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 */ 49 50 #include <sys/param.h> 51 #include <sys/ioctl.h> 52 #include <sys/socket.h> 53 #include <sys/time.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_int8_t *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(void) 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 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 148 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 149 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 150 Exit(0); 151 } 152 153 /* 154 * Ask BPF how much buffer space it requires and allocate one. 155 */ 156 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 157 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 158 Exit(0); 159 } 160 if (BpfPkt == NULL) 161 BpfPkt = (u_int8_t *)malloc(BpfLen); 162 163 if (BpfPkt == NULL) { 164 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 165 BpfLen); 166 Exit(0); 167 } 168 169 /* 170 * Write a little program to snarf RMP Boot packets and stuff 171 * it down BPF's throat (i.e. set up the packet filter). 172 */ 173 { 174 #define RMP ((struct rmp_packet *)0) 175 static struct bpf_insn bpf_insn[] = { 176 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 177 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 178 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 179 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 180 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 181 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 182 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 183 { BPF_RET|BPF_K, 0, 0, 0x0 } 184 }; 185 #undef RMP 186 static struct bpf_program bpf_pgm = { 187 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 188 }; 189 190 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 191 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 192 Exit(0); 193 } 194 } 195 196 return(BpfFd); 197 } 198 199 /* 200 ** BPF GetIntfName -- Return the name of a network interface attached to 201 ** the system, or 0 if none can be found. The interface 202 ** must be configured up; the lowest unit number is 203 ** preferred; loopback is ignored. 204 ** 205 ** Parameters: 206 ** errmsg - if no network interface found, *errmsg explains why. 207 ** 208 ** Returns: 209 ** A (static) pointer to interface name, or NULL on error. 210 ** 211 ** Side Effects: 212 ** None. 213 */ 214 char * 215 BpfGetIntfName(char **errmsg) 216 { 217 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 218 struct ifconf ifc; 219 int fd; 220 int minunit, n; 221 char *cp; 222 static char device[sizeof(ifrp->ifr_name)]; 223 static char errbuf[128] = "No Error!"; 224 225 if (errmsg != NULL) 226 *errmsg = errbuf; 227 228 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 229 (void) strcpy(errbuf, "bpf: socket: %m"); 230 return(NULL); 231 } 232 ifc.ifc_len = sizeof ibuf; 233 ifc.ifc_buf = (caddr_t)ibuf; 234 235 #ifdef OSIOCGIFCONF 236 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 237 ifc.ifc_len < sizeof(struct ifreq)) { 238 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 239 return(NULL); 240 } 241 #else 242 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 243 ifc.ifc_len < sizeof(struct ifreq)) { 244 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 245 return(NULL); 246 } 247 #endif 248 ifrp = ibuf; 249 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 250 251 mp = NULL; 252 minunit = 666; 253 for (; ifrp < ifend; ++ifrp) { 254 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 255 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 256 return(NULL); 257 } 258 259 /* 260 * If interface is down or this is the loopback interface, 261 * ignore it. 262 */ 263 if ((ifrp->ifr_flags & IFF_UP) == 0 || 264 #ifdef IFF_LOOPBACK 265 (ifrp->ifr_flags & IFF_LOOPBACK)) 266 #else 267 (strcmp(ifrp->ifr_name, "lo0") == 0)) 268 #endif 269 continue; 270 271 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 272 ; 273 n = atoi(cp); 274 if (n < minunit) { 275 minunit = n; 276 mp = ifrp; 277 } 278 } 279 280 (void) close(fd); 281 if (mp == NULL) { 282 (void) strcpy(errbuf, "bpf: no interfaces found"); 283 return(NULL); 284 } 285 286 (void) strcpy(device, mp->ifr_name); 287 return(device); 288 } 289 290 /* 291 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 292 ** 293 ** Parameters: 294 ** rconn - filled in with next packet. 295 ** doread - is True if we can issue a read() syscall. 296 ** 297 ** Returns: 298 ** True if `rconn' contains a new packet, False otherwise. 299 ** 300 ** Side Effects: 301 ** None. 302 */ 303 int 304 BpfRead(RMPCONN *rconn, int doread) 305 { 306 int datlen, caplen, hdrlen; 307 static u_int8_t *bp = NULL, *ep = NULL; 308 int cc; 309 310 /* 311 * The read() may block, or it may return one or more packets. 312 * We let the caller decide whether or not we can issue a read(). 313 */ 314 if (doread) { 315 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 316 syslog(LOG_ERR, "bpf: read: %m"); 317 return(0); 318 } else { 319 bp = BpfPkt; 320 ep = BpfPkt + cc; 321 } 322 } 323 324 #define bhp ((struct bpf_hdr *)bp) 325 /* 326 * If there is a new packet in the buffer, stuff it into `rconn' 327 * and return a success indication. 328 */ 329 if (bp < ep) { 330 datlen = bhp->bh_datalen; 331 caplen = bhp->bh_caplen; 332 hdrlen = bhp->bh_hdrlen; 333 334 if (caplen != datlen) 335 syslog(LOG_ERR, 336 "bpf: short packet dropped (%d of %d bytes)", 337 caplen, datlen); 338 else if (caplen > sizeof(struct rmp_packet)) 339 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 340 caplen); 341 else { 342 rconn->rmplen = caplen; 343 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 344 sizeof(struct timeval)); 345 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 346 } 347 bp += BPF_WORDALIGN(caplen + hdrlen); 348 return(1); 349 } 350 #undef bhp 351 352 return(0); 353 } 354 355 /* 356 ** BpfWrite -- Write packet to BPF device. 357 ** 358 ** Parameters: 359 ** rconn - packet to send. 360 ** 361 ** Returns: 362 ** True if write succeeded, False otherwise. 363 ** 364 ** Side Effects: 365 ** None. 366 */ 367 int 368 BpfWrite(RMPCONN *rconn) 369 { 370 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 371 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 372 return(0); 373 } 374 375 return(1); 376 } 377 378 /* 379 ** BpfClose -- Close a BPF device. 380 ** 381 ** Parameters: 382 ** None. 383 ** 384 ** Returns: 385 ** Nothing. 386 ** 387 ** Side Effects: 388 ** None. 389 */ 390 void 391 BpfClose(void) 392 { 393 struct ifreq ifr; 394 395 if (BpfPkt != NULL) { 396 free((char *)BpfPkt); 397 BpfPkt = NULL; 398 } 399 400 if (BpfFd == -1) 401 return; 402 403 #ifdef MSG_EOR 404 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 405 #endif 406 ifr.ifr_addr.sa_family = AF_UNSPEC; 407 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 408 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 409 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 410 411 (void) close(BpfFd); 412 BpfFd = -1; 413 } 414