1 /* 2 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 * 21 * Modifications made to accommodate the new SunOS4.0 NIT facility by 22 * Micky Liu, micky (at) cunixc.cc.columbia.edu, Columbia University in May, 1989. 23 * This module now handles the STREAMS based NIT. 24 */ 25 26 #ifndef lint 27 static const char rcsid[] _U_ = 28 "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.72.2.1 2005/05/03 18:54:38 guy Exp $ (LBL)"; 29 #endif 30 31 #ifdef HAVE_CONFIG_H 32 #include "config.h" 33 #endif 34 35 #include <sys/types.h> 36 #include <sys/time.h> 37 #include <sys/timeb.h> 38 #include <sys/dir.h> 39 #include <sys/fcntlcom.h> 40 #include <sys/file.h> 41 #include <sys/ioctl.h> 42 #include <sys/socket.h> 43 #include <sys/stropts.h> 44 45 #include <net/if.h> 46 #include <net/nit.h> 47 #include <net/nit_if.h> 48 #include <net/nit_pf.h> 49 #include <net/nit_buf.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_systm.h> 53 #include <netinet/ip.h> 54 #include <netinet/if_ether.h> 55 #include <netinet/ip_var.h> 56 #include <netinet/udp.h> 57 #include <netinet/udp_var.h> 58 #include <netinet/tcp.h> 59 #include <netinet/tcpip.h> 60 61 #include <ctype.h> 62 #include <errno.h> 63 #include <stdio.h> 64 #include <string.h> 65 #include <unistd.h> 66 67 #include "pcap-int.h" 68 69 #ifdef HAVE_OS_PROTO_H 70 #include "os-proto.h" 71 #endif 72 73 /* 74 * The chunk size for NIT. This is the amount of buffering 75 * done for read calls. 76 */ 77 #define CHUNKSIZE (2*1024) 78 79 /* 80 * The total buffer space used by NIT. 81 */ 82 #define BUFSPACE (4*CHUNKSIZE) 83 84 /* Forwards */ 85 static int nit_setflags(int, int, int, char *); 86 87 static int 88 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps) 89 { 90 91 /* 92 * "ps_recv" counts packets handed to the filter, not packets 93 * that passed the filter. As filtering is done in userland, 94 * this does not include packets dropped because we ran out 95 * of buffer space. 96 * 97 * "ps_drop" counts packets dropped inside the "/dev/nit" 98 * device because of flow control requirements or resource 99 * exhaustion; it doesn't count packets dropped by the 100 * interface driver, or packets dropped upstream. As filtering 101 * is done in userland, it counts packets regardless of whether 102 * they would've passed the filter. 103 * 104 * These statistics don't include packets not yet read from the 105 * kernel by libpcap or packets not yet read from libpcap by the 106 * application. 107 */ 108 *ps = p->md.stat; 109 return (0); 110 } 111 112 static int 113 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 114 { 115 register int cc, n; 116 register struct bpf_insn *fcode = p->fcode.bf_insns; 117 register u_char *bp, *cp, *ep; 118 register struct nit_bufhdr *hdrp; 119 register struct nit_iftime *ntp; 120 register struct nit_iflen *nlp; 121 register struct nit_ifdrops *ndp; 122 register int caplen; 123 124 cc = p->cc; 125 if (cc == 0) { 126 cc = read(p->fd, (char *)p->buffer, p->bufsize); 127 if (cc < 0) { 128 if (errno == EWOULDBLOCK) 129 return (0); 130 snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s", 131 pcap_strerror(errno)); 132 return (-1); 133 } 134 bp = p->buffer; 135 } else 136 bp = p->bp; 137 138 /* 139 * loop through each snapshot in the chunk 140 */ 141 n = 0; 142 ep = bp + cc; 143 while (bp < ep) { 144 /* 145 * Has "pcap_breakloop()" been called? 146 * If so, return immediately - if we haven't read any 147 * packets, clear the flag and return -2 to indicate 148 * that we were told to break out of the loop, otherwise 149 * leave the flag set, so that the *next* call will break 150 * out of the loop without having read any packets, and 151 * return the number of packets we've processed so far. 152 */ 153 if (p->break_loop) { 154 if (n == 0) { 155 p->break_loop = 0; 156 return (-2); 157 } else { 158 p->bp = bp; 159 p->cc = ep - bp; 160 return (n); 161 } 162 } 163 164 ++p->md.stat.ps_recv; 165 cp = bp; 166 167 /* get past NIT buffer */ 168 hdrp = (struct nit_bufhdr *)cp; 169 cp += sizeof(*hdrp); 170 171 /* get past NIT timer */ 172 ntp = (struct nit_iftime *)cp; 173 cp += sizeof(*ntp); 174 175 ndp = (struct nit_ifdrops *)cp; 176 p->md.stat.ps_drop = ndp->nh_drops; 177 cp += sizeof *ndp; 178 179 /* get past packet len */ 180 nlp = (struct nit_iflen *)cp; 181 cp += sizeof(*nlp); 182 183 /* next snapshot */ 184 bp += hdrp->nhb_totlen; 185 186 caplen = nlp->nh_pktlen; 187 if (caplen > p->snapshot) 188 caplen = p->snapshot; 189 190 if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) { 191 struct pcap_pkthdr h; 192 h.ts = ntp->nh_timestamp; 193 h.len = nlp->nh_pktlen; 194 h.caplen = caplen; 195 (*callback)(user, &h, cp); 196 if (++n >= cnt && cnt >= 0) { 197 p->cc = ep - bp; 198 p->bp = bp; 199 return (n); 200 } 201 } 202 } 203 p->cc = 0; 204 return (n); 205 } 206 207 static int 208 pcap_inject_snit(pcap_t *p, const void *buf, size_t size) 209 { 210 struct strbuf ctl, data; 211 212 /* 213 * XXX - can we just do 214 * 215 ret = write(pd->f, buf, size); 216 */ 217 ctl.len = sizeof(*sa); /* XXX - what was this? */ 218 ctl.buf = (char *)sa; 219 data.buf = buf; 220 data.len = size; 221 ret = putmsg(p->fd, &ctl, &data); 222 if (ret == -1) { 223 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", 224 pcap_strerror(errno)); 225 return (-1); 226 } 227 return (ret); 228 } 229 230 static int 231 nit_setflags(int fd, int promisc, int to_ms, char *ebuf) 232 { 233 bpf_u_int32 flags; 234 struct strioctl si; 235 struct timeval timeout; 236 237 si.ic_timout = INFTIM; 238 if (to_ms != 0) { 239 timeout.tv_sec = to_ms / 1000; 240 timeout.tv_usec = (to_ms * 1000) % 1000000; 241 si.ic_cmd = NIOCSTIME; 242 si.ic_len = sizeof(timeout); 243 si.ic_dp = (char *)&timeout; 244 if (ioctl(fd, I_STR, (char *)&si) < 0) { 245 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s", 246 pcap_strerror(errno)); 247 return (-1); 248 } 249 } 250 flags = NI_TIMESTAMP | NI_LEN | NI_DROPS; 251 if (promisc) 252 flags |= NI_PROMISC; 253 si.ic_cmd = NIOCSFLAGS; 254 si.ic_len = sizeof(flags); 255 si.ic_dp = (char *)&flags; 256 if (ioctl(fd, I_STR, (char *)&si) < 0) { 257 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s", 258 pcap_strerror(errno)); 259 return (-1); 260 } 261 return (0); 262 } 263 264 pcap_t * 265 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, 266 char *ebuf) 267 { 268 struct strioctl si; /* struct for ioctl() */ 269 struct ifreq ifr; /* interface request struct */ 270 int chunksize = CHUNKSIZE; 271 int fd; 272 static char dev[] = "/dev/nit"; 273 register pcap_t *p; 274 275 p = (pcap_t *)malloc(sizeof(*p)); 276 if (p == NULL) { 277 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE); 278 return (NULL); 279 } 280 281 if (snaplen < 96) 282 /* 283 * NIT requires a snapshot length of at least 96. 284 */ 285 snaplen = 96; 286 287 memset(p, 0, sizeof(*p)); 288 /* 289 * Initially try a read/write open (to allow the inject 290 * method to work). If that fails due to permission 291 * issues, fall back to read-only. This allows a 292 * non-root user to be granted specific access to pcap 293 * capabilities via file permissions. 294 * 295 * XXX - we should have an API that has a flag that 296 * controls whether to open read-only or read-write, 297 * so that denial of permission to send (or inability 298 * to send, if sending packets isn't supported on 299 * the device in question) can be indicated at open 300 * time. 301 */ 302 p->fd = fd = open(dev, O_RDWR); 303 if (fd < 0 && errno == EACCES) 304 p->fd = fd = open(dev, O_RDONLY); 305 if (fd < 0) { 306 snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev, 307 pcap_strerror(errno)); 308 goto bad; 309 } 310 311 /* arrange to get discrete messages from the STREAM and use NIT_BUF */ 312 if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) { 313 snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s", 314 pcap_strerror(errno)); 315 goto bad; 316 } 317 if (ioctl(fd, I_PUSH, "nbuf") < 0) { 318 snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s", 319 pcap_strerror(errno)); 320 goto bad; 321 } 322 /* set the chunksize */ 323 si.ic_cmd = NIOCSCHUNK; 324 si.ic_timout = INFTIM; 325 si.ic_len = sizeof(chunksize); 326 si.ic_dp = (char *)&chunksize; 327 if (ioctl(fd, I_STR, (char *)&si) < 0) { 328 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s", 329 pcap_strerror(errno)); 330 goto bad; 331 } 332 333 /* request the interface */ 334 strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 335 ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0'; 336 si.ic_cmd = NIOCBIND; 337 si.ic_len = sizeof(ifr); 338 si.ic_dp = (char *)𝔦 339 if (ioctl(fd, I_STR, (char *)&si) < 0) { 340 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s", 341 ifr.ifr_name, pcap_strerror(errno)); 342 goto bad; 343 } 344 345 /* set the snapshot length */ 346 si.ic_cmd = NIOCSSNAP; 347 si.ic_len = sizeof(snaplen); 348 si.ic_dp = (char *)&snaplen; 349 if (ioctl(fd, I_STR, (char *)&si) < 0) { 350 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s", 351 pcap_strerror(errno)); 352 goto bad; 353 } 354 p->snapshot = snaplen; 355 if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0) 356 goto bad; 357 358 (void)ioctl(fd, I_FLUSH, (char *)FLUSHR); 359 /* 360 * NIT supports only ethernets. 361 */ 362 p->linktype = DLT_EN10MB; 363 364 p->bufsize = BUFSPACE; 365 p->buffer = (u_char *)malloc(p->bufsize); 366 if (p->buffer == NULL) { 367 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE); 368 goto bad; 369 } 370 371 /* 372 * "p->fd" is an FD for a STREAMS device, so "select()" and 373 * "poll()" should work on it. 374 */ 375 p->selectable_fd = p->fd; 376 377 /* 378 * This is (presumably) a real Ethernet capture; give it a 379 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so 380 * that an application can let you choose it, in case you're 381 * capturing DOCSIS traffic that a Cisco Cable Modem 382 * Termination System is putting out onto an Ethernet (it 383 * doesn't put an Ethernet header onto the wire, it puts raw 384 * DOCSIS frames out on the wire inside the low-level 385 * Ethernet framing). 386 */ 387 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 388 /* 389 * If that fails, just leave the list empty. 390 */ 391 if (p->dlt_list != NULL) { 392 p->dlt_list[0] = DLT_EN10MB; 393 p->dlt_list[1] = DLT_DOCSIS; 394 p->dlt_count = 2; 395 } 396 397 p->read_op = pcap_read_snit; 398 p->inject_op = pcap_inject_snit; 399 p->setfilter_op = install_bpf_program; /* no kernel filtering */ 400 p->setdirection_op = NULL; /* Not implemented. */ 401 p->set_datalink_op = NULL; /* can't change data link type */ 402 p->getnonblock_op = pcap_getnonblock_fd; 403 p->setnonblock_op = pcap_setnonblock_fd; 404 p->stats_op = pcap_stats_snit; 405 p->close_op = pcap_close_common; 406 407 return (p); 408 bad: 409 if (fd >= 0) 410 close(fd); 411 free(p); 412 return (NULL); 413 } 414 415 int 416 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) 417 { 418 return (0); 419 } 420
