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op-packages/luci-app-packet-capture/root/usr/libexec/packet_capture_start
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#!/bin/sh
. /usr/share/libubox/jshn.sh
PIDFILE="/var/run/packet_capture.pid"
WORKDIR="/var/run/packet_capture"
FILTERFILE="$WORKDIR/tcpdump_filter"
PCAPFILE="$WORKDIR/capture.pcap"
if [ -f "$PIDFILE" ]; then
echo "error: Packet capture is running"
exit 1
fi
mkdir -p "$WORKDIR"
chmod 0700 "$WORKDIR"
json_load "$1"
json_get_var interface interface
json_get_var filter filter
json_get_var duration duration
json_get_var packets packets
json_get_var verbose verbose
json_get_var domains domains
json_get_var file file
args="-n"
if [ "$domains" = "1" ];then
args=""
fi
if [ -n "$interface" ];then
case "$interface" in
*[!A-Za-z0-9_.:-]*)
echo "error: Incorrect format of an interface"
exit 1
;;
esac
ip a show "$interface" > /dev/null 2>&1
if [ "$?" -ne 0 ]; then
echo "error: Incorrect format of an interface"
exit 1
fi
args="$args -i $interface"
fi
if [ -n "$packets" ];then
echo "$packets" | egrep '^[0-9]+$' >/dev/null
if [ "$?" -eq 0 ];then
args="$args -c $packets"
else
echo "error: Incorrect packets argument"
exit 1
fi
fi
if [ -n "$duration" ];then
echo "$duration" | egrep '^[0-9]+$' >/dev/null
if [ "$?" -ne 0 ];then
echo "error: Incorrect duration argument"
exit 1
fi
fi
if [ "$verbose" = "1" ];then
args="$args -e"
fi
if [ "$file" = "1" ];then
mem=$(awk '/MemTotal/ {print $2}' /proc/meminfo)
args="$args -W 2 -C $((mem/(1024 * 10))) -w $PCAPFILE -z /usr/libexec/packet_capture_stop"
fi
if [ -n "$filter" ];then
tcpdump -i lo -d "$filter" >/dev/null 2>/dev/null
if [ $? -eq 1 ];then
echo "error: Incorrect filter argument"
exit 1
fi
( umask 077; printf '%s\n' "$filter" > "$FILTERFILE" )
fi
(/usr/libexec/packet_capture "$args" "$duration")&
echo $! > /var/run/packet_capture.pid
exit 0