates here.
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*/
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int
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BpfOpen()
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{
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struct ifreq ifr;
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char bpfdev[32];
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int n = 0;
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/*
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* Open the first available BPF device.
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*/
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do {
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(void) sprintf(bpfdev, _PATH_BPF, n++);
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BpfFd = open(bpfdev, O_RDWR);
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} while (BpfFd < 0 && (errno == EBUSY || errno == EPERM));
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if (BpfFd < 0) {
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syslog(LOG_ERR, "bpf: no available devices: %m");
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Exit(0);
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}
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/*
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* Set interface name for bpf device, get data link layer
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* type and make sure it's type Ethernet.
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*/
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(void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name));
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if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) {
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syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName);
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Exit(0);
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}
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/*
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* Make sure we are dealing with an Ethernet device.
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*/
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if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) {
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syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m");
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Exit(0);
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}
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if (n != DLT_EN10MB) {
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syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported",
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IntfName, n);
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Exit(0);
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}
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/*
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* On read(), return packets immediately (do not buffer them).
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*/
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n = 1;
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if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) {
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syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m");
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Exit(0);
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}
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/*
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* Try to enable the chip/driver's multicast address filter to
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* grab our RMP address. If this fails, try promiscuous mode.
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* If this fails, there's no way we are going to get any RMP
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* packets so just exit here.
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*/
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#ifdef MSG_EOR
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ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
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#endif
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ifr.ifr_addr.sa_family = AF_UNSPEC;
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bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN);
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if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) {
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syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m");
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Exit(0);
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}
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/*
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* Ask BPF how much buffer space it requires and allocate one.
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*/
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if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) {
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syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m");
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Exit(0);
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}
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if (BpfPkt == NULL)
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BpfPkt = (u_int8_t *)malloc(BpfLen);
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if (BpfPkt == NULL) {
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syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)",
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BpfLen);
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Exit(0);
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}
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/*
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* Write a little program to snarf RMP Boot packets and stuff
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* it down BPF's throat (i.e. set up the packet filter).
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*/
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{
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#define RMP ((struct rmp_packet *)0)
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static struct bpf_insn bpf_insn[] = {
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{ BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap },
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{ BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP },
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{ BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl },
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{ BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP },
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{ BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap },
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{ BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP },
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{ BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET },
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{ BPF_RET|BPF_K, 0, 0, 0x0 }
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};
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#undef RMP
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static struct bpf_program bpf_pgm = {
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sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn
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};
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if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) {
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syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m");
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Exit(0);
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}
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}
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return(BpfFd);
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}
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/*
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** BPF GetIntfName -- Return the name of a network interface attached to
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** the system, or 0 if none can be found. The interface
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** must be configured up; the lowest unit number is
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** preferred; loopback is ignored.
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**
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** Parameters:
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** errmsg - if no network interface found, *errmsg explains why.
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**
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** Returns:
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** A (static) pointer to interface name, or NULL on error.
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**
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** Side Effects:
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** None.
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*/
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char *
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BpfGetIntfName(errmsg)
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char **errmsg;
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{
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struct ifreq ibuf[8], *ifrp, *ifend, *mp;
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struct ifconf ifc;
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int fd;
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int minunit, n;
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char *cp;
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static char device[sizeof(ifrp->ifr_name)];
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static char errbuf[128] = "No Error!";
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if (errmsg != NULL)
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*errmsg = errbuf;
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if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
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(void) strcpy(errbuf, "bpf: socket: %m");
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return(NULL);
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}
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ifc.ifc_len = sizeof ibuf;
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ifc.ifc_buf = (caddr_t)ibuf;
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#ifdef OSIOCGIFCONF
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if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 ||
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ifc.ifc_len < sizeof(struct ifreq)) {
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(void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m");
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return(NULL);
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}
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#else
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if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
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ifc.ifc_len < sizeof(struct ifreq)) {
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(void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m");
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return(NULL);
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}
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#endif
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ifrp = ibuf;
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ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
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mp = 0;
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minunit = 666;
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for (; ifrp < ifend; ++ifrp) {
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if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) {
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(void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m");
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return(NULL);
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}
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/*
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* If interface is down or this is the loopback interface,
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* ignore it.
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*/
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if ((ifrp->ifr_flags & IFF_UP) == 0 ||
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#ifdef IFF_LOOPBACK
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(ifrp->ifr_flags & IFF_LOOPBACK))
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#else
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(strcmp(ifrp->ifr_name, "lo0") == 0))
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#endif
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continue;
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for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
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;
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n = atoi(cp);
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if (n < minunit) {
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minunit = n;
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mp = ifrp;
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}
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}
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(void) close(fd);
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if (mp == 0) {
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(void) strcpy(errbuf, "bpf: no interfaces found");
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return(NULL);
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}
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(void) strcpy(device, mp->ifr_name);
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return(device);
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}
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/*
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** BpfRead -- Read packets from a BPF device and fill in `rconn'.
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**
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** Parameters:
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** rconn - filled in with next packet.
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** doread - is True if we can issue a read() syscall.
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**
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** Returns:
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** True if `rconn' contains a new packet, False otherwise.
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**
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** Side Effects:
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** None.
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*/
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int
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BpfRead(rconn, doread)
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RMPCONN *rconn;
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int doread;
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{
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register int datlen, caplen, hdrlen;
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static u_int8_t *bp = NULL, *ep = NULL;
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int cc;
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/*
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* The read() may block, or it may return one or more packets.
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* We let the caller decide whether or not we can issue a read().
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*/
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if (doread) {
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if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) {
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syslog(LOG_ERR, "bpf: read: %m");
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return(0);
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} else {
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bp = BpfPkt;
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ep = BpfPkt + cc;
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}
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}
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#define bhp ((struct bpf_hdr *)bp)
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/*
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* If there is a new packet in the buffer, stuff it into `rconn'
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* and return a success indication.
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*/
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if (bp < ep) {
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datlen = bhp->bh_datalen;
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caplen = bhp->bh_caplen;
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hdrlen = bhp->bh_hdrlen;
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if (caplen != datlen)
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syslog(LOG_ERR,
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"bpf: short packet dropped (%d of %d bytes)",
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caplen, datlen);
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else if (caplen > sizeof(struct rmp_packet))
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syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)",
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caplen);
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else {
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rconn->rmplen = caplen;
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bcopy((char *)&bhp->bh_tstamp, (char *)&rconn->tstamp,
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sizeof(struct timeval));
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bcopy((char *)bp + hdrlen, (char *)&rconn->rmp, caplen);
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}
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bp += BPF_WORDALIGN(caplen + hdrlen);
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return(1);
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}
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#undef bhp
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return(0);
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}
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/*
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** BpfWrite -- Write packet to BPF device.
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**
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** Parameters:
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** rconn - packet to send.
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**
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** Returns:
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** True if write succeeded, False otherwise.
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**
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** Side Effects:
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** None.
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*/
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int
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BpfWrite(rconn)
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RMPCONN *rconn;
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{
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if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) {
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syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn));
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return(0);
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}
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return(1);
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}
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/*
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** BpfClose -- Close a BPF device.
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**
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** Parameters:
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** None.
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**
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** Returns:
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** Nothing.
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**
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** Side Effects:
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** None.
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*/
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void
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BpfClose()
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{
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struct ifreq ifr;
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if (BpfPkt != NULL) {
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free((char *)BpfPkt);
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BpfPkt = NULL;
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}
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if (BpfFd == -1)
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return;
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#ifdef MSG_EOR
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ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
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#endif
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ifr.ifr_addr.sa_family = AF_UNSPEC;
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bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN);
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if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0)
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(void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0);
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(void) close(BpfFd);
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BpfFd = -1;
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}
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