Make the xTransport functions return the HTTP body directly

This simplifies things, but also make RTT computation way more reliable

dnscrypt-proxy/proxy.go

@@ -3,8 +3,6 @@ package main
 import (
 	crypto_rand "crypto/rand"
 	"encoding/binary"
-	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"sync/atomic"
@@ -513,9 +511,9 @@ func (proxy *Proxy) processIncomingQuery(serverInfo *ServerInfo, clientProto str
 			tid := TransactionID(query)
 			SetTransactionID(query, 0)
 			serverInfo.noticeBegin(proxy)
-			resp, _, err := proxy.xTransport.DoHQuery(serverInfo.useGet, serverInfo.URL, query, proxy.timeout)
+			serverResponse, tls, _, err := proxy.xTransport.DoHQuery(serverInfo.useGet, serverInfo.URL, query, proxy.timeout)
 			SetTransactionID(query, tid)
-			if err == nil {
+			if err == nil || tls == nil || !tls.HandshakeComplete {
 				response = nil
 			} else if stale, ok := pluginsState.sessionData["stale"]; ok {
 				dlog.Debug("Serving stale response")
@@ -528,7 +526,7 @@ func (proxy *Proxy) processIncomingQuery(serverInfo *ServerInfo, clientProto str
 				return
 			}
 			if response == nil {
-				response, err = ioutil.ReadAll(io.LimitReader(resp.Body, int64(MaxDNSPacketSize)))
+				response = serverResponse
 			}
 			if err != nil {
 				pluginsState.returnCode = PluginsReturnCodeNetworkError

dnscrypt-proxy/serversInfo.go

@@ -6,8 +6,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"io"
-	"io/ioutil"
 	"math/rand"
 	"net"
 	"net/url"
@@ -381,18 +379,17 @@ func fetchDoHServerInfo(proxy *Proxy, name string, stamp stamps.ServerStamp, isN
 	}
 	body := dohTestPacket(0xcafe)
 	useGet := false
-	if _, _, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout); err != nil {
+	if _, _, _, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout); err != nil {
 		useGet = true
-		if _, _, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout); err != nil {
+		if _, _, _, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout); err != nil {
 			return ServerInfo{}, err
 		}
 		dlog.Debugf("Server [%s] doesn't appear to support POST; falling back to GET requests", name)
 	}
-	resp, rtt, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout)
+	serverResponse, tls, rtt, err := proxy.xTransport.DoHQuery(useGet, url, body, proxy.timeout)
 	if err != nil {
 		return ServerInfo{}, err
 	}
-	tls := resp.TLS
 	if tls == nil || !tls.HandshakeComplete {
 		return ServerInfo{}, errors.New("TLS handshake failed")
 	}
@@ -428,7 +425,7 @@ func fetchDoHServerInfo(proxy *Proxy, name string, stamp stamps.ServerStamp, isN
 	if !found && len(stamp.Hashes) > 0 {
 		return ServerInfo{}, fmt.Errorf("Certificate hash [%x] not found for [%s]", wantedHash, name)
 	}
-	respBody, err := ioutil.ReadAll(io.LimitReader(resp.Body, MaxHTTPBodyLength))
+	respBody := serverResponse
 	if err != nil {
 		return ServerInfo{}, err
 	}

dnscrypt-proxy/sources.go

@@ -3,9 +3,7 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io"
 	"io/ioutil"
-	"net/http"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -132,12 +130,8 @@ func (source *Source) parseURLs(urls []string) {
 }
 
 func fetchFromURL(xTransport *XTransport, u *url.URL) (bin []byte, err error) {
-	var resp *http.Response
+	bin, _, _, err = xTransport.Get(u, "", DefaultTimeout)
-	if resp, _, err = xTransport.Get(u, "", DefaultTimeout); err == nil {
+	return bin, err
-		bin, err = ioutil.ReadAll(io.LimitReader(resp.Body, MaxHTTPBodyLength))
-		resp.Body.Close()
-	}
-	return
 }
 
 func (source *Source) fetchWithCache(xTransport *XTransport, now time.Time) (delay time.Duration, err error) {

dnscrypt-proxy/xtransport.go

@@ -8,6 +8,7 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"errors"
+	"io"
 	"io/ioutil"
 	"math/rand"
 	"net"
@@ -316,7 +317,7 @@ func (xTransport *XTransport) resolveAndUpdateCache(host string) error {
 	return nil
 }
 
-func (xTransport *XTransport) Fetch(method string, url *url.URL, accept string, contentType string, body *[]byte, timeout time.Duration) (*http.Response, time.Duration, error) {
+func (xTransport *XTransport) Fetch(method string, url *url.URL, accept string, contentType string, body *[]byte, timeout time.Duration) ([]byte, *tls.ConnectionState, time.Duration, error) {
 	if timeout <= 0 {
 		timeout = xTransport.timeout
 	}
@@ -338,11 +339,11 @@ func (xTransport *XTransport) Fetch(method string, url *url.URL, accept string,
 	}
 	host, _ := ExtractHostAndPort(url.Host, 0)
 	if xTransport.proxyDialer == nil && strings.HasSuffix(host, ".onion") {
-		return nil, 0, errors.New("Onion service is not reachable without Tor")
+		return nil, nil, 0, errors.New("Onion service is not reachable without Tor")
 	}
 	if err := xTransport.resolveAndUpdateCache(host); err != nil {
 		dlog.Errorf("Unable to resolve [%v] - Make sure that the system resolver works, or that `fallback_resolver` has been set to a resolver that can be reached", host)
-		return nil, 0, err
+		return nil, nil, 0, err
 	}
 	req := &http.Request{
 		Method: method,
@@ -373,19 +374,26 @@ func (xTransport *XTransport) Fetch(method string, url *url.URL, accept string,
 			xTransport.tlsCipherSuite = nil
 			xTransport.rebuildTransport()
 		}
+		return nil, nil, 0, err
 	}
-	return resp, rtt, err
+	tls := resp.TLS
+	bin, err := ioutil.ReadAll(io.LimitReader(resp.Body, MaxHTTPBodyLength))
+	if err != nil {
+		return nil, tls, 0, err
+	}
+	resp.Body.Close()
+	return bin, tls, rtt, err
 }
 
-func (xTransport *XTransport) Get(url *url.URL, accept string, timeout time.Duration) (*http.Response, time.Duration, error) {
+func (xTransport *XTransport) Get(url *url.URL, accept string, timeout time.Duration) ([]byte, *tls.ConnectionState, time.Duration, error) {
 	return xTransport.Fetch("GET", url, accept, "", nil, timeout)
 }
 
-func (xTransport *XTransport) Post(url *url.URL, accept string, contentType string, body *[]byte, timeout time.Duration) (*http.Response, time.Duration, error) {
+func (xTransport *XTransport) Post(url *url.URL, accept string, contentType string, body *[]byte, timeout time.Duration) ([]byte, *tls.ConnectionState, time.Duration, error) {
 	return xTransport.Fetch("POST", url, accept, contentType, body, timeout)
 }
 
-func (xTransport *XTransport) DoHQuery(useGet bool, url *url.URL, body []byte, timeout time.Duration) (*http.Response, time.Duration, error) {
+func (xTransport *XTransport) DoHQuery(useGet bool, url *url.URL, body []byte, timeout time.Duration) ([]byte, *tls.ConnectionState, time.Duration, error) {
 	dataType := "application/dns-message"
 	if useGet {
 		qs := url.Query()