lib/connections: Add KCP support (fixes #804)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3489

lib/connections/util.go

@@ -0,0 +1,29 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package connections
+
+import (
+	"net"
+	"net/url"
+	"strconv"
+	"strings"
+)
+
+func fixupPort(uri *url.URL, defaultPort int) *url.URL {
+	copyURI := *uri
+
+	host, port, err := net.SplitHostPort(uri.Host)
+	if err != nil && strings.Contains(err.Error(), "missing port") {
+		// addr is on the form "1.2.3.4"
+		copyURI.Host = net.JoinHostPort(uri.Host, strconv.Itoa(defaultPort))
+	} else if err == nil && port == "" {
+		// addr is on the form "1.2.3.4:"
+		copyURI.Host = net.JoinHostPort(host, strconv.Itoa(defaultPort))
+	}
+
+	return &copyURI
+}