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78 lines
1.5 KiB
78 lines
1.5 KiB
package dns
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import (
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"net"
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"sync"
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"time"
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"github.com/v2ray/v2ray-core/app"
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"github.com/v2ray/v2ray-core/app/dispatcher"
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"github.com/miekg/dns"
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)
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const (
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QueryTimeout = time.Second * 2
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)
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type DomainRecord struct {
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A *ARecord
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}
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type CacheServer struct {
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sync.RWMutex
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records map[string]*DomainRecord
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servers []NameServer
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}
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func NewCacheServer(space app.Space, config *Config) *CacheServer {
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server := &CacheServer{
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records: make(map[string]*DomainRecord),
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servers: make([]NameServer, len(config.NameServers)),
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}
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dispatcher := space.GetApp(dispatcher.APP_ID).(dispatcher.PacketDispatcher)
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for idx, ns := range config.NameServers {
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if ns.Address().IsDomain() && ns.Address().Domain() == "localhost" {
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server.servers[idx] = &LocalNameServer{}
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} else {
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server.servers[idx] = NewUDPNameServer(ns, dispatcher)
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}
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}
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return server
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}
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//@Private
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func (this *CacheServer) GetCached(domain string) []net.IP {
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this.RLock()
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defer this.RUnlock()
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if record, found := this.records[domain]; found && record.A.Expire.After(time.Now()) {
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return record.A.IPs
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}
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return nil
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}
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func (this *CacheServer) Get(context app.Context, domain string) []net.IP {
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domain = dns.Fqdn(domain)
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ips := this.GetCached(domain)
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if ips != nil {
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return ips
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}
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for _, server := range this.servers {
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response := server.QueryA(domain)
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select {
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case a := <-response:
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this.Lock()
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this.records[domain] = &DomainRecord{
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A: a,
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}
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this.Unlock()
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return a.IPs
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case <-time.Tick(QueryTimeout):
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}
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}
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return nil
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}
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