1 /* $NetBSD: bpf.c,v 1.11 2001/02/05 02:37:34 lukem Exp $ */ 2 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 css-dist@cs.utah.edu 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. All advertising materials mentioning features or use of this software 24 * must display the following acknowledgement: 25 * This product includes software developed by the University of 26 * California, Berkeley and its contributors. 27 * 4. Neither the name of the University nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 * 43 * from: @(#)bpf.c 8.1 (Berkeley) 6/4/93 44 * 45 * From: Utah Hdr: bpf.c 3.1 92/07/06 46 * Author: Jeff Forys, University of Utah CSS 47 */ 48 49 #include <sys/cdefs.h> 50 #ifndef lint 51 #if 0 52 static char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93"; 53 #else 54 __RCSID("$NetBSD: bpf.c,v 1.11 2001/02/05 02:37:34 lukem Exp $"); 55 #endif 56 #endif /* not lint */ 57 58 #include <sys/param.h> 59 #include <sys/ioctl.h> 60 #include <sys/socket.h> 61 62 #include <net/if.h> 63 #include <net/bpf.h> 64 65 #include <ctype.h> 66 #include <errno.h> 67 #include <fcntl.h> 68 #include <stdio.h> 69 #include <stdlib.h> 70 #include <string.h> 71 #include <syslog.h> 72 #include <unistd.h> 73 #ifdef HAVE_IFADDRS_H 74 #include <ifaddrs.h> 75 #endif 76 #include "defs.h" 77 #include "pathnames.h" 78 79 static int BpfFd = -1; 80 static unsigned BpfLen = 0; 81 static u_int8_t *BpfPkt = NULL; 82 83 /* 84 ** BpfOpen -- Open and initialize a BPF device. 85 ** 86 ** Parameters: 87 ** None. 88 ** 89 ** Returns: 90 ** File descriptor of opened BPF device (for select() etc). 91 ** 92 ** Side Effects: 93 ** If an error is encountered, the program terminates here. 94 */ 95 int 96 BpfOpen() 97 { 98 struct ifreq ifr; 99 char bpfdev[32]; 100 int n = 0; 101 102 /* 103 * Open the first available BPF device. 104 */ 105 do { 106 (void) sprintf(bpfdev, _PATH_BPF, n++); 107 BpfFd = open(bpfdev, O_RDWR); 108 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 109 110 if (BpfFd < 0) { 111 syslog(LOG_ERR, "bpf: no available devices: %m"); 112 Exit(0); 113 } 114 115 /* 116 * Set interface name for bpf device, get data link layer 117 * type and make sure it's type Ethernet. 118 */ 119 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 120 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 121 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 122 Exit(0); 123 } 124 125 /* 126 * Make sure we are dealing with an Ethernet device. 127 */ 128 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 129 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 130 Exit(0); 131 } 132 if (n != DLT_EN10MB) { 133 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 134 IntfName, n); 135 Exit(0); 136 } 137 138 /* 139 * On read(), return packets immediately (do not buffer them). 140 */ 141 n = 1; 142 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 143 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 144 Exit(0); 145 } 146 147 /* 148 * Try to enable the chip/driver's multicast address filter to 149 * grab our RMP address. If this fails, try promiscuous mode. 150 * If this fails, there's no way we are going to get any RMP 151 * packets so just exit here. 152 */ 153 #ifdef MSG_EOR 154 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 155 #endif 156 ifr.ifr_addr.sa_family = AF_UNSPEC; 157 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 158 RMP_ADDRLEN); 159 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 160 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 161 Exit(0); 162 } 163 164 /* 165 * Ask BPF how much buffer space it requires and allocate one. 166 */ 167 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 168 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 169 Exit(0); 170 } 171 if (BpfPkt == NULL) 172 BpfPkt = (u_int8_t *)malloc(BpfLen); 173 174 if (BpfPkt == NULL) { 175 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 176 BpfLen); 177 Exit(0); 178 } 179 180 /* 181 * Write a little program to snarf RMP Boot packets and stuff 182 * it down BPF's throat (i.e. set up the packet filter). 183 */ 184 { 185 #define RMP ((struct rmp_packet *)0) 186 static struct bpf_insn bpf_insn[] = { 187 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 188 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 189 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 190 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 191 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 192 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 193 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 194 { BPF_RET|BPF_K, 0, 0, 0x0 } 195 }; 196 #undef RMP 197 static struct bpf_program bpf_pgm = { 198 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 199 }; 200 201 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 202 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 203 Exit(0); 204 } 205 } 206 207 return(BpfFd); 208 } 209 210 /* 211 ** BPF GetIntfName -- Return the name of a network interface attached to 212 ** the system, or 0 if none can be found. The interface 213 ** must be configured up; the lowest unit number is 214 ** preferred; loopback is ignored. 215 ** 216 ** Parameters: 217 ** errmsg - if no network interface found, *errmsg explains why. 218 ** 219 ** Returns: 220 ** A (static) pointer to interface name, or NULL on error. 221 ** 222 ** Side Effects: 223 ** None. 224 */ 225 char * 226 BpfGetIntfName(errmsg) 227 char **errmsg; 228 { 229 #ifdef HAVE_IFADDRS_H 230 struct ifaddrs *ifap, *ifa, *p; 231 int minunit, n; 232 char *cp; 233 static char device[IFNAMSIZ + 1]; 234 static char errbuf[128] = "No Error!"; 235 236 if (errmsg != NULL) 237 *errmsg = errbuf; 238 239 if (getifaddrs(&ifap) != 0) { 240 (void) strcpy(errbuf, "bpf: getifaddrs: %m"); 241 return(NULL); 242 } 243 244 p = NULL; 245 minunit = 666; 246 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 247 /* 248 * If interface is down or this is the loopback interface, 249 * ignore it. 250 */ 251 if ((ifa->ifa_flags & IFF_UP) == 0 || 252 #ifdef IFF_LOOPBACK 253 (ifa->ifa_flags & IFF_LOOPBACK)) 254 #else 255 (strcmp(ifa->ifa_name, "lo0") == 0)) 256 #endif 257 continue; 258 259 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 260 ; 261 n = atoi(cp); 262 if (n < minunit) { 263 minunit = n; 264 p = ifa; 265 } 266 } 267 if (p == NULL) { 268 (void) strcpy(errbuf, "bpf: no interfaces found"); 269 freeifaddrs(ifap); 270 return(NULL); 271 } 272 273 (void) strncpy(device, p->ifa_name, sizeof(device)); 274 device[sizeof(device) - 1] = '\0'; 275 freeifaddrs(ifap); 276 return(device); 277 #else 278 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 279 struct ifconf ifc; 280 int fd; 281 int minunit, n; 282 char *cp; 283 static char device[sizeof(ifrp->ifr_name)]; 284 static char errbuf[128] = "No Error!"; 285 286 if (errmsg != NULL) 287 *errmsg = errbuf; 288 289 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 290 (void) strcpy(errbuf, "bpf: socket: %m"); 291 return(NULL); 292 } 293 ifc.ifc_len = sizeof ibuf; 294 ifc.ifc_buf = (caddr_t)ibuf; 295 296 #ifdef OSIOCGIFCONF 297 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 298 ifc.ifc_len < sizeof(struct ifreq)) { 299 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 300 return(NULL); 301 } 302 #else 303 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 304 ifc.ifc_len < sizeof(struct ifreq)) { 305 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 306 return(NULL); 307 } 308 #endif 309 ifrp = ibuf; 310 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 311 312 mp = 0; 313 minunit = 666; 314 for (; ifrp < ifend; ++ifrp) { 315 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 316 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 317 return(NULL); 318 } 319 320 /* 321 * If interface is down or this is the loopback interface, 322 * ignore it. 323 */ 324 if ((ifrp->ifr_flags & IFF_UP) == 0 || 325 #ifdef IFF_LOOPBACK 326 (ifrp->ifr_flags & IFF_LOOPBACK)) 327 #else 328 (strcmp(ifrp->ifr_name, "lo0") == 0)) 329 #endif 330 continue; 331 332 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 333 ; 334 n = atoi(cp); 335 if (n < minunit) { 336 minunit = n; 337 mp = ifrp; 338 } 339 } 340 341 (void) close(fd); 342 if (mp == 0) { 343 (void) strcpy(errbuf, "bpf: no interfaces found"); 344 return(NULL); 345 } 346 347 (void) strcpy(device, mp->ifr_name); 348 return(device); 349 #endif 350 } 351 352 /* 353 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 354 ** 355 ** Parameters: 356 ** rconn - filled in with next packet. 357 ** doread - is True if we can issue a read() syscall. 358 ** 359 ** Returns: 360 ** True if `rconn' contains a new packet, False otherwise. 361 ** 362 ** Side Effects: 363 ** None. 364 */ 365 int 366 BpfRead(rconn, doread) 367 RMPCONN *rconn; 368 int doread; 369 { 370 int datlen, caplen, hdrlen; 371 static u_int8_t *bp = NULL, *ep = NULL; 372 int cc; 373 374 /* 375 * The read() may block, or it may return one or more packets. 376 * We let the caller decide whether or not we can issue a read(). 377 */ 378 if (doread) { 379 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 380 syslog(LOG_ERR, "bpf: read: %m"); 381 return(0); 382 } else { 383 bp = BpfPkt; 384 ep = BpfPkt + cc; 385 } 386 } 387 388 #define bhp ((struct bpf_hdr *)bp) 389 /* 390 * If there is a new packet in the buffer, stuff it into `rconn' 391 * and return a success indication. 392 */ 393 if (bp < ep) { 394 datlen = bhp->bh_datalen; 395 caplen = bhp->bh_caplen; 396 hdrlen = bhp->bh_hdrlen; 397 398 if (caplen != datlen) 399 syslog(LOG_ERR, 400 "bpf: short packet dropped (%d of %d bytes)", 401 caplen, datlen); 402 else if (caplen > sizeof(struct rmp_packet)) 403 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 404 caplen); 405 else { 406 rconn->rmplen = caplen; 407 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 408 sizeof(struct timeval)); 409 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, 410 caplen); 411 } 412 bp += BPF_WORDALIGN(caplen + hdrlen); 413 return(1); 414 } 415 #undef bhp 416 417 return(0); 418 } 419 420 /* 421 ** BpfWrite -- Write packet to BPF device. 422 ** 423 ** Parameters: 424 ** rconn - packet to send. 425 ** 426 ** Returns: 427 ** True if write succeeded, False otherwise. 428 ** 429 ** Side Effects: 430 ** None. 431 */ 432 int 433 BpfWrite(rconn) 434 RMPCONN *rconn; 435 { 436 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 437 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 438 return(0); 439 } 440 441 return(1); 442 } 443 444 /* 445 ** BpfClose -- Close a BPF device. 446 ** 447 ** Parameters: 448 ** None. 449 ** 450 ** Returns: 451 ** Nothing. 452 ** 453 ** Side Effects: 454 ** None. 455 */ 456 void 457 BpfClose() 458 { 459 struct ifreq ifr; 460 461 if (BpfPkt != NULL) { 462 free((char *)BpfPkt); 463 BpfPkt = NULL; 464 } 465 466 if (BpfFd == -1) 467 return; 468 469 #ifdef MSG_EOR 470 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 471 #endif 472 ifr.ifr_addr.sa_family = AF_UNSPEC; 473 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 474 RMP_ADDRLEN); 475 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 476 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 477 478 (void) close(BpfFd); 479 BpfFd = -1; 480 } 481