monitor:overlay: fix cache with old eth state

Similar as in the previous commit, while printing connection info, the info
concerning the eth layer are retrieved from the cache and not the
connection structure previously created. This means that we must be aware
whether referring `cache.eth` or `cache.overlay.eth`.
This commits adjusts this. Let's test this by first decodin an ACK native
packet (also when L3 packet), then a SYN VXLAN, then an ACK GENEVE, and
finally a native SYN.

Signed-off-by: Simone Magnani <simone.magnani@isovalent.com>

Author: smagnani96

pkg/monitor/dissect.go

@@ -135,6 +135,15 @@ func getTCPInfo(isOverlay bool) string {
 	return info
 }
 
+func getEthInfo(isOverlay bool) string {
+	target := cache.eth
+	if isOverlay {
+		target = cache.overlay.eth
+	}
+
+	return fmt.Sprintf("%s -> %s %s", target.SrcMAC, target.DstMAC, target.EthernetType.String())
+}
+
 // ConnectionInfo contains tuple information and icmp code for a connection
 type ConnectionInfo struct {
 	SrcIP    net.IP
@@ -309,7 +318,7 @@ func GetConnectionSummary(data []byte, opts *decodeOpts) string {
 	case hasIP:
 		str += fmt.Sprintf("%s -> %s", c.SrcIP, c.DstIP)
 	case hasEth:
-		str += fmt.Sprintf("%s -> %s %s", cache.eth.SrcMAC, cache.eth.DstMAC, cache.eth.EthernetType.String())
+		str += getEthInfo(c.isOverlay())
 	default:
 		str += "[unknown]"
 	}

pkg/monitor/dissect_test.go

@@ -55,8 +55,8 @@ func TestConnectionSummaryTcp(t *testing.T) {
 		IsL3Device bool
 	}{{"L3Device", true}, {"L2Device", false}} {
 		t.Run(c.Name, func(t *testing.T) {
-			// Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443)
-			data := []byte{2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 2, 32, 0, 125, 196, 0, 0}
+			// Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443,flags="A")
+			data := []byte{2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 16, 32, 0, 125, 182, 0, 0}
 			if c.IsL3Device {
 				// Remove ethernet layer.
 				data = data[14:]
@@ -66,7 +66,7 @@ func TestConnectionSummaryTcp(t *testing.T) {
 			expect := fmt.Sprintf("%s -> %s %s",
 				net.JoinHostPort(srcIP, sport),
 				net.JoinHostPort(dstIP, dport),
-				"tcp SYN")
+				"tcp ACK")
 			require.Equal(t, expect, summary)
 		})
 	}
@@ -79,27 +79,40 @@ func TestConnectionSummaryTcp(t *testing.T) {
 
 	for _, c := range []struct {
 		Name string
+		Flag string
 		Data []byte
 	}{
-		// Ether(src="01:02:03:04:05:06", dst="11:12:13:14:15:16")/IP(src="1.1.1.1",dst="2.2.2.2")/UDP(sport=8472,dport=9999)/VXLAN(vni=2)/Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443)
-		{"VXLAN", []byte{17, 18, 19, 20, 21, 22, 1, 2, 3, 4, 5, 6, 8, 0, 69, 0, 0, 90, 0, 1, 0, 0, 64, 17, 116, 141, 1, 1, 1, 1, 2, 2, 2, 2, 33, 24, 39, 15, 0, 70, 9, 229, 12, 0, 0, 3, 0, 0, 2, 0, 2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 2, 32, 0, 125, 196, 0, 0}},
-		// Ether(src="01:02:03:04:05:06", dst="11:12:13:14:15:16")/IP(src="1.1.1.1",dst="2.2.2.2")/UDP(sport=8472,dport=9999)/GENEVE(vni=2,proto=0x6558)/Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443)
-		{"Geneve", []byte{17, 18, 19, 20, 21, 22, 1, 2, 3, 4, 5, 6, 8, 0, 69, 0, 0, 90, 0, 1, 0, 0, 64, 17, 116, 141, 1, 1, 1, 1, 2, 2, 2, 2, 33, 24, 39, 15, 0, 70, 176, 143, 0, 0, 101, 88, 0, 0, 2, 0, 2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 2, 32, 0, 125, 196, 0, 0}},
+		// Ether(src="01:02:03:04:05:06", dst="11:12:13:14:15:16")/IP(src="1.1.1.1",dst="2.2.2.2")/UDP(sport=8472,dport=9999)/VXLAN(vni=2)/Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443,flags="S")
+		{"VXLAN", "SYN", []byte{17, 18, 19, 20, 21, 22, 1, 2, 3, 4, 5, 6, 8, 0, 69, 0, 0, 90, 0, 1, 0, 0, 64, 17, 116, 141, 1, 1, 1, 1, 2, 2, 2, 2, 33, 24, 39, 15, 0, 70, 9, 229, 12, 0, 0, 3, 0, 0, 2, 0, 2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 2, 32, 0, 125, 196, 0, 0}},
+		// Ether(src="01:02:03:04:05:06", dst="11:12:13:14:15:16")/IP(src="1.1.1.1",dst="2.2.2.2")/UDP(sport=8472,dport=9999)/GENEVE(vni=2,proto=0x6558)/Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443,flags="A")
+		{"Geneve", "ACK", []byte{17, 18, 19, 20, 21, 22, 1, 2, 3, 4, 5, 6, 8, 0, 69, 0, 0, 90, 0, 1, 0, 0, 64, 17, 116, 141, 1, 1, 1, 1, 2, 2, 2, 2, 33, 24, 39, 15, 0, 70, 176, 143, 0, 0, 101, 88, 0, 0, 2, 0, 2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 16, 32, 0, 125, 182, 0, 0}},
 	} {
 		t.Run(c.Name, func(t *testing.T) {
 			summary := GetConnectionSummary(c.Data, &decodeOpts{IsVXLAN: c.Name == "VXLAN", IsGeneve: c.Name == "Geneve"})
 
 			expect := fmt.Sprintf("%s -> %s %s [tunnel %s -> %s %s]",
 				net.JoinHostPort(srcIP, sport),
 				net.JoinHostPort(dstIP, dport),
-				"tcp SYN",
+				"tcp "+c.Flag,
 				net.JoinHostPort(srcIPOuter, sportOuter),
 				net.JoinHostPort(dstIPOuter, dportOuter),
 				strings.ToLower(c.Name))
 
 			require.Equal(t, expect, summary)
 		})
 	}
+
+	t.Run("PostOverlay", func(t *testing.T) {
+		// Ether(src="01:23:45:67:89:ab", dst="02:33:45:67:89:ab")/IP(src="1.2.3.4",dst="5.6.7.8")/TCP(sport=80,dport=443,flags="S")
+		data := []byte{2, 51, 69, 103, 137, 171, 1, 35, 69, 103, 137, 171, 8, 0, 69, 0, 0, 40, 0, 1, 0, 0, 64, 6, 106, 188, 1, 2, 3, 4, 5, 6, 7, 8, 0, 80, 1, 187, 0, 0, 0, 0, 0, 0, 0, 0, 80, 2, 32, 0, 125, 196, 0, 0}
+		summary := GetConnectionSummary(data, nil)
+
+		expect := fmt.Sprintf("%s -> %s %s",
+			net.JoinHostPort(srcIP, sport),
+			net.JoinHostPort(dstIP, dport),
+			"tcp SYN")
+		require.Equal(t, expect, summary)
+	})
 }
 
 func TestConnectionSummaryIcmp(t *testing.T) {