1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1988, 1992 The University of Utah and the Center 5 * for Software Science (CSS). 6 * Copyright (c) 1992, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * the Center for Software Science of the University of Utah Computer 11 * Science Department. CSS requests users of this software to return 12 * to css-dist@cs.utah.edu any improvements that they make and grant 13 * CSS redistribution rights. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * From: Utah Hdr: bpf.c 3.1 92/07/06 40 * Author: Jeff Forys, University of Utah CSS 41 */ 42 43 #include <sys/param.h> 44 #include <sys/ioctl.h> 45 #include <sys/socket.h> 46 #include <sys/time.h> 47 48 #include <net/if.h> 49 #include <net/bpf.h> 50 51 #include <ctype.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <syslog.h> 58 #include <unistd.h> 59 #include "defs.h" 60 #include "pathnames.h" 61 62 static int BpfFd = -1; 63 static unsigned BpfLen = 0; 64 static u_int8_t *BpfPkt = NULL; 65 66 /* 67 ** BpfOpen -- Open and initialize a BPF device. 68 ** 69 ** Parameters: 70 ** None. 71 ** 72 ** Returns: 73 ** File descriptor of opened BPF device (for select() etc). 74 ** 75 ** Side Effects: 76 ** If an error is encountered, the program terminates here. 77 */ 78 int 79 BpfOpen(void) 80 { 81 struct ifreq ifr; 82 char bpfdev[32]; 83 int n = 0; 84 85 /* 86 * Open the first available BPF device. 87 */ 88 do { 89 (void) sprintf(bpfdev, _PATH_BPF, n++); 90 BpfFd = open(bpfdev, O_RDWR); 91 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM)); 92 93 if (BpfFd < 0) { 94 syslog(LOG_ERR, "bpf: no available devices: %m"); 95 Exit(0); 96 } 97 98 /* 99 * Set interface name for bpf device, get data link layer 100 * type and make sure it's type Ethernet. 101 */ 102 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 103 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 104 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 105 Exit(0); 106 } 107 108 /* 109 * Make sure we are dealing with an Ethernet device. 110 */ 111 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 112 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 113 Exit(0); 114 } 115 if (n != DLT_EN10MB) { 116 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 117 IntfName, n); 118 Exit(0); 119 } 120 121 /* 122 * On read(), return packets immediately (do not buffer them). 123 */ 124 n = 1; 125 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 126 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 127 Exit(0); 128 } 129 130 /* 131 * Try to enable the chip/driver's multicast address filter to 132 * grab our RMP address. If this fails, try promiscuous mode. 133 * If this fails, there's no way we are going to get any RMP 134 * packets so just exit here. 135 */ 136 #ifdef MSG_EOR 137 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 138 #endif 139 ifr.ifr_addr.sa_family = AF_UNSPEC; 140 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 141 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 142 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 143 Exit(0); 144 } 145 146 /* 147 * Ask BPF how much buffer space it requires and allocate one. 148 */ 149 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 150 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 151 Exit(0); 152 } 153 if (BpfPkt == NULL) 154 BpfPkt = (u_int8_t *)malloc(BpfLen); 155 156 if (BpfPkt == NULL) { 157 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 158 BpfLen); 159 Exit(0); 160 } 161 162 /* 163 * Write a little program to snarf RMP Boot packets and stuff 164 * it down BPF's throat (i.e. set up the packet filter). 165 */ 166 { 167 #define RMP ((struct rmp_packet *)0) 168 static struct bpf_insn bpf_insn[] = { 169 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 170 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 171 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 172 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 173 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 174 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 175 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 176 { BPF_RET|BPF_K, 0, 0, 0x0 } 177 }; 178 #undef RMP 179 static struct bpf_program bpf_pgm = { 180 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 181 }; 182 183 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 184 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 185 Exit(0); 186 } 187 } 188 189 return(BpfFd); 190 } 191 192 /* 193 ** BPF GetIntfName -- Return the name of a network interface attached to 194 ** the system, or 0 if none can be found. The interface 195 ** must be configured up; the lowest unit number is 196 ** preferred; loopback is ignored. 197 ** 198 ** Parameters: 199 ** errmsg - if no network interface found, *errmsg explains why. 200 ** 201 ** Returns: 202 ** A (static) pointer to interface name, or NULL on error. 203 ** 204 ** Side Effects: 205 ** None. 206 */ 207 char * 208 BpfGetIntfName(char **errmsg) 209 { 210 struct ifreq ibuf[8], *ifrp, *ifend, *mp; 211 struct ifconf ifc; 212 int fd; 213 int minunit, n; 214 char *cp; 215 static char device[sizeof(ifrp->ifr_name)]; 216 static char errbuf[128] = "No Error!"; 217 218 if (errmsg != NULL) 219 *errmsg = errbuf; 220 221 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 222 (void) strcpy(errbuf, "bpf: socket: %m"); 223 return(NULL); 224 } 225 ifc.ifc_len = sizeof ibuf; 226 ifc.ifc_buf = (caddr_t)ibuf; 227 228 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 229 ifc.ifc_len < sizeof(struct ifreq)) { 230 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m"); 231 return(NULL); 232 } 233 ifrp = ibuf; 234 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 235 236 mp = NULL; 237 minunit = 666; 238 for (; ifrp < ifend; ++ifrp) { 239 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) { 240 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m"); 241 return(NULL); 242 } 243 244 /* 245 * If interface is down or this is the loopback interface, 246 * ignore it. 247 */ 248 if ((ifrp->ifr_flags & IFF_UP) == 0 || 249 #ifdef IFF_LOOPBACK 250 (ifrp->ifr_flags & IFF_LOOPBACK)) 251 #else 252 (strcmp(ifrp->ifr_name, "lo0") == 0)) 253 #endif 254 continue; 255 256 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 257 ; 258 n = atoi(cp); 259 if (n < minunit) { 260 minunit = n; 261 mp = ifrp; 262 } 263 } 264 265 (void) close(fd); 266 if (mp == NULL) { 267 (void) strcpy(errbuf, "bpf: no interfaces found"); 268 return(NULL); 269 } 270 271 (void) strcpy(device, mp->ifr_name); 272 return(device); 273 } 274 275 /* 276 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 277 ** 278 ** Parameters: 279 ** rconn - filled in with next packet. 280 ** doread - is True if we can issue a read() syscall. 281 ** 282 ** Returns: 283 ** True if `rconn' contains a new packet, False otherwise. 284 ** 285 ** Side Effects: 286 ** None. 287 */ 288 int 289 BpfRead(RMPCONN *rconn, int doread) 290 { 291 int datlen, caplen, hdrlen; 292 static u_int8_t *bp = NULL, *ep = NULL; 293 int cc; 294 295 /* 296 * The read() may block, or it may return one or more packets. 297 * We let the caller decide whether or not we can issue a read(). 298 */ 299 if (doread) { 300 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 301 syslog(LOG_ERR, "bpf: read: %m"); 302 return(0); 303 } else { 304 bp = BpfPkt; 305 ep = BpfPkt + cc; 306 } 307 } 308 309 #define bhp ((struct bpf_hdr *)bp) 310 /* 311 * If there is a new packet in the buffer, stuff it into `rconn' 312 * and return a success indication. 313 */ 314 if (bp < ep) { 315 datlen = bhp->bh_datalen; 316 caplen = bhp->bh_caplen; 317 hdrlen = bhp->bh_hdrlen; 318 319 if (caplen != datlen) 320 syslog(LOG_ERR, 321 "bpf: short packet dropped (%d of %d bytes)", 322 caplen, datlen); 323 else if (caplen > sizeof(struct rmp_packet)) 324 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 325 caplen); 326 else { 327 rconn->rmplen = caplen; 328 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 329 sizeof(struct timeval)); 330 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen); 331 } 332 bp += BPF_WORDALIGN(caplen + hdrlen); 333 return(1); 334 } 335 #undef bhp 336 337 return(0); 338 } 339 340 /* 341 ** BpfWrite -- Write packet to BPF device. 342 ** 343 ** Parameters: 344 ** rconn - packet to send. 345 ** 346 ** Returns: 347 ** True if write succeeded, False otherwise. 348 ** 349 ** Side Effects: 350 ** None. 351 */ 352 int 353 BpfWrite(RMPCONN *rconn) 354 { 355 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 356 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 357 return(0); 358 } 359 360 return(1); 361 } 362 363 /* 364 ** BpfClose -- Close a BPF device. 365 ** 366 ** Parameters: 367 ** None. 368 ** 369 ** Returns: 370 ** Nothing. 371 ** 372 ** Side Effects: 373 ** None. 374 */ 375 void 376 BpfClose(void) 377 { 378 struct ifreq ifr; 379 380 if (BpfPkt != NULL) { 381 free((char *)BpfPkt); 382 BpfPkt = NULL; 383 } 384 385 if (BpfFd == -1) 386 return; 387 388 #ifdef MSG_EOR 389 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 390 #endif 391 ifr.ifr_addr.sa_family = AF_UNSPEC; 392 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN); 393 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 394 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 395 396 (void) close(BpfFd); 397 BpfFd = -1; 398 } 399