specs/standards/core/lightpush.md

4.1 KiB

title name editor contributors
WAKU-LIGHTPUSH Waku Light Push Zoltan Nagy <zoltan@status.im>
Hanno Cornelius <hanno@status.im>
Daniel Kaiser <danielkaiser@status.im>
Oskar Thorén <oskarth@titanproxy.com>

previous version: /vac/waku/lightpush/2.0.0-beta1 19/WAKU2-LIGHTPUSH


Protocol identifier: /vac/waku/lightpush/3.0.0

Motivation and Goals

Light nodes with short connection windows and limited bandwidth wish to push messages to other nodes in the Waku network to request message services. A common use case is to request that the service node publish the message to an 11/WAKU2-RELAY pubsub-topic. Additionally, there is sometimes a need for confirmation that a message has been received "by the network" (here, at least one node).

WAKU-LIGHTPUSH is a request/response protocol for this.

Payloads

syntax = "proto3";

message LightPushRequest {
    string request_id = 1;
    uin32 request_type = 10;  // 10 Reserved for future `request_type`. Currently, RELAY is the only available service.
    optional string pubsub_topic = 20;
    WakuMessage message = 21;
}

message LightPushResponse {
    string request_id = 1;
    uint32 status_code = 10; // non zero in case of failure, see appendix
    optional string status_desc = 11;
    uint32 relay_peer_count = 12; // number of peers, message is successfully relayed to 
}

Message Relaying

Nodes that respond to LightPushRequest MUST either relay the encapsulated message via 11/WAKU2-RELAY protocol on the specified pubsub_topic. Depending on the network configuration, the user may not need to provide pubsub_topic (WAKU2-RELAY-SHARDING). If they are unable to do so for some reason, they SHOULD return an error code in LightPushResponse. Once the relay is successful, the relay_peer_count will indicate the number of peers that the node has managed to relay the message to. It's important to note that this number may vary depending on the node subscriptions and support for the requested pubsub_topic. The client can use this information to either consider the relay as successful or take further action, such as switching to a lightpush service peer with better connectivity.

Examples of possible error codes

Result Code Note
SUCCESS 200 Successfull push, response's relay_peer_count holds the number of peers the message is pushed.
BAD_REQUEST 400 Wrong request payload.
PAYLOAD_TOO_LARGE 413 Message exceeds certain size limit, it can depend on network configuration, see status_desc for details.
UNSUPPORTED_TOPIC 421 Requested push on pubsub_topic is not possible as the service node does not support it.
TOO_MANY_REQUESTS 429 DOS protection prevented this request as the current request exceeds the configured request rate.
INTERNAL_SERVER_ERROR 500 status_desc holds explanation of the error.
NO_PEERS_TO_RELAY 503 Lightpush service is not available as the node has no relay peers.

The list of error codes is not complete and can be extended in the future.

Security Considerations

Since this can introduce an amplification factor, it is RECOMMENDED for the node relaying to the rest of the network to take extra precautions. Therefore Waku applies or will apply:

  • DOS protection through request rate limitation on the service itself.
  • message rate limiting via 17/WAKU2-RLN-RELAY, applied via network membership subscription.

These features are under development.

Future work

  • Add support attaching RLN proof for the message requested to be relayed.
  • Add support for other request types.
  • Incentivization of the service

Copyright and related rights waived via CC0.

References