mirror of https://github.com/v2ray/v2ray-core
140 lines
3.1 KiB
Go
140 lines
3.1 KiB
Go
package server
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//go:generate go run $GOPATH/src/v2ray.com/core/tools/generrorgen/main.go -pkg server -path App,DNS,Server
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import (
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"context"
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"sync"
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"time"
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dnsmsg "github.com/miekg/dns"
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"v2ray.com/core/app"
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"v2ray.com/core/app/dispatcher"
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"v2ray.com/core/app/dns"
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"v2ray.com/core/app/log"
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"v2ray.com/core/common"
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"v2ray.com/core/common/net"
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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 Record struct {
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IP []net.IP
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Expire time.Time
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LastAccess time.Time
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}
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func (r *Record) Expired() bool {
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now := time.Now()
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return r.Expire.Before(now) || r.LastAccess.Add(time.Hour).Before(now)
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}
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type CacheServer struct {
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sync.RWMutex
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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(ctx context.Context, config *dns.Config) (*CacheServer, error) {
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space := app.SpaceFromContext(ctx)
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if space == nil {
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return nil, newError("no space in context")
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}
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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.GetInternalHosts(),
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}
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space.OnInitialize(func() error {
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disp := dispatcher.FromSpace(space)
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if disp == nil {
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return newError("dispatcher is not found in the space")
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}
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for idx, destPB := range config.NameServers {
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address := destPB.Address.AsAddress()
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if address.Family().IsDomain() && address.Domain() == "localhost" {
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server.servers[idx] = &LocalNameServer{}
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} else {
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dest := destPB.AsDestination()
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if dest.Network == net.Network_Unknown {
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dest.Network = net.Network_UDP
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}
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if dest.Network == net.Network_UDP {
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server.servers[idx] = NewUDPNameServer(dest, disp)
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}
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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, nil
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}
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func (*CacheServer) Interface() interface{} {
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return (*dns.Server)(nil)
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}
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func (*CacheServer) Start() error {
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return nil
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}
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func (*CacheServer) Close() {}
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func (s *CacheServer) GetCached(domain string) []net.IP {
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s.RLock()
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defer s.RUnlock()
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if record, found := s.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 (s *CacheServer) Get(domain string) []net.IP {
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if ip, found := s.hosts[domain]; found {
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return []net.IP{ip}
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}
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domain = dnsmsg.Fqdn(domain)
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ips := s.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 s.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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s.Lock()
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s.records[domain] = &DomainRecord{
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A: a,
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}
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s.Unlock()
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log.Trace(newError("returning ", len(a.IPs), " IPs for domain ", domain).AtDebug())
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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.Trace(newError("returning nil for domain ", domain).AtDebug())
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return nil
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}
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func init() {
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common.Must(common.RegisterConfig((*dns.Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
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return NewCacheServer(ctx, config.(*dns.Config))
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}))
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}
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