Check size limits on metadata and name set from client. (#2850)

* Send error response when update metadata fails.

Keeping it simple for the first implementation.
- Send error response only if request_id != 0
- Two kinds of errors notified
  o does not have permissions - NOT_ALLOWED
  o attributes exceeds size limits -  INVALID_ARGUMENT

* Check size limits on metadata and name set from client.

Added a name length limit also.

* check name length in service update participant path also

* limit check in limit config

* update protocol

* longer keys

pkg/config/config.go

@@ -332,6 +332,31 @@ type LimitConfig struct {
 	MaxAttributesSize            uint32 `yaml:"max_attributes_size,omitempty"`
 	MaxRoomNameLength            int    `yaml:"max_room_name_length,omitempty"`
 	MaxParticipantIdentityLength int    `yaml:"max_participant_identity_length,omitempty"`
+	MaxParticipantNameLength     int    `yaml:"max_participant_name_length,omitempty"`
+}
+
+func (l LimitConfig) CheckRoomNameLength(name string) bool {
+	return l.MaxRoomNameLength == 0 || len(name) <= l.MaxRoomNameLength
+}
+
+func (l LimitConfig) CheckParticipantNameLength(name string) bool {
+	return l.MaxParticipantNameLength == 0 || len(name) <= l.MaxParticipantNameLength
+}
+
+func (l LimitConfig) CheckMetadataSize(metadata string) bool {
+	return l.MaxMetadataSize == 0 || uint32(len(metadata)) <= l.MaxMetadataSize
+}
+
+func (l LimitConfig) CheckAttributesSize(attributes map[string]string) bool {
+	if l.MaxAttributesSize == 0 {
+		return true
+	}
+
+	total := 0
+	for k, v := range attributes {
+		total += len(k) + len(v)
+	}
+	return uint32(total) <= l.MaxAttributesSize
 }
 
 type IngressConfig struct {
@@ -540,6 +565,7 @@ var DefaultConfig = Config{
 		MaxAttributesSize:            64000,
 		MaxRoomNameLength:            256,
 		MaxParticipantIdentityLength: 256,
+		MaxParticipantNameLength:     256,
 	},
 	Logging: LoggingConfig{
 		PionLevel: "error",