package rules import ( "fmt" "net/http" "strings" "github.com/gorilla/mux" "github.com/traefik/traefik/v2/pkg/log" "github.com/traefik/traefik/v2/pkg/middlewares/requestdecorator" "github.com/vulcand/predicate" ) var funcs = map[string]func(*mux.Route, ...string) error{ "Host": host, "HostHeader": host, "HostRegexp": hostRegexp, "Path": path, "PathPrefix": pathPrefix, "Method": methods, "Headers": headers, "HeadersRegexp": headersRegexp, "Query": query, } // Router handle routing with rules. type Router struct { *mux.Router parser predicate.Parser } // NewRouter returns a new router instance. func NewRouter() (*Router, error) { parser, err := newParser() if err != nil { return nil, err } return &Router{ Router: mux.NewRouter().SkipClean(true), parser: parser, }, nil } // AddRoute add a new route to the router. func (r *Router) AddRoute(rule string, priority int, handler http.Handler) error { parse, err := r.parser.Parse(rule) if err != nil { return fmt.Errorf("error while parsing rule %s: %w", rule, err) } buildTree, ok := parse.(treeBuilder) if !ok { return fmt.Errorf("error while parsing rule %s", rule) } if priority == 0 { priority = len(rule) } route := r.NewRoute().Handler(handler).Priority(priority) return addRuleOnRoute(route, buildTree()) } type tree struct { matcher string value []string ruleLeft *tree ruleRight *tree } func path(route *mux.Route, paths ...string) error { rt := route.Subrouter() for _, path := range paths { tmpRt := rt.Path(path) if tmpRt.GetError() != nil { return tmpRt.GetError() } } return nil } func pathPrefix(route *mux.Route, paths ...string) error { rt := route.Subrouter() for _, path := range paths { tmpRt := rt.PathPrefix(path) if tmpRt.GetError() != nil { return tmpRt.GetError() } } return nil } func host(route *mux.Route, hosts ...string) error { for i, host := range hosts { hosts[i] = strings.ToLower(host) } route.MatcherFunc(func(req *http.Request, _ *mux.RouteMatch) bool { reqHost := requestdecorator.GetCanonizedHost(req.Context()) if len(reqHost) == 0 { log.FromContext(req.Context()).Warnf("Could not retrieve CanonizedHost, rejecting %s", req.Host) return false } flatH := requestdecorator.GetCNAMEFlatten(req.Context()) if len(flatH) > 0 { for _, host := range hosts { if strings.EqualFold(reqHost, host) || strings.EqualFold(flatH, host) { return true } log.FromContext(req.Context()).Debugf("CNAMEFlattening: request %s which resolved to %s, is not matched to route %s", reqHost, flatH, host) } return false } for _, host := range hosts { if reqHost == host { return true } // Check for match on trailing period on host if last := len(host) - 1; last >= 0 && host[last] == '.' { h := host[:last] if reqHost == h { return true } } // Check for match on trailing period on request if last := len(reqHost) - 1; last >= 0 && reqHost[last] == '.' { h := reqHost[:last] if h == host { return true } } } return false }) return nil } func hostRegexp(route *mux.Route, hosts ...string) error { router := route.Subrouter() for _, host := range hosts { tmpRt := router.Host(host) if tmpRt.GetError() != nil { return tmpRt.GetError() } } return nil } func methods(route *mux.Route, methods ...string) error { return route.Methods(methods...).GetError() } func headers(route *mux.Route, headers ...string) error { return route.Headers(headers...).GetError() } func headersRegexp(route *mux.Route, headers ...string) error { return route.HeadersRegexp(headers...).GetError() } func query(route *mux.Route, query ...string) error { var queries []string for _, elem := range query { queries = append(queries, strings.Split(elem, "=")...) } route.Queries(queries...) // Queries can return nil so we can't chain the GetError() return route.GetError() } func addRuleOnRouter(router *mux.Router, rule *tree) error { switch rule.matcher { case "and": route := router.NewRoute() err := addRuleOnRoute(route, rule.ruleLeft) if err != nil { return err } return addRuleOnRoute(route, rule.ruleRight) case "or": err := addRuleOnRouter(router, rule.ruleLeft) if err != nil { return err } return addRuleOnRouter(router, rule.ruleRight) default: err := checkRule(rule) if err != nil { return err } return funcs[rule.matcher](router.NewRoute(), rule.value...) } } func addRuleOnRoute(route *mux.Route, rule *tree) error { switch rule.matcher { case "and": err := addRuleOnRoute(route, rule.ruleLeft) if err != nil { return err } return addRuleOnRoute(route, rule.ruleRight) case "or": subRouter := route.Subrouter() err := addRuleOnRouter(subRouter, rule.ruleLeft) if err != nil { return err } return addRuleOnRouter(subRouter, rule.ruleRight) default: err := checkRule(rule) if err != nil { return err } return funcs[rule.matcher](route, rule.value...) } } func checkRule(rule *tree) error { if len(rule.value) == 0 { return fmt.Errorf("no args for matcher %s", rule.matcher) } for _, v := range rule.value { if len(v) == 0 { return fmt.Errorf("empty args for matcher %s, %v", rule.matcher, rule.value) } } return nil }