From e664a6aa1457beed6af80d912eeb0064573b28ac Mon Sep 17 00:00:00 2001
From: Yusef Napora <yusef@protocol.ai>
Date: Tue, 12 Nov 2019 11:16:37 -0500
Subject: [PATCH] use varints for delimiting plaintext 2.0 msgs

---
 sec/insecure/insecure.go | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/sec/insecure/insecure.go b/sec/insecure/insecure.go
index e3670c2..6a600a3 100644
--- a/sec/insecure/insecure.go
+++ b/sec/insecure/insecure.go
@@ -6,11 +6,13 @@ package insecure
 import (
 	"context"
 	"fmt"
+	"io"
 	"net"
 
+	gogoio "github.com/gogo/protobuf/io"
+
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/sec"
-	"github.com/libp2p/go-msgio"
 
 	ci "github.com/libp2p/go-libp2p-core/crypto"
 	pb "github.com/libp2p/go-libp2p-core/sec/insecure/pb"
@@ -143,7 +145,6 @@ func (ic *Conn) runHandshakeSync() error {
 		return nil
 	}
 
-	rw := msgio.NewReadWriter(ic.Conn)
 	// Generate an Exchange message
 	msg, err := makeExchangeMessage(ic.localPrivKey.GetPublic())
 	if err != nil {
@@ -151,7 +152,7 @@ func (ic *Conn) runHandshakeSync() error {
 	}
 
 	// Send our Exchange and read theirs
-	remoteMsg, err := readWriteMsg(rw, msg)
+	remoteMsg, err := readWriteMsg(ic.Conn, msg)
 	if err != nil {
 		return err
 	}
@@ -181,31 +182,28 @@ func (ic *Conn) runHandshakeSync() error {
 }
 
 // read and write a message at the same time.
-func readWriteMsg(c msgio.ReadWriter, out *pb.Exchange) (*pb.Exchange, error) {
-	outBytes, err := out.Marshal()
-	if err != nil {
-		return nil, err
-	}
+func readWriteMsg(rw io.ReadWriter, out *pb.Exchange) (*pb.Exchange, error) {
+	const maxMsgSize = 1 << 32
+	r := gogoio.NewDelimitedReader(rw, maxMsgSize)
+	w := gogoio.NewDelimitedWriter(rw)
 	wresult := make(chan error)
 	go func() {
-		wresult <- c.WriteMsg(outBytes)
+		wresult <- w.WriteMsg(out)
 	}()
 
-	msg, err1 := c.ReadMsg()
+	inMsg := pb.Exchange{}
+	err := r.ReadMsg(&inMsg)
 
 	// Always wait for the read to finish.
 	err2 := <-wresult
 
-	if err1 != nil {
-		return nil, err1
+	if err != nil {
+		return nil, err
 	}
 	if err2 != nil {
-		c.ReleaseMsg(msg)
 		return nil, err2
 	}
-	inMsg := new(pb.Exchange)
-	err = inMsg.Unmarshal(msg)
-	return inMsg, err
+	return &inMsg, err
 }
 
 // LocalPeer returns the local peer ID.