aboutsummaryrefslogtreecommitdiffstats
path: root/pcap-snoop.c
blob: c532b309839bb647ef978458064ab814884d8248 (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
/*
 * Copyright (c) 1993, 1994, 1995, 1996, 1997
 *	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-snoop.c,v 1.27 2000-07-29 08:03:57 assar Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>

#include <net/raw.h>
#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>

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

#include "pcap-int.h"

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

int
pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
	int cc;
	register struct snoopheader *sh;
	register int datalen;
	register int caplen;
	register u_char *cp;

again:
	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);			/* XXX */
		}
		snprintf(p->errbuf, sizeof(p->errbuf),
		    "read: %s", pcap_strerror(errno));
		return (-1);
	}
	sh = (struct snoopheader *)p->buffer;
	datalen = sh->snoop_packetlen;
	caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
	cp = (u_char *)(sh + 1) + p->offset;		/* XXX */

	if (p->fcode.bf_insns == NULL ||
	    bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
		struct pcap_pkthdr h;
		++p->md.stat.ps_recv;
		h.ts = sh->snoop_timestamp;
		h.len = datalen;
		h.caplen = caplen;
		(*callback)(user, &h, cp);
		return (1);
	}
	return (0);
}

int
pcap_stats(pcap_t *p, struct pcap_stat *ps)
{
	register struct rawstats *rs;
	struct rawstats rawstats;

	rs = &rawstats;
	memset(rs, 0, sizeof(*rs));
	if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
		snprintf(p->errbuf, sizeof(p->errbuf),
		    "SIOCRAWSTATS: %s", pcap_strerror(errno));
		return (-1);
	}

	p->md.stat.ps_drop =
	    rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
	    rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;

	*ps = p->md.stat;
	return (0);
}

/* XXX can't disable promiscuous */
pcap_t *
pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
{
	int fd;
	struct sockaddr_raw sr;
	struct snoopfilter sf;
	u_int v;
	int ll_hdrlen;
	int snooplen;
	pcap_t *p;
	struct ifreq ifr;

	p = (pcap_t *)malloc(sizeof(*p));
	if (p == NULL) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
		    pcap_strerror(errno));
		return (NULL);
	}
	memset(p, 0, sizeof(*p));
	fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
	if (fd < 0) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
		    pcap_strerror(errno));
		goto bad;
	}
	p->fd = fd;
	memset(&sr, 0, sizeof(sr));
	sr.sr_family = AF_RAW;
	(void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
	if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
		    pcap_strerror(errno));
		goto bad;
	}
	memset(&sf, 0, sizeof(sf));
	if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
		    pcap_strerror(errno));
		goto bad;
	}
	v = 64 * 1024;
	(void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
	/*
	 * XXX hack - map device name to link layer type
	 */
	if (strncmp("et", device, 2) == 0 ||	/* Challenge 10 Mbit */
	    strncmp("ec", device, 2) == 0 ||	/* Indigo/Indy 10 Mbit,
						   O2 10/100 */
	    strncmp("ef", device, 2) == 0 ||	/* O200/2000 10/100 Mbit */
	    strncmp("gfe", device, 3) == 0 ||	/* GIO 100 Mbit */
	    strncmp("fxp", device, 3) == 0 ||	/* Challenge VME Enet */
	    strncmp("ep", device, 2) == 0 ||	/* Challenge 8x10 Mbit EPLEX */
	    strncmp("vfe", device, 3) == 0 ||	/* Challenge VME 100Mbit */
	    strncmp("fa", device, 2) == 0 ||
	    strncmp("qaa", device, 3) == 0 ||
	    strncmp("el", device, 2) == 0) {
		p->linktype = DLT_EN10MB;
		p->offset = RAW_HDRPAD(sizeof(struct ether_header));
		ll_hdrlen = sizeof(struct ether_header);
	} else if (strncmp("ipg", device, 3) == 0 ||
		   strncmp("rns", device, 3) == 0 ||	/* O2/200/2000 FDDI */
		   strncmp("xpi", device, 3) == 0) {
		p->linktype = DLT_FDDI;
		p->offset = 3;				/* XXX yeah? */
		ll_hdrlen = 13;
	} else if (strncmp("ppp", device, 3) == 0) {
		p->linktype = DLT_RAW;
		ll_hdrlen = 0;	/* DLT_RAW meaning "no PPP header, just the IP packet"? */
	} else if (strncmp("lo", device, 2) == 0) {
		p->linktype = DLT_NULL;
		ll_hdrlen = 4;	/* is this just like BSD's loopback device? */
	} else {
		snprintf(ebuf, PCAP_ERRBUF_SIZE,
		    "snoop: unknown physical layer type");
		goto bad;
	}
#ifdef SIOCGIFMTU
	/*
	 * XXX - IRIX appears to give you an error if you try to set the
	 * capture length to be greater than the MTU, so let's try to get
	 * the MTU first and, if that succeeds, trim the snap length
	 * to be no greater than the MTU.
	 */
	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
	if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
		    pcap_strerror(errno));
		goto bad;
	}
	/*
	 * OK, we got it.
	 *
	 * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
	 * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
	 * structure, others don't.
	 *
	 * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
	 * we define it as "ifr_metric", as using that field appears to
	 * work on the versions that lack "ifr_mtu" (and, on those that
	 * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
	 * members of the "ifr_ifru" union, which suggests that they
	 * may be interchangeable in this case).
	 */
#ifndef ifr_mtu
#define ifr_mtu	ifr_metric
#endif
	if (snaplen > ifr.ifr_mtu)
		snaplen = ifr.ifr_mtu;
#endif

	/*
	 * The argument to SIOCSNOOPLEN is the number of link-layer
	 * payload bytes to capture - it doesn't count link-layer
	 * header bytes.
	 */
	snooplen = snaplen - ll_hdrlen;
	if (snooplen < 0)
		snooplen = 0;
	if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
		    pcap_strerror(errno));
		goto bad;
	}
	p->snapshot = snaplen;
	v = 1;
	if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
		    pcap_strerror(errno));
		goto bad;
	}

	p->bufsize = 4096;				/* XXX */
	p->buffer = (u_char *)malloc(p->bufsize);
	if (p->buffer == NULL) {
		snprintf(ebuf, PCAP_ERRBUF_SIZE, "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)
{

	p->fcode = *fp;
	return (0);
}