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