Remove nameserver/only package
This commit is contained in:
Daniel
@@ -1,236 +0,0 @@
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package only
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import (
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"context"
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"net"
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"strings"
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"github.com/safing/portbase/database"
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"github.com/safing/portbase/log"
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"github.com/safing/portbase/modules"
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"github.com/safing/portmaster/netenv"
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"github.com/safing/portmaster/network/netutils"
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"github.com/safing/portmaster/resolver"
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"github.com/miekg/dns"
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)
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var (
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module *modules.Module
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dnsServer *dns.Server
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mtDNSRequest = "dns request"
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listenAddress = "127.0.0.1:53"
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ipv4Localhost = net.IPv4(127, 0, 0, 1)
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localhostRRs []dns.RR
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)
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func init() {
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module = modules.Register("nameserver", initLocalhostRRs, start, stop, "core", "resolver", "network", "netenv")
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}
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func initLocalhostRRs() error {
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localhostIPv4, err := dns.NewRR("localhost. 17 IN A 127.0.0.1")
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if err != nil {
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return err
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}
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localhostIPv6, err := dns.NewRR("localhost. 17 IN AAAA ::1")
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if err != nil {
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return err
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}
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localhostRRs = []dns.RR{localhostIPv4, localhostIPv6}
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return nil
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}
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func start() error {
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dnsServer = &dns.Server{Addr: listenAddress, Net: "udp"}
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dns.HandleFunc(".", handleRequestAsMicroTask)
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module.StartServiceWorker("dns resolver", 0, func(ctx context.Context) error {
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err := dnsServer.ListenAndServe()
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if err != nil {
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// check if we are shutting down
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if module.IsStopping() {
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return nil
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}
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}
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return err
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})
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return nil
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}
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func stop() error {
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if dnsServer != nil {
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return dnsServer.Shutdown()
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}
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return nil
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}
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func returnNXDomain(w dns.ResponseWriter, query *dns.Msg) {
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m := new(dns.Msg)
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m.SetRcode(query, dns.RcodeNameError)
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_ = w.WriteMsg(m)
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}
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func returnServerFailure(w dns.ResponseWriter, query *dns.Msg) {
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m := new(dns.Msg)
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m.SetRcode(query, dns.RcodeServerFailure)
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_ = w.WriteMsg(m)
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}
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func handleRequestAsMicroTask(w dns.ResponseWriter, query *dns.Msg) {
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err := module.RunMicroTask(&mtDNSRequest, func(ctx context.Context) error {
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return handleRequest(ctx, w, query)
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})
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if err != nil {
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log.Warningf("nameserver: failed to handle dns request: %s", err)
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}
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}
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func handleRequest(ctx context.Context, w dns.ResponseWriter, query *dns.Msg) error {
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// return with server failure if offline
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if netenv.GetOnlineStatus() == netenv.StatusOffline {
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returnServerFailure(w, query)
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return nil
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}
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// only process first question, that's how everyone does it.
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question := query.Question[0]
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q := &resolver.Query{
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FQDN: question.Name,
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QType: dns.Type(question.Qtype),
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}
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// check class
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if question.Qclass != dns.ClassINET {
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// we only serve IN records, return nxdomain
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returnNXDomain(w, query)
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return nil
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}
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// handle request for localhost
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if strings.HasSuffix(q.FQDN, "localhost.") {
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m := new(dns.Msg)
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m.SetReply(query)
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m.Answer = localhostRRs
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_ = w.WriteMsg(m)
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return nil
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}
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// get addresses
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remoteAddr, ok := w.RemoteAddr().(*net.UDPAddr)
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if !ok {
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log.Warningf("nameserver: could not get remote address of request for %s%s, ignoring", q.FQDN, q.QType)
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return nil
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}
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if !remoteAddr.IP.Equal(ipv4Localhost) {
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// if request is not coming from 127.0.0.1, check if it's really local
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localAddr, ok := w.RemoteAddr().(*net.UDPAddr)
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if !ok {
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log.Warningf("nameserver: could not get local address of request for %s%s, ignoring", q.FQDN, q.QType)
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return nil
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}
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// ignore external request
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if !remoteAddr.IP.Equal(localAddr.IP) {
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log.Warningf("nameserver: external request for %s%s, ignoring", q.FQDN, q.QType)
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return nil
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}
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}
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// check if valid domain name
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if !netutils.IsValidFqdn(q.FQDN) {
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log.Debugf("nameserver: domain name %s is invalid, returning nxdomain", q.FQDN)
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returnNXDomain(w, query)
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return nil
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}
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// start tracer
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ctx, tracer := log.AddTracer(ctx)
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tracer.Tracef("nameserver: handling new request for %s%s from %s:%d", q.FQDN, q.QType, remoteAddr.IP, remoteAddr.Port)
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// TODO: if there are 3 request for the same domain/type in a row, delete all caches of that domain
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// get intel and RRs
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rrCache, err := resolver.Resolve(ctx, q)
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if err != nil {
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// TODO: analyze nxdomain requests, malware could be trying DGA-domains
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tracer.Warningf("nameserver: request for %s%s: %s", q.FQDN, q.QType, err)
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returnNXDomain(w, query)
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return nil
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}
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// save IP addresses to IPInfo
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cnames := make(map[string]string)
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ips := make(map[string]struct{})
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for _, rr := range append(rrCache.Answer, rrCache.Extra...) {
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switch v := rr.(type) {
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case *dns.CNAME:
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cnames[v.Hdr.Name] = v.Target
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case *dns.A:
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ips[v.A.String()] = struct{}{}
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case *dns.AAAA:
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ips[v.AAAA.String()] = struct{}{}
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}
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}
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for ip := range ips {
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record := resolver.ResolvedDomain{
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Domain: q.FQDN,
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}
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// resolve all CNAMEs in the correct order.
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var domain = q.FQDN
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for {
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nextDomain, isCNAME := cnames[domain]
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if !isCNAME {
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break
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}
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record.CNAMEs = append(record.CNAMEs, nextDomain)
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domain = nextDomain
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}
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// get the existing IP info or create a new one
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var save bool
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info, err := resolver.GetIPInfo(ip)
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if err != nil {
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if err != database.ErrNotFound {
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log.Errorf("nameserver: failed to search for IP info record: %s", err)
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}
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info = &resolver.IPInfo{
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IP: ip,
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}
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save = true
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}
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// and the new resolved domain record and save
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if new := info.AddDomain(record); new {
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save = true
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}
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if save {
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if err := info.Save(); err != nil {
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log.Errorf("nameserver: failed to save IP info record: %s", err)
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}
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}
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}
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// reply to query
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m := new(dns.Msg)
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m.SetReply(query)
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m.Answer = rrCache.Answer
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m.Ns = rrCache.Ns
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m.Extra = rrCache.Extra
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_ = w.WriteMsg(m)
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tracer.Debugf("nameserver: returning response %s%s", q.FQDN, q.QType)
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return nil
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}
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