serai/docs/integrations/Instructions.md
Luke Parker 2ace339975
Tokens pallet (#243)
* Use Monero-compatible additional TX keys

This still sends a fingerprinting flare up if you send to a subaddress which
needs to be fixed. Despite that, Monero no should no longer fail to scan TXs
from monero-serai regarding additional keys.

Previously it failed becuase we supplied one key as THE key, and n-1 as
additional. Monero expects n for additional.

This does correctly select when to use THE key versus when to use the additional
key when sending. That removes the ability for recipients to fingerprint
monero-serai by receiving to a standard address yet needing to use an additional
key.

* Add tokens_primitives

Moves OutInstruction from in-instructions.

Turns Destination into OutInstruction.

* Correct in-instructions DispatchClass

* Add initial tokens pallet

* Don't allow pallet addresses to equal identity

* Add support for InInstruction::transfer

Requires a cargo update due to modifications made to serai-dex/substrate.

Successfully mints a token to a SeraiAddress.

* Bind InInstructions to an amount

* Add a call filter to the runtime

Prevents worrying about calls to the assets pallet/generally tightens things
up.

* Restore Destination

It was meged into OutInstruction, yet it didn't make sense for OutInstruction
to contain a SeraiAddress.

Also deletes the excessively dated Scenarios doc.

* Split PublicKey/SeraiAddress

Lets us define a custom Display/ToString for SeraiAddress.

Also resolves an oddity where PublicKey would be encoded as String, not
[u8; 32].

* Test burning tokens/retrieving OutInstructions

Modularizes processor_coinUpdates into a shared testing utility.

* Misc lint

* Don't use PolkadotExtrinsicParams
2023-01-28 01:47:13 -05:00

4.2 KiB

Instructions

Instructions are used to communicate with networks connected to Serai, and they come in two forms:

  • In Instructions are programmable specifications paired with incoming coins, encoded into transactions on connected networks. Serai will parse included instructions when it receives coins, executing the included specs.

  • Out Instructions detail how to transfer coins, either to a Serai address or an address native to the coin in question.

A transaction containing an In Instruction and an Out Instruction (to a native address) will receive coins to Serai and send coins from Serai, without requiring directly performing any transactions on Serai itself.

All instructions are encoded under Shorthand. Shorthand provides frequent use cases to create minimal data representations on connected networks.

Instructions are interpreted according to their non-Serai network. Addresses have no validation performed unless otherwise noted. If the processor is instructed to act on invalid data, it will drop the entire instruction.

Serialization

Instructions are SCALE encoded.

Application Call

  • application (u16): The application of Serai to call. Currently, only 0, Serai DEX is valid.
  • data (Data): The data to call the application with.

In Instruction

InInstruction is an enum of SeraiAddress and ApplicationCall.

The specified target will be minted an appropriate amount of the respective Serai token. If an Application Call, the encoded call will be executed.

Refundable In Instruction

  • origin (Option<ExternalAddress>): Address, from the network of origin, which sent coins in.
  • instruction (InInstruction): The action to perform with the incoming coins.

Networks may automatically provide origin. If they do, the instruction may still provide origin, overriding the automatically provided value.

If the instruction fails, coins are scheduled to be returned to origin, if provided.

Out Instruction

  • address (ExternalAddress): Address to transfer the coins included with this instruction to.
  • data (Option): Data to include when transferring coins.

No validation of external addresses/data is performed on-chain. If data is specified for a chain not supporting data, it is silently dropped.

Destination

Destination is an enum of SeraiAddress and OutInstruction.

Shorthand

Shorthand is an enum which expands to an Refundable In Instruction.

Raw

Raw Shorthand encodes a raw Refundable In Instruction in a Data, with no further processing. This is a verbose fallback option for infrequent use cases not covered by Shorthand.

Swap
  • origin (Option<ExternalAddress>): Refundable In Instruction's origin.
  • coin (Coin): Coin to swap funds for.
  • minimum (Amount): Minimum amount of coin to receive.
  • out (Destination): Final destination for funds.

which expands to:

RefundableInInstruction {
  origin,
  instruction: ApplicationCall {
    application: DEX,
    data:        swap(Incoming Asset, coin, minimum, out)
  }
}

where swap is a function which:

  1. Swaps the incoming funds for SRI.
  2. Swaps the SRI for coin.
  3. Checks the amount of coin received is greater than minimum.
  4. Executes out with the amount of coin received.
Add Liquidity
  • origin (Option<ExternalAddress>): Refundable In Instruction's origin.
  • minimum (Amount): Minimum amount of SRI tokens to swap half for.
  • gas (Amount): Amount of SRI to send to address to cover gas in the future.
  • address (Address): Account to send the created liquidity tokens.

which expands to:

RefundableInInstruction {
  origin,
  instruction: ApplicationCall {
    application: DEX,
    data:        swap_and_add_liquidity(Incoming Asset, minimum, gas, address)
  }
}

where swap_and_add_liquidity is a function which:

  1. Swaps half of the incoming funds for SRI.
  2. Checks the amount of SRI received is greater than minimum.
  3. Calls swap_and_add_liquidity with the amount of SRI received - gas, and a matching amount of the incoming coin.
  4. Transfers any leftover funds to address.