pcap-nit.c revision 146768 
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[] _U_ =
23    "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.57 2004/10/19 07:06:13 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
74static int
75pcap_stats_nit(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
98static int
99pcap_read_nit(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		/*
130		 * Has "pcap_breakloop()" been called?
131		 * If so, return immediately - if we haven't read any
132		 * packets, clear the flag and return -2 to indicate
133		 * that we were told to break out of the loop, otherwise
134		 * leave the flag set, so that the *next* call will break
135		 * out of the loop without having read any packets, and
136		 * return the number of packets we've processed so far.
137		 */
138		if (p->break_loop) {
139			if (n == 0) {
140				p->break_loop = 0;
141				return (-2);
142			} else {
143				p->cc = ep - bp;
144				p->bp = bp;
145				return (n);
146			}
147		}
148
149		nh = (struct nit_hdr *)bp;
150		cp = bp + sizeof(*nh);
151
152		switch (nh->nh_state) {
153
154		case NIT_CATCH:
155			break;
156
157		case NIT_NOMBUF:
158		case NIT_NOCLUSTER:
159		case NIT_NOSPACE:
160			p->md.stat.ps_drop = nh->nh_dropped;
161			continue;
162
163		case NIT_SEQNO:
164			continue;
165
166		default:
167			snprintf(p->errbuf, sizeof(p->errbuf),
168			    "bad nit state %d", nh->nh_state);
169			return (-1);
170		}
171		++p->md.stat.ps_recv;
172		bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
173		    sizeof(int) - 1) & ~(sizeof(int) - 1));
174
175		caplen = nh->nh_wirelen;
176		if (caplen > p->snapshot)
177			caplen = p->snapshot;
178		if (bpf_filter(fcode, cp, nh->nh_wirelen, caplen)) {
179			struct pcap_pkthdr h;
180			h.ts = nh->nh_timestamp;
181			h.len = nh->nh_wirelen;
182			h.caplen = caplen;
183			(*callback)(user, &h, cp);
184			if (++n >= cnt && cnt >= 0) {
185				p->cc = ep - bp;
186				p->bp = bp;
187				return (n);
188			}
189		}
190	}
191	p->cc = 0;
192	return (n);
193}
194
195static int
196pcap_inject_nit(pcap_t *p, const void *buf, size_t size)
197{
198	struct sockaddr sa;
199	int ret;
200
201	memset(&sa, 0, sizeof(sa));
202	strncpy(sa.sa_data, device, sizeof(sa.sa_data));
203	ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
204	if (ret == -1) {
205		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
206		    pcap_strerror(errno));
207		return (-1);
208	}
209	return (ret);
210}
211
212static int
213nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
214{
215	struct nit_ioc nioc;
216
217	memset(&nioc, 0, sizeof(nioc));
218	nioc.nioc_bufspace = BUFSPACE;
219	nioc.nioc_chunksize = CHUNKSIZE;
220	nioc.nioc_typetomatch = NT_ALLTYPES;
221	nioc.nioc_snaplen = p->snapshot;
222	nioc.nioc_bufalign = sizeof(int);
223	nioc.nioc_bufoffset = 0;
224
225	if (to_ms != 0) {
226		nioc.nioc_flags |= NF_TIMEOUT;
227		nioc.nioc_timeout.tv_sec = to_ms / 1000;
228		nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
229	}
230	if (promisc)
231		nioc.nioc_flags |= NF_PROMISC;
232
233	if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
234		snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
235		    pcap_strerror(errno));
236		return (-1);
237	}
238	return (0);
239}
240
241static void
242pcap_close_nit(pcap_t *p)
243{
244	pcap_close_common(p);
245	if (p->device != NULL)
246		free(p->device);
247}
248
249pcap_t *
250pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
251    char *ebuf)
252{
253	int fd;
254	struct sockaddr_nit snit;
255	register pcap_t *p;
256
257	p = (pcap_t *)malloc(sizeof(*p));
258	if (p == NULL) {
259		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
260		return (NULL);
261	}
262
263	if (snaplen < 96)
264		/*
265		 * NIT requires a snapshot length of at least 96.
266		 */
267		snaplen = 96;
268
269	memset(p, 0, sizeof(*p));
270	p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
271	if (fd < 0) {
272		snprintf(ebuf, PCAP_ERRBUF_SIZE,
273		    "socket: %s", pcap_strerror(errno));
274		goto bad;
275	}
276	snit.snit_family = AF_NIT;
277	(void)strncpy(snit.snit_ifname, device, NITIFSIZ);
278
279	if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
280		snprintf(ebuf, PCAP_ERRBUF_SIZE,
281		    "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
282		goto bad;
283	}
284	p->snapshot = snaplen;
285	nit_setflags(p->fd, promisc, to_ms, ebuf);
286
287	/*
288	 * NIT supports only ethernets.
289	 */
290	p->linktype = DLT_EN10MB;
291
292	p->bufsize = BUFSPACE;
293	p->buffer = (u_char *)malloc(p->bufsize);
294	if (p->buffer == NULL) {
295		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
296		goto bad;
297	}
298
299	/*
300	 * We need the device name in order to send packets.
301	 */
302	p->device = strdup(device);
303	if (p->device == NULL) {
304		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
305		free(p->buffer);
306		goto bad;
307	}
308
309	/*
310	 * "p->fd" is a socket, so "select()" should work on it.
311	 */
312	p->selectable_fd = p->fd;
313
314	/*
315	 * This is (presumably) a real Ethernet capture; give it a
316	 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
317	 * that an application can let you choose it, in case you're
318	 * capturing DOCSIS traffic that a Cisco Cable Modem
319	 * Termination System is putting out onto an Ethernet (it
320	 * doesn't put an Ethernet header onto the wire, it puts raw
321	 * DOCSIS frames out on the wire inside the low-level
322	 * Ethernet framing).
323	 */
324	p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
325	/*
326	 * If that fails, just leave the list empty.
327	 */
328	if (p->dlt_list != NULL) {
329		p->dlt_list[0] = DLT_EN10MB;
330		p->dlt_list[1] = DLT_DOCSIS;
331		p->dlt_count = 2;
332	}
333
334	p->read_op = pcap_read_nit;
335	p->inject_op = pcap_inject_nit;
336	p->setfilter_op = install_bpf_program;	/* no kernel filtering */
337	p->set_datalink_op = NULL;	/* can't change data link type */
338	p->getnonblock_op = pcap_getnonblock_fd;
339	p->setnonblock_op = pcap_setnonblock_fd;
340	p->stats_op = pcap_stats_nit;
341	p->close_op = pcap_close_nit;
342
343	return (p);
344 bad:
345	if (fd >= 0)
346		close(fd);
347	free(p);
348	return (NULL);
349}
350
351int
352pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
353{
354	return (0);
355}
356