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 * from: @(#)bpf.c 8.1 (Berkeley) 6/4/93 42 * $Id: bpf.c,v 1.2 1994/01/11 16:41:23 brezak Exp $ 43 * 44 * From: 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 static char rcsid[] = "$Id: bpf.c,v 1.2 1994/01/11 16:41:23 brezak Exp $"; 51 #endif /* not lint */ 52 53 #include <sys/param.h> 54 #include <sys/ioctl.h> 55 #include <sys/socket.h> 56 57 #include <net/if.h> 58 #include <net/bpf.h> 59 60 #include <ctype.h> 61 #include <errno.h> 62 #include <fcntl.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <syslog.h> 67 #include <unistd.h> 68 #include "defs.h" 69 #include "pathnames.h" 70 71 static int BpfFd = -1; 72 static unsigned BpfLen = 0; 73 static u_char *BpfPkt = NULL; 74 75 /* 76 ** BpfOpen -- Open and initialize a BPF device. 77 ** 78 ** Parameters: 79 ** None. 80 ** 81 ** Returns: 82 ** File descriptor of opened BPF device (for select() etc). 83 ** 84 ** Side Effects: 85 ** If an error is encountered, the program terminates here. 86 */ 87 int 88 BpfOpen() 89 { 90 struct ifreq ifr; 91 char bpfdev[32]; 92 int n = 0; 93 94 /* 95 * Open the first available BPF device. 96 */ 97 do { 98 (void) sprintf(bpfdev, _PATH_BPF, n++); 99 BpfFd = open(bpfdev, O_RDWR); 100 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 101 102 if (BpfFd < 0) { 103 syslog(LOG_ERR, "bpf: no available devices: %m"); 104 Exit(0); 105 } 106 107 /* 108 * Set interface name for bpf device, get data link layer 109 * type and make sure it's type Ethernet. 110 */ 111 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 112 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 113 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 114 Exit(0); 115 } 116 117 /* 118 * Make sure we are dealing with an Ethernet device. 119 */ 120 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 121 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 122 Exit(0); 123 } 124 if (n != DLT_EN10MB) { 125 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 126 IntfName, n); 127 Exit(0); 128 } 129 130 /* 131 * On read(), return packets immediately (do not buffer them). 132 */ 133 n = 1; 134 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 135 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 136 Exit(0); 137 } 138 139 /* 140 * Try to enable the chip/driver's multicast address filter to 141 * grab our RMP address. If this fails, try promiscuous mode. 142 * If this fails, there's no way we are going to get any RMP 143 * packets so just exit here. 144 */ 145 #ifdef MSG_EOR 146 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 147 #endif 148 ifr.ifr_addr.sa_family = AF_UNSPEC; 149 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 150 if (ioctl(BpfFd, SIOCADDMULTI, (caddr_t)&ifr) < 0) { 151 syslog(LOG_WARNING, 152 "bpf: can't add mcast addr (%m), setting promiscuous mode"); 153 154 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 155 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 156 Exit(0); 157 } 158 } 159 160 /* 161 * Ask BPF how much buffer space it requires and allocate one. 162 */ 163 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 164 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 165 Exit(0); 166 } 167 if (BpfPkt == NULL) 168 BpfPkt = (u_char *)malloc(BpfLen); 169 170 if (BpfPkt == NULL) { 171 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 172 BpfLen); 173 Exit(0); 174 } 175 176 /* 177 * Write a little program to snarf RMP Boot packets and stuff 178 * it down BPF's throat (i.e. set up the packet filter). 179 */ 180 { 181 #define RMP ((struct rmp_packet *)0) 182 static struct bpf_insn bpf_insn[] = { 183 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 184 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 185 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 186 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 187 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 188 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 189 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 190 { BPF_RET|BPF_K, 0, 0, 0x0 } 191 }; 192 #undef RMP 193 static struct bpf_program bpf_pgm = { 194 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 195 }; 196 197 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 198 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 199 Exit(0); 200 } 201 } 202 203 return(BpfFd); 204 } 205 206 /* 207 ** BPF GetIntfName -- Return the name of a network interface attached to 208 ** the system, or 0 if none can be found. The interface 209 ** must be configured up; the lowest unit number is 210 ** preferred; loopback is ignored. 211 ** 212 ** Parameters: 213 ** errmsg - if no network interface found, *errmsg explains why. 214 ** 215 ** Returns: 216 ** A (static) pointer to interface name, or NULL on error. 217 ** 218 ** Side Effects: 219 ** None. 220 */ 221 char * 222 BpfGetIntfName(errmsg) 223 char **errmsg; 224 { 225 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 226 struct ifconf ifc; 227 int fd; 228 int minunit, n; 229 char *cp; 230 static char device[sizeof(ifrp->ifr_name)]; 231 static char errbuf[128] = "No Error!"; 232 233 if (errmsg != NULL) 234 *errmsg = errbuf; 235 236 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 237 (void) strcpy(errbuf, "bpf: socket: %m"); 238 return(NULL); 239 } 240 ifc.ifc_len = sizeof ibuf; 241 ifc.ifc_buf = (caddr_t)ibuf; 242 243 #ifdef OSIOCGIFCONF 244 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 245 ifc.ifc_len < sizeof(struct ifreq)) { 246 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 247 return(NULL); 248 } 249 #else 250 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 251 ifc.ifc_len < sizeof(struct ifreq)) { 252 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 253 return(NULL); 254 } 255 #endif 256 ifrp = ibuf; 257 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 258 259 mp = 0; 260 minunit = 666; 261 for (; ifrp < ifend; ++ifrp) { 262 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 263 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 264 return(NULL); 265 } 266 267 /* 268 * If interface is down or this is the loopback interface, 269 * ignore it. 270 */ 271 if ((ifrp->ifr_flags & IFF_UP) == 0 || 272 #ifdef IFF_LOOPBACK 273 (ifrp->ifr_flags & IFF_LOOPBACK)) 274 #else 275 (strcmp(ifrp->ifr_name, "lo0") == 0)) 276 #endif 277 continue; 278 279 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 280 ; 281 n = atoi(cp); 282 if (n < minunit) { 283 minunit = n; 284 mp = ifrp; 285 } 286 } 287 288 (void) close(fd); 289 if (mp == 0) { 290 (void) strcpy(errbuf, "bpf: no interfaces found"); 291 return(NULL); 292 } 293 294 (void) strcpy(device, mp->ifr_name); 295 return(device); 296 } 297 298 /* 299 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 300 ** 301 ** Parameters: 302 ** rconn - filled in with next packet. 303 ** doread - is True if we can issue a read() syscall. 304 ** 305 ** Returns: 306 ** True if `rconn' contains a new packet, False otherwise. 307 ** 308 ** Side Effects: 309 ** None. 310 */ 311 int 312 BpfRead(rconn, doread) 313 RMPCONN *rconn; 314 int doread; 315 { 316 register int datlen, caplen, hdrlen; 317 static u_char *bp = NULL, *ep = NULL; 318 int cc; 319 320 /* 321 * The read() may block, or it may return one or more packets. 322 * We let the caller decide whether or not we can issue a read(). 323 */ 324 if (doread) { 325 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 326 syslog(LOG_ERR, "bpf: read: %m"); 327 return(0); 328 } else { 329 bp = BpfPkt; 330 ep = BpfPkt + cc; 331 } 332 } 333 334 #define bhp ((struct bpf_hdr *)bp) 335 /* 336 * If there is a new packet in the buffer, stuff it into `rconn' 337 * and return a success indication. 338 */ 339 if (bp < ep) { 340 datlen = bhp->bh_datalen; 341 caplen = bhp->bh_caplen; 342 hdrlen = bhp->bh_hdrlen; 343 344 if (caplen != datlen) 345 syslog(LOG_ERR, 346 "bpf: short packet dropped (%d of %d bytes)", 347 caplen, datlen); 348 else if (caplen > sizeof(struct rmp_packet)) 349 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 350 caplen); 351 else { 352 rconn->rmplen = caplen; 353 bcopy((char *)&bhp->bh_tstamp, (char *)&rconn->tstamp, 354 sizeof(struct timeval)); 355 bcopy((char *)bp + hdrlen, (char *)&rconn->rmp, caplen); 356 } 357 bp += BPF_WORDALIGN(caplen + hdrlen); 358 return(1); 359 } 360 #undef bhp 361 362 return(0); 363 } 364 365 /* 366 ** BpfWrite -- Write packet to BPF device. 367 ** 368 ** Parameters: 369 ** rconn - packet to send. 370 ** 371 ** Returns: 372 ** True if write succeeded, False otherwise. 373 ** 374 ** Side Effects: 375 ** None. 376 */ 377 int 378 BpfWrite(rconn) 379 RMPCONN *rconn; 380 { 381 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 382 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 383 return(0); 384 } 385 386 return(1); 387 } 388 389 /* 390 ** BpfClose -- Close a BPF device. 391 ** 392 ** Parameters: 393 ** None. 394 ** 395 ** Returns: 396 ** Nothing. 397 ** 398 ** Side Effects: 399 ** None. 400 */ 401 void 402 BpfClose() 403 { 404 struct ifreq ifr; 405 406 if (BpfPkt != NULL) { 407 free((char *)BpfPkt); 408 BpfPkt = NULL; 409 } 410 411 if (BpfFd == -1) 412 return; 413 414 #ifdef MSG_EOR 415 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 416 #endif 417 ifr.ifr_addr.sa_family = AF_UNSPEC; 418 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 419 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 420 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 421 422 (void) close(BpfFd); 423 BpfFd = -1; 424 } 425