xref: /freebsd/contrib/libpcap/pcap-snit.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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
27 static const char rcsid[] _U_ =
28     "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.72.2.1 2005/05/03 18:54:38 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 */
85 static int nit_setflags(int, int, int, char *);
86 
87 static int
88 pcap_stats_snit(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 
112 static int
113 pcap_read_snit(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 		/*
145 		 * Has "pcap_breakloop()" been called?
146 		 * If so, return immediately - if we haven't read any
147 		 * packets, clear the flag and return -2 to indicate
148 		 * that we were told to break out of the loop, otherwise
149 		 * leave the flag set, so that the *next* call will break
150 		 * out of the loop without having read any packets, and
151 		 * return the number of packets we've processed so far.
152 		 */
153 		if (p->break_loop) {
154 			if (n == 0) {
155 				p->break_loop = 0;
156 				return (-2);
157 			} else {
158 				p->bp = bp;
159 				p->cc = ep - bp;
160 				return (n);
161 			}
162 		}
163 
164 		++p->md.stat.ps_recv;
165 		cp = bp;
166 
167 		/* get past NIT buffer  */
168 		hdrp = (struct nit_bufhdr *)cp;
169 		cp += sizeof(*hdrp);
170 
171 		/* get past NIT timer   */
172 		ntp = (struct nit_iftime *)cp;
173 		cp += sizeof(*ntp);
174 
175 		ndp = (struct nit_ifdrops *)cp;
176 		p->md.stat.ps_drop = ndp->nh_drops;
177 		cp += sizeof *ndp;
178 
179 		/* get past packet len  */
180 		nlp = (struct nit_iflen *)cp;
181 		cp += sizeof(*nlp);
182 
183 		/* next snapshot        */
184 		bp += hdrp->nhb_totlen;
185 
186 		caplen = nlp->nh_pktlen;
187 		if (caplen > p->snapshot)
188 			caplen = p->snapshot;
189 
190 		if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) {
191 			struct pcap_pkthdr h;
192 			h.ts = ntp->nh_timestamp;
193 			h.len = nlp->nh_pktlen;
194 			h.caplen = caplen;
195 			(*callback)(user, &h, cp);
196 			if (++n >= cnt && cnt >= 0) {
197 				p->cc = ep - bp;
198 				p->bp = bp;
199 				return (n);
200 			}
201 		}
202 	}
203 	p->cc = 0;
204 	return (n);
205 }
206 
207 static int
208 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
209 {
210 	struct strbuf ctl, data;
211 
212 	/*
213 	 * XXX - can we just do
214 	 *
215 	ret = write(pd->f, buf, size);
216 	 */
217 	ctl.len = sizeof(*sa);	/* XXX - what was this? */
218 	ctl.buf = (char *)sa;
219 	data.buf = buf;
220 	data.len = size;
221 	ret = putmsg(p->fd, &ctl, &data);
222 	if (ret == -1) {
223 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
224 		    pcap_strerror(errno));
225 		return (-1);
226 	}
227 	return (ret);
228 }
229 
230 static int
231 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
232 {
233 	bpf_u_int32 flags;
234 	struct strioctl si;
235 	struct timeval timeout;
236 
237 	si.ic_timout = INFTIM;
238 	if (to_ms != 0) {
239 		timeout.tv_sec = to_ms / 1000;
240 		timeout.tv_usec = (to_ms * 1000) % 1000000;
241 		si.ic_cmd = NIOCSTIME;
242 		si.ic_len = sizeof(timeout);
243 		si.ic_dp = (char *)&timeout;
244 		if (ioctl(fd, I_STR, (char *)&si) < 0) {
245 			snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
246 			    pcap_strerror(errno));
247 			return (-1);
248 		}
249 	}
250 	flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
251 	if (promisc)
252 		flags |= NI_PROMISC;
253 	si.ic_cmd = NIOCSFLAGS;
254 	si.ic_len = sizeof(flags);
255 	si.ic_dp = (char *)&flags;
256 	if (ioctl(fd, I_STR, (char *)&si) < 0) {
257 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
258 		    pcap_strerror(errno));
259 		return (-1);
260 	}
261 	return (0);
262 }
263 
264 pcap_t *
265 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
266     char *ebuf)
267 {
268 	struct strioctl si;		/* struct for ioctl() */
269 	struct ifreq ifr;		/* interface request struct */
270 	int chunksize = CHUNKSIZE;
271 	int fd;
272 	static char dev[] = "/dev/nit";
273 	register pcap_t *p;
274 
275 	p = (pcap_t *)malloc(sizeof(*p));
276 	if (p == NULL) {
277 		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
278 		return (NULL);
279 	}
280 
281 	if (snaplen < 96)
282 		/*
283 		 * NIT requires a snapshot length of at least 96.
284 		 */
285 		snaplen = 96;
286 
287 	memset(p, 0, sizeof(*p));
288 	/*
289 	 * Initially try a read/write open (to allow the inject
290 	 * method to work).  If that fails due to permission
291 	 * issues, fall back to read-only.  This allows a
292 	 * non-root user to be granted specific access to pcap
293 	 * capabilities via file permissions.
294 	 *
295 	 * XXX - we should have an API that has a flag that
296 	 * controls whether to open read-only or read-write,
297 	 * so that denial of permission to send (or inability
298 	 * to send, if sending packets isn't supported on
299 	 * the device in question) can be indicated at open
300 	 * time.
301 	 */
302 	p->fd = fd = open(dev, O_RDWR);
303 	if (fd < 0 && errno == EACCES)
304 		p->fd = fd = open(dev, O_RDONLY);
305 	if (fd < 0) {
306 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
307 		    pcap_strerror(errno));
308 		goto bad;
309 	}
310 
311 	/* arrange to get discrete messages from the STREAM and use NIT_BUF */
312 	if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
313 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
314 		    pcap_strerror(errno));
315 		goto bad;
316 	}
317 	if (ioctl(fd, I_PUSH, "nbuf") < 0) {
318 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
319 		    pcap_strerror(errno));
320 		goto bad;
321 	}
322 	/* set the chunksize */
323 	si.ic_cmd = NIOCSCHUNK;
324 	si.ic_timout = INFTIM;
325 	si.ic_len = sizeof(chunksize);
326 	si.ic_dp = (char *)&chunksize;
327 	if (ioctl(fd, I_STR, (char *)&si) < 0) {
328 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
329 		    pcap_strerror(errno));
330 		goto bad;
331 	}
332 
333 	/* request the interface */
334 	strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
335 	ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
336 	si.ic_cmd = NIOCBIND;
337 	si.ic_len = sizeof(ifr);
338 	si.ic_dp = (char *)&ifr;
339 	if (ioctl(fd, I_STR, (char *)&si) < 0) {
340 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
341 			ifr.ifr_name, pcap_strerror(errno));
342 		goto bad;
343 	}
344 
345 	/* set the snapshot length */
346 	si.ic_cmd = NIOCSSNAP;
347 	si.ic_len = sizeof(snaplen);
348 	si.ic_dp = (char *)&snaplen;
349 	if (ioctl(fd, I_STR, (char *)&si) < 0) {
350 		snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
351 		    pcap_strerror(errno));
352 		goto bad;
353 	}
354 	p->snapshot = snaplen;
355 	if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0)
356 		goto bad;
357 
358 	(void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
359 	/*
360 	 * NIT supports only ethernets.
361 	 */
362 	p->linktype = DLT_EN10MB;
363 
364 	p->bufsize = BUFSPACE;
365 	p->buffer = (u_char *)malloc(p->bufsize);
366 	if (p->buffer == NULL) {
367 		strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
368 		goto bad;
369 	}
370 
371 	/*
372 	 * "p->fd" is an FD for a STREAMS device, so "select()" and
373 	 * "poll()" should work on it.
374 	 */
375 	p->selectable_fd = p->fd;
376 
377 	/*
378 	 * This is (presumably) a real Ethernet capture; give it a
379 	 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
380 	 * that an application can let you choose it, in case you're
381 	 * capturing DOCSIS traffic that a Cisco Cable Modem
382 	 * Termination System is putting out onto an Ethernet (it
383 	 * doesn't put an Ethernet header onto the wire, it puts raw
384 	 * DOCSIS frames out on the wire inside the low-level
385 	 * Ethernet framing).
386 	 */
387 	p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
388 	/*
389 	 * If that fails, just leave the list empty.
390 	 */
391 	if (p->dlt_list != NULL) {
392 		p->dlt_list[0] = DLT_EN10MB;
393 		p->dlt_list[1] = DLT_DOCSIS;
394 		p->dlt_count = 2;
395 	}
396 
397 	p->read_op = pcap_read_snit;
398 	p->inject_op = pcap_inject_snit;
399 	p->setfilter_op = install_bpf_program;	/* no kernel filtering */
400 	p->setdirection_op = NULL;	/* Not implemented. */
401 	p->set_datalink_op = NULL;	/* can't change data link type */
402 	p->getnonblock_op = pcap_getnonblock_fd;
403 	p->setnonblock_op = pcap_setnonblock_fd;
404 	p->stats_op = pcap_stats_snit;
405 	p->close_op = pcap_close_common;
406 
407 	return (p);
408  bad:
409 	if (fd >= 0)
410 		close(fd);
411 	free(p);
412 	return (NULL);
413 }
414 
415 int
416 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
417 {
418 	return (0);
419 }
420