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 * @(#)bpf.c 8.1 (Berkeley) 6/4/93 43 * $FreeBSD: src/libexec/rbootd/bpf.c,v 1.10 1999/08/28 00:09:44 peter Exp $ 44 */ 45 46 #include <sys/param.h> 47 #include <sys/ioctl.h> 48 #include <sys/socket.h> 49 #include <sys/time.h> 50 51 #include <net/if.h> 52 #include <net/bpf.h> 53 54 #include <ctype.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <syslog.h> 61 #include <unistd.h> 62 #include "defs.h" 63 #include "pathnames.h" 64 65 static int BpfFd = -1; 66 static unsigned BpfLen = 0; 67 static u_int8_t *BpfPkt = NULL; 68 69 /* 70 ** BpfOpen -- Open and initialize a BPF device. 71 ** 72 ** Parameters: 73 ** None. 74 ** 75 ** Returns: 76 ** File descriptor of opened BPF device (for select() etc). 77 ** 78 ** Side Effects: 79 ** If an error is encountered, the program terminates here. 80 */ 81 int 82 BpfOpen(void) 83 { 84 struct ifreq ifr; 85 char bpfdev[32]; 86 int n = 0; 87 88 /* 89 * Open the first available BPF device. 90 */ 91 do { 92 (void) sprintf(bpfdev, _PATH_BPF, n++); 93 BpfFd = open(bpfdev, O_RDWR); 94 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 95 96 if (BpfFd < 0) { 97 syslog(LOG_ERR, "bpf: no available devices: %m"); 98 Exit(0); 99 } 100 101 /* 102 * Set interface name for bpf device, get data link layer 103 * type and make sure it's type Ethernet. 104 */ 105 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 106 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 107 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 108 Exit(0); 109 } 110 111 /* 112 * Make sure we are dealing with an Ethernet device. 113 */ 114 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 115 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 116 Exit(0); 117 } 118 if (n != DLT_EN10MB) { 119 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 120 IntfName, n); 121 Exit(0); 122 } 123 124 /* 125 * On read(), return packets immediately (do not buffer them). 126 */ 127 n = 1; 128 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 129 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 130 Exit(0); 131 } 132 133 /* 134 * Try to enable the chip/driver's multicast address filter to 135 * grab our RMP address. If this fails, try promiscuous mode. 136 * If this fails, there's no way we are going to get any RMP 137 * packets so just exit here. 138 */ 139 #ifdef MSG_EOR 140 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 141 #endif 142 ifr.ifr_addr.sa_family = AF_UNSPEC; 143 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 144 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 145 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 146 Exit(0); 147 } 148 149 /* 150 * Ask BPF how much buffer space it requires and allocate one. 151 */ 152 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 153 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 154 Exit(0); 155 } 156 if (BpfPkt == NULL) 157 BpfPkt = (u_int8_t *)malloc(BpfLen); 158 159 if (BpfPkt == NULL) { 160 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 161 BpfLen); 162 Exit(0); 163 } 164 165 /* 166 * Write a little program to snarf RMP Boot packets and stuff 167 * it down BPF's throat (i.e. set up the packet filter). 168 */ 169 { 170 #define RMP ((struct rmp_packet *)0) 171 static struct bpf_insn bpf_insn[] = { 172 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 173 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 174 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 175 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 176 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 177 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 178 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 179 { BPF_RET|BPF_K, 0, 0, 0x0 } 180 }; 181 #undef RMP 182 static struct bpf_program bpf_pgm = { 183 NELEM(bpf_insn), bpf_insn 184 }; 185 186 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 187 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 188 Exit(0); 189 } 190 } 191 192 return(BpfFd); 193 } 194 195 /* 196 ** BPF GetIntfName -- Return the name of a network interface attached to 197 ** the system, or 0 if none can be found. The interface 198 ** must be configured up; the lowest unit number is 199 ** preferred; loopback is ignored. 200 ** 201 ** Parameters: 202 ** errmsg - if no network interface found, *errmsg explains why. 203 ** 204 ** Returns: 205 ** A (static) pointer to interface name, or NULL on error. 206 ** 207 ** Side Effects: 208 ** None. 209 */ 210 char * 211 BpfGetIntfName(char **errmsg) 212 { 213 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 214 struct ifconf ifc; 215 int fd; 216 int minunit, n; 217 char *cp; 218 static char device[sizeof(ifrp->ifr_name)]; 219 static char errbuf[128] = "No Error!"; 220 221 if (errmsg != NULL) 222 *errmsg = errbuf; 223 224 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 225 (void) strcpy(errbuf, "bpf: socket: %m"); 226 return(NULL); 227 } 228 ifc.ifc_len = sizeof ibuf; 229 ifc.ifc_buf = (caddr_t)ibuf; 230 231 #ifdef OSIOCGIFCONF 232 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 || 233 ifc.ifc_len < sizeof(struct ifreq)) { 234 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m"); 235 return(NULL); 236 } 237 #else 238 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 239 ifc.ifc_len < sizeof(struct ifreq)) { 240 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 241 return(NULL); 242 } 243 #endif 244 ifrp = ibuf; 245 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 246 247 mp = NULL; 248 minunit = 666; 249 for (; ifrp < ifend; ++ifrp) { 250 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 251 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 252 return(NULL); 253 } 254 255 /* 256 * If interface is down or this is the loopback interface, 257 * ignore it. 258 */ 259 if ((ifrp->ifr_flags & IFF_UP) == 0 || 260 #ifdef IFF_LOOPBACK 261 (ifrp->ifr_flags & IFF_LOOPBACK)) 262 #else 263 (strcmp(ifrp->ifr_name, "lo0") == 0)) 264 #endif 265 continue; 266 267 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 268 ; 269 n = atoi(cp); 270 if (n < minunit) { 271 minunit = n; 272 mp = ifrp; 273 } 274 } 275 276 (void) close(fd); 277 if (mp == NULL) { 278 (void) strcpy(errbuf, "bpf: no interfaces found"); 279 return(NULL); 280 } 281 282 (void) strcpy(device, mp->ifr_name); 283 return(device); 284 } 285 286 /* 287 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 288 ** 289 ** Parameters: 290 ** rconn - filled in with next packet. 291 ** doread - is True if we can issue a read() syscall. 292 ** 293 ** Returns: 294 ** True if `rconn' contains a new packet, False otherwise. 295 ** 296 ** Side Effects: 297 ** None. 298 */ 299 int 300 BpfRead(RMPCONN *rconn, int doread) 301 { 302 int datlen, caplen, hdrlen; 303 static u_int8_t *bp = NULL, *ep = NULL; 304 int cc; 305 306 /* 307 * The read() may block, or it may return one or more packets. 308 * We let the caller decide whether or not we can issue a read(). 309 */ 310 if (doread) { 311 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 312 syslog(LOG_ERR, "bpf: read: %m"); 313 return(0); 314 } else { 315 bp = BpfPkt; 316 ep = BpfPkt + cc; 317 } 318 } 319 320 #define bhp ((struct bpf_hdr *)bp) 321 /* 322 * If there is a new packet in the buffer, stuff it into `rconn' 323 * and return a success indication. 324 */ 325 if (bp < ep) { 326 datlen = bhp->bh_datalen; 327 caplen = bhp->bh_caplen; 328 hdrlen = bhp->bh_hdrlen; 329 330 if (caplen != datlen) 331 syslog(LOG_ERR, 332 "bpf: short packet dropped (%d of %d bytes)", 333 caplen, datlen); 334 else if (caplen > sizeof(struct rmp_packet)) 335 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 336 caplen); 337 else { 338 rconn->rmplen = caplen; 339 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 340 sizeof(struct timeval)); 341 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 342 } 343 bp += BPF_WORDALIGN(caplen + hdrlen); 344 return(1); 345 } 346 #undef bhp 347 348 return(0); 349 } 350 351 /* 352 ** BpfWrite -- Write packet to BPF device. 353 ** 354 ** Parameters: 355 ** rconn - packet to send. 356 ** 357 ** Returns: 358 ** True if write succeeded, False otherwise. 359 ** 360 ** Side Effects: 361 ** None. 362 */ 363 int 364 BpfWrite(RMPCONN *rconn) 365 { 366 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 367 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 368 return(0); 369 } 370 371 return(1); 372 } 373 374 /* 375 ** BpfClose -- Close a BPF device. 376 ** 377 ** Parameters: 378 ** None. 379 ** 380 ** Returns: 381 ** Nothing. 382 ** 383 ** Side Effects: 384 ** None. 385 */ 386 void 387 BpfClose(void) 388 { 389 struct ifreq ifr; 390 391 if (BpfPkt != NULL) { 392 free((char *)BpfPkt); 393 BpfPkt = NULL; 394 } 395 396 if (BpfFd == -1) 397 return; 398 399 #ifdef MSG_EOR 400 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 401 #endif 402 ifr.ifr_addr.sa_family = AF_UNSPEC; 403 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 404 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 405 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 406 407 (void) close(BpfFd); 408 BpfFd = -1; 409 } 410