2 * The actual capturing loop, getting packets and storing it
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
28 * Capture loop (internal interface).
30 * It will open the input and output files, capture the packets,
31 * change ringbuffer output files while capturing and close all files again.
33 * The input file can be a network interface or capture pipe (unix only).
34 * The output file can be a single or a ringbuffer file handled by wiretap.
54 #ifdef HAVE_SYS_TYPES_H
55 # include <sys/types.h>
58 #ifdef HAVE_SYS_STAT_H
59 # include <sys/stat.h>
69 #include <epan/packet.h>
71 #include "capture_sync.h"
72 #include "pcap-util.h"
74 #include "simple_dialog.h"
75 #include "conditions.h"
76 #include "capture_stop_conditions.h"
77 #include "ringbuffer.h"
79 #include "wiretap/libpcap.h"
80 #include "wiretap/wtap.h"
81 #include "wiretap/wtap-capture.h"
83 #include <epan/prefs.h>
84 /* XXX - try to remove this later */
86 /* XXX - try to remove this later */
89 #include <epan/dissectors/packet-ap1394.h>
90 #include <epan/dissectors/packet-atalk.h>
91 #include <epan/dissectors/packet-atm.h>
92 #include <epan/dissectors/packet-clip.h>
93 #include <epan/dissectors/packet-eth.h>
94 #include <epan/dissectors/packet-fddi.h>
95 #include <epan/dissectors/packet-null.h>
96 #include <epan/dissectors/packet-ppp.h>
97 #include <epan/dissectors/packet-raw.h>
98 #include <epan/dissectors/packet-sll.h>
99 #include <epan/dissectors/packet-tr.h>
100 #include <epan/dissectors/packet-ieee80211.h>
101 #include <epan/dissectors/packet-chdlc.h>
102 #include <epan/dissectors/packet-prism.h>
103 #include <epan/dissectors/packet-ipfc.h>
104 #include <epan/dissectors/packet-arcnet.h>
110 * We don't want to do a "select()" on the pcap_t's file descriptor on
111 * BSD (because "select()" doesn't work correctly on BPF devices on at
112 * least some releases of some flavors of BSD), and we don't want to do
113 * it on Windows (because "select()" is something for sockets, not for
114 * arbitrary handles). (Note that "Windows" here includes Cygwin;
115 * even in its pretend-it's-UNIX environment, we're using WinPcap, not
118 * We *do* want to do it on other platforms, as, on other platforms (with
119 * the possible exception of Ultrix and Digital UNIX), the read timeout
120 * doesn't expire if no packets have arrived, so a "pcap_dispatch()" call
121 * will block until packets arrive, causing the UI to hang.
123 * XXX - the various BSDs appear to define BSD in <sys/param.h>; we don't
124 * want to include it if it's not present on this platform, however.
126 #if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__) && \
127 !defined(__bsdi__) && !defined(__APPLE__) && !defined(_WIN32) && \
129 # define MUST_DO_SELECT
133 typedef struct _loop_data {
135 gboolean go; /* TRUE as long as we're supposed to keep capturing */
136 int err; /* if non-zero, error seen while capturing */
137 gint packets_max; /* Number of packets we're supposed to capture - 0 means infinite */
138 gint packets_sync_pipe; /* packets not already send out to the sync_pipe */
139 packet_counts counts; /* several packet type counters */
141 /* pcap "input file" */
142 pcap_t *pcap_h; /* pcap handle */
143 gboolean pcap_err; /* TRUE if error from pcap */
144 #ifdef MUST_DO_SELECT
145 int pcap_fd; /* pcap file descriptor */
148 /* capture pipe (unix only "input file") */
149 gboolean from_cap_pipe; /* TRUE if we are capturing data from a capture pipe */
151 struct pcap_hdr cap_pipe_hdr;
152 int cap_pipe_fd; /* the file descriptor of the capture pipe */
153 gboolean cap_pipe_modified; /* TRUE if data in the pipe uses modified pcap headers */
154 gboolean cap_pipe_byte_swapped; /* TRUE if data in the pipe is byte swapped */
155 unsigned int cap_pipe_bytes_to_read;/* Used by cap_pipe_dispatch */
156 unsigned int cap_pipe_bytes_read; /* Used by cap_pipe_dispatch */
158 STATE_EXPECT_REC_HDR,
164 enum { PIPOK, PIPEOF, PIPERR, PIPNEXIST } cap_pipe_err;
167 /* wiretap (output file) */
168 wtap_dumper *wtap_pdh;
175 * Timeout, in milliseconds, for reads from the stream of captured packets.
177 #define CAP_READ_TIMEOUT 250
179 static void capture_loop_packet_cb(guchar *user, const struct pcap_pkthdr *phdr,
181 static void capture_loop_popup_errmsg(capture_options *capture_opts, const char *errmsg);
182 static void capture_loop_get_errmsg(char *errmsg, int errmsglen, const char *fname,
183 int err, gboolean is_close);
188 /* Take care of byte order in the libpcap headers read from pipes.
189 * (function taken from wiretap/libpcap.c) */
191 cap_pipe_adjust_header(loop_data *ld, struct pcap_hdr *hdr, struct pcaprec_hdr *rechdr)
193 if (ld->cap_pipe_byte_swapped) {
194 /* Byte-swap the record header fields. */
195 rechdr->ts_sec = BSWAP32(rechdr->ts_sec);
196 rechdr->ts_usec = BSWAP32(rechdr->ts_usec);
197 rechdr->incl_len = BSWAP32(rechdr->incl_len);
198 rechdr->orig_len = BSWAP32(rechdr->orig_len);
201 /* In file format version 2.3, the "incl_len" and "orig_len" fields were
202 swapped, in order to match the BPF header layout.
204 Unfortunately, some files were, according to a comment in the "libpcap"
205 source, written with version 2.3 in their headers but without the
206 interchanged fields, so if "incl_len" is greater than "orig_len" - which
207 would make no sense - we assume that we need to swap them. */
208 if (hdr->version_major == 2 &&
209 (hdr->version_minor < 3 ||
210 (hdr->version_minor == 3 && rechdr->incl_len > rechdr->orig_len))) {
213 temp = rechdr->orig_len;
214 rechdr->orig_len = rechdr->incl_len;
215 rechdr->incl_len = temp;
219 /* Mimic pcap_open_live() for pipe captures
220 * We check if "pipename" is "-" (stdin) or a FIFO, open it, and read the
222 * N.B. : we can't read the libpcap formats used in RedHat 6.1 or SuSE 6.3
223 * because we can't seek on pipes (see wiretap/libpcap.c for details) */
225 cap_pipe_open_live(char *pipename, struct pcap_hdr *hdr, loop_data *ld,
226 char *errmsg, int errmsgl)
228 struct stat pipe_stat;
232 unsigned int bytes_read;
234 struct timeval timeout;
237 * XXX Ethereal blocks until we return
239 if (strcmp(pipename, "-") == 0)
240 fd = 0; /* read from stdin */
242 if (stat(pipename, &pipe_stat) < 0) {
243 if (errno == ENOENT || errno == ENOTDIR)
244 ld->cap_pipe_err = PIPNEXIST;
246 g_snprintf(errmsg, errmsgl,
247 "The capture session could not be initiated "
248 "due to error on pipe: %s", strerror(errno));
249 ld->cap_pipe_err = PIPERR;
253 if (! S_ISFIFO(pipe_stat.st_mode)) {
254 if (S_ISCHR(pipe_stat.st_mode)) {
256 * Assume the user specified an interface on a system where
257 * interfaces are in /dev. Pretend we haven't seen it.
259 ld->cap_pipe_err = PIPNEXIST;
261 g_snprintf(errmsg, errmsgl,
262 "The capture session could not be initiated because\n"
263 "\"%s\" is neither an interface nor a pipe", pipename);
264 ld->cap_pipe_err = PIPERR;
268 fd = open(pipename, O_RDONLY | O_NONBLOCK);
270 g_snprintf(errmsg, errmsgl,
271 "The capture session could not be initiated "
272 "due to error on pipe open: %s", strerror(errno));
273 ld->cap_pipe_err = PIPERR;
278 ld->from_cap_pipe = TRUE;
280 /* read the pcap header */
283 while (bytes_read < sizeof magic) {
286 timeout.tv_usec = CAP_READ_TIMEOUT*1000;
287 sel_ret = select(fd+1, &rfds, NULL, NULL, &timeout);
289 g_snprintf(errmsg, errmsgl,
290 "Unexpected error from select: %s", strerror(errno));
292 } else if (sel_ret > 0) {
293 b = read(fd, ((char *)&magic)+bytes_read, sizeof magic-bytes_read);
296 g_snprintf(errmsg, errmsgl, "End of file on pipe during open");
298 g_snprintf(errmsg, errmsgl, "Error on pipe during open: %s",
308 /* Host that wrote it has our byte order, and was running
309 a program using either standard or ss990417 libpcap. */
310 ld->cap_pipe_byte_swapped = FALSE;
311 ld->cap_pipe_modified = FALSE;
313 case PCAP_MODIFIED_MAGIC:
314 /* Host that wrote it has our byte order, but was running
315 a program using either ss990915 or ss991029 libpcap. */
316 ld->cap_pipe_byte_swapped = FALSE;
317 ld->cap_pipe_modified = TRUE;
319 case PCAP_SWAPPED_MAGIC:
320 /* Host that wrote it has a byte order opposite to ours,
321 and was running a program using either standard or
323 ld->cap_pipe_byte_swapped = TRUE;
324 ld->cap_pipe_modified = FALSE;
326 case PCAP_SWAPPED_MODIFIED_MAGIC:
327 /* Host that wrote it out has a byte order opposite to
328 ours, and was running a program using either ss990915
329 or ss991029 libpcap. */
330 ld->cap_pipe_byte_swapped = TRUE;
331 ld->cap_pipe_modified = TRUE;
334 /* Not a "libpcap" type we know about. */
335 g_snprintf(errmsg, errmsgl, "Unrecognized libpcap format");
339 /* Read the rest of the header */
341 while (bytes_read < sizeof(struct pcap_hdr)) {
344 timeout.tv_usec = CAP_READ_TIMEOUT*1000;
345 sel_ret = select(fd+1, &rfds, NULL, NULL, &timeout);
347 g_snprintf(errmsg, errmsgl,
348 "Unexpected error from select: %s", strerror(errno));
350 } else if (sel_ret > 0) {
351 b = read(fd, ((char *)hdr)+bytes_read,
352 sizeof(struct pcap_hdr) - bytes_read);
355 g_snprintf(errmsg, errmsgl, "End of file on pipe during open");
357 g_snprintf(errmsg, errmsgl, "Error on pipe during open: %s",
365 if (ld->cap_pipe_byte_swapped) {
366 /* Byte-swap the header fields about which we care. */
367 hdr->version_major = BSWAP16(hdr->version_major);
368 hdr->version_minor = BSWAP16(hdr->version_minor);
369 hdr->snaplen = BSWAP32(hdr->snaplen);
370 hdr->network = BSWAP32(hdr->network);
373 if (hdr->version_major < 2) {
374 g_snprintf(errmsg, errmsgl, "Unable to read old libpcap format");
378 ld->cap_pipe_state = STATE_EXPECT_REC_HDR;
379 ld->cap_pipe_err = PIPOK;
383 ld->cap_pipe_err = PIPERR;
390 /* We read one record from the pipe, take care of byte order in the record
391 * header, write the record to the capture file, and update capture statistics. */
393 cap_pipe_dispatch(int fd, loop_data *ld, struct pcap_hdr *hdr,
394 struct pcaprec_modified_hdr *rechdr, guchar *data,
395 char *errmsg, int errmsgl)
397 struct pcap_pkthdr phdr;
399 enum { PD_REC_HDR_READ, PD_DATA_READ, PD_PIPE_EOF, PD_PIPE_ERR,
402 switch (ld->cap_pipe_state) {
404 case STATE_EXPECT_REC_HDR:
405 ld->cap_pipe_bytes_to_read = ld->cap_pipe_modified ?
406 sizeof(struct pcaprec_modified_hdr) : sizeof(struct pcaprec_hdr);
407 ld->cap_pipe_bytes_read = 0;
408 ld->cap_pipe_state = STATE_READ_REC_HDR;
411 case STATE_READ_REC_HDR:
412 b = read(fd, ((char *)rechdr)+ld->cap_pipe_bytes_read,
413 ld->cap_pipe_bytes_to_read - ld->cap_pipe_bytes_read);
416 result = PD_PIPE_EOF;
418 result = PD_PIPE_ERR;
421 if ((ld->cap_pipe_bytes_read += b) < ld->cap_pipe_bytes_to_read)
423 result = PD_REC_HDR_READ;
426 case STATE_EXPECT_DATA:
427 ld->cap_pipe_bytes_read = 0;
428 ld->cap_pipe_state = STATE_READ_DATA;
431 case STATE_READ_DATA:
432 b = read(fd, data+ld->cap_pipe_bytes_read, rechdr->hdr.incl_len - ld->cap_pipe_bytes_read);
435 result = PD_PIPE_EOF;
437 result = PD_PIPE_ERR;
440 if ((ld->cap_pipe_bytes_read += b) < rechdr->hdr.incl_len)
442 result = PD_DATA_READ;
446 g_snprintf(errmsg, errmsgl, "cap_pipe_dispatch: invalid state");
449 } /* switch (ld->cap_pipe_state) */
452 * We've now read as much data as we were expecting, so process it.
456 case PD_REC_HDR_READ:
457 /* We've read the header. Take care of byte order. */
458 cap_pipe_adjust_header(ld, hdr, &rechdr->hdr);
459 if (rechdr->hdr.incl_len > WTAP_MAX_PACKET_SIZE) {
460 g_snprintf(errmsg, errmsgl, "Frame %u too long (%d bytes)",
461 ld->counts.total+1, rechdr->hdr.incl_len);
464 ld->cap_pipe_state = STATE_EXPECT_DATA;
468 /* Fill in a "struct pcap_pkthdr", and process the packet. */
469 phdr.ts.tv_sec = rechdr->hdr.ts_sec;
470 phdr.ts.tv_usec = rechdr->hdr.ts_usec;
471 phdr.caplen = rechdr->hdr.incl_len;
472 phdr.len = rechdr->hdr.orig_len;
474 capture_loop_packet_cb((guchar *)ld, &phdr, data);
476 ld->cap_pipe_state = STATE_EXPECT_REC_HDR;
480 ld->cap_pipe_err = PIPEOF;
484 g_snprintf(errmsg, errmsgl, "Error reading from pipe: %s",
491 ld->cap_pipe_err = PIPERR;
492 /* Return here rather than inside the switch to prevent GCC warning */
495 #endif /* not _WIN32 */
498 /* open the capture input file (pcap or capture pipe) */
499 static int capture_loop_open_input(capture_options *capture_opts, loop_data *ld, char *errmsg, int errmsg_len) {
500 gchar open_err_str[PCAP_ERRBUF_SIZE];
501 const char *set_linktype_err_str;
504 WORD wVersionRequested;
507 static const char ppamsg[] = "can't find PPA for ";
511 /* Initialize Windows Socket if we are in a WIN32 OS
512 This needs to be done before querying the interface for network/netmask */
514 /* XXX - do we really require 1.1 or earlier?
515 Are there any versions that support only 2.0 or higher? */
516 wVersionRequested = MAKEWORD(1, 1);
517 err = WSAStartup(wVersionRequested, &wsaData);
522 g_snprintf(errmsg, errmsg_len,
523 "Couldn't initialize Windows Sockets: Network system not ready for network communication");
526 case WSAVERNOTSUPPORTED:
527 g_snprintf(errmsg, errmsg_len,
528 "Couldn't initialize Windows Sockets: Windows Sockets version %u.%u not supported",
529 LOBYTE(wVersionRequested), HIBYTE(wVersionRequested));
533 g_snprintf(errmsg, errmsg_len,
534 "Couldn't initialize Windows Sockets: Blocking operation is in progress");
538 g_snprintf(errmsg, errmsg_len,
539 "Couldn't initialize Windows Sockets: Limit on the number of tasks supported by this WinSock implementation has been reached");
543 g_snprintf(errmsg, errmsg_len,
544 "Couldn't initialize Windows Sockets: Bad pointer passed to WSAStartup");
548 g_snprintf(errmsg, errmsg_len,
549 "Couldn't initialize Windows Sockets: error %d", err);
556 /* Open the network interface to capture from it.
557 Some versions of libpcap may put warnings into the error buffer
558 if they succeed; to tell if that's happened, we have to clear
559 the error buffer, and check if it's still a null string. */
560 open_err_str[0] = '\0';
561 ld->pcap_h = pcap_open_live(capture_opts->iface,
562 capture_opts->has_snaplen ? capture_opts->snaplen :
563 WTAP_MAX_PACKET_SIZE,
564 capture_opts->promisc_mode, CAP_READ_TIMEOUT,
567 if (ld->pcap_h != NULL) {
568 /* we've opened "iface" as a network device */
570 /* try to set the capture buffer size */
571 if (pcap_setbuff(ld->pcap_h, capture_opts->buffer_size * 1024 * 1024) != 0) {
572 simple_dialog(ESD_TYPE_INFO, ESD_BTN_OK,
573 "%sCouldn't set the capture buffer size!%s\n"
575 "The capture buffer size of %luMB seems to be too high for your machine,\n"
576 "the default of 1MB will be used.\n"
578 "Nonetheless, the capture is started.\n",
579 simple_dialog_primary_start(), simple_dialog_primary_end(), capture_opts->buffer_size);
583 /* setting the data link type only works on real interfaces */
584 if (capture_opts->linktype != -1) {
585 set_linktype_err_str = set_pcap_linktype(ld->pcap_h, capture_opts->iface,
586 capture_opts->linktype);
587 if (set_linktype_err_str != NULL) {
588 g_snprintf(errmsg, errmsg_len, "Unable to set data link type (%s).",
589 set_linktype_err_str);
594 /* We couldn't open "iface" as a network device. */
596 /* On Windows, we don't support capturing on pipes, so we give up.
597 If this is a child process that does the capturing in sync
598 mode or fork mode, it shouldn't do any UI stuff until we pop up the
599 capture-progress window, and, since we couldn't start the
600 capture, we haven't popped it up. */
601 if (!capture_opts->capture_child) {
602 main_window_update();
605 /* On Win32 OSes, the capture devices are probably available to all
606 users; don't warn about permissions problems.
608 Do, however, warn that WAN devices aren't supported. */
609 g_snprintf(errmsg, errmsg_len,
610 "The capture session could not be initiated (%s).\n"
611 "Please check that you have the proper interface specified.\n"
613 "Note that the WinPcap 2.x version of the driver Ethereal uses for packet\n"
614 "capture on Windows doesn't support capturing on PPP/WAN interfaces in\n"
615 "Windows NT/2000/XP/2003 Server, and that the WinPcap 3.0 and later versions\n"
616 "don't support capturing on PPP/WAN interfaces at all.",
620 /* try to open iface as a pipe */
621 ld->cap_pipe_fd = cap_pipe_open_live(capture_opts->iface, &ld->cap_pipe_hdr, ld, errmsg, errmsg_len);
623 if (ld->cap_pipe_fd == -1) {
625 /* If this is a child process that does the capturing in sync
626 * mode or fork mode, it shouldn't do any UI stuff until we pop up the
627 * capture-progress window, and, since we couldn't start the
628 * capture, we haven't popped it up.
630 if (!capture_opts->capture_child) {
631 main_window_update();
634 if (ld->cap_pipe_err == PIPNEXIST) {
635 /* Pipe doesn't exist, so output message for interface */
637 /* If we got a "can't find PPA for XXX" message, warn the user (who
638 is running Ethereal on HP-UX) that they don't have a version
639 of libpcap that properly handles HP-UX (libpcap 0.6.x and later
640 versions, which properly handle HP-UX, say "can't find /dev/dlpi
641 PPA for XXX" rather than "can't find PPA for XXX"). */
642 if (strncmp(open_err_str, ppamsg, sizeof ppamsg - 1) == 0)
645 "You are running Ethereal with a version of the libpcap library\n"
646 "that doesn't handle HP-UX network devices well; this means that\n"
647 "Ethereal may not be able to capture packets.\n"
649 "To fix this, you should install libpcap 0.6.2, or a later version\n"
650 "of libpcap, rather than libpcap 0.4 or 0.5.x. It is available in\n"
651 "packaged binary form from the Software Porting And Archive Centre\n"
652 "for HP-UX; the Centre is at http://hpux.connect.org.uk/ - the page\n"
653 "at the URL lists a number of mirror sites.";
656 g_snprintf(errmsg, errmsg_len,
657 "The capture session could not be initiated (%s).\n"
658 "Please check to make sure you have sufficient permissions, and that\n"
659 "you have the proper interface or pipe specified.%s", open_err_str,
663 * Else pipe (or file) does exist and cap_pipe_open_live() has
668 /* cap_pipe_open_live() succeeded; don't want
669 error message from pcap_open_live() */
670 open_err_str[0] = '\0';
674 #ifdef MUST_DO_SELECT
675 if (!ld->from_cap_pipe) ld->pcap_fd = pcap_fileno(ld->pcap_h);
678 /* Does "open_err_str" contain a non-empty string? If so, "pcap_open_live()"
679 returned a warning; print it, but keep capturing. */
680 if (open_err_str[0] != '\0')
681 g_warning("%s.", open_err_str);
687 /* open the capture input file (pcap or capture pipe) */
688 static void capture_loop_close_input(loop_data *ld) {
690 /* if open, close the capture pipe "input file" */
691 if (ld->cap_pipe_fd >= 0) {
692 g_assert(ld->from_cap_pipe);
693 close(ld->cap_pipe_fd);
697 /* if open, close the pcap "input file" */
698 if(ld->pcap_h != NULL) {
699 g_assert(!ld->from_cap_pipe);
700 pcap_close(ld->pcap_h);
704 /* Shut down windows sockets */
710 /* init the capture filter */
711 static int capture_loop_init_filter(loop_data *ld, const gchar * iface, gchar * cfilter, char *errmsg, int errmsg_len) {
712 bpf_u_int32 netnum, netmask;
713 gchar lookup_net_err_str[PCAP_ERRBUF_SIZE];
714 struct bpf_program fcode;
716 /* capture filters only work on real interfaces */
717 if (cfilter && !ld->from_cap_pipe) {
718 /* A capture filter was specified; set it up. */
719 if (pcap_lookupnet(iface, &netnum, &netmask, lookup_net_err_str) < 0) {
721 * Well, we can't get the netmask for this interface; it's used
722 * only for filters that check for broadcast IP addresses, so
723 * we just punt and use 0. It might be nice to warn the user,
724 * but that's a pain in a GUI application, as it'd involve popping
725 * up a message box, and it's not clear how often this would make
726 * a difference (only filters that check for IP broadcast addresses
731 if (pcap_compile(ld->pcap_h, &fcode, cfilter, 1, netmask) < 0) {
732 dfilter_t *rfcode = NULL;
733 /* filter string invalid, did the user tried a display filter? */
734 if (dfilter_compile(cfilter, &rfcode) && rfcode != NULL) {
735 g_snprintf(errmsg, errmsg_len,
736 "%sInvalid capture filter: \"%s\"!%s\n"
738 "That string looks like a valid display filter; however, it isn't a valid\n"
739 "capture filter (%s).\n"
741 "Note that display filters and capture filters don't have the same syntax,\n"
742 "so you can't use most display filter expressions as capture filters.\n"
744 "See the help for a description of the capture filter syntax.",
745 simple_dialog_primary_start(), cfilter, simple_dialog_primary_end(),
746 pcap_geterr(ld->pcap_h));
747 dfilter_free(rfcode);
749 g_snprintf(errmsg, errmsg_len,
750 "%sInvalid capture filter: \"%s\"!%s\n"
752 "That string isn't a valid capture filter (%s).\n"
753 "See the help for a description of the capture filter syntax.",
754 simple_dialog_primary_start(), cfilter, simple_dialog_primary_end(),
755 pcap_geterr(ld->pcap_h));
759 if (pcap_setfilter(ld->pcap_h, &fcode) < 0) {
760 g_snprintf(errmsg, errmsg_len, "Can't install filter (%s).",
761 pcap_geterr(ld->pcap_h));
770 /* open the wiretap part of the capture output file */
771 static int capture_loop_open_wiretap_output(capture_options *capture_opts, loop_data *ld, char *errmsg, int errmsg_len) {
777 /* get packet encapsulation type and snaplen */
779 if (ld->from_cap_pipe) {
780 pcap_encap = ld->cap_pipe_hdr.network;
781 file_snaplen = ld->cap_pipe_hdr.snaplen;
785 pcap_encap = get_pcap_linktype(ld->pcap_h, capture_opts->iface);
786 file_snaplen = pcap_snapshot(ld->pcap_h);
789 /* Set up to write to the capture file. */
790 ld->wtap_linktype = wtap_pcap_encap_to_wtap_encap(pcap_encap);
791 if (ld->wtap_linktype == WTAP_ENCAP_UNKNOWN) {
792 g_snprintf(errmsg, errmsg_len,
793 "The network you're capturing from is of a type"
794 " that Ethereal doesn't support (data link type %d).", pcap_encap);
797 if (capture_opts->multi_files_on) {
798 ld->wtap_pdh = ringbuf_init_wtap_dump_fdopen(WTAP_FILE_PCAP, ld->wtap_linktype,
801 ld->wtap_pdh = wtap_dump_fdopen(capture_opts->save_file_fd, WTAP_FILE_PCAP,
802 ld->wtap_linktype, file_snaplen, &err);
805 if (ld->wtap_pdh == NULL) {
806 /* We couldn't set up to write to the capture file. */
809 case WTAP_ERR_CANT_OPEN:
810 strcpy(errmsg, "The file to which the capture would be saved"
811 " couldn't be created for some unknown reason.");
814 case WTAP_ERR_SHORT_WRITE:
815 strcpy(errmsg, "A full header couldn't be written to the file"
816 " to which the capture would be saved.");
821 g_snprintf(errmsg, errmsg_len,
822 "The file to which the capture would be"
823 " saved (\"%s\") could not be opened: Error %d.",
824 capture_opts->save_file, err);
826 g_snprintf(errmsg, errmsg_len,
827 "The file to which the capture would be"
828 " saved (\"%s\") could not be opened: %s.",
829 capture_opts->save_file, strerror(err));
840 static gboolean capture_loop_close_output(capture_options *capture_opts, loop_data *ld, int *err_close) {
841 if (capture_opts->multi_files_on) {
842 return ringbuf_wtap_dump_close(&capture_opts->save_file, err_close);
844 return wtap_dump_close(ld->wtap_pdh, err_close);
848 /* dispatch incoming packets (pcap or capture pipe) */
850 capture_loop_dispatch(capture_options *capture_opts, loop_data *ld,
851 char *errmsg, int errmsg_len) {
855 struct timeval timeout;
857 struct pcaprec_modified_hdr rechdr;
858 guchar pcap_data[WTAP_MAX_PACKET_SIZE];
862 /* dispatch from capture pipe */
863 if (ld->from_cap_pipe) {
865 FD_SET(ld->cap_pipe_fd, &set1);
867 timeout.tv_usec = CAP_READ_TIMEOUT*1000;
868 sel_ret = select(ld->cap_pipe_fd+1, &set1, NULL, NULL, &timeout);
871 if (sel_ret < 0 && errno != EINTR) {
872 g_snprintf(errmsg, errmsg_len,
873 "Unexpected error from select: %s", strerror(errno));
874 capture_loop_popup_errmsg(capture_opts, errmsg);
879 * "select()" says we can read from the pipe without blocking
881 inpkts = cap_pipe_dispatch(ld->cap_pipe_fd, ld, &ld->cap_pipe_hdr, &rechdr, pcap_data,
891 /* dispatch from pcap using select */
892 #ifdef MUST_DO_SELECT
894 * Sigh. The semantics of the read timeout argument to
895 * "pcap_open_live()" aren't particularly well specified by
896 * the "pcap" man page - at least with the BSD BPF code, the
897 * intent appears to be, at least in part, a way of cutting
898 * down the number of reads done on a capture, by blocking
899 * until the buffer fills or a timer expires - and the Linux
900 * libpcap doesn't actually support it, so we can't use it
901 * to break out of the "pcap_dispatch()" every 1/4 of a second
902 * or so. Linux's libpcap is not the only libpcap that doesn't
903 * support the read timeout.
905 * Furthermore, at least on Solaris, the bufmod STREAMS module's
906 * read timeout won't go off if no data has arrived, i.e. it cannot
907 * be used to guarantee that a read from a DLPI stream will return
908 * within a specified amount of time regardless of whether any
909 * data arrives or not.
911 * Thus, on all platforms other than BSD, we do a "select()" on the
912 * file descriptor for the capture, with a timeout of CAP_READ_TIMEOUT
913 * milliseconds, or CAP_READ_TIMEOUT*1000 microseconds.
915 * "select()", on BPF devices, doesn't work as you might expect;
916 * at least on some versions of some flavors of BSD, the timer
917 * doesn't start until a read is done, so it won't expire if
918 * only a "select()" or "poll()" is posted.
921 FD_SET(ld->pcap_fd, &set1);
923 timeout.tv_usec = CAP_READ_TIMEOUT*1000;
924 sel_ret = select(ld->pcap_fd+1, &set1, NULL, NULL, &timeout);
927 * "select()" says we can read from it without blocking; go for
930 inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *)ld);
937 if (sel_ret < 0 && errno != EINTR) {
938 g_snprintf(errmsg, errmsg_len,
939 "Unexpected error from select: %s", strerror(errno));
940 capture_loop_popup_errmsg(capture_opts, errmsg);
945 /* dispatch from pcap without select */
946 inpkts = pcap_dispatch(ld->pcap_h, 1, capture_loop_packet_cb, (gchar *) ld);
951 #endif /* MUST_DO_SELECT */
959 * This needs to be static, so that the SIGUSR1 handler can clear the "go"
964 /* Do the low-level work of a capture.
965 Returns TRUE if it succeeds, FALSE otherwise. */
967 capture_loop_start(capture_options *capture_opts, gboolean *stats_known, struct pcap_stat *stats)
969 time_t upd_time, cur_time;
971 int err_close, inpkts;
972 condition *cnd_file_duration = NULL;
973 condition *cnd_autostop_files = NULL;
974 condition *cnd_autostop_size = NULL;
975 condition *cnd_autostop_duration = NULL;
976 guint32 autostop_files = 0;
979 capture_info capture_ui;
982 gboolean show_info = capture_opts->show_info || !capture_opts->sync_mode;
985 /* init the loop data */
987 if (capture_opts->has_autostop_packets)
988 ld.packets_max = capture_opts->autostop_packets;
990 ld.packets_max = 0; /* no limit */
991 ld.err = 0; /* no error seen yet */
992 ld.wtap_linktype = WTAP_ENCAP_UNKNOWN;
994 ld.from_cap_pipe = FALSE;
995 ld.packets_sync_pipe = 0;
1004 ld.counts.netbios = 0;
1005 ld.counts.vines = 0;
1006 ld.counts.other = 0;
1010 ld.cap_pipe_fd = -1;
1012 #ifdef MUST_DO_SELECT
1016 /* We haven't yet gotten the capture statistics. */
1017 *stats_known = FALSE;
1020 /* open the "input file" from network interface or capture pipe */
1021 if (!capture_loop_open_input(capture_opts, &ld, errmsg, sizeof(errmsg))) {
1025 /* init the input filter from the network interface (capture pipe will do nothing) */
1026 if (!capture_loop_init_filter(&ld, capture_opts->iface, capture_opts->cfilter, errmsg, sizeof(errmsg))) {
1030 /* open the wiretap part of the output file (the output file is already open) */
1031 if (!capture_loop_open_wiretap_output(capture_opts, &ld, errmsg, sizeof(errmsg))) {
1035 /* XXX - capture SIGTERM and close the capture, in case we're on a
1036 Linux 2.0[.x] system and you have to explicitly close the capture
1037 stream in order to turn promiscuous mode off? We need to do that
1038 in other places as well - and I don't think that works all the
1039 time in any case, due to libpcap bugs. */
1041 if (capture_opts->capture_child) {
1042 /* Well, we should be able to start capturing.
1044 This is the child process for a sync mode capture, so sync out
1045 the capture file, so the header makes it to the file system,
1046 and send a "capture started successfully and capture file created"
1047 message to our parent so that they'll open the capture file and
1048 update its windows to indicate that we have a live capture in
1050 fflush(wtap_dump_file(ld.wtap_pdh));
1051 sync_pipe_capstart_to_parent();
1054 /* initialize capture stop (and alike) conditions */
1055 init_capture_stop_conditions();
1056 /* create stop conditions */
1057 if (capture_opts->has_autostop_filesize)
1059 cnd_new(CND_CLASS_CAPTURESIZE,(long)capture_opts->autostop_filesize);
1060 if (capture_opts->has_autostop_duration)
1061 cnd_autostop_duration =
1062 cnd_new(CND_CLASS_TIMEOUT,(gint32)capture_opts->autostop_duration);
1064 if (capture_opts->multi_files_on) {
1065 if (capture_opts->has_file_duration)
1067 cnd_new(CND_CLASS_TIMEOUT, capture_opts->file_duration);
1069 if (capture_opts->has_autostop_files)
1070 cnd_autostop_files =
1071 cnd_new(CND_CLASS_CAPTURESIZE, capture_opts->autostop_files);
1074 /* start capture info dialog */
1076 capture_ui.callback_data = &ld;
1077 capture_ui.counts = &ld.counts;
1078 capture_info_create(&capture_ui, capture_opts->iface);
1081 /* init the time values */
1082 start_time = time(NULL);
1083 upd_time = time(NULL);
1085 /* WOW, everything is prepared! */
1086 /* please fasten your seat belts, we will enter now the actual capture loop */
1088 main_window_update();
1090 /* dispatch incoming packets */
1091 inpkts = capture_loop_dispatch(capture_opts, &ld, errmsg, sizeof(errmsg));
1094 ld.packets_sync_pipe += inpkts;
1096 /* check capture size condition */
1097 if (cnd_autostop_size != NULL && cnd_eval(cnd_autostop_size,
1098 (guint32)wtap_get_bytes_dumped(ld.wtap_pdh))){
1099 /* Capture size limit reached, do we have another file? */
1100 if (capture_opts->multi_files_on) {
1101 if (cnd_autostop_files != NULL && cnd_eval(cnd_autostop_files, ++autostop_files)) {
1102 /* no files left: stop here */
1107 /* Switch to the next ringbuffer file */
1108 if (ringbuf_switch_file(&ld.wtap_pdh, &capture_opts->save_file, &capture_opts->save_file_fd, &ld.err)) {
1109 /* File switch succeeded: reset the conditions */
1110 cnd_reset(cnd_autostop_size);
1111 if (cnd_file_duration) {
1112 cnd_reset(cnd_file_duration);
1115 /* File switch failed: stop here */
1120 /* single file, stop now */
1124 } /* cnd_autostop_size */
1127 /* Only update once a second so as not to overload slow displays */
1128 cur_time = time(NULL);
1129 if (cur_time > upd_time) {
1130 upd_time = cur_time;
1132 /*if (pcap_stats(pch, stats) >= 0) {
1133 *stats_known = TRUE;
1136 /* calculate and display running time */
1138 cur_time -= start_time;
1139 capture_ui.running_time = cur_time;
1140 capture_ui.new_packets = ld.packets_sync_pipe;
1141 capture_info_update(&capture_ui);
1144 /* Let the parent process know. */
1145 if (ld.packets_sync_pipe) {
1147 fflush(wtap_dump_file(ld.wtap_pdh));
1149 if (capture_opts->capture_child) {
1150 /* This is the child process for a sync mode capture, so send
1151 our parent a message saying we've written out "ld.sync_packets"
1152 packets to the capture file. */
1153 sync_pipe_packet_count_to_parent(ld.packets_sync_pipe);
1156 ld.packets_sync_pipe = 0;
1159 /* check capture duration condition */
1160 if (cnd_autostop_duration != NULL && cnd_eval(cnd_autostop_duration)) {
1161 /* The maximum capture time has elapsed; stop the capture. */
1166 /* check capture file duration condition */
1167 if (cnd_file_duration != NULL && cnd_eval(cnd_file_duration)) {
1168 /* duration limit reached, do we have another file? */
1169 if (capture_opts->multi_files_on) {
1170 if (cnd_autostop_files != NULL && cnd_eval(cnd_autostop_files, ++autostop_files)) {
1171 /* no files left: stop here */
1176 /* Switch to the next ringbuffer file */
1177 if (ringbuf_switch_file(&ld.wtap_pdh, &capture_opts->save_file, &capture_opts->save_file_fd, &ld.err)) {
1178 /* file switch succeeded: reset the conditions */
1179 cnd_reset(cnd_file_duration);
1180 if(cnd_autostop_size)
1181 cnd_reset(cnd_autostop_size);
1183 /* File switch failed: stop here */
1188 /* single file, stop now */
1192 } /* cnd_file_duration */
1195 } /* while (ld.go) */
1197 /* close capture info dialog */
1199 capture_info_destroy(&capture_ui);
1202 /* delete stop conditions */
1203 if (cnd_file_duration != NULL)
1204 cnd_delete(cnd_file_duration);
1205 if (cnd_autostop_files != NULL)
1206 cnd_delete(cnd_autostop_files);
1207 if (cnd_autostop_size != NULL)
1208 cnd_delete(cnd_autostop_size);
1209 if (cnd_autostop_duration != NULL)
1210 cnd_delete(cnd_autostop_duration);
1212 /* did we had a pcap (input) error? */
1214 g_snprintf(errmsg, sizeof(errmsg), "Error while capturing packets: %s",
1215 pcap_geterr(ld.pcap_h));
1216 capture_loop_popup_errmsg(capture_opts, errmsg);
1219 else if (ld.from_cap_pipe && ld.cap_pipe_err == PIPERR)
1220 capture_loop_popup_errmsg(capture_opts, errmsg);
1223 /* did we had an error while capturing? */
1227 capture_loop_get_errmsg(errmsg, sizeof(errmsg), capture_opts->save_file, ld.err,
1229 capture_loop_popup_errmsg(capture_opts, errmsg);
1233 /* close the wiretap (output) file */
1234 close_ok = capture_loop_close_output(capture_opts, &ld, &err_close);
1236 /* If we've displayed a message about a write error, there's no point
1237 in displaying another message about an error on close. */
1238 if (!close_ok && write_ok) {
1239 capture_loop_get_errmsg(errmsg, sizeof(errmsg), capture_opts->save_file, err_close,
1241 capture_loop_popup_errmsg(capture_opts, errmsg);
1245 * XXX We exhibit different behaviour between normal mode and sync mode
1246 * when the pipe is stdin and not already at EOF. If we're a child, the
1247 * parent's stdin isn't closed, so if the user starts another capture,
1248 * cap_pipe_open_live() will very likely not see the expected magic bytes and
1249 * will say "Unrecognized libpcap format". On the other hand, in normal
1250 * mode, cap_pipe_open_live() will say "End of file on pipe during open".
1253 /* get packet drop statistics from pcap */
1254 if(ld.pcap_h != NULL) {
1255 g_assert(!ld.from_cap_pipe);
1256 /* Get the capture statistics, so we know how many packets were
1258 if (pcap_stats(ld.pcap_h, stats) >= 0) {
1259 *stats_known = TRUE;
1260 if (capture_opts->capture_child) {
1261 /* Let the parent process know. */
1262 sync_pipe_drops_to_parent(stats->ps_drop);
1265 g_snprintf(errmsg, sizeof(errmsg),
1266 "Can't get packet-drop statistics: %s",
1267 pcap_geterr(ld.pcap_h));
1268 capture_loop_popup_errmsg(capture_opts, errmsg);
1272 /* close the input file (pcap or capture pipe) */
1273 capture_loop_close_input(&ld);
1275 /* ok, if the write and the close were successful. */
1276 return write_ok && close_ok;
1279 if (capture_opts->multi_files_on) {
1280 /* cleanup ringbuffer */
1281 ringbuf_error_cleanup();
1283 /* We can't use the save file, and we have no wtap_dump stream
1284 to close in order to close it, so close the FD directly. */
1285 close(capture_opts->save_file_fd);
1287 /* We couldn't even start the capture, so get rid of the capture
1289 unlink(capture_opts->save_file); /* silently ignore error */
1290 g_free(capture_opts->save_file);
1292 capture_opts->save_file = NULL;
1293 capture_loop_popup_errmsg(capture_opts, errmsg);
1295 /* close the input file (pcap or cap_pipe) */
1296 capture_loop_close_input(&ld);
1302 void capture_loop_stop(void)
1309 capture_loop_get_errmsg(char *errmsg, int errmsglen, const char *fname,
1310 int err, gboolean is_close)
1315 g_snprintf(errmsg, errmsglen,
1316 "Not all the packets could be written to the file"
1317 " to which the capture was being saved\n"
1318 "(\"%s\") because there is no space left on the file system\n"
1319 "on which that file resides.",
1325 g_snprintf(errmsg, errmsglen,
1326 "Not all the packets could be written to the file"
1327 " to which the capture was being saved\n"
1328 "(\"%s\") because you are too close to, or over,"
1329 " your disk quota\n"
1330 "on the file system on which that file resides.",
1335 case WTAP_ERR_CANT_CLOSE:
1336 g_snprintf(errmsg, errmsglen,
1337 "The file to which the capture was being saved"
1338 " couldn't be closed for some unknown reason.");
1341 case WTAP_ERR_SHORT_WRITE:
1342 g_snprintf(errmsg, errmsglen,
1343 "Not all the packets could be written to the file"
1344 " to which the capture was being saved\n"
1351 g_snprintf(errmsg, errmsglen,
1352 "The file to which the capture was being saved\n"
1353 "(\"%s\") could not be closed: %s.",
1354 fname, wtap_strerror(err));
1356 g_snprintf(errmsg, errmsglen,
1357 "An error occurred while writing to the file"
1358 " to which the capture was being saved\n"
1360 fname, wtap_strerror(err));
1367 capture_loop_popup_errmsg(capture_options *capture_opts, const char *errmsg)
1369 if (capture_opts->capture_child) {
1370 /* This is the child process for a sync mode capture.
1371 Send the error message to our parent, so they can display a
1372 dialog box containing it. */
1373 sync_pipe_errmsg_to_parent(errmsg);
1375 /* Display the dialog box ourselves; there's no parent. */
1376 simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", errmsg);
1381 /* one packet was captured, process it */
1383 capture_loop_packet_cb(guchar *user, const struct pcap_pkthdr *phdr,
1386 struct wtap_pkthdr whdr;
1387 union wtap_pseudo_header pseudo_header;
1388 loop_data *ld = (loop_data *) user;
1391 /* if the user told us to stop after x packets, do we have enough? */
1393 if ((ld->packets_max > 0) && (ld->counts.total >= ld->packets_max))
1398 /* Convert from libpcap to Wiretap format.
1399 If that fails, set "ld->go" to FALSE, to stop the capture, and set
1400 "ld->err" to the error. */
1401 pd = wtap_process_pcap_packet(ld->wtap_linktype, phdr, pd, &pseudo_header,
1410 /* We're supposed to write the packet to a file; do so.
1411 If this fails, set "ld->go" to FALSE, to stop the capture, and set
1412 "ld->err" to the error. */
1413 if (!wtap_dump(ld->wtap_pdh, &whdr, &pseudo_header, pd, &err)) {
1419 switch (ld->wtap_linktype) {
1420 case WTAP_ENCAP_ETHERNET:
1421 capture_eth(pd, 0, whdr.caplen, &ld->counts);
1423 case WTAP_ENCAP_FDDI:
1424 case WTAP_ENCAP_FDDI_BITSWAPPED:
1425 capture_fddi(pd, whdr.caplen, &ld->counts);
1427 case WTAP_ENCAP_PRISM_HEADER:
1428 capture_prism(pd, 0, whdr.caplen, &ld->counts);
1430 case WTAP_ENCAP_TOKEN_RING:
1431 capture_tr(pd, 0, whdr.caplen, &ld->counts);
1433 case WTAP_ENCAP_NULL:
1434 capture_null(pd, whdr.caplen, &ld->counts);
1436 case WTAP_ENCAP_PPP:
1437 capture_ppp_hdlc(pd, 0, whdr.caplen, &ld->counts);
1439 case WTAP_ENCAP_RAW_IP:
1440 capture_raw(pd, whdr.caplen, &ld->counts);
1442 case WTAP_ENCAP_SLL:
1443 capture_sll(pd, whdr.caplen, &ld->counts);
1445 case WTAP_ENCAP_LINUX_ATM_CLIP:
1446 capture_clip(pd, whdr.caplen, &ld->counts);
1448 case WTAP_ENCAP_IEEE_802_11:
1449 case WTAP_ENCAP_IEEE_802_11_WITH_RADIO:
1450 capture_ieee80211(pd, 0, whdr.caplen, &ld->counts);
1452 case WTAP_ENCAP_CHDLC:
1453 capture_chdlc(pd, 0, whdr.caplen, &ld->counts);
1455 case WTAP_ENCAP_LOCALTALK:
1456 capture_llap(&ld->counts);
1458 case WTAP_ENCAP_ATM_PDUS:
1459 capture_atm(&pseudo_header, pd, whdr.caplen, &ld->counts);
1461 case WTAP_ENCAP_IP_OVER_FC:
1462 capture_ipfc(pd, whdr.caplen, &ld->counts);
1464 case WTAP_ENCAP_ARCNET:
1465 capture_arcnet(pd, whdr.caplen, &ld->counts, FALSE, TRUE);
1467 case WTAP_ENCAP_ARCNET_LINUX:
1468 capture_arcnet(pd, whdr.caplen, &ld->counts, TRUE, FALSE);
1470 case WTAP_ENCAP_APPLE_IP_OVER_IEEE1394:
1471 capture_ap1394(pd, 0, whdr.caplen, &ld->counts);
1473 /* XXX - some ATM drivers on FreeBSD might prepend a 4-byte ATM
1474 pseudo-header to DLT_ATM_RFC1483, with LLC header following;
1475 we might have to implement that at some point. */
1479 #endif /* HAVE_LIBPCAP */