mirror of
https://github.com/DNSCrypt/dnscrypt-proxy.git
synced 2025-04-03 13:17:37 +03:00
d8b1f4e7cd
Found by running: golangci-lint run --enable-all I have only addressed the reported issues that seemed relevant to me.
401 lines
12 KiB
Go
401 lines
12 KiB
Go
package main
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import (
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"errors"
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"net"
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"strings"
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"sync"
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"time"
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"github.com/jedisct1/dlog"
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"github.com/miekg/dns"
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)
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type PluginsAction int
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const (
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PluginsActionNone = 0
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PluginsActionContinue = 1
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PluginsActionDrop = 2
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PluginsActionReject = 3
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PluginsActionSynth = 4
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)
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type PluginsGlobals struct {
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sync.RWMutex
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queryPlugins *[]Plugin
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responsePlugins *[]Plugin
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loggingPlugins *[]Plugin
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refusedCodeInResponses bool
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respondWithIPv4 net.IP
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respondWithIPv6 net.IP
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}
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type PluginsReturnCode int
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const (
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PluginsReturnCodePass = iota
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PluginsReturnCodeForward
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PluginsReturnCodeDrop
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PluginsReturnCodeReject
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PluginsReturnCodeSynth
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PluginsReturnCodeParseError
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PluginsReturnCodeNXDomain
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PluginsReturnCodeResponseError
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PluginsReturnCodeServFail
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PluginsReturnCodeNetworkError
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PluginsReturnCodeCloak
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PluginsReturnCodeServerTimeout
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PluginsReturnCodeNotReady
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)
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var PluginsReturnCodeToString = map[PluginsReturnCode]string{
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PluginsReturnCodePass: "PASS",
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PluginsReturnCodeForward: "FORWARD",
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PluginsReturnCodeDrop: "DROP",
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PluginsReturnCodeReject: "REJECT",
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PluginsReturnCodeSynth: "SYNTH",
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PluginsReturnCodeParseError: "PARSE_ERROR",
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PluginsReturnCodeNXDomain: "NXDOMAIN",
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PluginsReturnCodeResponseError: "RESPONSE_ERROR",
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PluginsReturnCodeServFail: "SERVFAIL",
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PluginsReturnCodeNetworkError: "NETWORK_ERROR",
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PluginsReturnCodeCloak: "CLOAK",
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PluginsReturnCodeServerTimeout: "SERVER_TIMEOUT",
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PluginsReturnCodeNotReady: "NOT_READY",
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}
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type PluginsState struct {
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requestStart time.Time
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requestEnd time.Time
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clientProto string
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serverName string
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serverProto string
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qName string
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clientAddr *net.Addr
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synthResponse *dns.Msg
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questionMsg *dns.Msg
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sessionData map[string]interface{}
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action PluginsAction
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timeout time.Duration
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returnCode PluginsReturnCode
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maxPayloadSize int
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cacheSize int
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originalMaxPayloadSize int
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maxUnencryptedUDPSafePayloadSize int
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rejectTTL uint32
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cacheMaxTTL uint32
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cacheNegMaxTTL uint32
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cacheNegMinTTL uint32
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cacheMinTTL uint32
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cacheHit bool
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dnssec bool
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}
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func (proxy *Proxy) InitPluginsGlobals() error {
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queryPlugins := &[]Plugin{}
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if proxy.captivePortalMap != nil {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginCaptivePortal)))
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}
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if len(proxy.queryMeta) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginQueryMeta)))
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}
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if len(proxy.allowNameFile) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginAllowName)))
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}
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginFirefox)))
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if len(proxy.ednsClientSubnets) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginECS)))
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}
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if len(proxy.blockNameFile) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginBlockName)))
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}
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if proxy.pluginBlockIPv6 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginBlockIPv6)))
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}
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if len(proxy.cloakFile) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginCloak)))
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}
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginGetSetPayloadSize)))
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if proxy.cache {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginCache)))
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}
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if len(proxy.forwardFile) != 0 {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginForward)))
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}
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if proxy.pluginBlockUnqualified {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginBlockUnqualified)))
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}
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if proxy.pluginBlockUndelegated {
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*queryPlugins = append(*queryPlugins, Plugin(new(PluginBlockUndelegated)))
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}
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responsePlugins := &[]Plugin{}
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if len(proxy.nxLogFile) != 0 {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginNxLog)))
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}
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if len(proxy.allowedIPFile) != 0 {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginAllowedIP)))
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}
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if len(proxy.blockNameFile) != 0 {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginBlockNameResponse)))
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}
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if len(proxy.blockIPFile) != 0 {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginBlockIP)))
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}
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if len(proxy.dns64Resolvers) != 0 || len(proxy.dns64Prefixes) != 0 {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginDNS64)))
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}
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if proxy.cache {
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*responsePlugins = append(*responsePlugins, Plugin(new(PluginCacheResponse)))
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}
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loggingPlugins := &[]Plugin{}
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if len(proxy.queryLogFile) != 0 {
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*loggingPlugins = append(*loggingPlugins, Plugin(new(PluginQueryLog)))
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}
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for _, plugin := range *queryPlugins {
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if err := plugin.Init(proxy); err != nil {
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return err
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}
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}
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for _, plugin := range *responsePlugins {
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if err := plugin.Init(proxy); err != nil {
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return err
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}
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}
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for _, plugin := range *loggingPlugins {
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if err := plugin.Init(proxy); err != nil {
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return err
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}
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}
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proxy.pluginsGlobals.queryPlugins = queryPlugins
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proxy.pluginsGlobals.responsePlugins = responsePlugins
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proxy.pluginsGlobals.loggingPlugins = loggingPlugins
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parseBlockedQueryResponse(proxy.blockedQueryResponse, &proxy.pluginsGlobals)
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return nil
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}
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// blockedQueryResponse can be 'refused', 'hinfo' or IP responses 'a:IPv4,aaaa:IPv6
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func parseBlockedQueryResponse(blockedResponse string, pluginsGlobals *PluginsGlobals) {
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blockedResponse = StringStripSpaces(strings.ToLower(blockedResponse))
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if strings.HasPrefix(blockedResponse, "a:") {
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blockedIPStrings := strings.Split(blockedResponse, ",")
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pluginsGlobals.respondWithIPv4 = net.ParseIP(strings.TrimPrefix(blockedIPStrings[0], "a:"))
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if pluginsGlobals.respondWithIPv4 == nil {
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dlog.Notice("Error parsing IPv4 response given in blocked_query_response option, defaulting to `hinfo`")
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pluginsGlobals.refusedCodeInResponses = false
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return
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}
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if len(blockedIPStrings) > 1 {
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if strings.HasPrefix(blockedIPStrings[1], "aaaa:") {
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ipv6Response := strings.TrimPrefix(blockedIPStrings[1], "aaaa:")
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if strings.HasPrefix(ipv6Response, "[") {
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ipv6Response = strings.Trim(ipv6Response, "[]")
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}
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pluginsGlobals.respondWithIPv6 = net.ParseIP(ipv6Response)
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if pluginsGlobals.respondWithIPv6 == nil {
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dlog.Notice(
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"Error parsing IPv6 response given in blocked_query_response option, defaulting to IPv4",
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)
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}
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} else {
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dlog.Noticef("Invalid IPv6 response given in blocked_query_response option [%s], the option should take the form 'a:<IPv4>,aaaa:<IPv6>'", blockedIPStrings[1])
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}
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}
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if pluginsGlobals.respondWithIPv6 == nil {
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pluginsGlobals.respondWithIPv6 = pluginsGlobals.respondWithIPv4
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}
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} else {
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switch blockedResponse {
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case "refused":
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pluginsGlobals.refusedCodeInResponses = true
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case "hinfo":
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pluginsGlobals.refusedCodeInResponses = false
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default:
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dlog.Noticef("Invalid blocked_query_response option [%s], defaulting to `hinfo`", blockedResponse)
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pluginsGlobals.refusedCodeInResponses = false
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}
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}
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}
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type Plugin interface {
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Name() string
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Description() string
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Init(proxy *Proxy) error
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Drop() error
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Reload() error
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Eval(pluginsState *PluginsState, msg *dns.Msg) error
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}
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func NewPluginsState(
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proxy *Proxy,
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clientProto string,
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clientAddr *net.Addr,
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serverProto string,
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start time.Time,
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) PluginsState {
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return PluginsState{
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action: PluginsActionContinue,
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returnCode: PluginsReturnCodePass,
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maxPayloadSize: MaxDNSUDPPacketSize - ResponseOverhead,
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clientProto: clientProto,
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clientAddr: clientAddr,
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cacheSize: proxy.cacheSize,
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cacheNegMinTTL: proxy.cacheNegMinTTL,
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cacheNegMaxTTL: proxy.cacheNegMaxTTL,
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cacheMinTTL: proxy.cacheMinTTL,
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cacheMaxTTL: proxy.cacheMaxTTL,
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rejectTTL: proxy.rejectTTL,
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questionMsg: nil,
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qName: "",
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serverName: "-",
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serverProto: serverProto,
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timeout: proxy.timeout,
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requestStart: start,
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maxUnencryptedUDPSafePayloadSize: MaxDNSUDPSafePacketSize,
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sessionData: make(map[string]interface{}),
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}
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}
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func (pluginsState *PluginsState) ApplyQueryPlugins(
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pluginsGlobals *PluginsGlobals,
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packet []byte,
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needsEDNS0Padding bool,
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) ([]byte, error) {
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msg := dns.Msg{}
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if err := msg.Unpack(packet); err != nil {
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return packet, err
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}
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if len(msg.Question) != 1 {
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return packet, errors.New("Unexpected number of questions")
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}
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qName, err := NormalizeQName(msg.Question[0].Name)
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if err != nil {
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return packet, err
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}
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dlog.Debugf("Handling query for [%v]", qName)
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pluginsState.qName = qName
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pluginsState.questionMsg = &msg
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if len(*pluginsGlobals.queryPlugins) == 0 && len(*pluginsGlobals.loggingPlugins) == 0 {
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return packet, nil
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}
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pluginsGlobals.RLock()
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defer pluginsGlobals.RUnlock()
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for _, plugin := range *pluginsGlobals.queryPlugins {
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if err := plugin.Eval(pluginsState, &msg); err != nil {
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pluginsState.action = PluginsActionDrop
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return packet, err
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}
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if pluginsState.action == PluginsActionReject {
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synth := RefusedResponseFromMessage(
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&msg,
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pluginsGlobals.refusedCodeInResponses,
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pluginsGlobals.respondWithIPv4,
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pluginsGlobals.respondWithIPv6,
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pluginsState.rejectTTL,
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)
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pluginsState.synthResponse = synth
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}
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if pluginsState.action != PluginsActionContinue {
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break
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}
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}
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packet2, err := msg.PackBuffer(packet)
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if err != nil {
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return packet, err
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}
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if needsEDNS0Padding && pluginsState.action == PluginsActionContinue {
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padLen := 63 - ((len(packet2) + 63) & 63)
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if paddedPacket2, _ := addEDNS0PaddingIfNoneFound(&msg, packet2, padLen); paddedPacket2 != nil {
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return paddedPacket2, nil
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}
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}
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return packet2, nil
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}
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func (pluginsState *PluginsState) ApplyResponsePlugins(
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pluginsGlobals *PluginsGlobals,
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packet []byte,
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ttl *uint32,
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) ([]byte, error) {
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msg := dns.Msg{Compress: true}
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if err := msg.Unpack(packet); err != nil {
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if len(packet) >= MinDNSPacketSize && HasTCFlag(packet) {
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err = nil
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}
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return packet, err
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}
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switch Rcode(packet) {
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case dns.RcodeSuccess:
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pluginsState.returnCode = PluginsReturnCodePass
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case dns.RcodeNameError:
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pluginsState.returnCode = PluginsReturnCodeNXDomain
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case dns.RcodeServerFailure:
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pluginsState.returnCode = PluginsReturnCodeServFail
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default:
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pluginsState.returnCode = PluginsReturnCodeResponseError
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}
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removeEDNS0Options(&msg)
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pluginsGlobals.RLock()
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defer pluginsGlobals.RUnlock()
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for _, plugin := range *pluginsGlobals.responsePlugins {
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if err := plugin.Eval(pluginsState, &msg); err != nil {
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pluginsState.action = PluginsActionDrop
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return packet, err
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}
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if pluginsState.action == PluginsActionReject {
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synth := RefusedResponseFromMessage(
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&msg,
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pluginsGlobals.refusedCodeInResponses,
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pluginsGlobals.respondWithIPv4,
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pluginsGlobals.respondWithIPv6,
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pluginsState.rejectTTL,
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)
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pluginsState.synthResponse = synth
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}
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if pluginsState.action != PluginsActionContinue {
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break
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}
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}
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if ttl != nil {
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setMaxTTL(&msg, *ttl)
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}
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packet2, err := msg.PackBuffer(packet)
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if err != nil {
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return packet, err
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}
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return packet2, nil
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}
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func (pluginsState *PluginsState) ApplyLoggingPlugins(pluginsGlobals *PluginsGlobals) error {
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if len(*pluginsGlobals.loggingPlugins) == 0 {
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return nil
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}
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pluginsState.requestEnd = time.Now()
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questionMsg := pluginsState.questionMsg
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if questionMsg == nil {
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return errors.New("Question not found")
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}
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pluginsGlobals.RLock()
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defer pluginsGlobals.RUnlock()
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for _, plugin := range *pluginsGlobals.loggingPlugins {
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if err := plugin.Eval(pluginsState, questionMsg); err != nil {
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return err
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}
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}
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return nil
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}
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