wsshuttle

#!/bin/bash

usage(){
    echo -n "${0##*/}"
    echo -n ' [--delete] [--dry] [--help] [--upgrade] [--version]'
    echo -n ' <sshuttle_args...>'
    echo
}
#usage;exit

help(){
    echo USAGE
    echo -n '    '
    usage
    cat<<EOF
DESCRIPTION
    It runs sshuttle from WSL2, and sets up the routing table of Windows.
    Since it modifies the routing table of Windows,
    the admin privilege of Windows is required.
    (Open WSL2 terminal with "Run as Administrator")
OPTIONS
    --delete:       Delete the entries of routing table.
    --dry:          Just print commands to run, don't make any changes.
    --help:         Show this help.
    --upgrade:      Update this program.
    --version:      Show version.
EXAMPLES
    wsshuttle -r ssh-server -x 157.0.0.0/8 0/0
        Route all (0/0) packets through ssh-server except destination is
        157.0.0.0/8. And it excludes 'IP address of ssh-server' too by
        specifying -x 'IP address of ssh-server' automatically.
    wsshuttle -r ssh-server -x 157.0.0.0/8 0/0 --delete
        Deletes the entries of the routing table.
    wsshuttle -r ssh-server -x 157.0.0.0/8 0/0 --dry
        Dry-run, just print commands to run, doesn't make any changes.
EOF
}
#help;exit

show(){
    for rxs in "$@"; do
        eval echo '${'$rxs'[@]}' |
        xargs -n1 echo $rxs: |
        cat
    done
    exit 0
}
#r=aa; x=(bb cc); s=(dd ee); show r x s; exit

parse_args(){
    args=()
    for i in "$@"; do
        if [[ $i = --delete ]]; then
            IS_DELETE=1
        elif [[ $i = --dry ]]; then
            IS_DRY=1
        elif [[ $i = --noresolve ]]; then
            IS_NORESOLVE=1
        else
            args+=("$i")
        fi
    done
    #show IS_DELETE IS_DRY IS_NORESOLVE args

    IS_NORESOLVE=1
    [[ $IS_NORESOLVE = 1 ]] && return

    for((i = 1; i < ${#args[@]}; i++)); do
        if [[ ${args[$i-1]} =~ ^-[^-]*r$ ]]; then # -r
            ssh=$(ssh -v ${args[$i]} true 2>&1 | tr -d '\r' | tr -s ' ')
            break
        fi
    done
    #echo "$ssh";exit

    [[ $i = ${#args[@]} ]] && return

    while true; do
        pc=$(
            echo "$ssh" |
            grep 'Executing proxy command:' |
            cut -d' ' -f6- |
            perl -pe 's/^(ssh.* -[^- ]*)W [^ ]+/\1v/' | # -W %h:%p -> -v
            cat
        )
        #echo ,$pc,
        [[ -z $pc ]] && break
        ssh=$($pc true 2>&1 | tr -d '\r' | tr -s ' ') ||
        { echo error: $pc failed; exit 1; }
    done
    rhost=$(echo "$ssh" | awk -F'[][]' '/Authenticated/{print $2}')
    rip=$(dig +short $rhost | head -n1)
    #show rhost rip
}

set_xs(){
    x=($rip); s=()
    for((i = 1; i < ${#args[@]}; i++)); do
        if [[ ${args[$i-1]} =~ ^-[^-]*x$ ]]; then # -x
            x+=("${args[$i]}")
        elif [[ ! ${args[$i-1]} =~ ^-[^-]*[elr] ]]; then # not -e -l -r
            if [[ ${args[$i]} =~ ^[0-9] ]]; then
                s+=("${args[$i]}")
            fi
        fi
    done
    #show x s # 8.8.8.8[/24]

    f() {
        for i in "$@"; do # 8.8.8.8[/24]
            ipcalc "$i" 32 | # 8.8.8.8[/24] 32
            awk '
                $1=="Netmask:"{mask=$2}
                $1=="Address:"{addr=$2}
                $1=="Network:"{addr=substr($2, 0, index($2, "/") - 1)}
                $0==""{exit}
                END{print addr "/" mask}
            ' |
            cat
        done
    }
    x=( $(f "${x[@]}") )
    s=( $(f "${s[@]}") )
    #show x s # 8.8.8.0/255.255.255.0

    s=($(
        echo "${s[@]}" |
        sed 's,0.0.0.0/0.0.0.0,0.0.0.0/128.0.0.0 128.0.0.0/128.0.0.0,g'
    ))
    #show s

    x=( $(echo "${x[@]}" | xargs -n1 | sort -u) )
    s=( $(echo "${s[@]}" | xargs -n1 | sort -u) )
    #show x s # uniq

    #show x s
}

set_env(){
    WSL2_IP=$(hostname -I | cut -d' ' -f1)

    WIN_VIFIP=$(ip r s default | cut -d' ' -f3)
    WIN_VIFID=$(arp.exe -a -N $WIN_VIFIP | grep -aoPm1 '0x[0-9a-f]+' |
        awk '$0=strtonum($0)')

    GW_IP=$(route.exe print -4 | awk '$1=="0.0.0.0"{print $3}')

    WIN_IFIP=$(route.exe print -4 | awk '$1=="0.0.0.0"{print $4}')
    WIN_IFID=$(arp.exe -a -N $WIN_IFIP | grep -aoPm1 '0x[0-9a-f]+' |
        awk '$0=strtonum($0)')

    #show WSL2_IP WIN_VIFID GW_IP WIN_IFID
}

route_add(){
    for i in "${x[@]}"; do
        addr=${i%%/*}
        mask=${i##*/}
        echo route.exe add $addr mask $mask $GW_IP   metric 1 if $WIN_IFID
    done

    for i in "${s[@]}"; do
        addr=${i%%/*}
        mask=${i##*/}
        echo route.exe add $addr mask $mask $WSL2_IP metric 1 if $WIN_VIFID
    done
}

route_del(){
    for i in "${x[@]}"; do
        addr=${i%%/*}
        mask=${i##*/}
        echo route.exe delete $addr mask $mask
    done

    for i in "${s[@]}"; do
        addr=${i%%/*}
        mask=${i##*/}
        echo route.exe delete $addr mask $mask
    done
}

sshuttle_cmd(){
    printf '%q ' sshuttle -l 0.0.0.0:0 "${args[@]}" ${rip:+-x $rip}
    echo
}

main(){
    if [[ "$*" =~ --help ]];  then
        help
        exit 0
    elif [[ "$*" =~ --version ]];  then
        echo 0.0.8
        exit 0
    elif [[ "$*" =~ --upgrade ]];  then
        url=https://raw.githubusercontent.com/yabeenico/wsshuttle/main/wsshuttle
        (echo wget $url -O "'$0'"; echo chmod +x "'$0'") |
        ([[ "$*" =~ --dry ]] && cat || bash)
        exit 0
    fi

    set_env
    parse_args "$@" # args, rip, IS_DELETE, IS_DRY
    set_xs          # x, s

    if [[ $IS_DELETE = 1 ]]; then
        if [[ $IS_DRY = 1 ]]; then
            route_del | column -t
        else
            route_del | powershell.exe -NonInteractive -NoProfile -
        fi
    else
        if [[ $IS_DRY = 1 ]]; then
            (route_del; route_add) | column -t
            sshuttle_cmd
            route_del | column -t
        else
            route_del | powershell.exe -NonInteractive -NoProfile - &>/dev/null
            route_add | powershell.exe -NonInteractive -NoProfile - |
                grep -av OK
            if [[ $? != 0 ]]; then # if route.exe add success
                trap '
                    route_del |
                    powershell.exe -NonInteractive -NoProfile - &>/dev/null &
                    exit
                ' 2
                trap '
                    route_del |
                    powershell.exe -NonInteractive -NoProfile - &>/dev/null &
                    exit 1
                ' 1 3 15
                sshuttle_cmd
                sshuttle_cmd | bash
                kill $$
            fi
        fi
    fi
}

main "$@"