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118 lines
3.1 KiB
Go
118 lines
3.1 KiB
Go
package kubernetes
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import (
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"github.com/coredns/coredns/middleware/pkg/dnsutil"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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type recordRequest struct {
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// The named port from the kubernetes DNS spec, this is the service part (think _https) from a well formed
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// SRV record.
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port string
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// The protocol is usually _udp or _tcp (if set), and comes from the protocol part of a well formed
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// SRV record.
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protocol string
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endpoint string
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service string
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namespace string
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// A each name can be for a pod or a service, here we track what we've seen. This value is true for
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// pods and false for services. If we ever need to extend this well use a typed value.
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podOrSvc string
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zone string
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federation string
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}
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// parseRequest parses the qname to find all the elements we need for querying k8s.
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func (k *Kubernetes) parseRequest(state request.Request) (r recordRequest, err error) {
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// 3 Possible cases
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// SRV Request: _port._protocol.service.namespace.[federation.]type.zone
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// A Request (endpoint): endpoint.service.namespace.[federation.]type.zone
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// A Request (service): service.namespace.[federation.]type.zone
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base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
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segs := dns.SplitDomainName(base)
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r.zone = state.Zone
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r.federation, segs = k.stripFederation(segs)
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if state.QType() == dns.TypeNS {
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return r, nil
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}
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if state.QType() == dns.TypeA && isDefaultNS(state.Name(), r) {
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return r, nil
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}
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offset := 0
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if state.QType() == dns.TypeSRV {
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// The kubernetes peer-finder expects queries with empty port and service to resolve
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// If neither is specified, treat it as a wildcard
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if len(segs) == 3 {
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r.port = "*"
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r.service = "*"
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offset = 0
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} else {
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if len(segs) != 5 {
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return r, errInvalidRequest
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}
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// This is a SRV style request, get first two elements as port and
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// protocol, stripping leading underscores if present.
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if segs[0][0] == '_' {
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r.port = segs[0][1:]
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} else {
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r.port = segs[0]
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if !wildcard(r.port) {
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return r, errInvalidRequest
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}
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}
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if segs[1][0] == '_' {
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r.protocol = segs[1][1:]
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if r.protocol != "tcp" && r.protocol != "udp" {
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return r, errInvalidRequest
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}
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} else {
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r.protocol = segs[1]
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if !wildcard(r.protocol) {
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return r, errInvalidRequest
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}
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}
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if r.port == "" || r.protocol == "" {
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return r, errInvalidRequest
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}
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offset = 2
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}
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}
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if (state.QType() == dns.TypeA || state.QType() == dns.TypeAAAA) && len(segs) == 4 {
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// This is an endpoint A/AAAA record request. Get first element as endpoint.
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r.endpoint = segs[0]
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offset = 1
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}
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if len(segs) == (offset + 3) {
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r.service = segs[offset]
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r.namespace = segs[offset+1]
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r.podOrSvc = segs[offset+2]
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return r, nil
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}
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return r, errInvalidRequest
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}
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// String return a string representation of r, it just returns all
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// fields concatenated with dots.
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// This is mostly used in tests.
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func (r recordRequest) String() string {
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s := r.port
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s += "." + r.protocol
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s += "." + r.endpoint
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s += "." + r.service
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s += "." + r.namespace
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s += "." + r.podOrSvc
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s += "." + r.zone
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s += "." + r.federation
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return s
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}
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