Large refactoring/feature commit

1. Change listen addresses to URIs
2. Break out connectionSvc to support listeners and dialers based on schema
3. Add relay announcement and lookups part of discovery service

cmd/syncthing/connections_tcp.go

@@ -0,0 +1,95 @@
+// Copyright (C) 2015 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 main
+
+import (
+	"crypto/tls"
+	"net"
+	"net/url"
+	"strings"
+)
+
+func init() {
+	dialers["tcp"] = tcpDialer
+	listeners["tcp"] = tcpListener
+}
+
+func tcpDialer(uri *url.URL, tlsCfg *tls.Config) (*tls.Conn, error) {
+	host, port, err := net.SplitHostPort(uri.Host)
+	if err != nil && strings.HasPrefix(err.Error(), "missing port") {
+		// addr is on the form "1.2.3.4"
+		uri.Host = net.JoinHostPort(uri.Host, "22000")
+	} else if err == nil && port == "" {
+		// addr is on the form "1.2.3.4:"
+		uri.Host = net.JoinHostPort(host, "22000")
+	}
+
+	raddr, err := net.ResolveTCPAddr("tcp", uri.Host)
+	if err != nil {
+		if debugNet {
+			l.Debugln(err)
+		}
+		return nil, err
+	}
+
+	conn, err := net.DialTCP("tcp", nil, raddr)
+	if err != nil {
+		if debugNet {
+			l.Debugln(err)
+		}
+		return nil, err
+	}
+
+	setTCPOptions(conn)
+
+	tc := tls.Client(conn, tlsCfg)
+	err = tc.Handshake()
+	if err != nil {
+		tc.Close()
+		return nil, err
+	}
+
+	return tc, nil
+}
+
+func tcpListener(uri *url.URL, tlsCfg *tls.Config, conns chan<- *tls.Conn) {
+	tcaddr, err := net.ResolveTCPAddr("tcp", uri.Host)
+	if err != nil {
+		l.Fatalln("listen (BEP/tcp):", err)
+		return
+	}
+	listener, err := net.ListenTCP("tcp", tcaddr)
+	if err != nil {
+		l.Fatalln("listen (BEP/tcp):", err)
+		return
+	}
+
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			l.Warnln("Accepting connection (BEP/tcp):", err)
+			continue
+		}
+
+		if debugNet {
+			l.Debugln("connect from", conn.RemoteAddr())
+		}
+
+		tcpConn := conn.(*net.TCPConn)
+		setTCPOptions(tcpConn)
+
+		tc := tls.Server(conn, tlsCfg)
+		err = tc.Handshake()
+		if err != nil {
+			l.Infoln("TLS handshake (BEP/tcp):", err)
+			tc.Close()
+			continue
+		}
+
+		conns <- tc
+	}
+}