summaryrefslogtreecommitdiffstats
path: root/contrib/libpcap/pcap-bpf.c
blob: 9c9a554575aef9e26a53b96bff29d513e6e844a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
/*
 * Copyright (c) 1993, 1994, 1995, 1996, 1998
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.32 1999/10/19 15:18:30 itojun Exp $ (LBL)";
#endif

#include <sys/param.h>			/* optionally get BSD define */
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/ioctl.h>

#include <net/if.h>

#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pcap-int.h"

#include "gnuc.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

#include "gencode.h"

int
pcap_stats(pcap_t *p, struct pcap_stat *ps)
{
	struct bpf_stat s;

	if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) {
		sprintf(p->errbuf, "BIOCGSTATS: %s", pcap_strerror(errno));
		return (-1);
	}

	ps->ps_recv = s.bs_recv;
	ps->ps_drop = s.bs_drop;
	return (0);
}

int
pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
	int cc;
	int n = 0;
	register u_char *bp, *ep;

 again:
	cc = p->cc;
	if (p->cc == 0) {
		cc = read(p->fd, (char *)p->buffer, p->bufsize);
		if (cc < 0) {
			/* Don't choke when we get ptraced */
			switch (errno) {

			case EINTR:
				goto again;

			case EWOULDBLOCK:
				return (0);
#if defined(sun) && !defined(BSD)
			/*
			 * Due to a SunOS bug, after 2^31 bytes, the kernel
			 * file offset overflows and read fails with EINVAL.
			 * The lseek() to 0 will fix things.
			 */
			case EINVAL:
				if (lseek(p->fd, 0L, SEEK_CUR) +
				    p->bufsize < 0) {
					(void)lseek(p->fd, 0L, SEEK_SET);
					goto again;
				}
				/* fall through */
#endif
			}
			sprintf(p->errbuf, "read: %s", pcap_strerror(errno));
			return (-1);
		}
		bp = p->buffer;
	} else
		bp = p->bp;

	/*
	 * Loop through each packet.
	 */
#define bhp ((struct bpf_hdr *)bp)
	ep = bp + cc;
	while (bp < ep) {
		register int caplen, hdrlen;
		caplen = bhp->bh_caplen;
		hdrlen = bhp->bh_hdrlen;
		/*
		 * XXX A bpf_hdr matches a pcap_pkthdr.
		 */
		(*callback)(user, (struct pcap_pkthdr*)bp, bp + hdrlen);
		bp += BPF_WORDALIGN(caplen + hdrlen);
		if (++n >= cnt && cnt > 0) {
			p->bp = bp;
			p->cc = ep - bp;
			return (n);
		}
	}
#undef bhp
	p->cc = 0;
	return (n);
}

static inline int
bpf_open(pcap_t *p, char *errbuf)
{
	int fd;
	int n = 0;
	char device[sizeof "/dev/bpf000"];

	/*
	 * Go through all the minors and find one that isn't in use.
	 */
	do {
		(void)sprintf(device, "/dev/bpf%d", n++);
		fd = open(device, O_RDONLY);
	} while (fd < 0 && errno == EBUSY);

	/*
	 * XXX better message for all minors used
	 */
	if (fd < 0)
		sprintf(errbuf, "%s: %s", device, pcap_strerror(errno));

	return (fd);
}

pcap_t *
pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
{
	int fd;
	struct ifreq ifr;
	struct bpf_version bv;
	u_int v;
	pcap_t *p;

	p = (pcap_t *)malloc(sizeof(*p));
	if (p == NULL) {
		sprintf(ebuf, "malloc: %s", pcap_strerror(errno));
		return (NULL);
	}
	bzero(p, sizeof(*p));
	fd = bpf_open(p, ebuf);
	if (fd < 0)
		goto bad;

	p->fd = fd;
	p->snapshot = snaplen;

	if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) {
		sprintf(ebuf, "BIOCVERSION: %s", pcap_strerror(errno));
		goto bad;
	}
	if (bv.bv_major != BPF_MAJOR_VERSION ||
	    bv.bv_minor < BPF_MINOR_VERSION) {
		sprintf(ebuf, "kernel bpf filter out of date");
		goto bad;
	}
	v = 32768;	/* XXX this should be a user-accessible hook */
	/* Ignore the return value - this is because the call fails on
	 * BPF systems that don't have kernel malloc.  And if the call
	 * fails, it's no big deal, we just continue to use the standard
	 * buffer size.
	 */
	(void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);

	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
	if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
		sprintf(ebuf, "%s: %s", device, pcap_strerror(errno));
		goto bad;
	}
	/* Get the data link layer type. */
	if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) {
		sprintf(ebuf, "BIOCGDLT: %s", pcap_strerror(errno));
		goto bad;
	}
#ifdef __OpenBSD__
	switch (v) {
	case DLT_LOOP:
		v = DLT_NULL;
		break;
	}
#endif
#if _BSDI_VERSION - 0 >= 199510
	/* The SLIP and PPP link layer header changed in BSD/OS 2.1 */
	switch (v) {

	case DLT_SLIP:
		v = DLT_SLIP_BSDOS;
		break;

	case DLT_PPP:
		v = DLT_PPP_BSDOS;
		break;

	case 11:	/*DLT_FR*/
		v = DLT_RAW;	/*XXX*/
		break;

	case 12:	/*DLT_C_HDLC*/
		v = DLT_CHDLC;
		break;
	}
#endif
	p->linktype = v;

	/* set timeout */
	if (to_ms != 0) {
		struct timeval to;
		to.tv_sec = to_ms / 1000;
		to.tv_usec = (to_ms * 1000) % 1000000;
		if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) {
			sprintf(ebuf, "BIOCSRTIMEOUT: %s",
				pcap_strerror(errno));
			goto bad;
		}
	}
	if (promisc)
		/* set promiscuous mode, okay if it fails */
		(void)ioctl(p->fd, BIOCPROMISC, NULL);

	if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) {
		sprintf(ebuf, "BIOCGBLEN: %s", pcap_strerror(errno));
		goto bad;
	}
	p->bufsize = v;
	p->buffer = (u_char *)malloc(p->bufsize);
	if (p->buffer == NULL) {
		sprintf(ebuf, "malloc: %s", pcap_strerror(errno));
		goto bad;
	}

	return (p);
 bad:
	(void)close(fd);
	free(p);
	return (NULL);
}

int
pcap_setfilter(pcap_t *p, struct bpf_program *fp)
{
	/*
	 * It looks that BPF code generated by gen_protochain() is not
	 * compatible with some of kernel BPF code (for example BSD/OS 3.1).
	 * Take a safer side for now.
	 */
	if (no_optimize)
		p->fcode = *fp;
	else if (p->sf.rfile != NULL)
		p->fcode = *fp;
	else if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
		sprintf(p->errbuf, "BIOCSETF: %s", pcap_strerror(errno));
		return (-1);
	}
	return (0);
}
OpenPOWER on IntegriCloud