func processNetworkFilters()

in xds/client/resource/filter_chain.go [588:687]
70 lines of code
19 McCabe index (conditional complexity)

func processNetworkFilters(filters []*v3listenerpb.Filter) (*FilterChain, error) {
	filterChain := &FilterChain{}
	seenNames := make(map[string]bool, len(filters))
	seenHCM := false
	for _, filter := range filters {
		name := filter.GetName()
		if name == "" {
			return nil, fmt.Errorf("network filters {%+v} is missing name field in filter: {%+v}", filters, filter)
		}
		if seenNames[name] {
			return nil, fmt.Errorf("network filters {%+v} has duplicate filter name %q", filters, name)
		}
		seenNames[name] = true

		// Network filters have a oneof field named `config_type` where we
		// only support `TypedConfig` variant.
		switch typ := filter.GetConfigType().(type) {
		case *v3listenerpb.Filter_TypedConfig:
			// The typed_config field has an `anypb.Any` proto which could
			// directly contain the serialized bytes of the actual filter
			// configuration, or it could be encoded as a `TypedStruct`.
			// TODO: Add support for `TypedStruct`.
			tc := filter.GetTypedConfig()

			// The only network filter that we currently support is the v3
			// HttpConnectionManager. So, we can directly check the type_url
			// and unmarshal the config.
			// TODO: Implement a registry of supported network filters (like
			// we have for HTTP filters), when we have to support network
			// filters other than HttpConnectionManager.
			if tc.GetTypeUrl() != version.V3HTTPConnManagerURL {
				return nil, fmt.Errorf("network filters {%+v} has unsupported network filter %q in filter {%+v}", filters, tc.GetTypeUrl(), filter)
			}
			hcm := &v3httppb.HttpConnectionManager{}
			if err := ptypes.UnmarshalAny(tc, hcm); err != nil {
				return nil, fmt.Errorf("network filters {%+v} failed unmarshaling of network filter {%+v}: %v", filters, filter, err)
			}
			// "Any filters after HttpConnectionManager should be ignored during
			// connection processing but still be considered for validity.
			// HTTPConnectionManager must have valid http_filters." - A36
			filters, err := processHTTPFilters(hcm.GetHttpFilters(), true)
			if err != nil {
				return nil, fmt.Errorf("network filters {%+v} had invalid server side HTTP Filters {%+v}: %v", filters, hcm.GetHttpFilters(), err)
			}
			if !seenHCM {
				// Validate for RBAC in only the HCM that will be used, since this isn't a logical validation failure,
				// it's simply a validation to support RBAC HTTP Filter.
				// "HttpConnectionManager.xff_num_trusted_hops must be unset or zero and
				// HttpConnectionManager.original_ip_detection_extensions must be empty. If
				// either field has an incorrect value, the Listener must be NACKed." - A41
				if hcm.XffNumTrustedHops != 0 {
					return nil, fmt.Errorf("xff_num_trusted_hops must be unset or zero %+v", hcm)
				}
				if len(hcm.OriginalIpDetectionExtensions) != 0 {
					return nil, fmt.Errorf("original_ip_detection_extensions must be empty %+v", hcm)
				}

				// TODO: Implement terminal filter logic, as per A36.
				filterChain.HTTPFilters = filters
				seenHCM = true
				if !envconfig.XDSRBAC {
					continue
				}
				switch hcm.RouteSpecifier.(type) {
				case *v3httppb.HttpConnectionManager_Rds:
					if hcm.GetRds().GetConfigSource().GetAds() == nil {
						return nil, fmt.Errorf("ConfigSource is not ADS: %+v", hcm)
					}
					name := hcm.GetRds().GetRouteConfigName()
					if name == "" {
						return nil, fmt.Errorf("empty route_config_name: %+v", hcm)
					}
					filterChain.RouteConfigName = name
				case *v3httppb.HttpConnectionManager_RouteConfig:
					// "RouteConfiguration validation logic inherits all
					// previous validations made for client-side usage as RDS
					// does not distinguish between client-side and
					// server-side." - A36
					// Can specify v3 here, as will never get to this function
					// if v2.
					routeU, err := generateRDSUpdateFromRouteConfiguration(hcm.GetRouteConfig(), nil, false)
					if err != nil {
						return nil, fmt.Errorf("failed to parse inline RDS resp: %v", err)
					}
					filterChain.InlineRouteConfig = &routeU
				case nil:
					return nil, fmt.Errorf("no RouteSpecifier: %+v", hcm)
				default:
					return nil, fmt.Errorf("unsupported type %T for RouteSpecifier", hcm.RouteSpecifier)
				}
			}
		default:
			return nil, fmt.Errorf("network filters {%+v} has unsupported config_type %T in filter %s", filters, typ, filter.GetName())
		}
	}
	if !seenHCM {
		return nil, fmt.Errorf("network filters {%+v} missing HttpConnectionManager filter", filters)
	}
	return filterChain, nil
}