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https://github.com/netbirdio/netbird.git
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a78fd69f80
Added host configurators for Linux, Windows, and macOS. The host configurator will update the peer system configuration directing DNS queries according to its capabilities. Some Linux distributions don't support split (match) DNS or custom ports, and that will be reported to our management system in another PR
110 lines
2.9 KiB
Go
110 lines
2.9 KiB
Go
// Package dns implement dns types and standard methods and functions
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// to parse and normalize dns records and configuration
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package dns
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import (
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"fmt"
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"github.com/miekg/dns"
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"golang.org/x/net/idna"
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"net"
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"regexp"
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"strings"
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)
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const (
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// DefaultDNSPort well-known port number
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DefaultDNSPort = 53
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// RootZone is a string representation of the root zone
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RootZone = "."
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// DefaultClass is the class supported by the system
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DefaultClass = "IN"
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)
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const invalidHostLabel = "[^a-zA-Z0-9-]+"
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// Config represents a dns configuration that is exchanged between management and peers
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type Config struct {
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// ServiceEnable indicates if the service should be enabled
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ServiceEnable bool
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// NameServerGroups contains a list of nameserver group
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NameServerGroups []*NameServerGroup
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// CustomZones contains a list of custom zone
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CustomZones []CustomZone
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}
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// CustomZone represents a custom zone to be resolved by the dns server
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type CustomZone struct {
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// Domain is the zone's domain
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Domain string
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// Records custom zone records
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Records []SimpleRecord
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}
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// SimpleRecord provides a simple DNS record specification for CNAME, A and AAAA records
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type SimpleRecord struct {
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// Name domain name
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Name string
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// Type of record, 1 for A, 5 for CNAME, 28 for AAAA. see https://pkg.go.dev/github.com/miekg/dns@v1.1.41#pkg-constants
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Type int
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// Class dns class, currently use the DefaultClass for all records
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Class string
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// TTL time-to-live for the record
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TTL int
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// RData is the actual value resolved in a dns query
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RData string
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}
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// String returns a string of the simple record formatted as:
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// <Name> <TTL> <Class> <Type> <RDATA>
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func (s SimpleRecord) String() string {
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fqdn := dns.Fqdn(s.Name)
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return fmt.Sprintf("%s %d %s %s %s", fqdn, s.TTL, s.Class, dns.Type(s.Type).String(), s.RData)
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}
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// Len returns the length of the RData field, based on its type
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func (s SimpleRecord) Len() uint16 {
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emptyString := s.RData == ""
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switch s.Type {
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case 1:
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if emptyString {
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return 0
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}
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return net.IPv4len
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case 5:
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if emptyString || s.RData == "." {
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return 1
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}
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return uint16(len(s.RData) + 1)
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case 28:
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if emptyString {
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return 0
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}
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return net.IPv6len
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default:
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return 0
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}
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}
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// GetParsedDomainLabel returns a domain label with max 59 characters,
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// parsed for old Hosts.txt requirements, and converted to ASCII and lowercase
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func GetParsedDomainLabel(name string) (string, error) {
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labels := dns.SplitDomainName(name)
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if len(labels) == 0 {
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return "", fmt.Errorf("got empty label list for name \"%s\"", name)
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}
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rawLabel := labels[0]
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ascii, err := idna.Punycode.ToASCII(rawLabel)
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if err != nil {
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return "", fmt.Errorf("unable to convert host lavel to ASCII, error: %v", err)
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}
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invalidHostMatcher := regexp.MustCompile(invalidHostLabel)
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validHost := strings.ToLower(invalidHostMatcher.ReplaceAllString(ascii, "-"))
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if len(validHost) > 58 {
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validHost = validHost[:59]
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}
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return validHost, nil
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}
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