mirror of
https://github.com/AdguardTeam/AdGuardHome.git
synced 2024-11-26 15:05:50 +03:00
125 lines
2.6 KiB
Go
125 lines
2.6 KiB
Go
package home
|
|
|
|
import (
|
|
"fmt"
|
|
"strings"
|
|
"time"
|
|
|
|
"github.com/AdguardTeam/dnsproxy/upstream"
|
|
"github.com/AdguardTeam/golibs/log"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
const (
|
|
rdnsTimeout = 3 * time.Second // max time to wait for rDNS response
|
|
)
|
|
|
|
func initRDNS() {
|
|
var err error
|
|
|
|
bindhost := config.DNS.BindHost
|
|
if config.DNS.BindHost == "0.0.0.0" {
|
|
bindhost = "127.0.0.1"
|
|
}
|
|
resolverAddress := fmt.Sprintf("%s:%d", bindhost, config.DNS.Port)
|
|
|
|
opts := upstream.Options{
|
|
Timeout: rdnsTimeout,
|
|
}
|
|
config.dnsctx.upstream, err = upstream.AddressToUpstream(resolverAddress, opts)
|
|
if err != nil {
|
|
log.Error("upstream.AddressToUpstream: %s", err)
|
|
return
|
|
}
|
|
|
|
config.dnsctx.rdnsIP = make(map[string]bool)
|
|
config.dnsctx.rdnsChannel = make(chan string, 256)
|
|
go asyncRDNSLoop()
|
|
}
|
|
|
|
// Add IP address to the rDNS queue
|
|
func beginAsyncRDNS(ip string) {
|
|
if config.clients.Exists(ip, ClientSourceRDNS) {
|
|
return
|
|
}
|
|
|
|
// add IP to rdnsIP, if not exists
|
|
config.dnsctx.rdnsLock.Lock()
|
|
defer config.dnsctx.rdnsLock.Unlock()
|
|
_, ok := config.dnsctx.rdnsIP[ip]
|
|
if ok {
|
|
return
|
|
}
|
|
config.dnsctx.rdnsIP[ip] = true
|
|
|
|
log.Tracef("Adding %s for rDNS resolve", ip)
|
|
select {
|
|
case config.dnsctx.rdnsChannel <- ip:
|
|
//
|
|
default:
|
|
log.Tracef("rDNS queue is full")
|
|
}
|
|
}
|
|
|
|
// Use rDNS to get hostname by IP address
|
|
func resolveRDNS(ip string) string {
|
|
log.Tracef("Resolving host for %s", ip)
|
|
|
|
req := dns.Msg{}
|
|
req.Id = dns.Id()
|
|
req.RecursionDesired = true
|
|
req.Question = []dns.Question{
|
|
{
|
|
Qtype: dns.TypePTR,
|
|
Qclass: dns.ClassINET,
|
|
},
|
|
}
|
|
var err error
|
|
req.Question[0].Name, err = dns.ReverseAddr(ip)
|
|
if err != nil {
|
|
log.Debug("Error while calling dns.ReverseAddr(%s): %s", ip, err)
|
|
return ""
|
|
}
|
|
|
|
resp, err := config.dnsctx.upstream.Exchange(&req)
|
|
if err != nil {
|
|
log.Debug("Error while making an rDNS lookup for %s: %s", ip, err)
|
|
return ""
|
|
}
|
|
if len(resp.Answer) != 1 {
|
|
log.Debug("No answer for rDNS lookup of %s", ip)
|
|
return ""
|
|
}
|
|
ptr, ok := resp.Answer[0].(*dns.PTR)
|
|
if !ok {
|
|
log.Debug("not a PTR response for %s", ip)
|
|
return ""
|
|
}
|
|
|
|
log.Tracef("PTR response for %s: %s", ip, ptr.String())
|
|
if strings.HasSuffix(ptr.Ptr, ".") {
|
|
ptr.Ptr = ptr.Ptr[:len(ptr.Ptr)-1]
|
|
}
|
|
|
|
return ptr.Ptr
|
|
}
|
|
|
|
// Wait for a signal and then synchronously resolve hostname by IP address
|
|
// Add the hostname:IP pair to "Clients" array
|
|
func asyncRDNSLoop() {
|
|
for {
|
|
var ip string
|
|
ip = <-config.dnsctx.rdnsChannel
|
|
|
|
host := resolveRDNS(ip)
|
|
if len(host) == 0 {
|
|
continue
|
|
}
|
|
|
|
config.dnsctx.rdnsLock.Lock()
|
|
delete(config.dnsctx.rdnsIP, ip)
|
|
config.dnsctx.rdnsLock.Unlock()
|
|
|
|
_, _ = config.clients.AddHost(ip, host, ClientSourceRDNS)
|
|
}
|
|
}
|