DoH first working version

resolver/resolver-https.go

@@ -0,0 +1,116 @@
+package resolver
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+
+	"github.com/miekg/dns"
+)
+
+// TCPResolver is a resolver using just a single tcp connection with pipelining.
+type HttpsResolver struct {
+	BasicResolverConn
+}
+
+// tcpQuery holds the query information for a tcpResolverConn.
+type HttpsQuery struct {
+	Query    *Query
+	Response chan *dns.Msg
+}
+
+// MakeCacheRecord creates an RRCache record from a reply.
+func (tq *HttpsQuery) MakeCacheRecord(reply *dns.Msg, resolverInfo *ResolverInfo) *RRCache {
+	return &RRCache{
+		Domain:   tq.Query.FQDN,
+		Question: tq.Query.QType,
+		RCode:    reply.Rcode,
+		Answer:   reply.Answer,
+		Ns:       reply.Ns,
+		Extra:    reply.Extra,
+		Resolver: resolverInfo.Copy(),
+	}
+}
+
+// NewTCPResolver returns a new TPCResolver.
+func NewHttpsResolver(resolver *Resolver) *HttpsResolver {
+	newResolver := &HttpsResolver{
+		BasicResolverConn: BasicResolverConn{
+			resolver: resolver,
+		},
+	}
+	newResolver.BasicResolverConn.init()
+	return newResolver
+}
+
+// Query executes the given query against the resolver.
+func (hr *HttpsResolver) Query(ctx context.Context, q *Query) (*RRCache, error) {
+	// Get resolver connection.
+	dnsQuery := new(dns.Msg)
+	dnsQuery.SetQuestion(q.FQDN, uint16(q.QType))
+
+	buf, err := dnsQuery.Pack()
+
+	if err != nil {
+		return nil, err
+	}
+
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{
+			MinVersion: tls.VersionTLS12,
+			ServerName: hr.resolver.VerifyDomain,
+			// TODO: use portbase rng
+		},
+	}
+
+	b64dns := base64.RawStdEncoding.EncodeToString(buf)
+
+	url := &url.URL{
+		Scheme:     "https",
+		Host:       hr.resolver.ServerAddress,
+		Path:       fmt.Sprintf("%s/dns-query", hr.resolver.Path), // "dns-query" path is specified in rfc-8484 (https://www.rfc-editor.org/rfc/rfc8484.html)
+		ForceQuery: true,
+		RawQuery:   fmt.Sprintf("dns=%s", b64dns),
+	}
+
+	request := &http.Request{
+		Method:     "GET",
+		URL:        url,
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     make(http.Header),
+		Body:       nil,
+		Host:       hr.resolver.ServerAddress,
+	}
+
+	client := &http.Client{Transport: tr}
+
+	resp, err := client.Do(request)
+
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	reply := new(dns.Msg)
+	reply.Unpack(body)
+
+	newRecord := &RRCache{
+		Domain:   q.FQDN,
+		Question: q.QType,
+		RCode:    reply.Rcode,
+		Answer:   reply.Answer,
+		Ns:       reply.Ns,
+		Extra:    reply.Extra,
+		Resolver: hr.resolver.Info.Copy(),
+	}
+
+	// TODO: check if reply.Answer is valid
+	return newRecord, nil
+}