Improving Mac discovery

internal/clientinfo/arp_linux.go

@@ -0,0 +1,28 @@
+package clientinfo
+
+import (
+	"bufio"
+	"os"
+	"strings"
+)
+
+const procNetArpFile = "/proc/net/arp"
+
+func (a *arpDiscover) scan() {
+	f, err := os.Open(procNetArpFile)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	s := bufio.NewScanner(f)
+	s.Scan() // skip header
+	for s.Scan() {
+		line := s.Text()
+		fields := strings.Fields(line)
+		ip := fields[0]
+		mac := fields[3]
+		a.mac.Store(ip, mac)
+		a.ip.Store(mac, ip)
+	}
+}