116 lines
2.5 KiB
Go
116 lines
2.5 KiB
Go
package weavedns
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import (
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"github.com/miekg/dns"
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"net"
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"sync"
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)
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type Zone interface {
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AddRecord(ident string, name string, localIP net.IP, weaveIP net.IP) error
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DeleteRecord(ident string, weaveIp net.IP) error
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DeleteRecordsFor(ident string) error
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MatchLocal(name string) (net.IP, error)
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MatchLocalIP(ip net.IP) (string, error)
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}
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type Record struct {
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Ident string
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Name string
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LocalIP net.IP
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WeaveIP net.IP
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}
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// Very simple data structure for now, with linear searching.
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// TODO: make more sophisticated to improve performance.
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type ZoneDb struct {
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mx sync.RWMutex
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recs []Record
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}
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type LookupError string
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func (ops LookupError) Error() string {
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return "Unable to find " + string(ops)
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}
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type DuplicateError struct {
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Name string
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WeaveIP net.IP
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Ident string
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}
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func (err DuplicateError) Error() string {
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return "Duplicate " + err.Name + "," + err.WeaveIP.String() + " for identity " + err.Ident
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}
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func (zone *ZoneDb) indexOf(match func(Record) bool) int {
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for i, r := range zone.recs {
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if match(r) {
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return i
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}
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}
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return -1
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}
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func (zone *ZoneDb) MatchLocal(name string) (net.IP, error) {
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zone.mx.RLock()
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defer zone.mx.RUnlock()
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for _, r := range zone.recs {
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if r.Name == name {
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return r.WeaveIP, nil
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}
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}
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return nil, LookupError(name)
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}
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func (zone *ZoneDb) MatchLocalIP(ip net.IP) (string, error) {
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zone.mx.RLock()
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defer zone.mx.RUnlock()
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for _, r := range zone.recs {
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if r.WeaveIP.Equal(ip) {
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return r.Name, nil
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}
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}
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return "", LookupError(ip.String())
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}
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func (zone *ZoneDb) AddRecord(ident string, name string, localIP net.IP, weaveIP net.IP) error {
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zone.mx.Lock()
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defer zone.mx.Unlock()
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fqdn := dns.Fqdn(name)
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if index := zone.indexOf(
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func(r Record) bool { return r.Name == fqdn && r.WeaveIP.Equal(weaveIP) }); index != -1 {
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return DuplicateError{fqdn, weaveIP, zone.recs[index].Ident}
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}
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zone.recs = append(zone.recs, Record{ident, fqdn, localIP, weaveIP})
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return nil
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}
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func (zone *ZoneDb) DeleteRecord(ident string, weaveIP net.IP) error {
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zone.mx.Lock()
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defer zone.mx.Unlock()
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if index := zone.indexOf(
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func(r Record) bool { return r.Ident == ident && r.WeaveIP.Equal(weaveIP) }); index == -1 {
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return LookupError(ident)
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} else {
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zone.recs = append(zone.recs[:index], zone.recs[index+1:]...)
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}
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return nil
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}
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func (zone *ZoneDb) DeleteRecordsFor(ident string) error {
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zone.mx.Lock()
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defer zone.mx.Unlock()
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w := 0 // write index
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for _, r := range zone.recs {
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if r.Ident != ident {
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zone.recs[w] = r
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w++
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}
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}
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zone.recs = zone.recs[:w]
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return nil
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}
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