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 * 43 * From: Utah Hdr: bpf.c 3.1 92/07/06 44 * Author: Jeff Forys, University of Utah CSS 45 */ 46 47 #ifndef lint 48 #if 0 49 static const char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93"; 50 #endif 51 static const char rcsid[] = 52 "$FreeBSD$"; 53 #endif /* not lint */ 54 55 #include <sys/param.h> 56 #include <sys/ioctl.h> 57 #include <sys/socket.h> 58 #include <sys/time.h> 59 60 #include <net/if.h> 61 #include <net/bpf.h> 62 63 #include <ctype.h> 64 #include <errno.h> 65 #include <fcntl.h> 66 #include <stdio.h> 67 #include <stdlib.h> 68 #include <string.h> 69 #include <syslog.h> 70 #include <unistd.h> 71 #include "defs.h" 72 #include "pathnames.h" 73 74 static int BpfFd = -1; 75 static unsigned BpfLen = 0; 76 static u_int8_t *BpfPkt = NULL; 77 78 /* 79 ** BpfOpen -- Open and initialize a BPF device. 80 ** 81 ** Parameters: 82 ** None. 83 ** 84 ** Returns: 85 ** File descriptor of opened BPF device (for select() etc). 86 ** 87 ** Side Effects: 88 ** If an error is encountered, the program terminates here. 89 */ 90 int 91 BpfOpen(void) 92 { 93 struct ifreq ifr; 94 char bpfdev[32]; 95 int n = 0; 96 97 /* 98 * Open the first available BPF device. 99 */ 100 do { 101 (void) sprintf(bpfdev, _PATH_BPF, n++); 102 BpfFd = open(bpfdev, O_RDWR); 103 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 104 105 if (BpfFd < 0) { 106 syslog(LOG_ERR, "bpf: no available devices: %m"); 107 Exit(0); 108 } 109 110 /* 111 * Set interface name for bpf device, get data link layer 112 * type and make sure it's type Ethernet. 113 */ 114 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 115 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 116 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 117 Exit(0); 118 } 119 120 /* 121 * Make sure we are dealing with an Ethernet device. 122 */ 123 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 124 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 125 Exit(0); 126 } 127 if (n != DLT_EN10MB) { 128 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 129 IntfName, n); 130 Exit(0); 131 } 132 133 /* 134 * On read(), return packets immediately (do not buffer them). 135 */ 136 n = 1; 137 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 138 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 139 Exit(0); 140 } 141 142 /* 143 * Try to enable the chip/driver's multicast address filter to 144 * grab our RMP address. If this fails, try promiscuous mode. 145 * If this fails, there's no way we are going to get any RMP 146 * packets so just exit here. 147 */ 148 #ifdef MSG_EOR 149 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 150 #endif 151 ifr.ifr_addr.sa_family = AF_UNSPEC; 152 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 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 * 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_int8_t *)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(char **errmsg) 221 { 222 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 223 struct ifconf ifc; 224 int fd; 225 int minunit, n; 226 char *cp; 227 static char device[sizeof(ifrp->ifr_name)]; 228 static char errbuf[128] = "No Error!"; 229 230 if (errmsg != NULL) 231 *errmsg = errbuf; 232 233 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 234 (void) strcpy(errbuf, "bpf: socket: %m"); 235 return(NULL); 236 } 237 ifc.ifc_len = sizeof ibuf; 238 ifc.ifc_buf = (caddr_t)ibuf; 239 240 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 241 ifc.ifc_len < sizeof(struct ifreq)) { 242 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 243 return(NULL); 244 } 245 ifrp = ibuf; 246 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 247 248 mp = 0; 249 minunit = 666; 250 for (; ifrp < ifend; ++ifrp) { 251 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 252 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 253 return(NULL); 254 } 255 256 /* 257 * If interface is down or this is the loopback interface, 258 * ignore it. 259 */ 260 if ((ifrp->ifr_flags & IFF_UP) == 0 || 261 #ifdef IFF_LOOPBACK 262 (ifrp->ifr_flags & IFF_LOOPBACK)) 263 #else 264 (strcmp(ifrp->ifr_name, "lo0") == 0)) 265 #endif 266 continue; 267 268 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 269 ; 270 n = atoi(cp); 271 if (n < minunit) { 272 minunit = n; 273 mp = ifrp; 274 } 275 } 276 277 (void) close(fd); 278 if (mp == 0) { 279 (void) strcpy(errbuf, "bpf: no interfaces found"); 280 return(NULL); 281 } 282 283 (void) strcpy(device, mp->ifr_name); 284 return(device); 285 } 286 287 /* 288 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 289 ** 290 ** Parameters: 291 ** rconn - filled in with next packet. 292 ** doread - is True if we can issue a read() syscall. 293 ** 294 ** Returns: 295 ** True if `rconn' contains a new packet, False otherwise. 296 ** 297 ** Side Effects: 298 ** None. 299 */ 300 int 301 BpfRead(RMPCONN *rconn, int doread) 302 { 303 int datlen, caplen, hdrlen; 304 static u_int8_t *bp = NULL, *ep = NULL; 305 int cc; 306 307 /* 308 * The read() may block, or it may return one or more packets. 309 * We let the caller decide whether or not we can issue a read(). 310 */ 311 if (doread) { 312 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 313 syslog(LOG_ERR, "bpf: read: %m"); 314 return(0); 315 } else { 316 bp = BpfPkt; 317 ep = BpfPkt + cc; 318 } 319 } 320 321 #define bhp ((struct bpf_hdr *)bp) 322 /* 323 * If there is a new packet in the buffer, stuff it into `rconn' 324 * and return a success indication. 325 */ 326 if (bp < ep) { 327 datlen = bhp->bh_datalen; 328 caplen = bhp->bh_caplen; 329 hdrlen = bhp->bh_hdrlen; 330 331 if (caplen != datlen) 332 syslog(LOG_ERR, 333 "bpf: short packet dropped (%d of %d bytes)", 334 caplen, datlen); 335 else if (caplen > sizeof(struct rmp_packet)) 336 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 337 caplen); 338 else { 339 rconn->rmplen = caplen; 340 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 341 sizeof(struct timeval)); 342 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 343 } 344 bp += BPF_WORDALIGN(caplen + hdrlen); 345 return(1); 346 } 347 #undef bhp 348 349 return(0); 350 } 351 352 /* 353 ** BpfWrite -- Write packet to BPF device. 354 ** 355 ** Parameters: 356 ** rconn - packet to send. 357 ** 358 ** Returns: 359 ** True if write succeeded, False otherwise. 360 ** 361 ** Side Effects: 362 ** None. 363 */ 364 int 365 BpfWrite(RMPCONN *rconn) 366 { 367 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 368 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 369 return(0); 370 } 371 372 return(1); 373 } 374 375 /* 376 ** BpfClose -- Close a BPF device. 377 ** 378 ** Parameters: 379 ** None. 380 ** 381 ** Returns: 382 ** Nothing. 383 ** 384 ** Side Effects: 385 ** None. 386 */ 387 void 388 BpfClose(void) 389 { 390 struct ifreq ifr; 391 392 if (BpfPkt != NULL) { 393 free((char *)BpfPkt); 394 BpfPkt = NULL; 395 } 396 397 if (BpfFd == -1) 398 return; 399 400 #ifdef MSG_EOR 401 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 402 #endif 403 ifr.ifr_addr.sa_family = AF_UNSPEC; 404 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 405 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 406 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 407 408 (void) close(BpfFd); 409 BpfFd = -1; 410 } 411