Fix skipped line with empty target in iptables (#3235)

(cherry picked from commit d5f48e3e96)

plugins/inputs/iptables/iptables.go

@@ -95,7 +95,7 @@ const measurement = "iptables"
 var errParse = errors.New("Cannot parse iptables list information")
 var chainNameRe = regexp.MustCompile(`^Chain\s+(\S+)`)
 var fieldsHeaderRe = regexp.MustCompile(`^\s*pkts\s+bytes\s+`)
-var commentRe = regexp.MustCompile(`\s*/\*\s*(.+?)\s*\*/\s*`)
+var valuesRe = regexp.MustCompile(`^\s*(\d+)\s+(\d+)\s+.*?/\*\s*(.+?)\s*\*/\s*`)
 
 func (ipt *Iptables) parseAndGather(data string, acc telegraf.Accumulator) error {
 	lines := strings.Split(data, "\n")
@@ -110,21 +110,14 @@ func (ipt *Iptables) parseAndGather(data string, acc telegraf.Accumulator) error
 		return errParse
 	}
 	for _, line := range lines[2:] {
-		tokens := strings.Fields(line)
-		if len(tokens) < 10 {
+		matches := valuesRe.FindStringSubmatch(line)
+		if len(matches) != 4 {
 			continue
 		}
 
-		pkts := tokens[0]
-		bytes := tokens[1]
-		end := strings.Join(tokens[9:], " ")
-
-		matches := commentRe.FindStringSubmatch(end)
-		if matches == nil {
-			continue
-		}
-
-		comment := matches[1]
+		pkts := matches[1]
+		bytes := matches[2]
+		comment := matches[3]
 
 		tags := map[string]string{"table": ipt.Table, "chain": mchain[1], "ruleid": comment}
 		fields := make(map[string]interface{})

plugins/inputs/iptables/iptables_test.go

@@ -154,9 +154,25 @@ func TestIptables_Gather(t *testing.T) {
 			tags:   []map[string]string{},
 			fields: [][]map[string]interface{}{},
 		},
+		{ // 11 - all target and ports
+			table:  "all_recv",
+			chains: []string{"accountfwd"},
+			values: []string{
+				`Chain accountfwd (1 references)
+						pkts bytes target prot opt in   out source    destination
+						 123   456        all  --  eth0 *   0.0.0.0/0 0.0.0.0/0   /* all_recv */
+		               `},
+			tags: []map[string]string{
+				map[string]string{"table": "all_recv", "chain": "accountfwd", "ruleid": "all_recv"},
+			},
+			fields: [][]map[string]interface{}{
+				{map[string]interface{}{"pkts": uint64(123), "bytes": uint64(456)}},
+			},
+		},
 	}
 
 	for i, tt := range tests {
+		t.Run(tt.table, func(t *testing.T) {
 			i++
 			ipt := &Iptables{
 				Table:  tt.table,
@@ -180,21 +196,21 @@ func TestIptables_Gather(t *testing.T) {
 				if n != 0 {
 					t.Errorf("%d: expected 0 fields if empty table got %d", i, n)
 				}
-			continue
+				return
 			}
 			if len(tt.chains) == 0 {
 				n := acc.NFields()
 				if n != 0 {
 					t.Errorf("%d: expected 0 fields if empty chains got %d", i, n)
 				}
-			continue
+				return
 			}
 			if len(tt.tags) == 0 {
 				n := acc.NFields()
 				if n != 0 {
 					t.Errorf("%d: expected 0 values got %d", i, n)
 				}
-			continue
+				return
 			}
 			n := 0
 			for j, tags := range tt.tags {
@@ -216,6 +232,7 @@ func TestIptables_Gather(t *testing.T) {
 					n++
 				}
 			}
+		})
 	}
 }