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 * @(#)bpf.c 8.1 (Berkeley) 6/4/93
43 * $FreeBSD: src/libexec/rbootd/bpf.c,v 1.10 1999/08/28 00:09:44 peter Exp $
44 */
45
46 #include <sys/param.h>
47 #include <sys/ioctl.h>
48 #include <sys/socket.h>
49 #include <sys/time.h>
50
51 #include <net/if.h>
52 #include <net/bpf.h>
53
54 #include <ctype.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <syslog.h>
61 #include <unistd.h>
62 #include "defs.h"
63 #include "pathnames.h"
64
65 static int BpfFd = -1;
66 static unsigned BpfLen = 0;
67 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 (for select() etc).
77 **
78 ** Side Effects:
79 ** If an error is encountered, the program terminates here.
80 */
81 int
BpfOpen(void)82 BpfOpen(void)
83 {
84 struct ifreq ifr;
85 int n = 0;
86
87 /*
88 * Open the BPF device.
89 */
90 BpfFd = open(_PATH_BPF, O_RDWR);
91 if (BpfFd < 0) {
92 syslog(LOG_ERR, "bpf: no available devices: %m");
93 Exit(0);
94 }
95
96 /*
97 * Set interface name for bpf device, get data link layer
98 * type and make sure it's type Ethernet.
99 */
100 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name));
101 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) {
102 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName);
103 Exit(0);
104 }
105
106 /*
107 * Make sure we are dealing with an Ethernet device.
108 */
109 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) {
110 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m");
111 Exit(0);
112 }
113 if (n != DLT_EN10MB) {
114 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported",
115 IntfName, n);
116 Exit(0);
117 }
118
119 /*
120 * On read(), return packets immediately (do not buffer them).
121 */
122 n = 1;
123 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) {
124 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m");
125 Exit(0);
126 }
127
128 /*
129 * Try to enable the chip/driver's multicast address filter to
130 * grab our RMP address. If this fails, try promiscuous mode.
131 * If this fails, there's no way we are going to get any RMP
132 * packets so just exit here.
133 */
134 #ifdef MSG_EOR
135 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
136 #endif
137 ifr.ifr_addr.sa_family = AF_UNSPEC;
138 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
139 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) {
140 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m");
141 Exit(0);
142 }
143
144 /*
145 * Ask BPF how much buffer space it requires and allocate one.
146 */
147 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) {
148 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m");
149 Exit(0);
150 }
151 if (BpfPkt == NULL)
152 BpfPkt = (u_int8_t *)malloc(BpfLen);
153
154 if (BpfPkt == NULL) {
155 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)",
156 BpfLen);
157 Exit(0);
158 }
159
160 /*
161 * Write a little program to snarf RMP Boot packets and stuff
162 * it down BPF's throat (i.e. set up the packet filter).
163 */
164 {
165 #define RMP ((struct rmp_packet *)0)
166 static struct bpf_insn bpf_insn[] = {
167 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap },
168 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP },
169 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl },
170 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP },
171 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap },
172 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP },
173 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET },
174 { BPF_RET|BPF_K, 0, 0, 0x0 }
175 };
176 #undef RMP
177 static struct bpf_program bpf_pgm = {
178 NELEM(bpf_insn), bpf_insn
179 };
180
181 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) {
182 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m");
183 Exit(0);
184 }
185 }
186
187 return(BpfFd);
188 }
189
190 /*
191 ** BPF GetIntfName -- Return the name of a network interface attached to
192 ** the system, or 0 if none can be found. The interface
193 ** must be configured up; the lowest unit number is
194 ** preferred; loopback is ignored.
195 **
196 ** Parameters:
197 ** errmsg - if no network interface found, *errmsg explains why.
198 **
199 ** Returns:
200 ** A (static) pointer to interface name, or NULL on error.
201 **
202 ** Side Effects:
203 ** None.
204 */
205 char *
BpfGetIntfName(char ** errmsg)206 BpfGetIntfName(char **errmsg)
207 {
208 struct ifreq ibuf[8], *ifrp, *ifend, *mp;
209 struct ifconf ifc;
210 int fd;
211 int minunit, n;
212 char *cp;
213 static char device[sizeof(ifrp->ifr_name)];
214 static char errbuf[128] = "No Error!";
215
216 if (errmsg != NULL)
217 *errmsg = errbuf;
218
219 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
220 (void) strcpy(errbuf, "bpf: socket: %m");
221 return(NULL);
222 }
223 ifc.ifc_len = sizeof ibuf;
224 ifc.ifc_buf = (caddr_t)ibuf;
225
226 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
227 ifc.ifc_len < sizeof(struct ifreq)) {
228 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m");
229 return(NULL);
230 }
231 ifrp = ibuf;
232 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
233
234 mp = NULL;
235 minunit = 666;
236 for (; ifrp < ifend; ++ifrp) {
237 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) {
238 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m");
239 return(NULL);
240 }
241
242 /*
243 * If interface is down or this is the loopback interface,
244 * ignore it.
245 */
246 if ((ifrp->ifr_flags & IFF_UP) == 0 ||
247 #ifdef IFF_LOOPBACK
248 (ifrp->ifr_flags & IFF_LOOPBACK))
249 #else
250 (strcmp(ifrp->ifr_name, "lo0") == 0))
251 #endif
252 continue;
253
254 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
255 ;
256 n = atoi(cp);
257 if (n < minunit) {
258 minunit = n;
259 mp = ifrp;
260 }
261 }
262
263 (void) close(fd);
264 if (mp == NULL) {
265 (void) strcpy(errbuf, "bpf: no interfaces found");
266 return(NULL);
267 }
268
269 (void) strcpy(device, mp->ifr_name);
270 return(device);
271 }
272
273 /*
274 ** BpfRead -- Read packets from a BPF device and fill in `rconn'.
275 **
276 ** Parameters:
277 ** rconn - filled in with next packet.
278 ** doread - is True if we can issue a read() syscall.
279 **
280 ** Returns:
281 ** True if `rconn' contains a new packet, False otherwise.
282 **
283 ** Side Effects:
284 ** None.
285 */
286 int
BpfRead(RMPCONN * rconn,int doread)287 BpfRead(RMPCONN *rconn, int doread)
288 {
289 int datlen, caplen, hdrlen;
290 static u_int8_t *bp = NULL, *ep = NULL;
291 int cc;
292
293 /*
294 * The read() may block, or it may return one or more packets.
295 * We let the caller decide whether or not we can issue a read().
296 */
297 if (doread) {
298 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) {
299 syslog(LOG_ERR, "bpf: read: %m");
300 return(0);
301 } else {
302 bp = BpfPkt;
303 ep = BpfPkt + cc;
304 }
305 }
306
307 #define bhp ((struct bpf_hdr *)bp)
308 /*
309 * If there is a new packet in the buffer, stuff it into `rconn'
310 * and return a success indication.
311 */
312 if (bp < ep) {
313 datlen = bhp->bh_datalen;
314 caplen = bhp->bh_caplen;
315 hdrlen = bhp->bh_hdrlen;
316
317 if (caplen != datlen)
318 syslog(LOG_ERR,
319 "bpf: short packet dropped (%d of %d bytes)",
320 caplen, datlen);
321 else if (caplen > sizeof(struct rmp_packet))
322 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)",
323 caplen);
324 else {
325 rconn->rmplen = caplen;
326 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp,
327 sizeof(struct timeval));
328 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen);
329 }
330 bp += BPF_WORDALIGN(caplen + hdrlen);
331 return(1);
332 }
333 #undef bhp
334
335 return(0);
336 }
337
338 /*
339 ** BpfWrite -- Write packet to BPF device.
340 **
341 ** Parameters:
342 ** rconn - packet to send.
343 **
344 ** Returns:
345 ** True if write succeeded, False otherwise.
346 **
347 ** Side Effects:
348 ** None.
349 */
350 int
BpfWrite(RMPCONN * rconn)351 BpfWrite(RMPCONN *rconn)
352 {
353 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) {
354 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn));
355 return(0);
356 }
357
358 return(1);
359 }
360
361 /*
362 ** BpfClose -- Close a BPF device.
363 **
364 ** Parameters:
365 ** None.
366 **
367 ** Returns:
368 ** Nothing.
369 **
370 ** Side Effects:
371 ** None.
372 */
373 void
BpfClose(void)374 BpfClose(void)
375 {
376 struct ifreq ifr;
377
378 if (BpfPkt != NULL) {
379 free((char *)BpfPkt);
380 BpfPkt = NULL;
381 }
382
383 if (BpfFd == -1)
384 return;
385
386 #ifdef MSG_EOR
387 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
388 #endif
389 ifr.ifr_addr.sa_family = AF_UNSPEC;
390 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
391 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0)
392 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0);
393
394 (void) close(BpfFd);
395 BpfFd = -1;
396 }
397