Valence ICA IBC Transfer Library

The Valence ICA IBC Transfer Library library allows remotely executing an IBC transfer using a Valence interchain account on a remote IBC connected domain. It does that by remotely sending a MsgTransfer to the ICA created by the Valence interchain account on the remote domain. It is typically used as part of a Valence Program. In that context, a Processor contract will be the main contract interacting with the Valence ICA IBC Transfer Library.

High-level flow

---
title: ICA IBC Transfer Library
---
graph LR
    subgraph Neutron
      P[Processor]
      L[ICA IBC
      Transfer Library]
      I[Input Account]
      P -- 1)Transfer --> L
      L -- 2)Query ICA address --> I
      L -- 3)Do ICA MsgTransfer --> I
    end

    subgraph Remote domain
      ICA[Interchain Account]
      I -- 4)Execute MsgTransfer --> ICA
    end

Functions

Configuration

The library is configured on instantiation via the LibraryConfig type.

#![allow(unused)]
fn main() {
pub struct LibraryConfig {
    // Address of the input account (Valence interchain account)
    pub input_addr: LibraryAccountType,
    // Amount that is going to be transferred
    pub amount: Uint128,
    // Denom that is going to be transferred
    pub denom: String,
    // Receiver on the other chain
    pub receiver: String,
    // Memo to be passed in the IBC transfer message.
    pub memo: String,
    // Remote chain info
    pub remote_chain_info: RemoteChainInfo,
    // Denom map for the Packet-Forwarding Middleware, to perform a multi-hop transfer.
    pub denom_to_pfm_map: BTreeMap<String, PacketForwardMiddlewareConfig>,
}

pub struct RemoteChainInfo {
    // Channel ID to be used
    pub channel_id: String,
    // Timeout for the IBC transfer in seconds. If not specified, a default 600 seconds will be used will be used
    pub ibc_transfer_timeout: Option<u64>,
}

// Configuration for a multi-hop transfer using the Packet Forwarding Middleware
struct PacketForwardMiddlewareConfig {
  // Channel ID from the source chain to the intermediate chain
  local_to_hop_chain_channel_id: String,
  // Channel ID from the intermediate to the destination chain
  hop_to_destination_chain_channel_id: String,
  // Temporary receiver address on the intermediate chain. Typically this is set to an invalid address so the entire transaction will revert if the forwarding fails. If not 
  // provided it's set to "pfm"
  hop_chain_receiver_address: Option<String>,
}
}

Packet-Forward Middleware

The library supports multi-hop IBC transfers using the Packet Forward Middleware (PFM). This allows tokens to be transferred through an intermediate chain to reach their final destination. More information about the PFM functionality can be found in the official documentation.

This works in the same way as the Generic IBC Transfer Library. The only difference is that the input account is a Valence interchain account and the receiver is a remote address on the remote domain. For more details on how PFM works, check the Generic IBC Transfer Library PFM documentation.