2 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
3 * The Regents of the University of California. All rights reserved.
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
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.
21 * packet filter subroutines for tcpdump
22 * Extraction/creation by Jeffrey Mogul, DECWRL
26 static const char rcsid[] =
27 "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.65 2001/12/10 07:14:19 guy Exp $ (LBL)";
34 #include <sys/types.h>
36 #include <sys/timeb.h>
37 #include <sys/socket.h>
39 #include <sys/ioctl.h>
40 #include <net/pfilt.h>
46 #include <netinet/in.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/ip.h>
49 #include <netinet/if_ether.h>
50 #include <netinet/ip_var.h>
51 #include <netinet/udp.h>
52 #include <netinet/udp_var.h>
53 #include <netinet/tcp.h>
54 #include <netinet/tcpip.h>
66 #ifdef HAVE_OS_PROTO_H
71 * BUFSPACE is the size in bytes of the packet read buffer. Most tcpdump
72 * applications aren't going to need more than 200 bytes of packet header
73 * and the read shouldn't return more packets than packetfilter's internal
74 * queue limit (bounded at 256).
76 #define BUFSPACE (200 * 256)
79 pcap_read(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
81 register u_char *p, *bp;
82 struct bpf_insn *fcode;
83 register int cc, n, buflen, inc;
84 register struct enstamp *sp;
92 fcode = pc->md.use_bpf ? NULL : pc->fcode.bf_insns;
96 cc = read(pc->fd, (char *)pc->buffer + pc->offset, pc->bufsize);
98 if (errno == EWOULDBLOCK)
100 if (errno == EINVAL &&
101 lseek(pc->fd, 0L, SEEK_CUR) + pc->bufsize < 0) {
103 * Due to a kernel bug, after 2^31 bytes,
104 * the kernel file offset overflows and
105 * read fails with EINVAL. The lseek()
106 * to 0 will fix things.
108 (void)lseek(pc->fd, 0L, SEEK_SET);
111 snprintf(pc->errbuf, sizeof(pc->errbuf), "pf read: %s",
112 pcap_strerror(errno));
115 bp = pc->buffer + pc->offset;
119 * Loop through each packet.
123 if (pc->linktype == DLT_FDDI)
129 if (cc < sizeof(*sp)) {
130 snprintf(pc->errbuf, sizeof(pc->errbuf),
131 "pf short read (%d)", cc);
137 memcpy((char *)sp, (char *)bp, sizeof(*sp));
140 sp = (struct enstamp *)bp;
141 if (sp->ens_stamplen != sizeof(*sp)) {
142 snprintf(pc->errbuf, sizeof(pc->errbuf),
143 "pf short stamplen (%d)",
148 p = bp + sp->ens_stamplen;
149 buflen = sp->ens_count;
150 if (buflen > pc->snapshot)
151 buflen = pc->snapshot;
153 /* Calculate inc before possible pad update */
154 inc = ENALIGN(buflen + sp->ens_stamplen);
162 pc->md.TotDrops += sp->ens_dropped;
163 pc->md.TotMissed = sp->ens_ifoverflows;
164 if (pc->md.OrigMissed < 0)
165 pc->md.OrigMissed = pc->md.TotMissed;
168 * Short-circuit evaluation: if using BPF filter
169 * in kernel, no need to do it now.
172 bpf_filter(fcode, p, sp->ens_count, buflen)) {
173 struct pcap_pkthdr h;
174 pc->md.TotAccepted++;
175 h.ts = sp->ens_tstamp;
177 h.len = sp->ens_count - pad;
179 h.len = sp->ens_count;
182 (*callback)(user, &h, p);
183 if (++n >= cnt && cnt > 0) {
195 pcap_stats(pcap_t *p, struct pcap_stat *ps)
199 * If packet filtering is being done in the kernel:
201 * "ps_recv" counts only packets that passed the filter.
202 * This does not include packets dropped because we
203 * ran out of buffer space. (XXX - perhaps it should,
204 * by adding "ps_drop" to "ps_recv", for compatibility
205 * with some other platforms. On the other hand, on
206 * some platforms "ps_recv" counts only packets that
207 * passed the filter, and on others it counts packets
208 * that didn't pass the filter....)
210 * "ps_drop" counts packets that passed the kernel filter
211 * (if any) but were dropped because the input queue was
214 * "ps_ifdrop" counts packets dropped by the network
215 * inteface (regardless of whether they would have passed
216 * the input filter, of course).
218 * If packet filtering is not being done in the kernel:
220 * "ps_recv" counts only packets that passed the filter.
222 * "ps_drop" counts packets that were dropped because the
223 * input queue was full, regardless of whether they passed
224 * the userland filter.
226 * "ps_ifdrop" counts packets dropped by the network
227 * inteface (regardless of whether they would have passed
228 * the input filter, of course).
230 * These statistics don't include packets not yet read from
231 * the kernel by libpcap, but they may include packets not
232 * yet read from libpcap by the application.
234 ps->ps_recv = p->md.TotAccepted;
235 ps->ps_drop = p->md.TotDrops;
236 ps->ps_ifdrop = p->md.TotMissed - p->md.OrigMissed;
241 pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
245 int backlog = -1; /* request the most */
246 struct enfilter Filter;
247 struct endevp devparams;
249 p = (pcap_t *)malloc(sizeof(*p));
251 snprintf(ebuf, PCAP_ERRBUF_SIZE,
252 "pcap_open_live: %s", pcap_strerror(errno));
255 memset(p, 0, sizeof(*p));
256 p->fd = pfopen(device, O_RDONLY);
258 snprintf(ebuf, PCAP_ERRBUF_SIZE, "pf open: %s: %s\n\
259 your system may not be properly configured; see \"man packetfilter(4)\"\n",
260 device, pcap_strerror(errno));
263 p->md.OrigMissed = -1;
264 enmode = ENTSTAMP|ENBATCH|ENNONEXCL;
267 if (ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode) < 0) {
268 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCMBIS: %s",
269 pcap_strerror(errno));
273 /* Try to set COPYALL mode so that we see packets to ourself */
275 (void)ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode);/* OK if this fails */
277 /* set the backlog */
278 if (ioctl(p->fd, EIOCSETW, (caddr_t)&backlog) < 0) {
279 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSETW: %s",
280 pcap_strerror(errno));
283 /* discover interface type */
284 if (ioctl(p->fd, EIOCDEVP, (caddr_t)&devparams) < 0) {
285 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCDEVP: %s",
286 pcap_strerror(errno));
289 /* HACK: to compile prior to Ultrix 4.2 */
293 switch (devparams.end_dev_type) {
296 p->linktype = DLT_EN10MB;
301 p->linktype = DLT_FDDI;
306 p->linktype = DLT_SLIP;
312 p->linktype = DLT_PPP;
319 * It appears to use Ethernet framing, at least on
322 p->linktype = DLT_EN10MB;
329 p->linktype = DLT_IEEE802;
335 * XXX - what about ENDT_IEEE802? The pfilt.h header
336 * file calls this "IEEE 802 networks (non-Ethernet)",
337 * but that doesn't specify a specific link layer type;
338 * it could be 802.4, or 802.5 (except that 802.5 is
339 * ENDT_TRN), or 802.6, or 802.11, or.... That's why
340 * DLT_IEEE802 was hijacked to mean Token Ring in various
341 * BSDs, and why we went along with that hijacking.
343 * XXX - what about ENDT_HDLC and ENDT_NULL?
344 * Presumably, as ENDT_OTHER is just "Miscellaneous
345 * framing", there's not much we can do, as that
346 * doesn't specify a particular type of header.
348 snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown data-link type %lu",
349 devparams.end_dev_type);
354 if (p->linktype == DLT_FDDI)
355 /* packetfilter includes the padding in the snapshot */
356 snaplen += pcap_fddipad;
358 if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&snaplen) < 0) {
359 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCTRUNCATE: %s",
360 pcap_strerror(errno));
363 p->snapshot = snaplen;
364 /* accept all packets */
365 memset(&Filter, 0, sizeof(Filter));
366 Filter.enf_Priority = 37; /* anything > 2 */
367 Filter.enf_FilterLen = 0; /* means "always true" */
368 if (ioctl(p->fd, EIOCSETF, (caddr_t)&Filter) < 0) {
369 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSETF: %s",
370 pcap_strerror(errno));
375 struct timeval timeout;
376 timeout.tv_sec = to_ms / 1000;
377 timeout.tv_usec = (to_ms * 1000) % 1000000;
378 if (ioctl(p->fd, EIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {
379 snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSRTIMEOUT: %s",
380 pcap_strerror(errno));
384 p->bufsize = BUFSPACE;
385 p->buffer = (u_char*)malloc(p->bufsize + p->offset);
396 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
399 * See if BIOCSETF works. If it does, the kernel supports
400 * BPF-style filters, and we do not need to do post-filtering.
402 p->md.use_bpf = (ioctl(p->fd, BIOCSETF, (caddr_t)fp) >= 0);
404 struct bpf_version bv;
406 if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) < 0) {
407 snprintf(p->errbuf, sizeof(p->errbuf),
408 "BIOCVERSION: %s", pcap_strerror(errno));
411 else if (bv.bv_major != BPF_MAJOR_VERSION ||
412 bv.bv_minor < BPF_MINOR_VERSION) {
414 "requires bpf language %d.%d or higher; kernel is %d.%d",
415 BPF_MAJOR_VERSION, BPF_MINOR_VERSION,
416 bv.bv_major, bv.bv_minor);
417 /* don't give up, just be inefficient */
421 if (install_bpf_program(p, fp) < 0)
425 /*XXX this goes in tcpdump*/
427 fprintf(stderr, "tcpdump: Using kernel BPF filter\n");
429 fprintf(stderr, "tcpdump: Filtering in user process\n");