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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 dns
import (
"errors"
"net"
"github.com/coredhcp/coredhcp/handler"
"github.com/coredhcp/coredhcp/logger"
"github.com/coredhcp/coredhcp/plugins"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/insomniacslk/dhcp/dhcpv6"
)
var log = logger.GetLogger("plugins/dns")
// Plugin wraps the DNS plugin information.
var Plugin = plugins.Plugin{
Name: "dns",
Setup6: setup6,
Setup4: setup4,
}
var (
dnsServers6 []net.IP
dnsServers4 []net.IP
)
func setup6(args ...string) (handler.Handler6, error) {
if len(args) < 1 {
return nil, errors.New("need at least one DNS server")
}
for _, arg := range args {
server := net.ParseIP(arg)
if server.To16() == nil {
return Handler6, errors.New("expected an DNS server address, got: " + arg)
}
dnsServers6 = append(dnsServers6, server)
}
log.Infof("loaded %d DNS servers.", len(dnsServers6))
return Handler6, nil
}
func setup4(args ...string) (handler.Handler4, error) {
log.Printf("loaded plugin for DHCPv4.")
if len(args) < 1 {
return nil, errors.New("need at least one DNS server")
}
for _, arg := range args {
DNSServer := net.ParseIP(arg)
if DNSServer.To4() == nil {
return Handler4, errors.New("expected an DNS server address, got: " + arg)
}
dnsServers4 = append(dnsServers4, DNSServer)
}
log.Infof("loaded %d DNS servers.", len(dnsServers4))
return Handler4, nil
}
// Handler6 handles DHCPv6 packets for the dns plugin
func Handler6(req, resp dhcpv6.DHCPv6) (dhcpv6.DHCPv6, bool) {
decap, err := req.GetInnerMessage()
if err != nil {
log.Errorf("Could not decapsulate relayed message, aborting: %v", err)
return nil, true
}
if decap.IsOptionRequested(dhcpv6.OptionDNSRecursiveNameServer) {
resp.UpdateOption(dhcpv6.OptDNS(dnsServers6...))
}
return resp, false
}
//Handler4 handles DHCPv4 packets for the dns plugin
func Handler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
if req.IsOptionRequested(dhcpv4.OptionDomainNameServer) {
resp.Options.Update(dhcpv4.OptDNS(dnsServers4...))
}
return resp, false
}
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