108 lines
2.7 KiB
Go
108 lines
2.7 KiB
Go
package dnsforward
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import (
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"fmt"
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"net"
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"github.com/AdguardTeam/AdGuardHome/internal/agherr"
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"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
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"github.com/AdguardTeam/dnsproxy/proxy"
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"github.com/AdguardTeam/golibs/log"
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"github.com/AdguardTeam/urlfilter/rules"
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"github.com/miekg/dns"
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)
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// filterDNSRewriteResponse handles a single DNS rewrite response entry.
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// It returns the properly constructed answer resource record.
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func (s *Server) filterDNSRewriteResponse(req *dns.Msg, rr rules.RRType, v rules.RRValue) (ans dns.RR, err error) {
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// TODO(a.garipov): As more types are added, we will probably want to
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// use a handler-oriented approach here. So, think of a way to decouple
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// the answer generation logic from the Server.
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switch rr {
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case dns.TypeA, dns.TypeAAAA:
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ip, ok := v.(net.IP)
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if !ok {
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return nil, fmt.Errorf("value for rr type %d has type %T, not net.IP", rr, v)
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}
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if rr == dns.TypeA {
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return s.genAnswerA(req, ip.To4()), nil
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}
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return s.genAnswerAAAA(req, ip), nil
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case dns.TypePTR,
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dns.TypeTXT:
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str, ok := v.(string)
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if !ok {
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return nil, fmt.Errorf("value for rr type %d has type %T, not string", rr, v)
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}
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if rr == dns.TypeTXT {
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return s.genAnswerTXT(req, []string{str}), nil
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}
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return s.genAnswerPTR(req, str), nil
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case dns.TypeMX:
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mx, ok := v.(*rules.DNSMX)
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if !ok {
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return nil, fmt.Errorf("value for rr type %d has type %T, not *rules.DNSMX", rr, v)
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}
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return s.genAnswerMX(req, mx), nil
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case dns.TypeHTTPS,
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dns.TypeSVCB:
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svcb, ok := v.(*rules.DNSSVCB)
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if !ok {
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return nil, fmt.Errorf("value for rr type %d has type %T, not *rules.DNSSVCB", rr, v)
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}
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if rr == dns.TypeHTTPS {
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return s.genAnswerHTTPS(req, svcb), nil
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}
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return s.genAnswerSVCB(req, svcb), nil
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default:
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log.Debug("don't know how to handle dns rr type %d, skipping", rr)
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return nil, nil
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}
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}
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// filterDNSRewrite handles dnsrewrite filters. It constructs a DNS
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// response and sets it into d.Res.
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func (s *Server) filterDNSRewrite(req *dns.Msg, res dnsfilter.Result, d *proxy.DNSContext) (err error) {
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resp := s.makeResponse(req)
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dnsrr := res.DNSRewriteResult
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if dnsrr == nil {
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return agherr.Error("no dns rewrite rule content")
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}
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resp.Rcode = dnsrr.RCode
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if resp.Rcode != dns.RcodeSuccess {
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d.Res = resp
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return nil
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}
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if dnsrr.Response == nil {
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return agherr.Error("no dns rewrite rule responses")
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}
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rr := req.Question[0].Qtype
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values := dnsrr.Response[rr]
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for i, v := range values {
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var ans dns.RR
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ans, err = s.filterDNSRewriteResponse(req, rr, v)
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if err != nil {
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return fmt.Errorf("dns rewrite response for %d[%d]: %w", rr, i, err)
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}
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resp.Answer = append(resp.Answer, ans)
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}
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d.Res = resp
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return nil
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}
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