1 /* $NetBSD: bpf.c,v 1.22 2022/09/03 07:45:08 tsutsui Exp $ */ 2 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 (at) 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: @(#)bpf.c 8.1 (Berkeley) 6/4/93 40 * 41 * From: Utah Hdr: bpf.c 3.1 92/07/06 42 * Author: Jeff Forys, University of Utah CSS 43 */ 44 45 #include <sys/cdefs.h> 46 #ifndef lint 47 #if 0 48 static char sccsid[] = "@(#)bpf.c 8.1 (Berkeley) 6/4/93"; 49 #else 50 __RCSID("$NetBSD: bpf.c,v 1.22 2022/09/03 07:45:08 tsutsui Exp $"); 51 #endif 52 #endif /* not lint */ 53 54 #include <sys/param.h> 55 #include <sys/ioctl.h> 56 #include <sys/socket.h> 57 58 #include <net/if.h> 59 #include <net/bpf.h> 60 61 #include <ctype.h> 62 #include <errno.h> 63 #include <fcntl.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <paths.h> 69 #include <unistd.h> 70 #include <ifaddrs.h> 71 #include "defs.h" 72 #include "pathnames.h" 73 74 static int BpfFd = -1; 75 static unsigned BpfLen = 0; 76 static u_int8_t *BpfPkt = NULL; 77 78 /* 79 ** BpfOpen -- Open and initialize a BPF device. 80 ** 81 ** Parameters: 82 ** None. 83 ** 84 ** Returns: 85 ** File descriptor of opened BPF device (for select() etc). 86 ** 87 ** Side Effects: 88 ** If an error is encountered, the program terminates here. 89 */ 90 int 91 BpfOpen(void) 92 { 93 struct ifreq ifr; 94 u_int bufsize = 32768; 95 int n; 96 97 BpfFd = open(_PATH_BPF, O_RDWR); 98 if (BpfFd < 0) { 99 syslog(LOG_ERR, "bpf: no available devices: %m"); 100 Exit(0); 101 } 102 103 if (ioctl(BpfFd, BIOCSBLEN, &bufsize) < 0) { 104 syslog(LOG_ERR, "bpf: ioctl(BIOCSBLEN,%d): %m", bufsize); 105 } 106 107 /* 108 * Set interface name for bpf device, get data link layer 109 * type and make sure it's type Ethernet. 110 */ 111 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name)); 112 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) { 113 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName); 114 Exit(0); 115 } 116 117 /* 118 * Make sure we are dealing with an Ethernet device. 119 */ 120 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) { 121 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m"); 122 Exit(0); 123 } 124 if (n != DLT_EN10MB) { 125 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported", 126 IntfName, n); 127 Exit(0); 128 } 129 130 /* 131 * On read(), return packets immediately (do not buffer them). 132 */ 133 n = 1; 134 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) { 135 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m"); 136 Exit(0); 137 } 138 139 /* 140 * Try to enable the chip/driver's multicast address filter to 141 * grab our RMP address. If this fails, try promiscuous mode. 142 * If this fails, there's no way we are going to get any RMP 143 * packets so just exit here. 144 */ 145 #ifdef MSG_EOR 146 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 147 #endif 148 ifr.ifr_addr.sa_family = AF_UNSPEC; 149 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 150 RMP_ADDRLEN); 151 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) { 152 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m"); 153 Exit(0); 154 } 155 156 /* 157 * Ask BPF how much buffer space it requires and allocate one. 158 */ 159 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) { 160 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m"); 161 Exit(0); 162 } 163 if (BpfPkt == NULL) 164 BpfPkt = (u_int8_t *)malloc(BpfLen); 165 166 if (BpfPkt == NULL) { 167 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)", 168 BpfLen); 169 Exit(0); 170 } 171 172 /* 173 * Write a little program to snarf RMP Boot packets and stuff 174 * it down BPF's throat (i.e. set up the packet filter). 175 */ 176 { 177 #define RMP ((struct rmp_packet *)0) 178 static struct bpf_insn bpf_insn[] = { 179 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap }, 180 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP }, 181 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl }, 182 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP }, 183 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap }, 184 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP }, 185 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET }, 186 { BPF_RET|BPF_K, 0, 0, 0x0 } 187 }; 188 #undef RMP 189 static struct bpf_program bpf_pgm = { 190 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn 191 }; 192 193 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) { 194 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m"); 195 Exit(0); 196 } 197 } 198 199 return(BpfFd); 200 } 201 202 /* 203 ** BPF GetIntfName -- Return the name of a network interface attached to 204 ** the system, or 0 if none can be found. The interface 205 ** must be configured up; the lowest unit number is 206 ** preferred; loopback is ignored. 207 ** 208 ** Parameters: 209 ** errmsg - if no network interface found, *errmsg explains why. 210 ** 211 ** Returns: 212 ** A (static) pointer to interface name, or NULL on error. 213 ** 214 ** Side Effects: 215 ** None. 216 */ 217 char * 218 BpfGetIntfName(char **errmsg) 219 { 220 struct ifaddrs *ifap, *ifa, *p; 221 int minunit, n; 222 char *cp; 223 static char device[IFNAMSIZ + 1]; 224 static char errbuf[128] = "No Error!"; 225 226 if (errmsg != NULL) 227 *errmsg = errbuf; 228 229 if (getifaddrs(&ifap) != 0) { 230 (void) strlcpy(errbuf, "bpf: getifaddrs: %m", sizeof(errbuf)); 231 return(NULL); 232 } 233 234 p = NULL; 235 minunit = 666; 236 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 237 /* 238 * If interface is down or this is the loopback interface, 239 * ignore it. 240 */ 241 if ((ifa->ifa_flags & IFF_UP) == 0 || 242 #ifdef IFF_LOOPBACK 243 (ifa->ifa_flags & IFF_LOOPBACK)) 244 #else 245 (strcmp(ifa->ifa_name, "lo0") == 0)) 246 #endif 247 continue; 248 249 for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp) 250 ; 251 n = atoi(cp); 252 if (n < minunit) { 253 minunit = n; 254 p = ifa; 255 } 256 } 257 if (p == NULL) { 258 (void) strlcpy(errbuf, "bpf: no interfaces found", 259 sizeof(errbuf)); 260 freeifaddrs(ifap); 261 return(NULL); 262 } 263 264 (void) strlcpy(device, p->ifa_name, sizeof(device)); 265 freeifaddrs(ifap); 266 return(device); 267 } 268 269 /* 270 ** BpfRead -- Read packets from a BPF device and fill in `rconn'. 271 ** 272 ** Parameters: 273 ** rconn - filled in with next packet. 274 ** doread - is True if we can issue a read() syscall. 275 ** 276 ** Returns: 277 ** True if `rconn' contains a new packet, False otherwise. 278 ** 279 ** Side Effects: 280 ** None. 281 */ 282 int 283 BpfRead(RMPCONN *rconn, int doread) 284 { 285 int datlen, caplen, hdrlen; 286 static u_int8_t *bp = NULL, *ep = NULL; 287 int cc; 288 289 /* 290 * The read() may block, or it may return one or more packets. 291 * We let the caller decide whether or not we can issue a read(). 292 */ 293 if (doread) { 294 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) { 295 syslog(LOG_ERR, "bpf: read: %m"); 296 return(0); 297 } else { 298 bp = BpfPkt; 299 ep = BpfPkt + cc; 300 } 301 } 302 303 #define bhp ((struct bpf_hdr *)bp) 304 /* 305 * If there is a new packet in the buffer, stuff it into `rconn' 306 * and return a success indication. 307 */ 308 if (bp < ep) { 309 datlen = bhp->bh_datalen; 310 caplen = bhp->bh_caplen; 311 hdrlen = bhp->bh_hdrlen; 312 313 if (caplen != datlen) 314 syslog(LOG_ERR, 315 "bpf: short packet dropped (%d of %d bytes)", 316 caplen, datlen); 317 else if (caplen > (int)sizeof(struct rmp_packet)) 318 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)", 319 caplen); 320 else { 321 rconn->rmplen = caplen; 322 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp, 323 sizeof(struct timeval)); 324 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, 325 caplen); 326 } 327 bp += BPF_WORDALIGN(caplen + hdrlen); 328 return(1); 329 } 330 #undef bhp 331 332 return(0); 333 } 334 335 /* 336 ** BpfWrite -- Write packet to BPF device. 337 ** 338 ** Parameters: 339 ** rconn - packet to send. 340 ** 341 ** Returns: 342 ** True if write succeeded, False otherwise. 343 ** 344 ** Side Effects: 345 ** None. 346 */ 347 int 348 BpfWrite(RMPCONN *rconn) 349 { 350 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) { 351 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn)); 352 return(0); 353 } 354 355 return(1); 356 } 357 358 /* 359 ** BpfClose -- Close a BPF device. 360 ** 361 ** Parameters: 362 ** None. 363 ** 364 ** Returns: 365 ** Nothing. 366 ** 367 ** Side Effects: 368 ** None. 369 */ 370 void 371 BpfClose(void) 372 { 373 struct ifreq ifr; 374 375 if (BpfPkt != NULL) { 376 free((char *)BpfPkt); 377 BpfPkt = NULL; 378 } 379 380 if (BpfFd == -1) 381 return; 382 383 #ifdef MSG_EOR 384 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2; 385 #endif 386 ifr.ifr_addr.sa_family = AF_UNSPEC; 387 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], 388 RMP_ADDRLEN); 389 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0) 390 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0); 391 392 (void) close(BpfFd); 393 BpfFd = -1; 394 } 395
Indexes created Mon Sep 22 13:09:51 GMT 2025