mirror of
https://github.com/joohoi/acme-dns.git
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Refactoring DNS server part for safer paraller execution (#144)
* Refactoring DNS server part for safer paraller execution and better data structures * Fix linter issues
This commit is contained in:
Joona Hoikkala
202
dns.go
202
dns.go
@ -8,65 +8,80 @@ import (
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"time"
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)
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func readQuery(m *dns.Msg) {
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for _, que := range m.Question {
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if rr, rc, err := answer(que); err == nil {
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m.MsgHdr.Rcode = rc
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for _, r := range rr {
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m.Answer = append(m.Answer, r)
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}
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}
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}
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// Records is a slice of ResourceRecords
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type Records struct {
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Records []dns.RR
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}
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func answerTXT(q dns.Question) ([]dns.RR, int, error) {
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var ra []dns.RR
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rcode := dns.RcodeNameError
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subdomain := sanitizeDomainQuestion(q.Name)
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atxt, err := DB.GetTXTForDomain(subdomain)
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// DNSServer is the main struct for acme-dns DNS server
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type DNSServer struct {
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DB database
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Server *dns.Server
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Domains map[string]Records
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}
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// NewDNSServer parses the DNS records from config and returns a new DNSServer struct
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func NewDNSServer(db database, addr string, proto string) *DNSServer {
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var server DNSServer
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server.Server = &dns.Server{Addr: addr, Net: proto}
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server.DB = db
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server.Domains = make(map[string]Records)
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return &server
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}
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// Start starts the DNSServer
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func (d *DNSServer) Start(errorChannel chan error) {
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// DNS server part
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dns.HandleFunc(".", d.handleRequest)
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log.WithFields(log.Fields{"addr": d.Server.Addr, "proto": d.Server.Net}).Info("Listening DNS")
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err := d.Server.ListenAndServe()
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error()}).Debug("Error while trying to get record")
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return ra, dns.RcodeNameError, err
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errorChannel <- err
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}
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for _, v := range atxt {
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if len(v) > 0 {
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r := new(dns.TXT)
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r.Hdr = dns.RR_Header{Name: q.Name, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 1}
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r.Txt = append(r.Txt, v)
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ra = append(ra, r)
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rcode = dns.RcodeSuccess
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}
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}
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log.WithFields(log.Fields{"domain": q.Name}).Info("Answering TXT question for domain")
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return ra, rcode, nil
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}
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func answer(q dns.Question) ([]dns.RR, int, error) {
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if q.Qtype == dns.TypeTXT {
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return answerTXT(q)
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// ParseRecords parses a slice of DNS record string
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func (d *DNSServer) ParseRecords(config DNSConfig) {
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for _, v := range config.General.StaticRecords {
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rr, err := dns.NewRR(strings.ToLower(v))
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error(), "rr": v}).Warning("Could not parse RR from config")
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continue
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}
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// Add parsed RR
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d.appendRR(rr)
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}
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var r []dns.RR
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var rcode = dns.RcodeSuccess
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var domain = strings.ToLower(q.Name)
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var rtype = q.Qtype
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r, ok := RR.Records[rtype][domain]
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// Create serial
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serial := time.Now().Format("2006010215")
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// Add SOA
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SOAstring := fmt.Sprintf("%s. SOA %s. %s. %s 28800 7200 604800 86400", strings.ToLower(config.General.Domain), strings.ToLower(config.General.Nsname), strings.ToLower(config.General.Nsadmin), serial)
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soarr, err := dns.NewRR(SOAstring)
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error(), "soa": SOAstring}).Error("Error while adding SOA record")
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} else {
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d.appendRR(soarr)
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}
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}
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func (d *DNSServer) appendRR(rr dns.RR) {
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addDomain := rr.Header().Name
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_, ok := d.Domains[addDomain]
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if !ok {
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r, ok = RR.Records[dns.TypeCNAME][domain]
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if !ok {
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rcode = dns.RcodeNameError
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}
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d.Domains[addDomain] = Records{[]dns.RR{rr}}
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} else {
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drecs := d.Domains[addDomain]
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drecs.Records = append(drecs.Records, rr)
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d.Domains[addDomain] = drecs
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}
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log.WithFields(log.Fields{"qtype": dns.TypeToString[rtype], "domain": domain, "rcode": dns.RcodeToString[rcode]}).Debug("Answering question for domain")
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return r, rcode, nil
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log.WithFields(log.Fields{"recordtype": dns.TypeToString[rr.Header().Rrtype], "domain": addDomain}).Debug("Adding new record to domain")
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}
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func handleRequest(w dns.ResponseWriter, r *dns.Msg) {
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func (d *DNSServer) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
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m := new(dns.Msg)
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m.SetReply(r)
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if r.Opcode == dns.OpcodeQuery {
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readQuery(m)
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d.readQuery(m)
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} else if r.Opcode == dns.OpcodeUpdate {
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log.Debug("Refusing DNS Dynamic update request")
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m.MsgHdr.Rcode = dns.RcodeRefused
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@ -75,38 +90,81 @@ func handleRequest(w dns.ResponseWriter, r *dns.Msg) {
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w.WriteMsg(m)
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}
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// Parse config records
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func (r *Records) Parse(config general) {
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rrmap := make(map[uint16]map[string][]dns.RR)
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for _, v := range config.StaticRecords {
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rr, err := dns.NewRR(strings.ToLower(v))
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error(), "rr": v}).Warning("Could not parse RR from config")
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continue
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func (d *DNSServer) readQuery(m *dns.Msg) {
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for _, que := range m.Question {
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if rr, rc, err := d.answer(que); err == nil {
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m.MsgHdr.Rcode = rc
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for _, r := range rr {
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m.Answer = append(m.Answer, r)
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}
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}
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// Add parsed RR to the list
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rrmap = appendRR(rrmap, rr)
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}
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// Create serial
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serial := time.Now().Format("2006010215")
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// Add SOA
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SOAstring := fmt.Sprintf("%s. SOA %s. %s. %s 28800 7200 604800 86400", strings.ToLower(config.Domain), strings.ToLower(config.Nsname), strings.ToLower(config.Nsadmin), serial)
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soarr, err := dns.NewRR(SOAstring)
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error(), "soa": SOAstring}).Error("Error while adding SOA record")
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} else {
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rrmap = appendRR(rrmap, soarr)
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}
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r.Records = rrmap
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}
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func appendRR(rrmap map[uint16]map[string][]dns.RR, rr dns.RR) map[uint16]map[string][]dns.RR {
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_, ok := rrmap[rr.Header().Rrtype]
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func (d *DNSServer) getRecord(q dns.Question) ([]dns.RR, error) {
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var rr []dns.RR
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var cnames []dns.RR
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domain, ok := d.Domains[q.Name]
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if !ok {
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newrr := make(map[string][]dns.RR)
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rrmap[rr.Header().Rrtype] = newrr
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return rr, fmt.Errorf("No records for domain %s", q.Name)
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}
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rrmap[rr.Header().Rrtype][rr.Header().Name] = append(rrmap[rr.Header().Rrtype][rr.Header().Name], rr)
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log.WithFields(log.Fields{"recordtype": dns.TypeToString[rr.Header().Rrtype], "domain": rr.Header().Name}).Debug("Adding new record type to domain")
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return rrmap
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for _, ri := range domain.Records {
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if ri.Header().Rrtype == q.Qtype {
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rr = append(rr, ri)
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}
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if ri.Header().Rrtype == dns.TypeCNAME {
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cnames = append(cnames, ri)
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}
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}
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if len(rr) == 0 {
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return cnames, nil
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}
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return rr, nil
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}
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// answeringForDomain checks if we have any records for a domain
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func (d *DNSServer) answeringForDomain(q dns.Question) bool {
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_, ok := d.Domains[q.Name]
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return ok
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}
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func (d *DNSServer) answer(q dns.Question) ([]dns.RR, int, error) {
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var rcode int
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if !d.answeringForDomain(q) {
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rcode = dns.RcodeNameError
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}
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r, _ := d.getRecord(q)
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if q.Qtype == dns.TypeTXT {
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txtRRs, err := d.answerTXT(q)
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if err == nil {
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for _, txtRR := range txtRRs {
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r = append(r, txtRR)
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}
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}
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}
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if len(r) > 0 {
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// Make sure that we return NOERROR if there were dynamic records for the domain
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rcode = dns.RcodeSuccess
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}
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log.WithFields(log.Fields{"qtype": dns.TypeToString[q.Qtype], "domain": q.Name, "rcode": dns.RcodeToString[rcode]}).Debug("Answering question for domain")
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return r, rcode, nil
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}
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func (d *DNSServer) answerTXT(q dns.Question) ([]dns.RR, error) {
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var ra []dns.RR
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subdomain := sanitizeDomainQuestion(q.Name)
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atxt, err := d.DB.GetTXTForDomain(subdomain)
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if err != nil {
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log.WithFields(log.Fields{"error": err.Error()}).Debug("Error while trying to get record")
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return ra, err
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}
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for _, v := range atxt {
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if len(v) > 0 {
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r := new(dns.TXT)
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r.Hdr = dns.RR_Header{Name: q.Name, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 1}
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r.Txt = append(r.Txt, v)
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ra = append(ra, r)
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}
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}
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return ra, nil
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}
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