makeOpenWrtConfig.sh

#!/bin/sh
# vim:set tabstop=8 shiftwidth=4 expandtab:
# kate: space-indent on; indent-width 4;
#
# Copyright (C) 2017 WEARENOTALONE
#
# Helper script for OpenWrt/LEDE configuration
# References:
#  https://www.reddit.com/r/openwrt/comments/515oea/finally_got_80211r_roaming_working/
#  https://forum.openwrt.org/viewtopic.php?id=56546
#  https://wiki.openwrt.org/doc/uci/wireless
#  https://w1.fi/cgit/hostap/plain/hostapd/hostapd.conf

set -e
#set -x

prg=$(basename "$0")

version() {
    cat << ____EOF
$prg version 0.1
Copyright (C) 2017 WEARENOTALONE
____EOF
}

help() {
    cat << ____EOF
Usage: $prg [OPTIONS] COMMAND [arg...]
       $prg [ --help | -v | --version ]

A helper script for OpenWrt/LEDE configuration.

Options:

  -h, --help                      Print usage
  -v, --version                   Print version information and quit

Commands:
    _80211r    802.11r fast BSS transition (FT)
    bitrates   Minimum wifi bitrates
    help       Print usage

____EOF
}

stderr() {
    local _msg
    while read -r _msg
    do
        echo $_msg 2>&1
    done
}

error() {
    stderr << ____EOF
ERROR: $*
____EOF
}

warn() {
    stderr << ____EOF
WARN: $*
____EOF
}

_80211r() {
    help() {
        cat << ________EOF
Usage:  $prg _80211r [OPTIONS]

Print configuration for 802.11r fast BSS transition (FT)

Options:
      --debug                         Print commands issued by $prg
      --mobility-domain [FFFF]        Provide a 4-character Hex string as mobility domain
                                      If no argument is given, a random string is generated
      --passphrase [FF..FF]           Provide a 32-character Hex string as passphrase for inter-AP communication
                                      If no argument is given, a random string is generated
      --bssids XX:..:XX,XX:..:XX,...  Provide BSSIDs of all involved APs as a comma-seperated list
      -h, --help                      Print usage
________EOF
    }

    local _mobility_domain=""
    local _passphrase=""
    local _bssids=""
    local _debug=""

    if [ -z "$1" ]; then
        help
        return 0
    fi

    while [ -n "$1" ]; do
        case "$1" in
            "--debug")
                _debug="yes"
                ;;
            "--mobility-domain")
                if [ -z "$2" ]; then
                    error "flag is missing arg: --mobility-domain"
                    return 255
                fi
                
                if [ -n "$_mobility_domain" ]; then
                    error "flag already set: --mobility-domain"
                    return 255
                fi
                
                _mobility_domain="$2"
                shift
                ;;
            "--passphrase")
                if [ -z "$2" ]; then
                    error "flag is missing arg: --passphrase"
                    return 255
                fi
                
                if [ -n "$_passphrase" ]; then
                    error "flag already set: --passphrase"
                    return 255
                fi
                
                _passphrase="$2"
                shift
                ;;
            "--bssids")
                if [ -z "$2" ]; then
                    error "flag is missing arg: --bssids"
                    return 255
                fi
                
                if [ -n "$_bssids" ]; then
                    error "flag already set: --bssids"
                    return 255
                fi
                
                _bssids="$2"
                shift
                ;;
            "-h"|"--help")
                help
                return 0
                ;;
            -*|*)
                error "unknown flag: $1"
                return 255
                ;;
        esac
        shift
    done

    if [ -z "$_bssids" ]; then
        error "No BSSIDs given"
        return 255
    fi
    
    if [ -z "$_mobility_domain" ]; then
        _mobility_domain="$(openssl rand -hex 2)"
    elif ! echo "$_mobility_domain" | grep -Eq ^[A-Fa-f0-9]{4}$; then
        error "Mobility domain is not a 4-character Hex string"
        return 255
    fi
    
    if [ -z "$_passphrase" ]; then
        _passphrase="$(openssl rand -hex 16)"
    elif ! echo "$_passphrase" | grep -Eq ^[A-Fa-f0-9]{32}$; then
        error "Passphrase is not a 32-character Hex string"
        return 255
    fi
    
    _bssids="$(echo $_bssids | sed -e 's/,/ /g')"
    
    for _bssid in $_bssids; do
        if ! echo "$_bssid" | grep -Eq '^([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$'; then
            error "'$_bssid' is not a valid BSSID"
            return 255
        fi
    done
    
    (
    [ "$_debug" = "yes" ] && set -x
    
    local _r0kh=""
    local _r1kh=""
    for _bssid in $_bssids; do
        local _nasid="$(echo $_bssid | sed -e 's/://g')"
        local _r1_key_holder="$_bssid"
        _r0kh="${_r0kh}${_bssid},${_nasid},${_passphrase} "
        _r1kh="${_r1kh}${_bssid},${_r1_key_holder},${_passphrase} "
    done
    
    for _bssid in $_bssids; do
        local _nasid="$(echo $_bssid | sed -e 's/://g')"
        local _r1_key_holder="$_bssid"
        
        cat << ________EOF
config wifi-iface 'radio'
    ...
    option ieee80211r '1'
    option pmk_r1_push '1'
    option wpa_disable_eapol_key_retries '1'
    option mobility_domain '$_mobility_domain'
    option nasid '$_nasid'
    option r1_key_holder '$_r1_key_holder'
$(for _ in $_r0kh; do echo "    list r0kh '$_'"; done)
$(for _ in $_r1kh; do echo "    list r1kh '$_'"; done)

________EOF
    done
    
    )
}

bitrates() {
    help() {
        cat << ________EOF
Usage:  $prg bitrates [OPTIONS]

Print configuration for setting minimum wifi bitrates, impacting only on legacy rates.
High throughput (HT) and Very high throughput (VHT) rates are not affected.

Options:
      --debug               Print commands issued by $prg
      --protocol CODE       Provide supported wifi protocol, valid codes are:
                            code | wifi protocol          | bitrates (Mbps)
                            -----|------------------------|----------------------------------
                               g | IEEE 802.11g (2.4 GHz) | 1 2 5.5 11 6 9 12 18 24 36 48 54
                               b | IEEE 802.11b (2.4 GHz) | 1 2 5.5 11
      --minimum-rate RATE   Provide minimum wifi rate in Mbps
      -h, --help            Print usage
________EOF
    }
    
    local _protocol=""
    local _minimum_rate=""
    local _debug=""

    if [ -z "$1" ]; then
        help
        return 0
    fi
    
    while [ -n "$1" ]; do
        case "$1" in
            "--debug")
                _debug="yes"
                ;;
            "--protocol")
                if [ -z "$2" ]; then
                    error "flag is missing arg: --protocol"
                    return 255
                fi
                
                if [ -n "$_protocol" ]; then
                    error "flag already set: --protocol"
                    return 255
                fi
                
                _protocol="$2"
                shift
                ;;
            "--minimum-rate")
                if [ -z "$2" ]; then
                    error "flag is missing arg: --minimum-rate"
                    return 255
                fi
                
                if [ -n "$_minimum_rate" ]; then
                    error "flag already set: --minimum-rate"
                    return 255
                fi
                
                _minimum_rate="$2"
                shift
                ;;
            "-h"|"--help")
                help
                return 0
                ;;
            -*|*)
                error "unknown flag: $1"
                return 255
                ;;
        esac
        shift
    done
    
    if [ -z "$_protocol" ]; then
        error "No supported wifi protocol given"
        return 255
    elif [ "$_protocol" != b ] && [ "$_protocol" != g ]; then
        error "$_protocol is not a valid wifi protocol"
        return 255
    fi
    
    if [ -z "$_minimum_rate" ]; then
        error "No minimum rate given"
        return 255
    elif ! echo "$_minimum_rate" | grep -Eq '^[0-9]+(.[0-9]*)*$'; then
        error "$_minimum_rate is not a valid rate"
        return 255
    fi
    local _minimum_rate="$(expr "$_minimum_rate" \* 10)"
    
    (
    [ "$_debug" = "yes" ] && set -x
    
    case "$_protocol" in 
        b)
            local _bitrates="10 20 55 110"
            ;;
        g)
            local _bitrates="10 20 55 110 60 90 120 180 240 360 480 540"
            ;;
    esac
    
    local _supported_rates="$(for _ in $_bitrates; do echo -n "${_}00 "; done)"
    local _basic_rate="$(for _ in $_bitrates; do if [ "$_" -ge "$_minimum_rate" ]; then echo -n "${_}00 "; fi; done)"
    
    _supported_rates="$(echo $_supported_rates | sed -e 's/ $//g' )"
    _basic_rate="$(echo $_basic_rate | sed -e 's/ $//g' )"
    
    cat << ____EOF

config wifi-device 'radio'
    #ensure that your device uses
    # option hwmode '11g'
    #or
    # option hwmode '11b'
    ...
    
    list supported_rates '$_supported_rates'
    list basic_rate '$_basic_rate'
    
____EOF
    
    )
}

if [ $# -eq 0 ]; then
    help
    exit 1
fi

while [ -n "$1" ]; do
    case "$1" in
        "_80211r"|"bitrates"|"help")
            ("$@")
            exit $?
            ;;
        "-v"|"--version")
            version
            exit 0
            ;;
        "-h"|"--help")
            help
            exit 0
            ;;
        -*)
            error "unknown flag: $1"
            exit 1
            ;;
        *)
            error "unknown command: $1"
            exit 1
            ;;
    esac
    shift
done

exit $?