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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
22 static const char rcsid[] _U_ =
23     "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.57.2.1 2005/05/03 18:54:37 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 */
72 static int nit_setflags(int, int, int, char *);
73 
74 static int
pcap_stats_nit(pcap_t * p,struct pcap_stat * ps)75 pcap_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 
98 static int
pcap_read_nit(pcap_t * p,int cnt,pcap_handler callback,u_char * user)99 pcap_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 
195 static int
pcap_inject_nit(pcap_t * p,const void * buf,size_t size)196 pcap_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 
212 static int
nit_setflags(int fd,int promisc,int to_ms,char * ebuf)213 nit_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 
241 static void
pcap_close_nit(pcap_t * p)242 pcap_close_nit(pcap_t *p)
243 {
244 	pcap_close_common(p);
245 	if (p->device != NULL)
246 		free(p->device);
247 }
248 
249 pcap_t *
pcap_open_live(const char * device,int snaplen,int promisc,int to_ms,char * ebuf)250 pcap_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->setdirection_op = NULL;	/* Not implemented. */
338 	p->set_datalink_op = NULL;	/* can't change data link type */
339 	p->getnonblock_op = pcap_getnonblock_fd;
340 	p->setnonblock_op = pcap_setnonblock_fd;
341 	p->stats_op = pcap_stats_nit;
342 	p->close_op = pcap_close_nit;
343 
344 	return (p);
345  bad:
346 	if (fd >= 0)
347 		close(fd);
348 	free(p);
349 	return (NULL);
350 }
351 
352 int
pcap_platform_finddevs(pcap_if_t ** alldevsp,char * errbuf)353 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
354 {
355 	return (0);
356 }
357