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 * 43 * Utah $Hdr: bpf.c 3.1 92/07/06$ 44 * Author: Jeff Forys, University of Utah CSS 45 */ 46 47 #ifndef lint 48 static char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93"; 49 #endif /* not lint */ 50 51 #include <sys/param.h> 52 #include <sys/ioctl.h> 53 #include <sys/socket.h> 54 55 #include <net/if.h> 56 #include <net/bpf.h> 57 58 #include <ctype.h> 59 #include <errno.h> 60 #include <fcntl.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <syslog.h> 65 #include <unistd.h> 66 #include "defs.h" 67 #include "pathnames.h" 68 69 static int BpfFd = -1; 70 static unsigned BpfLen = 0; 71 static u_char *BpfPkt = NULL; 72 73 /* 74 ** BpfOpen -- Open and initialize a BPF device. 75 ** 76 ** Parameters: 77 ** None. 78 ** 79 ** Returns: 80 ** File descriptor of opened BPF device (for select() etc). 81 ** 82 ** Side Effects: 83 ** If an error is encountered, the program terminates here. 84 */ 85 int 86 BpfOpen() 87 { 88 struct ifreq ifr; 89 char bpfdev[32]; 90 int n = 0; 91 92 /* 93 * Open the first available BPF device. 94 */ 95 do { 96 (void) sprintf(bpfdev, _PATH_BPF, n++); 97 BpfFd = open(bpfdev, O_RDWR); 98 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 99 100 if (BpfFd < 0) { 101 syslog(LOG_ERR, "bpf: no available devices: %m"); 102 Exit(0); 103 } 104 105 /* 106 * Set interface name for bpf device, get data link layer 107 * type and make sure it's type Ethernet. 108 */ 109 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 110 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 111 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 112 Exit(0); 113 } 114 115 /* 116 * Make sure we are dealing with an Ethernet device. 117 */ 118 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 119 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 120 Exit(0); 121 } 122 if (n != DLT_EN10MB) { 123 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 124 IntfName, n); 125 Exit(0); 126 } 127 128 /* 129 * On read(), return packets immediately (do not buffer them). 130 */ 131 n = 1; 132 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 133 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 134 Exit(0); 135 } 136 137 /* 138 * Try to enable the chip/driver's multicast address filter to 139 * grab our RMP address. If this fails, try promiscuous mode. 140 * If this fails, there's no way we are going to get any RMP 141 * packets so just exit here. 142 */ 143 #ifdef MSG_EOR 144 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 145 #endif 146 ifr.ifr_addr.sa_family = AF_UNSPEC; 147 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 148 if (ioctl(BpfFd, SIOCADDMULTI, (caddr_t)&ifr) < 0) { 149 syslog(LOG_WARNING, 150 "bpf: can't add mcast addr (%m), setting promiscuous mode"); 151 152 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 153 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 154 Exit(0); 155 } 156 } 157 158 /* 159 * Ask BPF how much buffer space it requires and allocate one. 160 */ 161 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 162 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 163 Exit(0); 164 } 165 if (BpfPkt == NULL) 166 BpfPkt = (u_char *)malloc(BpfLen); 167 168 if (BpfPkt == NULL) { 169 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 170 BpfLen); 171 Exit(0); 172 } 173 174 /* 175 * Write a little program to snarf RMP Boot packets and stuff 176 * it down BPF's throat (i.e. set up the packet filter). 177 */ 178 { 179 #define RMP ((struct rmp_packet *)0) 180 static struct bpf_insn bpf_insn[] = { 181 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 182 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 183 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 184 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 185 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 186 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 187 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 188 { BPF_RET|BPF_K, 0, 0, 0x0 } 189 }; 190 #undef RMP 191 static struct bpf_program bpf_pgm = { 192 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 193 }; 194 195 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 196 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 197 Exit(0); 198 } 199 } 200 201 return(BpfFd); 202 } 203 204 /* 205 ** BPF GetIntfName -- Return the name of a network interface attached to 206 ** the system, or 0 if none can be found. The interface 207 ** must be configured up; the lowest unit number is 208 ** preferred; loopback is ignored. 209 ** 210 ** Parameters: 211 ** errmsg - if no network interface found, *errmsg explains why. 212 ** 213 ** Returns: 214 ** A (static) pointer to interface name, or NULL on error. 215 ** 216 ** Side Effects: 217 ** None. 218 */ 219 char * 220 BpfGetIntfName(errmsg) 221 char **errmsg; 222 { 223 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 224 struct ifconf ifc; 225 int fd; 226 int minunit, n; 227 char *cp; 228 static char device[sizeof(ifrp->ifr_name)]; 229 static char errbuf[128] = "No Error!"; 230 231 if (errmsg != NULL) 232 *errmsg = errbuf; 233 234 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 235 (void) strcpy(errbuf, "bpf: socket: %m"); 236 return(NULL); 237 } 238 ifc.ifc_len = sizeof ibuf; 239 ifc.ifc_buf = (caddr_t)ibuf; 240 241 #ifdef OSIOCGIFCONF 242 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 243 ifc.ifc_len < sizeof(struct ifreq)) { 244 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 245 return(NULL); 246 } 247 #else 248 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 249 ifc.ifc_len < sizeof(struct ifreq)) { 250 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 251 return(NULL); 252 } 253 #endif 254 ifrp = ibuf; 255 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 256 257 mp = 0; 258 minunit = 666; 259 for (; ifrp < ifend; ++ifrp) { 260 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 261 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 262 return(NULL); 263 } 264 265 /* 266 * If interface is down or this is the loopback interface, 267 * ignore it. 268 */ 269 if ((ifrp->ifr_flags & IFF_UP) == 0 || 270 #ifdef IFF_LOOPBACK 271 (ifrp->ifr_flags & IFF_LOOPBACK)) 272 #else 273 (strcmp(ifrp->ifr_name, "lo0") == 0)) 274 #endif 275 continue; 276 277 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 278 ; 279 n = atoi(cp); 280 if (n < minunit) { 281 minunit = n; 282 mp = ifrp; 283 } 284 } 285 286 (void) close(fd); 287 if (mp == 0) { 288 (void) strcpy(errbuf, "bpf: no interfaces found"); 289 return(NULL); 290 } 291 292 (void) strcpy(device, mp->ifr_name); 293 return(device); 294 } 295 296 /* 297 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 298 ** 299 ** Parameters: 300 ** rconn - filled in with next packet. 301 ** doread - is True if we can issue a read() syscall. 302 ** 303 ** Returns: 304 ** True if `rconn' contains a new packet, False otherwise. 305 ** 306 ** Side Effects: 307 ** None. 308 */ 309 int 310 BpfRead(rconn, doread) 311 RMPCONN *rconn; 312 int doread; 313 { 314 register int datlen, caplen, hdrlen; 315 static u_char *bp = NULL, *ep = NULL; 316 int cc; 317 318 /* 319 * The read() may block, or it may return one or more packets. 320 * We let the caller decide whether or not we can issue a read(). 321 */ 322 if (doread) { 323 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 324 syslog(LOG_ERR, "bpf: read: %m"); 325 return(0); 326 } else { 327 bp = BpfPkt; 328 ep = BpfPkt + cc; 329 } 330 } 331 332 #define bhp ((struct bpf_hdr *)bp) 333 /* 334 * If there is a new packet in the buffer, stuff it into `rconn' 335 * and return a success indication. 336 */ 337 if (bp < ep) { 338 datlen = bhp->bh_datalen; 339 caplen = bhp->bh_caplen; 340 hdrlen = bhp->bh_hdrlen; 341 342 if (caplen != datlen) 343 syslog(LOG_ERR, 344 "bpf: short packet dropped (%d of %d bytes)", 345 caplen, datlen); 346 else if (caplen > sizeof(struct rmp_packet)) 347 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 348 caplen); 349 else { 350 rconn->rmplen = caplen; 351 bcopy((char *)&bhp->bh_tstamp, (char *)&rconn->tstamp, 352 sizeof(struct timeval)); 353 bcopy((char *)bp + hdrlen, (char *)&rconn->rmp, caplen); 354 } 355 bp += BPF_WORDALIGN(caplen + hdrlen); 356 return(1); 357 } 358 #undef bhp 359 360 return(0); 361 } 362 363 /* 364 ** BpfWrite -- Write packet to BPF device. 365 ** 366 ** Parameters: 367 ** rconn - packet to send. 368 ** 369 ** Returns: 370 ** True if write succeeded, False otherwise. 371 ** 372 ** Side Effects: 373 ** None. 374 */ 375 int 376 BpfWrite(rconn) 377 RMPCONN *rconn; 378 { 379 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 380 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 381 return(0); 382 } 383 384 return(1); 385 } 386 387 /* 388 ** BpfClose -- Close a BPF device. 389 ** 390 ** Parameters: 391 ** None. 392 ** 393 ** Returns: 394 ** Nothing. 395 ** 396 ** Side Effects: 397 ** None. 398 */ 399 void 400 BpfClose() 401 { 402 struct ifreq ifr; 403 404 if (BpfPkt != NULL) { 405 free((char *)BpfPkt); 406 BpfPkt = NULL; 407 } 408 409 if (BpfFd == -1) 410 return; 411 412 #ifdef MSG_EOR 413 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 414 #endif 415 ifr.ifr_addr.sa_family = AF_UNSPEC; 416 bcopy(&RmpMcastAddr[0], (char *)&ifr.ifr_addr.sa_data[0], RMP_ADDRLEN); 417 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 418 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 419 420 (void) close(BpfFd); 421 BpfFd = -1; 422 } 423