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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 autoconfigure
// This plugin implements RFC2563:
// 1. If the client has been allocated an IP address, do nothing
// 2. If the client has not been allocated an IP address
// (yiaddr=0.0.0.0), then:
// 2a. If the client has requested the "AutoConfigure" option,
// then add the defined value to the response
// 2b. Otherwise, terminate processing and send no reply
//
// This plugin should be used at the end of the plugin chain,
// after any IP address allocation has taken place.
//
// The optional argument is the string "DoNotAutoConfigure" or
// "AutoConfigure" (or "0" or "1" respectively). The default
// is DoNotAutoConfigure.
import (
"errors"
"fmt"
"github.com/coredhcp/coredhcp/handler"
"github.com/coredhcp/coredhcp/logger"
"github.com/coredhcp/coredhcp/plugins"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/sirupsen/logrus"
)
var log = logger.GetLogger("plugins/autoconfigure")
var autoconfigure dhcpv4.AutoConfiguration
var Plugin = plugins.Plugin{
Name: "autoconfigure",
Setup4: setup4,
}
var argMap = map[string]dhcpv4.AutoConfiguration{
"0": dhcpv4.AutoConfiguration(0),
"1": dhcpv4.AutoConfiguration(1),
"DoNotAutoConfigure": dhcpv4.DoNotAutoConfigure,
"AutoConfigure": dhcpv4.AutoConfigure,
}
func setup4(args ...string) (handler.Handler4, error) {
if len(args) > 0 {
var ok bool
autoconfigure, ok = argMap[args[0]]
if !ok {
return nil, fmt.Errorf("unexpected value '%v' for autoconfigure argument", args[0])
}
}
if len(args) > 1 {
return nil, errors.New("too many arguments")
}
return Handler4, nil
}
func Handler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
if resp.MessageType() != dhcpv4.MessageTypeOffer || !resp.YourIPAddr.IsUnspecified() {
return resp, false
}
ac, ok := req.AutoConfigure()
if ok {
resp.UpdateOption(dhcpv4.OptAutoConfigure(autoconfigure))
log.WithFields(logrus.Fields{
"mac": req.ClientHWAddr.String(),
"autoconfigure": fmt.Sprintf("%v", ac),
}).Debugf("Responded with autoconfigure %v", autoconfigure)
return resp, false
}
log.WithFields(logrus.Fields{
"mac": req.ClientHWAddr.String(),
"autoconfigure": "nil",
}).Debugf("Client does not support autoconfigure")
// RFC2563 2.3: if no address is chosen for the host [...]
// If the DHCPDISCOVER does not contain the Auto-Configure option,
// it is not answered.
return nil, true
}
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