#!/bin/bash
# trigger.sh

myip() {
    ip addr \
        | grep 192 \
        | sed 's/^ *//' \
        | cut -d\  -f 2 \
        | cut -d/  -f 1
}

user=joe
use_tcpdump=true
use_nc_proxy=false
delay=2
verbose=false
out=out/$(date +%Y%m%d-%H%M%S)
srv_port=1234
srv_host=$(myip)


while true ; do
    case "$1" in
        -o) out="$2"; shift 2
            ;;
        -u) user="$2"; shift 2
            ;;
        -h) srv_host="$2"; shift 2
            ;;
        -p) srv_port="$2"; shift 2
            ;;
        -P) pxy_port="$2"; shift 2
            ;;
        -d) delay="$2"; shift 2
            ;;
        -t) use_tcpdump=true; shift 1
            ;;
        -T) use_tcpdump=false; shift 1
            ;;
        -n) use_nc_proxy=true; shift 1
            ;;
        -N) use_nc_proxy=false; shift 1
            ;;
        -v) verbose=true; shift 1
            ;;
        --) shift 1
            break;
            ;;
        *)  break;
            ;;
    esac
done


tmp=$(mktemp -d)
mkdir -p $out

start_tcpdump() {
    local pcap=$out/traffic.pcap
    echo starting tcpdump
    yum -q -y install tcpdump &>/dev/null
    tcpdump -i any -w $pcap "port $srv_port" \
        &
}

start_nc_proxy() {
    local pxy_port=$(($srv_port - 1))
    local back=$tmp/back
    local sent=$out/sent
    local rcvd=$out/rcvd
    echo starting proxy
    mkfifo $back
    cat < $back \
        | nc -k -l -p $pxy_port \
        | tee $sent \
        | nc $srv_host $srv_port \
        | tee $rcvd \
        > $back \
        &
}

trigger() {
    echo adding + removing $user
    useradd $user
    userdel -r $user
}

$use_tcpdump && start_tcpdump
$use_nc_proxy && start_nc_proxy

sleep $delay

trigger

echo cleaning up
$use_nc_proxy && killall ncat
$use_tcpdump && killall tcpdump
rm -rf $tmp