1 /*
2 * Copyright (c) 1993, 1994, 1995, 1996, 1997
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-snoop.c,v 1.54.2.1 2005/05/03 18:54:38 guy Exp $ (LBL)";
24 #endif
25
26 #ifdef HAVE_CONFIG_H
27 #include "config.h"
28 #endif
29
30 #include <sys/param.h>
31 #include <sys/file.h>
32 #include <sys/ioctl.h>
33 #include <sys/socket.h>
34 #include <sys/time.h>
35
36 #include <net/raw.h>
37 #include <net/if.h>
38
39 #include <netinet/in.h>
40 #include <netinet/in_systm.h>
41 #include <netinet/ip.h>
42 #include <netinet/if_ether.h>
43 #include <netinet/ip_var.h>
44 #include <netinet/udp.h>
45 #include <netinet/udp_var.h>
46 #include <netinet/tcp.h>
47 #include <netinet/tcpip.h>
48
49 #include <errno.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54
55 #include "pcap-int.h"
56
57 #ifdef HAVE_OS_PROTO_H
58 #include "os-proto.h"
59 #endif
60
61 static int
pcap_read_snoop(pcap_t * p,int cnt,pcap_handler callback,u_char * user)62 pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
63 {
64 int cc;
65 register struct snoopheader *sh;
66 register u_int datalen;
67 register u_int caplen;
68 register u_char *cp;
69
70 again:
71 /*
72 * Has "pcap_breakloop()" been called?
73 */
74 if (p->break_loop) {
75 /*
76 * Yes - clear the flag that indicates that it
77 * has, and return -2 to indicate that we were
78 * told to break out of the loop.
79 */
80 p->break_loop = 0;
81 return (-2);
82 }
83 cc = read(p->fd, (char *)p->buffer, p->bufsize);
84 if (cc < 0) {
85 /* Don't choke when we get ptraced */
86 switch (errno) {
87
88 case EINTR:
89 goto again;
90
91 case EWOULDBLOCK:
92 return (0); /* XXX */
93 }
94 snprintf(p->errbuf, sizeof(p->errbuf),
95 "read: %s", pcap_strerror(errno));
96 return (-1);
97 }
98 sh = (struct snoopheader *)p->buffer;
99 datalen = sh->snoop_packetlen;
100
101 /*
102 * XXX - Sigh, snoop_packetlen is a 16 bit quantity. If we
103 * got a short length, but read a full sized snoop pakcet,
104 * assume we overflowed and add back the 64K...
105 */
106 if (cc == (p->snapshot + sizeof(struct snoopheader)) &&
107 (datalen < p->snapshot))
108 datalen += (64 * 1024);
109
110 caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
111 cp = (u_char *)(sh + 1) + p->offset; /* XXX */
112
113 /*
114 * XXX unfortunately snoop loopback isn't exactly like
115 * BSD's. The address family is encoded in the first 2
116 * bytes rather than the first 4 bytes! Luckily the last
117 * two snoop loopback bytes are zeroed.
118 */
119 if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) {
120 u_int *uip = (u_int *)cp;
121 *uip >>= 16;
122 }
123
124 if (p->fcode.bf_insns == NULL ||
125 bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
126 struct pcap_pkthdr h;
127 ++p->md.stat.ps_recv;
128 h.ts.tv_sec = sh->snoop_timestamp.tv_sec;
129 h.ts.tv_usec = sh->snoop_timestamp.tv_usec;
130 h.len = datalen;
131 h.caplen = caplen;
132 (*callback)(user, &h, cp);
133 return (1);
134 }
135 return (0);
136 }
137
138 static int
pcap_inject_snoop(pcap_t * p,const void * buf,size_t size)139 pcap_inject_snoop(pcap_t *p, const void *buf, size_t size)
140 {
141 int ret;
142
143 /*
144 * XXX - libnet overwrites the source address with what I
145 * presume is the interface's address; is that required?
146 */
147 ret = write(p->fd, buf, size);
148 if (ret == -1) {
149 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
150 pcap_strerror(errno));
151 return (-1);
152 }
153 return (ret);
154 }
155
156 static int
pcap_stats_snoop(pcap_t * p,struct pcap_stat * ps)157 pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps)
158 {
159 register struct rawstats *rs;
160 struct rawstats rawstats;
161
162 rs = &rawstats;
163 memset(rs, 0, sizeof(*rs));
164 if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
165 snprintf(p->errbuf, sizeof(p->errbuf),
166 "SIOCRAWSTATS: %s", pcap_strerror(errno));
167 return (-1);
168 }
169
170 /*
171 * "ifdrops" are those dropped by the network interface
172 * due to resource shortages or hardware errors.
173 *
174 * "sbdrops" are those dropped due to socket buffer limits.
175 *
176 * As filter is done in userland, "sbdrops" counts packets
177 * regardless of whether they would've passed the filter.
178 *
179 * XXX - does this count *all* Snoop or Drain sockets,
180 * rather than just this socket? If not, why does it have
181 * both Snoop and Drain statistics?
182 */
183 p->md.stat.ps_drop =
184 rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
185 rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
186
187 /*
188 * "ps_recv" counts only packets that passed the filter.
189 * As filtering is done in userland, this does not include
190 * packets dropped because we ran out of buffer space.
191 */
192 *ps = p->md.stat;
193 return (0);
194 }
195
196 /* XXX can't disable promiscuous */
197 pcap_t *
pcap_open_live(const char * device,int snaplen,int promisc,int to_ms,char * ebuf)198 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
199 char *ebuf)
200 {
201 int fd;
202 struct sockaddr_raw sr;
203 struct snoopfilter sf;
204 u_int v;
205 int ll_hdrlen;
206 int snooplen;
207 pcap_t *p;
208 struct ifreq ifr;
209
210 p = (pcap_t *)malloc(sizeof(*p));
211 if (p == NULL) {
212 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
213 pcap_strerror(errno));
214 return (NULL);
215 }
216 memset(p, 0, sizeof(*p));
217 fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
218 if (fd < 0) {
219 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
220 pcap_strerror(errno));
221 goto bad;
222 }
223 p->fd = fd;
224 memset(&sr, 0, sizeof(sr));
225 sr.sr_family = AF_RAW;
226 (void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
227 if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
228 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
229 pcap_strerror(errno));
230 goto bad;
231 }
232 memset(&sf, 0, sizeof(sf));
233 if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
234 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
235 pcap_strerror(errno));
236 goto bad;
237 }
238 v = 64 * 1024;
239 (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
240 /*
241 * XXX hack - map device name to link layer type
242 */
243 if (strncmp("et", device, 2) == 0 || /* Challenge 10 Mbit */
244 strncmp("ec", device, 2) == 0 || /* Indigo/Indy 10 Mbit,
245 O2 10/100 */
246 strncmp("ef", device, 2) == 0 || /* O200/2000 10/100 Mbit */
247 strncmp("eg", device, 2) == 0 || /* Octane/O2xxx/O3xxx Gigabit */
248 strncmp("gfe", device, 3) == 0 || /* GIO 100 Mbit */
249 strncmp("fxp", device, 3) == 0 || /* Challenge VME Enet */
250 strncmp("ep", device, 2) == 0 || /* Challenge 8x10 Mbit EPLEX */
251 strncmp("vfe", device, 3) == 0 || /* Challenge VME 100Mbit */
252 strncmp("fa", device, 2) == 0 ||
253 strncmp("qaa", device, 3) == 0 ||
254 strncmp("cip", device, 3) == 0 ||
255 strncmp("el", device, 2) == 0) {
256 p->linktype = DLT_EN10MB;
257 p->offset = RAW_HDRPAD(sizeof(struct ether_header));
258 ll_hdrlen = sizeof(struct ether_header);
259 /*
260 * This is (presumably) a real Ethernet capture; give it a
261 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
262 * that an application can let you choose it, in case you're
263 * capturing DOCSIS traffic that a Cisco Cable Modem
264 * Termination System is putting out onto an Ethernet (it
265 * doesn't put an Ethernet header onto the wire, it puts raw
266 * DOCSIS frames out on the wire inside the low-level
267 * Ethernet framing).
268 *
269 * XXX - are there any sorts of "fake Ethernet" that have
270 * Ethernet link-layer headers but that *shouldn't offer
271 * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it
272 * or get traffic bridged onto it? "el" is for ATM LANE
273 * Ethernet devices, so that might be the case for them;
274 * the same applies for "qaa" classical IP devices. If
275 * "fa" devices are for FORE SPANS, that'd apply to them
276 * as well; what are "cip" devices - some other ATM
277 * Classical IP devices?
278 */
279 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
280 /*
281 * If that fails, just leave the list empty.
282 */
283 if (p->dlt_list != NULL) {
284 p->dlt_list[0] = DLT_EN10MB;
285 p->dlt_list[1] = DLT_DOCSIS;
286 p->dlt_count = 2;
287 }
288 } else if (strncmp("ipg", device, 3) == 0 ||
289 strncmp("rns", device, 3) == 0 || /* O2/200/2000 FDDI */
290 strncmp("xpi", device, 3) == 0) {
291 p->linktype = DLT_FDDI;
292 p->offset = 3; /* XXX yeah? */
293 ll_hdrlen = 13;
294 } else if (strncmp("ppp", device, 3) == 0) {
295 p->linktype = DLT_RAW;
296 ll_hdrlen = 0; /* DLT_RAW meaning "no PPP header, just the IP packet"? */
297 } else if (strncmp("qfa", device, 3) == 0) {
298 p->linktype = DLT_IP_OVER_FC;
299 ll_hdrlen = 24;
300 } else if (strncmp("pl", device, 2) == 0) {
301 p->linktype = DLT_RAW;
302 ll_hdrlen = 0; /* Cray UNICOS/mp pseudo link */
303 } else if (strncmp("lo", device, 2) == 0) {
304 p->linktype = DLT_NULL;
305 ll_hdrlen = 4;
306 } else {
307 snprintf(ebuf, PCAP_ERRBUF_SIZE,
308 "snoop: unknown physical layer type");
309 goto bad;
310 }
311 #ifdef SIOCGIFMTU
312 /*
313 * XXX - IRIX appears to give you an error if you try to set the
314 * capture length to be greater than the MTU, so let's try to get
315 * the MTU first and, if that succeeds, trim the snap length
316 * to be no greater than the MTU.
317 */
318 (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
319 if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
320 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
321 pcap_strerror(errno));
322 goto bad;
323 }
324 /*
325 * OK, we got it.
326 *
327 * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
328 * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
329 * structure, others don't.
330 *
331 * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
332 * we define it as "ifr_metric", as using that field appears to
333 * work on the versions that lack "ifr_mtu" (and, on those that
334 * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
335 * members of the "ifr_ifru" union, which suggests that they
336 * may be interchangeable in this case).
337 */
338 #ifndef ifr_mtu
339 #define ifr_mtu ifr_metric
340 #endif
341 if (snaplen > ifr.ifr_mtu + ll_hdrlen)
342 snaplen = ifr.ifr_mtu + ll_hdrlen;
343 #endif
344
345 /*
346 * The argument to SIOCSNOOPLEN is the number of link-layer
347 * payload bytes to capture - it doesn't count link-layer
348 * header bytes.
349 */
350 snooplen = snaplen - ll_hdrlen;
351 if (snooplen < 0)
352 snooplen = 0;
353 if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
354 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
355 pcap_strerror(errno));
356 goto bad;
357 }
358 p->snapshot = snaplen;
359 v = 1;
360 if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
361 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
362 pcap_strerror(errno));
363 goto bad;
364 }
365
366 p->bufsize = 4096; /* XXX */
367 p->buffer = (u_char *)malloc(p->bufsize);
368 if (p->buffer == NULL) {
369 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
370 pcap_strerror(errno));
371 goto bad;
372 }
373
374 /*
375 * "p->fd" is a socket, so "select()" should work on it.
376 */
377 p->selectable_fd = p->fd;
378
379 p->read_op = pcap_read_snoop;
380 p->inject_op = pcap_inject_snoop;
381 p->setfilter_op = install_bpf_program; /* no kernel filtering */
382 p->setdirection_op = NULL; /* Not implemented. */
383 p->set_datalink_op = NULL; /* can't change data link type */
384 p->getnonblock_op = pcap_getnonblock_fd;
385 p->setnonblock_op = pcap_setnonblock_fd;
386 p->stats_op = pcap_stats_snoop;
387 p->close_op = pcap_close_common;
388
389 return (p);
390 bad:
391 (void)close(fd);
392 /*
393 * Get rid of any link-layer type list we allocated.
394 */
395 if (p->dlt_list != NULL)
396 free(p->dlt_list);
397 free(p);
398 return (NULL);
399 }
400
401 int
pcap_platform_finddevs(pcap_if_t ** alldevsp,char * errbuf)402 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
403 {
404 return (0);
405 }
406