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. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)bpf.c 8.1 (Berkeley) 6/4/93 38 * 39 * From: Utah Hdr: bpf.c 3.1 92/07/06 40 * Author: Jeff Forys, University of Utah CSS 41 */ 42 43 #ifndef lint 44 #if 0 45 static const char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93"; 46 #endif 47 static const char rcsid[] = 48 "$FreeBSD$"; 49 #endif /* not lint */ 50 51 #include <sys/param.h> 52 #include <sys/ioctl.h> 53 #include <sys/socket.h> 54 #include <sys/time.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_int8_t *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(void) 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 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 149 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 150 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 151 Exit(0); 152 } 153 154 /* 155 * Ask BPF how much buffer space it requires and allocate one. 156 */ 157 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 158 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 159 Exit(0); 160 } 161 if (BpfPkt == NULL) 162 BpfPkt = (u_int8_t *)malloc(BpfLen); 163 164 if (BpfPkt == NULL) { 165 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 166 BpfLen); 167 Exit(0); 168 } 169 170 /* 171 * Write a little program to snarf RMP Boot packets and stuff 172 * it down BPF's throat (i.e. set up the packet filter). 173 */ 174 { 175 #define RMP ((struct rmp_packet *)0) 176 static struct bpf_insn bpf_insn[] = { 177 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 178 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 179 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 180 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 181 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 182 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 183 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 184 { BPF_RET|BPF_K, 0, 0, 0x0 } 185 }; 186 #undef RMP 187 static struct bpf_program bpf_pgm = { 188 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 189 }; 190 191 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 192 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 193 Exit(0); 194 } 195 } 196 197 return(BpfFd); 198 } 199 200 /* 201 ** BPF GetIntfName -- Return the name of a network interface attached to 202 ** the system, or 0 if none can be found. The interface 203 ** must be configured up; the lowest unit number is 204 ** preferred; loopback is ignored. 205 ** 206 ** Parameters: 207 ** errmsg - if no network interface found, *errmsg explains why. 208 ** 209 ** Returns: 210 ** A (static) pointer to interface name, or NULL on error. 211 ** 212 ** Side Effects: 213 ** None. 214 */ 215 char * 216 BpfGetIntfName(char **errmsg) 217 { 218 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 219 struct ifconf ifc; 220 int fd; 221 int minunit, n; 222 char *cp; 223 static char device[sizeof(ifrp->ifr_name)]; 224 static char errbuf[128] = "No Error!"; 225 226 if (errmsg != NULL) 227 *errmsg = errbuf; 228 229 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 230 (void) strcpy(errbuf, "bpf: socket: %m"); 231 return(NULL); 232 } 233 ifc.ifc_len = sizeof ibuf; 234 ifc.ifc_buf = (caddr_t)ibuf; 235 236 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 237 ifc.ifc_len < sizeof(struct ifreq)) { 238 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 239 return(NULL); 240 } 241 ifrp = ibuf; 242 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 243 244 mp = 0; 245 minunit = 666; 246 for (; ifrp < ifend; ++ifrp) { 247 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 248 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 249 return(NULL); 250 } 251 252 /* 253 * If interface is down or this is the loopback interface, 254 * ignore it. 255 */ 256 if ((ifrp->ifr_flags & IFF_UP) == 0 || 257 #ifdef IFF_LOOPBACK 258 (ifrp->ifr_flags & IFF_LOOPBACK)) 259 #else 260 (strcmp(ifrp->ifr_name, "lo0") == 0)) 261 #endif 262 continue; 263 264 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 265 ; 266 n = atoi(cp); 267 if (n < minunit) { 268 minunit = n; 269 mp = ifrp; 270 } 271 } 272 273 (void) close(fd); 274 if (mp == 0) { 275 (void) strcpy(errbuf, "bpf: no interfaces found"); 276 return(NULL); 277 } 278 279 (void) strcpy(device, mp->ifr_name); 280 return(device); 281 } 282 283 /* 284 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 285 ** 286 ** Parameters: 287 ** rconn - filled in with next packet. 288 ** doread - is True if we can issue a read() syscall. 289 ** 290 ** Returns: 291 ** True if `rconn' contains a new packet, False otherwise. 292 ** 293 ** Side Effects: 294 ** None. 295 */ 296 int 297 BpfRead(RMPCONN *rconn, int doread) 298 { 299 int datlen, caplen, hdrlen; 300 static u_int8_t *bp = NULL, *ep = NULL; 301 int cc; 302 303 /* 304 * The read() may block, or it may return one or more packets. 305 * We let the caller decide whether or not we can issue a read(). 306 */ 307 if (doread) { 308 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 309 syslog(LOG_ERR, "bpf: read: %m"); 310 return(0); 311 } else { 312 bp = BpfPkt; 313 ep = BpfPkt + cc; 314 } 315 } 316 317 #define bhp ((struct bpf_hdr *)bp) 318 /* 319 * If there is a new packet in the buffer, stuff it into `rconn' 320 * and return a success indication. 321 */ 322 if (bp < ep) { 323 datlen = bhp->bh_datalen; 324 caplen = bhp->bh_caplen; 325 hdrlen = bhp->bh_hdrlen; 326 327 if (caplen != datlen) 328 syslog(LOG_ERR, 329 "bpf: short packet dropped (%d of %d bytes)", 330 caplen, datlen); 331 else if (caplen > sizeof(struct rmp_packet)) 332 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 333 caplen); 334 else { 335 rconn->rmplen = caplen; 336 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 337 sizeof(struct timeval)); 338 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 339 } 340 bp += BPF_WORDALIGN(caplen + hdrlen); 341 return(1); 342 } 343 #undef bhp 344 345 return(0); 346 } 347 348 /* 349 ** BpfWrite -- Write packet to BPF device. 350 ** 351 ** Parameters: 352 ** rconn - packet to send. 353 ** 354 ** Returns: 355 ** True if write succeeded, False otherwise. 356 ** 357 ** Side Effects: 358 ** None. 359 */ 360 int 361 BpfWrite(RMPCONN *rconn) 362 { 363 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 364 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 365 return(0); 366 } 367 368 return(1); 369 } 370 371 /* 372 ** BpfClose -- Close a BPF device. 373 ** 374 ** Parameters: 375 ** None. 376 ** 377 ** Returns: 378 ** Nothing. 379 ** 380 ** Side Effects: 381 ** None. 382 */ 383 void 384 BpfClose(void) 385 { 386 struct ifreq ifr; 387 388 if (BpfPkt != NULL) { 389 free((char *)BpfPkt); 390 BpfPkt = NULL; 391 } 392 393 if (BpfFd == -1) 394 return; 395 396 #ifdef MSG_EOR 397 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 398 #endif 399 ifr.ifr_addr.sa_family = AF_UNSPEC; 400 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 401 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 402 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 403 404 (void) close(BpfFd); 405 BpfFd = -1; 406 } 407