Allow not to limit bandwidth in LAN (fixes #1336)

internal/osutil/lan_unix.go

@@ -0,0 +1,39 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This program is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// This program 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 General Public License for
+// more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !windows
+
+package osutil
+
+import (
+	"net"
+)
+
+func GetLans() ([]*net.IPNet, error) {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return nil, err
+	}
+
+	nets := make([]*net.IPNet, 0, len(addrs))
+
+	for _, addr := range addrs {
+		net, ok := addr.(*net.IPNet)
+		if ok {
+			nets = append(nets, net)
+		}
+	}
+	return nets, nil
+}