Fixes AbstractChannel.update_unfunded_state to stop calling a
non-existent method (unwatch_channel).
Adds unittest to execute the zeroconf path of update_unfunded_state.
Make the trampoline signaling in bolt11 invoices dependent upon all
unfrozen channels being with trampoline peers instead of the trampoline
config.
Stops automatically freezing non-trampoline channels for receiving if
trampoline is enabled.
One effect of this change is that now we don't signal trampoline support
anymore in the invoice even if trampoline is enabled, if one of the
channels is with a non trampoline peer.
"When should we reveal preimages onchain?"
This commit tries to simplify the thinking by making the observation:
- we can reveal preimages (actually in any context) if they are already public
- a preimage is public if any other lightning node knows it besides us
- if we learn the preimage from another LN node, it is public
- if we send update_fulfill_htlc, it becomes public
- if we see a preimage onchain, it is public
- in lnsweep._maybe_reveal_preimage_for_htlc:
- partial mpp check is not relevant if preimage is already public
- let's just always do KeepWatchingTXO, for sanity/safety
Co-authored-by: ThomasV <thomasv@electrum.org>
- LNWallet no longer "is-an" LNWorker, instead LNWallet "has-an" LNWorker
- the motivation is to make the unit tests nicer, and allow writing unit tests for more things
- I hope this makes it possible to e.g. test lnsweep in the unit tests
- some stuff we would previously have to write a regtest for, maybe we can write a unit test for, now
- in unit tests, MockLNWallet now
- inherits LNWallet
- the Wallet is no longer being mocked
If RHASH is in lnworker.dont_settle_htlcs, we should not reveal
the preimage. But also, we should not disregard the htlc either.
E.g. during a JIT channel open, payment going A->B->C,
C would release the preimage to B (lsp) to cover the costs of the
JIT channel-open. If the upstream A->B channel gets force-closed, B should
only pull the HTLC's funds if he is sure he can forward them to C.
lnwatcher needs to keep watching (i.e. wait) until the RHASH gets removed from
lnworker.dont_settle_htlcs, or until the CLTV of the HTLC expires.
We tried to delete incoming channels that didn't get funded after
lnutil.CHANNEL_OPENING_TIMEOUT, however an assert prevented this:
```
3.63 | E | lnwatcher.LNWatcher.[default_wallet-LNW] | Exception in check_onchain_situation: AssertionError()
Traceback (most recent call last):
File "/home/user/code/electrum-fork/electrum/util.py", line 1233, in wrapper
return await func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/user/code/electrum-fork/electrum/lnwatcher.py", line 117, in check_onchain_situation
await self.update_channel_state(
...<5 lines>...
keep_watching=keep_watching)
File "/home/user/code/electrum-fork/electrum/lnwatcher.py", line 135, in update_channel_state
chan.update_onchain_state(
~~~~~~~~~~~~~~~~~~~~~~~~~^
funding_txid=funding_txid,
^^^^^^^^^^^^^^^^^^^^^^^^^^
...<2 lines>...
closing_height=closing_height,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
keep_watching=keep_watching)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/user/code/electrum-fork/electrum/lnchannel.py", line 341, in update_onchain_state
self.update_unfunded_state()
~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/home/user/code/electrum-fork/electrum/lnchannel.py", line 382, in update_unfunded_state
self.lnworker.remove_channel(self.channel_id)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
File "/home/user/code/electrum-fork/electrum/lnworker.py", line 3244, in remove_channel
assert chan.can_be_deleted()
~~~~~~~~~~~~~~~~~~~^^
AssertionError
```
Deduct the just in time channel opening fees from the total amount so
htlcs don't get timed out if they come from a just in time channel with
opening fee.
Related: https://github.com/spesmilo/electrum/pull/9584
refactor `htlc_switch` to new architecture to make it more robust
against partial settlement of htlc sets and increase maintainability.
Htlcs are now processed in two steps, first the htlcs are collected into
sets from the channels, and potentially failed on their own already.
Then a second loop iterates over the htlc sets and finalizes only on
whole sets.
# Conflicts:
# electrum/lnpeer.py
Instead of storing its own path, each StoredDict element stores
its own key and a pointer to its parent. If a dict is removed
from the db, its parent pointer is set to None. This makes
self.path return None for all branches that have been pruned.
This passes tests/tests_json_db.py and fixes issue #10000
If a force-close happens due to e.g. a feerate disagreement or an invalid signature, etc,
and the remote peer sends us an error, it can be useful if users can provide us with this error.
If the user does not have logging enabled when the error is sent, without this persistence it will likely get lost.
- was added when functions in lnsweep returned already signed tx, and signing is expensive
- get_ctx_sweep_info does not presign anymore
- cache invalidation is difficult here
- e.g. not only on new blocks, but we should e.g. also invalidate the cache when learning new preimages
- if password is needed, await future and request it from GUI
- run asyncio task for each TxBatch, so that batches can
request the password concurrently
The threshold was added a long time ago before we considered running electrum as a forwarding node.
(also, 500k sats are now worth 20x more in fiat terms, lol)
Against a forwarding node, it is actually exploitable.
- Wallet.make_unsigned_transaction takes a FeePolicy parameter
- fee sliders act on a FeePolicy instead of config
- different fee policies may be used for different purposes
- do not detect dust outputs in lnsweep, delegate that to lnwatcher
Ideally, given an on-chain backup, after the remote force-closes, we should be able to spend our anchor output,
to CPFP the remote commitment tx (assuming the channel used OPTION_ANCHORS).
To spend the anchor output, we need to be able to sign with the local funding_privkey.
Previously we derived the funding_key from the channel_seed (which comes from os.urandom).
Prior to anchors, there was no use case for signing with the funding_key given a channel backup.
Now with anchors, we should make its derivation deterministic somehow, in a way so that it can
be derived given just an on-chain backup.
- one way would be to put some more data into the existing OP_RETURN
- uses block space
- the OP_RETURNs can be disabled via "use_recoverable_channels"
- only the initiator can use OP_RETURNs (so what if channel is in incoming dir?)
- instead, new scheme for our funding_key:
- we derive the funding_privkey from the lnworker root secret (derived from our bip32 seed)
- for outgoing channels:
- lnworker_root_secret + remote_node_id + funding_tx_nlocktime
- for incoming channels:
- lnworker_root_secret + remote_node_id + remote_funding_pubkey
- a check is added to avoid reusing the same key between channels:
not letting to user open more than one channel with the same peer in a single block
- only the first 16 bytes of the remote_node_id are used, as the onchain backup OP_RETURNs only contain that
- as the funding_privkey cannot be derived from the channel_seed anymore, it is included in the
imported channel backups, which in turn need a new version defined
- a wallet db upgrade is used to update already stored imported cbs
- alternatively we could keep the imported cbs as-is, so no new version, no new funding_privkey field, as it is clearly somewhat redundant given on-chain backups can reconstruct it
- however adding the field seems easier
- otherwise the existing code would try to derive the funding_privkey from the channel_seed
- also note: atm there is no field in the imported backups to distinguish anchor channels vs static-remotekey channels
- txins have an optional make_witness method
- instead of gen_tx, SweepInfo has a txin and
an optional txout, for 1st stage HTLCs
- sweep transactions are created by lnwatcher
The purpose of this change is to allow combining several
inputs in the same sweep transaction.
Due to anchor channel's sighash.SINGLE and sighash.ANYONECANPAY,
several HTLC-transactions can be combined. This means we must watch for
revoked outputs in the HTLC transaction not only at index 0 but at any
index.
naming scheme: tx(s)_our/their_ctx/htlctx_output-description
function names are shortened to whether a single (tx) or several sweep
transactions (txs) are generated
* sets the weight of htlc transactions to zero, thereby putting a zero
fee for the htlc transactions
* add inputs to htlc-tx for fee bumping
* switches feature flags
* disable anchor test vectors, which are now partially invalid
* add a method for backups to sweep to_remote
* to_remote sweeping needs the payment_basepoint's private key
to sign the sweep transaction
* we restore the private key from our funding multisig pubkey
(pubished with the closing transaction) and a static payment key secret
ThomasV