pcap-snit.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 * Modifications made to accommodate the new SunOS4.0 NIT facility by
22 * Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
23 * This module now handles the STREAMS based NIT.
24 */
25
26#ifndef lint
27static const char rcsid[] =
28    "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.56 2001/12/10 07:14:20 guy Exp $ (LBL)";
29#endif
30
31#ifdef HAVE_CONFIG_H
32#include "config.h"
33#endif
34
35#include <sys/types.h>
36#include <sys/time.h>
37#include <sys/timeb.h>
38#include <sys/dir.h>
39#include <sys/fcntlcom.h>
40#include <sys/file.h>
41#include <sys/ioctl.h>
42#include <sys/socket.h>
43#include <sys/stropts.h>
44
45#include <net/if.h>
46#include <net/nit.h>
47#include <net/nit_if.h>
48#include <net/nit_pf.h>
49#include <net/nit_buf.h>
50
51#include <netinet/in.h>
52#include <netinet/in_systm.h>
53#include <netinet/ip.h>
54#include <netinet/if_ether.h>
55#include <netinet/ip_var.h>
56#include <netinet/udp.h>
57#include <netinet/udp_var.h>
58#include <netinet/tcp.h>
59#include <netinet/tcpip.h>
60
61#include <ctype.h>
62#include <errno.h>
63#include <stdio.h>
64#include <string.h>
65#include <unistd.h>
66
67#include "pcap-int.h"
68
69#ifdef HAVE_OS_PROTO_H
70#include "os-proto.h"
71#endif
72
73/*
74 * The chunk size for NIT.  This is the amount of buffering
75 * done for read calls.
76 */
77#define CHUNKSIZE (2*1024)
78
79/*
80 * The total buffer space used by NIT.
81 */
82#define BUFSPACE (4*CHUNKSIZE)
83
84/* Forwards */
85static int nit_setflags(int, int, int, char *);
86
87int
88pcap_stats(pcap_t *p, struct pcap_stat *ps)
89{
90
91	/*
92	 * "ps_recv" counts packets handed to the filter, not packets
93	 * that passed the filter.  As filtering is done in userland,
94	 * this does not include packets dropped because we ran out
95	 * of buffer space.
96	 *
97	 * "ps_drop" counts packets dropped inside the "/dev/nit"
98	 * device because of flow control requirements or resource
99	 * exhaustion; it doesn't count packets dropped by the
100	 * interface driver, or packets dropped upstream.  As filtering
101	 * is done in userland, it counts packets regardless of whether
102	 * they would've passed the filter.
103	 *
104	 * These statistics don't include packets not yet read from the
105	 * kernel by libpcap or packets not yet read from libpcap by the
106	 * application.
107	 */
108	*ps = p->md.stat;
109	return (0);
110}
111
112int
113pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
114{
115	register int cc, n;
116	register struct bpf_insn *fcode = p->fcode.bf_insns;
117	register u_char *bp, *cp, *ep;
118	register struct nit_bufhdr *hdrp;
119	register struct nit_iftime *ntp;
120	register struct nit_iflen *nlp;
121	register struct nit_ifdrops *ndp;
122	register int caplen;
123
124	cc = p->cc;
125	if (cc == 0) {
126		cc = read(p->fd, (char *)p->buffer, p->bufsize);
127		if (cc < 0) {
128			if (errno == EWOULDBLOCK)
129				return (0);
130			snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
131				pcap_strerror(errno));
132			return (-1);
133		}
134		bp = p->buffer;
135	} else
136		bp = p->bp;
137
138	/*
139	 * loop through each snapshot in the chunk
140	 */
141	n = 0;
142	ep = bp + cc;
143	while (bp < ep) {
144		++p->md.stat.ps_recv;
145		cp = bp;
146
147		/* get past NIT buffer  */
148		hdrp = (struct nit_bufhdr *)cp;
149		cp += sizeof(*hdrp);
150
151		/* get past NIT timer   */
152		ntp = (struct nit_iftime *)cp;
153		cp += sizeof(*ntp);
154
155		ndp = (struct nit_ifdrops *)cp;
156		p->md.stat.ps_drop = ndp->nh_drops;
157		cp += sizeof *ndp;
158
159		/* get past packet len  */
160		nlp = (struct nit_iflen *)cp;
161		cp += sizeof(*nlp);
162
163		/* next snapshot        */
164		bp += hdrp->nhb_totlen;
165
166		caplen = nlp->nh_pktlen;
167		if (caplen > p->snapshot)
168			caplen = p->snapshot;
169
170		if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) {
171			struct pcap_pkthdr h;
172			h.ts = ntp->nh_timestamp;
173			h.len = nlp->nh_pktlen;
174			h.caplen = caplen;
175			(*callback)(user, &h, cp);
176			if (++n >= cnt && cnt >= 0) {
177				p->cc = ep - bp;
178				p->bp = bp;
179				return (n);
180			}
181		}
182	}
183	p->cc = 0;
184	return (n);
185}
186
187static int
188nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
189{
190	bpf_u_int32 flags;
191	struct strioctl si;
192	struct timeval timeout;
193
194	si.ic_timout = INFTIM;
195	if (to_ms != 0) {
196		timeout.tv_sec = to_ms / 1000;
197		timeout.tv_usec = (to_ms * 1000) % 1000000;
198		si.ic_cmd = NIOCSTIME;
199		si.ic_len = sizeof(timeout);
200		si.ic_dp = (char *)&timeout;
201		if (ioctl(fd, I_STR, (char *)&si) < 0) {
202			snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
203			    pcap_strerror(errno));
204			return (-1);
205		}
206	}
207	flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
208	if (promisc)
209		flags |= NI_PROMISC;
210	si.ic_cmd = NIOCSFLAGS;
211	si.ic_len = sizeof(flags);
212	si.ic_dp = (char *)&flags;
213	if (ioctl(fd, I_STR, (char *)&si) < 0) {
214		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
215		    pcap_strerror(errno));
216		return (-1);
217	}
218	return (0);
219}
220
221pcap_t *
222pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
223{
224	struct strioctl si;		/* struct for ioctl() */
225	struct ifreq ifr;		/* interface request struct */
226	int chunksize = CHUNKSIZE;
227	int fd;
228	static char dev[] = "/dev/nit";
229	register pcap_t *p;
230
231	p = (pcap_t *)malloc(sizeof(*p));
232	if (p == NULL) {
233		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
234		return (NULL);
235	}
236
237	if (snaplen < 96)
238		/*
239		 * NIT requires a snapshot length of at least 96.
240		 */
241		snaplen = 96;
242
243	memset(p, 0, sizeof(*p));
244	p->fd = fd = open(dev, O_RDONLY);
245	if (fd < 0) {
246		snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
247		    pcap_strerror(errno));
248		goto bad;
249	}
250
251	/* arrange to get discrete messages from the STREAM and use NIT_BUF */
252	if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
253		snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
254		    pcap_strerror(errno));
255		goto bad;
256	}
257	if (ioctl(fd, I_PUSH, "nbuf") < 0) {
258		snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
259		    pcap_strerror(errno));
260		goto bad;
261	}
262	/* set the chunksize */
263	si.ic_cmd = NIOCSCHUNK;
264	si.ic_timout = INFTIM;
265	si.ic_len = sizeof(chunksize);
266	si.ic_dp = (char *)&chunksize;
267	if (ioctl(fd, I_STR, (char *)&si) < 0) {
268		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
269		    pcap_strerror(errno));
270		goto bad;
271	}
272
273	/* request the interface */
274	strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
275	ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = ' ';
276	si.ic_cmd = NIOCBIND;
277	si.ic_len = sizeof(ifr);
278	si.ic_dp = (char *)&ifr;
279	if (ioctl(fd, I_STR, (char *)&si) < 0) {
280		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
281			ifr.ifr_name, pcap_strerror(errno));
282		goto bad;
283	}
284
285	/* set the snapshot length */
286	si.ic_cmd = NIOCSSNAP;
287	si.ic_len = sizeof(snaplen);
288	si.ic_dp = (char *)&snaplen;
289	if (ioctl(fd, I_STR, (char *)&si) < 0) {
290		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
291		    pcap_strerror(errno));
292		goto bad;
293	}
294	p->snapshot = snaplen;
295	if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0)
296		goto bad;
297
298	(void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
299	/*
300	 * NIT supports only ethernets.
301	 */
302	p->linktype = DLT_EN10MB;
303
304	p->bufsize = BUFSPACE;
305	p->buffer = (u_char *)malloc(p->bufsize);
306	if (p->buffer == NULL) {
307		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
308		goto bad;
309	}
310	return (p);
311 bad:
312	if (fd >= 0)
313		close(fd);
314	free(p);
315	return (NULL);
316}
317
318int
319pcap_setfilter(pcap_t *p, struct bpf_program *fp)
320{
321
322	if (install_bpf_program(p, fp) < 0)
323		return (-1);
324	return (0);
325}
326