GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.sbin/rbootd/bpf.c Lines: 0 92 0.0 %
Date: 2017-11-13 Branches: 0 56 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: bpf.c,v 1.26 2017/04/19 05:36:13 natano Exp $	*/
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/*	$NetBSD: bpf.c,v 1.5.2.1 1995/11/14 08:45:42 thorpej Exp $	*/
3
4
/*
5
 * 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. 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/ioctl.h>
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#include <sys/socket.h>
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49
#include <net/if.h>
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#include <net/bpf.h>
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52
#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stddef.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 <limits.h>
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#include <ifaddrs.h>
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#include "defs.h"
64
65
static int BpfFd = -1;
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static unsigned int BpfLen = 0;
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static u_int8_t *BpfPkt = NULL;
68
69
/*
70
**  BpfOpen -- Open and initialize a BPF device.
71
**
72
**	Parameters:
73
**		None.
74
**
75
**	Returns:
76
**		File descriptor of opened BPF device
77
**
78
**	Side Effects:
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**		If an error is encountered, the program terminates here.
80
*/
81
int
82
BpfOpen(void)
83
{
84
	struct ifreq ifr;
85
	int n;
86
87
	if ((BpfFd = open("/dev/bpf", O_RDWR)) == -1) {
88
		syslog(LOG_ERR, "bpf: can't open device: %m");
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		DoExit();
90
	}
91
92
	/*
93
	 *  Set interface name for bpf device, get data link layer
94
	 *  type and make sure it's type Ethernet.
95
	 */
96
	(void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name));
97
	if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) {
98
		syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName);
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		DoExit();
100
	}
101
102
	/*
103
	 *  Make sure we are dealing with an Ethernet device.
104
	 */
105
	if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) {
106
		syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m");
107
		DoExit();
108
	}
109
	if (n != DLT_EN10MB) {
110
		syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported",
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		    IntfName, n);
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		DoExit();
113
	}
114
115
	/*
116
	 *  On read(), return packets immediately (do not buffer them).
117
	 */
118
	n = 1;
119
	if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) {
120
		syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m");
121
		DoExit();
122
	}
123
124
	/*
125
	 *  Try to enable the chip/driver's multicast address filter to
126
	 *  grab our RMP address.  If this fails, try promiscuous mode.
127
	 *  If this fails, there's no way we are going to get any RMP
128
	 *  packets so just exit here.
129
	 */
130
#ifdef MSG_EOR
131
	ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
132
#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, SIOCADDMULTI, (caddr_t)&ifr) < 0) {
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		syslog(LOG_WARNING,
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		    "bpf: can't add mcast addr (%m), setting promiscuous mode");
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139
		if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) {
140
			syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m");
141
			DoExit();
142
		}
143
	}
144
145
	/*
146
	 *  Ask BPF how much buffer space it requires and allocate one.
147
	 */
148
	if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) {
149
		syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m");
150
		DoExit();
151
	}
152
	if (BpfPkt == NULL)
153
		BpfPkt = malloc(BpfLen);
154
155
	if (BpfPkt == NULL) {
156
		syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)",
157
		    BpfLen);
158
		DoExit();
159
	}
160
161
	/*
162
	 *  Write a little program to snarf RMP Boot packets and stuff
163
	 *  it down BPF's throat (i.e. set up the packet filter).
164
	 */
165
	{
166
#define	RMP(field)	offsetof(struct rmp_packet, field)
167
		static struct bpf_insn bpf_insn[] = {
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		    /* make sure it is a 802.3 packet */
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		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, RMP(hp_hdr.len) },
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		    { BPF_JMP|BPF_JGE|BPF_K, 7, 0, 0x600 },
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172
		    { BPF_LD|BPF_B|BPF_ABS,  0, 0, 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, 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, RMP(hp_llc.dxsap) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP },
178
		    { BPF_RET|BPF_K,         0, 0, RMP_MAX_PACKET },
179
		    { BPF_RET|BPF_K,         0, 0, 0x0 }
180
		};
181
182
		static struct bpf_insn bpf_wf_insn[] = {
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		    /* make sure it is a 802.3 packet */
184
		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, RMP(hp_hdr.len) },
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		    { BPF_JMP|BPF_JGE|BPF_K, 12, 0, 0x600 },
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187
		    /* check the SNAP header */
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		    { BPF_LD|BPF_B|BPF_ABS,  0, 0, RMP(hp_llc.dsap) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 10, IEEE_DSAP_HP },
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		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, RMP(hp_llc.cntrl) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 8, IEEE_CNTL_HP },
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		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, RMP(hp_llc.sxsap) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 6, HPEXT_DXSAP },
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		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, RMP(hp_llc.dxsap) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 4, HPEXT_SXSAP },
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198
		    /* check return type code */
199
		    { BPF_LD|BPF_B|BPF_ABS,  0, 0,
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		        RMP(rmp_proto.rmp_raw.rmp_type) },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 1, 0, RMP_BOOT_REPL },
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		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, RMP_READ_REPL },
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		    { BPF_RET|BPF_K,         0, 0, RMP_MAX_PACKET },
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		    { BPF_RET|BPF_K,         0, 0, 0x0 }
206
		};
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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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212
		static struct bpf_program bpf_w_pgm = {
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			sizeof(bpf_wf_insn)/sizeof(bpf_wf_insn[0]), bpf_wf_insn
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		};
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216
		if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) {
217
			syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m");
218
			DoExit();
219
		}
220
221
		if (ioctl(BpfFd, BIOCSETWF, (caddr_t)&bpf_w_pgm) < 0) {
222
			syslog(LOG_ERR, "bpf: ioctl(BIOCSETWF): %m");
223
			DoExit();
224
		}
225
226
		if (ioctl(BpfFd, BIOCLOCK) < 0) {
227
			syslog(LOG_ERR, "bpf: ioctl(BIOCLOCK): %m");
228
			DoExit();
229
		}
230
	}
231
232
	return(BpfFd);
233
}
234
235
/*
236
**  BPF GetIntfName -- Return the name of a network interface attached to
237
**		the system, or 0 if none can be found.  The interface
238
**		must be configured up; the lowest unit number is
239
**		preferred; loopback is ignored.
240
**
241
**	Parameters:
242
**		errmsg - if no network interface found, *errmsg explains why.
243
**
244
**	Returns:
245
**		A (static) pointer to interface name, or NULL on error.
246
**
247
**	Side Effects:
248
**		None.
249
*/
250
char *
251
BpfGetIntfName(char **errmsg)
252
{
253
	int minunit = 999, n;
254
	char *cp;
255
	const char *errstr;
256
	static char device[IFNAMSIZ];
257
	static char errbuf[128] = "No Error!";
258
	struct ifaddrs *ifap, *ifa, *mp = NULL;
259
260
	if (errmsg != NULL)
261
		*errmsg = errbuf;
262
263
	if (getifaddrs(&ifap) != 0) {
264
		(void) strlcpy(errbuf, "bpf: getifaddrs: %m", sizeof(errbuf));
265
		return(NULL);
266
	}
267
268
	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
269
		/*
270
		 *  If interface is down or this is the loopback interface,
271
		 *  ignore it.
272
		 */
273
		if ((ifa->ifa_flags & IFF_UP) == 0 ||
274
#ifdef IFF_LOOPBACK
275
		    (ifa->ifa_flags & IFF_LOOPBACK))
276
#else
277
		    (strcmp(ifa->ifa_name, "lo0") == 0))
278
#endif
279
			continue;
280
281
		for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp)
282
			;
283
		n = strtonum(cp, 0, INT_MAX, &errstr);
284
		if (errstr == NULL && n < minunit) {
285
			minunit = n;
286
			mp = ifa;
287
		}
288
	}
289
290
	if (mp == 0) {
291
		(void) strlcpy(errbuf, "bpf: no interfaces found",
292
		    sizeof(errbuf));
293
		freeifaddrs(ifap);
294
		return(NULL);
295
	}
296
297
	(void) strlcpy(device, mp->ifa_name, sizeof device);
298
	freeifaddrs(ifap);
299
	return(device);
300
}
301
302
/*
303
**  BpfRead -- Read packets from a BPF device and fill in `rconn'.
304
**
305
**	Parameters:
306
**		rconn - filled in with next packet.
307
**		doread - is True if we can issue a read() syscall.
308
**
309
**	Returns:
310
**		True if `rconn' contains a new packet, False otherwise.
311
**
312
**	Side Effects:
313
**		None.
314
*/
315
int
316
BpfRead(RMPCONN *rconn, int doread)
317
{
318
	int datlen, caplen, hdrlen;
319
	static u_int8_t *bp = NULL, *ep = NULL;
320
	int cc;
321
322
	/*
323
	 *  The read() may block, or it may return one or more packets.
324
	 *  We let the caller decide whether or not we can issue a read().
325
	 */
326
	if (doread) {
327
		if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) {
328
			syslog(LOG_ERR, "bpf: read: %m");
329
			return(0);
330
		} else {
331
			bp = BpfPkt;
332
			ep = BpfPkt + cc;
333
		}
334
	}
335
336
#define bhp ((struct bpf_hdr *)bp)
337
	/*
338
	 *  If there is a new packet in the buffer, stuff it into `rconn'
339
	 *  and return a success indication.
340
	 */
341
	if (bp < ep) {
342
		datlen = bhp->bh_datalen;
343
		caplen = bhp->bh_caplen;
344
		hdrlen = bhp->bh_hdrlen;
345
346
		if (caplen != datlen)
347
			syslog(LOG_ERR,
348
			    "bpf: short packet dropped (%d of %d bytes)",
349
			    caplen, datlen);
350
		else if (caplen > sizeof(struct rmp_packet))
351
			syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)",
352
			    caplen);
353
		else {
354
			rconn->rmplen = caplen;
355
			rconn->tstamp.tv_sec = bhp->bh_tstamp.tv_sec;
356
			rconn->tstamp.tv_usec = bhp->bh_tstamp.tv_usec;
357
			bcopy((char *)bp + hdrlen, (char *)&rconn->rmp, caplen);
358
		}
359
		bp += BPF_WORDALIGN(caplen + hdrlen);
360
		return(1);
361
	}
362
#undef bhp
363
364
	return(0);
365
}
366
367
/*
368
**  BpfWrite -- Write packet to BPF device.
369
**
370
**	Parameters:
371
**		rconn - packet to send.
372
**
373
**	Returns:
374
**		True if write succeeded, False otherwise.
375
**
376
**	Side Effects:
377
**		None.
378
*/
379
int
380
BpfWrite(RMPCONN *rconn)
381
{
382
	if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) {
383
		syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn));
384
		return(0);
385
	}
386
387
	return(1);
388
}