Function parseECHConfigList

ech.go:139–164

parseECHConfigList parses a draft-ietf-tls-esni-18 ECHConfigList, returning a slice of parsed ECHConfigs, in the same order they were parsed, or an error if the list is malformed.

(data []byte)

// slice of parsed ECHConfigs, in the same order they were parsed, or an error
// if the list is malformed.
func parseECHConfigList(data []byte) ([]EchConfig, error) {
	s := cryptobyte.String(data)
	var length uint16
	if !s.ReadUint16(&length) {
		return nil, errMalformedECHConfigList
	}
	if length != uint16(len(data)-2) {
		return nil, errMalformedECHConfigList
	}
	var configs []EchConfig
	for len(s) > 0 {
		if len(s) < 4 {
			return nil, errors.New("tls: malformed ECHConfig")
		}
		configLen := uint16(s[2])<<8 | uint16(s[3])
		skip, ec, err := parseECHConfig(s)
		if err != nil {
			return nil, err
		}
		s = s[configLen+4:]
		if !skip {
			configs = append(configs, ec)
		}
	}
	return configs, nil
}

func pickECHConfig(list []EchConfig) *EchConfig {
	for _, ec := range list {