pcap-snoop.c revision 98530 
1/*
2 * Copyright (c) 1993, 1994, 1995, 1996, 1997
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#ifndef lint
22static const char rcsid[] =
23    "@(#) $Header: /tcpdump/master/libpcap/pcap-snoop.c,v 1.33 2001/12/10 07:14:21 guy Exp $ (LBL)";
24#endif
25
26#ifdef HAVE_CONFIG_H
27#include "config.h"
28#endif
29
30#include <sys/param.h>
31#include <sys/file.h>
32#include <sys/ioctl.h>
33#include <sys/socket.h>
34#include <sys/time.h>
35
36#include <net/raw.h>
37#include <net/if.h>
38
39#include <netinet/in.h>
40#include <netinet/in_systm.h>
41#include <netinet/ip.h>
42#include <netinet/if_ether.h>
43#include <netinet/ip_var.h>
44#include <netinet/udp.h>
45#include <netinet/udp_var.h>
46#include <netinet/tcp.h>
47#include <netinet/tcpip.h>
48
49#include <errno.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <string.h>
53#include <unistd.h>
54
55#include "pcap-int.h"
56
57#ifdef HAVE_OS_PROTO_H
58#include "os-proto.h"
59#endif
60
61int
62pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
63{
64	int cc;
65	register struct snoopheader *sh;
66	register int datalen;
67	register int caplen;
68	register u_char *cp;
69
70again:
71	cc = read(p->fd, (char *)p->buffer, p->bufsize);
72	if (cc < 0) {
73		/* Don't choke when we get ptraced */
74		switch (errno) {
75
76		case EINTR:
77				goto again;
78
79		case EWOULDBLOCK:
80			return (0);			/* XXX */
81		}
82		snprintf(p->errbuf, sizeof(p->errbuf),
83		    "read: %s", pcap_strerror(errno));
84		return (-1);
85	}
86	sh = (struct snoopheader *)p->buffer;
87	datalen = sh->snoop_packetlen;
88	caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
89	cp = (u_char *)(sh + 1) + p->offset;		/* XXX */
90
91	if (p->fcode.bf_insns == NULL ||
92	    bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
93		struct pcap_pkthdr h;
94		++p->md.stat.ps_recv;
95		h.ts = sh->snoop_timestamp;
96		h.len = datalen;
97		h.caplen = caplen;
98		(*callback)(user, &h, cp);
99		return (1);
100	}
101	return (0);
102}
103
104int
105pcap_stats(pcap_t *p, struct pcap_stat *ps)
106{
107	register struct rawstats *rs;
108	struct rawstats rawstats;
109
110	rs = &rawstats;
111	memset(rs, 0, sizeof(*rs));
112	if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
113		snprintf(p->errbuf, sizeof(p->errbuf),
114		    "SIOCRAWSTATS: %s", pcap_strerror(errno));
115		return (-1);
116	}
117
118	/*
119	 * "ifdrops" are those dropped by the network interface
120	 * due to resource shortages or hardware errors.
121	 *
122	 * "sbdrops" are those dropped due to socket buffer limits.
123	 *
124	 * As filter is done in userland, "sbdrops" counts packets
125	 * regardless of whether they would've passed the filter.
126	 *
127	 * XXX - does this count *all* Snoop or Drain sockets,
128	 * rather than just this socket?  If not, why does it have
129	 * both Snoop and Drain statistics?
130	 */
131	p->md.stat.ps_drop =
132	    rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
133	    rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
134
135	/*
136	 * "ps_recv" counts only packets that passed the filter.
137	 * As filtering is done in userland, this does not include
138	 * packets dropped because we ran out of buffer space.
139	 */
140	*ps = p->md.stat;
141	return (0);
142}
143
144/* XXX can't disable promiscuous */
145pcap_t *
146pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
147{
148	int fd;
149	struct sockaddr_raw sr;
150	struct snoopfilter sf;
151	u_int v;
152	int ll_hdrlen;
153	int snooplen;
154	pcap_t *p;
155	struct ifreq ifr;
156
157	p = (pcap_t *)malloc(sizeof(*p));
158	if (p == NULL) {
159		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
160		    pcap_strerror(errno));
161		return (NULL);
162	}
163	memset(p, 0, sizeof(*p));
164	fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
165	if (fd < 0) {
166		snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
167		    pcap_strerror(errno));
168		goto bad;
169	}
170	p->fd = fd;
171	memset(&sr, 0, sizeof(sr));
172	sr.sr_family = AF_RAW;
173	(void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
174	if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
175		snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
176		    pcap_strerror(errno));
177		goto bad;
178	}
179	memset(&sf, 0, sizeof(sf));
180	if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
181		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
182		    pcap_strerror(errno));
183		goto bad;
184	}
185	v = 64 * 1024;
186	(void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
187	/*
188	 * XXX hack - map device name to link layer type
189	 */
190	if (strncmp("et", device, 2) == 0 ||	/* Challenge 10 Mbit */
191	    strncmp("ec", device, 2) == 0 ||	/* Indigo/Indy 10 Mbit,
192						   O2 10/100 */
193	    strncmp("ef", device, 2) == 0 ||	/* O200/2000 10/100 Mbit */
194	    strncmp("gfe", device, 3) == 0 ||	/* GIO 100 Mbit */
195	    strncmp("fxp", device, 3) == 0 ||	/* Challenge VME Enet */
196	    strncmp("ep", device, 2) == 0 ||	/* Challenge 8x10 Mbit EPLEX */
197	    strncmp("vfe", device, 3) == 0 ||	/* Challenge VME 100Mbit */
198	    strncmp("fa", device, 2) == 0 ||
199	    strncmp("qaa", device, 3) == 0 ||
200	    strncmp("cip", device, 3) == 0 ||
201	    strncmp("el", device, 2) == 0) {
202		p->linktype = DLT_EN10MB;
203		p->offset = RAW_HDRPAD(sizeof(struct ether_header));
204		ll_hdrlen = sizeof(struct ether_header);
205	} else if (strncmp("ipg", device, 3) == 0 ||
206		   strncmp("rns", device, 3) == 0 ||	/* O2/200/2000 FDDI */
207		   strncmp("xpi", device, 3) == 0) {
208		p->linktype = DLT_FDDI;
209		p->offset = 3;				/* XXX yeah? */
210		ll_hdrlen = 13;
211	} else if (strncmp("ppp", device, 3) == 0) {
212		p->linktype = DLT_RAW;
213		ll_hdrlen = 0;	/* DLT_RAW meaning "no PPP header, just the IP packet"? */
214	} else if (strncmp("lo", device, 2) == 0) {
215		p->linktype = DLT_NULL;
216		ll_hdrlen = 4;	/* is this just like BSD's loopback device? */
217	} else {
218		snprintf(ebuf, PCAP_ERRBUF_SIZE,
219		    "snoop: unknown physical layer type");
220		goto bad;
221	}
222#ifdef SIOCGIFMTU
223	/*
224	 * XXX - IRIX appears to give you an error if you try to set the
225	 * capture length to be greater than the MTU, so let's try to get
226	 * the MTU first and, if that succeeds, trim the snap length
227	 * to be no greater than the MTU.
228	 */
229	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
230	if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
231		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
232		    pcap_strerror(errno));
233		goto bad;
234	}
235	/*
236	 * OK, we got it.
237	 *
238	 * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
239	 * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
240	 * structure, others don't.
241	 *
242	 * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
243	 * we define it as "ifr_metric", as using that field appears to
244	 * work on the versions that lack "ifr_mtu" (and, on those that
245	 * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
246	 * members of the "ifr_ifru" union, which suggests that they
247	 * may be interchangeable in this case).
248	 */
249#ifndef ifr_mtu
250#define ifr_mtu	ifr_metric
251#endif
252	if (snaplen > ifr.ifr_mtu)
253		snaplen = ifr.ifr_mtu;
254#endif
255
256	/*
257	 * The argument to SIOCSNOOPLEN is the number of link-layer
258	 * payload bytes to capture - it doesn't count link-layer
259	 * header bytes.
260	 */
261	snooplen = snaplen - ll_hdrlen;
262	if (snooplen < 0)
263		snooplen = 0;
264	if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
265		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
266		    pcap_strerror(errno));
267		goto bad;
268	}
269	p->snapshot = snaplen;
270	v = 1;
271	if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
272		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
273		    pcap_strerror(errno));
274		goto bad;
275	}
276
277	p->bufsize = 4096;				/* XXX */
278	p->buffer = (u_char *)malloc(p->bufsize);
279	if (p->buffer == NULL) {
280		snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
281		    pcap_strerror(errno));
282		goto bad;
283	}
284
285	return (p);
286 bad:
287	(void)close(fd);
288	free(p);
289	return (NULL);
290}
291
292int
293pcap_setfilter(pcap_t *p, struct bpf_program *fp)
294{
295
296	if (install_bpf_program(p, fp) < 0)
297		return (-1);
298	return (0);
299}
300