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

p2p/discover: fix Windows-specific issue for larger-than-buffer packets

1 files changed, 40 insertions, 0 deletions

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 <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
+}