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