diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go index 72b2a45e5..cec9046a3 100644 --- a/p2p/discover/udp.go +++ b/p2p/discover/udp.go @@ -453,8 +453,11 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) ([]byte, return packet, nil } -type tempError interface { - Temporary() bool +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 diff --git a/p2p/discover/udp_notwindows.go b/p2p/discover/udp_notwindows.go new file mode 100644 index 000000000..e9de83aa9 --- /dev/null +++ b/p2p/discover/udp_notwindows.go @@ -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 . + +//+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 +} diff --git a/p2p/discover/udp_test.go b/p2p/discover/udp_test.go index 8ed12b8ec..ec28867cc 100644 --- a/p2p/discover/udp_test.go +++ b/p2p/discover/udp_test.go @@ -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 diff --git a/p2p/discover/udp_windows.go b/p2p/discover/udp_windows.go new file mode 100644 index 000000000..66bbf9597 --- /dev/null +++ b/p2p/discover/udp_windows.go @@ -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 . + +//+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 +}