Merge pull request #17 from MEschenbacher/icmp-type

Add match extension for icmp and icmp6
kilo-io · Mar 31, 2024 · 7eaddee · 7eaddee
2 parents fd02469 + 4bd1313
commit 7eaddee
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Showing 2 changed files with 146 additions and 0 deletions.
diff --git a/match_modules.go b/match_modules.go
@@ -30,6 +30,10 @@ func (p *Parser) parseMatch(ms *[]Match) (state, error) {
 		s, err = p.parseStatistic(&m.Flags)
 	case "multiport":
 		s, err = p.parseMultiport(&m.Flags)
+	case "icmp":
+		s, err = p.parseIcmp(&m.Flags)
+	case "icmp6":
+		s, err = p.parseIcmp6(&m.Flags)
 	default:
 		if _, ok := matchModules[lit]; ok {
 			return sError, fmt.Errorf("match modules %q is not implemented", lit)
@@ -529,3 +533,105 @@ func (p *Parser) parseComment(f *map[string]Flag) (state, error) {
 	}
 	return sStart, nil
 }
+
+func (p *Parser) parseIcmp(f *map[string]Flag) (state, error) {
+	s := sStart
+	for tok, lit := p.scanIgnoreWhitespace(); tok != EOF; tok, lit = p.scanIgnoreWhitespace() {
+		for nextValue := false; !nextValue; {
+			nextValue = true
+			switch s {
+			case sStart:
+				switch tok {
+				case NOT:
+					s = sINotF
+				case FLAG:
+					s = sIF
+					nextValue = false
+				default:
+					return sError, fmt.Errorf("unexpected token %q, expected flag, or \"!\"", lit)
+				}
+			case sINotF:
+				switch {
+				case lit == "--icmp-type":
+					_, lit := p.scanIgnoreWhitespace()
+					(*f)["icmp-type"] = Flag{
+						Not:    true,
+						Values: []string{lit},
+					}
+					s = sStart
+				default:
+					p.unscan(1)
+					return sNot, nil
+				}
+			case sIF:
+				switch {
+				case lit == "--icmp-type":
+					_, lit := p.scanIgnoreWhitespace()
+					(*f)["icmp-type"] = Flag{
+						Values: []string{lit},
+					}
+					s = sStart
+				default:
+					// The end of the match statement is reached.
+					p.unscan(1)
+					return sStart, nil
+				}
+
+			default:
+				return sStart, errors.New("unexpected error parsing match extension")
+			}
+		}
+	}
+	return sStart, nil
+}
+
+func (p *Parser) parseIcmp6(f *map[string]Flag) (state, error) {
+	s := sStart
+	for tok, lit := p.scanIgnoreWhitespace(); tok != EOF; tok, lit = p.scanIgnoreWhitespace() {
+		for nextValue := false; !nextValue; {
+			nextValue = true
+			switch s {
+			case sStart:
+				switch tok {
+				case NOT:
+					s = sINotF
+				case FLAG:
+					s = sIF
+					nextValue = false
+				default:
+					return sError, fmt.Errorf("unexpected token %q, expected flag, or \"!\"", lit)
+				}
+			case sINotF:
+				switch {
+				case lit == "--icmpv6-type":
+					_, lit := p.scanIgnoreWhitespace()
+					(*f)["icmpv6-type"] = Flag{
+						Not:    true,
+						Values: []string{lit},
+					}
+					s = sStart
+				default:
+					p.unscan(1)
+					return sNot, nil
+				}
+			case sIF:
+				switch {
+				case lit == "--icmpv6-type":
+					_, lit := p.scanIgnoreWhitespace()
+					(*f)["icmpv6-type"] = Flag{
+						Values: []string{lit},
+					}
+					s = sStart
+				default:
+					// The end of the match statement is reached.
+					p.unscan(1)
+					return sStart, nil
+				}
+
+			default:
+				return sStart, errors.New("unexpected error parsing match extension")
+			}
+		}
+	}
+	return sStart, nil
+}
diff --git a/parser_test.go b/parser_test.go
@@ -605,6 +605,46 @@ func TestParser_Parse(t *testing.T) {
 			},
 			err: nil,
 		},
+		{
+			name: "parse rule with icmp type",
+			s:    "-A foo -p icmp -m icmp --icmp-type 11",
+			r: Rule{
+				Chain: "foo",
+				Protocol: &StringPair{
+					Not:   false,
+					Value: "icmp",
+				},
+				Matches: []Match{
+					{
+						Type: "icmp",
+						Flags: map[string]Flag{
+							"icmp-type": {Values: []string{"11"}},
+						},
+					},
+				},
+			},
+			err: nil,
+		},
+		{
+			name: "parse rule with icmp type",
+			s:    "-A foo -p ipv6-icmp -m icmp6 --icmpv6-type 11",
+			r: Rule{
+				Chain: "foo",
+				Protocol: &StringPair{
+					Not:   false,
+					Value: "ipv6-icmp",
+				},
+				Matches: []Match{
+					{
+						Type: "icmp6",
+						Flags: map[string]Flag{
+							"icmpv6-type": {Values: []string{"11"}},
+						},
+					},
+				},
+			},
+			err: nil,
+		},
 		{
 			name: "parse rule with match expression tcp and a lot of flags and overwriting",
 			s:    "-A foo  -m tcp --tcp-flags SYN,FIN ACK --sport 1010 ! --dport=1000:1010  --syn! --syn  ! --tcp-option 1  ! -f ",