From 4525269cd830ac2ba338d9e1281ea80d66e189cf Mon Sep 17 00:00:00 2001
From: Juan Batiz-Benet <juan@benet.ai>
Date: Sun, 11 Jan 2015 11:59:25 -0800
Subject: [PATCH] p2p/net/conn/listener: ignore certain errors

This should handle early breakages, where a failing connection
would take out the listener entirely.

There are probably other errors we should be handling here,
like secure connection failures.
---
 p2p/net/conn/dial_test.go | 91 +++++++++++++++++++++++++++++++++++++++
 p2p/net/conn/listen.go    | 61 +++++++++++++++++++-------
 2 files changed, 136 insertions(+), 16 deletions(-)

diff --git a/p2p/net/conn/dial_test.go b/p2p/net/conn/dial_test.go
index b757a1b69..3c141012c 100644
--- a/p2p/net/conn/dial_test.go
+++ b/p2p/net/conn/dial_test.go
@@ -1,8 +1,10 @@
 package conn
 
 import (
+	"fmt"
 	"io"
 	"net"
+	"strings"
 	"testing"
 	"time"
 
@@ -103,6 +105,9 @@ func testDialer(t *testing.T, secure bool) {
 	if !secure {
 		key1 = nil
 		key2 = nil
+		t.Log("testing insecurely")
+	} else {
+		t.Log("testing securely")
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -164,3 +169,89 @@ func TestDialerSecure(t *testing.T) {
 	// t.Skip("Skipping in favor of another test")
 	testDialer(t, true)
 }
+
+func testDialerCloseEarly(t *testing.T, secure bool) {
+	// t.Skip("Skipping in favor of another test")
+
+	p1 := tu.RandPeerNetParamsOrFatal(t)
+	p2 := tu.RandPeerNetParamsOrFatal(t)
+
+	key1 := p1.PrivKey
+	if !secure {
+		key1 = nil
+		t.Log("testing insecurely")
+	} else {
+		t.Log("testing securely")
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	l1, err := Listen(ctx, p1.Addr, p1.ID, key1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	p1.Addr = l1.Multiaddr() // Addr has been determined by kernel.
+
+	// lol nesting
+	d2 := &Dialer{
+		LocalPeer: p2.ID,
+		// PrivateKey: key2, -- dont give it key. we'll just close the conn.
+	}
+
+	errs := make(chan error, 100)
+	done := make(chan struct{}, 1)
+	gotclosed := make(chan struct{}, 1)
+	go func() {
+		defer func() { done <- struct{}{} }()
+
+		_, err := l1.Accept()
+		if err != nil {
+			if strings.Contains(err.Error(), "closed") {
+				gotclosed <- struct{}{}
+				return
+			}
+			errs <- err
+		}
+		errs <- fmt.Errorf("got conn")
+	}()
+
+	c, err := d2.Dial(ctx, p1.Addr, p1.ID)
+	if err != nil {
+		errs <- err
+	}
+	c.Close() // close it early.
+
+	readerrs := func() {
+		for {
+			select {
+			case e := <-errs:
+				t.Error(e)
+			default:
+				return
+			}
+		}
+	}
+	readerrs()
+
+	l1.Close()
+	<-done
+	cancel()
+	readerrs()
+	close(errs)
+
+	select {
+	case <-gotclosed:
+	default:
+		t.Error("did not get closed")
+	}
+}
+
+// we dont do a handshake with singleConn, so cant "close early."
+// func TestDialerCloseEarlyInsecure(t *testing.T) {
+// 	// t.Skip("Skipping in favor of another test")
+// 	testDialerCloseEarly(t, false)
+// }
+
+func TestDialerCloseEarlySecure(t *testing.T) {
+	// t.Skip("Skipping in favor of another test")
+	testDialerCloseEarly(t, true)
+}
diff --git a/p2p/net/conn/listen.go b/p2p/net/conn/listen.go
index 0cc1a75c8..c2049eacc 100644
--- a/p2p/net/conn/listen.go
+++ b/p2p/net/conn/listen.go
@@ -2,13 +2,14 @@ package conn
 
 import (
 	"fmt"
+	"io"
 	"net"
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
 	ctxgroup "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-ctxgroup"
 	ma "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr"
 	manet "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr-net"
-
+	tec "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-temp-err-catcher"
 	ic "github.com/jbenet/go-ipfs/p2p/crypto"
 	peer "github.com/jbenet/go-ipfs/p2p/peer"
 )
@@ -46,25 +47,53 @@ func (l *listener) Accept() (net.Conn, error) {
 	// Contexts and io don't mix.
 	ctx := context.Background()
 
-	maconn, err := l.Listener.Accept()
-	if err != nil {
-		return nil, err
+	var catcher tec.TempErrCatcher
+
+	catcher.IsTemp = func(e error) bool {
+		// ignore connection breakages up to this point. but log them
+		if e == io.EOF {
+			log.Debugf("listener ignoring conn with EOF: %s", e)
+			return true
+		}
+
+		te, ok := e.(tec.Temporary)
+		if ok {
+			log.Debugf("listener ignoring conn with temporary err: %s", e)
+			return te.Temporary()
+		}
+		return false
 	}
 
-	c, err := newSingleConn(ctx, l.local, "", maconn)
-	if err != nil {
-		return nil, fmt.Errorf("Error accepting connection: %v", err)
-	}
+	for {
+		maconn, err := l.Listener.Accept()
+		if err != nil {
+			if catcher.IsTemporary(err) {
+				continue
+			}
+			return nil, err
+		}
 
-	if l.privk == nil {
-		log.Warning("listener %s listening INSECURELY!", l)
-		return c, nil
+		c, err := newSingleConn(ctx, l.local, "", maconn)
+		if err != nil {
+			if catcher.IsTemporary(err) {
+				continue
+			}
+			return nil, err
+		}
+
+		if l.privk == nil {
+			log.Warning("listener %s listening INSECURELY!", l)
+			return c, nil
+		}
+		sc, err := newSecureConn(ctx, l.privk, c)
+		if err != nil {
+			if catcher.IsTemporary(err) {
+				continue
+			}
+			return nil, err
+		}
+		return sc, nil
 	}
-	sc, err := newSecureConn(ctx, l.privk, c)
-	if err != nil {
-		return nil, fmt.Errorf("Error securing connection: %v", err)
-	}
-	return sc, nil
 }
 
 func (l *listener) Addr() net.Addr {