RIOT/dist/tools/tapsetup/tapsetup

#!/bin/sh

PROGRAM=$(basename $0)
COUNT="2"
COMMAND=""
BRNAME="tapbr0"
TAPNAME="tap"
TUNNAME=""
DEACTIVATE_IPV6=""
ENABLE_FORWARDING=0
BRIDGE_ADDRS=""
BRIDGE_ROUTES=""
DEFAULT_PREFIX_LEN=128
UPLINK=""

usage() {
    echo "usage: ${PROGRAM} [arguments]" >&2
    echo "" >&2
    echo "Defaults:"
    echo "   If no option is given, -c is assumed" >&2
    echo "" >&2
    echo "Options:" >&2
    echo "   -c [<num>], --create [<num>]: Create <num> tap interfaces (default: 2)" >&2
    echo "   -d, --delete:                 Delete all interface" >&2
    echo "   -l <iface>, --list <iface>:   If <iface> belongs to a bridge, list the bridge and" >&2
    echo "                                 all interfaces that belong to it. If <iface> does " >&2
    echo "                                 not belong to a bridge, just print <iface>." >&2
    echo "   -a <address>[/<prefix_len>], --address <address>[/<prefix_len>]:" >&2
    echo "                                 Address to add to the created bridge. Can be used" >&2
    echo "                                 multiple times." >&2
    echo "   -r <route>[/<prefix_len>] <next_hop>, --route <route>[/<prefix_len>] <next_hop>:" >&2
    echo "                                 Route to add to via the created bridge. Can be used" >&2
    echo "                                 multiple times." >&2
    echo "   -f, --forwarding              Enable forwarding system-wide on creation and " >&2
    echo "                                 disable on deletion." >&2
    echo "   --tun [<name>]                Create a single, unbridged TUN interface" >&2
    echo "                                 named <name>0 (default for <name>: tun)." >&2
    echo "                                 No bridge will be created in that case." >&2
    echo "                                 <name> will be ignored on OSX and FreeBSD." >&2
    echo "   -b <name>, --bridge <name>:   Give name for the bridge (default: tapbr)" >&2
    echo "   -t <name>, --tap <name>:      Name base for the tap interfaces; the" >&2
    echo "                                 generated names will be <name>x" >&2
    echo "                                 (default: tap; ignored on OSX and FreeBSD)" >&2
    echo "   -6, --deactivate-ipv6:        Deactivate IPv6 for the interfaces and bridge" >&2
    echo "                                 (ignored on OSX and FreeBSD)" >&2
    echo "   -u, --uplink:                 Optional uplink interface" >&2
    echo "                                 (ignored on OSX and FreeBSD)" >&2
    echo "   -h, --help:                   Prints this text" >&2
}

unsupported_platform() {
    echo "unsupported platform" >&2
    echo "(currently supported \`uname -s\` 'Darwin', 'FreeBSD', and 'Linux')" >&2
}

update_uplink() {
    if command -v dhclient > /dev/null; then
        dhclient $1
    else
        echo "DHCP client \`dhclient\` not found." >&2
        echo "Please reconfigure your DHCP client for interface $1" >&2
        echo "to keep up-link's IPv4 connection." >&2
    fi
}

activate_forwarding() {
    if [ ${ENABLE_FORWARDING} -eq 1 ]; then
        case "${PLATFORM}" in
            FreeBSD|OSX)
                sysctl -w net.inet.ip.forwarding=1 || exit 1 ;;
            Linux)
                sysctl -w net.ipv6.conf.${BRNAME}.forwarding=1 || exit 1
                if [ -z ${TUNNAME} ]; then
                    sysctl -w net.ipv6.conf.${BRNAME}.accept_ra=0 || exit 1
                else
                    echo "Setting accept_ra=2 for all interfaces!" >&2
                    # See https://github.com/RIOT-OS/RIOT/issues/14689#issuecomment-668500682
                    for iface in $(ip link | grep -o "^[0-9]\+: [^:]\+" | cut -f2 -d' '); do
                        sysctl -w net.ipv6.conf.${iface}.accept_ra=2 || exit 1
                    done
                fi
                sysctl -w net.ipv6.conf.all.forwarding=1 || exit 1 ;;
            *)  ;;
        esac
    fi
}

add_ipv6_addrs() {
    for a in ${BRIDGE_ADDRS}; do
        address_addr=$(echo "${a}" | cut -d/ -f1)
        prefix_len=$(echo "${a}" | cut -d/ -f2)
        if [ "${a}" = "${prefix_len}" ]; then
            # prefix length is not defined
            prefix_len=${DEFAULT_PREFIX_LEN}
        fi
        case "${PLATFORM}" in
            FreeBSD|OSX)
                ifconfig ${BRNAME} inet6 ${address_addr} prefixlen ${prefix_len} || exit 1
                ;;
            Linux)
                ip address add ${address_addr}/${prefix_len} dev ${BRNAME} || exit 1
                ;;
            *)  ;;
        esac
    done
}

add_ipv6_routes() {
    for r in ${BRIDGE_ROUTES}; do
        route=$(echo "${r}" | cut -d- -f1)
        next_hop=$(echo "${r}" | cut -d- -f2)
        route_prefix=$(echo "${route}" | cut -d/ -f1)
        route_prefix_len=$(echo "${route}" | cut -d/ -f2)
        if [ "${route}" = "${route_prefix_len}" ]; then
            # prefix length is not defined
            route_prefix_len=${DEFAULT_PREFIX_LEN}
        fi
        case "${PLATFORM}" in
            FreeBSD|OSX)
                route -6n add ${route_prefix} -interface ${BRNAME} \
                    ${next_hop} || exit 1
                ;;
            Linux)
                ip route add ${route_prefix}/${route_prefix_len} \
                    via ${next_hop} dev ${BRNAME} || exit 1
                ;;
            *)  ;;
        esac
    done
}

create_bridge() {
    echo "creating bridge ${BRNAME}"

    case "${PLATFORM}" in
        FreeBSD)
            kldload if_bridge       # module might be already loaded => error
            ifconfig ${BRNAME} create || exit 1 ;;
        Linux)
            ip link add name ${BRNAME} type bridge || exit 1
            if [ -n "${UPLINK}" ]; then
                echo "using uplink ${UPLINK}"
                ip link set dev ${UPLINK} master ${BRNAME} || exit 1
            fi
            if [ -n "${DEACTIVATE_IPV6}" ]; then
                echo 1 > /proc/sys/net/ipv6/conf/${BRNAME}/disable_ipv6 || exit 1
            fi ;;
        OSX)
            ifconfig ${BRNAME} create || exit 1 ;;
        *)
            ;;
    esac
}

up_bridge() {
    case "${PLATFORM}" in
        FreeBSD|OSX)
            ifconfig ${BRNAME} up || exit 1 ;;
        Linux)
            ip link set ${BRNAME} up || exit 1

            # The bridge is now the new uplink
            if [ -n "${UPLINK}" ]; then
                update_uplink ${BRNAME}
            fi ;;
        *)
            ;;
    esac
}

deactivate_forwarding() {
    if [ ${ENABLE_FORWARDING} -eq 1 ]; then
        case "${PLATFORM}" in
            FreeBSD|OSX)
                sysctl -w net.inet.ip.forwarding=0 || exit 1 ;;
            Linux)
                sysctl -w net.ipv6.conf.${BRNAME}.forwarding=0 || exit 1
                if [ -z ${TUNNAME} ]; then
                    sysctl -w net.ipv6.conf.${BRNAME}.accept_ra=1 || exit 1
                else
                    echo "Setting accept_ra=1 for all interfaces!" >&2
                    # See https://github.com/RIOT-OS/RIOT/issues/14689#issuecomment-668500682
                    for iface in $(ip link | grep -o "^[0-9]\+: [^:]\+" | cut -f2 -d' '); do
                        sysctl -w net.ipv6.conf.${iface}.accept_ra=1 || exit 1
                    done
                fi
                sysctl -w net.ipv6.conf.all.forwarding=0 || exit 1 ;;
            *)  ;;
        esac
    fi
}

del_ipv6_addrs() {
    for a in ${BRIDGE_ADDRS}; do
        address_addr=$(echo "${a}" | cut -d/ -f1)
        prefix_len=$(echo "${a}" | cut -d/ -f2)
        if [ "${a}" = "${prefix_len}" ]; then
            # prefix length is not defined
            prefix_len=${DEFAULT_PREFIX_LEN}
        fi
        case "${PLATFORM}" in
            FreeBSD|OSX)
                ifconfig ${BRNAME} inet6 ${address_addr} prefixlen ${prefix_len} delete || exit 1
                ;;
            Linux)
                ip address delete ${address_addr}/${prefix_len} dev ${BRNAME} || exit 1
                ;;
            *)  ;;
        esac
    done
}

del_ipv6_routes() {
    for r in ${BRIDGE_ROUTES}; do
        route=$(echo "${r}" | cut -d- -f1)
        next_hop=$(echo "${r}" | cut -d- -f2)
        route_prefix=$(echo "${route}" | cut -d/ -f1)
        route_prefix_len=$(echo "${route}" | cut -d/ -f2)
        if [ "${route}" = "${route_prefix_len}" ]; then
            # prefix length is not defined
            route_prefix_len=${DEFAULT_PREFIX_LEN}
        fi
        case "${PLATFORM}" in
            FreeBSD|OSX)
                route -6 delete ${route_prefix}/${route_prefix_len} \
                    -interface ${BRNAME} ${next_hop} || exit 1
                ;;
            Linux)
                ip route delete ${route_prefix}/${route_prefix_len} \
                    via ${next_hop} dev ${BRNAME} || exit 1
                ;;
            *)  ;;
        esac
    done
}

delete_iface() {
    IFACE="$1"
    echo "deleting ${IFACE}"
    case "${PLATFORM}" in
        FreeBSD|OSX)
            ifconfig "${IFACE}" destroy ;;
        Linux)
            ip link delete "${IFACE}" ;;
        *) ;;
    esac
}

delete_bridge() {
    case "${PLATFORM}" in
        FreeBSD)
            sysctl net.link.tap.user_open=0
            for IF in $(ifconfig ${BRIDGE} | grep -oiE "member: .+ " | cut -d' ' -f2); do
                delete_iface ${IF}
            done
            delete_iface ${BRNAME} || exit 1
            kldunload if_tap        # unloading might fail due to dependencies
            kldunload if_bridge ;;
        Linux)
            for IF in $(ls /sys/class/net/${BRNAME}/brif); do
                if [ "${IF}" != "${UPLINK}" ]; then
                    delete_iface ${IF}
                fi
            done

            delete_iface ${BRNAME} || exit 1

            # restore the old uplink
            if [ -n "${UPLINK}" ]; then
                update_uplink ${UPLINK}
            fi ;;
        OSX)
            for IF in $(ifconfig ${BRIDGE} | grep -oiE "member: .+ " | cut -d' ' -f2); do
                delete_iface ${IF}
            done
            delete_iface ${BRNAME} || exit 1 ;;
        *)
            ;;
    esac
}

begin_iface() {
    if [ -z "${TUNNAME}" ]; then
        MODE="tun"
    else
        MODE="tap"
    fi
    case "${PLATFORM}" in
        FreeBSD)
            kldload if_${MODE}      # module might be already loaded => error
            sysctl net.link.${MODE}.user_open=1 ;;
        *)
            ;;
    esac
}

create_iface() {
    if [ -z "${TUNNAME}" ]; then
        NAME="${TAPNAME}"
        MODE="tap"
    else
        NAME="${TUNNAME}"
        MODE="tun"
    fi
    case "${PLATFORM}" in
        FreeBSD)
            echo "creating ${NAME}${N}" || exit 1
            ifconfig ${NAME}${N} create || exit 1
            chown ${SUDO_USER} /dev/${MODE}${N} || exit 1
            if [ -z "${TUNNAME}" ]; then
                ifconfig ${BRNAME} addm ${NAME}${N} || exit 1
            fi
            ifconfig tap${N} up || exit 1 ;;
        Linux)
            echo "creating ${NAME}${N}"
            ip tuntap add dev ${NAME}${N} mode ${MODE} user ${SUDO_USER} || exit 1
            if [ -n "${DEACTIVATE_IPV6}" ]; then
                echo 1 > /proc/sys/net/ipv6/conf/${NAME}${N}/disable_ipv6 || exit 1
            fi
            if [ -z "${TUNNAME}" ]; then
                ip link set dev ${NAME}${N} master ${BRNAME} || exit 1
            fi
            ip link set ${NAME}${N} up || exit 1 ;;
        OSX)
            chown ${SUDO_USER} /dev/${NAME}${N} || exit 1
            echo "start RIOT instance for ${NAME}${N} now and hit enter"
            read
            if [ -z "${TUNNAME}" ]; then
                ifconfig ${BRNAME} addm ${NAME}${N} || exit 1
            fi
            ifconfig ${NAME}${N} up || exit 1 ;;
        *)
            ;;
    esac
}

get_master() {
    IFACE=$1
    case "${PLATFORM}" in
        Linux)
            MASTER=$(ip link show ${IFACE} | grep -o "master \S\+" | cut -d' ' -f2)
            ;;
        FreeBSD|OSX)
            for IF in $(ifconfig | grep -oiE "^[a-z0-9_-]+"); do
                if ifconfig $IF | grep -q "member: $IFACE"; then
                    MASTER=${IF}
                    break
                fi
            done
            ;;
        *)
            ;;
    esac
    if [ -z "$MASTER" ]; then
        # IFACE is its own master
        echo "$IFACE"
    else
        echo "$MASTER"
    fi
}

list_bridge() {
    BRIDGE=$1
    IFACES=0
    echo -n "$BRIDGE:"
    case "${PLATFORM}" in
        Linux)
            for IF in $(ls /sys/class/net/${BRIDGE}/brif 2> /dev/null); do
                echo ""
                echo -n "- $IF"
                IFACES=$(( ${IFACES} + 1 ))
            done
            ;;
        FreeBSD|OSX)
            for IF in $(ifconfig ${BRIDGE} | grep -oiE "member: .+ " | cut -d' ' -f2); do
                echo ""
                echo -n "- $IF"
                IFACES=$(( ${IFACES} + 1 ))
            done
            ;;
        *)
            ;;
    esac
    if [ "${IFACES}" -eq 0 ]; then
        echo " []"
    else
        echo ""
    fi
}

while true ; do
    case "$1" in
        -6)
            DEACTIVATE_IPV6=1
            shift ;;
        -a|--address)
            # check if valid address + optional prefix length
            if echo "$2" | grep -q "^[a-f0-9:]\+\(/[0-9]\+\)\?$"; then
                BRIDGE_ADDRS="${BRIDGE_ADDRS} $2"
                shift 2
            else
                usage
                exit 2
            fi ;;
        -b|--bridge)
            case "$2" in
                "")
                    usage
                    exit 2 ;;
                *)
                    BRNAME="$2"
                    shift 2 ;;
            esac ;;
        -c|--create)
            if [ -n "${COMMAND}" ]; then
                usage
                exit 2
            fi
            COMMAND="create"
            case "$2" in
                "")
                    shift ;;
                *[!0-9]*)
                    usage
                    exit 2;;
                *)
                    COUNT="$2"
                    shift 2 ;;
            esac ;;
        -d|--delete)
            if [ -n "${COMMAND}" ]; then
                usage
                exit 2
            fi
            COMMAND="delete"
            shift ;;
        -f|--forwarding)
            ENABLE_FORWARDING=1
            shift ;;
        -l|--list)
            if [ -n "${COMMAND}" ]; then
                usage
                exit 2
            fi
            COMMAND="list"
            case "$2" in
                "")
                    usage
                    exit 2 ;;
                *)
                    BRNAME="$2"
                    shift 2 ;;
            esac ;;
        -h|--help)
            usage
            exit ;;
        -r|--route)
            # check if valid address + optional prefix length
            if ! echo "$2" | grep -q "^[a-f0-9:]\+\(/[0-9]\+\)\?$"; then
                usage
                exit 2
            fi
            # check if valid next hop
            if ! echo "$3" | grep -q "^[a-f0-9:]\+$"; then
                usage
                exit 2
            fi
            BRIDGE_ROUTES="${BRIDGE_ROUTES} $2-$3"
            shift 3 ;;
        -u|--uplink)
            case "$2" in
                "")
                    usage
                    exit 2 ;;
                *)
                    UPLINK="$2"
                    shift 2 ;;
            esac ;;
        -t|--tap)
            case "$2" in
                "")
                    usage
                    exit 2 ;;
                *)
                    TAPNAME="$2"
                    shift 2 ;;
            esac ;;
        --tun)
            case "$2" in
                "")
                    TUNNAME="tun"
                    shift 1 ;;
                *)
                    TUNNAME="$2"
                    shift 2 ;;
            esac ;;
        "")
            break ;;
        *)  usage
            exit 2 ;;
    esac
done

if [ -z "${COMMAND}" ]; then
    COMMAND="create"
fi
if [ -z "${SUDO_USER}" ] && [ "${COMMAND}" != "list" ]; then
    echo 'Environment variable $SUDO_USER required; Please run with `sudo`'
    exit 1
fi
case "$(uname -s)" in
    Darwin)
        PLATFORM="OSX"
        if echo "$BRNAME" | grep -v -q "^bridge"; then
            BRNAME=bridge42
        fi
        if [ -n "${TUNNAME}" ]; then
            TUNNAME="tun"
        fi
        ;;
    FreeBSD)
        PLATFORM="FreeBSD"
        if echo "$BRNAME" | grep -v -q "^bridge"; then
            BRNAME=bridge0
        fi
        if [ -n "${TUNNAME}" ]; then
            TUNNAME="tun"
        fi
        ;;
    Linux)
        PLATFORM="Linux" ;;
    *)
        unsupported_platform
        exit 1 ;;
esac

if [ -n "${TUNNAME}" ]; then
    echo "Only creating TUN interface ${TUNNAME}0 but no bridge"
    COUNT=1
    BRNAME="${TUNNAME}0"
fi

if [ "${COMMAND}" = 'create' ]; then
    if [ -z "${TUNNAME}" ]; then
        create_bridge || exit 1
    fi

    begin_iface || exit 1

    for N in $(seq 0 "$((COUNT - 1))"); do
        create_iface || exit 1
    done

    activate_forwarding || exit 1
    if [ -z "${TUNNAME}" ]; then
        up_bridge || exit 1
    fi
    add_ipv6_addrs || exit 1
    add_ipv6_routes || exit 1

elif [ "${COMMAND}" = 'delete' ]; then
    del_ipv6_routes || exit 1
    del_ipv6_addrs || exit 1
    deactivate_forwarding || exit 1
    if [ -z "${TUNNAME}" ]; then
        delete_bridge
    else
        for N in $(seq 0 "$((COUNT - 1))"); do
            delete_iface "${TUNNAME}${N}"
        done
    fi
elif [ "${COMMAND}" = 'list' ]; then
    list_bridge $(get_master "$BRNAME")
else
    echo 'unknown command'
    exit 1
fi

exit 0