Provide a better table sorter for the conversations view

Prior to this change, the address columns were sorted as string. This
meant that, for example, 108.177.111.188 would appear in order before
13.225.190.211. This change makes use of better IPCompare and MACCompare
structs to provide the sorting logic in the conversations UI.

ui/convsui.go

@@ -61,6 +61,14 @@ const (
 	From Direction = iota
 )
 
+type ConvAddr int
+
+const (
+	IPv4Addr ConvAddr = 0
+	IPv6Addr ConvAddr = iota
+	MacAddr  ConvAddr = iota
+)
+
 type FilterMask int
 
 const (
@@ -833,6 +841,11 @@ func (w *ConvsUiWidget) OnData(data string, app gowid.IApp) {
 			ports = termshark.StringInSlice(cur, []string{"UDP", "TCP"})
 			ipv6 := (cur == "IPv6")
 
+			var addrComp table.ICompare = termshark.IPCompare{}
+			if termshark.StringInSlice(cur, []string{"Ethernet"}) {
+				addrComp = termshark.MACCompare{}
+			}
+
 			if ports {
 				hdrs = []string{
 					"Addr A",
@@ -863,9 +876,9 @@ func (w *ConvsUiWidget) OnData(data string, app gowid.IApp) {
 					weightupto(200, 8),  // durn
 				}
 				comps = []table.ICompare{
-					table.StringCompare{},
+					addrComp,
 					table.IntCompare{},
-					table.StringCompare{},
+					addrComp,
 					table.IntCompare{},
 					table.IntCompare{},
 					table.IntCompare{},
@@ -908,8 +921,8 @@ func (w *ConvsUiWidget) OnData(data string, app gowid.IApp) {
 					wids[1] = weightupto(500, 42)
 				}
 				comps = []table.ICompare{
-					table.StringCompare{},
-					table.StringCompare{},
+					addrComp,
+					addrComp,
 					table.IntCompare{},
 					table.IntCompare{},
 					table.IntCompare{},

utils.go

@@ -841,6 +841,36 @@ var _ table.ICompare = IPCompare{}
 
 //======================================================================
 
+// MacCompare is a unit type that satisfies ICompare, and can be used
+// for numerically comparing MAC addresses.
+type MACCompare struct{}
+
+func (s MACCompare) Less(i, j string) bool {
+	x, errx := net.ParseMAC(i)
+	y, erry := net.ParseMAC(j)
+	if errx == nil && erry == nil {
+		for i := 0; i < len(x); i++ {
+			switch {
+			case x[i] < y[i]:
+				return true
+			case y[i] < x[i]:
+				return false
+			}
+		}
+		return false
+	} else if errx == nil {
+		return true
+	} else if erry == nil {
+		return false
+	} else {
+		return i < j
+	}
+}
+
+var _ table.ICompare = MACCompare{}
+
+//======================================================================
+
 func PrunePcapCache() error {
 	// This is a new option. Best to err on the side of caution and, if not, present
 	// assume the cache can grow indefinitely - in case users are now relying on this

utils_test.go

@@ -164,6 +164,16 @@ func TestIPComp1(t *testing.T) {
 	assert.False(t, ip.Less("2001:db8::68", "192.168.0.253"))
 }
 
+func TestMACComp1(t *testing.T) {
+	var mac MACCompare
+	assert.True(t, mac.Less("x", "y"))
+	assert.True(t, mac.Less("11:22:33:44:55:66", "y"))
+	assert.True(t, mac.Less("xx:22:33:44:55:66", "y"))
+	assert.False(t, mac.Less("xx:22:33:44:55:66", "11:22:33:44:55:66"))
+	assert.True(t, mac.Less("11:22:33:44:55:66", "11:22:33:44:55:67"))
+	assert.False(t, mac.Less("11:22:33:44:55:66", "11:22:33:44:54:66"))
+}
+
 func TestFolders(t *testing.T) {
 	tmp := os.Getenv("TMPDIR")
 	os.Setenv("TMPDIR", "/foo")