Windows net tap implementation

nettap/alloc.go

@@ -0,0 +1,77 @@
+package nettap
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	"github.com/shirou/gopsutil/process"
+)
+
+type NetTapAlloc struct {
+	TapName string
+	PID     int
+}
+
+func (a *NetTapAlloc) Validate() error {
+	err := ValidateTapName(a.TapName)
+	if err != nil {
+		return errors.Wrap(err, "validate tap name")
+	}
+
+	if a.PID == 0 {
+		return fmt.Errorf("pid is zero")
+	}
+
+	if a.PID > int(a.PID) {
+		return fmt.Errorf("pid int32 overflow (%v)", a.PID)
+	}
+
+	return nil
+}
+
+// The taps removed slice always returns the taps removed, even after
+// an error has occurred sometime while deleting non-first interfaces.
+func (tm *TapManager) PruneTaps(knownAllocs []NetTapAlloc) ([]string, error) {
+	var tapsRemoved []string
+
+	for i, alloc := range knownAllocs {
+		err := alloc.Validate()
+		if err != nil {
+			return tapsRemoved, errors.Wrapf(err, "validate alloc #%v", i)
+		}
+	}
+
+	runningPids, err := process.Pids()
+	if err != nil {
+		return tapsRemoved, errors.Wrap(err, "get running pids")
+	}
+
+	runningPidsMap := make(map[int32]struct{})
+	for _, pid := range runningPids {
+		runningPidsMap[pid] = struct{}{}
+	}
+
+	var tapsToRemove []string
+
+	for _, alloc := range knownAllocs {
+		if _, exists := runningPidsMap[int32(alloc.PID)]; !exists {
+			tm.logger.Info("Found a dangling network tap", "name", alloc.TapName, "pid", alloc.PID)
+			tapsToRemove = append(tapsToRemove, alloc.TapName)
+		}
+	}
+
+	for _, tapToRemove := range tapsToRemove {
+		err = tm.DeleteTap(tapToRemove)
+		if err != nil {
+			if errors.Is(err, ErrTapNotFound) {
+				tm.logger.Warn("Attempted to prune a network tap that doesn't exist, skipping", "name", tapToRemove)
+			} else {
+				return tapsRemoved, errors.Wrapf(err, "delete tap '%v'", tapToRemove)
+			}
+		}
+
+		tapsRemoved = append(tapsRemoved, tapToRemove)
+	}
+
+	return tapsRemoved, nil
+}