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