platform: Add oom killer

common/dialer/conntrack/conn.go

@@ -1,29 +1,32 @@
 package conntrack
 
 import (
+	"io"
 	"net"
-	"runtime/debug"
 
 	"github.com/sagernet/sing/common/x/list"
 )
 
 type Conn struct {
 	net.Conn
-	element *list.Element[*ConnEntry]
+	element *list.Element[io.Closer]
 }
 
-func NewConn(conn net.Conn) *Conn {
-	entry := &ConnEntry{
-		Conn:  conn,
-		Stack: debug.Stack(),
-	}
+func NewConn(conn net.Conn) (*Conn, error) {
 	connAccess.Lock()
-	element := openConnection.PushBack(entry)
+	element := openConnection.PushBack(conn)
 	connAccess.Unlock()
+	if KillerEnabled {
+		err := killerCheck()
+		if err != nil {
+			conn.Close()
+			return nil, err
+		}
+	}
 	return &Conn{
 		Conn:    conn,
 		element: element,
-	}
+	}, nil
 }
 
 func (c *Conn) Close() error {

common/dialer/conntrack/killer.go

@@ -0,0 +1,38 @@
+package conntrack
+
+import (
+	"runtime"
+	runtimeDebug "runtime/debug"
+	"time"
+
+	E "github.com/sagernet/sing/common/exceptions"
+)
+
+var (
+	KillerEnabled   bool
+	MemoryLimit     int64
+	killerLastCheck time.Time
+)
+
+func killerCheck() error {
+	if !KillerEnabled {
+		return nil
+	}
+	nowTime := time.Now()
+	if nowTime.Sub(killerLastCheck) < 3*time.Second {
+		return nil
+	}
+	killerLastCheck = nowTime
+	var memStats runtime.MemStats
+	runtime.ReadMemStats(&memStats)
+	inuseMemory := int64(memStats.StackInuse + memStats.HeapInuse + memStats.HeapIdle - memStats.HeapReleased)
+	if inuseMemory > MemoryLimit {
+		Close()
+		go func() {
+			time.Sleep(time.Second)
+			runtimeDebug.FreeOSMemory()
+		}()
+		return E.New("out of memory")
+	}
+	return nil
+}

common/dialer/conntrack/packet_conn.go

@@ -1,29 +1,32 @@
 package conntrack
 
 import (
+	"io"
 	"net"
-	"runtime/debug"
 
 	"github.com/sagernet/sing/common/x/list"
 )
 
 type PacketConn struct {
 	net.PacketConn
-	element *list.Element[*ConnEntry]
+	element *list.Element[io.Closer]
 }
 
-func NewPacketConn(conn net.PacketConn) *PacketConn {
-	entry := &ConnEntry{
-		Conn:  conn,
-		Stack: debug.Stack(),
-	}
+func NewPacketConn(conn net.PacketConn) (*PacketConn, error) {
 	connAccess.Lock()
-	element := openConnection.PushBack(entry)
+	element := openConnection.PushBack(conn)
 	connAccess.Unlock()
+	if KillerEnabled {
+		err := killerCheck()
+		if err != nil {
+			conn.Close()
+			return nil, err
+		}
+	}
 	return &PacketConn{
 		PacketConn: conn,
 		element:    element,
-	}
+	}, nil
 }
 
 func (c *PacketConn) Close() error {

common/dialer/conntrack/track.go

@@ -10,22 +10,17 @@ import (
 
 var (
 	connAccess     sync.RWMutex
-	openConnection list.List[*ConnEntry]
+	openConnection list.List[io.Closer]
 )
 
-type ConnEntry struct {
-	Conn  io.Closer
-	Stack []byte
-}
-
 func Count() int {
 	return openConnection.Len()
 }
 
-func List() []*ConnEntry {
+func List() []io.Closer {
 	connAccess.RLock()
 	defer connAccess.RUnlock()
-	connList := make([]*ConnEntry, 0, openConnection.Len())
+	connList := make([]io.Closer, 0, openConnection.Len())
 	for element := openConnection.Front(); element != nil; element = element.Next() {
 		connList = append(connList, element.Value)
 	}
@@ -36,8 +31,8 @@ func Close() {
 	connAccess.Lock()
 	defer connAccess.Unlock()
 	for element := openConnection.Front(); element != nil; element = element.Next() {
-		common.Close(element.Value.Conn)
+		common.Close(element.Value)
 		element.Value = nil
 	}
-	openConnection = list.List[*ConnEntry]{}
+	openConnection.Init()
 }

common/dialer/default.go

@@ -178,12 +178,12 @@ func trackConn(conn net.Conn, err error) (net.Conn, error) {
 	if !conntrack.Enabled || err != nil {
 		return conn, err
 	}
-	return conntrack.NewConn(conn), nil
+	return conntrack.NewConn(conn)
 }
 
 func trackPacketConn(conn net.PacketConn, err error) (net.PacketConn, error) {
 	if !conntrack.Enabled || err != nil {
 		return conn, err
 	}
-	return conntrack.NewPacketConn(conn), nil
+	return conntrack.NewPacketConn(conn)
 }

experimental/libbox/memory.go

@@ -2,9 +2,17 @@
 
 package libbox
 
-import "runtime/debug"
+import (
+	runtimeDebug "runtime/debug"
+
+	"github.com/sagernet/sing-box/common/dialer/conntrack"
+)
+
+const memoryLimit = 30 * 1024 * 1024
 
 func SetMemoryLimit() {
-	debug.SetGCPercent(10)
-	debug.SetMemoryLimit(30 * 1024 * 1024)
+	runtimeDebug.SetGCPercent(10)
+	runtimeDebug.SetMemoryLimit(memoryLimit)
+	conntrack.KillerEnabled = true
+	conntrack.MemoryLimit = memoryLimit
 }