Add interrupt support for outbound groups

common/interrupt/conn.go

@@ -0,0 +1,75 @@
+package interrupt
+
+import (
+	"net"
+
+	"github.com/sagernet/sing/common/x/list"
+)
+
+/*type GroupedConn interface {
+	MarkAsInternal()
+}
+
+func MarkAsInternal(conn any) {
+	if groupedConn, isGroupConn := common.Cast[GroupedConn](conn); isGroupConn {
+		groupedConn.MarkAsInternal()
+	}
+}*/
+
+type Conn struct {
+	net.Conn
+	group   *Group
+	element *list.Element[*groupConnItem]
+}
+
+/*func (c *Conn) MarkAsInternal() {
+	c.element.Value.internal = true
+}*/
+
+func (c *Conn) Close() error {
+	c.group.access.Lock()
+	defer c.group.access.Unlock()
+	c.group.connections.Remove(c.element)
+	return c.Conn.Close()
+}
+
+func (c *Conn) ReaderReplaceable() bool {
+	return true
+}
+
+func (c *Conn) WriterReplaceable() bool {
+	return true
+}
+
+func (c *Conn) Upstream() any {
+	return c.Conn
+}
+
+type PacketConn struct {
+	net.PacketConn
+	group   *Group
+	element *list.Element[*groupConnItem]
+}
+
+/*func (c *PacketConn) MarkAsInternal() {
+	c.element.Value.internal = true
+}*/
+
+func (c *PacketConn) Close() error {
+	c.group.access.Lock()
+	defer c.group.access.Unlock()
+	c.group.connections.Remove(c.element)
+	return c.PacketConn.Close()
+}
+
+func (c *PacketConn) ReaderReplaceable() bool {
+	return true
+}
+
+func (c *PacketConn) WriterReplaceable() bool {
+	return true
+}
+
+func (c *PacketConn) Upstream() any {
+	return c.PacketConn
+}

common/interrupt/context.go

@@ -0,0 +1,13 @@
+package interrupt
+
+import "context"
+
+type contextKeyIsExternalConnection struct{}
+
+func ContextWithIsExternalConnection(ctx context.Context) context.Context {
+	return context.WithValue(ctx, contextKeyIsExternalConnection{}, true)
+}
+
+func IsExternalConnectionFromContext(ctx context.Context) bool {
+	return ctx.Value(contextKeyIsExternalConnection{}) != nil
+}

common/interrupt/group.go

@@ -0,0 +1,52 @@
+package interrupt
+
+import (
+	"io"
+	"net"
+	"sync"
+
+	"github.com/sagernet/sing/common/x/list"
+)
+
+type Group struct {
+	access      sync.Mutex
+	connections list.List[*groupConnItem]
+}
+
+type groupConnItem struct {
+	conn       io.Closer
+	isExternal bool
+}
+
+func NewGroup() *Group {
+	return &Group{}
+}
+
+func (g *Group) NewConn(conn net.Conn, isExternal bool) net.Conn {
+	g.access.Lock()
+	defer g.access.Unlock()
+	item := g.connections.PushBack(&groupConnItem{conn, isExternal})
+	return &Conn{Conn: conn, group: g, element: item}
+}
+
+func (g *Group) NewPacketConn(conn net.PacketConn, isExternal bool) net.PacketConn {
+	g.access.Lock()
+	defer g.access.Unlock()
+	item := g.connections.PushBack(&groupConnItem{conn, isExternal})
+	return &PacketConn{PacketConn: conn, group: g, element: item}
+}
+
+func (g *Group) Interrupt(interruptExternalConnections bool) {
+	g.access.Lock()
+	defer g.access.Unlock()
+	var toDelete []*list.Element[*groupConnItem]
+	for element := g.connections.Front(); element != nil; element = element.Next() {
+		if !element.Value.isExternal || interruptExternalConnections {
+			element.Value.conn.Close()
+			toDelete = append(toDelete, element)
+		}
+	}
+	for _, element := range toDelete {
+		g.connections.Remove(element)
+	}
+}