Merge pull request #2146 from fjl/discover-win32-large-packets

p2p/discover: fix Windows-specific issue for larger-than-buffer packets
This commit is contained in:
Jeffrey Wilcke 2016-02-01 11:36:31 +01:00
commit f85212aa86
4 changed files with 124 additions and 7 deletions

View File

@ -453,8 +453,11 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) ([]byte,
return packet, nil
}
type tempError interface {
func isTemporaryError(err error) bool {
tempErr, ok := err.(interface {
Temporary() bool
})
return ok && tempErr.Temporary() || isPacketTooBig(err)
}
// readLoop runs in its own goroutine. it handles incoming UDP packets.
@ -466,7 +469,7 @@ func (t *udp) readLoop() {
buf := make([]byte, 1280)
for {
nbytes, from, err := t.conn.ReadFromUDP(buf)
if tempErr, ok := err.(tempError); ok && tempErr.Temporary() {
if isTemporaryError(err) {
// Ignore temporary read errors.
glog.V(logger.Debug).Infof("Temporary read error: %v", err)
continue

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@ -0,0 +1,26 @@
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//+build !windows
package discover
// reports whether err indicates that a UDP packet didn't
// fit the receive buffer. There is no such error on
// non-Windows platforms.
func isPacketTooBig(err error) bool {
return false
}

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@ -23,10 +23,8 @@ import (
"errors"
"fmt"
"io"
logpkg "log"
"math/rand"
"net"
"os"
"path/filepath"
"reflect"
"runtime"
@ -34,12 +32,62 @@ import (
"testing"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
)
func init() {
logger.AddLogSystem(logger.NewStdLogSystem(os.Stdout, logpkg.LstdFlags, logger.ErrorLevel))
spew.Config.DisableMethods = true
}
// This test checks that isPacketTooBig correctly identifies
// errors that result from receiving a UDP packet larger
// than the supplied receive buffer.
func TestIsPacketTooBig(t *testing.T) {
listener, err := net.ListenPacket("udp", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
defer listener.Close()
sender, err := net.Dial("udp", listener.LocalAddr().String())
if err != nil {
t.Fatal(err)
}
defer sender.Close()
sendN := 1800
recvN := 300
for i := 0; i < 20; i++ {
go func() {
buf := make([]byte, sendN)
for i := range buf {
buf[i] = byte(i)
}
sender.Write(buf)
}()
buf := make([]byte, recvN)
listener.SetDeadline(time.Now().Add(1 * time.Second))
n, _, err := listener.ReadFrom(buf)
if err != nil {
if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
continue
}
if !isPacketTooBig(err) {
t.Fatal("unexpected read error:", spew.Sdump(err))
}
continue
}
if n != recvN {
t.Fatalf("short read: %d, want %d", n, recvN)
}
for i := range buf {
if buf[i] != byte(i) {
t.Fatalf("error in pattern")
break
}
}
}
}
// shared test variables

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@ -0,0 +1,40 @@
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//+build windows
package discover
import (
"net"
"os"
"syscall"
)
const _WSAEMSGSIZE = syscall.Errno(10040)
// reports whether err indicates that a UDP packet didn't
// fit the receive buffer. On Windows, WSARecvFrom returns
// code WSAEMSGSIZE and no data if this happens.
func isPacketTooBig(err error) bool {
if opErr, ok := err.(*net.OpError); ok {
if scErr, ok := opErr.Err.(*os.SyscallError); ok {
return scErr.Err == _WSAEMSGSIZE
}
return opErr.Err == _WSAEMSGSIZE
}
return false
}