wip: migrate to mono-repo. SPN has already been moved to spn/

service/network/state/system_linux.go

@@ -0,0 +1,40 @@
+package state
+
+import (
+	"time"
+
+	"github.com/safing/portmaster/service/network/proc"
+	"github.com/safing/portmaster/service/network/socket"
+)
+
+var (
+	getTCP4Table = proc.GetTCP4Table
+	getTCP6Table = proc.GetTCP6Table
+	getUDP4Table = proc.GetUDP4Table
+	getUDP6Table = proc.GetUDP6Table
+
+	checkPIDTries        = 5
+	checkPIDBaseWaitTime = 5 * time.Millisecond
+)
+
+// CheckPID checks the if socket info already has a PID and if not, tries to find it.
+// Depending on the OS, this might be a no-op.
+func CheckPID(socketInfo socket.Info, connInbound bool) (pid int, inbound bool, err error) {
+	for i := 1; i <= checkPIDTries; i++ {
+		// look for PID
+		pid = proc.GetPID(socketInfo)
+		if pid != socket.UndefinedProcessID {
+			// if we found a PID, return
+			break
+		}
+
+		// every time, except for the last iteration
+		if i < checkPIDTries {
+			// we found no PID, we could have been too fast, give the kernel some time to think
+			// back off timer: with 5ms baseWaitTime: 5, 10, 15, 20, 25 - 75ms in total
+			time.Sleep(time.Duration(i) * checkPIDBaseWaitTime)
+		}
+	}
+
+	return pid, connInbound, nil
+}