libpcap  1.10.1
About: libpcap is a packet filter library used by tools like tcpdump.
  Fossies Dox: libpcap-1.10.1.tar.gz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

pcap-snoop.c
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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 
22 #ifdef HAVE_CONFIG_H
23 #include <config.h>
24 #endif
25 
26 #include <sys/param.h>
27 #include <sys/file.h>
28 #include <sys/ioctl.h>
29 #include <sys/socket.h>
30 #include <sys/time.h>
31 
32 #include <net/raw.h>
33 #include <net/if.h>
34 
35 #include <netinet/in.h>
36 #include <netinet/in_systm.h>
37 #include <netinet/ip.h>
38 #include <netinet/if_ether.h>
39 #include <netinet/ip_var.h>
40 #include <netinet/udp.h>
41 #include <netinet/udp_var.h>
42 #include <netinet/tcp.h>
43 #include <netinet/tcpip.h>
44 
45 #include <errno.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 
51 #include "pcap-int.h"
52 
53 #ifdef HAVE_OS_PROTO_H
54 #include "os-proto.h"
55 #endif
56 
57 /*
58  * Private data for capturing on snoop devices.
59  */
60 struct pcap_snoop {
61  struct pcap_stat stat;
62 };
63 
64 static int
65 pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
66 {
67  struct pcap_snoop *psn = p->priv;
68  int cc;
69  register struct snoopheader *sh;
70  register u_int datalen;
71  register u_int caplen;
72  register u_char *cp;
73 
74 again:
75  /*
76  * Has "pcap_breakloop()" been called?
77  */
78  if (p->break_loop) {
79  /*
80  * Yes - clear the flag that indicates that it
81  * has, and return -2 to indicate that we were
82  * told to break out of the loop.
83  */
84  p->break_loop = 0;
85  return (-2);
86  }
87  cc = read(p->fd, (char *)p->buffer, p->bufsize);
88  if (cc < 0) {
89  /* Don't choke when we get ptraced */
90  switch (errno) {
91 
92  case EINTR:
93  goto again;
94 
95  case EWOULDBLOCK:
96  return (0); /* XXX */
97  }
99  errno, "read");
100  return (-1);
101  }
102  sh = (struct snoopheader *)p->buffer;
103  datalen = sh->snoop_packetlen;
104 
105  /*
106  * XXX - Sigh, snoop_packetlen is a 16 bit quantity. If we
107  * got a short length, but read a full sized snoop pakcet,
108  * assume we overflowed and add back the 64K...
109  */
110  if (cc == (p->snapshot + sizeof(struct snoopheader)) &&
111  (datalen < p->snapshot))
112  datalen += (64 * 1024);
113 
114  caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
115  cp = (u_char *)(sh + 1) + p->offset; /* XXX */
116 
117  /*
118  * XXX unfortunately snoop loopback isn't exactly like
119  * BSD's. The address family is encoded in the first 2
120  * bytes rather than the first 4 bytes! Luckily the last
121  * two snoop loopback bytes are zeroed.
122  */
123  if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) {
124  u_int *uip = (u_int *)cp;
125  *uip >>= 16;
126  }
127 
128  if (p->fcode.bf_insns == NULL ||
129  pcap_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
130  struct pcap_pkthdr h;
131  ++psn->stat.ps_recv;
132  h.ts.tv_sec = sh->snoop_timestamp.tv_sec;
133  h.ts.tv_usec = sh->snoop_timestamp.tv_usec;
134  h.len = datalen;
135  h.caplen = caplen;
136  (*callback)(user, &h, cp);
137  return (1);
138  }
139  return (0);
140 }
141 
142 static int
143 pcap_inject_snoop(pcap_t *p, const void *buf, int size)
144 {
145  int ret;
146 
147  /*
148  * XXX - libnet overwrites the source address with what I
149  * presume is the interface's address; is that required?
150  */
151  ret = write(p->fd, buf, size);
152  if (ret == -1) {
154  errno, "send");
155  return (-1);
156  }
157  return (ret);
158 }
159 
160 static int
162 {
163  struct pcap_snoop *psn = p->priv;
164  register struct rawstats *rs;
165  struct rawstats rawstats;
166 
167  rs = &rawstats;
168  memset(rs, 0, sizeof(*rs));
169  if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
170  pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
171  errno, "SIOCRAWSTATS");
172  return (-1);
173  }
174 
175  /*
176  * "ifdrops" are those dropped by the network interface
177  * due to resource shortages or hardware errors.
178  *
179  * "sbdrops" are those dropped due to socket buffer limits.
180  *
181  * As filter is done in userland, "sbdrops" counts packets
182  * regardless of whether they would've passed the filter.
183  *
184  * XXX - does this count *all* Snoop or Drain sockets,
185  * rather than just this socket? If not, why does it have
186  * both Snoop and Drain statistics?
187  */
188  psn->stat.ps_drop =
189  rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
190  rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
191 
192  /*
193  * "ps_recv" counts only packets that passed the filter.
194  * As filtering is done in userland, this does not include
195  * packets dropped because we ran out of buffer space.
196  */
197  *ps = psn->stat;
198  return (0);
199 }
200 
201 /* XXX can't disable promiscuous */
202 static int
204 {
205  int fd;
206  struct sockaddr_raw sr;
207  struct snoopfilter sf;
208  u_int v;
209  int ll_hdrlen;
210  int snooplen;
211  struct ifreq ifr;
212 
213  fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
214  if (fd < 0) {
216  errno, "snoop socket");
217  goto bad;
218  }
219  p->fd = fd;
220  memset(&sr, 0, sizeof(sr));
221  sr.sr_family = AF_RAW;
222  (void)strncpy(sr.sr_ifname, p->opt.device, sizeof(sr.sr_ifname));
223  if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
224  /*
225  * XXX - there's probably a particular bind error that
226  * means "there's no such device" and a particular bind
227  * error that means "that device doesn't support snoop";
228  * they might be the same error, if they both end up
229  * meaning "snoop doesn't know about that device".
230  */
232  errno, "snoop bind");
233  goto bad;
234  }
235  memset(&sf, 0, sizeof(sf));
236  if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
238  errno, "SIOCADDSNOOP");
239  goto bad;
240  }
241  if (p->opt.buffer_size != 0)
242  v = p->opt.buffer_size;
243  else
244  v = 64 * 1024; /* default to 64K buffer size */
245  (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
246  /*
247  * XXX hack - map device name to link layer type
248  */
249  if (strncmp("et", p->opt.device, 2) == 0 || /* Challenge 10 Mbit */
250  strncmp("ec", p->opt.device, 2) == 0 || /* Indigo/Indy 10 Mbit,
251  O2 10/100 */
252  strncmp("ef", p->opt.device, 2) == 0 || /* O200/2000 10/100 Mbit */
253  strncmp("eg", p->opt.device, 2) == 0 || /* Octane/O2xxx/O3xxx Gigabit */
254  strncmp("gfe", p->opt.device, 3) == 0 || /* GIO 100 Mbit */
255  strncmp("fxp", p->opt.device, 3) == 0 || /* Challenge VME Enet */
256  strncmp("ep", p->opt.device, 2) == 0 || /* Challenge 8x10 Mbit EPLEX */
257  strncmp("vfe", p->opt.device, 3) == 0 || /* Challenge VME 100Mbit */
258  strncmp("fa", p->opt.device, 2) == 0 ||
259  strncmp("qaa", p->opt.device, 3) == 0 ||
260  strncmp("cip", p->opt.device, 3) == 0 ||
261  strncmp("el", p->opt.device, 2) == 0) {
262  p->linktype = DLT_EN10MB;
263  p->offset = RAW_HDRPAD(sizeof(struct ether_header));
264  ll_hdrlen = sizeof(struct ether_header);
265  /*
266  * This is (presumably) a real Ethernet capture; give it a
267  * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
268  * that an application can let you choose it, in case you're
269  * capturing DOCSIS traffic that a Cisco Cable Modem
270  * Termination System is putting out onto an Ethernet (it
271  * doesn't put an Ethernet header onto the wire, it puts raw
272  * DOCSIS frames out on the wire inside the low-level
273  * Ethernet framing).
274  *
275  * XXX - are there any sorts of "fake Ethernet" that have
276  * Ethernet link-layer headers but that *shouldn't offer
277  * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it
278  * or get traffic bridged onto it? "el" is for ATM LANE
279  * Ethernet devices, so that might be the case for them;
280  * the same applies for "qaa" classical IP devices. If
281  * "fa" devices are for FORE SPANS, that'd apply to them
282  * as well; what are "cip" devices - some other ATM
283  * Classical IP devices?
284  */
285  p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
286  /*
287  * If that fails, just leave the list empty.
288  */
289  if (p->dlt_list != NULL) {
290  p->dlt_list[0] = DLT_EN10MB;
291  p->dlt_list[1] = DLT_DOCSIS;
292  p->dlt_count = 2;
293  }
294  } else if (strncmp("ipg", p->opt.device, 3) == 0 ||
295  strncmp("rns", p->opt.device, 3) == 0 || /* O2/200/2000 FDDI */
296  strncmp("xpi", p->opt.device, 3) == 0) {
297  p->linktype = DLT_FDDI;
298  p->offset = 3; /* XXX yeah? */
299  ll_hdrlen = 13;
300  } else if (strncmp("ppp", p->opt.device, 3) == 0) {
301  p->linktype = DLT_RAW;
302  ll_hdrlen = 0; /* DLT_RAW meaning "no PPP header, just the IP packet"? */
303  } else if (strncmp("qfa", p->opt.device, 3) == 0) {
305  ll_hdrlen = 24;
306  } else if (strncmp("pl", p->opt.device, 2) == 0) {
307  p->linktype = DLT_RAW;
308  ll_hdrlen = 0; /* Cray UNICOS/mp pseudo link */
309  } else if (strncmp("lo", p->opt.device, 2) == 0) {
310  p->linktype = DLT_NULL;
311  ll_hdrlen = 4;
312  } else {
314  "snoop: unknown physical layer type");
315  goto bad;
316  }
317 
318  if (p->opt.rfmon) {
319  /*
320  * No monitor mode on Irix (no Wi-Fi devices on
321  * hardware supported by Irix).
322  */
323  return (PCAP_ERROR_RFMON_NOTSUP);
324  }
325 
326  /*
327  * Turn a negative snapshot value (invalid), a snapshot value of
328  * 0 (unspecified), or a value bigger than the normal maximum
329  * value, into the maximum allowed value.
330  *
331  * If some application really *needs* a bigger snapshot
332  * length, we should just increase MAXIMUM_SNAPLEN.
333  */
334  if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
336 
337 #ifdef SIOCGIFMTU
338  /*
339  * XXX - IRIX appears to give you an error if you try to set the
340  * capture length to be greater than the MTU, so let's try to get
341  * the MTU first and, if that succeeds, trim the snap length
342  * to be no greater than the MTU.
343  */
344  (void)strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
345  if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
347  errno, "SIOCGIFMTU");
348  goto bad;
349  }
350  /*
351  * OK, we got it.
352  *
353  * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
354  * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
355  * structure, others don't.
356  *
357  * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
358  * we define it as "ifr_metric", as using that field appears to
359  * work on the versions that lack "ifr_mtu" (and, on those that
360  * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
361  * members of the "ifr_ifru" union, which suggests that they
362  * may be interchangeable in this case).
363  */
364 #ifndef ifr_mtu
365 #define ifr_mtu ifr_metric
366 #endif
367  if (p->snapshot > ifr.ifr_mtu + ll_hdrlen)
368  p->snapshot = ifr.ifr_mtu + ll_hdrlen;
369 #endif
370 
371  /*
372  * The argument to SIOCSNOOPLEN is the number of link-layer
373  * payload bytes to capture - it doesn't count link-layer
374  * header bytes.
375  */
376  snooplen = p->snapshot - ll_hdrlen;
377  if (snooplen < 0)
378  snooplen = 0;
379  if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
381  errno, "SIOCSNOOPLEN");
382  goto bad;
383  }
384  v = 1;
385  if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
387  errno, "SIOCSNOOPING");
388  goto bad;
389  }
390 
391  p->bufsize = 4096; /* XXX */
392  p->buffer = malloc(p->bufsize);
393  if (p->buffer == NULL) {
395  errno, "malloc");
396  goto bad;
397  }
398 
399  /*
400  * "p->fd" is a socket, so "select()" should work on it.
401  */
402  p->selectable_fd = p->fd;
403 
406  p->setfilter_op = install_bpf_program; /* no kernel filtering */
407  p->setdirection_op = NULL; /* Not implemented. */
408  p->set_datalink_op = NULL; /* can't change data link type */
412 
413  return (0);
414  bad:
416  return (PCAP_ERROR);
417 }
418 
419 pcap_t *
420 pcap_create_interface(const char *device _U_, char *ebuf)
421 {
422  pcap_t *p;
423 
424  p = PCAP_CREATE_COMMON(ebuf, struct pcap_snoop);
425  if (p == NULL)
426  return (NULL);
427 
429  return (p);
430 }
431 
432 /*
433  * XXX - there's probably a particular bind error that means "that device
434  * doesn't support snoop"; if so, we should try a bind and use that.
435  */
436 static int
437 can_be_bound(const char *name _U_)
438 {
439  return (1);
440 }
441 
442 static int
443 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
444 {
445  /*
446  * Nothing we can do.
447  * XXX - is there a way to find out whether an adapter has
448  * something plugged into it?
449  */
450  return (0);
451 }
452 
453 int
454 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
455 {
456  return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
457  get_if_flags));
458 }
459 
460 /*
461  * Libpcap version string.
462  */
463 const char *
465 {
466  return (PCAP_VERSION_STRING);
467 }
u_int bpf_u_int32
Definition: bpf.h:98
u_int pcap_filter(const struct bpf_insn *pc, const u_char *p, u_int wirelen, u_int buflen)
Definition: bpf_filter.c:391
#define DLT_RAW
Definition: dlt.h:88
#define DLT_EN10MB
Definition: dlt.h:63
#define DLT_NULL
Definition: dlt.h:62
#define DLT_DOCSIS
Definition: dlt.h:465
#define DLT_IP_OVER_FC
Definition: dlt.h:365
#define DLT_FDDI
Definition: dlt.h:72
int pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, int(*check_usable)(const char *), get_if_flags_func get_flags_func)
Definition: fad-getad.c:146
void pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum, const char *fmt,...)
Definition: fmtutils.c:269
int install_bpf_program(pcap_t *p, struct bpf_program *fp)
Definition: optimize.c:2939
int snprintf(char *, size_t, const char *,...)
int ioctl(int, int, caddr_t)
int setsockopt(int, int, int, char *, int)
int read(int, char *, u_int)
int write(int, char *, u_int)
int socket(int, int, int)
int bind(int, struct sockaddr *, int)
#define _U_
Definition: pcap-dos.h:93
int errno
#define MAXIMUM_SNAPLEN
Definition: pcap-int.h:131
void pcap_cleanup_live_common(pcap_t *)
Definition: pcap.c:3987
int pcap_getnonblock_fd(pcap_t *)
Definition: pcap.c:3537
int pcap_setnonblock_fd(pcap_t *p, int)
Definition: pcap.c:3583
#define PCAP_VERSION_STRING
Definition: pcap-int.h:59
#define PCAP_CREATE_COMMON(ebuf, type)
Definition: pcap-int.h:474
static int get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
Definition: pcap-snoop.c:443
const char * pcap_lib_version(void)
Definition: pcap-snoop.c:464
static int pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
Definition: pcap-snoop.c:65
int pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
Definition: pcap-snoop.c:454
static int pcap_inject_snoop(pcap_t *p, const void *buf, int size)
Definition: pcap-snoop.c:143
pcap_t * pcap_create_interface(const char *device, char *ebuf)
Definition: pcap-snoop.c:420
static int can_be_bound(const char *name)
Definition: pcap-snoop.c:437
static int pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps)
Definition: pcap-snoop.c:161
static int pcap_activate_snoop(pcap_t *p)
Definition: pcap-snoop.c:203
#define PCAP_ERROR_RFMON_NOTSUP
Definition: pcap.h:344
void(* pcap_handler)(u_char *, const struct pcap_pkthdr *, const u_char *)
Definition: pcap.h:330
#define PCAP_ERRBUF_SIZE
Definition: pcap.h:152
#define PCAP_ERROR
Definition: pcap.h:339
struct bpf_insn * bf_insns
Definition: bpf.h:119
char * device
Definition: pcap-int.h:146
int rfmon
Definition: pcap-int.h:150
u_int buffer_size
Definition: pcap-int.h:148
bpf_u_int32 caplen
Definition: pcap.h:247
struct timeval ts
Definition: pcap.h:246
bpf_u_int32 len
Definition: pcap.h:248
struct pcap_stat stat
Definition: pcap-snoop.c:61
u_int ps_drop
Definition: pcap.h:256
u_int ps_recv
Definition: pcap.h:255
Definition: pcap-int.h:200
stats_op_t stats_op
Definition: pcap-int.h:320
activate_op_t activate_op
Definition: pcap-int.h:311
setnonblock_op_t setnonblock_op
Definition: pcap-int.h:319
setfilter_op_t setfilter_op
Definition: pcap-int.h:315
sig_atomic_t break_loop
Definition: pcap-int.h:225
int dlt_count
Definition: pcap-int.h:299
u_int bufsize
Definition: pcap-int.h:220
void * priv
Definition: pcap-int.h:227
getnonblock_op_t getnonblock_op
Definition: pcap-int.h:318
int offset
Definition: pcap-int.h:250
u_int * dlt_list
Definition: pcap-int.h:300
read_op_t read_op
Definition: pcap-int.h:204
void * buffer
Definition: pcap-int.h:221
int snapshot
Definition: pcap-int.h:247
setdirection_op_t setdirection_op
Definition: pcap-int.h:316
inject_op_t inject_op
Definition: pcap-int.h:313
struct bpf_program fcode
Definition: pcap-int.h:293
set_datalink_op_t set_datalink_op
Definition: pcap-int.h:317
char errbuf[256+1]
Definition: pcap-int.h:295
int linktype
Definition: pcap-int.h:248
int selectable_fd
Definition: pcap-int.h:274
int fd
Definition: pcap-int.h:214
struct pcap_opt opt
Definition: pcap-int.h:254