mirror of https://github.com/v2fly/v2ray-core.git
106 lines
2.1 KiB
Go
106 lines
2.1 KiB
Go
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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"v2ray.com/core/app"
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"v2ray.com/core/app/dispatcher"
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"v2ray.com/core/common/log"
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"github.com/miekg/dns"
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)
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const (
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QueryTimeout = time.Second * 8
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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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space app.Space
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hosts map[string]net.IP
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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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hosts: config.Hosts,
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}
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space.InitializeApplication(func() error {
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if !space.HasApp(dispatcher.APP_ID) {
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log.Error("DNS: Dispatcher is not found in the space.")
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return app.ErrMissingApplication
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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().Family().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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if len(config.NameServers) == 0 {
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server.servers = append(server.servers, &LocalNameServer{})
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}
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return nil
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})
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return server
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}
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func (this *CacheServer) Release() {
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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(domain string) []net.IP {
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if ip, found := this.hosts[domain]; found {
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return []net.IP{ip}
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}
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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, open := <-response:
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if !open || a == nil {
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continue
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}
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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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log.Debug("DNS: Returning ", len(a.IPs), " IPs for domain ", domain)
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return a.IPs
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case <-time.After(QueryTimeout):
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}
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}
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log.Debug("DNS: Returning nil for domain ", domain)
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return nil
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}
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