Design IBC payload types for Sovereign rollup

[soareschen]

Summary

To properly build IBC messages to be sent from Sovereign to Cosmos, we need to design the IBC payload types for Sovereign to contain sufficient information that are fetched from the Sovereign rollup.

• The key difference of the Sovereign payloads as compared to the Cosmos payloads is that we need to use Jellyfish Merkle proofs to construct the proofs.
• It is not clear whether we can reuse the Cosmos types such as Proofs and CommitmentProofBytes.
• On the sovereign-ibc side, it looks like the proofs are returned in the form of Vec<u8> raw bytes, as a result, the relayer do not need to parse the proofs into the Jellyfish domain type
• There may need to be two payload types if we also need to fetch information from the DA
  • The rollup payload type only contain information fetched from the rollup
  • The chain payload type is a composition of the rollup payload, with additional DA information.
  • Other than client creation and update, it is unlikely that we need to interact with the DA for other IBC payloads. But this note is just in case if we need it.

Tasks

• Connection handshake payload types
  • Part of:
    • Implement connection open init from Sovereign to Cosmos #253
    • Implement connection open try from Sovereign to Cosmos #254
    • Implement connection open ack from Sovereign to Cosmos #260
    • Implement connection open confirm from Sovereign to Cosmos #255
• Channel handshake payload types
  • Part of:
    • Implement channel open init from Sovereign to Cosmos #256
    • Implement channel open try from Sovereign to Cosmos #257
    • Implement channel open ack from Sovereign to Cosmos #259
    • Implement channel open confirm from Sovereign to Cosmos #258
• Receive Packet payload
  • Part of Implement ReceivePacket relaying from Sovereign to Cosmos #273
  • Fill in SovereignReceivePacketRollupPayload
• Ack Packet payload
  • Part of Implement AckPacket relaying from Sovereign to Cosmos #276
  • Fill in SovereignAckPacketRollupPayload
• Timeout unordered packet payload
  • Part of Implement TimeoutUnorderedPacket relaying from Sovereign to Cosmos #278
  • Fill in SovereignTimeoutUnorderedPacketRollupPayload