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 * @(#)bpf.c 8.1 (Berkeley) 6/4/93 47 * $FreeBSD: src/libexec/rbootd/bpf.c,v 1.10 1999/08/28 00:09:44 peter Exp $ 48 * $DragonFly: src/libexec/rbootd/bpf.c,v 1.2 2003/06/17 04:27:07 dillon Exp $ 49 */ 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() 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(errmsg) 217 char **errmsg; 218 { 219 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 220 struct ifconf ifc; 221 int fd; 222 int minunit, n; 223 char *cp; 224 static char device[sizeof(ifrp->ifr_name)]; 225 static char errbuf[128] = "No Error!"; 226 227 if (errmsg != NULL) 228 *errmsg = errbuf; 229 230 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 231 (void) strcpy(errbuf, "bpf: socket: %m"); 232 return(NULL); 233 } 234 ifc.ifc_len = sizeof ibuf; 235 ifc.ifc_buf = (caddr_t)ibuf; 236 237 #ifdef OSIOCGIFCONF 238 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 239 ifc.ifc_len < sizeof(struct ifreq)) { 240 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 241 return(NULL); 242 } 243 #else 244 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 245 ifc.ifc_len < sizeof(struct ifreq)) { 246 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 247 return(NULL); 248 } 249 #endif 250 ifrp = ibuf; 251 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 252 253 mp = 0; 254 minunit = 666; 255 for (; ifrp < ifend; ++ifrp) { 256 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 257 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 258 return(NULL); 259 } 260 261 /* 262 * If interface is down or this is the loopback interface, 263 * ignore it. 264 */ 265 if ((ifrp->ifr_flags & IFF_UP) == 0 || 266 #ifdef IFF_LOOPBACK 267 (ifrp->ifr_flags & IFF_LOOPBACK)) 268 #else 269 (strcmp(ifrp->ifr_name, "lo0") == 0)) 270 #endif 271 continue; 272 273 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 274 ; 275 n = atoi(cp); 276 if (n < minunit) { 277 minunit = n; 278 mp = ifrp; 279 } 280 } 281 282 (void) close(fd); 283 if (mp == 0) { 284 (void) strcpy(errbuf, "bpf: no interfaces found"); 285 return(NULL); 286 } 287 288 (void) strcpy(device, mp->ifr_name); 289 return(device); 290 } 291 292 /* 293 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 294 ** 295 ** Parameters: 296 ** rconn - filled in with next packet. 297 ** doread - is True if we can issue a read() syscall. 298 ** 299 ** Returns: 300 ** True if `rconn' contains a new packet, False otherwise. 301 ** 302 ** Side Effects: 303 ** None. 304 */ 305 int 306 BpfRead(rconn, doread) 307 RMPCONN *rconn; 308 int doread; 309 { 310 int datlen, caplen, hdrlen; 311 static u_int8_t *bp = NULL, *ep = NULL; 312 int cc; 313 314 /* 315 * The read() may block, or it may return one or more packets. 316 * We let the caller decide whether or not we can issue a read(). 317 */ 318 if (doread) { 319 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 320 syslog(LOG_ERR, "bpf: read: %m"); 321 return(0); 322 } else { 323 bp = BpfPkt; 324 ep = BpfPkt + cc; 325 } 326 } 327 328 #define bhp ((struct bpf_hdr *)bp) 329 /* 330 * If there is a new packet in the buffer, stuff it into `rconn' 331 * and return a success indication. 332 */ 333 if (bp < ep) { 334 datlen = bhp->bh_datalen; 335 caplen = bhp->bh_caplen; 336 hdrlen = bhp->bh_hdrlen; 337 338 if (caplen != datlen) 339 syslog(LOG_ERR, 340 "bpf: short packet dropped (%d of %d bytes)", 341 caplen, datlen); 342 else if (caplen > sizeof(struct rmp_packet)) 343 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 344 caplen); 345 else { 346 rconn->rmplen = caplen; 347 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 348 sizeof(struct timeval)); 349 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 350 } 351 bp += BPF_WORDALIGN(caplen + hdrlen); 352 return(1); 353 } 354 #undef bhp 355 356 return(0); 357 } 358 359 /* 360 ** BpfWrite -- Write packet to BPF device. 361 ** 362 ** Parameters: 363 ** rconn - packet to send. 364 ** 365 ** Returns: 366 ** True if write succeeded, False otherwise. 367 ** 368 ** Side Effects: 369 ** None. 370 */ 371 int 372 BpfWrite(rconn) 373 RMPCONN *rconn; 374 { 375 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 376 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 377 return(0); 378 } 379 380 return(1); 381 } 382 383 /* 384 ** BpfClose -- Close a BPF device. 385 ** 386 ** Parameters: 387 ** None. 388 ** 389 ** Returns: 390 ** Nothing. 391 ** 392 ** Side Effects: 393 ** None. 394 */ 395 void 396 BpfClose() 397 { 398 struct ifreq ifr; 399 400 if (BpfPkt != NULL) { 401 free((char *)BpfPkt); 402 BpfPkt = NULL; 403 } 404 405 if (BpfFd == -1) 406 return; 407 408 #ifdef MSG_EOR 409 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 410 #endif 411 ifr.ifr_addr.sa_family = AF_UNSPEC; 412 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 413 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 414 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 415 416 (void) close(BpfFd); 417 BpfFd = -1; 418 } 419