From eac353cf75a66917a29b15b8a0d6f7c80a8bb08e Mon Sep 17 00:00:00 2001
From: Nate Sales <nate@natesales.net>
Date: Tue, 19 Dec 2023 22:14:07 -0800
Subject: [PATCH] feat: add http2 flag (#81)

---
 README.md         |  1 +
 cli/cli.go        |  2 +-
 resolver.go       |  1 +
 transport/http.go | 24 ++++++++++++++++--------
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 8a0b945..a4763ae 100644
--- a/README.md
+++ b/README.md
@@ -48,6 +48,7 @@ Application Options:
   -p, --odoh-proxy=               ODoH proxy
       --timeout=                  Query timeout (default: 10s)
       --pad                       Set EDNS0 padding
+      --http2                     Use HTTP/2 for DoH
       --http3                     Use HTTP/3 for DoH
       --id-check                  Check DNS response ID (default: true)
       --reuse-conn                Reuse connections across queries to the same
diff --git a/cli/cli.go b/cli/cli.go
index 3fc7406..1d8ca26 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -24,6 +24,7 @@ type Flags struct {
 	ODoHProxy        string        `short:"p" long:"odoh-proxy" description:"ODoH proxy"`
 	Timeout          time.Duration `long:"timeout" description:"Query timeout" default:"10s"`
 	Pad              bool          `long:"pad" description:"Set EDNS0 padding"`
+	HTTP2            bool          `long:"http2" description:"Use HTTP/2 for DoH"`
 	HTTP3            bool          `long:"http3" description:"Use HTTP/3 for DoH"`
 	IDCheck          bool          `long:"id-check" description:"Check DNS response ID (default: true)"`
 	ReuseConn        bool          `long:"reuse-conn" description:"Reuse connections across queries to the same server (default: true)"`
@@ -151,7 +152,6 @@ func SetFalseBooleans(opts *Flags, args []string) []string {
 
 	var remainingArgs []string
 	for _, arg := range args {
-
 		if strings.HasSuffix(arg, "=true") || strings.HasSuffix(arg, "=false") {
 			flag := strings.ToLower(strings.TrimLeft(arg, "-"))
 			flag = strings.TrimSuffix(flag, "=true")
diff --git a/resolver.go b/resolver.go
index 035e0a4..5952c08 100644
--- a/resolver.go
+++ b/resolver.go
@@ -137,6 +137,7 @@ func newTransport(server string, transportType transport.Type, tlsConfig *tls.Co
 				UserAgent: opts.HTTPUserAgent,
 				Method:    opts.HTTPMethod,
 				Timeout:   opts.Timeout,
+				HTTP2:     opts.HTTP2,
 				HTTP3:     opts.HTTP3,
 				NoPMTUd:   !opts.PMTUD,
 				ReuseConn: opts.ReuseConn,
diff --git a/transport/http.go b/transport/http.go
index ae1a22a..97d807f 100644
--- a/transport/http.go
+++ b/transport/http.go
@@ -13,18 +13,19 @@ import (
 	"github.com/quic-go/quic-go"
 	"github.com/quic-go/quic-go/http3"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/http2"
 )
 
 // HTTP makes a DNS query over HTTP(s)
 type HTTP struct {
-	Server    string
-	TLSConfig *tls.Config
-	UserAgent string
-	Method    string
-	Timeout   time.Duration
-	HTTP3     bool
-	NoPMTUd   bool
-	ReuseConn bool
+	Server       string
+	TLSConfig    *tls.Config
+	UserAgent    string
+	Method       string
+	Timeout      time.Duration
+	HTTP2, HTTP3 bool
+	NoPMTUd      bool
+	ReuseConn    bool
 
 	conn *http.Client
 }
@@ -40,6 +41,13 @@ func (h *HTTP) Exchange(m *dns.Msg) (*dns.Msg, error) {
 				Proxy:           http.ProxyFromEnvironment,
 			},
 		}
+		if h.HTTP2 {
+			log.Debug("Using HTTP/2")
+			h.conn.Transport = &http2.Transport{
+				TLSClientConfig: h.TLSConfig,
+				AllowHTTP:       true,
+			}
+		}
 		if h.HTTP3 {
 			log.Debug("Using HTTP/3")
 			h.conn.Transport = &http3.RoundTripper{