1 /* $NetBSD: bpf.c,v 1.10 2000/04/13 08:52:44 itojun 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 1.10 2000/04/13 08:52:44 itojun 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 (getifaddrs(&ifap) != 0) { 237 (void) strcpy(errbuf, "bpf: getifaddrs: %m"); 238 return(NULL); 239 } 240 241 p = NULL; 242 minunit = 666; 243 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 244 /* 245 * If interface is down or this is the loopback interface, 246 * ignore it. 247 */ 248 if ((ifa->ifa_flags & IFF_UP) == 0 || 249 #ifdef IFF_LOOPBACK 250 (ifa->ifa_flags & IFF_LOOPBACK)) 251 #else 252 (strcmp(ifa->ifa_name, "lo0") == 0)) 253 #endif 254 continue; 255 256 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 257 ; 258 n = atoi(cp); 259 if (n < minunit) { 260 minunit = n; 261 p = ifa; 262 } 263 } 264 if (p == NULL) { 265 (void) strcpy(errbuf, "bpf: no interfaces found"); 266 freeifaddrs(ifap); 267 return(NULL); 268 } 269 270 (void) strncpy(device, p->ifa_name, sizeof(device)); 271 device[sizeof(device) - 1] = '\0'; 272 freeifaddrs(ifap); 273 return(device); 274 #else 275 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 276 struct ifconf ifc; 277 int fd; 278 int minunit, n; 279 char *cp; 280 static char device[sizeof(ifrp->ifr_name)]; 281 static char errbuf[128] = "No Error!"; 282 283 if (errmsg != NULL) 284 *errmsg = errbuf; 285 286 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 287 (void) strcpy(errbuf, "bpf: socket: %m"); 288 return(NULL); 289 } 290 ifc.ifc_len = sizeof ibuf; 291 ifc.ifc_buf = (caddr_t)ibuf; 292 293 #ifdef OSIOCGIFCONF 294 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 295 ifc.ifc_len < sizeof(struct ifreq)) { 296 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 297 return(NULL); 298 } 299 #else 300 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 301 ifc.ifc_len < sizeof(struct ifreq)) { 302 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 303 return(NULL); 304 } 305 #endif 306 ifrp = ibuf; 307 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 308 309 mp = 0; 310 minunit = 666; 311 for (; ifrp < ifend; ++ifrp) { 312 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 313 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 314 return(NULL); 315 } 316 317 /* 318 * If interface is down or this is the loopback interface, 319 * ignore it. 320 */ 321 if ((ifrp->ifr_flags & IFF_UP) == 0 || 322 #ifdef IFF_LOOPBACK 323 (ifrp->ifr_flags & IFF_LOOPBACK)) 324 #else 325 (strcmp(ifrp->ifr_name, "lo0") == 0)) 326 #endif 327 continue; 328 329 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 330 ; 331 n = atoi(cp); 332 if (n < minunit) { 333 minunit = n; 334 mp = ifrp; 335 } 336 } 337 338 (void) close(fd); 339 if (mp == 0) { 340 (void) strcpy(errbuf, "bpf: no interfaces found"); 341 return(NULL); 342 } 343 344 (void) strcpy(device, mp->ifr_name); 345 return(device); 346 #endif 347 } 348 349 /* 350 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 351 ** 352 ** Parameters: 353 ** rconn - filled in with next packet. 354 ** doread - is True if we can issue a read() syscall. 355 ** 356 ** Returns: 357 ** True if `rconn' contains a new packet, False otherwise. 358 ** 359 ** Side Effects: 360 ** None. 361 */ 362 int 363 BpfRead(rconn, doread) 364 RMPCONN *rconn; 365 int doread; 366 { 367 int datlen, caplen, hdrlen; 368 static u_int8_t *bp = NULL, *ep = NULL; 369 int cc; 370 371 /* 372 * The read() may block, or it may return one or more packets. 373 * We let the caller decide whether or not we can issue a read(). 374 */ 375 if (doread) { 376 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 377 syslog(LOG_ERR, "bpf: read: %m"); 378 return(0); 379 } else { 380 bp = BpfPkt; 381 ep = BpfPkt + cc; 382 } 383 } 384 385 #define bhp ((struct bpf_hdr *)bp) 386 /* 387 * If there is a new packet in the buffer, stuff it into `rconn' 388 * and return a success indication. 389 */ 390 if (bp < ep) { 391 datlen = bhp->bh_datalen; 392 caplen = bhp->bh_caplen; 393 hdrlen = bhp->bh_hdrlen; 394 395 if (caplen != datlen) 396 syslog(LOG_ERR, 397 "bpf: short packet dropped (%d of %d bytes)", 398 caplen, datlen); 399 else if (caplen > sizeof(struct rmp_packet)) 400 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 401 caplen); 402 else { 403 rconn->rmplen = caplen; 404 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 405 sizeof(struct timeval)); 406 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, 407 caplen); 408 } 409 bp += BPF_WORDALIGN(caplen + hdrlen); 410 return(1); 411 } 412 #undef bhp 413 414 return(0); 415 } 416 417 /* 418 ** BpfWrite -- Write packet to BPF device. 419 ** 420 ** Parameters: 421 ** rconn - packet to send. 422 ** 423 ** Returns: 424 ** True if write succeeded, False otherwise. 425 ** 426 ** Side Effects: 427 ** None. 428 */ 429 int 430 BpfWrite(rconn) 431 RMPCONN *rconn; 432 { 433 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 434 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 435 return(0); 436 } 437 438 return(1); 439 } 440 441 /* 442 ** BpfClose -- Close a BPF device. 443 ** 444 ** Parameters: 445 ** None. 446 ** 447 ** Returns: 448 ** Nothing. 449 ** 450 ** Side Effects: 451 ** None. 452 */ 453 void 454 BpfClose() 455 { 456 struct ifreq ifr; 457 458 if (BpfPkt != NULL) { 459 free((char *)BpfPkt); 460 BpfPkt = NULL; 461 } 462 463 if (BpfFd == -1) 464 return; 465 466 #ifdef MSG_EOR 467 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 468 #endif 469 ifr.ifr_addr.sa_family = AF_UNSPEC; 470 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 471 RMP_ADDRLEN); 472 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 473 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 474 475 (void) close(BpfFd); 476 BpfFd = -1; 477 } 478