1 /* $OpenBSD: bpf.c,v 1.5 2001/01/17 00:33:03 pjanzen Exp $ */ 2 /* $NetBSD: bpf.c,v 1.5.2.1 1995/11/14 08:45:42 thorpej Exp $ */ 3 4 /* 5 * Copyright (c) 1988, 1992 The University of Utah and the Center 6 * for Software Science (CSS). 7 * Copyright (c) 1992, 1993 8 * The Regents of the University of California. All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * the Center for Software Science of the University of Utah Computer 12 * Science Department. CSS requests users of this software to return 13 * to css-dist@cs.utah.edu any improvements that they make and grant 14 * CSS redistribution rights. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 3. All advertising materials mentioning features or use of this software 25 * must display the following acknowledgement: 26 * This product includes software developed by the University of 27 * California, Berkeley and its contributors. 28 * 4. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 * from: @(#)bpf.c 8.1 (Berkeley) 6/4/93 45 * 46 * From: Utah Hdr: bpf.c 3.1 92/07/06 47 * Author: Jeff Forys, University of Utah CSS 48 */ 49 50 #ifndef lint 51 /*static char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93";*/ 52 static char rcsid[] = "$OpenBSD: bpf.c,v 1.5 2001/01/17 00:33:03 pjanzen Exp $"; 53 #endif /* not lint */ 54 55 #include <sys/param.h> 56 #include <sys/ioctl.h> 57 #include <sys/socket.h> 58 59 #include <net/if.h> 60 #include <net/bpf.h> 61 62 #include <ctype.h> 63 #include <errno.h> 64 #include <fcntl.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <syslog.h> 69 #include <unistd.h> 70 #include "defs.h" 71 #include "pathnames.h" 72 73 static int BpfFd = -1; 74 static unsigned BpfLen = 0; 75 static u_int8_t *BpfPkt = NULL; 76 77 /* 78 ** BpfOpen -- Open and initialize a BPF device. 79 ** 80 ** Parameters: 81 ** None. 82 ** 83 ** Returns: 84 ** File descriptor of opened BPF device (for select() etc). 85 ** 86 ** Side Effects: 87 ** If an error is encountered, the program terminates here. 88 */ 89 int 90 BpfOpen() 91 { 92 struct ifreq ifr; 93 char bpfdev[32]; 94 int n = 0; 95 96 /* 97 * Open the first available BPF device. 98 */ 99 do { 100 (void) sprintf(bpfdev, _PATH_BPF, n++); 101 BpfFd = open(bpfdev, O_RDWR); 102 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 103 104 if (BpfFd < 0) { 105 syslog(LOG_ERR, "bpf: no available devices: %m"); 106 Exit(0); 107 } 108 109 /* 110 * Set interface name for bpf device, get data link layer 111 * type and make sure it's type Ethernet. 112 */ 113 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 114 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 115 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 116 Exit(0); 117 } 118 119 /* 120 * Make sure we are dealing with an Ethernet device. 121 */ 122 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 123 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 124 Exit(0); 125 } 126 if (n != DLT_EN10MB) { 127 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 128 IntfName, n); 129 Exit(0); 130 } 131 132 /* 133 * On read(), return packets immediately (do not buffer them). 134 */ 135 n = 1; 136 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 137 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 138 Exit(0); 139 } 140 141 /* 142 * Try to enable the chip/driver's multicast address filter to 143 * grab our RMP address. If this fails, try promiscuous mode. 144 * If this fails, there's no way we are going to get any RMP 145 * packets so just exit here. 146 */ 147 #ifdef MSG_EOR 148 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 149 #endif 150 ifr.ifr_addr.sa_family = AF_UNSPEC; 151 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 152 if (ioctl(BpfFd, SIOCADDMULTI, (caddr_t)&ifr) < 0) { 153 syslog(LOG_WARNING, 154 "bpf: can't add mcast addr (%m), setting promiscuous mode"); 155 156 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 157 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 158 Exit(0); 159 } 160 } 161 162 /* 163 * Ask BPF how much buffer space it requires and allocate one. 164 */ 165 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 166 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 167 Exit(0); 168 } 169 if (BpfPkt == NULL) 170 BpfPkt = (u_int8_t *)malloc(BpfLen); 171 172 if (BpfPkt == NULL) { 173 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 174 BpfLen); 175 Exit(0); 176 } 177 178 /* 179 * Write a little program to snarf RMP Boot packets and stuff 180 * it down BPF's throat (i.e. set up the packet filter). 181 */ 182 { 183 #define RMP ((struct rmp_packet *)0) 184 static struct bpf_insn bpf_insn[] = { 185 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 186 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 187 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 188 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 189 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 190 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 191 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 192 { BPF_RET|BPF_K, 0, 0, 0x0 } 193 }; 194 #undef RMP 195 static struct bpf_program bpf_pgm = { 196 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 197 }; 198 199 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 200 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 201 Exit(0); 202 } 203 } 204 205 return(BpfFd); 206 } 207 208 /* 209 ** BPF GetIntfName -- Return the name of a network interface attached to 210 ** the system, or 0 if none can be found. The interface 211 ** must be configured up; the lowest unit number is 212 ** preferred; loopback is ignored. 213 ** 214 ** Parameters: 215 ** errmsg - if no network interface found, *errmsg explains why. 216 ** 217 ** Returns: 218 ** A (static) pointer to interface name, or NULL on error. 219 ** 220 ** Side Effects: 221 ** None. 222 */ 223 char * 224 BpfGetIntfName(errmsg) 225 char **errmsg; 226 { 227 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 228 struct ifconf ifc; 229 int fd; 230 int minunit, n; 231 char *cp; 232 static char device[sizeof(ifrp->ifr_name)]; 233 static char errbuf[128] = "No Error!"; 234 235 if (errmsg != NULL) 236 *errmsg = errbuf; 237 238 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 239 (void) strlcpy(errbuf, "bpf: socket: %m", sizeof(errbuf)); 240 return(NULL); 241 } 242 ifc.ifc_len = sizeof ibuf; 243 ifc.ifc_buf = (caddr_t)ibuf; 244 245 #ifdef OSIOCGIFCONF 246 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 247 ifc.ifc_len < sizeof(struct ifreq)) { 248 (void) strlcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m", 249 sizeof (errbuf)); 250 return(NULL); 251 } 252 #else 253 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 254 ifc.ifc_len < sizeof(struct ifreq)) { 255 (void) strlcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m", 256 sizeof(errbuf)); 257 return(NULL); 258 } 259 #endif 260 ifrp = ibuf; 261 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 262 263 mp = 0; 264 minunit = 666; 265 for (; ifrp < ifend; ++ifrp) { 266 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 267 (void) strlcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m", 268 sizeof(errbuf)); 269 return(NULL); 270 } 271 272 /* 273 * If interface is down or this is the loopback interface, 274 * ignore it. 275 */ 276 if ((ifrp->ifr_flags & IFF_UP) == 0 || 277 #ifdef IFF_LOOPBACK 278 (ifrp->ifr_flags & IFF_LOOPBACK)) 279 #else 280 (strcmp(ifrp->ifr_name, "lo0") == 0)) 281 #endif 282 continue; 283 284 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 285 ; 286 n = atoi(cp); 287 if (n < minunit) { 288 minunit = n; 289 mp = ifrp; 290 } 291 } 292 293 (void) close(fd); 294 if (mp == 0) { 295 (void) strlcpy(errbuf, "bpf: no interfaces found", 296 sizeof(errbuf)); 297 return(NULL); 298 } 299 300 (void) strcpy(device, mp->ifr_name); 301 return(device); 302 } 303 304 /* 305 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 306 ** 307 ** Parameters: 308 ** rconn - filled in with next packet. 309 ** doread - is True if we can issue a read() syscall. 310 ** 311 ** Returns: 312 ** True if `rconn' contains a new packet, False otherwise. 313 ** 314 ** Side Effects: 315 ** None. 316 */ 317 int 318 BpfRead(rconn, doread) 319 RMPCONN *rconn; 320 int doread; 321 { 322 register int datlen, caplen, hdrlen; 323 static u_int8_t *bp = NULL, *ep = NULL; 324 int cc; 325 326 /* 327 * The read() may block, or it may return one or more packets. 328 * We let the caller decide whether or not we can issue a read(). 329 */ 330 if (doread) { 331 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 332 syslog(LOG_ERR, "bpf: read: %m"); 333 return(0); 334 } else { 335 bp = BpfPkt; 336 ep = BpfPkt + cc; 337 } 338 } 339 340 #define bhp ((struct bpf_hdr *)bp) 341 /* 342 * If there is a new packet in the buffer, stuff it into `rconn' 343 * and return a success indication. 344 */ 345 if (bp < ep) { 346 datlen = bhp->bh_datalen; 347 caplen = bhp->bh_caplen; 348 hdrlen = bhp->bh_hdrlen; 349 350 if (caplen != datlen) 351 syslog(LOG_ERR, 352 "bpf: short packet dropped (%d of %d bytes)", 353 caplen, datlen); 354 else if (caplen > sizeof(struct rmp_packet)) 355 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 356 caplen); 357 else { 358 rconn->rmplen = caplen; 359 bcopy((char *)&bhp->bh_tstamp, (char *)&rconn->tstamp, 360 sizeof(struct timeval)); 361 bcopy((char *)bp + hdrlen, (char *)&rconn->rmp, caplen); 362 } 363 bp += BPF_WORDALIGN(caplen + hdrlen); 364 return(1); 365 } 366 #undef bhp 367 368 return(0); 369 } 370 371 /* 372 ** BpfWrite -- Write packet to BPF device. 373 ** 374 ** Parameters: 375 ** rconn - packet to send. 376 ** 377 ** Returns: 378 ** True if write succeeded, False otherwise. 379 ** 380 ** Side Effects: 381 ** None. 382 */ 383 int 384 BpfWrite(rconn) 385 RMPCONN *rconn; 386 { 387 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 388 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 389 return(0); 390 } 391 392 return(1); 393 } 394 395 /* 396 ** BpfClose -- Close a BPF device. 397 ** 398 ** Parameters: 399 ** None. 400 ** 401 ** Returns: 402 ** Nothing. 403 ** 404 ** Side Effects: 405 ** None. 406 */ 407 void 408 BpfClose() 409 { 410 struct ifreq ifr; 411 412 if (BpfPkt != NULL) { 413 free((char *)BpfPkt); 414 BpfPkt = NULL; 415 } 416 417 if (BpfFd == -1) 418 return; 419 420 #ifdef MSG_EOR 421 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 422 #endif 423 ifr.ifr_addr.sa_family = AF_UNSPEC; 424 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 425 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 426 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 427 428 (void) close(BpfFd); 429 BpfFd = -1; 430 } 431