273 lines
6.5 KiB
Bash
Executable File
273 lines
6.5 KiB
Bash
Executable File
#!/bin/sh
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#
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# capture-sample.sh, Copyright © 2011 Matteo Cypriani <mcy@lm7.fr>
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#
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########################################################################
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# This program is licensed under the terms of the Expat license.
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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########################################################################
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#
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# Captures a few packets on a Wi-Fi interface, using Tcpdump, and
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# writes them to a Pcap file along with some information about the
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# system. A tarball containing all these files is finally created.
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#set -x
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set -e
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## Parameters (tune them if you want) ##
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# Number of packet to capture:
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NB_PKT=10
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# Maximal time of a capture on a given channel:
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TIMEOUT=15
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# Temporary directory:
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TMP=/tmp
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# Name of the capture file:
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FILE=capture.pcap
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# First channel to scan:
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CHANNEL=1
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## Functions ##
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# Displays the message in argument on the error output and exits
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error()
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{
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printf '%s\n' "$1" >&2
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clean
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exit 1
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}
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# Deletes the temporary files
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clean()
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{
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rm -fr "$DESTDIR"
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}
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# Verifies the presence of the needed programs
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check_dependencies()
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{
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command -v tcpdump >/dev/null \
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|| error "tcpdump is required to run this program!"
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if [ "$OS" = Linux ] ; then
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[ -x /sbin/iwconfig ] \
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|| error "iwconfig is required to run this program on Linux!"
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fi
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}
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# Switches the capture interface to monitor mode, on the channel in
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# argument
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iface_set_channel()
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{
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echo "Setting interface $IFACE on channel $1..."
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case "$OS" in
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Linux)
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iface_down
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iwconfig "$IFACE" mode managed
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iface_up
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iwconfig "$IFACE" channel "$1"
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;;
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NetBSD | OpenBSD)
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iface_down
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ifconfig "$IFACE" media autoselect chan "$1"
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iface_up
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;;
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*)
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error "Your OS is not supported."
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;;
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esac \
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|| error "Cannot set the channel!"
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echo "Channel set."
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iface_monitor
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}
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# Switches the capture interface to monitor mode
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iface_monitor()
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{
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iface_down
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printf 'Switching interface %s to monitor mode... ' "$IFACE"
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case "$OS" in
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Linux)
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iwconfig "$IFACE" mode monitor
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;;
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NetBSD | OpenBSD)
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ifconfig "$IFACE" media autoselect mediaopt monitor
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;;
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*)
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error "Your OS is not supported."
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;;
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esac \
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|| error "Cannot switch the interface to monitor mode!"
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echo "OK."
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iface_up
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}
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# Shuts down the capture interface
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iface_down()
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{
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printf 'Shuting down interface %s... ' "$IFACE"
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ifconfig "$IFACE" down \
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|| error "Cannot shut down the interface!"
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echo "OK."
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}
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# Turns on the capture interface
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iface_up()
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{
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printf 'Turning up interface %s... ' "$IFACE"
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ifconfig "$IFACE" up \
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|| error "Cannot turn the interface up!"
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echo "OK."
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}
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# Invokes tcpdump and displays the number of packets captured
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invoke_tcpdump()
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{
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NCAP=$(tcpdump -i "$IFACE" -c "$NB_PKT" -w "$FILE" 2>&1 \
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| sed -nr 's/([[:digit:]]+) packets received by filter$/\1/p')
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[ -z "$NCAP" ] \
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&& error "Error parsing the tcpdump messages! (NCAP=\"$NCAP\")"
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echo "$NCAP"
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}
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# Waits for a number of seconds, then kills any tcpdump process
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wait_tcpdump()
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{
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sleep "$1"
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echo "$1 seconds passed, killing all tcpdump processes..."
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pkill tcpdump
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}
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# Gets some information about the running system
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gather_system_information()
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{
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printf "Gathering system information... "
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# Kernel & other information:
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uname -a >"$DESTDIR"/uname-a
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# Wi-Fi interface information:
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ifconfig "$IFACE" >"$DESTDIR/ifconfig_$IFACE"
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[ "$OS" = Linux ] \
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&& iwconfig "$IFACE" >"$DESTDIR/iwconfig_$IFACE"
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# PCI devices:
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command -v lspci >/dev/null \
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&& lspci >"$DESTDIR"/lspci \
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|| echo "lspci not available! Please install pciutils. "
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# USB devices:
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gather_usb_devices
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# Loaded kernel modules:
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gather_kernel_modules
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echo "OK."
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}
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# Gets information about the plugged usb devices
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gather_usb_devices()
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{
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case "$OS" in
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Linux)
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command -v lsusb >/dev/null \
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&& lsusb >"$DESTDIR"/lsusb \
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|| echo "lsusb not available! Please install usbutils. "
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;;
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NetBSD | OpenBSD | DragonFly)
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command -v usbstats >/dev/null \
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&& usbstats >"$DESTDIR"/usbstats \
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|| echo "usbstats not available! Please install usbutil. "
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;;
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esac
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}
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# Gets information about the loaded kernel modules
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gather_kernel_modules()
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{
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case "$OS" in
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Linux)
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lsmod >"$DESTDIR"/lsmod
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;;
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NetBSD | OpenBSD)
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modstat >"$DESTDIR"/modstat
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;;
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DragonFly)
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kldstat >"$DESTDIR"/kldstat
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;;
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esac
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}
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# Compresses the destination directory to a tarball
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create_archive()
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{
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TARBALL="${DESTDIR}.tar.gz"
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DIR=$(basename "$DESTDIR")
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tar -C "$TMP" -czf "$TARBALL" "$DIR"
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echo "Archive \"$TARBALL\" created."
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}
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## Main program ##
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[ $# -eq 1 ] \
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|| error "Usage: $0 <wifi_interface>"
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# Interface to capture from:
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IFACE=$1
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# Machine information:
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OS=$(uname)
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OS_RELEASE=$(uname -r)
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HOSTNAME=$(uname -n)
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# Current date:
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DATE=$(date +%FT%H%M%S)
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# Temporary destination directory:
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DESTDIR=$(mktemp -d \
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"$TMP/capture_${OS}-${OS_RELEASE}_${IFACE}_${HOSTNAME}_${DATE}_XXX")
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# Update capture file with full path:
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FILE="$DESTDIR/$FILE"
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check_dependencies
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echo "Trying to capture $NB_PKT packets..."
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CAPTURED=0
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while [ "$CAPTURED" -eq 0 ] && [ "$CHANNEL" -le 14 ] ; do
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echo
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iface_set_channel "$CHANNEL"
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wait_tcpdump "$TIMEOUT" &
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CAPTURED=$(invoke_tcpdump)
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[ "$CAPTURED" -eq 0 ] \
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&& echo "No packet captured on channel $CHANNEL." \
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|| echo "$CAPTURED packets captured on channel $CHANNEL."
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CHANNEL=$((CHANNEL + 1))
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done
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echo
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[ "$CAPTURED" -gt 0 ] \
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|| error "Failed to capture any packet!"
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echo "Capture file \"$FILE\" created."
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gather_system_information
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create_archive
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clean
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printf '\nYou can now shut down the interface %s if you would like:\n' "$IFACE"
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printf '\tifconfig %s down\n' "$IFACE"
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