Link refactoring, admin socket changes

src/core/link_tcp.go

@@ -6,7 +6,6 @@ import (
 	"net"
 	"net/url"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/Arceliar/phony"
@@ -15,19 +14,19 @@ import (
 type linkTCP struct {
 	phony.Inbox
 	*links
-	listener   *net.ListenConfig
-	_listeners map[*Listener]context.CancelFunc
+	listenconfig *net.ListenConfig
+	_listeners   map[*Listener]context.CancelFunc
 }
 
 func (l *links) newLinkTCP() *linkTCP {
 	lt := &linkTCP{
 		links: l,
-		listener: &net.ListenConfig{
+		listenconfig: &net.ListenConfig{
 			KeepAlive: -1,
 		},
 		_listeners: map[*Listener]context.CancelFunc{},
 	}
-	lt.listener.Control = lt.tcpContext
+	lt.listenconfig.Control = lt.tcpContext
 	return lt
 }
 
@@ -37,7 +36,7 @@ type tcpDialer struct {
 	addr   *net.TCPAddr
 }
 
-func (l *linkTCP) dialersFor(url *url.URL, options linkOptions, sintf string) ([]*tcpDialer, error) {
+func (l *linkTCP) dialersFor(url *url.URL, info linkInfo) ([]*tcpDialer, error) {
 	host, p, err := net.SplitHostPort(url.Host)
 	if err != nil {
 		return nil, err
@@ -56,14 +55,10 @@ func (l *linkTCP) dialersFor(url *url.URL, options linkOptions, sintf string) ([
 			IP:   ip,
 			Port: port,
 		}
-		dialer, err := l.dialerFor(addr, sintf)
+		dialer, err := l.dialerFor(addr, info.sintf)
 		if err != nil {
 			continue
 		}
-		info := linkInfoFor("tcp", sintf, tcpIDFor(dialer.LocalAddr, addr))
-		if l.links.isConnectedTo(info) {
-			return nil, nil
-		}
 		dialers = append(dialers, &tcpDialer{
 			info:   info,
 			dialer: dialer,
@@ -73,13 +68,16 @@ func (l *linkTCP) dialersFor(url *url.URL, options linkOptions, sintf string) ([
 	return dialers, nil
 }
 
-func (l *linkTCP) dial(url *url.URL, options linkOptions, sintf string) error {
-	dialers, err := l.dialersFor(url, options, sintf)
+func (l *linkTCP) dial(url *url.URL, info linkInfo, options linkOptions) (net.Conn, error) {
+	if l.core.isTLSOnly() {
+		return nil, fmt.Errorf("TCP peer prohibited in TLS-only mode")
+	}
+	dialers, err := l.dialersFor(url, info)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	if len(dialers) == 0 {
-		return nil
+		return nil, nil
 	}
 	for _, d := range dialers {
 		var conn net.Conn
@@ -88,72 +86,22 @@ func (l *linkTCP) dial(url *url.URL, options linkOptions, sintf string) error {
 			l.core.log.Warnf("Failed to connect to %s: %s", d.addr, err)
 			continue
 		}
-		name := strings.TrimRight(strings.SplitN(url.String(), "?", 2)[0], "/")
-		dial := &linkDial{
-			url:   url,
-			sintf: sintf,
-		}
-		return l.handler(dial, name, d.info, conn, options, false, false)
+		return conn, nil
 	}
-	return fmt.Errorf("failed to connect via %d address(es), last error: %w", len(dialers), err)
+	return nil, err
 }
 
-func (l *linkTCP) listen(url *url.URL, sintf string) (*Listener, error) {
-	ctx, cancel := context.WithCancel(l.core.ctx)
+func (l *linkTCP) listen(ctx context.Context, url *url.URL, sintf string) (net.Listener, error) {
+	if l.core.isTLSOnly() {
+		return nil, fmt.Errorf("TCP listener prohibited in TLS-only mode")
+	}
 	hostport := url.Host
 	if sintf != "" {
 		if host, port, err := net.SplitHostPort(hostport); err == nil {
 			hostport = fmt.Sprintf("[%s%%%s]:%s", host, sintf, port)
 		}
 	}
-	listener, err := l.listener.Listen(ctx, "tcp", hostport)
-	if err != nil {
-		cancel()
-		return nil, err
-	}
-	entry := &Listener{
-		Listener: listener,
-		closed:   make(chan struct{}),
-	}
-	phony.Block(l, func() {
-		l._listeners[entry] = cancel
-	})
-	l.core.log.Printf("TCP listener started on %s", listener.Addr())
-	go func() {
-		defer phony.Block(l, func() {
-			delete(l._listeners, entry)
-		})
-		for {
-			conn, err := listener.Accept()
-			if err != nil {
-				cancel()
-				break
-			}
-			laddr := conn.LocalAddr().(*net.TCPAddr)
-			raddr := conn.RemoteAddr().(*net.TCPAddr)
-			name := fmt.Sprintf("tcp://%s", raddr)
-			info := linkInfoFor("tcp", sintf, tcpIDFor(laddr, raddr))
-			if err = l.handler(nil, name, info, conn, linkOptionsForListener(url), true, raddr.IP.IsLinkLocalUnicast()); err != nil {
-				l.core.log.Errorln("Failed to create inbound link:", err)
-			}
-		}
-		_ = listener.Close()
-		close(entry.closed)
-		l.core.log.Printf("TCP listener stopped on %s", listener.Addr())
-	}()
-	return entry, nil
-}
-
-func (l *linkTCP) handler(dial *linkDial, name string, info linkInfo, conn net.Conn, options linkOptions, incoming, force bool) error {
-	return l.links.create(
-		conn,     // connection
-		dial,     // connection URL
-		name,     // connection name
-		info,     // connection info
-		incoming, // not incoming
-		force,    // not forced
-		options,  // connection options
-	)
+	return l.listenconfig.Listen(ctx, "tcp", hostport)
 }
 
 // Returns the address of the listener.
@@ -163,8 +111,8 @@ func (l *linkTCP) getAddr() *net.TCPAddr {
 	// doesn't have the ability to send more than one address in a packet either
 	var addr *net.TCPAddr
 	phony.Block(l, func() {
-		for listener := range l._listeners {
-			addr = listener.Addr().(*net.TCPAddr)
+		for li := range l._listeners {
+			addr = li.listener.Addr().(*net.TCPAddr)
 		}
 	})
 	return addr
@@ -228,16 +176,3 @@ func (l *linkTCP) dialerFor(dst *net.TCPAddr, sintf string) (*net.Dialer, error)
 	}
 	return dialer, nil
 }
-
-func tcpIDFor(local net.Addr, remoteAddr *net.TCPAddr) string {
-	if localAddr, ok := local.(*net.TCPAddr); ok && localAddr.IP.Equal(remoteAddr.IP) {
-		// Nodes running on the same host — include both the IP and port.
-		return remoteAddr.String()
-	}
-	if remoteAddr.IP.IsLinkLocalUnicast() {
-		// Nodes discovered via multicast — include the IP only.
-		return remoteAddr.IP.String()
-	}
-	// Nodes connected remotely — include both the IP and port.
-	return remoteAddr.String()
-}