# -*-Shell-script-*-

# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the MIT License. See the LICENSE accompanying this file
# for the specific language governing permissions and limitations under
# the License.

# Library of function shared across various components of
# ec2-net-utils.  Ideally the functions here would have been added
# directly to ec2net-functions, and it would have been imported into
# programs that need it.  However, that file is large, and makes a
# number of modifications to the global process namespace.  We want to
# make these functions usable in environments like dhclient hooks,
# which all run within a single shell process, and modifying the
# global namespace so extensively is unsafe.  So we introduce this
# file and move definitions into it that are less likely to conflict
# with third-party hooks or other such modifications.

# Normally the ec2-net-utils scripts assume ownership of the ifcfg-* configuration files.
should_sync_interface() {
    local interface=$1
    local config_file=$2
    if [ -z "$interface" ] ||
           [ -z "$config_file" ]; then
        return 1
    fi
    local unmanaged
    if [ -s ${config_file} ]; then
        # make no changes to unmanaged interfaces
        unmanaged=$(LANG=C grep -l "^[[:space:]]*EC2SYNC=no\([[:space:]#]\|$\)" $config_file)
        if [ "${config_file}" == "${unmanaged}" ]; then
            logger --tag ec2net "${interface} should not be unmanaged"
            return 1
        fi
    fi
    return 0
}

# VPC assign IPv4 addresses in the 169.254/16 link-local range in
# IPv6-only subnets.
subnet_supports_ipv4() {
    local address=$1
    case "$address" in
        "")
            return 1
            ;;
        169.254.*)
            return 1
            ;;
        *)
            return 0
            ;;
    esac
}

get_interface_rt_table() {
    local interface=$1
    # generate a routing table number
    local RTABLE=${interface#eth}
    let RTABLE+=10000
    echo "$RTABLE"
    return 0
}

# Whether or not a default route for the given interface should be
# added to the main route table in addition to the interface's private
# route table.
should_use_mainroutetable() {
    local config_file="$1"
    if [ -s "$config_file" ]; then
        local no_default_route
        no_default_route=$(LANG=C grep -l "^[[:space:]]*MAINROUTETABLE=no\([[:space:]#]\|$\)" $config_file)
        if [ "${no_default_route}" == "${config_file}" ]; then
            return 1
        fi
    fi
    return 0
}

# Whether or not all IPs in a delegated prefix should be directly provisioned.
# Defaults to no for backwards-compatability.
# Note: Currently only supported for IPv4.
should_provision_prefix_ips() {
    local config_file="$1"
    if [ -s "$config_file" ]; then
        local provision_prefix_ips
        provision_prefix_ips=$(LANG=C grep -l "^[[:space:]]*EC2PROVISIONPFXIPS=yes\([[:space:]#]\|$\)" $config_file)
        if [ "${provision_prefix_ips}" == "${config_file}" ]; then
            logger --tag ec2net "${interface} prefix ips should be provisioned"
            return 0
        fi
    fi
    return 1
}

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