209 lines
7.5 KiB
C
209 lines
7.5 KiB
C
/* capture_loop.h
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* Do the low-level work of a capture
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/** @file
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*
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* Do the low-level work of a capture.
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*
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*/
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#ifndef __CAPTURE_LOOP_H__
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#define __CAPTURE_LOOP_H__
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#ifndef _WIN32
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/*
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* Get information about libpcap format from "wiretap/libpcap.h".
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* XXX - can we just use pcap_open_offline() to read the pipe?
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*/
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#include "wiretap/libpcap.h"
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#endif
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/** Do the low-level work of a capture.
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* Returns TRUE if it succeeds, FALSE otherwise. */
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extern int capture_loop_start(capture_options *capture_opts, gboolean *stats_known, struct pcap_stat *stats);
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/** Stop a low-level capture (stops the capture child). */
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extern void capture_loop_stop(void);
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/*** the following is internal only (should be moved to capture_loop_int.h) ***/
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#ifndef HAVE_PCAP_BREAKLOOP
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/*
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* We don't have pcap_breakloop(), which is the only way to ensure that
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* pcap_dispatch(), pcap_loop(), or even pcap_next() or pcap_next_ex()
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* won't, if the call to read the next packet or batch of packets is
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* is interrupted by a signal on UN*X, just go back and try again to
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* read again.
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*
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* On UN*X, we catch SIGUSR1 as a "stop capturing" signal, and, in
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* the signal handler, set a flag to stop capturing; however, without
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* a guarantee of that sort, we can't guarantee that we'll stop capturing
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* if the read will be retried and won't time out if no packets arrive.
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*
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* Therefore, on at least some platforms, we work around the lack of
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* pcap_breakloop() by doing a select() on the pcap_t's file descriptor
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* to wait for packets to arrive, so that we're probably going to be
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* blocked in the select() when the signal arrives, and can just bail
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* out of the loop at that point.
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*
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* However, we don't want to that on BSD (because "select()" doesn't work
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* correctly on BPF devices on at least some releases of some flavors of
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* BSD), and we don't want to do it on Windows (because "select()" is
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* something for sockets, not for arbitrary handles). (Note that "Windows"
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* here includes Cygwin; even in its pretend-it's-UNIX environment, we're
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* using WinPcap, not a UNIX libpcap.)
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*
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* Fortunately, we don't need to do it on BSD, because the libpcap timeout
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* on BSD times out even if no packets have arrived, so we'll eventually
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* exit pcap_dispatch() with an indication that no packets have arrived,
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* and will break out of the capture loop at that point.
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*
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* On Windows, we can't send a SIGUSR1 to stop capturing, so none of this
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* applies in any case.
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*
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* XXX - the various BSDs appear to define BSD in <sys/param.h>; we don't
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* want to include it if it's not present on this platform, however.
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*/
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# if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__) && \
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!defined(__bsdi__) && !defined(__APPLE__) && !defined(_WIN32) && \
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!defined(__CYGWIN__)
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# define MUST_DO_SELECT
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# endif /* avoid select */
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#endif /* HAVE_PCAP_BREAKLOOP */
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typedef void (*capture_packet_cb_fct)(u_char *, const struct pcap_pkthdr *, const u_char *);
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/* moved from capture_loop.c here, so we can combine it (and the related functions) with twireshark */
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/* XXX - should be moved back to capture_loop.c */
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/* E: capture_loop.c only (Wireshark/dumpcap) T: twireshark only */
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typedef struct _loop_data {
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/* common */
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gboolean go; /* TRUE as long as we're supposed to keep capturing */
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int err; /* E: if non-zero, error seen while capturing */
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gint packet_count; /* Number of packets we have already captured */
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gint packet_max; /* E: Number of packets we're supposed to capture - 0 means infinite */
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jmp_buf stopenv; /* T: starting point of loop (jump back this point on SIG...) */
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char *save_file; /* T: Name of file to which we're writing */
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capture_packet_cb_fct packet_cb; /* callback for a single captured packet */
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/* pcap "input file" */
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pcap_t *pcap_h; /* pcap handle */
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gboolean pcap_err; /* E: TRUE if error from pcap */
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#ifdef MUST_DO_SELECT
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int pcap_fd; /* pcap file descriptor */
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#endif
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/* capture pipe (unix only "input file") */
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gboolean from_cap_pipe; /* TRUE if we are capturing data from a capture pipe */
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#ifndef _WIN32
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struct pcap_hdr cap_pipe_hdr; /* ? */
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struct pcaprec_modified_hdr cap_pipe_rechdr; /* ? */
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int cap_pipe_fd; /* the file descriptor of the capture pipe */
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gboolean cap_pipe_modified; /* TRUE if data in the pipe uses modified pcap headers */
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gboolean cap_pipe_byte_swapped; /* TRUE if data in the pipe is byte swapped */
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unsigned int cap_pipe_bytes_to_read;/* Used by cap_pipe_dispatch */
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unsigned int cap_pipe_bytes_read; /* Used by cap_pipe_dispatch */
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enum {
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STATE_EXPECT_REC_HDR,
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STATE_READ_REC_HDR,
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STATE_EXPECT_DATA,
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STATE_READ_DATA
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} cap_pipe_state;
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enum { PIPOK, PIPEOF, PIPERR, PIPNEXIST } cap_pipe_err;
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#endif
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/* output file */
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FILE *pdh;
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int linktype;
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gint wtap_linktype;
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long bytes_written;
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} loop_data;
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/** init the capture filter */
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typedef enum {
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INITFILTER_NO_ERROR,
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INITFILTER_BAD_FILTER,
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INITFILTER_OTHER_ERROR
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} initfilter_status_t;
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extern initfilter_status_t
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capture_loop_init_filter(pcap_t *pcap_h, gboolean from_cap_pipe, const gchar * iface, gchar * cfilter);
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#ifdef HAVE_LIBPCAP
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#ifndef _WIN32
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extern int
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cap_pipe_dispatch(loop_data *, guchar *, char *, int);
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#endif /* _WIN32 */
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#endif
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extern gboolean
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capture_loop_open_input(capture_options *capture_opts, loop_data *ld,
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char *errmsg, size_t errmsg_len,
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char *secondary_errmsg, size_t secondary_errmsg_len);
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extern gboolean
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capture_loop_open_output(capture_options *capture_opts, int *save_file_fd, char *errmsg, int errmsg_len);
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extern gboolean
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capture_loop_init_output(capture_options *capture_opts, int save_file_fd, loop_data *ld, char *errmsg, int errmsg_len);
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extern gboolean
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capture_loop_close_output(capture_options *capture_opts, loop_data *ld, int *err_close);
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/*
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* Routines called by the capture loop code to report things.
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*/
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/** Report a new capture file having been opened. */
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extern void
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report_new_capture_file(const char *filename);
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/** Report a number of new packets captured. */
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extern void
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report_packet_count(int packet_count);
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/** Report the packet drops once the capture finishes. */
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extern void
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report_packet_drops(int drops);
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/** Report an error in the capture. */
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extern void
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report_capture_error(const char *error_msg, const char *secondary_error_msg);
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/** Report an error with a capture filter. */
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extern void
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report_cfilter_error(const char *cfilter, const char *errmsg);
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#endif /* capture_loop.h */
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