platform: Add oom killer

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
+}