- 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.
inspect_tx_candidate assumes that htlc transactions have
only one input, which is not true for anchor channels.
inspect_tx_candidate is still used by the watchtower, because
it does not have access to channel information.
Due to malleability of HTLC-transactions, we can't send presigned
justice transactions for the second-stage HTLC transactions, which is
why we now send first-stage justice transactions for anchor channels.
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
* to_remote has now an additional csv lock of 1
* anchor outputs are added if to_local/remote outputs are present
* funder balance is reduced to accomodate anchors
* changes the htlc outputs' witness script to have a csv lock of 1
* send signatures for remote ctx with ANYONECANPAY|SINGLE
* refactor htlc weight (useful for zero-fee-htlc)
* in order to be able to sweep to_remote in an onchain backup scenario
we need to retain the private key for the payment_basepoint
* to facilitate the above, we open a channel derived from a static
secret (tied to the wallet seed), the static_payment_key combined with
the funding pubkey (multisig_key), which we can restore from the channel
closing transaction
- move some checks in two helper methods:
- invariant checks are performed in check_accepted_htlc
- mpp checks are performed in check_mpp_is waiting
- in order to avoid passing local_height to check_accepted_htlc,
the height in the error message is added by create_onion_error.
- do not fail because chain tip is stale if we already forwarded
- if we already forwarded a htlc and its cltv gets too close, do
not return, as this means we would never fulfill it
