/
proxy.go
910 lines (872 loc) · 28.6 KB
/
proxy.go
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package main
import (
"context"
crypto_rand "crypto/rand"
"encoding/binary"
"math/rand"
"net"
"os"
"runtime"
"strings"
"sync/atomic"
"time"
"github.com/jedisct1/dlog"
clocksmith "github.com/jedisct1/go-clocksmith"
stamps "github.com/jedisct1/go-dnsstamps"
"github.com/miekg/dns"
"golang.org/x/crypto/curve25519"
)
type Proxy struct {
pluginsGlobals PluginsGlobals
serversInfo ServersInfo
questionSizeEstimator QuestionSizeEstimator
registeredServers []RegisteredServer
dns64Resolvers []string
dns64Prefixes []string
serversBlockingFragments []string
ednsClientSubnets []*net.IPNet
queryLogIgnoredQtypes []string
localDoHListeners []*net.TCPListener
queryMeta []string
udpListeners []*net.UDPConn
sources []*Source
tcpListeners []*net.TCPListener
registeredRelays []RegisteredServer
listenAddresses []string
localDoHListenAddresses []string
xTransport *XTransport
allWeeklyRanges *map[string]WeeklyRanges
routes *map[string][]string
captivePortalMap *CaptivePortalMap
nxLogFormat string
localDoHCertFile string
localDoHCertKeyFile string
captivePortalMapFile string
localDoHPath string
mainProto string
cloakFile string
forwardFile string
blockIPFormat string
blockIPLogFile string
allowedIPFile string
allowedIPFormat string
allowedIPLogFile string
queryLogFormat string
blockIPFile string
allowNameFile string
allowNameFormat string
allowNameLogFile string
blockNameLogFile string
blockNameFormat string
blockNameFile string
queryLogFile string
blockedQueryResponse string
userName string
nxLogFile string
proxySecretKey [32]byte
proxyPublicKey [32]byte
ServerNames []string
DisabledServerNames []string
requiredProps stamps.ServerInformalProperties
certRefreshDelayAfterFailure time.Duration
timeout time.Duration
certRefreshDelay time.Duration
certRefreshConcurrency int
cacheSize int
logMaxBackups int
logMaxAge int
logMaxSize int
cacheNegMinTTL uint32
rejectTTL uint32
cacheMaxTTL uint32
clientsCount uint32
maxClients uint32
cacheMinTTL uint32
cacheNegMaxTTL uint32
cloakTTL uint32
cloakedPTR bool
cache bool
pluginBlockIPv6 bool
ephemeralKeys bool
pluginBlockUnqualified bool
showCerts bool
certIgnoreTimestamp bool
skipAnonIncompatibleResolvers bool
anonDirectCertFallback bool
pluginBlockUndelegated bool
child bool
SourceIPv4 bool
SourceIPv6 bool
SourceDNSCrypt bool
SourceDoH bool
SourceODoH bool
}
func (proxy *Proxy) registerUDPListener(conn *net.UDPConn) {
proxy.udpListeners = append(proxy.udpListeners, conn)
}
func (proxy *Proxy) registerTCPListener(listener *net.TCPListener) {
proxy.tcpListeners = append(proxy.tcpListeners, listener)
}
func (proxy *Proxy) registerLocalDoHListener(listener *net.TCPListener) {
proxy.localDoHListeners = append(proxy.localDoHListeners, listener)
}
func (proxy *Proxy) addDNSListener(listenAddrStr string) {
udp := "udp"
tcp := "tcp"
isIPv4 := isDigit(listenAddrStr[0])
if isIPv4 {
udp = "udp4"
tcp = "tcp4"
}
listenUDPAddr, err := net.ResolveUDPAddr(udp, listenAddrStr)
if err != nil {
dlog.Fatal(err)
}
listenTCPAddr, err := net.ResolveTCPAddr(tcp, listenAddrStr)
if err != nil {
dlog.Fatal(err)
}
// if 'userName' is not set, continue as before
if len(proxy.userName) <= 0 {
if err := proxy.udpListenerFromAddr(listenUDPAddr); err != nil {
dlog.Fatal(err)
}
if err := proxy.tcpListenerFromAddr(listenTCPAddr); err != nil {
dlog.Fatal(err)
}
return
}
// if 'userName' is set and we are the parent process
if !proxy.child {
// parent
listenerUDP, err := net.ListenUDP(udp, listenUDPAddr)
if err != nil {
dlog.Fatal(err)
}
listenerTCP, err := net.ListenTCP(tcp, listenTCPAddr)
if err != nil {
dlog.Fatal(err)
}
fdUDP, err := listenerUDP.File() // On Windows, the File method of UDPConn is not implemented.
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
fdTCP, err := listenerTCP.File() // On Windows, the File method of TCPListener is not implemented.
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
defer listenerUDP.Close()
defer listenerTCP.Close()
FileDescriptors = append(FileDescriptors, fdUDP)
FileDescriptors = append(FileDescriptors, fdTCP)
return
}
// child
listenerUDP, err := net.FilePacketConn(os.NewFile(InheritedDescriptorsBase+FileDescriptorNum, "listenerUDP"))
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
FileDescriptorNum++
listenerTCP, err := net.FileListener(os.NewFile(InheritedDescriptorsBase+FileDescriptorNum, "listenerTCP"))
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
FileDescriptorNum++
dlog.Noticef("Now listening to %v [UDP]", listenUDPAddr)
proxy.registerUDPListener(listenerUDP.(*net.UDPConn))
dlog.Noticef("Now listening to %v [TCP]", listenAddrStr)
proxy.registerTCPListener(listenerTCP.(*net.TCPListener))
}
func (proxy *Proxy) addLocalDoHListener(listenAddrStr string) {
network := "tcp"
isIPv4 := isDigit(listenAddrStr[0])
if isIPv4 {
network = "tcp4"
}
listenTCPAddr, err := net.ResolveTCPAddr(network, listenAddrStr)
if err != nil {
dlog.Fatal(err)
}
// if 'userName' is not set, continue as before
if len(proxy.userName) <= 0 {
if err := proxy.localDoHListenerFromAddr(listenTCPAddr); err != nil {
dlog.Fatal(err)
}
return
}
// if 'userName' is set and we are the parent process
if !proxy.child {
// parent
listenerTCP, err := net.ListenTCP(network, listenTCPAddr)
if err != nil {
dlog.Fatal(err)
}
fdTCP, err := listenerTCP.File() // On Windows, the File method of TCPListener is not implemented.
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
defer listenerTCP.Close()
FileDescriptors = append(FileDescriptors, fdTCP)
return
}
// child
listenerTCP, err := net.FileListener(os.NewFile(InheritedDescriptorsBase+FileDescriptorNum, "listenerTCP"))
if err != nil {
dlog.Fatalf("Unable to switch to a different user: %v", err)
}
FileDescriptorNum++
proxy.registerLocalDoHListener(listenerTCP.(*net.TCPListener))
dlog.Noticef("Now listening to https://%v%v [DoH]", listenAddrStr, proxy.localDoHPath)
}
func (proxy *Proxy) StartProxy() {
proxy.questionSizeEstimator = NewQuestionSizeEstimator()
if _, err := crypto_rand.Read(proxy.proxySecretKey[:]); err != nil {
dlog.Fatal(err)
}
curve25519.ScalarBaseMult(&proxy.proxyPublicKey, &proxy.proxySecretKey)
proxy.startAcceptingClients()
if !proxy.child {
// Notify the service manager that dnscrypt-proxy is ready. dnscrypt-proxy manages itself in case
// servers are not immediately live/reachable. The service manager may assume it is initialized and
// functioning properly. Note that the service manager 'Ready' signal is delayed if netprobe
// cannot reach the internet during start-up.
if err := ServiceManagerReadyNotify(); err != nil {
dlog.Fatal(err)
}
}
proxy.xTransport.internalResolverReady = false
proxy.xTransport.internalResolvers = proxy.listenAddresses
liveServers, err := proxy.serversInfo.refresh(proxy)
if liveServers > 0 {
proxy.certIgnoreTimestamp = false
}
if proxy.showCerts {
os.Exit(0)
}
if liveServers > 0 {
dlog.Noticef("dnscrypt-proxy is ready - live servers: %d", liveServers)
} else if err != nil {
dlog.Error(err)
dlog.Notice("dnscrypt-proxy is waiting for at least one server to be reachable")
}
go func() {
for {
clocksmith.Sleep(PrefetchSources(proxy.xTransport, proxy.sources))
proxy.updateRegisteredServers()
runtime.GC()
}
}()
if len(proxy.serversInfo.registeredServers) > 0 {
go func() {
for {
delay := proxy.certRefreshDelay
if liveServers == 0 {
delay = proxy.certRefreshDelayAfterFailure
}
clocksmith.Sleep(delay)
liveServers, _ = proxy.serversInfo.refresh(proxy)
if liveServers > 0 {
proxy.certIgnoreTimestamp = false
}
runtime.GC()
}
}()
}
}
func (proxy *Proxy) updateRegisteredServers() error {
for _, source := range proxy.sources {
registeredServers, err := source.Parse()
if err != nil {
if len(registeredServers) == 0 {
dlog.Criticalf("Unable to use source [%s]: [%s]", source.name, err)
return err
}
dlog.Warnf(
"Error in source [%s]: [%s] -- Continuing with reduced server count [%d]",
source.name,
err,
len(registeredServers),
)
}
for _, registeredServer := range registeredServers {
if registeredServer.stamp.Proto != stamps.StampProtoTypeDNSCryptRelay &&
registeredServer.stamp.Proto != stamps.StampProtoTypeODoHRelay {
if len(proxy.ServerNames) > 0 {
if !includesName(proxy.ServerNames, registeredServer.name) {
continue
}
} else if registeredServer.stamp.Props&proxy.requiredProps != proxy.requiredProps {
continue
}
}
if includesName(proxy.DisabledServerNames, registeredServer.name) {
continue
}
if proxy.SourceIPv4 || proxy.SourceIPv6 {
isIPv4, isIPv6 := true, false
if registeredServer.stamp.Proto == stamps.StampProtoTypeDoH {
isIPv4, isIPv6 = true, true
}
if strings.HasPrefix(registeredServer.stamp.ServerAddrStr, "[") {
isIPv4, isIPv6 = false, true
}
if !(proxy.SourceIPv4 == isIPv4 || proxy.SourceIPv6 == isIPv6) {
continue
}
}
if registeredServer.stamp.Proto == stamps.StampProtoTypeDNSCryptRelay ||
registeredServer.stamp.Proto == stamps.StampProtoTypeODoHRelay {
var found bool
for i, currentRegisteredRelay := range proxy.registeredRelays {
if currentRegisteredRelay.name == registeredServer.name {
found = true
if currentRegisteredRelay.stamp.String() != registeredServer.stamp.String() {
dlog.Infof(
"Updating stamp for [%s] was: %s now: %s",
registeredServer.name,
currentRegisteredRelay.stamp.String(),
registeredServer.stamp.String(),
)
proxy.registeredRelays[i].stamp = registeredServer.stamp
dlog.Debugf("Total count of registered relays %v", len(proxy.registeredRelays))
}
}
}
if !found {
dlog.Debugf("Adding [%s] to the set of available relays", registeredServer.name)
proxy.registeredRelays = append(proxy.registeredRelays, registeredServer)
}
} else {
if !((proxy.SourceDNSCrypt && registeredServer.stamp.Proto == stamps.StampProtoTypeDNSCrypt) ||
(proxy.SourceDoH && registeredServer.stamp.Proto == stamps.StampProtoTypeDoH) ||
(proxy.SourceODoH && registeredServer.stamp.Proto == stamps.StampProtoTypeODoHTarget)) {
continue
}
var found bool
for i, currentRegisteredServer := range proxy.registeredServers {
if currentRegisteredServer.name == registeredServer.name {
found = true
if currentRegisteredServer.stamp.String() != registeredServer.stamp.String() {
dlog.Infof("Updating stamp for [%s] was: %s now: %s", registeredServer.name, currentRegisteredServer.stamp.String(), registeredServer.stamp.String())
proxy.registeredServers[i].stamp = registeredServer.stamp
}
}
}
if !found {
dlog.Debugf("Adding [%s] to the set of wanted resolvers", registeredServer.name)
proxy.registeredServers = append(proxy.registeredServers, registeredServer)
dlog.Debugf("Total count of registered servers %v", len(proxy.registeredServers))
}
}
}
}
for _, registeredServer := range proxy.registeredServers {
proxy.serversInfo.registerServer(registeredServer.name, registeredServer.stamp)
}
for _, registeredRelay := range proxy.registeredRelays {
proxy.serversInfo.registerRelay(registeredRelay.name, registeredRelay.stamp)
}
return nil
}
func (proxy *Proxy) udpListener(clientPc *net.UDPConn) {
defer clientPc.Close()
for {
buffer := make([]byte, MaxDNSPacketSize-1)
length, clientAddr, err := clientPc.ReadFrom(buffer)
if err != nil {
return
}
packet := buffer[:length]
if !proxy.clientsCountInc() {
dlog.Warnf("Too many incoming connections (max=%d)", proxy.maxClients)
proxy.processIncomingQuery(
"udp",
proxy.mainProto,
packet,
&clientAddr,
clientPc,
time.Now(),
true,
) // respond synchronously, but only to cached/synthesized queries
continue
}
go func() {
defer proxy.clientsCountDec()
proxy.processIncomingQuery("udp", proxy.mainProto, packet, &clientAddr, clientPc, time.Now(), false)
}()
}
}
func (proxy *Proxy) tcpListener(acceptPc *net.TCPListener) {
defer acceptPc.Close()
for {
clientPc, err := acceptPc.Accept()
if err != nil {
continue
}
if !proxy.clientsCountInc() {
dlog.Warnf("Too many incoming connections (max=%d)", proxy.maxClients)
clientPc.Close()
continue
}
go func() {
defer clientPc.Close()
defer proxy.clientsCountDec()
if err := clientPc.SetDeadline(time.Now().Add(proxy.timeout)); err != nil {
return
}
start := time.Now()
packet, err := ReadPrefixed(&clientPc)
if err != nil {
return
}
clientAddr := clientPc.RemoteAddr()
proxy.processIncomingQuery("tcp", "tcp", packet, &clientAddr, clientPc, start, false)
}()
}
}
func (proxy *Proxy) udpListenerFromAddr(listenAddr *net.UDPAddr) error {
listenConfig, err := proxy.udpListenerConfig()
if err != nil {
return err
}
listenAddrStr := listenAddr.String()
network := "udp"
isIPv4 := isDigit(listenAddrStr[0])
if isIPv4 {
network = "udp4"
}
clientPc, err := listenConfig.ListenPacket(context.Background(), network, listenAddrStr)
if err != nil {
return err
}
proxy.registerUDPListener(clientPc.(*net.UDPConn))
dlog.Noticef("Now listening to %v [UDP]", listenAddr)
return nil
}
func (proxy *Proxy) tcpListenerFromAddr(listenAddr *net.TCPAddr) error {
listenConfig, err := proxy.tcpListenerConfig()
if err != nil {
return err
}
listenAddrStr := listenAddr.String()
network := "tcp"
isIPv4 := isDigit(listenAddrStr[0])
if isIPv4 {
network = "tcp4"
}
acceptPc, err := listenConfig.Listen(context.Background(), network, listenAddrStr)
if err != nil {
return err
}
proxy.registerTCPListener(acceptPc.(*net.TCPListener))
dlog.Noticef("Now listening to %v [TCP]", listenAddr)
return nil
}
func (proxy *Proxy) localDoHListenerFromAddr(listenAddr *net.TCPAddr) error {
listenConfig, err := proxy.tcpListenerConfig()
if err != nil {
return err
}
listenAddrStr := listenAddr.String()
network := "tcp"
isIPv4 := isDigit(listenAddrStr[0])
if isIPv4 {
network = "tcp4"
}
acceptPc, err := listenConfig.Listen(context.Background(), network, listenAddrStr)
if err != nil {
return err
}
proxy.registerLocalDoHListener(acceptPc.(*net.TCPListener))
dlog.Noticef("Now listening to https://%v%v [DoH]", listenAddr, proxy.localDoHPath)
return nil
}
func (proxy *Proxy) startAcceptingClients() {
for _, clientPc := range proxy.udpListeners {
go proxy.udpListener(clientPc)
}
proxy.udpListeners = nil
for _, acceptPc := range proxy.tcpListeners {
go proxy.tcpListener(acceptPc)
}
proxy.tcpListeners = nil
for _, acceptPc := range proxy.localDoHListeners {
go proxy.localDoHListener(acceptPc)
}
proxy.localDoHListeners = nil
}
func (proxy *Proxy) prepareForRelay(ip net.IP, port int, encryptedQuery *[]byte) {
anonymizedDNSHeader := []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00}
relayedQuery := append(anonymizedDNSHeader, ip.To16()...)
var tmp [2]byte
binary.BigEndian.PutUint16(tmp[0:2], uint16(port))
relayedQuery = append(relayedQuery, tmp[:]...)
relayedQuery = append(relayedQuery, *encryptedQuery...)
*encryptedQuery = relayedQuery
}
func (proxy *Proxy) exchangeWithUDPServer(
serverInfo *ServerInfo,
sharedKey *[32]byte,
encryptedQuery []byte,
clientNonce []byte,
) ([]byte, error) {
upstreamAddr := serverInfo.UDPAddr
if serverInfo.Relay != nil && serverInfo.Relay.Dnscrypt != nil {
upstreamAddr = serverInfo.Relay.Dnscrypt.RelayUDPAddr
}
var err error
var pc net.Conn
proxyDialer := proxy.xTransport.proxyDialer
if proxyDialer == nil {
pc, err = net.DialTimeout("udp", upstreamAddr.String(), serverInfo.Timeout)
} else {
pc, err = (*proxyDialer).Dial("udp", upstreamAddr.String())
}
if err != nil {
return nil, err
}
defer pc.Close()
if err := pc.SetDeadline(time.Now().Add(serverInfo.Timeout)); err != nil {
return nil, err
}
if serverInfo.Relay != nil && serverInfo.Relay.Dnscrypt != nil {
proxy.prepareForRelay(serverInfo.UDPAddr.IP, serverInfo.UDPAddr.Port, &encryptedQuery)
}
encryptedResponse := make([]byte, MaxDNSPacketSize)
for tries := 2; tries > 0; tries-- {
if _, err := pc.Write(encryptedQuery); err != nil {
return nil, err
}
length, err := pc.Read(encryptedResponse)
if err == nil {
encryptedResponse = encryptedResponse[:length]
break
}
dlog.Debugf("[%v] Retry on timeout", serverInfo.Name)
}
return proxy.Decrypt(serverInfo, sharedKey, encryptedResponse, clientNonce)
}
func (proxy *Proxy) exchangeWithTCPServer(
serverInfo *ServerInfo,
sharedKey *[32]byte,
encryptedQuery []byte,
clientNonce []byte,
) ([]byte, error) {
upstreamAddr := serverInfo.TCPAddr
if serverInfo.Relay != nil && serverInfo.Relay.Dnscrypt != nil {
upstreamAddr = serverInfo.Relay.Dnscrypt.RelayTCPAddr
}
var err error
var pc net.Conn
proxyDialer := proxy.xTransport.proxyDialer
if proxyDialer == nil {
pc, err = net.DialTimeout("tcp", upstreamAddr.String(), serverInfo.Timeout)
} else {
pc, err = (*proxyDialer).Dial("tcp", upstreamAddr.String())
}
if err != nil {
return nil, err
}
defer pc.Close()
if err := pc.SetDeadline(time.Now().Add(serverInfo.Timeout)); err != nil {
return nil, err
}
if serverInfo.Relay != nil && serverInfo.Relay.Dnscrypt != nil {
proxy.prepareForRelay(serverInfo.TCPAddr.IP, serverInfo.TCPAddr.Port, &encryptedQuery)
}
encryptedQuery, err = PrefixWithSize(encryptedQuery)
if err != nil {
return nil, err
}
if _, err := pc.Write(encryptedQuery); err != nil {
return nil, err
}
encryptedResponse, err := ReadPrefixed(&pc)
if err != nil {
return nil, err
}
return proxy.Decrypt(serverInfo, sharedKey, encryptedResponse, clientNonce)
}
func (proxy *Proxy) clientsCountInc() bool {
for {
count := atomic.LoadUint32(&proxy.clientsCount)
if count >= proxy.maxClients {
return false
}
if atomic.CompareAndSwapUint32(&proxy.clientsCount, count, count+1) {
dlog.Debugf("clients count: %d", count+1)
return true
}
}
}
func (proxy *Proxy) clientsCountDec() {
for {
if count := atomic.LoadUint32(&proxy.clientsCount); count == 0 ||
atomic.CompareAndSwapUint32(&proxy.clientsCount, count, count-1) {
break
}
}
}
func (proxy *Proxy) processIncomingQuery(
clientProto string,
serverProto string,
query []byte,
clientAddr *net.Addr,
clientPc net.Conn,
start time.Time,
onlyCached bool,
) []byte {
var response []byte
if len(query) < MinDNSPacketSize {
return response
}
pluginsState := NewPluginsState(proxy, clientProto, clientAddr, serverProto, start)
serverName := "-"
needsEDNS0Padding := false
serverInfo := proxy.serversInfo.getOne()
if serverInfo != nil {
serverName = serverInfo.Name
needsEDNS0Padding = (serverInfo.Proto == stamps.StampProtoTypeDoH || serverInfo.Proto == stamps.StampProtoTypeTLS)
}
query, _ = pluginsState.ApplyQueryPlugins(&proxy.pluginsGlobals, query, needsEDNS0Padding)
if len(query) < MinDNSPacketSize || len(query) > MaxDNSPacketSize {
return response
}
if pluginsState.action == PluginsActionDrop {
pluginsState.returnCode = PluginsReturnCodeDrop
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
var err error
if pluginsState.synthResponse != nil {
response, err = pluginsState.synthResponse.PackBuffer(response)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
}
if onlyCached {
if len(response) == 0 {
return response
}
serverInfo = nil
}
if len(response) == 0 && serverInfo != nil {
var ttl *uint32
pluginsState.serverName = serverName
if serverInfo.Proto == stamps.StampProtoTypeDNSCrypt {
sharedKey, encryptedQuery, clientNonce, err := proxy.Encrypt(serverInfo, query, serverProto)
if err != nil && serverProto == "udp" {
dlog.Debug("Unable to pad for UDP, re-encrypting query for TCP")
serverProto = "tcp"
sharedKey, encryptedQuery, clientNonce, err = proxy.Encrypt(serverInfo, query, serverProto)
}
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
serverInfo.noticeBegin(proxy)
if serverProto == "udp" {
response, err = proxy.exchangeWithUDPServer(serverInfo, sharedKey, encryptedQuery, clientNonce)
retryOverTCP := false
if err == nil && len(response) >= MinDNSPacketSize && response[2]&0x02 == 0x02 {
retryOverTCP = true
} else if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
dlog.Debugf("[%v] Retry over TCP after UDP timeouts", serverName)
retryOverTCP = true
}
if retryOverTCP {
serverProto = "tcp"
sharedKey, encryptedQuery, clientNonce, err = proxy.Encrypt(serverInfo, query, serverProto)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
response, err = proxy.exchangeWithTCPServer(serverInfo, sharedKey, encryptedQuery, clientNonce)
}
} else {
response, err = proxy.exchangeWithTCPServer(serverInfo, sharedKey, encryptedQuery, clientNonce)
}
if err != nil {
if stale, ok := pluginsState.sessionData["stale"]; ok {
dlog.Debug("Serving stale response")
response, err = (stale.(*dns.Msg)).Pack()
}
}
if err != nil {
if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
pluginsState.returnCode = PluginsReturnCodeServerTimeout
} else {
pluginsState.returnCode = PluginsReturnCodeNetworkError
}
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
serverInfo.noticeFailure(proxy)
return response
}
} else if serverInfo.Proto == stamps.StampProtoTypeDoH {
tid := TransactionID(query)
SetTransactionID(query, 0)
serverInfo.noticeBegin(proxy)
serverResponse, _, tls, _, err := proxy.xTransport.DoHQuery(serverInfo.useGet, serverInfo.URL, query, proxy.timeout)
SetTransactionID(query, tid)
if err != nil || tls == nil || !tls.HandshakeComplete {
if stale, ok := pluginsState.sessionData["stale"]; ok {
dlog.Debug("Serving stale response")
response, err = (stale.(*dns.Msg)).Pack()
}
}
if err != nil {
pluginsState.returnCode = PluginsReturnCodeNetworkError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
serverInfo.noticeFailure(proxy)
return response
}
if response == nil {
response = serverResponse
}
if len(response) >= MinDNSPacketSize {
SetTransactionID(response, tid)
}
} else if serverInfo.Proto == stamps.StampProtoTypeODoHTarget {
tid := TransactionID(query)
if len(serverInfo.odohTargetConfigs) == 0 {
return response
}
target := serverInfo.odohTargetConfigs[rand.Intn(len(serverInfo.odohTargetConfigs))]
odohQuery, err := target.encryptQuery(query)
if err != nil {
dlog.Errorf("Failed to encrypt query for [%v]", serverName)
response = nil
} else {
targetURL := serverInfo.URL
if serverInfo.Relay != nil && serverInfo.Relay.ODoH != nil {
targetURL = serverInfo.Relay.ODoH.URL
}
responseBody, responseCode, _, _, err := proxy.xTransport.ObliviousDoHQuery(serverInfo.useGet, targetURL, odohQuery.odohMessage, proxy.timeout)
if err == nil && len(responseBody) > 0 && responseCode == 200 {
response, err = odohQuery.decryptResponse(responseBody)
if err != nil {
dlog.Warnf("Failed to decrypt response from [%v]", serverName)
response = nil
}
} else if responseCode == 401 || (responseCode == 200 && len(responseBody) == 0) {
if responseCode == 200 {
dlog.Warnf("ODoH relay for [%v] is buggy and returns a 200 status code instead of 401 after a key update", serverInfo.Name)
}
dlog.Infof("Forcing key update for [%v]", serverInfo.Name)
for _, registeredServer := range proxy.serversInfo.registeredServers {
if registeredServer.name == serverInfo.Name {
if err = proxy.serversInfo.refreshServer(proxy, registeredServer.name, registeredServer.stamp); err != nil {
// Failed to refresh the proxy server information.
dlog.Noticef("Key update failed for [%v]", serverName)
serverInfo.noticeFailure(proxy)
clocksmith.Sleep(10 * time.Second)
}
break
}
}
response = nil
} else {
dlog.Warnf("Failed to receive successful response from [%v]", serverName)
}
}
if len(response) >= MinDNSPacketSize {
SetTransactionID(response, tid)
} else if response == nil {
pluginsState.returnCode = PluginsReturnCodeNetworkError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
serverInfo.noticeFailure(proxy)
return response
}
} else {
dlog.Fatal("Unsupported protocol")
}
if len(response) < MinDNSPacketSize || len(response) > MaxDNSPacketSize {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
serverInfo.noticeFailure(proxy)
return response
}
response, err = pluginsState.ApplyResponsePlugins(&proxy.pluginsGlobals, response, ttl)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
serverInfo.noticeFailure(proxy)
return response
}
if pluginsState.action == PluginsActionDrop {
pluginsState.returnCode = PluginsReturnCodeDrop
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
if pluginsState.synthResponse != nil {
response, err = pluginsState.synthResponse.PackBuffer(response)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
}
if rcode := Rcode(response); rcode == dns.RcodeServerFailure { // SERVFAIL
if pluginsState.dnssec {
dlog.Debug("A response had an invalid DNSSEC signature")
} else {
dlog.Infof("A response with status code 2 was received - this is usually a temporary, remote issue with the configuration of the domain name")
serverInfo.noticeFailure(proxy)
}
} else {
serverInfo.noticeSuccess(proxy)
}
}
if len(response) < MinDNSPacketSize || len(response) > MaxDNSPacketSize {
if len(response) == 0 {
pluginsState.returnCode = PluginsReturnCodeNotReady
} else {
pluginsState.returnCode = PluginsReturnCodeParseError
}
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
if serverInfo != nil {
serverInfo.noticeFailure(proxy)
}
return response
}
if clientProto == "udp" {
if len(response) > pluginsState.maxUnencryptedUDPSafePayloadSize {
response, err = TruncatedResponse(response)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
}
clientPc.(net.PacketConn).WriteTo(response, *clientAddr)
if HasTCFlag(response) {
proxy.questionSizeEstimator.blindAdjust()
} else {
proxy.questionSizeEstimator.adjust(ResponseOverhead + len(response))
}
} else if clientProto == "tcp" {
response, err = PrefixWithSize(response)
if err != nil {
pluginsState.returnCode = PluginsReturnCodeParseError
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
if serverInfo != nil {
serverInfo.noticeFailure(proxy)
}
return response
}
if clientPc != nil {
clientPc.Write(response)
}
}
pluginsState.ApplyLoggingPlugins(&proxy.pluginsGlobals)
return response
}
func NewProxy() *Proxy {
return &Proxy{
serversInfo: NewServersInfo(),
}
}