Checkpoint

internal/netutil/arp/arp_linux.go

@@ -0,0 +1,32 @@
+package arp
+
+import (
+	"bufio"
+	"net"
+	"os"
+	"strings"
+)
+
+func lookup() (map[string]net.HardwareAddr, error) {
+	f, err := os.Open("/proc/net/arp")
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = f.Close() }()
+
+	t := make(map[string]net.HardwareAddr)
+	s := bufio.NewScanner(f)
+	for i := 0; s.Scan(); i++ {
+		if i == 0 {
+			continue
+		}
+		line := strings.Fields(s.Text())
+		if len(line) < 4 {
+			continue
+		}
+		if mac, err := net.ParseMAC(line[3]); err == nil {
+			t[line[0]] = mac
+		}
+	}
+	return t, nil
+}