126 lines
3.5 KiB
Go
126 lines
3.5 KiB
Go
package nameserver
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import (
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"bytes"
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"fmt"
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"net"
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)
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// A zone record
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// Note: we will try to keep all the zone records information is concentrated here. Maybe not all queries will
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// use things like priorities or weights, but we do not want to create a hierarchy for dealing with all
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// possible queries...
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type ZoneRecord interface {
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Name() string // The name for this IP
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IP() net.IP // The IP (v4) address
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Priority() int // The priority
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Weight() int // The weight
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TTL() int // TTL
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}
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type ZoneLookup interface {
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// Lookup for a name
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LookupName(name string) ([]ZoneRecord, error)
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// Lookup for an address
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LookupInaddr(inaddr string) ([]ZoneRecord, error)
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}
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type ZoneObserver interface {
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// Observe anything that affects a particular name in the zone
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ObserveName(name string, observer ZoneRecordObserver) error
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// Observe anything that affects a particular IP in the zone
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ObserveInaddr(inaddr string, observer ZoneRecordObserver) error
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}
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type ZoneRecordObserver func()
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/////////////////////////////////////////////////////////////
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// A basic record struct (satisfying the ZoneRecord interface)
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type Record struct {
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name string
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ip net.IP
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priority int
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weight int
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ttl int
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}
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func (r Record) Name() string { return r.name }
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func (r Record) IP() net.IP { return r.ip }
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func (r Record) Priority() int { return r.priority }
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func (r Record) Weight() int { return r.weight }
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func (r Record) TTL() int { return r.ttl }
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func (r Record) String() string {
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var buf bytes.Buffer
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if len(r.Name()) > 0 {
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fmt.Fprintf(&buf, "%s", r.Name())
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}
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if !r.IP().IsUnspecified() {
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fmt.Fprintf(&buf, "[%s]", r.IP())
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}
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if r.Priority() > 0 {
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fmt.Fprintf(&buf, "/P:%d", r.Priority())
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}
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if r.Weight() > 0 {
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fmt.Fprintf(&buf, "/W:%d", r.Weight())
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}
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if r.TTL() > 0 {
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fmt.Fprintf(&buf, "/TTL:%d", r.TTL())
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}
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return buf.String()
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}
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/////////////////////////////////////////////////////////////
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func newParseError(reason string, addr string) *net.ParseError {
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return &net.ParseError{Type: reason, Text: addr}
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}
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// simple IPv4 type that can be used as a key in a map (in contrast with net.IP), used for sets of IPs, etc...
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type IPv4 [4]byte
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func (ip IPv4) toNetIP() net.IP { return net.IPv4(ip[0], ip[1], ip[2], ip[3]) }
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func (ip IPv4) String() string { return ip.toNetIP().String() }
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func ipToIPv4(nip net.IP) IPv4 { ip := nip.To4(); return IPv4([4]byte{ip[0], ip[1], ip[2], ip[3]}) }
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// Parse an address (eg, "10.13.12.11") and return the corresponding IPv4 (eg, "10.13.12.11")
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func addrToIPv4(addr string) (IPv4, error) {
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ip := net.ParseIP(addr)
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if ip == nil {
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return IPv4{}, newParseError("IP address", addr)
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}
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return ipToIPv4(ip), nil
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}
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// Parse a reverse address (eg, "11.12.13.10.in-addr.arpa.") and return the corresponding IPv4 (eg, "10.13.12.11")
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func raddrToIPv4(addr string) (IPv4, error) {
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l := len(addr)
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if l < rdnsDomainLen+1 {
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return IPv4{}, newParseError("too short reverse IP address", addr)
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}
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suffixLen := l - rdnsDomainLen
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suffix := addr[suffixLen+1:]
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if suffix != RDNSDomain {
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return IPv4{}, newParseError("suffix of reverse IP address", addr)
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}
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ipStr := addr[:suffixLen]
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revIP := net.ParseIP(ipStr)
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if revIP == nil {
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return IPv4{}, newParseError("reverse IP address", addr)
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}
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revIP4 := revIP.To4()
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return IPv4([4]byte{revIP4[3], revIP4[2], revIP4[1], revIP4[0]}), nil
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}
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func raddrToIP(addr string) (net.IP, error) {
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r, err := raddrToIPv4(addr)
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if err != nil {
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return net.IP{}, err
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}
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return r.toNetIP(), nil
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}
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