96 lines
2.2 KiB
Go
96 lines
2.2 KiB
Go
package backend
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import (
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"errors"
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"fmt"
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"github.com/pboehm/ddns/shared"
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"strings"
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"time"
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)
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type Request struct {
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QType string
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QName string
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Remote string
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Local string
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RealRemote string
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ZoneId string
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}
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type Response struct {
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QType string `json:"qtype"`
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QName string `json:"qname"`
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Content string `json:"content"`
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TTL int `json:"ttl"`
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}
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type HostLookup struct {
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config *shared.Config
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hosts shared.HostBackend
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}
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func NewHostLookup(config *shared.Config, hostsBackend shared.HostBackend) *HostLookup {
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return &HostLookup{config, hostsBackend}
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}
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func (l *HostLookup) Lookup(request *Request) (*Response, error) {
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responseRecord := request.QType
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responseContent := ""
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switch request.QType {
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case "SOA":
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responseContent = fmt.Sprintf("%s. hostmaster%s. %d 1800 3600 7200 5",
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l.config.SOAFqdn, l.config.Domain, l.currentSOASerial())
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case "NS":
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responseContent = l.config.SOAFqdn
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case "A", "AAAA", "ANY":
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hostname, err := l.extractHostname(request.QName)
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if err != nil {
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return nil, err
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}
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var host *shared.Host
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if host, err = l.hosts.GetHost(hostname); err != nil {
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return nil, err
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}
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responseContent = host.Ip
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responseRecord = "A"
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if !host.IsIPv4() {
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responseRecord = "AAAA"
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}
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if (request.QType == "A" || request.QType == "AAAA") && request.QType != responseRecord {
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return nil, errors.New("IP address is not valid for requested record")
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}
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default:
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return nil, errors.New("Invalid request")
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}
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return &Response{QType: responseRecord, QName: request.QName, Content: responseContent, TTL: 5}, nil
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}
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// extractHostname extract the host part of the fqdn: pi.d.example.org -> pi
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func (l *HostLookup) extractHostname(rawQueryName string) (string, error) {
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queryName := strings.ToLower(rawQueryName)
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hostname := ""
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if strings.HasSuffix(queryName, l.config.Domain) {
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hostname = queryName[:len(queryName)-len(l.config.Domain)]
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}
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if hostname == "" {
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return "", errors.New("Query name does not correspond to our domain")
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}
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return hostname, nil
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}
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// currentSOASerial get the current SOA serial by returning the current time in seconds
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func (l *HostLookup) currentSOASerial() int64 {
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return time.Now().Unix()
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}
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