pcap-nit.c revision 98530 
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#ifndef lint
22static const char rcsid[] =
23    "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.41 2001/12/10 07:14:18 guy Exp $ (LBL)";
24#endif
25
26#ifdef HAVE_CONFIG_H
27#include "config.h"
28#endif
29
30#include <sys/types.h>
31#include <sys/time.h>
32#include <sys/timeb.h>
33#include <sys/file.h>
34#include <sys/ioctl.h>
35#include <sys/socket.h>
36
37#include <net/if.h>
38#include <net/nit.h>
39
40#include <netinet/in.h>
41#include <netinet/in_systm.h>
42#include <netinet/ip.h>
43#include <netinet/if_ether.h>
44#include <netinet/ip_var.h>
45#include <netinet/udp.h>
46#include <netinet/udp_var.h>
47#include <netinet/tcp.h>
48#include <netinet/tcpip.h>
49
50#include <ctype.h>
51#include <errno.h>
52#include <stdio.h>
53
54#include "pcap-int.h"
55
56#ifdef HAVE_OS_PROTO_H
57#include "os-proto.h"
58#endif
59
60/*
61 * The chunk size for NIT.  This is the amount of buffering
62 * done for read calls.
63 */
64#define CHUNKSIZE (2*1024)
65
66/*
67 * The total buffer space used by NIT.
68 */
69#define BUFSPACE (4*CHUNKSIZE)
70
71/* Forwards */
72static int nit_setflags(int, int, int, char *);
73
74int
75pcap_stats(pcap_t *p, struct pcap_stat *ps)
76{
77
78	/*
79	 * "ps_recv" counts packets handed to the filter, not packets
80	 * that passed the filter.  As filtering is done in userland,
81	 * this does not include packets dropped because we ran out
82	 * of buffer space.
83	 *
84	 * "ps_drop" presumably counts packets dropped by the socket
85	 * because of flow control requirements or resource exhaustion;
86	 * it doesn't count packets dropped by the interface driver.
87	 * As filtering is done in userland, it counts packets regardless
88	 * of whether they would've passed the filter.
89	 *
90	 * These statistics don't include packets not yet read from the
91	 * kernel by libpcap or packets not yet read from libpcap by the
92	 * application.
93	 */
94	*ps = p->md.stat;
95	return (0);
96}
97
98int
99pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
100{
101	register int cc, n;
102	register struct bpf_insn *fcode = p->fcode.bf_insns;
103	register u_char *bp, *cp, *ep;
104	register struct nit_hdr *nh;
105	register int caplen;
106
107	cc = p->cc;
108	if (cc == 0) {
109		cc = read(p->fd, (char *)p->buffer, p->bufsize);
110		if (cc < 0) {
111			if (errno == EWOULDBLOCK)
112				return (0);
113			snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
114				pcap_strerror(errno));
115			return (-1);
116		}
117		bp = p->buffer;
118	} else
119		bp = p->bp;
120
121	/*
122	 * Loop through each packet.  The increment expression
123	 * rounds up to the next int boundary past the end of
124	 * the previous packet.
125	 */
126	n = 0;
127	ep = bp + cc;
128	while (bp < ep) {
129		nh = (struct nit_hdr *)bp;
130		cp = bp + sizeof(*nh);
131
132		switch (nh->nh_state) {
133
134		case NIT_CATCH:
135			break;
136
137		case NIT_NOMBUF:
138		case NIT_NOCLUSTER:
139		case NIT_NOSPACE:
140			p->md.stat.ps_drop = nh->nh_dropped;
141			continue;
142
143		case NIT_SEQNO:
144			continue;
145
146		default:
147			snprintf(p->errbuf, sizeof(p->errbuf),
148			    "bad nit state %d", nh->nh_state);
149			return (-1);
150		}
151		++p->md.stat.ps_recv;
152		bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
153		    sizeof(int) - 1) & ~(sizeof(int) - 1));
154
155		caplen = nh->nh_wirelen;
156		if (caplen > p->snapshot)
157			caplen = p->snapshot;
158		if (bpf_filter(fcode, cp, nh->nh_wirelen, caplen)) {
159			struct pcap_pkthdr h;
160			h.ts = nh->nh_timestamp;
161			h.len = nh->nh_wirelen;
162			h.caplen = caplen;
163			(*callback)(user, &h, cp);
164			if (++n >= cnt && cnt >= 0) {
165				p->cc = ep - bp;
166				p->bp = bp;
167				return (n);
168			}
169		}
170	}
171	p->cc = 0;
172	return (n);
173}
174
175static int
176nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
177{
178	struct nit_ioc nioc;
179
180	memset(&nioc, 0, sizeof(nioc));
181	nioc.nioc_bufspace = BUFSPACE;
182	nioc.nioc_chunksize = CHUNKSIZE;
183	nioc.nioc_typetomatch = NT_ALLTYPES;
184	nioc.nioc_snaplen = p->snapshot;
185	nioc.nioc_bufalign = sizeof(int);
186	nioc.nioc_bufoffset = 0;
187
188	if (to_ms != 0) {
189		nioc.nioc_flags |= NF_TIMEOUT;
190		nioc.nioc_timeout.tv_sec = to_ms / 1000;
191		nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
192	}
193	if (promisc)
194		nioc.nioc_flags |= NF_PROMISC;
195
196	if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
197		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
198		    pcap_strerror(errno));
199		return (-1);
200	}
201	return (0);
202}
203
204pcap_t *
205pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
206{
207	int fd;
208	struct sockaddr_nit snit;
209	register pcap_t *p;
210
211	p = (pcap_t *)malloc(sizeof(*p));
212	if (p == NULL) {
213		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
214		return (NULL);
215	}
216
217	if (snaplen < 96)
218		/*
219		 * NIT requires a snapshot length of at least 96.
220		 */
221		snaplen = 96;
222
223	memset(p, 0, sizeof(*p));
224	p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
225	if (fd < 0) {
226		snprintf(ebuf, PCAP_ERRBUF_SIZE,
227		    "socket: %s", pcap_strerror(errno));
228		goto bad;
229	}
230	snit.snit_family = AF_NIT;
231	(void)strncpy(snit.snit_ifname, device, NITIFSIZ);
232
233	if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
234		snprintf(ebuf, PCAP_ERRBUF_SIZE,
235		    "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
236		goto bad;
237	}
238	p->snapshot = snaplen;
239	nit_setflags(p->fd, promisc, to_ms, ebuf);
240
241	/*
242	 * NIT supports only ethernets.
243	 */
244	p->linktype = DLT_EN10MB;
245
246	p->bufsize = BUFSPACE;
247	p->buffer = (u_char *)malloc(p->bufsize);
248	if (p->buffer == NULL) {
249		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
250		goto bad;
251	}
252	return (p);
253 bad:
254	if (fd >= 0)
255		close(fd);
256	free(p);
257	return (NULL);
258}
259
260int
261pcap_setfilter(pcap_t *p, struct bpf_program *fp)
262{
263
264	if (install_bpf_program(p, fp) < 0)
265		return (-1);
266	return (0);
267}
268