106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
package home
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import (
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"encoding/binary"
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"net"
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"time"
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"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
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"github.com/AdguardTeam/golibs/cache"
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"github.com/AdguardTeam/golibs/log"
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)
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// RDNS resolves clients' addresses to enrich their metadata.
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type RDNS struct {
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exchanger dnsforward.RDNSExchanger
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clients *clientsContainer
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// ipCh used to pass client's IP to rDNS workerLoop.
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ipCh chan net.IP
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// ipCache caches the IP addresses to be resolved by rDNS. The resolved
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// address stays here while it's inside clients. After leaving clients
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// the address will be resolved once again. If the address couldn't be
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// resolved, cache prevents further attempts to resolve it for some
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// time.
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ipCache cache.Cache
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}
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// Default rDNS values.
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const (
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defaultRDNSCacheSize = 10000
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defaultRDNSCacheTTL = 1 * 60 * 60
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defaultRDNSIPChSize = 256
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)
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// NewRDNS creates and returns initialized RDNS.
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func NewRDNS(
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exchanger dnsforward.RDNSExchanger,
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clients *clientsContainer,
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) (rDNS *RDNS) {
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rDNS = &RDNS{
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exchanger: exchanger,
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clients: clients,
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ipCache: cache.New(cache.Config{
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EnableLRU: true,
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MaxCount: defaultRDNSCacheSize,
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}),
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ipCh: make(chan net.IP, defaultRDNSIPChSize),
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}
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go rDNS.workerLoop()
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return rDNS
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}
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// Begin adds the ip to the resolving queue if it is not cached or already
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// resolved.
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func (r *RDNS) Begin(ip net.IP) {
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now := uint64(time.Now().Unix())
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if expire := r.ipCache.Get(ip); len(expire) != 0 {
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if binary.BigEndian.Uint64(expire) > now {
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return
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}
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}
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// The cache entry either expired or doesn't exist.
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ttl := make([]byte, 8)
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binary.BigEndian.PutUint64(ttl, now+defaultRDNSCacheTTL)
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r.ipCache.Set(ip, ttl)
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id := ip.String()
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if r.clients.Exists(id, ClientSourceRDNS) {
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return
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}
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select {
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case r.ipCh <- ip:
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log.Tracef("rdns: %q added to queue", ip)
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default:
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log.Tracef("rdns: queue is full")
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}
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}
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// workerLoop handles incoming IP addresses from ipChan and adds it into
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// clients.
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func (r *RDNS) workerLoop() {
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defer log.OnPanic("rdns")
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for ip := range r.ipCh {
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host, err := r.exchanger.Exchange(ip)
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if err != nil {
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log.Debug("rdns: resolving %q: %s", ip, err)
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continue
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}
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if host == "" {
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continue
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}
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// Don't handle any errors since AddHost doesn't return non-nil
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// errors for now.
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_, _ = r.clients.AddHost(ip.String(), host, ClientSourceRDNS)
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}
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}
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