consul/agent/dns/router_query.go

126 lines
4.0 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1
package dns
import (
"errors"
"strings"
"github.com/miekg/dns"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/discovery"
)
// buildQueryFromDNSMessage returns a discovery.Query from a DNS message.
func buildQueryFromDNSMessage(req *dns.Msg, domain, altDomain string, cfg *RouterDynamicConfig, defaultEntMeta acl.EnterpriseMeta) (*discovery.Query, error) {
queryType, queryParts, querySuffixes := getQueryTypePartsAndSuffixesFromDNSMessage(req, domain, altDomain)
locality, ok := ParseLocality(querySuffixes, defaultEntMeta, cfg.enterpriseDNSConfig)
if !ok {
return nil, errors.New("invalid locality")
}
// TODO(v2-dns): This needs to be deprecated.
peerName := locality.peer
if peerName == "" {
// If the peer name was not explicitly defined, fall back to the ambiguously-parsed version.
peerName = locality.peerOrDatacenter
}
return &discovery.Query{
QueryType: queryType,
QueryPayload: discovery.QueryPayload{
Name: queryParts[len(queryParts)-1],
Tenancy: discovery.QueryTenancy{
EnterpriseMeta: locality.EnterpriseMeta,
// v2-dns: revisit if we need this after the rest of this works.
// SamenessGroup: "",
// The datacenter of the request is not specified because cross-datacenter virtual IP
// queries are not supported. This guard rail is in place because virtual IPs are allocated
// within a DC, therefore their uniqueness is not guaranteed globally.
Peer: peerName,
Datacenter: locality.datacenter,
},
// TODO(v2-dns): what should these be?
//PortName: "",
//Tag: "",
//RemoteAddr: nil,
//DisableFailover: false,
},
}, nil
}
// getQueryTypePartsAndSuffixesFromDNSMessage returns the query type, the parts, and suffixes of the query name.
func getQueryTypePartsAndSuffixesFromDNSMessage(req *dns.Msg, domain, altDomain string) (queryType discovery.QueryType, parts []string, suffixes []string) {
// Get the QName without the domain suffix
qName := trimDomainFromQuestionName(req.Question[0].Name, domain, altDomain)
// Split into the label parts
labels := dns.SplitDomainName(qName)
done := false
for i := len(labels) - 1; i >= 0 && !done; i-- {
queryType = getQueryTypeFromLabels(labels[i])
switch queryType {
case discovery.QueryTypeInvalid:
// If we don't recognize the query type, we keep going until we find one we do.
case discovery.QueryTypeService,
discovery.QueryTypeConnect, discovery.QueryTypeVirtual, discovery.QueryTypeIngress,
discovery.QueryTypeNode, discovery.QueryTypePreparedQuery:
parts = labels[:i]
suffixes = labels[i+1:]
done = true
default:
// If this is a SRV query the "service" label is optional, we add it back to use the
// existing code-path.
if req.Question[0].Qtype == dns.TypeSRV && strings.HasPrefix(labels[i], "_") {
parts = labels[:i+1]
suffixes = labels[i+1:]
done = true
}
}
}
return queryType, parts, suffixes
}
// trimDomainFromQuestionName returns the question name without the domain suffix.
func trimDomainFromQuestionName(questionName, domain, altDomain string) string {
qName := strings.ToLower(dns.Fqdn(questionName))
longer := domain
shorter := altDomain
if len(shorter) > len(longer) {
longer, shorter = shorter, longer
}
if strings.HasSuffix(qName, "."+strings.TrimLeft(longer, ".")) {
return strings.TrimSuffix(qName, longer)
}
return strings.TrimSuffix(qName, shorter)
}
// getQueryTypeFromLabels returns the query type from the labels.
func getQueryTypeFromLabels(label string) discovery.QueryType {
switch label {
case "service":
return discovery.QueryTypeService
case "connect":
return discovery.QueryTypeConnect
case "virtual":
return discovery.QueryTypeVirtual
case "ingress":
return discovery.QueryTypeIngress
case "node":
return discovery.QueryTypeNode
case "query":
return discovery.QueryTypePreparedQuery
case "workload":
return discovery.QueryTypeWorkload
default:
return discovery.QueryTypeInvalid
}
}