1/*
2 * Copyright (c) 1988, 1992 The University of Utah and the Center
3 *	for Software Science (CSS).
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * the Center for Software Science of the University of Utah Computer
9 * Science Department.  CSS requests users of this software to return
10 * to css-dist@cs.utah.edu any improvements that they make and grant
11 * CSS redistribution rights.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 *    must display the following acknowledgement:
23 *	This product includes software developed by the University of
24 *	California, Berkeley and its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 *    may be used to endorse or promote products derived from this software
27 *    without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * SUCH DAMAGE.
40 *
41 *	from: @(#)bpf.c	8.1 (Berkeley) 6/4/93
42 *
43 * From: Utah Hdr: bpf.c 3.1 92/07/06
44 * Author: Jeff Forys, University of Utah CSS
45 */
46
47#ifndef lint
48#if 0
49static const char sccsid[] = "@(#)bpf.c	8.1 (Berkeley) 6/4/93";
50#endif
51static const char rcsid[] =
52  "$FreeBSD$";
53#endif /* not lint */
54
55#include <sys/param.h>
56#include <sys/ioctl.h>
57#include <sys/socket.h>
58#include <sys/time.h>
59
60#include <net/if.h>
61#include <net/bpf.h>
62
63#include <ctype.h>
64#include <errno.h>
65#include <fcntl.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <syslog.h>
70#include <unistd.h>
71#include "defs.h"
72#include "pathnames.h"
73
74static int BpfFd = -1;
75static unsigned BpfLen = 0;
76static u_int8_t *BpfPkt = NULL;
77
78/*
79**  BpfOpen -- Open and initialize a BPF device.
80**
81**	Parameters:
82**		None.
83**
84**	Returns:
85**		File descriptor of opened BPF device (for select() etc).
86**
87**	Side Effects:
88**		If an error is encountered, the program terminates here.
89*/
90int
91BpfOpen(void)
92{
93	struct ifreq ifr;
94	char bpfdev[32];
95	int n = 0;
96
97	/*
98	 *  Open the first available BPF device.
99	 */
100	do {
101		(void) sprintf(bpfdev, _PATH_BPF, n++);
102		BpfFd = open(bpfdev, O_RDWR);
103	} while (BpfFd < 0 && (errno == EBUSY || errno == EPERM));
104
105	if (BpfFd < 0) {
106		syslog(LOG_ERR, "bpf: no available devices: %m");
107		Exit(0);
108	}
109
110	/*
111	 *  Set interface name for bpf device, get data link layer
112	 *  type and make sure it's type Ethernet.
113	 */
114	(void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name));
115	if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) {
116		syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName);
117		Exit(0);
118	}
119
120	/*
121	 *  Make sure we are dealing with an Ethernet device.
122	 */
123	if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) {
124		syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m");
125		Exit(0);
126	}
127	if (n != DLT_EN10MB) {
128		syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported",
129		       IntfName, n);
130		Exit(0);
131	}
132
133	/*
134	 *  On read(), return packets immediately (do not buffer them).
135	 */
136	n = 1;
137	if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) {
138		syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m");
139		Exit(0);
140	}
141
142	/*
143	 *  Try to enable the chip/driver's multicast address filter to
144	 *  grab our RMP address.  If this fails, try promiscuous mode.
145	 *  If this fails, there's no way we are going to get any RMP
146	 *  packets so just exit here.
147	 */
148#ifdef MSG_EOR
149	ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
150#endif
151	ifr.ifr_addr.sa_family = AF_UNSPEC;
152	memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
153	if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) {
154		syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m");
155		Exit(0);
156	}
157
158	/*
159	 *  Ask BPF how much buffer space it requires and allocate one.
160	 */
161	if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) {
162		syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m");
163		Exit(0);
164	}
165	if (BpfPkt == NULL)
166		BpfPkt = (u_int8_t *)malloc(BpfLen);
167
168	if (BpfPkt == NULL) {
169		syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)",
170		       BpfLen);
171		Exit(0);
172	}
173
174	/*
175	 *  Write a little program to snarf RMP Boot packets and stuff
176	 *  it down BPF's throat (i.e. set up the packet filter).
177	 */
178	{
179#define	RMP	((struct rmp_packet *)0)
180		static struct bpf_insn bpf_insn[] = {
181		    { BPF_LD|BPF_B|BPF_ABS,  0, 0, (long)&RMP->hp_llc.dsap },
182		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP },
183		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, (long)&RMP->hp_llc.cntrl },
184		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP },
185		    { BPF_LD|BPF_H|BPF_ABS,  0, 0, (long)&RMP->hp_llc.dxsap },
186		    { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP },
187		    { BPF_RET|BPF_K,         0, 0, RMP_MAX_PACKET },
188		    { BPF_RET|BPF_K,         0, 0, 0x0 }
189		};
190#undef	RMP
191		static struct bpf_program bpf_pgm = {
192		    sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn
193		};
194
195		if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) {
196			syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m");
197			Exit(0);
198		}
199	}
200
201	return(BpfFd);
202}
203
204/*
205**  BPF GetIntfName -- Return the name of a network interface attached to
206**		the system, or 0 if none can be found.  The interface
207**		must be configured up; the lowest unit number is
208**		preferred; loopback is ignored.
209**
210**	Parameters:
211**		errmsg - if no network interface found, *errmsg explains why.
212**
213**	Returns:
214**		A (static) pointer to interface name, or NULL on error.
215**
216**	Side Effects:
217**		None.
218*/
219char *
220BpfGetIntfName(char **errmsg)
221{
222	struct ifreq ibuf[8], *ifrp, *ifend, *mp;
223	struct ifconf ifc;
224	int fd;
225	int minunit, n;
226	char *cp;
227	static char device[sizeof(ifrp->ifr_name)];
228	static char errbuf[128] = "No Error!";
229
230	if (errmsg != NULL)
231		*errmsg = errbuf;
232
233	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
234		(void) strcpy(errbuf, "bpf: socket: %m");
235		return(NULL);
236	}
237	ifc.ifc_len = sizeof ibuf;
238	ifc.ifc_buf = (caddr_t)ibuf;
239
240#ifdef OSIOCGIFCONF
241	if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 ||
242	    ifc.ifc_len < sizeof(struct ifreq)) {
243		(void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m");
244		return(NULL);
245	}
246#else
247	if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
248	    ifc.ifc_len < sizeof(struct ifreq)) {
249		(void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m");
250		return(NULL);
251	}
252#endif
253	ifrp = ibuf;
254	ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
255
256	mp = 0;
257	minunit = 666;
258	for (; ifrp < ifend; ++ifrp) {
259		if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) {
260			(void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m");
261			return(NULL);
262		}
263
264		/*
265		 *  If interface is down or this is the loopback interface,
266		 *  ignore it.
267		 */
268		if ((ifrp->ifr_flags & IFF_UP) == 0 ||
269#ifdef IFF_LOOPBACK
270		    (ifrp->ifr_flags & IFF_LOOPBACK))
271#else
272		    (strcmp(ifrp->ifr_name, "lo0") == 0))
273#endif
274			continue;
275
276		for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
277			;
278		n = atoi(cp);
279		if (n < minunit) {
280			minunit = n;
281			mp = ifrp;
282		}
283	}
284
285	(void) close(fd);
286	if (mp == 0) {
287		(void) strcpy(errbuf, "bpf: no interfaces found");
288		return(NULL);
289	}
290
291	(void) strcpy(device, mp->ifr_name);
292	return(device);
293}
294
295/*
296**  BpfRead -- Read packets from a BPF device and fill in `rconn'.
297**
298**	Parameters:
299**		rconn - filled in with next packet.
300**		doread - is True if we can issue a read() syscall.
301**
302**	Returns:
303**		True if `rconn' contains a new packet, False otherwise.
304**
305**	Side Effects:
306**		None.
307*/
308int
309BpfRead(RMPCONN *rconn, int doread)
310{
311	int datlen, caplen, hdrlen;
312	static u_int8_t *bp = NULL, *ep = NULL;
313	int cc;
314
315	/*
316	 *  The read() may block, or it may return one or more packets.
317	 *  We let the caller decide whether or not we can issue a read().
318	 */
319	if (doread) {
320		if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) {
321			syslog(LOG_ERR, "bpf: read: %m");
322			return(0);
323		} else {
324			bp = BpfPkt;
325			ep = BpfPkt + cc;
326		}
327	}
328
329#define bhp ((struct bpf_hdr *)bp)
330	/*
331	 *  If there is a new packet in the buffer, stuff it into `rconn'
332	 *  and return a success indication.
333	 */
334	if (bp < ep) {
335		datlen = bhp->bh_datalen;
336		caplen = bhp->bh_caplen;
337		hdrlen = bhp->bh_hdrlen;
338
339		if (caplen != datlen)
340			syslog(LOG_ERR,
341			       "bpf: short packet dropped (%d of %d bytes)",
342			       caplen, datlen);
343		else if (caplen > sizeof(struct rmp_packet))
344			syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)",
345			       caplen);
346		else {
347			rconn->rmplen = caplen;
348			memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp,
349			      sizeof(struct timeval));
350			memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen);
351		}
352		bp += BPF_WORDALIGN(caplen + hdrlen);
353		return(1);
354	}
355#undef bhp
356
357	return(0);
358}
359
360/*
361**  BpfWrite -- Write packet to BPF device.
362**
363**	Parameters:
364**		rconn - packet to send.
365**
366**	Returns:
367**		True if write succeeded, False otherwise.
368**
369**	Side Effects:
370**		None.
371*/
372int
373BpfWrite(RMPCONN *rconn)
374{
375	if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) {
376		syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn));
377		return(0);
378	}
379
380	return(1);
381}
382
383/*
384**  BpfClose -- Close a BPF device.
385**
386**	Parameters:
387**		None.
388**
389**	Returns:
390**		Nothing.
391**
392**	Side Effects:
393**		None.
394*/
395void
396BpfClose(void)
397{
398	struct ifreq ifr;
399
400	if (BpfPkt != NULL) {
401		free((char *)BpfPkt);
402		BpfPkt = NULL;
403	}
404
405	if (BpfFd == -1)
406		return;
407
408#ifdef MSG_EOR
409	ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
410#endif
411	ifr.ifr_addr.sa_family = AF_UNSPEC;
412	memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
413	if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0)
414		(void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0);
415
416	(void) close(BpfFd);
417	BpfFd = -1;
418}
419