mirror of https://github.com/status-im/consul.git
v1 dns - add doc strings for functions and update function names to be consistent and more descriptive. (#20194)
v1 dns - add doc strings for functions and update function names to be consistent and mre descriptive.
This commit is contained in:
John Murret
GitHub
parent
7f9ed032fd
commit
93e06b799e
92
agent/dns.go
92
agent/dns.go
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@ -427,7 +427,7 @@ func (d *DNSServer) handlePtr(resp dns.ResponseWriter, req *dns.Msg) {
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// Only add the SOA if requested
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if req.Question[0].Qtype == dns.TypeSOA {
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d.addSOA(cfg, m, q.Name)
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d.addSOAToMessage(cfg, m, q.Name)
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}
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datacenter := d.agent.config.Datacenter
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@ -546,14 +546,14 @@ func (d *DNSServer) handleQuery(resp dns.ResponseWriter, req *dns.Msg) {
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switch req.Question[0].Qtype {
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case dns.TypeSOA:
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ns, glue := d.nameservers(req.Question[0].Name, cfg, maxRecursionLevelDefault)
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m.Answer = append(m.Answer, d.soa(cfg, q.Name))
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ns, glue := d.getNameserversAndNodeRecord(req.Question[0].Name, cfg, maxRecursionLevelDefault)
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m.Answer = append(m.Answer, d.makeSOARecord(cfg, q.Name))
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m.Ns = append(m.Ns, ns...)
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m.Extra = append(m.Extra, glue...)
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m.SetRcode(req, dns.RcodeSuccess)
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case dns.TypeNS:
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ns, glue := d.nameservers(req.Question[0].Name, cfg, maxRecursionLevelDefault)
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ns, glue := d.getNameserversAndNodeRecord(req.Question[0].Name, cfg, maxRecursionLevelDefault)
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m.Answer = ns
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m.Extra = glue
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m.SetRcode(req, dns.RcodeSuccess)
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@ -565,7 +565,7 @@ func (d *DNSServer) handleQuery(resp dns.ResponseWriter, req *dns.Msg) {
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err = d.dispatch(resp.RemoteAddr(), req, m, maxRecursionLevelDefault)
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rCode := rCodeFromError(err)
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if rCode == dns.RcodeNameError || errors.Is(err, errNoData) {
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d.addSOA(cfg, m, q.Name)
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d.addSOAToMessage(cfg, m, q.Name)
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}
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m.SetRcode(req, rCode)
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}
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@ -579,7 +579,8 @@ func (d *DNSServer) handleQuery(resp dns.ResponseWriter, req *dns.Msg) {
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}
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}
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func (d *DNSServer) soa(cfg *dnsConfig, questionName string) *dns.SOA {
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// Craft dns records for an SOA
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func (d *DNSServer) makeSOARecord(cfg *dnsConfig, questionName string) *dns.SOA {
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domain := d.domain
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if d.altDomain != "" && strings.HasSuffix(questionName, "."+d.altDomain) {
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domain = d.altDomain
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@ -604,14 +605,13 @@ func (d *DNSServer) soa(cfg *dnsConfig, questionName string) *dns.SOA {
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}
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// addSOA is used to add an SOA record to a message for the given domain
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func (d *DNSServer) addSOA(cfg *dnsConfig, msg *dns.Msg, questionName string) {
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msg.Ns = append(msg.Ns, d.soa(cfg, questionName))
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func (d *DNSServer) addSOAToMessage(cfg *dnsConfig, msg *dns.Msg, questionName string) {
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msg.Ns = append(msg.Ns, d.makeSOARecord(cfg, questionName))
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}
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// nameservers returns the names and ip addresses of up to three random servers
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// getNameserversAndNodeRecord returns the names and ip addresses of up to three random servers
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// in the current cluster which serve as authoritative name servers for zone.
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func (d *DNSServer) nameservers(questionName string, cfg *dnsConfig, maxRecursionLevel int) (ns []dns.RR, extra []dns.RR) {
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func (d *DNSServer) getNameserversAndNodeRecord(questionName string, cfg *dnsConfig, maxRecursionLevel int) (ns []dns.RR, extra []dns.RR) {
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out, err := d.lookupServiceNodes(cfg, serviceLookup{
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Datacenter: d.agent.config.Datacenter,
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Service: structs.ConsulServiceName,
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@ -666,12 +666,10 @@ func (d *DNSServer) nameservers(questionName string, cfg *dnsConfig, maxRecursio
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return
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}
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func (d *DNSServer) invalidQuery(req, resp *dns.Msg, cfg *dnsConfig, qName string) {
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d.logger.Warn("QName invalid", "qname", qName)
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d.addSOA(cfg, resp, qName)
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resp.SetRcode(req, dns.RcodeNameError)
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}
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// parseDatacenter will do the following:
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// - if zero labels are passed, return true without modifying the datacenter parameter
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// - if one label is passed, set the datacenter parameter to the label and return true
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// - Otherwise it will return false without modifying the datacenter parameter
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func (d *DNSServer) parseDatacenter(labels []string, datacenter *string) bool {
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switch len(labels) {
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case 1:
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@ -846,7 +844,7 @@ func (d *DNSServer) dispatch(remoteAddr net.Addr, req, resp *dns.Msg, maxRecursi
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// tag[.tag].name.service.consul
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}
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err = d.serviceLookup(cfg, lookup, req, resp)
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err = d.handleServiceQuery(cfg, lookup, req, resp)
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// Return if we are error free right away, otherwise loop again if we can
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if err == nil {
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return nil
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@ -877,7 +875,7 @@ func (d *DNSServer) dispatch(remoteAddr net.Addr, req, resp *dns.Msg, maxRecursi
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EnterpriseMeta: locality.EnterpriseMeta,
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}
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// name.connect.consul
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return d.serviceLookup(cfg, lookup, req, resp)
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return d.handleServiceQuery(cfg, lookup, req, resp)
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case "virtual":
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if len(queryParts) < 1 {
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@ -944,7 +942,7 @@ func (d *DNSServer) dispatch(remoteAddr net.Addr, req, resp *dns.Msg, maxRecursi
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EnterpriseMeta: locality.EnterpriseMeta,
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}
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// name.ingress.consul
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return d.serviceLookup(cfg, lookup, req, resp)
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return d.handleServiceQuery(cfg, lookup, req, resp)
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case "node":
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if len(queryParts) < 1 {
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@ -977,7 +975,7 @@ func (d *DNSServer) dispatch(remoteAddr net.Addr, req, resp *dns.Msg, maxRecursi
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lookup.Datacenter = ""
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}
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return d.nodeLookup(cfg, lookup, req, resp)
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return d.handleNodeQuery(cfg, lookup, req, resp)
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case "query":
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n := len(queryParts)
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@ -1009,7 +1007,7 @@ func (d *DNSServer) dispatch(remoteAddr net.Addr, req, resp *dns.Msg, maxRecursi
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query = strings.Join(queryParts, ".")
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}
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err := d.preparedQueryLookup(cfg, datacenter, query, remoteAddr, req, resp, maxRecursionLevel)
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err := d.handlePreparedQuery(cfg, datacenter, query, remoteAddr, req, resp, maxRecursionLevel)
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return ecsNotGlobalError{error: err}
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case "addr":
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@ -1101,8 +1099,8 @@ func rCodeFromError(err error) int {
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}
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}
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// nodeLookup is used to handle a node query
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func (d *DNSServer) nodeLookup(cfg *dnsConfig, lookup nodeLookup, req, resp *dns.Msg) error {
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// handleNodeQuery is used to handle a node query
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func (d *DNSServer) handleNodeQuery(cfg *dnsConfig, lookup nodeLookup, req, resp *dns.Msg) error {
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// Only handle ANY, A, AAAA, and TXT type requests
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qType := req.Question[0].Qtype
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if qType != dns.TypeANY && qType != dns.TypeA && qType != dns.TypeAAAA && qType != dns.TypeTXT {
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@ -1146,12 +1144,14 @@ func (d *DNSServer) nodeLookup(cfg *dnsConfig, lookup nodeLookup, req, resp *dns
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}
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if cfg.NodeMetaTXT || qType == dns.TypeTXT || qType == dns.TypeANY {
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metas := d.generateMeta(q.Name, n, cfg.NodeTTL)
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metas := d.makeTXTRecordFromNodeMeta(q.Name, n, cfg.NodeTTL)
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*metaTarget = append(*metaTarget, metas...)
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}
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return nil
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}
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// lookupNode is used to look up a node in the Consul catalog within NodeServices.
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// If the config is set to UseCache, it will get the record from the agent cache.
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func (d *DNSServer) lookupNode(cfg *dnsConfig, args *structs.NodeSpecificRequest) (*structs.IndexedNodeServices, error) {
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var out structs.IndexedNodeServices
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@ -1432,7 +1432,8 @@ func (d *DNSServer) trimDNSResponse(cfg *dnsConfig, network string, req, resp *d
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}
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}
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// lookupServiceNodes returns nodes with a given service.
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// lookupServiceNodes is used to look up a node in the Consul health catalog within ServiceNodes.
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// If the config is set to UseCache, it will get the record from the agent cache.
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func (d *DNSServer) lookupServiceNodes(cfg *dnsConfig, lookup serviceLookup) (structs.IndexedCheckServiceNodes, error) {
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serviceTags := []string{}
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if lookup.Tag != "" {
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@ -1469,8 +1470,8 @@ func (d *DNSServer) lookupServiceNodes(cfg *dnsConfig, lookup serviceLookup) (st
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return out, nil
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}
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// serviceLookup is used to handle a service query
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func (d *DNSServer) serviceLookup(cfg *dnsConfig, lookup serviceLookup, req, resp *dns.Msg) error {
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// handleServiceQuery is used to handle a service query
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func (d *DNSServer) handleServiceQuery(cfg *dnsConfig, lookup serviceLookup, req, resp *dns.Msg) error {
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out, err := d.lookupServiceNodes(cfg, lookup)
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if err != nil {
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return fmt.Errorf("rpc request failed: %w", err)
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@ -1490,9 +1491,9 @@ func (d *DNSServer) serviceLookup(cfg *dnsConfig, lookup serviceLookup, req, res
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// Add various responses depending on the request
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qType := req.Question[0].Qtype
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if qType == dns.TypeSRV {
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d.serviceSRVRecords(cfg, lookup, out.Nodes, req, resp, ttl, lookup.MaxRecursionLevel)
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d.addServiceSRVRecordsToMessage(cfg, lookup, out.Nodes, req, resp, ttl, lookup.MaxRecursionLevel)
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} else {
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d.serviceNodeRecords(cfg, lookup, out.Nodes, req, resp, ttl, lookup.MaxRecursionLevel)
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d.addServiceNodeRecordsToMessage(cfg, lookup, out.Nodes, req, resp, ttl, lookup.MaxRecursionLevel)
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}
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if len(resp.Answer) == 0 {
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@ -1518,8 +1519,8 @@ func ednsSubnetForRequest(req *dns.Msg) *dns.EDNS0_SUBNET {
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return nil
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}
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// preparedQueryLookup is used to handle a prepared query.
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func (d *DNSServer) preparedQueryLookup(cfg *dnsConfig, datacenter, query string, remoteAddr net.Addr, req, resp *dns.Msg, maxRecursionLevel int) error {
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// handlePreparedQuery is used to handle a prepared query.
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func (d *DNSServer) handlePreparedQuery(cfg *dnsConfig, datacenter, query string, remoteAddr net.Addr, req, resp *dns.Msg, maxRecursionLevel int) error {
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// Execute the prepared query.
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args := structs.PreparedQueryExecuteRequest{
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Datacenter: datacenter,
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@ -1600,9 +1601,9 @@ func (d *DNSServer) preparedQueryLookup(cfg *dnsConfig, datacenter, query string
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// because peering is not supported with prepared queries.
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lookup := serviceLookup{Datacenter: out.Datacenter}
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if qType == dns.TypeSRV {
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d.serviceSRVRecords(cfg, lookup, out.Nodes, req, resp, ttl, maxRecursionLevel)
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d.addServiceSRVRecordsToMessage(cfg, lookup, out.Nodes, req, resp, ttl, maxRecursionLevel)
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} else {
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d.serviceNodeRecords(cfg, lookup, out.Nodes, req, resp, ttl, maxRecursionLevel)
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d.addServiceNodeRecordsToMessage(cfg, lookup, out.Nodes, req, resp, ttl, maxRecursionLevel)
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}
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if len(resp.Answer) == 0 {
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@ -1611,6 +1612,8 @@ func (d *DNSServer) preparedQueryLookup(cfg *dnsConfig, datacenter, query string
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return nil
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}
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// lookupPreparedQuery is used to execute a PreparedQuery against the Consul catalog.
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// If the config is set to UseCache, it will use agent cache.
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func (d *DNSServer) lookupPreparedQuery(cfg *dnsConfig, args structs.PreparedQueryExecuteRequest) (*structs.PreparedQueryExecuteResponse, error) {
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var out structs.PreparedQueryExecuteResponse
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@ -1652,8 +1655,8 @@ RPC:
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return &out, nil
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}
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// serviceNodeRecords is used to add the node records for a service lookup
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func (d *DNSServer) serviceNodeRecords(cfg *dnsConfig, lookup serviceLookup, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration, maxRecursionLevel int) {
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// addServiceNodeRecordsToMessage is used to add the node records for a service lookup
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func (d *DNSServer) addServiceNodeRecordsToMessage(cfg *dnsConfig, lookup serviceLookup, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration, maxRecursionLevel int) {
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handled := make(map[string]struct{})
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var answerCNAME []dns.RR = nil
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@ -1661,7 +1664,7 @@ func (d *DNSServer) serviceNodeRecords(cfg *dnsConfig, lookup serviceLookup, nod
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for _, node := range nodes {
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// Add the node record
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had_answer := false
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records, _ := d.nodeServiceRecords(lookup, node, req, ttl, cfg, maxRecursionLevel)
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records, _ := d.makeNodeServiceRecords(lookup, node, req, ttl, cfg, maxRecursionLevel)
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if len(records) == 0 {
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continue
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}
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@ -1760,6 +1763,7 @@ func (d *DNSServer) encodeIPAsFqdn(questionName string, lookup serviceLookup, ip
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return fmt.Sprintf("%s.addr.%s.%s", ipStr, lookup.Datacenter, respDomain)
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}
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// Craft dns records for a an A record for an IP address
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func makeARecord(qType uint16, ip net.IP, ttl time.Duration) dns.RR {
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var ipRecord dns.RR
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@ -1962,7 +1966,8 @@ MORE_REC:
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return answers, nil
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}
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func (d *DNSServer) nodeServiceRecords(lookup serviceLookup, node structs.CheckServiceNode, req *dns.Msg, ttl time.Duration, cfg *dnsConfig, maxRecursionLevel int) ([]dns.RR, []dns.RR) {
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// Craft dns records from a CheckServiceNode struct
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func (d *DNSServer) makeNodeServiceRecords(lookup serviceLookup, node structs.CheckServiceNode, req *dns.Msg, ttl time.Duration, cfg *dnsConfig, maxRecursionLevel int) ([]dns.RR, []dns.RR) {
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addrTranslate := TranslateAddressAcceptDomain
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if req.Question[0].Qtype == dns.TypeA {
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addrTranslate |= TranslateAddressAcceptIPv4
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@ -2013,7 +2018,8 @@ func (d *DNSServer) nodeServiceRecords(lookup serviceLookup, node structs.CheckS
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return d.makeRecordFromFQDN(lookup, serviceAddr, node, req, ttl, cfg, maxRecursionLevel)
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}
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func (d *DNSServer) generateMeta(qName string, node *structs.Node, ttl time.Duration) []dns.RR {
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// Craft dns records for TXT from a node's metadata
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func (d *DNSServer) makeTXTRecordFromNodeMeta(qName string, node *structs.Node, ttl time.Duration) []dns.RR {
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extra := make([]dns.RR, 0, len(node.Meta))
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for key, value := range node.Meta {
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txt := value
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@ -2034,8 +2040,8 @@ func (d *DNSServer) generateMeta(qName string, node *structs.Node, ttl time.Dura
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return extra
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}
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// serviceARecords is used to add the SRV records for a service lookup
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func (d *DNSServer) serviceSRVRecords(cfg *dnsConfig, lookup serviceLookup, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration, maxRecursionLevel int) {
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// addServiceSRVRecordsToMessage is used to add the SRV records for a service lookup
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func (d *DNSServer) addServiceSRVRecordsToMessage(cfg *dnsConfig, lookup serviceLookup, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration, maxRecursionLevel int) {
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handled := make(map[string]struct{})
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for _, node := range nodes {
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@ -2052,14 +2058,14 @@ func (d *DNSServer) serviceSRVRecords(cfg *dnsConfig, lookup serviceLookup, node
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}
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handled[tuple] = struct{}{}
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answers, extra := d.nodeServiceRecords(lookup, node, req, ttl, cfg, maxRecursionLevel)
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answers, extra := d.makeNodeServiceRecords(lookup, node, req, ttl, cfg, maxRecursionLevel)
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respDomain := d.getResponseDomain(req.Question[0].Name)
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resp.Answer = append(resp.Answer, answers...)
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resp.Extra = append(resp.Extra, extra...)
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if cfg.NodeMetaTXT {
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resp.Extra = append(resp.Extra, d.generateMeta(nodeCanonicalDNSName(lookup, node.Node.Node, respDomain), node.Node, ttl)...)
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resp.Extra = append(resp.Extra, d.makeTXTRecordFromNodeMeta(nodeCanonicalDNSName(lookup, node.Node.Node, respDomain), node.Node, ttl)...)
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}
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}
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}
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