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// Copyright 2018-present the CoreDHCP Authors. All rights reserved
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.
package mtu
import (
"errors"
"fmt"
"strconv"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/coredhcp/coredhcp/handler"
"github.com/coredhcp/coredhcp/logger"
"github.com/coredhcp/coredhcp/plugins"
)
var log = logger.GetLogger("plugins/mtu")
// Plugin wraps the MTU plugin information.
var Plugin = plugins.Plugin{
Name: "mtu",
Setup4: setup4,
// No Setup6 since DHCPv6 does not have MTU-related options
}
var (
mtu int
)
func setup4(args ...string) (handler.Handler4, error) {
if len(args) != 1 {
return nil, errors.New("need one mtu value")
}
var err error
if mtu, err = strconv.Atoi(args[0]); err != nil {
return nil, fmt.Errorf("invalid mtu: %v", args[0])
}
log.Infof("loaded mtu %d.", mtu)
return Handler4, nil
}
// Handler4 handles DHCPv4 packets for the mtu plugin
func Handler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
if req.IsOptionRequested(dhcpv4.OptionInterfaceMTU) {
resp.Options.Update(dhcpv4.Option{Code: dhcpv4.OptionInterfaceMTU, Value: dhcpv4.Uint16(mtu)})
}
return resp, false
}
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