17d807f05f
* plugin/metadata: add metadata plugin * plugin/metadata: Add MD struct, refactor code, fix doc * plugin/metadata: simplify metadata key * plugin/metadata: improve setup_test * Support of metadata by rewrite plugin. Move calculated variables to metadata. * Move variables from metadata to pkg, add UTs, READMEs change, metadata small fixes * Add client port validation to variables_test * plugin/metadata: improve README * plugin/metadata: rename methods * plugin/metadata: Update Metadataer interface, update doc, cosmetic code changes * plugin/metadata: move colllisions check to OnStartup(). Fix default variables metadataer. * plugin/metadata: Fix comment for method setValue * plugin/metadata: change variables order to fix linter warning * plugin/metadata: rename Metadataer to Provider
109 lines
2.5 KiB
Go
109 lines
2.5 KiB
Go
package variables
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import (
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"encoding/binary"
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"fmt"
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"net"
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"strconv"
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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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const (
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queryName = "qname"
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queryType = "qtype"
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clientIP = "client_ip"
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clientPort = "client_port"
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protocol = "protocol"
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serverIP = "server_ip"
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serverPort = "server_port"
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)
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// All is a list of available variables provided by GetMetadataValue
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var All = []string{queryName, queryType, clientIP, clientPort, protocol, serverIP, serverPort}
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// GetValue calculates and returns the data specified by the variable name.
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// Supported varNames are listed in allProvidedVars.
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func GetValue(varName string, w dns.ResponseWriter, r *dns.Msg) ([]byte, error) {
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req := request.Request{W: w, Req: r}
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switch varName {
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case queryName:
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//Query name is written as ascii string
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return []byte(req.QName()), nil
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case queryType:
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return uint16ToWire(req.QType()), nil
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case clientIP:
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return ipToWire(req.Family(), req.IP())
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case clientPort:
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return portToWire(req.Port())
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case protocol:
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// Proto is written as ascii string
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return []byte(req.Proto()), nil
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case serverIP:
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ip, _, err := net.SplitHostPort(w.LocalAddr().String())
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if err != nil {
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ip = w.RemoteAddr().String()
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}
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return ipToWire(family(w.RemoteAddr()), ip)
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case serverPort:
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_, port, err := net.SplitHostPort(w.LocalAddr().String())
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if err != nil {
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port = "0"
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}
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return portToWire(port)
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}
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return nil, fmt.Errorf("unable to extract data for variable %s", varName)
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}
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// uint16ToWire writes unit16 to wire/binary format
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func uint16ToWire(data uint16) []byte {
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buf := make([]byte, 2)
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binary.BigEndian.PutUint16(buf, uint16(data))
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return buf
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}
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// ipToWire writes IP address to wire/binary format, 4 or 16 bytes depends on IPV4 or IPV6.
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func ipToWire(family int, ipAddr string) ([]byte, error) {
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switch family {
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case 1:
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return net.ParseIP(ipAddr).To4(), nil
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case 2:
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return net.ParseIP(ipAddr).To16(), nil
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}
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return nil, fmt.Errorf("invalid IP address family (i.e. version) %d", family)
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}
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// portToWire writes port to wire/binary format, 2 bytes
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func portToWire(portStr string) ([]byte, error) {
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port, err := strconv.ParseUint(portStr, 10, 16)
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if err != nil {
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return nil, err
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}
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return uint16ToWire(uint16(port)), nil
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}
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// Family returns the family of the transport, 1 for IPv4 and 2 for IPv6.
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func family(ip net.Addr) int {
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var a net.IP
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if i, ok := ip.(*net.UDPAddr); ok {
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a = i.IP
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}
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if i, ok := ip.(*net.TCPAddr); ok {
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a = i.IP
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}
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if a.To4() != nil {
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return 1
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}
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return 2
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}
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