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