Electrum has an estimate-fee feature which takes as input the block you want a tx to be included.
The result is a recommendation of BTC/vbyte.
Using this recommendation and the knowledge about the size of our transactions we compute an appropriate fee.
The size of the transactions were taken from real transactions as published on bitcoin testnet.
Note: in reality these sizes might fluctuate a bit but not for much.
Alice chooses the fee for TxPunish because she is the one that cares.
Bob chooses the fee for TxRefund because he is the one that cares.
Note must be taken here because if the fee is too low (e.g. < min tx fee) then she might not be able to publish TxRedeem at all.
Alice chooses the fee for TxRedeem because she is the one that cares. Note must be taken here because if the fee is too low (e.g. < min tx fee) then she might not be able to publish TxRedeem at all.
Bob validates that incoming transfer proof messages are coming from the peer-id of Alice.
Currently Bob will ignore any transfer proof message that is not coming from the counterparty peer-id associated to the current swap in execution.
Once we add support for trying to save received transfer proofs for swaps that are currently not in execution we can also adapy allowing this for different counterparty peer-ids. This requires access to the database in Bob's event loop.
Alice validates that incoming encsig messages are coming from the peer-id that is associated with the swap.
Encsig message from a peer-id different to the one associated with the swap are ignored.
Instead of forwarding every error, we deliberately ignore certain
variants that are not worth being printed to the log. In particular,
this concerns "UnsupportedProtocols" and "ResponseOmission".
To make this less verbose we introduce a macro for mapping a
`RequestResponseEvent` to `{alice,bob}::OutEvent`. We use a macro
because those `OutEvent`s are different types and the only other
way of abstracting over them would be to introduce traits that we
implement on both of them.
To make the macro easier to use, we move all the `From` implementations
that convert between the protocol and the more high-level behaviour
into the actual protocol module.
405: Concurrent swaps with same peer r=da-kami a=da-kami
Fixes#367
- [x] Concurrent swaps with same peer
Not sure how much more time I should invest into this. We could just merge the current state and then do improvements on top...?
Improvements:
- [x] Think `// TODO: Remove unnecessary swap-id check` through and remove it
- [x] Add concurrent swap test, multiple swaps with same Bob
- [ ] Save swap messages without matching swap in execution in the database
- [ ] Assert the balances in the new concurrent swap tests
- [ ] ~~Add concurrent swap test, multiple swaps with different Bobs~~
- [ ] ~~Send swap-id in separate message, not on top of `Message0`~~
Co-authored-by: Daniel Karzel <daniel@comit.network>
- Swap-id is exchanged during execution setup. CLI (Bob) sends the swap-id to be used in his first message.
- Transfer poof and encryption signature messages include the swap-id so it can be properly associated with the correct swap.
- ASB: Encryption signatures are associated with swaps by swap-id, not peer-id.
- ASB: Transfer proofs are still associated to peer-ids (because they have to be sent to the respective peer), but the ASB can buffer multiple
- CLI: Incoming transfer proofs are checked for matching swap-id. If a transfer proof with a different swap-id than the current executing swap is received it will be ignored. We can change this to saving into the database.
Includes concurrent swap tests with the same Bob.
- One test that pauses and starts an additional swap after the transfer proof was received. Results in both swaps being redeemed after resuming the first swap.
- One test that pauses and starts an additional swap before the transfer proof is sent (just after BTC locked). Results in the second swap redeeming and the first swap being refunded (because the transfer proof on Bob's side is lost). Once we store transfer proofs that we receive during executing a different swap into the database both swaps should redeem.
Note that the monero harness was adapted to allow creating wallets with multiple outputs, which is needed for Alice.
It might very well be that the cancel transaction is already published.
If that is the case, there is no point in failing the command. We simply
transition to cancel and exit normally.
The reason this comes up now is because Alice now properly waits for
the cancel timelock as well and publishes the cancel transaction first.
Ultimately, she should not do that because there is no benefit to her
unless she can also publish the punish transaction.
Sending the transfer proof might never resolve because Bob doesn't
come back online. In that case, we need to make sure we bail out
as soon as the timelock expires.
We use the "precondition" feature of the `tokio::select!` macro to
avoid polling certain futures. In particular, we skip polling all
futures that - when resolved - require us to send a message to Alice.
This allows us to delay the ACKing of the encrypted signature up until
the swap has actually requested it.
Similarly, it allows us to wait for the ACK of the transfer proof within
the swap before continuing.
bmrng is a library providing a request-response channel that allows
the receiving end of the channel to send a response back to the sender.
This allows us to more accurately implement the functions on the
`EventLoopHandle`. In particular, we now _wait_ for the ACK of specific
messages from the other party before resolving the future.
For example, when sending the encrypted signature, the async function
on the `EventLoopHandle` does not resolve until we received the ACK
from the other party.
We also delete the `Channels` abstraction in favor of directly creating
bmrng channels. This allows us to directly control the channel buffer
which we set to 1 because we don't need more than that on Bob's side.
There is no point in first checking for the expired timelocks and
then constructing a `select!` that also watches for the timelock to
expiry.
We can simply only have the select! invocation to achieve the same
effect. In case the timelock is already expired, this future will
resolve immediately.
Normally, the polling order of `select!` is pseudo-random. We
configure it to be _biased_ here to make sure the futures are polled
in order.
The execution setup is our only libp2p protocol that doesn't have
a timeout built-in. Hence, if anything fails on Alice's side, we
would wait here forever.
Wrapping the future in a timeout ensures that we fail eventually
if this protocol doesn't succeed.
We don't need to hide the fields of this Behaviour as the only reason
for why this struct exists is because libp2p forces us to compose our
NetworkBehaviours into a new struct.
