Add a new protocol

Co-authored-by: Gérald Croës <gerald@containo.us>

rules/parser.go

@@ -29,6 +29,27 @@ func ParseDomains(rule string) ([]string, error) {
 	return lower(parseDomain(buildTree())), nil
 }
 
+// ParseHostSNI extracts the HostSNIs declared in a rule
+// This is a first naive implementation used in TCP routing
+func ParseHostSNI(rule string) ([]string, error) {
+	parser, err := newTCPParser()
+	if err != nil {
+		return nil, err
+	}
+
+	parse, err := parser.Parse(rule)
+	if err != nil {
+		return nil, err
+	}
+
+	buildTree, ok := parse.(treeBuilder)
+	if !ok {
+		return nil, errors.New("cannot parse")
+	}
+
+	return lower(parseDomain(buildTree())), nil
+}
+
 func lower(slice []string) []string {
 	var lowerStrings []string
 	for _, value := range slice {
@@ -41,7 +62,7 @@ func parseDomain(tree *tree) []string {
 	switch tree.matcher {
 	case "and", "or":
 		return append(parseDomain(tree.ruleLeft), parseDomain(tree.ruleRight)...)
-	case "Host":
+	case "Host", "HostSNI":
 		return tree.value
 	default:
 		return nil
@@ -95,3 +116,29 @@ func newParser() (predicate.Parser, error) {
 		Functions: parserFuncs,
 	})
 }
+
+func newTCPParser() (predicate.Parser, error) {
+	parserFuncs := make(map[string]interface{})
+
+	// FIXME quircky way of waiting for new rules
+	matcherName := "HostSNI"
+	fn := func(value ...string) treeBuilder {
+		return func() *tree {
+			return &tree{
+				matcher: matcherName,
+				value:   value,
+			}
+		}
+	}
+	parserFuncs[matcherName] = fn
+	parserFuncs[strings.ToLower(matcherName)] = fn
+	parserFuncs[strings.ToUpper(matcherName)] = fn
+	parserFuncs[strings.Title(strings.ToLower(matcherName))] = fn
+
+	return predicate.NewParser(predicate.Def{
+		Operators: predicate.Operators{
+			OR: orFunc,
+		},
+		Functions: parserFuncs,
+	})
+}