1 /* $NetBSD: bpf.c,v 1.9 1997/10/18 11:23:03 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 1.9 1997/10/18 11:23:03 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 #include "defs.h" 74 #include "pathnames.h" 75 76 static int BpfFd = -1; 77 static unsigned BpfLen = 0; 78 static u_int8_t *BpfPkt = NULL; 79 80 /* 81 ** BpfOpen -- Open and initialize a BPF device. 82 ** 83 ** Parameters: 84 ** None. 85 ** 86 ** Returns: 87 ** File descriptor of opened BPF device (for select() etc). 88 ** 89 ** Side Effects: 90 ** If an error is encountered, the program terminates here. 91 */ 92 int 93 BpfOpen() 94 { 95 struct ifreq ifr; 96 char bpfdev[32]; 97 int n = 0; 98 99 /* 100 * Open the first available BPF device. 101 */ 102 do { 103 (void) sprintf(bpfdev, _PATH_BPF, n++); 104 BpfFd = open(bpfdev, O_RDWR); 105 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 106 107 if (BpfFd < 0) { 108 syslog(LOG_ERR, "bpf: no available devices: %m"); 109 Exit(0); 110 } 111 112 /* 113 * Set interface name for bpf device, get data link layer 114 * type and make sure it's type Ethernet. 115 */ 116 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 117 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 118 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 119 Exit(0); 120 } 121 122 /* 123 * Make sure we are dealing with an Ethernet device. 124 */ 125 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 126 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 127 Exit(0); 128 } 129 if (n != DLT_EN10MB) { 130 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 131 IntfName, n); 132 Exit(0); 133 } 134 135 /* 136 * On read(), return packets immediately (do not buffer them). 137 */ 138 n = 1; 139 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 140 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 141 Exit(0); 142 } 143 144 /* 145 * Try to enable the chip/driver's multicast address filter to 146 * grab our RMP address. If this fails, try promiscuous mode. 147 * If this fails, there's no way we are going to get any RMP 148 * packets so just exit here. 149 */ 150 #ifdef MSG_EOR 151 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 152 #endif 153 ifr.ifr_addr.sa_family = AF_UNSPEC; 154 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 155 RMP_ADDRLEN); 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 * Ask BPF how much buffer space it requires and allocate one. 163 */ 164 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 165 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 166 Exit(0); 167 } 168 if (BpfPkt == NULL) 169 BpfPkt = (u_int8_t *)malloc(BpfLen); 170 171 if (BpfPkt == NULL) { 172 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 173 BpfLen); 174 Exit(0); 175 } 176 177 /* 178 * Write a little program to snarf RMP Boot packets and stuff 179 * it down BPF's throat (i.e. set up the packet filter). 180 */ 181 { 182 #define RMP ((struct rmp_packet *)0) 183 static struct bpf_insn bpf_insn[] = { 184 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 185 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 186 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 187 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 188 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 189 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 190 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 191 { BPF_RET|BPF_K, 0, 0, 0x0 } 192 }; 193 #undef RMP 194 static struct bpf_program bpf_pgm = { 195 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 196 }; 197 198 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 199 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 200 Exit(0); 201 } 202 } 203 204 return(BpfFd); 205 } 206 207 /* 208 ** BPF GetIntfName -- Return the name of a network interface attached to 209 ** the system, or 0 if none can be found. The interface 210 ** must be configured up; the lowest unit number is 211 ** preferred; loopback is ignored. 212 ** 213 ** Parameters: 214 ** errmsg - if no network interface found, *errmsg explains why. 215 ** 216 ** Returns: 217 ** A (static) pointer to interface name, or NULL on error. 218 ** 219 ** Side Effects: 220 ** None. 221 */ 222 char * 223 BpfGetIntfName(errmsg) 224 char **errmsg; 225 { 226 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 227 struct ifconf ifc; 228 int fd; 229 int minunit, n; 230 char *cp; 231 static char device[sizeof(ifrp->ifr_name)]; 232 static char errbuf[128] = "No Error!"; 233 234 if (errmsg != NULL) 235 *errmsg = errbuf; 236 237 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 238 (void) strcpy(errbuf, "bpf: socket: %m"); 239 return(NULL); 240 } 241 ifc.ifc_len = sizeof ibuf; 242 ifc.ifc_buf = (caddr_t)ibuf; 243 244 #ifdef OSIOCGIFCONF 245 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 246 ifc.ifc_len < sizeof(struct ifreq)) { 247 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 248 return(NULL); 249 } 250 #else 251 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 252 ifc.ifc_len < sizeof(struct ifreq)) { 253 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 254 return(NULL); 255 } 256 #endif 257 ifrp = ibuf; 258 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 259 260 mp = 0; 261 minunit = 666; 262 for (; ifrp < ifend; ++ifrp) { 263 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 264 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 265 return(NULL); 266 } 267 268 /* 269 * If interface is down or this is the loopback interface, 270 * ignore it. 271 */ 272 if ((ifrp->ifr_flags & IFF_UP) == 0 || 273 #ifdef IFF_LOOPBACK 274 (ifrp->ifr_flags & IFF_LOOPBACK)) 275 #else 276 (strcmp(ifrp->ifr_name, "lo0") == 0)) 277 #endif 278 continue; 279 280 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 281 ; 282 n = atoi(cp); 283 if (n < minunit) { 284 minunit = n; 285 mp = ifrp; 286 } 287 } 288 289 (void) close(fd); 290 if (mp == 0) { 291 (void) strcpy(errbuf, "bpf: no interfaces found"); 292 return(NULL); 293 } 294 295 (void) strcpy(device, mp->ifr_name); 296 return(device); 297 } 298 299 /* 300 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 301 ** 302 ** Parameters: 303 ** rconn - filled in with next packet. 304 ** doread - is True if we can issue a read() syscall. 305 ** 306 ** Returns: 307 ** True if `rconn' contains a new packet, False otherwise. 308 ** 309 ** Side Effects: 310 ** None. 311 */ 312 int 313 BpfRead(rconn, doread) 314 RMPCONN *rconn; 315 int doread; 316 { 317 int datlen, caplen, hdrlen; 318 static u_int8_t *bp = NULL, *ep = NULL; 319 int cc; 320 321 /* 322 * The read() may block, or it may return one or more packets. 323 * We let the caller decide whether or not we can issue a read(). 324 */ 325 if (doread) { 326 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 327 syslog(LOG_ERR, "bpf: read: %m"); 328 return(0); 329 } else { 330 bp = BpfPkt; 331 ep = BpfPkt + cc; 332 } 333 } 334 335 #define bhp ((struct bpf_hdr *)bp) 336 /* 337 * If there is a new packet in the buffer, stuff it into `rconn' 338 * and return a success indication. 339 */ 340 if (bp < ep) { 341 datlen = bhp->bh_datalen; 342 caplen = bhp->bh_caplen; 343 hdrlen = bhp->bh_hdrlen; 344 345 if (caplen != datlen) 346 syslog(LOG_ERR, 347 "bpf: short packet dropped (%d of %d bytes)", 348 caplen, datlen); 349 else if (caplen > sizeof(struct rmp_packet)) 350 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 351 caplen); 352 else { 353 rconn->rmplen = caplen; 354 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 355 sizeof(struct timeval)); 356 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, 357 caplen); 358 } 359 bp += BPF_WORDALIGN(caplen + hdrlen); 360 return(1); 361 } 362 #undef bhp 363 364 return(0); 365 } 366 367 /* 368 ** BpfWrite -- Write packet to BPF device. 369 ** 370 ** Parameters: 371 ** rconn - packet to send. 372 ** 373 ** Returns: 374 ** True if write succeeded, False otherwise. 375 ** 376 ** Side Effects: 377 ** None. 378 */ 379 int 380 BpfWrite(rconn) 381 RMPCONN *rconn; 382 { 383 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 384 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 385 return(0); 386 } 387 388 return(1); 389 } 390 391 /* 392 ** BpfClose -- Close a BPF device. 393 ** 394 ** Parameters: 395 ** None. 396 ** 397 ** Returns: 398 ** Nothing. 399 ** 400 ** Side Effects: 401 ** None. 402 */ 403 void 404 BpfClose() 405 { 406 struct ifreq ifr; 407 408 if (BpfPkt != NULL) { 409 free((char *)BpfPkt); 410 BpfPkt = NULL; 411 } 412 413 if (BpfFd == -1) 414 return; 415 416 #ifdef MSG_EOR 417 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 418 #endif 419 ifr.ifr_addr.sa_family = AF_UNSPEC; 420 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 421 RMP_ADDRLEN); 422 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 423 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 424 425 (void) close(BpfFd); 426 BpfFd = -1; 427 } 428