Wireless sniffing on OS X with channel hopping.

sniff.sh

#!/usr/bin/env bash

duration=$1

sudo chmod o+r /dev/bpf*
echo "> Enabled sniffing on all interfaces."

networksetup -listallhardwareports
device=`networksetup -listallhardwareports | grep -A1 'Wi-Fi' | grep 'Device' | cut -d':' -f2 | xargs`
echo "> Using device $device."

networksetup -setairportpower $device on
echo "> Enabled power on device $device."

airport="/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport"
if [ -e $airport ]; then echo "Airport is available."; else echo "Airport is not available."; fi

sudo $airport -z
echo "> Dissociating from current wireless network."

echo "> Generating filename."
randhex=`cat /dev/urandom | env LC_CTYPE=C tr -dc '0-9A-F' | fold -w 6 | head -n 1`
filename="dump-$duration-$randhex.pcap"
echo "> Using filename $filename."

sudo tcpdump -i $device -I -s 0 -B 524288 -w $filename &
echo "> Started capture with tcpdump for $duration minute(s)."
sleep 1

for i in `seq 1 $duration`
do
	echo "> Hopping through 36 channels ($i/$duration)"
	for channel in 1 2 3 4 5 6 7 8 9 10 11 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140 144 149 153 157 161 165
	do
		echo -n "$channel "
		sudo $airport --channel=$channel
		sleep 1.667 # 36 channels in 60 seconds
	done
	echo ""
done

echo "> Done looping stopping sniffing."

sudo killall tcpdump
echo "> Done sniffing. Resetting airport."

networksetup -setairportpower $device off
networksetup -setairportpower $device on
echo "> Airport reset."