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
49 static const char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93";
50 #endif
51 static const char rcsid[] =
52 "$FreeBSD: stable/9/libexec/rbootd/bpf.c 90377 2002-02-07 23:57:01Z imp $";
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
74 static int BpfFd = -1;
75 static unsigned BpfLen = 0;
76 static 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 */
90 int
BpfOpen(void)91 BpfOpen(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 */
219 char *
BpfGetIntfName(char ** errmsg)220 BpfGetIntfName(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 */
308 int
BpfRead(RMPCONN * rconn,int doread)309 BpfRead(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 */
372 int
BpfWrite(RMPCONN * rconn)373 BpfWrite(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 */
395 void
BpfClose(void)396 BpfClose(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