fix: udp handling and ipv4 and ipv6 filtering

cmd/stats.go

@@ -44,6 +44,10 @@ var (
 	statsInterval     time.Duration
 	statsCount        int
 	statsNoHeaders    bool
+	statsTCP          bool
+	statsUDP          bool
+	statsListen       bool
+	statsEstab        bool
 )
 
 var statsCmd = &cobra.Command{
@@ -70,6 +74,18 @@ func runStatsCommand(args []string) {
 	filters.IPv4 = ipv4
 	filters.IPv6 = ipv6
 
+	// apply shortcut flags
+	if statsTCP && !statsUDP {
+		filters.Proto = "tcp"
+	} else if statsUDP && !statsTCP {
+		filters.Proto = "udp"
+	}
+	if statsListen && !statsEstab {
+		filters.State = "LISTEN"
+	} else if statsEstab && !statsListen {
+		filters.State = "ESTABLISHED"
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -297,4 +313,10 @@ func init() {
 	statsCmd.Flags().BoolVar(&statsNoHeaders, "no-headers", false, "Omit headers for table/csv output")
 	statsCmd.Flags().BoolVarP(&ipv4, "ipv4", "4", false, "Only show IPv4 connections")
 	statsCmd.Flags().BoolVarP(&ipv6, "ipv6", "6", false, "Only show IPv6 connections")
+
+	// shortcut filters
+	statsCmd.Flags().BoolVarP(&statsTCP, "tcp", "t", false, "Show only TCP connections")
+	statsCmd.Flags().BoolVarP(&statsUDP, "udp", "u", false, "Show only UDP connections")
+	statsCmd.Flags().BoolVarP(&statsListen, "listen", "l", false, "Show only listening sockets")
+	statsCmd.Flags().BoolVarP(&statsEstab, "established", "e", false, "Show only established connections")
 }

cmd/testdata/golden/mixed_protocols_json.golden

@@ -28,7 +28,7 @@
     "uid": 0,
     "proto": "udp",
     "ipversion": "",
-    "state": "CONNECTED",
+    "state": "LISTEN",
     "laddr": "0.0.0.0",
     "lport": 53,
     "raddr": "",

cmd/testdata/golden/mixed_protocols_table.golden

@@ -1,4 +1,4 @@
 PID   PROCESS      USER   PROTO           STATE                LADDR            LPORT    RADDR   RPORT
 1            tcp-server          tcp    LISTEN      0.0.0.0          http             0
-2            udp-server          udp    CONNECTED   0.0.0.0          domain           0
+2            udp-server          udp    LISTEN      0.0.0.0          domain           0
 3            unix-app            unix   CONNECTED   /tmp/test.sock   0                0

cmd/testdata/golden/udp_filter_json.golden

@@ -7,7 +7,7 @@
     "uid": 0,
     "proto": "udp",
     "ipversion": "",
-    "state": "CONNECTED",
+    "state": "LISTEN",
     "laddr": "0.0.0.0",
     "lport": 53,
     "raddr": "",